Question

I would like to format some text to the protein data bank file format. Basically what I need to do is start the text in specific columns. Right now I’m doing the formatting using ljust and rjust but I feel like there should be some magic function that I could use give a word and in what column it should start.

Any help would be greatly appreciated. Thanks

If my Statckoverflow searching failed, please point me in that direction.

Answer 1

Here is an example of how one might format a “Coordinate Record Description” using str.format:

CRD='{r:<6}{a:>9.3f}{b:>9.3f}{c:>9.3f}{alpha:7.2f}{beta:7.2f}{gamma:7.2f} {sp:<11}{z:>4}'

data=dict(r='CRYST1',a=117,b=15.0,c=39,alpha=90,beta=90,gamma=90,sp='P 21 21 21',z=8)
print(CRD.format(**data))

# CRYST1  117.000   15.000   39.000  90.00  90.00  90.00 P 21 21 21    8

The format specifier CRD is interpreted this way:

{r:<6} tells format to string-interpolate the value of str(r), left justified, with width=6.

{a:>9.3f} tells format to string-interpolate the float value of a, right justified, with total width 9 and 3 digits after the decimal point.

The complete description of how the format specified works is given here.