How to call a list in a function python

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Using map() method
Using list comprehensions
Using Lambda Function
Pass a List to a Function in Python
Pass a List to a Python Function Just Like Any Other Data Type
Difference Between Passing and Unpacking a List in Python
Related Article - Python Function
Can you pass a list to a function in Python?
How do you input a list into a function in Python?
How do you access a list from another function in Python?
Can you call a function within a list Python?

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In this article, we will learn how to apply a function to each element of a Python list. Let’s see what exactly is Applying a function to each element of a list means:

Suppose we have a list of integers and a function that doubles each integer in this list. On applying the function to the list, the function should double all the integers in the list. We achieve this functionality in the following ways:

map() method.
Using list comprehensions.
lambda function

Using map() method

map() methods take two arguments: iterables and functions and returns a map object. We use list() to convert the map object to a list.

Program:

Python3

def double(integer):

return integer*2

integer_list = [1, 2, 3]

output_list = list(map(double, integer_list))

print(output_list)

Output:

[2, 4, 6]

Time Complexity: O(n)*(O complexity of function applied on list)

Using list comprehensions

We use a list comprehension to call a function on each element of the list and then double it for this case.

Program:

Python3

def double(integer):

return integer*2

integer_list = [1, 2, 3]

output_list = [double(i) for i in integer_list]

print(output_list)

Output:

[2, 4, 6]

Time Complexity: O(n)*(O complexity of function applied on list)

Using Lambda Function

A lambda function can also be employed to produce the above functionality. Lambda is capable of creating an anonymous function that can be made enough to fit the given requirement.

Program:

Python3

lst = [1, 2, 3]

ans = []

for x in lst:

def res(x): return x*2

ans.append(res(x))

print(ans)

Output:

[2, 4, 6]

HowTo
Python How-To's
Pass a List to a Function in Python

Created: March-05, 2022

Pass a List to a Function in Python
Pass a List to a Python Function Just Like Any Other Data Type
Difference Between Passing and Unpacking a List in Python
Conclusion

In Python, sending a list to a function is just like passing any other form of data. Let’s explore a little more into this subject.

Pass a List to a Function in Python

We will define a function testing with a single parameter, flavor. Then, we pass an argument named Cherry while calling the function.

This argument goes to the parameter variable flavor, which the function can then use. See the example below.

Code:

def testing(flavor):
    print("You chose:", flavor)

testing("Cherry")

Output:

You chose: Cherry

Pass a List to a Python Function Just Like Any Other Data Type

Python lists are like any other Python object that we can pass into a function as a simple variable. We have a function enjoy with a hobbies parameter in the code sample below.

Outside the function block, we define a list hobbies_list. While calling the function enjoy, we pass this variable, hobbies_list, as an argument.

This list goes to the parameter variable hobbies, and thus, the function can use the value of this list.

Code:

def enjoy(hobbies): #or def enjoy(hobbies=[]):
    for hobby in hobbies:
        print(hobby)

hobbies_list = ['art', 'dance', 'sing']
enjoy(hobbies_list)

Output:

art
dance
sing

See how the enjoy function gets the value of the list, and the for loop inside it prints all the list items. Sometimes, you will also see the assignment of square brackets [] to the parameter variable while passing a list to a function.

Difference Between Passing and Unpacking a List in Python

In Python, we can use *args to pass a variable number of arguments to a function. Now, since a list has multiple values, people tend to use *args as the parameter variable for a list argument so that all the values of the list are taken care of.

When we define *args as the parameter variable, we signal the function to wait for a variable number of arguments. Passing the elements of a list as multiple arguments is similar to unpacking a list.

Code:

def subjects(*args):
    for subject in args:
        print("The subject name is ",subject)

names = ['mathematics', 'science', 'history']
subjects(names)

Output:

The subject name is  ['mathematics', 'science', 'history']

You will see the difference better if you compare this output with the below code.

Code:

def subjects(args):
    for subject in args:
        print("The subject name is ", subject)

names = ['mathematics', 'science', 'history']
subjects(names)

Output:

The subject name is  mathematics
The subject name is  science
The subject name is  history

Notice how the output changes based on *args. If *args is used to pass a list to a Python function, we might not get the expected results.

As a result, it’s important to select the appropriate syntax based on the requirements.

Conclusion

In this article, we learned about passing a list to a function in Python. We saw how we could pass a list to a function in Python just like we pass any other data type.

We further understood the difference between passing and unpacking lists as multiple arguments.

Exit a Function in Python

Optional Arguments in Python

Python Function Parameter Type

Imitate ode45() Function in Python

Can you pass a list to a function in Python?

You can send any data types of argument to a function (string, number, list, dictionary etc.), and it will be treated as the same data type inside the function.

How do you input a list into a function in Python?

Python input and output exercise..

First, create an empty list..

Next, accept a list size from the user (i.e., the number of elements in a list).

Run loop till the size of a list using a for loop and range() function..

use the input() function to receive a number from a user..

How do you access a list from another function in Python?

A Python function can return any object such as a list. To return a list, first create the list object within the function body, assign it to a variable your_list , and return it to the caller of the function using the keyword operation “ return your_list “.

Can you call a function within a list Python?

You can create the functions in the original scope, assign them to the array and then delete them from their original scope. Thus, you can indeed call them from the array but not as a local variable.

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