assignment function code

Destructuring assignment

The two most used data structures in JavaScript are Object and Array .

• Objects allow us to create a single entity that stores data items by key.
• Arrays allow us to gather data items into an ordered list.

However, when we pass these to a function, we may not need all of it. The function might only require certain elements or properties.

Destructuring assignment is a special syntax that allows us to “unpack” arrays or objects into a bunch of variables, as sometimes that’s more convenient.

Destructuring also works well with complex functions that have a lot of parameters, default values, and so on. Soon we’ll see that.

Array destructuring

Here’s an example of how an array is destructured into variables:

Now we can work with variables instead of array members.

It looks great when combined with split or other array-returning methods:

As you can see, the syntax is simple. There are several peculiar details though. Let’s see more examples to understand it better.

It’s called “destructuring assignment,” because it “destructurizes” by copying items into variables. However, the array itself is not modified.

It’s just a shorter way to write:

Unwanted elements of the array can also be thrown away via an extra comma:

In the code above, the second element of the array is skipped, the third one is assigned to title , and the rest of the array items are also skipped (as there are no variables for them).

…Actually, we can use it with any iterable, not only arrays:

That works, because internally a destructuring assignment works by iterating over the right value. It’s a kind of syntax sugar for calling for..of over the value to the right of = and assigning the values.

We can use any “assignables” on the left side.

For instance, an object property:

In the previous chapter, we saw the Object.entries(obj) method.

We can use it with destructuring to loop over the keys-and-values of an object:

The similar code for a Map is simpler, as it’s iterable:

There’s a well-known trick for swapping values of two variables using a destructuring assignment:

Here we create a temporary array of two variables and immediately destructure it in swapped order.

We can swap more than two variables this way.

The rest ‘…’

Usually, if the array is longer than the list at the left, the “extra” items are omitted.

For example, here only two items are taken, and the rest is just ignored:

If we’d like also to gather all that follows – we can add one more parameter that gets “the rest” using three dots "..." :

The value of rest is the array of the remaining array elements.

We can use any other variable name in place of rest , just make sure it has three dots before it and goes last in the destructuring assignment.

Default values

If the array is shorter than the list of variables on the left, there will be no errors. Absent values are considered undefined:

If we want a “default” value to replace the missing one, we can provide it using = :

Default values can be more complex expressions or even function calls. They are evaluated only if the value is not provided.

For instance, here we use the prompt function for two defaults:

Please note: the prompt will run only for the missing value ( surname ).

Object destructuring

The destructuring assignment also works with objects.

The basic syntax is:

We should have an existing object on the right side, that we want to split into variables. The left side contains an object-like “pattern” for corresponding properties. In the simplest case, that’s a list of variable names in {...} .

For instance:

Properties options.title , options.width and options.height are assigned to the corresponding variables.

The order does not matter. This works too:

The pattern on the left side may be more complex and specify the mapping between properties and variables.

If we want to assign a property to a variable with another name, for instance, make options.width go into the variable named w , then we can set the variable name using a colon:

The colon shows “what : goes where”. In the example above the property width goes to w , property height goes to h , and title is assigned to the same name.

For potentially missing properties we can set default values using "=" , like this:

Just like with arrays or function parameters, default values can be any expressions or even function calls. They will be evaluated if the value is not provided.

In the code below prompt asks for width , but not for title :

We also can combine both the colon and equality:

If we have a complex object with many properties, we can extract only what we need:

The rest pattern “…”

What if the object has more properties than we have variables? Can we take some and then assign the “rest” somewhere?

We can use the rest pattern, just like we did with arrays. It’s not supported by some older browsers (IE, use Babel to polyfill it), but works in modern ones.

It looks like this:

In the examples above variables were declared right in the assignment: let {…} = {…} . Of course, we could use existing variables too, without let . But there’s a catch.

This won’t work:

The problem is that JavaScript treats {...} in the main code flow (not inside another expression) as a code block. Such code blocks can be used to group statements, like this:

So here JavaScript assumes that we have a code block, that’s why there’s an error. We want destructuring instead.

