String formatting in Python

Question

I want to do something like String.Format(\"[{0}, {1}, {2}]\", 1, 2, 3) which returns:

[1, 2, 3]

How do I do this in Python?

Answer 1

You can do it three ways:

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Use Python's automatic pretty printing:

print [1, 2, 3]   # Prints [1, 2, 3]

Showing the same thing with a variable:

numberList = [1, 2]
numberList.append(3)
print numberList   # Prints [1, 2, 3]

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Use 'classic' string substitutions (ala C's printf). Note the different meanings here of % as the string-format specifier, and the % to apply the list (actually a tuple) to the formatting string. (And note the % is used as the modulo(remainder) operator for arithmetic expressions.)

print "[%i, %i, %i]" % (1, 2, 3)

Note if we use our pre-defined variable, we'll need to turn it into a tuple to do this:

print "[%i, %i, %i]" % tuple(numberList)

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Use Python 3 string formatting. This is still available in earlier versions (from 2.6), but is the 'new' way of doing it in Py 3. Note you can either use positional (ordinal) arguments, or named arguments (for the heck of it I've put them in reverse order.

print "[{0}, {1}, {2}]".format(1, 2, 3)

Note the names 'one' ,'two' and 'three' can be whatever makes sense.)

print "[{one}, {two}, {three}]".format(three=3, two=2, one=1)