Why are python strings left aligned in format with specified width?

Question

While thinking of a way to pretty print table header i found that integers are right aligned by default, but strings are left aligned.

For example:

>>> for i in (1,'x',0.0):
...     print("{0:5}".format(i))
... 
    1
x    
  0.0

This is easily fixed by setting alignment explicitly, but i wonder why is this so?

EDIT:

I am not looking for a way to align strings, it is easy:

>>> for i in (1,'x',0.0):
...     print("{0:>5}".format(i))
... 
    1
    x
  0.0

I just thought that all objects would be aligned the same way by deafult and i'm asking why is it not so.

I think it's just considered natural. It's the standard formatting in most spreadsheet programs, too. — Sven Marnach
– Sven Marnach, Commented Nov 5, 2011 at 9:55

Srikar Appalaraju · Accepted Answer · 2011-11-05 10:02:25Z

1

Was going through the documentation. No clue what so ever for this.

Just a wild guess - We read text left-right so strings

answered Nov 5, 2011 at 10:02

Srikar Appalaraju

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1 Comment

Blin Over a year ago

And we read numbers some other way? I don't think that this is related.

Paolo · Accepted Answer · 2011-11-10 22:43:55Z

1

Probably you are looking for something like this

print ( "%5s" % ('x',) )
print ( "%5d" % (245,) )

which outputs

    x
  245

For the question 'why' I think an answer is that when you read some data in column you actually expect string to be left aligned

a
ab
abc

and not

   a
  ab
 abc

Also text in books is left aligned. For number most natural formatting is right aligned

  7
 45
156

Which for istance is the way of arranging numbers for sum, subtraction and multiplication. Python choice actually reflects typographic conventions. Mixing text and numbers in a table may be considered a special case.

edited Nov 10, 2011 at 22:43

answered Nov 5, 2011 at 10:05

Paolo

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Comments

9000 · Accepted Answer · 2011-11-10 14:47:53Z

0

Python 3 syntax (available in 2.6, too)

>>> print("{foo:>5s}\n{bar:>5d}".format(foo="a", bar=100))
    a
  100

Read the format spec. The alignment specifier here is the >.

answered Nov 10, 2011 at 14:47

9000

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