To show JavaScript that it’s not a code block, we can wrap the expression in parentheses (...) :

Nested destructuring

If an object or an array contains other nested objects and arrays, we can use more complex left-side patterns to extract deeper portions.

In the code below options has another object in the property size and an array in the property items . The pattern on the left side of the assignment has the same structure to extract values from them:

All properties of options object except extra that is absent in the left part, are assigned to corresponding variables:

Finally, we have width , height , item1 , item2 and title from the default value.

Note that there are no variables for size and items , as we take their content instead.

Smart function parameters

There are times when a function has many parameters, most of which are optional. That’s especially true for user interfaces. Imagine a function that creates a menu. It may have a width, a height, a title, items list and so on.

Here’s a bad way to write such a function:

In real-life, the problem is how to remember the order of arguments. Usually IDEs try to help us, especially if the code is well-documented, but still… Another problem is how to call a function when most parameters are ok by default.

That’s ugly. And becomes unreadable when we deal with more parameters.

Destructuring comes to the rescue!

We can pass parameters as an object, and the function immediately destructurizes them into variables:

We can also use more complex destructuring with nested objects and colon mappings:

The full syntax is the same as for a destructuring assignment:

Then, for an object of parameters, there will be a variable varName for property incomingProperty , with defaultValue by default.

Please note that such destructuring assumes that showMenu() does have an argument. If we want all values by default, then we should specify an empty object:

We can fix this by making {} the default value for the whole object of parameters:

In the code above, the whole arguments object is {} by default, so there’s always something to destructurize.

Destructuring assignment allows for instantly mapping an object or array onto many variables.

The full object syntax:

This means that property prop should go into the variable varName and, if no such property exists, then the default value should be used.

Object properties that have no mapping are copied to the rest object.

The full array syntax:

The first item goes to item1 ; the second goes into item2 , all the rest makes the array rest .

It’s possible to extract data from nested arrays/objects, for that the left side must have the same structure as the right one.

We have an object:

Write the destructuring assignment that reads:

• name property into the variable name .
• years property into the variable age .
• isAdmin property into the variable isAdmin (false, if no such property)

Here’s an example of the values after your assignment:

The maximal salary

There is a salaries object:

Create the function topSalary(salaries) that returns the name of the top-paid person.

• If salaries is empty, it should return null .
• If there are multiple top-paid persons, return any of them.

P.S. Use Object.entries and destructuring to iterate over key/value pairs.

Open a sandbox with tests.

Open the solution with tests in a sandbox.

• If you have suggestions what to improve - please submit a GitHub issue or a pull request instead of commenting.
• If you can't understand something in the article – please elaborate.
• To insert few words of code, use the <code> tag, for several lines – wrap them in <pre> tag, for more than 10 lines – use a sandbox ( plnkr , jsbin , codepen …)

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Function assignment in javascript.

Used to call and/or provide the context (object) for a function that is dependant on an object. Often, functions are assigned to objects and access object members using the 'this' keyword.

Typically used when a function depends on different object types, or for passing parameters.

Function.prototype.call - JavaScript | MDN Function.prototype.apply - JavaScript | MDN Function.prototype.bind - JavaScript | MDN

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Destructuring assignment

The destructuring assignment syntax is a JavaScript expression that makes it possible to unpack values from arrays, or properties from objects, into distinct variables.

Description

The object and array literal expressions provide an easy way to create ad hoc packages of data.

The destructuring assignment uses similar syntax but uses it on the left-hand side of the assignment instead. It defines which values to unpack from the sourced variable.

Similarly, you can destructure objects on the left-hand side of the assignment.

This capability is similar to features present in languages such as Perl and Python.

For features specific to array or object destructuring, refer to the individual examples below.

Binding and assignment

For both object and array destructuring, there are two kinds of destructuring patterns: binding pattern and assignment pattern , with slightly different syntaxes.

In binding patterns, the pattern starts with a declaration keyword ( var , let , or const ). Then, each individual property must either be bound to a variable or further destructured.

