How to fix “ DeprecationWarning: invalid escape sequence” in Python?
I'm getting lots of warnings like this in Python:
DeprecationWarning: invalid escape sequence A
orcid_regex = 'A[0-9]{4}-[0-9]{4}-[0-9]{4}-[0-9]{3}[0-9X]Z'
DeprecationWarning: invalid escape sequence /
AUTH_TOKEN_PATH_PATTERN = '^/api/groups'
DeprecationWarning: invalid escape sequence
"""
DeprecationWarning: invalid escape sequence .
DOI_PATTERN = re.compile('(https?://(dx.)?doi.org/)?10.[0-9]{4,}[.0-9]*/.*')
<unknown>:20: DeprecationWarning: invalid escape sequence (
<unknown>:21: DeprecationWarning: invalid escape sequence (
What do they mean? And how can I fix them?
python python-3.x python-3.6
asked Sep 14 at 16:30
Sean Hammond
2,5711025
add a comment |
I'm getting lots of warnings like this in Python:
DeprecationWarning: invalid escape sequence A
orcid_regex = 'A[0-9]{4}-[0-9]{4}-[0-9]{4}-[0-9]{3}[0-9X]Z'
DeprecationWarning: invalid escape sequence /
AUTH_TOKEN_PATH_PATTERN = '^/api/groups'
DeprecationWarning: invalid escape sequence
"""
DeprecationWarning: invalid escape sequence .
DOI_PATTERN = re.compile('(https?://(dx.)?doi.org/)?10.[0-9]{4,}[.0-9]*/.*')
<unknown>:20: DeprecationWarning: invalid escape sequence (
<unknown>:21: DeprecationWarning: invalid escape sequence (
What do they mean? And how can I fix them?
python python-3.x python-3.6
asked Sep 14 at 16:30
Sean Hammond
2,5711025
add a comment |
I'm getting lots of warnings like this in Python:
DeprecationWarning: invalid escape sequence A
orcid_regex = 'A[0-9]{4}-[0-9]{4}-[0-9]{4}-[0-9]{3}[0-9X]Z'
DeprecationWarning: invalid escape sequence /
AUTH_TOKEN_PATH_PATTERN = '^/api/groups'
DeprecationWarning: invalid escape sequence
"""
DeprecationWarning: invalid escape sequence .
DOI_PATTERN = re.compile('(https?://(dx.)?doi.org/)?10.[0-9]{4,}[.0-9]*/.*')
<unknown>:20: DeprecationWarning: invalid escape sequence (
<unknown>:21: DeprecationWarning: invalid escape sequence (
What do they mean? And how can I fix them?
python python-3.x python-3.6
asked Sep 14 at 16:30
Sean Hammond
2,5711025
I'm getting lots of warnings like this in Python:
DeprecationWarning: invalid escape sequence A
orcid_regex = 'A[0-9]{4}-[0-9]{4}-[0-9]{4}-[0-9]{3}[0-9X]Z'
DeprecationWarning: invalid escape sequence /
AUTH_TOKEN_PATH_PATTERN = '^/api/groups'
DeprecationWarning: invalid escape sequence
"""
DeprecationWarning: invalid escape sequence .
DOI_PATTERN = re.compile('(https?://(dx.)?doi.org/)?10.[0-9]{4,}[.0-9]*/.*')
<unknown>:20: DeprecationWarning: invalid escape sequence (
<unknown>:21: DeprecationWarning: invalid escape sequence (
What do they mean? And how can I fix them?
python python-3.x python-3.6
python python-3.x python-3.6
asked Sep 14 at 16:30
Sean Hammond
2,5711025
asked Sep 14 at 16:30
Sean Hammond
2,5711025
asked Sep 14 at 16:30
Sean Hammond
2,5711025
asked Sep 14 at 16:30
Sean Hammond
2,5711025
asked Sep 14 at 16:30
Sean Hammond
2,5711025
2,5711025
add a comment |
add a comment |
1 Answer
1
active
oldest
votes
is the escape character in Python string literals.
For example if you want to put a tab character in a string you would do:
>>> print("foo t bar")
foo bar
If you want to put a literal in a string you have to use \:
>>> print("foo \ bar")
foo bar
Or use a "raw string":
>>> print(r"foo bar")
foo bar
You can't just go putting backslashes in string literals whenever you want one. A backslash isn't valid when not followed by one of the valid escape sequences, and newer versions of Python print a deprecation warning. For example A isn't an escape sequence:
$ python3.6 -Wd -c '"A"'
<string>:1: DeprecationWarning: invalid escape sequence A
If your backslash sequence does accidentally match one of Python's escape sequences, but you didn't mean it to, that's even worse.
So you should always use raw strings or \.
It's important to remember that a string literal is still a string literal even if that string is intended to be used as a regular expression. Python's regular expression syntax supports lots of special sequences that begin with . For example A matches the start of a string. But A is not valid in a Python string literal! This is invalid:
my_regex = "Afoo"
Instead you should do this:
my_regex = r"Afoo"
Docstrings are another one to remember: docstrings are string literals too, and invalid sequences are invalid in docstrings too! Use raw strings (r"""...""") for docstrings if they contain 's.
answered Sep 14 at 16:30
Sean Hammond
2,5711025
add a comment |
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1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
is the escape character in Python string literals.
