Getting indices of list based on a second list

Question

I have a list a which contains all the possible values in list b

a = ['foo', 'bar', 'baz']

and

b = ['baz', 'baz', 'foo', 'foo', 'foo', 'bar', 'foo', 'baz']

I'd like to return a list c which has the number of elements found in b where each element is the index of a in for which the value of b can be found.

Example

c = [2, 2, 0, 0, 0, 1, 0, 2]

Did you try anything for it?, also if the value cannot be found, what should be in `c`? — Devesh Kumar Singh, Jul 04 '19 at 16:17
I can find a particular value if I do something like `[i for i, x in enumerate(a) if x == "foo"]` but not all values — agf1997, Jul 04 '19 at 16:19

score 1 · Accepted Answer · answered Jul 04 '19 at 16:19

1

One-liner:

c = [a.index(x) for x in b]

answered Jul 04 '19 at 16:19

Matias Cicero

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score 1 · Answer 2 · answered Jul 04 '19 at 16:19

1

>>> a = ['foo', 'bar', 'baz']
>>> b = ['baz', 'baz', 'foo', 'foo', 'foo', 'bar', 'foo', 'baz']
>>> [a.index(i) for i in b]
[2, 2, 0, 0, 0, 1, 0, 2]

answered Jul 04 '19 at 16:19

Saket Mittal

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Getting indices of list based on a second list

2 Answers2