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Regex empty string or email
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This regex pattern will match an empty string:
^$
And this will match (crudely) an email or an empty string:
(^$|^.*@.*\..*$)
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Python: List vs Dict for look up table
...f you don't need to associate values, use sets.
Memory
Both dictionaries and sets use hashing and they use much more memory than only for object storage. According to A.M. Kuchling in Beautiful Code, the implementation tries to keep the hash 2/3 full, so you might waste quite some memory.
If you...
How to delete duplicate lines in a file without sorting it in Unix?
...ay then seen[$0] will evaluate to false. The ! is the logical NOT operator and will invert the false to true. Awk will print the lines where the expression evaluates to true. The ++ increments seen so that seen[$0] == 1 after the first time a line is found and then seen[$0] == 2, and so on.
Awk eval...
How to exclude a directory in find . command
I'm trying to run a find command for all JavaScript files, but how do I exclude a specific directory?
38 Answers
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FFmpeg: How to split video efficiently?
...ers that question, so I did as @AlcubierreDrive suggested…
echo "Two commands"
time ffmpeg -v quiet -y -i input.ts -vcodec copy -acodec copy -ss 00:00:00 -t 00:30:00 -sn test1.mkv
time ffmpeg -v quiet -y -i input.ts -vcodec copy -acodec copy -ss 00:30:00 -t 01:00:00 -sn test2.mkv
echo "One comman...
Remove all special characters with RegExp
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The caret (^) character is the negation of the set [...], gi say global and case-insensitive (the latter is a bit redundant but I wanted to mention it) and the safelist in this example is digits, word characters, underscores (\w) and whitespace (\s).
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Listing only directories using ls in Bash?
This command lists directories in the current path: ls -d */
26 Answers
26
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Regular expression for first and last name
For website validation purposes, I need first name and last name validation.
23 Answers
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How to achieve function overloading in C?
... No. printf is not function overloading. it uses vararg !!! And C doesn't support Function Overloading.
– hqt
Jul 29 '12 at 9:49
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Save all files in Visual Studio project as UTF-8
... into a specific character encoding. I got a solution with mixed encodings and I want to make them all the same (UTF-8 with signature).
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