[^.]+\.(txt|html)
I am learning regex, and am trying to parse this.
[^.] The ^ means "not", and the dot is a wildcard that means any character, so this means find a match with "not any character"? I still don't understand this. Can anyone explain?
The plus is a Kleene Plus which means "1 or more". So now it's "one or more" "not any character".
I get \., it means a period.
(txt|html) means match with a txt file or html file. I think I understand everything after the plus sign. What I don't understand is why it doesn't look something the DOS equivalent where I can just do this: *.txt or *.(txt|html) where * means everything that ends in the file extension .txt or .html?
Is [^.] the equivalent of * in DOS?
The dot (.) has no special meaning when it's inside a character class, and doesn't require to be escaped.
[^.] means "any character that is not a literal . character". [^.]+ matches one or more occurrences of any character that is not a dot.
From regular-expressions.info:
In most regex flavors, the only special characters or meta-characters inside a character class are the closing bracket (
]), the backslash (\), the caret (^), and the hyphen (-). The usual meta-characters are normal characters inside a character class, and do not need to be escaped by a backslash. Your regex will work fine if you escape the regular metacharacters inside a character class, but doing so significantly reduces readability.
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