How do you ignore a slash in python?

This one is a bit tricky I think.

if I have:

a = "fwd"
b = "\fwd"

how can I ignore the "\" so something like

print(a in b)

can evaluate to True?

asked Apr 14, 2016 at 13:00

5

You don't have fwd in b. You have wd, preceded by ASCII codepoint 0C, the FORM FEED character. That's the value Python puts there when you use a \f escape sequence in a regular string literal.

Double the backslash if you want to include a backslash or use a raw string literal:

b = '\\fwd'
b = r'\fwd'

Now a in b works:

>>> 'fwd' in '\\fwd'
True
>>> 'fwd' in r'\fwd'
True

See the String literals documentation:

Unless an 'r' or 'R' prefix is present, escape sequences in strings are interpreted according to rules similar to those used by Standard C. The recognized escape sequences are:

[...]

\f ASCII Formfeed (FF)

jfs

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answered Apr 14, 2016 at 13:05

Martijn PietersMartijn Pieters

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One way of doing it using raw strings:

>>> a = "fwd"
>>> b = "\fwd"
>>> a in b
False
>>> a = r"fwd"
>>> b = r"\fwd"
>>> a in b
True

The relevant docs

answered Apr 14, 2016 at 13:04

jDojDo

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You need to "escape" the backslash, as in:

b = '\\fwd'

Otherwise, it reads the single backslash + f as an ASCII character (a formfeed).

Here's an example.

>>> a='fwd'
>>> b='\fwd'
>>> c='\\fwd'
>>> a in b
False
>>> a in c
True

answered Apr 14, 2016 at 13:05

rajah9rajah9

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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

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

Did you find this tutorial helpful ?

How do you escape a slash in Python?

Learn More. In Python strings, the backslash "\" is a special character, also called the "escape" character. It is used in representing certain whitespace characters: "\t" is a tab, "\n" is a newline, and "\r" is a carriage return. Conversely, prefixing a special character with "\" turns it into an ordinary character.

How do you ignore a character in Python?

“python string ignore characters” Code Answer.
text = ['! kick', '/ban', '! k! ck'].
for s in text:.
print s[0]. translate(None, '!/') + s[1:].
output:.
k! ck..

How do you ignore a special character in a string in Python?

To insert characters that are illegal in a string, use an escape character. An escape character is a backslash \ followed by the character you want to insert.