如何在Python中的括号内附加一个字符？

Question

I have the following input:

[ [ 'A(x)|B(x,y)|C(z)'],['A(x,y)|B(John,y)|C(z)' ] ]

I want the following output

[ [ A(x1)|B(x1,y1)|C(z1)'],['A(x2,y2)|B(John,y2)|C(z2)' ] ] 

If I have a list of lists as the input, how can I append a counter initialized to one successively in this manner?

Answer 1

Since it's a list of lists, you have to use list comprehension, enumerate , regex.

>>> import re
>>> x = [ [ 'A(x)|B(x,y)|C(z)'],['A(x,y)|B(John,y)|C(z)' ] ]
>>> [[re.sub(r'([xyz])', r'\g<1>{}'.format(i+1), k) for k in j] for i,j in enumerate(x)]
[['A(x1)|B(x1,y1)|C(z1)'], ['A(x2,y2)|B(John,y2)|C(z2)']]
------
>>> x = [ [ 'A(x)|B(x,y)|C(z)', 'B(x,y)'],['A(x,y)|B(John,y)|C(z)' ], ['A|B'], ['A(x,y)|B(John,y)|C(z)'] ]
>>> [[re.sub(r'([xyz])', r'\g<1>{}'.format(i), k) for k in j] for i,j in enumerate(x, 1)]
[['A(x1)|B(x1,y1)|C(z1)', 'B(x1,y1)'], ['A(x2,y2)|B(John,y2)|C(z2)'], ['A|B'], ['A(x4,y4)|B(John,y4)|C(z4)']]

Iterate over the main list , then iterate over sublist and then match and replace (append the index number next to x or y or z) each string present inside the sublist.

Answer 2

Python code

I'd personally use regex for this. re.sub substitutes a string for another string (that contains regex markup, like \\g<1> ).

re.sub("(?<!\w)([xyz])",r"\g<1>2",before)

Making your full code:

import re

before = "[ [ 'A(x)|B(x,y)|C(z)'],['A(x,y)|B(John,y)|C(z)' ] ]"
print(re.sub("(?<!\w)([xyz])",r"\g<1>2",before))

Regex explanation

(?<!\w)([xyz])

We are doing a negative look behind to make sure that it isn't part of a word, (?<!\\w) . Then we check for our desired variable names, ([xyz]) . If it follows this pattern, then we replace it with:

\g<1>2

I used \\g<1> instead of \\1 because Python won't interpret \\12 as we want. It will view it as regex group 12, instead of regex group 1 then the number 2.

Regex101 is a great tool for understanding regex's. Click the link to view how it works.