how two join and arrange two files together

[Peter Otten]

amrita at iisermohali.ac.in wrote:

[please keep the correspondence on the mailing list/newsgroup]

> It is working sir, but my datas are on file when i replaced StringIO("")
> with open("filename.txt") then it is not printing the result properly,
> like in one file i have data like:---
> 33 ALA H = 7.57 N = 121.52 CA = 55.58 HA = 3.89 C = 179.24
> 38 ALA H = 8.29 N = 120.62 CA = 54.33 HA = 4.04 C = 178.95
> 8 ALA H = 7.85 N = 123.95 CA = 54.67 HA = 2.98  C = 179.39
> 15 ALA H = 8.05 N = 119.31 CA = 52.18 HA = 4.52 C = 177.18
> 21 ALA H = 7.66 N = 123.58 CA = 54.33 HA = 4.05 C = 179.35
> 23 ALA H = 8.78 N = 120.16 CA = 55.84 HA = 4.14 C = 179.93
> in other:---
> 8 ALA  helix (helix_alpha, helix1)
> 21 ALA  helix (helix_alpha, helix2)
> 23 ALA  helix (helix_alpha, helix2)
> 33 ALA  helix (helix_alpha, helix3)
> 38 ALA  helix (helix_alpha, helix3)
> 49 ALA  bend
> and it is giving the result:-
> 15 ALA H = 8.05 N = 119.31 CA = 52.18 HA = 4.52 C = 177.18|
> 23 ALA H = 8.78 N = 120.16 CA = 55.84 HA = 4.14 C = 179.93|23 ALA  helix
> (helix_alpha, helix2)
> 38 ALA H = 8.29 N = 120.62 CA = 54.33 HA = 4.04 C = 178.95|38 ALA  helix
> (helix_alpha, helix3)
>           |49 ALA  bend
> 8 ALA H = 7.85 N = 123.95 CA = 54.67 HA = 2.98  C = 179.39|8 ALA  helix
> (helix_alpha, helix1)
> it is not printing the result for 33 and 21.

Hint: you have to adapt the key() function from

    def key(line):
        return line[:1]

to something that returns the same key for lines in the two files that 
belong together, and different keys for lines that don't.

Peter