Python way of printing: with 'format' or percent form?
Question:
In Python there seem to be two different ways of generating formatted output:
user = "Alex"
number = 38746
print("%s asked %d questions on stackoverflow.com" % (user, number))
print("{0} asked {1} questions on stackoverflow.com".format(user, number))
Is there one way to be preferred over the other? Are they equivalent, what is the difference? What form should be used, especially for Python3?
Answers:
Use the format method, especially if you’re concerned about Python 3 and the future. From the documentation:
The formatting operations described here are modelled on C’s printf()
syntax. They only support formatting of certain builtin types. The
use of a binary operator means that care may be needed in order to
format tuples and dictionaries correctly. As the new
:ref:string-formatting syntax is more flexible and handles tuples and
dictionaries naturally, it is recommended for new code. However, there
are no current plans to deprecate printf-style formatting.
The docs say that the format method is preferred for new code. There are currently no plans to remove % formatting, though.
.format was introduced in Python2.6
If you need backward compatibility with earlier Python, you should use %
For Python3 and newer you should use .format for sure
.format is more powerful than %. Porting % to .format is easy but the other way round can be non trivial
You can use both .No one said % formatting expression is deprecated.However,as stated before the format method call is a tad more powerful.
Also note that the % expressions are bit more concise and easier to code.Try them and see what suits you best
In Python there seem to be two different ways of generating formatted output:
user = "Alex"
number = 38746
print("%s asked %d questions on stackoverflow.com" % (user, number))
print("{0} asked {1} questions on stackoverflow.com".format(user, number))
Is there one way to be preferred over the other? Are they equivalent, what is the difference? What form should be used, especially for Python3?
Use the format method, especially if you’re concerned about Python 3 and the future. From the documentation:
The formatting operations described here are modelled on C’s
printf()
syntax. They only support formatting of certain builtin types. The
use of a binary operator means that care may be needed in order to
format tuples and dictionaries correctly. As the new
:ref:string-formattingsyntax is more flexible and handles tuples and
dictionaries naturally, it is recommended for new code. However, there
are no current plans to deprecateprintf-style formatting.
The docs say that the format method is preferred for new code. There are currently no plans to remove % formatting, though.
.format was introduced in Python2.6
If you need backward compatibility with earlier Python, you should use %
For Python3 and newer you should use .format for sure
.format is more powerful than %. Porting % to .format is easy but the other way round can be non trivial
You can use both .No one said % formatting expression is deprecated.However,as stated before the format method call is a tad more powerful.
Also note that the % expressions are bit more concise and easier to code.Try them and see what suits you best