Does forward slash need to be escaped python?
Let me preface this by saying I'm not exactly sure what is happening with my code; I'm fairly new to programming. Show
I've been working on creating an individual final project for my python CS class that checks my teacher's website on a daily basis and determines if he's changed any of the web pages on his website since the last time the program ran or not. The step I'm working on right now is as follows:
The links look similar to this:
And the error I get is as follows:
How can I write the site pages with these types of names (/site/sitename/nameofpage.txt)? Escape CharactersTo insert characters that are illegal in a string, use an escape character. An escape character is a backslash An example of an illegal character is a double quote inside a string that is surrounded by double quotes: ExampleYou will get an error if you use double quotes inside a string that is surrounded by double quotes: txt = "We are the so-called "Vikings" from the north." Try it Yourself » To fix this problem, use the escape character ExampleThe escape character allows you to use double quotes when you normally would not be allowed: txt = "We are the so-called \"Vikings\" from the north." Try it Yourself » Other escape characters used in Python:
If you’re like me, you’ll regularly sit in front of your code and wonder: how to escape a given character? Challenge: Some characters have a special meaning in Python strings and regular expressions. Say you want to to search for string Question: How to escape all special regex symbols automatically? Python Regex - How to Escape Special Characters? If you have this problem too, you’re in luck. This article is the ultimate guide to escape special characters in Python. Just click on the topic that interests you and learn how to escape the special character you’re currently struggling with! If you’re the impatient guy, you’re in luck too. Just try to add the backslash to your special character you want to escape: Here are a few examples: >>> import re >>> re.findall('\( \{ \" \. \* \+', r'( { " . * +') ['( { " . * +'] However, you may not want to escape all of those manually. That’s why the re.escape method exists!
Python re.escape MethodIf you know that your string has a lot of special characters, you can also use the convenience method Specification: Definition: escapes all special regex meta
characters in the given Example: you can escape all special symbols in one go: >>> re.escape('https://www.finxter.com/') 'https://www\\.finxter\\.com/' The dot symbol has a special meaning in the string Note that “only characters that can have special meaning in a regular expression are escaped. As a result, Related article: Python Regex Superpower – The Ultimate Guide Do you want to master the regex superpower? Check out my new book The Smartest Way to Learn Regular Expressions in Python with the innovative 3-step approach for active learning: (1) study a book chapter, (2) solve a code puzzle, and (3) watch an educational chapter video. Python Regex Escape CharactersIf you use special characters in strings, they carry a special meaning. Sometimes you don’t need that. The general idea is to escape the special character In the following, I show how to escape all possible special characters for Python strings and regular expressions: Python Regex Escape Parentheses ()How to escape the parentheses Parentheses have a special meaning in Python regular expressions: they open and close matching groups. You can get rid of the special meaning of parentheses by using the backslash prefix: >>> import re >>> re.findall(r'\(.*\)', 'Python is (really) great') ['(really)'] The result shows a string that contains the “special” characters Python Regex Escape Square Brackets []How to escape the square brackets Square brackets have a special meaning in Python regular expressions: they open and close character sets. You can get rid of the special meaning of brackets by using the backslash prefix: >>> import re >>> re.findall(r'\[.*\]', 'Is Python [really] easy?') ['[really]'] The result shows a string that contains the “special” characters Python Regex Escape Curly Brace (Brackets)How to escape the curly braces The curly braces don’t have any special meaning in Python strings or regular expressions. Therefore, you don’t need to escape them with a leading backslash character >>> import re >>> re.findall(r'\{.*\}', 'if (2==2) { y = 3; }') ['{ y = 3; }'] >>> re.findall(r'{.*}', 'if (2==2) { y = 3; }') ['{ y = 3; }'] >>> re.findall('{.*}', 'if (2==2) { y = 3; }') ['{ y = 3; }'] All three cases match the same
