Character classes for filtering text with grep (Episode #11) 

One Minute One-liners for the curious: https://www.youtube.com/@1minute1liners

In this YouTube short from One Minute One-liners for the curious(@1minute1liner), I explain how to use character classes as an easy way to filter text using GREP. We built a PARI function that extracts characters in a string by character class: extract(str,class,{not=0}). We also built an Octave function as well.

You can test with the following two line examples.

GP/PARI:
strout=strchr(Vecsmall([1..127]));
a=extract(strout,"alnum"); #a

Octave:
strout=char([1:127]);
a=extract(strout,"alnum");length(a)

You can write out a file containing all 128 7 bit ascii characters in a chars file for testing.  Here is jab.txt as well.