Lessons · Regex · any one character
Any one character
The dot matches exactly one character of any kind, except a newline.
Hone is a place to practise programming. This is one of its lessons, written out in full and free to read without an account.
What it is for
Wildcards in names and codes, 'a then something then b', skipping a character you do not care about.
How to think about it
Is exactly one unknown character allowed here? Use a dot for that spot. For 'anything of any length' it is .* and for 'anything but X' a negated class is safer than a dot.
Worked example
pattern: ^h.t$h, any one character, t.
text: hatMatch. hot and hit too.
text: heatNo match: two characters in the middle.
Your turn
Match 'c', any character, 'p' as a whole string.
^cp$
Test a pattern against real text
The trap
A dot where you meant a literal full stop. 1.5 as a pattern matches 125. Escape it: 1\.5.
Practise any one character on HoneA question on it now, a coding challenge where there is one, and it is remembered for review. Free, no email needed.