Capitalize specific indices of string using awk or python

Question

I have an input file where each line contains 99 lowercase letters,

bccdddcdccddddddabcdabcabdbacbdcaaccbbcabacbccabcacbcdcccbdbacdcbbcbcbcccacadaaccababadbcbaabbbccbb 
bccdddcdcddddcddabcdabcabdbacbddaacdbbcabacbcdbbcacbcccccbdbacdbbbcbcbacbacacaacccbabadbcbaabbbccbb 
bccdddcdcddddccdabcdabcabdbacbddaaddbbcabacbcdbbcacbcccccbdbacdbbbcbcbaccacadaaccbbabadbccacbbbccbb 
bccdddcdccdddccdabcdabcdbdbacbdcaaddcbcabacbccabcacbcdcccbdbacdbbbcbcbbccacadaaccbbabadbccaaabbccbb 

I have a list of positions, for example p = [10, 14, 89, 99].

I'd like to capitalize the letters at these positions in my input file.

Desired output:

bccdddcdcCdddDddabcdabcabdbacbdcaaccbbcabacbccabcacbcdcccbdbacdcbbcbcbcccacadaaccababadbCbaabbbccbB 
bccdddcdcDdddCddabcdabcabdbacbddaacdbbcabacbcdbbcacbcccccbdbacdbbbcbcbacbacacaacccbabadbCbaabbccbB 
bccdddcdcDdddCcdabcdabcabdbacbddaaddbbcabacbcdbbcacbcccccbdbacdbbbcbcbaccacadaaccbbabadbCcacbbccbbB 
bccdddcdcCdddCcdabcdabcdbdbacbdcaaddcbcabacbccabcacbcdcccbdbacdbbbcbcbbccacadaaccbbabadbCcaaabbccbB 

I'm using this awk command:

awk -vFS= -vOFS= '{$10=toupper($10)}1' input > output

But I'm not sure how to loop this over all the positions.

Answer 1

You can use a generator expression with .upper() and enumerate() to capitalize only the specified indices:

p = [10, 14, 89, 99] # or use set([10, 14, 89, 99]) for faster lookup
with open('in.txt') as file:
    for line in file:
        line = line.rstrip()
        result = ''.join(c.upper() if i + 1 in p else c for i, c in enumerate(line))
        print(result)

This outputs:

bccdddcdcCdddDddabcdabcabdbacbdcaaccbbcabacbccabcacbcdcccbdbacdcbbcbcbcccacadaaccababadbCbaabbbccbB
bccdddcdcDdddCddabcdabcabdbacbddaacdbbcabacbcdbbcacbcccccbdbacdbbbcbcbacbacacaacccbabadbCbaabbbccbB
bccdddcdcDdddCcdabcdabcabdbacbddaaddbbcabacbcdbbcacbcccccbdbacdbbbcbcbaccacadaaccbbabadbCcacbbbccbB
bccdddcdcCdddCcdabcdabcdbdbacbdcaaddcbcabacbccabcacbcdcccbdbacdbbbcbcbbccacadaaccbbabadbCcaaabbccbB