PYTHON — How To Convert List elements to Dictionary.

 l = ["a", "b", "c", "d", "e"]

dict()

dict(one=1, two=2)
dict({'one': 1, 'two': 2})
dict(zip(('one', 'two'), (1, 2)))
dict([['two', 2], ['one', 1]])
l = [["a", "b"], ["c", "d"], ["e",]]

slice notation

>>> l[::2]
['a', 'c', 'e']
>>> l[1::2]
['b', 'd']
>>> zip(['a', 'c', 'e'], ['b', 'd'])
[('a', 'b'), ('c', 'd')]
>>> dict(zip(l[::2], l[1::2]))
{'a': 'b', 'c': 'd'}
>>> a = [1, 2, 3]
>>> b = a
>>> b
[1, 2, 3]
>>> b is a
True
>>> b = a[:]
>>> b
[1, 2, 3]
>>> b is a
False

grouper recipe

*[iter(l)]*2

zip for shortest

>>> l*2
['a', 'b', 'c', 'd', 'e', 'a', 'b', 'c', 'd', 'e']
>>> [l]*2
[['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'e']]
>>> [iter(l)]*2
[<listiterator object at 0x100486450>, <listiterator object at 0x100486450>]
>>> zip([iter(l)]*2)
[(<listiterator object at 0x1004865d0>,),(<listiterator object at 0x1004865d0>,)]
>>> zip(*[iter(l)]*2)
[('a', 'b'), ('c', 'd')]
>>> dict(zip(*[iter(l)]*2))
{'a': 'b', 'c': 'd'}
>>> it = iter(l)     
>>> dict(zip(it, it))
{'a': 'b', 'c': 'd'}
>>> if len(l) % 2:
... l.append("")
>>> l
['a', 'b', 'c', 'd', 'e', '']
>>> dict(zip(*[iter(l)]*2))
{'a': 'b', 'c': 'd', 'e': ''}

map for longest

>>> l = ["a", "b", "c", "d", "e"]
>>> l
['a', 'b', 'c', 'd', 'e']
>>> dict(map(None, *[iter(l)]*2))
{'a': 'b', 'c': 'd', 'e': None}
$ time python -c 'dict(map(None, *[iter(range(10000000))]*2))'
real 0m3.755s
user 0m2.815s
sys 0m0.869s
$ time python -c 'from itertools import izip_longest; dict(izip_longest(*[iter(range(10000000))]*2, fillvalue=None))'
real 0m2.102s
user 0m1.451s
sys 0m0.539s
$ time python -c 'dict(map(None, *[iter(range(100))]*2))'
real 0m0.046s
user 0m0.029s
sys 0m0.015s
$ time python -c 'from itertools import izip_longest; dict(izip_longest(*[iter(range(100))]*2, fillvalue=None))'
real 0m0.067s
user 0m0.042s
sys 0m0.021s
$ time python -c 'dict(map(None, *[iter(range(100000))]*2))'
real 0m0.074s
user 0m0.050s
sys 0m0.022s
$ time python -c 'from itertools import izip_longest; dict(izip_longest(*[iter(range(100000))]*2, fillvalue=None))'
real 0m0.075s
user 0m0.047s
sys 0m0.024s

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R&Design for products, Passionate DevOps at my own will & intermediate coder My other skills shell scripting,powershell,cloud AWS/AZURE,kubernetes & Automation

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Ankur Jain

Ankur Jain

R&Design for products, Passionate DevOps at my own will & intermediate coder My other skills shell scripting,powershell,cloud AWS/AZURE,kubernetes & Automation

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