python strange looking loop

Question

      char_rdic = list('helo')
      char_dic = {w:i for i ,w in enumerate(char_rdic)}

I'm not really sure what this code actually do. what does w and i represent in this code?

`w` are members of `char_rdic`, `i` will be index. `enumerate(iterable)` returns pairs of `index, iterable_member` as seen here https://docs.python.org/3/library/functions.html#enumerate — Tomasz Plaskota, Sep 02 '16 at 11:25
The strange looking loop is called a list comprehension, or dictionary comprehension in this case. — polku, Sep 02 '16 at 11:26
oh thx for the term! how to check the value with dictionary? — , Sep 02 '16 at 11:26
In the future, check from the docs first: https://docs.python.org/3/library/functions.html#enumerate — Ilja Everilä, Sep 02 '16 at 11:26

score 1 · Answer 1 · answered Sep 02 '16 at 11:28

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This is a dict comprehension. If you are familiar with list comprehension ([do_stuff(a) for a in iterable] construct), that works very much the same way, but it builds a dict.

See Create a dictionary with list comprehension in Python and https://docs.python.org/3.5/tutorial/datastructures.html#dictionaries for the official documentation

answered Sep 02 '16 at 11:28

Guillaume

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thank you for comment. I do not understand people who keep giving negative things. my native language is not english. and i'm new to programming and also 12 years old. i'm trying to learn. but people are so mean. – Sep 12 '16 at 01:35

score 0 · Answer 2 · answered Sep 02 '16 at 11:27

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This code creates char_dic dictionary with chars from 'helo' string as keys and their occurence indexes in given string. i is an index of w element in char_rdic list.

answered Sep 02 '16 at 11:27

Abdulafaja

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python strange looking loop

2 Answers2