What does the \'u\' prefix mean in Python strings?

The meaning of the 'u' symbol in Python

Problem introduction

When generating a dictionary containing string key-value pairs, developers Notice that some values ​​are preceded by a "u" symbol. They want to know what the "u" symbol means and why it appears there.

Symbol meaning

The "u" symbol indicates that the string is a Unicode string. Unicode is a character encoding format that can represent a wider set of characters than the ASCII standard. In Python 2, a Unicode string needs to be marked with a "u" prefix to distinguish it from a standard ASCII string. In Python 3, strings are Unicode by default, so the "u" prefix is ​​not needed.

How to create Unicode strings

In Python 2, you can create Unicode strings in the following ways:

u'foo'
unicode('foo')

Why does the 'u' prefix appear

The "u" prefix is ​​used to represent characters beyond the ASCII character set, such as non-English characters or special symbols. It prevents strings from being mistaken for standard ASCII strings, which can cause encoding or display problems.

Unicode and non-Unicode strings

In Python 2, Unicode strings and non-Unicode strings are basically interoperable. However, in Python 3, Unicode strings and byte strings (bytes) are different types and need to be handled with care.

Summary

The "u" symbol represents Unicode strings in Python 2 and is used to represent characters outside the ASCII character set. Although it is no longer required in Python 3, understanding this distinction is important when dealing with string encodings.

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