Question

Let’s say I have a list

l = ['michael','michael','alice','carter']

I want to map it to the following:

k = [1,1,2,3]

Where michael corresponds to 1, alice corresponds to 2 etc. Is there a function in Python to do this easily?

Answer 1

Have a look at ord, which gives the unicode number for a given character:

>>> letters = ['a','b','c','d','e','f','g']
>>> [ord(x) for x in letters]
[97, 98, 99, 100, 101, 102, 103]

So you could do ord(x)-96 to convert a-z to 1-26 (careful about upper case, etc).

l = ['a','b','a','c']
k = [ord(x)-96 for x in l] # [1,2,1,3]

Again, careful about upper case and non-alphabet characters.