"map" in python

[Humble]

map accepts 2 arguments .. first arg is the function and second arg is the sequence .. so it got below form:

map(func, seq)

Now the sequence is not restricted to “1”, it can have more than 1 sequence.. how-ever those have to be of the same length..

In that case, the function will be applied to each index in all the sequences..

for ex:

>>>> l = [1,10,100]
>>> m = [2,20,200]
>>> map(lambda x,y: x/y, l,m)
[0, 0, 0]
>>> map(lambda x,y: x%y, l,m)
[1, 10, 100]
>>> map(lambda x,y: x*y, l,m)
[2, 200, 20000]
>>>



map() is well used with the combination of lambda functions as you can see in the above example.

In short , To apply an operation to each item in a sequence/list and to collect the result, the map() will be really useful..

map call is similar to list comprehension..

[Humble]

In python3 or above, the “return” of map() will be shown as an object: You need to input that to list to see the desired result..

Code:

>>> l = [1,10,100]
>>> m = [2,20,200]
>>> map(lambda x,y: x*y, l,m)
<map object at 0x7f7753fcb790>
>>> list(map(lambda x,y: x*y, l,m))
[2, 200, 20000]
>>>

[Humble]

Also, if first arg (ie: func ) is “none”, the map() returns the elements of iteratable object as a tuple…

[Author]

Posts