All variables share the same declaration, so if you want some variables to be re-assignable but others to be read-only, you may have to destructure twice — once with let , once with const .

In many other syntaxes where the language binds a variable for you, you can use a binding destructuring pattern. These include:

• The looping variable of for...in for...of , and for await...of loops;
• Function parameters;
• The catch binding variable.

In assignment patterns, the pattern does not start with a keyword. Each destructured property is assigned to a target of assignment — which may either be declared beforehand with var or let , or is a property of another object — in general, anything that can appear on the left-hand side of an assignment expression.

Note: The parentheses ( ... ) around the assignment statement are required when using object literal destructuring assignment without a declaration.

{ a, b } = { a: 1, b: 2 } is not valid stand-alone syntax, as the { a, b } on the left-hand side is considered a block and not an object literal according to the rules of expression statements . However, ({ a, b } = { a: 1, b: 2 }) is valid, as is const { a, b } = { a: 1, b: 2 } .

If your coding style does not include trailing semicolons, the ( ... ) expression needs to be preceded by a semicolon, or it may be used to execute a function on the previous line.

Note that the equivalent binding pattern of the code above is not valid syntax:

You can only use assignment patterns as the left-hand side of the assignment operator. You cannot use them with compound assignment operators such as += or *= .

Default value

Each destructured property can have a default value . The default value is used when the property is not present, or has value undefined . It is not used if the property has value null .

The default value can be any expression. It will only be evaluated when necessary.

Rest property

You can end a destructuring pattern with a rest property ...rest . This pattern will store all remaining properties of the object or array into a new object or array.

The rest property must be the last in the pattern, and must not have a trailing comma.

Array destructuring

Basic variable assignment, destructuring with more elements than the source.

In an array destructuring from an array of length N specified on the right-hand side of the assignment, if the number of variables specified on the left-hand side of the assignment is greater than N , only the first N variables are assigned values. The values of the remaining variables will be undefined.

Swapping variables

Two variables values can be swapped in one destructuring expression.

Without destructuring assignment, swapping two values requires a temporary variable (or, in some low-level languages, the XOR-swap trick ).

Parsing an array returned from a function

It's always been possible to return an array from a function. Destructuring can make working with an array return value more concise.

In this example, f() returns the values [1, 2] as its output, which can be parsed in a single line with destructuring.

Ignoring some returned values

You can ignore return values that you're not interested in:

You can also ignore all returned values:

Using a binding pattern as the rest property

The rest property of array destructuring assignment can be another array or object binding pattern. The inner destructuring destructures from the array created after collecting the rest elements, so you cannot access any properties present on the original iterable in this way.

These binding patterns can even be nested, as long as each rest property is the last in the list.

On the other hand, object destructuring can only have an identifier as the rest property.

Unpacking values from a regular expression match

When the regular expression exec() method finds a match, it returns an array containing first the entire matched portion of the string and then the portions of the string that matched each parenthesized group in the regular expression. Destructuring assignment allows you to unpack the parts out of this array easily, ignoring the full match if it is not needed.

Using array destructuring on any iterable

Array destructuring calls the iterable protocol of the right-hand side. Therefore, any iterable, not necessarily arrays, can be destructured.

Non-iterables cannot be destructured as arrays.

Iterables are only iterated until all bindings are assigned.

The rest binding is eagerly evaluated and creates a new array, instead of using the old iterable.

Object destructuring

Basic assignment, assigning to new variable names.

A property can be unpacked from an object and assigned to a variable with a different name than the object property.

Here, for example, const { p: foo } = o takes from the object o the property named p and assigns it to a local variable named foo .

Assigning to new variable names and providing default values

A property can be both

• Unpacked from an object and assigned to a variable with a different name.
• Assigned a default value in case the unpacked value is undefined .

Unpacking properties from objects passed as a function parameter

Objects passed into function parameters can also be unpacked into variables, which may then be accessed within the function body. As for object assignment, the destructuring syntax allows for the new variable to have the same name or a different name than the original property, and to assign default values for the case when the original object does not define the property.

Consider this object, which contains information about a user.

Here we show how to unpack a property of the passed object into a variable with the same name. The parameter value { id } indicates that the id property of the object passed to the function should be unpacked into a variable with the same name, which can then be used within the function.

You can define the name of the unpacked variable. Here we unpack the property named displayName , and rename it to dname for use within the function body.

Nested objects can also be unpacked. The example below shows the property fullname.firstName being unpacked into a variable called name .

Setting a function parameter's default value

Default values can be specified using = , and will be used as variable values if a specified property does not exist in the passed object.

Below we show a function where the default size is 'big' , default co-ordinates are x: 0, y: 0 and default radius is 25.

In the function signature for drawChart above, the destructured left-hand side has a default value of an empty object = {} .

You could have also written the function without that default. However, if you leave out that default value, the function will look for at least one argument to be supplied when invoked, whereas in its current form, you can call drawChart() without supplying any parameters. Otherwise, you need to at least supply an empty object literal.

For more information, see Default parameters > Destructured parameter with default value assignment .

Nested object and array destructuring

For of iteration and destructuring, computed object property names and destructuring.

Computed property names, like on object literals , can be used with destructuring.

Invalid JavaScript identifier as a property name

Destructuring can be used with property names that are not valid JavaScript identifiers by providing an alternative identifier that is valid.

Destructuring primitive values

Object destructuring is almost equivalent to property accessing . This means if you try to destruct a primitive value, the value will get wrapped into the corresponding wrapper object and the property is accessed on the wrapper object.

Same as accessing properties, destructuring null or undefined throws a TypeError .

This happens even when the pattern is empty.

Combined array and object destructuring

Array and object destructuring can be combined. Say you want the third element in the array props below, and then you want the name property in the object, you can do the following:

The prototype chain is looked up when the object is deconstructed

When deconstructing an object, if a property is not accessed in itself, it will continue to look up along the prototype chain.

Specifications

Browser compatibility.

BCD tables only load in the browser with JavaScript enabled. Enable JavaScript to view data.

• Assignment operators
• ES6 in Depth: Destructuring on hacks.mozilla.org (2015)

DoD Function Codes

The Total Force Manpower & Resources Directorate (TFM&RS) within the Office of the Under Secretary of Defense for Personnel and Readiness, Manpower and Reserve Affairs (OUSD P&R/M&RA) maintains a list of Department of Defense (DoD) function codes that identify the type of work performed by all activities in the defense infrastructure and operating forces. Every manpower authorization (or billet)—to include active, reserve, and civilian—is assigned a DoD function code to describe the work performed. This coding occurs in authoritative manpower systems and is critical to articulating the size and composition of the department’s workforce from a perspective of requirements and work being performed rather than personnel inventory.

Historically, DoD function codes, submitted annually in the Inherently Governmental and Commercial Activities (IG/CA) Inventory, have been relied on to identify work that could be considered for competition with the private sector and have been associated with the Office of Management and Budget (OMB) Circular A-76 processes. Although the A-76 program has been suspended, the congressional reporting requirement remains. Further, the pressure to shape the total force effectively and economically—coupled with sustained scrutiny on the size, shape, structure, and workload alignment across the total force—means that these function codes must remain relevant and current.

The current set of function codes, however, has not been reviewed or updated in over a decade. The codes do not reflect (among other things) emergent domains and operations, such as cyberspace and unmanned systems. They also do not reflect areas that have received significant congressional or departmental attention in recent years, such as operational contract support planning, force resiliency functions, and security cooperation activities, to name a few. TFM&RS asked CNA to review the function codes to determine their currency and relevancy and to update and revise the codes accordingly.