string enclosed in curly braces—even though we did not escape them and didn’t use the raw string Python Regex Escape Slash (Backslash and Forward-Slash)How to escape the slash characters—backslash The backslash has a special meaning in Python regular expressions: it escapes special characters and, thus, removes the special meaning. (How meta.) >>> import re >>> re.findall(r'\\...', r'C:\home\usr\dir\hello\world') ['\\hom', '\\usr', '\\dir', '\\hel', '\\wor'] You can see that the resulting matches have escaped backslashes themselves. This is because the backslash character has a special meaning in normal strings. Thus, the Python interpreter escapes it automatically by itself when printing it on the shell. Note that you didn’t need to escape the backslash characters when writing the raw string >>> re.findall(r'\\...', 'C:\\home\\usr\\dir\\hello\\world') ['\\hom', '\\usr', '\\dir', '\\hel', '\\wor'] In contrast to the backslash, the forward-slash doesn’t need to be escaped. Why? Because it doesn’t have a special meaning in Python strings and regular expressions. You can see this in the following example: >>> import re >>> re.findall('/...', '/home/usr/dir/hello/world') ['/hom', '/usr', '/dir', '/hel', '/wor'] The result shows that even in a non-raw string, you can use the forward-slash without leading escape character. Python Regex Escape String Single QuotesHow to escape the single quotes Single quotes have a special meaning in Python regular expressions: they open and close strings. You can get rid of the special meaning of single quotes by
using the backslash prefix: >>> import re >>> re.findall('\'.*\'', "hello 'world'") ["'world'"] The result shows a string that contains the “special” single quote characters. The result also shows an alternative that removes the special meaning of the single quotes: enclose them in double quotes: Python Regex Escape String Double QuotesHow to escape the
double quotes Double quotes have a special meaning in Python regular expressions: they open and close strings. You can get rid of the special meaning of single quotes by using the backslash prefix: >>> import re >>> re.findall('\".*\"', 'hello "world"') ['"world"'] The result shows a string that contains the “special” single quote characters. The result also shows an alternative that removes the special meaning of the single quotes: enclose them in double quotes: Python Regex Escape Dot (Period)How to escape the regex dot (or period) meta character The dot character has a special meaning in Python regular expressions: it matches an arbitrary character (except newline). You can get rid of the special meaning of the dot character by using the backslash prefix: >>> import re >>> re.findall('..\.', 'my. name. is. python.') ['my.', 'me.', 'is.', 'on.'] The result shows four strings that
contain the “special” characters Python Regex Escape PlusHow to escape the plus symbol The plus symbol has a special meaning in Python regular expressions: it’s the one-or-more quantifier of the preceding regex. You can
get rid of the special meaning of the regex plus symbol by using the backslash prefix: >>> import re >>> re.findall('\++', '+++python+++rocks') ['+++', '+++'] The result shows both usages: the plus symbol with and without leading escape character. If it is escaped Python Regex Escape AsteriskHow to escape the asterisk symbol The asterisk symbol has a special meaning in Python regular expressions: it’s the zero-or-more quantifier of the preceding regex. You can get rid of the special meaning of the regex
asterisk symbol by using the backslash prefix: >>> import re >>> re.findall('\**', '***python***rocks') ['***', '***'] The result shows both usages: the asterisk symbol with and without leading escape character. If it is escaped Python Regex Escape Question MarkHow to escape the question mark symbol The question mark symbol has a special meaning in Python regular expressions: it’s the zero-or-one quantifier of the preceding regex. You can get rid of the special
meaning of the question mark symbol by using the backslash prefix: >>> import re >>> re.findall('...\?', 'how are you?') ['you?'] The result shows that the question mark symbol was matched in the given string. Python Regex Escape UnderscoreHow to escape the underscore character The underscore doesn’t have a special meaning in Python regular expressions or Python strings. Therefore, you don’t need to escape the underscore character—just use it in your regular expression unescaped. >>> import re >>> re.findall('..._', 'i_use_underscore_not_whitespace') ['use_', 'ore_', 'not_'] However, it doesn’t harm to escape it either: >>> re.findall('...\_', 'i_use_underscore_not_whitespace') ['use_', 'ore_', 'not_'] In both cases, Python finds the underscore characters in the string and matches them in the result. Python Regex Escape PipeHow to escape the pipe symbol The pipe symbol has a special meaning in Python regular expressions: the regex OR operator. You can get rid of the special
