How to Properly Escape Percent Signs in Python String Formatting?

Selective Escaping of Percent Signs in Python Strings

In Python, the percent sign (%) is used as a placeholder for formatting values into strings. However, in some cases, you may want to selectively escape the percent sign to display it as a literal character instead. This can be achieved by adding an extra percent sign before the one you wish to escape.

Example:

Consider the following code:

test = "have it break."
selectiveEscape = "Print percent % in sentence and not %s" % test
print(selectiveEscape)

The above code is expected to produce the output:

Print percent % in sentence and not have it break.

However, the actual output will be an error:

TypeError: %d format: a number is required, not str

This error occurs because Python interprets the first percent sign as the start of a formatting placeholder, but the value it finds is a string, not a number.

Solution:

To escape the percent sign and display it as a literal character, an additional percent sign must be added before the one you wish to escape. Here's the corrected code:

selectiveEscape = "Print percent %% in sentence and not %s" % test
print(selectiveEscape)

The output of the corrected code will now be:

Print percent % in sentence and not have it break.

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