If I want to make my formatted string dynamically adjustable, I can change the following code from

print '%20s : %20s' % ("Python", "Very Good")

to

width = 20 print ('%' + str(width) + 's : %' + str(width) + 's') % ("Python", "Very Good")

However, it seems that string concatenation is cumbersome here. Any other way to simplify things?

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5 Answers

You can do this using the str.format() method.

>>> width = 20 >>> print("{:>{width}} : {:>{width}}".format("Python", "Very Good", width=width)) Python : Very Good

Starting from Python 3.6 you can use f-string to do this:

In [579]: lang = 'Python' In [580]: adj = 'Very Good' In [581]: width = 20 In [582]: f'{lang:>{width}}: {adj:>{width}}' Out[582]: ' Python: Very Good'
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You can fetch the padding value from the argument list:

print '%*s : %*s' % (20, "Python", 20, "Very Good")

You can even insert the padding values dynamically:

width = 20 args = ("Python", "Very Good") padded_args = zip([width] * len(args), args) # Flatten the padded argument list. print "%*s : %*s" % tuple([item for list in padded_args for item in list])
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For those who want to do the same thing with python 3.6+ and f-Strings this is the solution.

width = 20 py, vg = "Python", "Very Good" print(f"{py:>{width}s} : {vg:>{width}s}")
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print '%*s : %*s' % (width, 'Python', width, 'Very Good')
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If you don't want to specify the widths at the same time, you can prepare a format string ahead of time, like you were doing - but with another substitution. We use %% to escape actual % signs in a string. We want to end up with %20s in our format string when the width is 20, so we use %%%ds and supply the width variable to substitute in there. The first two % signs become a literal %, and then %d is substituted with the variable.

Thus:

format_template = '%%%ds : %%%ds' # later: width = 20 formatter = format_template % (width, width) # even later: print formatter % ('Python', 'Very Good')
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