meaning of the pipe symbol by using the backslash prefix: >>> import re >>> re.findall('.\|.', 'a|b|c|d|e') ['a|b', 'c|d'] By escaping the pipe symbol, you get rid of the special meaning. The result is just the matched pipe symbol with leading and trailing arbitrary character. If you don’t escape the pipe symbol, the result will be quite different: >>> re.findall('.|.', 'a|b|c|d|e') ['a', '|', 'b', '|', 'c', '|', 'd', '|', 'e'] In this case, the regex Python Regex Escape DollarHow to escape the dollar symbol The dollar symbol has a special meaning in Python regular expressions: it matches at the end of the string. You can get rid of the special meaning by using the backslash prefix: >>> import re >>> re.findall('\$\d+', 'Your house is worth $1000000') ['$1000000'] Note that the Python Regex Escape Greater Than and Smaller ThanHow to escape the greater than Greater and smaller than symbols don’t have a special meaning in Python regular expressions. Therefore, you don’t need to escape them. Here’s an example: >>> import re >>> re.findall('<.*>.*<.*>', ' The result shows a string that even without escaping the HTML tag symbols, the regex matches the whole string. Python Regex Escape HyphenHow to escape the hyphen Outside a character set, the hyphen doesn’t have a special meaning and you don’t need to escape it. Here’s an example: >>> import re >>> re.findall('..-', 'this is-me') ['is-'] The unescaped hyphen character in the regex matches the hyphen in the string. However, inside a character set, the hyphen stands for the range symbol (e.g. >>> re.findall('[a-z\-]+', 'hello-world is one word') ['hello-world', 'is', 'one', 'word'] Note that, in this case, if you don’t escape the hyphen in the character set, you get the same result: >>> re.findall('[a-z-]+', 'hello-world is one word') ['hello-world', 'is', 'one', 'word'] The reason is that the hyphen appears at the end of the character set where it can have only one meaning: the hyphen symbol itself. However, in all other cases, the hyphen would be assumed to mean the range character which will result in strange behavior. A good practice is, thus, to escape the hyphen in the character class per default. Python Regex Escape NewlineIn a recent StackOverflow article, I read the following question: I got a little confused about Python raw string. I know that if we use raw string, then it will treat The coder asking the question has understood that the Python interpreter doesn’t assume that the two characters However, those two symbols have a special meaning for the regex engine! So if you use them as a regular expression pattern, they will indeed match the newline character: >>> import re >>> text = '''This is a multiline string''' >>> re.findall(r'[a-z]+\n', text) ['his\n', 'is\n', 'a\n', 'multiline\n'] Therefore, you don’t need to escape the newline character again to match it in a given string. Python Regex Bad EscapeThere are some common errors in relation to escaping in Python regular expressions. If you try to escape a normal character that has not a special meaning, Python will throw a “bad escape error”: >>> re.findall('\m', 'hello {world}') Traceback (most recent call last): File " As the error message
suggests, there’s no escape sequence Where to Go From HereWow, you either have read about a lot of escaped character sequences or you did a lot of scrolling to reach this point. In both cases, you have a great advantage over other coders: you’re a persistent guy or gal! Do you want to increase your advantage over your peers? Then join my Python email academy! I’ll teach you the ins and outs of Python coding—all free! Join Finxter Email Academy, become a better coder, and download your free Python cheat sheets! While working as a researcher in distributed systems, Dr. Christian Mayer found his love for teaching computer science students. To help students reach higher levels of Python success, he founded the programming education website Finxter.com. He’s author of the popular programming book Python One-Liners (NoStarch 2020), coauthor of the Coffee Break Python series of self-published books, computer science enthusiast, freelancer, and owner of one of the top 10 largest Python blogs worldwide. His passions are writing, reading, and coding. But his greatest passion is to serve aspiring coders through Finxter and help them to boost their skills. You can join his free email academy here. Do I need to escape a forward slash in Python?Programming languages, such as Python, treat a backslash (\) as an escape character. For instance, \n represents a line feed, and \t represents a tab. When specifying a path, a forward slash (/) can be used in place of a backslash. Two backslashes can be used instead of one to avoid a syntax error.
Do we need to escape forward slash?What context/language? Some languages use / as the pattern delimiter, so yes, you need to escape it, depending on which language/context. You escape it by putting a backward slash in front of it: \/ For some languages (like PHP) you can use other characters as the delimiter and therefore you don't need to escape it.
Do you need to escape forward slash in JSON?JSON doesn't require you to do that, it allows you to do that. It also allows you to use "\u0061" for "A", but it's not required, like Harold L points out: The JSON spec says you CAN escape forward slash, but you don't have to.
How do you use a forward slash in a string in Python?Use the str. split() method to split a string on the forward slashes, e.g. my_list = my_str. split('/') .
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