regex – w3toppers.com

Regex for youtube URL

Here’s a regex I use to match and capture the important bits of YouTube URLs with video codes: ^((?:https?:)?\/\/)?((?:www|m)\.)?((?:youtube(-nocookie)?\.com|youtu.be))(\/(?:[\w\-]+\?v=|embed\/|v\/)?)([\w\-]+)(\S+)?$ Works with the following URLs: https://www.youtube.com/watch?v=DFYRQ_zQ-gk&feature=featured //www.youtube.com/watch?v=DFYRQ_zQ-gk www.youtube.com/watch?v=DFYRQ_zQ-gk //youtube.com/watch?v=DFYRQ_zQ-gk youtube.com/watch?v=DFYRQ_zQ-gk //m.youtube.com/watch?v=DFYRQ_zQ-gk m.youtube.com/watch?v=DFYRQ_zQ-gk https://youtube.com/watch?v=DFYRQ_zQ-gk%3Ffs%3D1%26hl%3Den_US https://youtube.com/watch?v=DFYRQ_zQ-gk%3Ffs%3D1%26hl%3Den_US //www.youtube.com/v/DFYRQ_zQ-gk?fs=1&hl=en_US www.youtube.com/v/DFYRQ_zQ-gk?fs=1&hl=en_US youtube.com/v/DFYRQ_zQ-gk?fs=1&hl=en_US https://youtube.com/watch?v=DFYRQ_zQ-gk%3Fautoplay%3D1 //www.youtube.com/embed/DFYRQ_zQ-gk www.youtube.com/embed/DFYRQ_zQ-gk //youtube.com/embed/DFYRQ_zQ-gk youtube.com/embed/DFYRQ_zQ-gk https://www.youtube-nocookie.com/embed/DFYRQ_zQ-gk?autoplay=1 https://www.youtube-nocookie.com/embed/DFYRQ_zQ-gk http://www.youtube-nocookie.com/embed/DFYRQ_zQ-gk //www.youtube-nocookie.com/embed/DFYRQ_zQ-gk www.youtube-nocookie.com/embed/DFYRQ_zQ-gk https://youtube-nocookie.com/embed/DFYRQ_zQ-gk http://youtube-nocookie.com/embed/DFYRQ_zQ-gk //youtube-nocookie.com/embed/DFYRQ_zQ-gk youtube-nocookie.com/embed/DFYRQ_zQ-gk //youtu.be/DFYRQ_zQ-gk youtu.be/DFYRQ_zQ-gk https://www.youtube.com/HamdiKickProduction?v=DFYRQ_zQ-gk The captured … Read more

“Unknown escape sequence” error in Go

The \ backslash isn’t being interpreted by the regex parser, it’s being interpreted in the string literal. You should escape the backslash again: regexp.Compile(“[0-9]+\\.[0-9]+\\.[0-9]+\\.[0-9]+”) A string quoted with ” double-quote characters is known as an “interpreted string literal” in Go. Interpreted string literals are like string literals in most languages: \ backslash characters aren’t included … Read more

Sed to extract text between two strings

sed -n ‘/^START=A$/,/^END$/p’ data The -n option means don’t print by default; then the script says ‘do print between the line containing START=A and the next END. You can also do it with awk: A pattern may consist of two patterns separated by a comma; in this case, the action is performed for all lines … Read more

Is there an R function to escape a string for regex characters

I’ve written an R version of Perl’s quotemeta function: library(stringr) quotemeta <- function(string) { str_replace_all(string, “(\\W)”, “\\\\\\1″) } I always use the perl flavor of regexps, so this works for me. I don’t know whether it works for the “normal” regexps in R. Edit: I found the source explaining why this works. It’s in the … Read more

How to use RegEx in Dart?

This is a more general answer for future viewers. Regex in Dart works much like other languages. You use the RegExp class to define a matching pattern. Then use hasMatch() to test the pattern on a string. Examples Alphanumeric final alphanumeric = RegExp(r’^[a-zA-Z0-9]+$’); alphanumeric.hasMatch(‘abc123’); // true alphanumeric.hasMatch(‘abc123%’); // false Hex colors RegExp hexColor = RegExp(r’^#?([0-9a-fA-F]{3}|[0-9a-fA-F]{6})$’); … Read more

replace a unknown string between two known strings with sed

sed -i ‘s/WORD1.*WORD3/WORD1 foo WORD3/g’ file.txt or sed -i ‘s/(WORD1).*(WORD3)/\1 foo \2/g’ file.txt You might need to escape round brackets, depends on your sed variant.

Replace a word with multiple lines using sed?

You can do this with AWK using variable substitution. We can set a variable in AWK using -v, and then use AWK’s gsub function to substitute all occurrences of a regular expression with that variable. For example, if the file test has the following contents … foo bar blah _data_and_data_ foo _data_ foobar _data_ again … Read more

How to match a pattern given in a variable in awk?

If you want to provide the pattern through a variable, you need to use ~ to match against it: awk -v pat=”$pattern” ‘$0 ~ pat’ In your case, the problem does not have to do with -F. The problem is the usage of /pat/ when you want pat to be a variable. If you say … Read more

How do I remove all non-ASCII characters with regex and Notepad++?

This expression will search for non-ASCII values: [^\x00-\x7F]+ Tick off ‘Search Mode = Regular expression’, and click Find Next. Source: Regex any ASCII character

How do I perform a Perl substitution on a string while keeping the original?

This is the idiom I’ve always used to get a modified copy of a string without changing the original: (my $newstring = $oldstring) =~ s/foo/bar/g; In perl 5.14.0 or later, you can use the new /r non-destructive substitution modifier: my $newstring = $oldstring =~ s/foo/bar/gr; NOTE: The above solutions work without g too. They also … Read more