Our recommendations contain revisions to the current DoD function codes. Significant recommended additions include new or revised codes for the following functional areas:

• Security cooperation
• Operational contract support
• Unmanned systems

We also recommend the revision or relocation of many existing function codes. Details on these recommended revisions can be found in Appendix A. In addition, we recommend revisions to the organization of the codes, such as removing the Infrastructure category and the Forces and Direct Support category to eliminate the need to duplicate certain functions that are performed in both the infrastructure and the operating forces and to allow for more precise coding of functions performed in the operating forces. We also recommend revisions to the coding guidance, such as coding functions based strictly on the work being performed regardless of where that work is performed or if that work is closely associated with another function.

We provide recommendations to improve the currency and accuracy of the function codes in authoritative manpower systems. Our discussions with the Services, Joint Staff, and other DoD offices revealed that existing function codes are not reviewed and updated in authoritative manpower systems regularly; function codes typically remain unchanged from year to year even if a change to the billet warrants a review of the function code. We heard several suggestions for mitigating these issues. Among the most compelling is an OSD policy that requires function codes to be included in billet change requests. Components could also adopt a system that allows for the automated checking of DoD function code assignment when another billet element is changed.

More oversight is required to improve the quality of function code data as part of the annual IG/CA Inventory data submission. Whereas all components’ IG/CA Inventories were previously subjected to a quality control process, reviewed extensively for errors, and analyzed to ensure consistency, little attention has been paid to the quality of IG/CA Inventory data since the A-76 program was suspended. The data should again be subjected to a rigorous quality control process and analysis to ensure that the data fields are being consistently used and populated by the components.

Another recommendation to improve the quality of the data is to develop training for those responsible for applying function codes. Ideally, manpower analysts/specialists with knowledge of the work being performed in the billets would be applying, reviewing, and updating the codes as necessary. In reality, the personnel applying function codes to billets often do not understand the purpose of function codes or the work being performed in the billets. Instead, they rely on the occupation code of the person sitting in the billet to assign a function code. This is problematic because often the occupation code of the person in the billet does not match the work being performed by that person. Training a cadre of personnel across DoD on how to use function codes would ensure greater accuracy and consistency in how function codes are applied across the department. More consistent functional coding would enable better manpower analysis across DoD and is a critical step to improving the data necessary for a reconstituted A-76 program.

In addition to ensuring that the data are reviewed and updated periodically and subjected to a quality control process, the larger purpose and value of function codes need to be communicated by OSD leadership. Although some components indicated that they use function codes to conduct manpower analysis, others expressed the opinion that function codes were not useful outside of fulfilling the IG/CA Inventory requirement. Further, many of the OSD Functional Community Managers (OFCMs) and some DoD offices we met with were unfamiliar with function codes and how they differ from occupation codes. Therefore, we recommend that OSD communicate the intent and purpose of function codes as well as the value of accurate and up-to-date functional coding for manpower analysis and workforce mix decision-making throughout DoD. Function codes are currently the only formal construct that bridges military and civilian billets performing similar work; the purpose and value of these data need to be conveyed by leadership.

Finally, we recommend that components explore the value of adding a secondary function code to their authoritative manpower systems. A secondary function code would provide visibility on functions being performed in addition to the primary function. At the time of the discussions, all of the Services indicated that a secondary function code would not be useful to them. Concerns were expressed about the cost to add a secondary function code field to authoritative manpower databases as well as the manpower required to assess and assign a secondary function. At a later discussion with Navy personnel, however, we learned that the Navy has decided to add two additional function code fields in its authoritative manpower system, the Total Force Manpower Management System (TFMMS). Although it isn’t yet clear how the Navy intends to use these fields, it will be informative to watch how the Navy decides to use them and to assess the costs and benefits of adding the additional fields.

Approved for public release: distribution unlimited.

• Document Number: DRM-2019-U-019326-Final
• Publication Date: 4/22/2019

C++ Tutorial

C++ functions, c++ classes, c++ reference, c++ examples, c++ assignment operators, assignment operators.

Assignment operators are used to assign values to variables.

In the example below, we use the assignment operator ( = ) to assign the value 10 to a variable called x :

The addition assignment operator ( += ) adds a value to a variable:

A list of all assignment operators:

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Assignment operators.

