Python: Map VS For Loop

Map in Python :

• Map is used to compute a function for different values 'in a single line of code ' .
• It takes two arguments, first is function name, that is defined already and the other is list, tuple or any other iterables .
• It is a way of applying same function for multiple numbers .
• It generates a map object at a particular location .
• It works fast when we call an already defined function on the elements

•  map(functionname, iterable)

For more information, refer to: Python map() function

for loop in Python :

• We use a for loop to repeat a block of code for a fixed number of times.
• Used when no results are required.
• To perform sequential traversal.
• Loop from 0 to n runs n+1 times.

•  for var in iterable :
            statements 

  Note: Here, var is the name given to the the iterating variable, iterable can be replaced by range() function, and they can be of any data type. Statements are the step of actions to be performed.

For more information, refer to: Python For Loops

Example:

# function to square a given number
def squareNum (a) :
    return a * a


listt = [0, -1, 3, 4.5, 99, .08]

# using 'map' to call the function
# 'squareNum' for all the elements
# of 'listt'
x = map(squareNum, listt)

# map function returns a map
# object at this particular 
# location
print(x) 

# convert map to list
print(list(x)) 


# alternate way to square all
# elements of 'listt' using
# 'for loop'

for i in listt :
    square = i * i
    print(square)

Output:

<map object at 0x7fe413cf9b00>
[0, 1, 9, 20.25, 9801, 0.0064]
0
1
9
20.25
9801
0.0064

Map vs for loop

Comparing performance , map() wins! map() works way faster than for loop.

Using map():Using for loop:

for loop can be with no content, no such concept exist in map() function.

Example: Python

</p><pre><code class="language-python3 1==">

# we use the keyword 'pass'
# to simply get a for loop 
# with no content
for i in range (10) :
    pass
</code></pre><p></p><p dir="ltr"><span>There can be an </span><code><span>else</span></code><span> condition in </span><code><span>for</span></code><span> loop which only runs when no </span><code><span>break</span></code><span> statement is used. There is nothing like this in </span><code><span>map</span></code><span>.</span></p><p dir="ltr"><b><strong>Example : </strong></b><gfg-tabs data-run-ide="true" data-mode="light"><gfg-tab slot="tab">Python

# for loop with else condition

for i in range(10) :
    print(i)
else : 
    print("Finished !")

0
1
2
3
4
5
6
7
8
9
Finished !

for loop can exit before too. We can do that using break statement. Exiting before expected is not possible in map.

map generates a map object, for loop does not return anything.

syntax of map and for loop are completely different.

for loop is for executing the same block of code for a fixed number of times, the map also does that but in a single line of code.

Let us see the differences in a tabular form -: