I'm having trouble figuring out what exactly this regex pattern is searching for mostly due to the number at the end. From what I can tell, it is saying search for any character that is not a-z and repeat it for the whole string. What does the 3 do?
[^a-z.+3]
Thanks!
In a character class all characters loose their special meaning (if any), only the first ^ is used to negate the class, - is used to define a range (except at the first and last position), an eventual backslash may start an escape sequence and ] closes the class.
3 is the literal character 3, + is the literal character +, . is a literal ., nothing more.
[^a-z.+3] matches one character that isn't in this list and is the same as [^.a-z3+] or [^+.a-z3]
[^a-z.+3] match characters other than a-z . + and 3
lets take an example,
x = 'stack overflow... 363 is amazing++useful'
lets take each element in regex one by one.
[^a-z] matches characters other than a-z
In [19]: re.findall(r'[^a-z]', x)
Out[19]: [' ', '.', '.', '.', ' ', '3', '6', '3', ' ', ' ', '+', '+']
[^a-z.] matches characters other than a-z and .
In [20]: re.findall(r'[^a-z.]', x)
Out[20]: [' ', ' ', '3', '6', '3', ' ', ' ', '+', '+']
[^a-z.+] matches characters other than a-z . +
In [21]: re.findall(r'[^a-z.+]', x)
Out[21]: [' ', ' ', '3', '6', '3', ' ', ' ']
[^a-z.+3] matches characters other than a-z . + 3
In [22]: re.findall(r'[^a-z.+3]', x)
Out[22]: [' ', ' ', '6', ' ', ' ']
[^a-z.+3]
[^a-z.+3] match a single character not present in the list below
a-z a single character in the range between a and z (case sensitive)
.+3 a single character in the list .+3 literally
from : https://regex101.com/r/wI5hG2/1
So in one line this match a caracter different of a to z and . and + and 3
