Map Function

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Syntax

  • map(function, iterable[, *additional_iterables])
  • future_builtins.map(function, iterable[, *additional_iterables])
  • itertools.imap(function, iterable[, *additional_iterables])

Parameters

ParameterDetails
functionfunction for mapping (must take as many parameters as there are iterables) (positional-only)
iterablethe function is applied to each element of the iterable (positional-only)
*additional_iterablessee iterable, but as many as you like (optional, positional-only)

Remarks

Everything that can be done with map can also be done with comprehensions:

list(map(abs, [-1,-2,-3]))    # [1, 2, 3]
[abs(i) for i in [-1,-2,-3]]  # [1, 2, 3]

Though you would need zip if you have multiple iterables:

import operator
alist = [1,2,3]
list(map(operator.add, alist, alist))  # [2, 4, 6]
[i + j for i, j in zip(alist, alist)]  # [2, 4, 6]

List comprehensions are efficient and can be faster than map in many cases, so test the times of both approaches if speed is important for you.

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Sunday, January 1, 2017
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