Dick Moores <rdm <at> rcblue.com> writes:
> So now that I know better, I'm trying to write the beginnings of a
> general setPrecision() function using format strings. However, it
> appears that a variable cannot be used instead of the ".2" in
>
> "%.2f" % 2.234234
<snip>
> How to do this?
You could use simple string concatenation:
>>> "%." + str(2) + 'f'
'%.2f'
>>> "%." + str(4) + 'f'
'%.4f'
Or use format strings to create other format strings, by escaping the '%' with
'%%'. E.g.:
>>> "%%.%df" % 2 # the '%%' will be changed to '%' in the result
'%.2f'
>>> "%%.%df" % 4
'%.4f'
>>> s1 = "%%.%df" % 2
>>> print s1, s1 % 3.41234
'%.2f', '3.41'
>>> s2 = "%%.%df" % 4
>>> print s2, s2 % 3.41234
'%.4f', '3.4123'
>>> ("%%.%df" % 2) % 3.23423
'3.23'
Yours,
Andrei
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