Python dictionary comprehension example
dictionary, dictionary-comprehension, python
Solution
It's quite simple using the `enumerate` function:
>>> L = ['a', 'b', 'c', 'd']
>>> {letter: i for i,letter in enumerate(L, start=1)}
{'a': 1, 'c': 3, 'b': 2, 'd': 4}
Note that, if you wanted the inverse mapping, i.e. mapping `1` to `a`, `2` to `b` etc, you could simply do:
>>> dict(enumerate(L, start=1))
{1: 'a', 2: 'b', 3: 'c', 4: 'd'}
Problem
I am trying to learn Python dictionary comprehension, and I think it is possible to do in one line what the following functions do. I wasn't able to make the `n+1` as in the first or avoid using `range()` as in the second. Is it possible to use a counter that automatically increments during the comprehension, as in `test1()`? ``` def test1(): l = ['a', 'b', 'c', 'd'] d = {} n = 1 for i in l: d[i] = n n = n + 1 return d def test2(): l = ['a', 'b', 'c', 'd'] d = {} for n in range(len(l)): d[l[n]] = n + 1 return d ```