Assignment operators modify the value of the object.

[ edit ] Definitions

Copy assignment replaces the contents of the object a with a copy of the contents of b ( b is not modified). For class types, this is performed in a special member function, described in copy assignment operator .

For non-class types, copy and move assignment are indistinguishable and are referred to as direct assignment .

Compound assignment replace the contents of the object a with the result of a binary operation between the previous value of a and the value of b .

[ edit ] Assignment operator syntax

The assignment expressions have the form

• ↑ target-expr must have higher precedence than an assignment expression.
• ↑ new-value cannot be a comma expression, because its precedence is lower.

[ edit ] Built-in simple assignment operator

For the built-in simple assignment, the object referred to by target-expr is modified by replacing its value with the result of new-value . target-expr must be a modifiable lvalue.

The result of a built-in simple assignment is an lvalue of the type of target-expr , referring to target-expr . If target-expr is a bit-field , the result is also a bit-field.

[ edit ] Assignment from an expression

If new-value is an expression, it is implicitly converted to the cv-unqualified type of target-expr . When target-expr is a bit-field that cannot represent the value of the expression, the resulting value of the bit-field is implementation-defined.

If target-expr and new-value identify overlapping objects, the behavior is undefined (unless the overlap is exact and the type is the same).

In overload resolution against user-defined operators , for every type T , the following function signatures participate in overload resolution:

For every enumeration or pointer to member type T , optionally volatile-qualified, the following function signature participates in overload resolution:

For every pair A1 and A2 , where A1 is an arithmetic type (optionally volatile-qualified) and A2 is a promoted arithmetic type, the following function signature participates in overload resolution:

[ edit ] Built-in compound assignment operator

The behavior of every built-in compound-assignment expression target-expr   op   =   new-value is exactly the same as the behavior of the expression target-expr   =   target-expr   op   new-value , except that target-expr is evaluated only once.

The requirements on target-expr and new-value of built-in simple assignment operators also apply. Furthermore:

• For + = and - = , the type of target-expr must be an arithmetic type or a pointer to a (possibly cv-qualified) completely-defined object type .
• For all other compound assignment operators, the type of target-expr must be an arithmetic type.

In overload resolution against user-defined operators , for every pair A1 and A2 , where A1 is an arithmetic type (optionally volatile-qualified) and A2 is a promoted arithmetic type, the following function signatures participate in overload resolution:

For every pair I1 and I2 , where I1 is an integral type (optionally volatile-qualified) and I2 is a promoted integral type, the following function signatures participate in overload resolution:

For every optionally cv-qualified object type T , the following function signatures participate in overload resolution:

[ edit ] Example

Possible output:

[ edit ] Defect reports

The following behavior-changing defect reports were applied retroactively to previously published C++ standards.

[ edit ] See also

Operator precedence

Operator overloading

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C++ Assignment Operator Overloading

• Operator Overloading in C++
• Assignment Operators in Programming
• Operator Overloading in MATLAB
• C++ Bitwise Operator Overloading
• Solidity - Assignment Operators
• Operator Overloading in Julia
• Operator Overloading in Ruby
• Operator Overloading in Python
• C++ Logical (&&, ||, !) Operator Overloading
• Assignment Operators In C++
• Types of Operator Overloading in C++
• Assignment Operators in C
• Overloading New and Delete operator in c++
• Increment (++) and Decrement (--) Operator Overloading in C++
• C++ | Operator Overloading | Question 3
• C++ | Operator Overloading | Question 9
• C++ | Operator Overloading | Question 7
• C++ | Operator Overloading | Question 2
• C++ | Operator Overloading | Question 6
• Vector in C++ STL
• Initialize a vector in C++ (7 different ways)
• Map in C++ Standard Template Library (STL)
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Prerequisite: Operator Overloading

The assignment operator,”=”, is the operator used for Assignment. It copies the right value into the left value. Assignment Operators are predefined to operate only on built-in Data types.

