Hướng dẫn dùng backslash python python

Summary: in this tutorial, you’ll learn about the Python backslash character as a part of a special sequence character or to escape characters in a string.

Introduction to the Python backslash

In Python, the backslash[\] is a special character. If you use the backslash in front of another character, it changes the meaning of that character.

For example, the t is a literal character. But if you use the backslash character in front of the letter t, it’ll become the tab character [\t].

Generally, the backslash has two main purposes.

First, the backslash character is a part of special character sequences such as the tab character \t or the new line character \n.

The following example prints a string that has a newline character:

print['Hello,\n World']
Code language: PHP [php]

Output:

Hello,
World

The \n is a single character, not two. For example:

s = '\n'
print[len[s]] # 1
Code language: PHP [php]

Second, the backslash [\] escape other special characters. For example, if you have a string that has a single quote inside a single-quoted string like the following string, you need to use the backslash to escape the single quote character:

s = '"Python\'s awesome" She said'
print[s]
Code language: PHP [php]

Output:

"Python's awesome" She said
Code language: JavaScript [javascript]

Backslash in f-strings

PEP-498 specifies that an f-string cannot contain a backslash character as a part of the expression inside the curly braces {}.

The following example will result in an error:

colors = ['red','green','blue']
s = f'The RGB colors are:\n {'\n'.join[colors]}'
print[s]
Code language: PHP [php]

Error:

SyntaxError: f-string expression part cannot include a backslash
Code language: JavaScript [javascript]

To fix this, you need to join the strings in the colors list before placing them in the curly braces:

colors = ['red','green','blue']
rgb = '\n'.join[colors]
s = f"The RGB colors are:\n{rgb}"
print[s]
Code language: PHP [php]

Output:

The RGB colors are:
red
green
blue

  

Backslash in raw strings

Raw strings treat the backslash character [\] as a literal character. The following example treats the backslash character \ as a literal character, not a special character:

s = r'\n'
print[s]
Code language: PHP [php]

Output:

\n

Summary

• Python backslash character [\] is a special character used as a part of special sequence such as \t and \n.
• Use the Python backslash [\] to escape other special characters in a string.
• F-strings cannot contains the backslash a part of expression inside the curly braces {}.
• Raw strings treat the backslash [\] as a literal character.

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