Python map() Function
Returns an interator that applies the specified function to every item in the iterable (usually a collection), and yields the results.
Syntax
Python
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map(func, iterable1, iterable2, ...)
Parameters
Parameter | Description |
---|---|
iterable1, iterable2, ... |
Required. The iterable or iterables which will have the func applied to each item within. |
func |
Required. The function that will be applied to each item in each iterator |
A common use case for
the map()
function is to return values in the iterable that are
"mapped" to new values. It is also typical to apply the list()
function to evaluate the return of the map()
function into a list.
Example
Python
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def times5(n): return n * 5 nums = [1, 2, 3] mappedNums = list(map(times5, nums)) print(mappedNums)
Output
[5, 10, 15]
Notes
The map()
function is often used with lambda
expressions.
Example
Python
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times10 = list(map(lambda x: x * 10, [1, 2, 3])) print(times10)
Output:
[10, 20, 30]
The map()
function can also be used with more than one iterable. This is
useful when mapping two or more iterables into a single collection of values.
In this case, if the iterables are of different lengths, the mapping function
stops when the shortest list is exhausted.
Example
Python
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nums1 = [1, 2, 3] nums2 = [10, 20, 30, 40] added = list(map(add, nums1, nums2)) print(added)
Output:
[11, 22, 33]