The Python map () function executes a function on each element of a collection, such as a list or a set. The map () function accepts a function and an object to apply on which the function will work as arguments.
When working with a list of items in Python, you may want to perform a specific function on each of those items.
is where Python's built-in map () function comes in. Python's map function executes a function on all elements of an iterable object, such as a list, and returns the map of the objects .
In this tutorial, using a series of examples, we discuss how to use the map () function in python.
iterative objects are elements that contain a countable number of values and that can be traversed. Lists, dictionaries, tuples, and sets are all iterable in Python because they can contain multiple values and can be traversed.
Let's say you have a list of student names you want to memorize. Instead of storing these extra names Python variables , you can declare an array to store the values:
students = [" Lucy "" Bill "" Graham "" Tommy "" Leslie "]
students variable contains a list, which is an iterable object. This means that we can traverse the items in the list. function
The map () passes each element in a list and performs a function on each element. map () is built in python. This means you don't need to import any libraries to use the map () method
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Python card () is a higher order function that can be used to apply a specific function to multiple elements in an iterable object. The syntax for Python map () function is as follows:
map (function , iterable)
The first argument that the map () function accepts is the function. strong> This is the function that will be performed on each element of the iterables. iterable is the object that will be matched, such as a list, tuple, dictionary, or set
Suppose you are an administrator of a school who has been assigned the task of creating a complete list of students.
We decide to print a list of student names with each student's class class listed next to their name. This will avoid confusion if two students from two different classes have the same name.
This is a perfect application of the function. we have an iterable that we want to perform a function. the function will merge a student's name with the grade they are. Here is a program that could be used to merge student names with their own Python map class () level:
def mergeNamesAndGrades (name): return name + "First grade" students = ["Lucy " "Bill" "Graham" "Tommy" "Leslie"] student_r Oster = card (mergeNamesAndGrades, students)
In the first two lines, we declare a Python function called mergeNamesAndGrades. This function combines with the Grade 1 name of each student.
So on the next line we define the list of students in our school. There are five students on our list.
map () function is applied to the content of the student_roster Python variable . The map () function takes two arguments: the function (in this case, mergeNamesAndGra des) and the iterable object (students).
The map () method applies the mergeNamesAndGrades () function to every student in our list.
However, our program is not yet complete. map () function returns a mapped object , not our full list. If we print our student_roster variable at this time, our code will return a matched object like this:
This output was generated because the map () function returns its own custom object, rather than a list. So if we want to print the list of student names, we need to convert our student_roster variable into a list. Here is the code we can use to perform this action:
print (list (student_roster))
Our code returns the list Python :
[Lucy first year ',' the draft law in the first year, '' Graham first year ',' Tommy first year ',' first year Leslie ']
Let's see another example. Let's say we want to convert each student's name and grade to upper case for our student list. We could use the following code to change the cases of student names and grades:
def changeCase (name): return name.upper () student_roster = ['Lucy First grade', 'Bill First grade', 'Graham First grade', 'Tommy First grade', 'Leslie First grade'] = final_student_roster card (changeCase, student_roster) print (list (final_student_roster))
Our code returns a list that we can iterate over:
['LUCY first year', 'FIRST BILL GRADE', 'GRAHAM first year', 'TOMMY first year', 'LESLIE first year']
In this example, we have defined a function called changeCase. This function changed the name of each student to upper case. We used the Python upper () function to convert the case of each name
Our program used the map () function to call changeCase () on each object in our iterables student_roster. Finally, our program returned the revised list of student names in capital letters. Function
The Python map () function can be used with lambda function to render our more efficient code. in the previous examples we declared a new function to modify our iterables in some way.
But if we want to perform an action on an iterable object only once, there is no need to declare a new function. Instead of this, we can use lambda function Python, which is a small anonymous function