• Assignment operator overloading is binary operator overloading.
• Overloading assignment operator in C++ copies all values of one object to another object.
• Only a non-static member function should be used to overload the assignment operator.

We can’t directly use the Assignment Operator on objects. The simple explanation for this is that the Assignment Operator is predefined to operate only on built-in Data types. As the class and objects are user-defined data types, so the compiler generates an error.

here, a and b are of type integer, which is a built-in data type. Assignment Operator can be used directly on built-in data types.

c1 and c2 are variables of type “class C”. Here compiler will generate an error as we are trying to use an Assignment Operator on user-defined data types.

The above example can be done by implementing methods or functions inside the class, but we choose operator overloading instead. The reason for this is, operator overloading gives the functionality to use the operator directly which makes code easy to understand, and even code size decreases because of it. Also, operator overloading does not affect the normal working of the operator but provides extra functionality to it.

Now, if the user wants to use the assignment operator “=” to assign the value of the class variable to another class variable then the user has to redefine the meaning of the assignment operator “=”.  Redefining the meaning of operators really does not change their original meaning, instead, they have been given additional meaning along with their existing ones.

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Functions in Python – Explained with Code Examples

In any programming language, functions facilitate code reusability . In simple terms, when you want to do something repeatedly, you can define that something as a function and call that function whenever you need to.

In this tutorial, we shall learn about user-defined functions in Python.

When you started coding in Python, you'd have used the built-in print() function in your Hello World! program 😀 and the input() function to read in input from the user.

So long as you know how to use these functions, you don't have to worry about how they've been implemented.

In programming, this is called abstraction. It lets you use functions by calling the function with required arguments, without having to worry about how they actually work.

There's a whole wealth of built-in functions in Python. In this post, we shall see how we can define and use our own functions. Let's get started!

Python Function Syntax

The following snippet shows the general syntax to define a function in Python:

• You need to use the def keyword, give your function a name, followed by a pair of parentheses, and end the line with a colon (:).
• If your function takes arguments, the names of the arguments (parameters) are mentioned inside the opening and closing parentheses.
• Please note that in function definition, the arguments that your function consumes are referred to as parameters .
• When you call the function with specific values for these parameters, they're called arguments or actual parameters. This is because the arguments in the function call are the values used for the function's parameters.
• Then, you begin an indented block. This is the body of the function that describes what your function does.
• There's a return statement that returns the result of the operation on the arguments. The return statement returns control to the point where the function was originally called.

Note that the arguments and the return statement are optional. This means that you could have a function that takes in no arguments , and returns nothing . 😀

Let's now try to understand the above statements using simple examples.

How to Create a Simple Function in Python

Let's now create a simple function in Python that greets the user, as shown below:

As you can see, the function my_func() :

• takes no arguments,
• returns nothing, and
• prints out "Hello! Hope you're doing well" whenever it's called .

Note that the above function definition is inert until the function is triggered or called. Let's go ahead and call the function my_func() and check the output.

How to Create a Function with Arguments in Python

Now, we shall modify the function my_func() to include the name and place of the user.

We can now call my_func() by passing in two strings for the name and place of the user, as shown below.

What happens if you specify the place first and then the name ? Let's find out.

We get Hello Hawaii! Are you from Robert? – and this doesn't make sense. 🙂What's causing this problem?

The arguments in the function call are positional arguments . This means that the first argument in the function call is used as the value of the first parameter ( name )  and the second argument in the function call is used as the value of the second parameter ( place )

See the code snippet below. Instead of specifying only the arguments, we've mentioned the parameters and the values they take.

These are called keyword arguments. The order of arguments in the function call does not matter so long as the names of the parameters are correct.

How to Create a Function with Default Arguments in Python

What if we had certain parameters that take a specific value most of the time during the function calls?

Can we not do better than calling the function with the same value for a particular parameter?

Yes we can do better, and that's what default arguments are for! 😀

Let's create a function total_calc() that helps us calculate and print out the total amount to be paid at a restaurant. Given a bill_amount and the percentage of the bill_amount you choose to pay as tip ( tip_perc ), this function calculates the total amount that you should pay.

