Python .format - error

Question

Hi,

I'm trying to get the following to work in a Python interpreter, however it gives me an error and I cannot seem to find where my mistake is? (I'm a python newbie)

>>> print 'THe value of PI is approx {}.'.format(math.pi)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
AttributeError: 'str' object has no attribute 'format'

Any ideas?

Answer 1

This works:

>>> print "The value of PI is approx {'%s'}." % format(math.pi)
The value of PI is approx {'3.14159265359'}.

So does this:

>>> print "The value of PI is approx '%f'"  % math.pi
The value of PI is approx '3.141593'

Answer 2

You may use Python version < 2.6, version >= 2.6 support {0}, version >= 2.7 support {} format.

Answer 3

You're using a too old version of python that does not support this string formatting method. On Python 2.6 this is the result (with a small correction):

>>> print 'THe value of PI is approx {0}.'.format(math.pi)
THe value of PI is approx 3.14159265359.

This method is the new way of string formatting (PEP 3101) and is supposed to replace the old way (with the %). I'm still used to the old way but in the long run I'll probably switch to the new way.