For example if you want to put a tab character in a string you would do:
>>> print("foo t bar")
foo bar
If you want to put a literal in a string you have to use \:
>>> print("foo \ bar")
foo bar
Or use a "raw string":
>>> print(r"foo bar")
foo bar
You can't just go putting backslashes in string literals whenever you want one. A backslash isn't valid when not followed by one of the valid escape sequences, and newer versions of Python print a deprecation warning. For example A isn't an escape sequence:
$ python3.6 -Wd -c '"A"'
<string>:1: DeprecationWarning: invalid escape sequence A
If your backslash sequence does accidentally match one of Python's escape sequences, but you didn't mean it to, that's even worse.
So you should always use raw strings or \.
It's important to remember that a string literal is still a string literal even if that string is intended to be used as a regular expression. Python's regular expression syntax supports lots of special sequences that begin with . For example A matches the start of a string. But A is not valid in a Python string literal! This is invalid:
my_regex = "Afoo"
Instead you should do this:
my_regex = r"Afoo"
Docstrings are another one to remember: docstrings are string literals too, and invalid sequences are invalid in docstrings too! Use raw strings (r"""...""") for docstrings if they contain 's.
answered Sep 14 at 16:30
Sean Hammond
2,5711025
add a comment |
is the escape character in Python string literals.
For example if you want to put a tab character in a string you would do:
>>> print("foo t bar")
foo bar
If you want to put a literal in a string you have to use \:
>>> print("foo \ bar")
foo bar
Or use a "raw string":
>>> print(r"foo bar")
foo bar
You can't just go putting backslashes in string literals whenever you want one. A backslash isn't valid when not followed by one of the valid escape sequences, and newer versions of Python print a deprecation warning. For example A isn't an escape sequence:
$ python3.6 -Wd -c '"A"'
<string>:1: DeprecationWarning: invalid escape sequence A
If your backslash sequence does accidentally match one of Python's escape sequences, but you didn't mean it to, that's even worse.
So you should always use raw strings or \.
It's important to remember that a string literal is still a string literal even if that string is intended to be used as a regular expression. Python's regular expression syntax supports lots of special sequences that begin with . For example A matches the start of a string. But A is not valid in a Python string literal! This is invalid:
my_regex = "Afoo"
Instead you should do this:
my_regex = r"Afoo"
Docstrings are another one to remember: docstrings are string literals too, and invalid sequences are invalid in docstrings too! Use raw strings (r"""...""") for docstrings if they contain 's.
answered Sep 14 at 16:30
Sean Hammond
2,5711025
add a comment |
is the escape character in Python string literals.
For example if you want to put a tab character in a string you would do:
>>> print("foo t bar")
foo bar
If you want to put a literal in a string you have to use \:
>>> print("foo \ bar")
foo bar
Or use a "raw string":
>>> print(r"foo bar")
foo bar
You can't just go putting backslashes in string literals whenever you want one. A backslash isn't valid when not followed by one of the valid escape sequences, and newer versions of Python print a deprecation warning. For example A isn't an escape sequence:
$ python3.6 -Wd -c '"A"'
<string>:1: DeprecationWarning: invalid escape sequence A
If your backslash sequence does accidentally match one of Python's escape sequences, but you didn't mean it to, that's even worse.
So you should always use raw strings or \.
It's important to remember that a string literal is still a string literal even if that string is intended to be used as a regular expression. Python's regular expression syntax supports lots of special sequences that begin with . For example A matches the start of a string. But A is not valid in a Python string literal! This is invalid:
my_regex = "Afoo"
Instead you should do this:
my_regex = r"Afoo"
Docstrings are another one to remember: docstrings are string literals too, and invalid sequences are invalid in docstrings too! Use raw strings (r"""...""") for docstrings if they contain 's.
answered Sep 14 at 16:30
Sean Hammond
2,5711025
is the escape character in Python string literals.
For example if you want to put a tab character in a string you would do:
>>> print("foo t bar")
foo bar
If you want to put a literal in a string you have to use \:
>>> print("foo \ bar")
foo bar
Or use a "raw string":
>>> print(r"foo bar")
foo bar
You can't just go putting backslashes in string literals whenever you want one. A backslash isn't valid when not followed by one of the valid escape sequences, and newer versions of Python print a deprecation warning. For example A isn't an escape sequence:
$ python3.6 -Wd -c '"A"'
<string>:1: DeprecationWarning: invalid escape sequence A
If your backslash sequence does accidentally match one of Python's escape sequences, but you didn't mean it to, that's even worse.
So you should always use raw strings or \.
It's important to remember that a string literal is still a string literal even if that string is intended to be used as a regular expression. Python's regular expression syntax supports lots of special sequences that begin with . For example A matches the start of a string. But A is not valid in a Python string literal! This is invalid:
my_regex = "Afoo"
Instead you should do this:
my_regex = r"Afoo"
Docstrings are another one to remember: docstrings are string literals too, and invalid sequences are invalid in docstrings too! Use raw strings (r"""...""") for docstrings if they contain 's.
answered Sep 14 at 16:30
Sean Hammond
2,5711025
answered Sep 14 at 16:30
Sean Hammond
2,5711025
answered Sep 14 at 16:30
Sean Hammond
2,5711025
answered Sep 14 at 16:30
Sean Hammond
2,5711025
2,5711025
add a comment |
add a comment |
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