Note how the function definition includes the default value of the parameter tip_perc to be used when the user doesn't specify a tip percentage.

Run the code snippet below.👇🏽 You now have your function ready!

Let's now call the function in a few different ways. The code snippet below shows the following:

• When you call the function total_calc with only the bill_amount , by default the tip percentage of 10 is used.
• When you explicitly specify the percentage tip, the tip percentage mentioned in the function call is used.

How to Create a Function that Returns a Value in Python

So far, we've only created functions that may or may not take arguments and do not return anything. Now, let's create a simple function that returns the volume of a cuboid given the length , the width , and the height .

Recall that the return keyword returns control to the point where the function was called. The function call is replaced with the return value from the function.

Let's call the function volume_of_cuboid() with the necessary dimension arguments, as shown in the code snippet below. Note how we use the variable volume to capture the value returned from the function.

How to Create a Function that Returns Multiple Values in Python

In our earlier example, the function volume_of_cuboid() returned only one value, namely, the volume of a cuboid given its dimensions. Let's see how we can return multiple values from a function.

• To return multiple values from a function, just specify the values to be returned, separated by a comma.
• By default, the function returns the values as a tuple. If there are N return values, we get an N- tuple.

Let's create a simple function cube() that returns the volume and total surface area of a cube, given the length of its side.

To verify that a tuple is returned, let's collect it in a variable returned_values , as shown below:

Now, we shall unpack the tuple and store the values in two different variables.

How to Create a Function that Takes a Variable Number of Arguments in Python

Let's start by asking a few questions:

• What if we do not know the exact number of arguments beforehand?
• Can we create functions that work with a variable number of arguments?

The answer is yes! And we'll create such a function right away.

Let's create a simple function my_var_sum() that returns the sum of all numbers passed in as the argument. However, the number of arguments could be potentially different each time we call the function.

Notice how the function definition now has *args instead of just the name of the parameter. In the body of the function, we loop through args until we've used all the arguments. The function my_var_sum returns the sum of all numbers passed in as arguments.

Let's now call the function my_var_sum() with a different number of arguments each time and quickly check if the returned answers are correct! 🙂

⌛ A Quick Recap

Let's quickly summarize what we've covered. In this tutorial, we've learned:

• how to define functions,
• how to pass in arguments to a function,
• how to create functions with default and variable number of arguments, and
• how to create a function with return value(s).

Hope you all enjoyed reading this article. Thank you for reading. As always, until next time! 😀

I am a developer and technical writer from India. I write tutorials on all things programming and machine learning.

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Statistics Made Easy

How to Use the assign() Function in R (3 Examples)

The assign() function in R can be used to assign values to variables.

This function uses the following basic syntax:

assign(x, value)

• x : A variable name, given as a character string.
• value : The value(s) to be assigned to x.

The following examples show how to use this function in practice.

Example 1: Assign One Value to One Variable

The following code shows how to use the assign() function to assign the value of 5 to a variable called new_variable:

When we print the variable called new_variable , we can see that a value of 5 appears.

Example 2: Assign Vector of Values to One Variable

The following code shows how to use the assign() function to assign a vector of values to a variable called new_variable:

When we print the variable called new_variable , we can see that a vector of values appears.

Example 3: Assign Values to Several Variables

The following code shows how to use the assign() function within a for loop to assign specific values to several new variables:

By using the assign() function with a for loop, we were able to create four new variables.

Additional Resources

The following tutorials explain how to use other common functions in R:

How to Use the dim() Function in R How to Use the table() Function in R How to Use sign() Function in R

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Hey there. My name is Zach Bobbitt. I have a Masters of Science degree in Applied Statistics and I’ve worked on machine learning algorithms for professional businesses in both healthcare and retail. I’m passionate about statistics, machine learning, and data visualization and I created Statology to be a resource for both students and teachers alike.  My goal with this site is to help you learn statistics through using simple terms, plenty of real-world examples, and helpful illustrations.

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