Difference between Python print/format methods

Question

When combining a variable and a string to be printed in Python, there seem to be a number of ways to do the same thing;

test = \"Hello\"
print \"{} World\".f         


        

Answer 1

A little benchmark:

>>> a = lambda: "{} World".format("Hello")
>>> b = lambda: "Hello" + " World"
>>> c = lambda: "%s World" % "Hello"
>>> d = lambda: "".join(("Hello", " World"))
>>> a(), b(), c(), d()
('Hello World', 'Hello World', 'Hello World', 'Hello World')
>>> timeit.timeit(a)
0.7830071449279785
>>> timeit.timeit(b)
0.18782711029052734
>>> timeit.timeit(c)
0.18806695938110352
>>> timeit.timeit(d)
0.3966488838195801

Seems like b and c are fastest, after d, an surprisingly a is slowest.

But, if you don't do a lot of processing, it doesn't really matter which one to use, just it is better not to mix them.

I personally prefer "".join for just simple concentenations, and str.format for placing values, like "Hello, my name is {}.".format(name).

There was a rumor that % formatting will be deprecated and removed in Python 3, but it didn't.