I have a fairly terrible memory but I’ve found writing and referring back to cheatsheets to be a pretty effective way to memorize things.
I ended up referring back to my previous
cheatsheet on git reset
quite a few times soon after I wrote it, so when I came across
this great post on regex features in ruby
I thought I’d share the lookarounds section because I always forget those too!
| Syntax | Description | Example | Result |
|---|---|---|---|
(?=X) |
Positive lookahead | "Ruby"[/.(?=b)/] |
"u" |
(?!X) |
Negative lookahead | "Ruby"[/.(?!u)/] |
"u" |
(?<=X) |
Positive lookbehind | "Ruby"[/(?<=u)./] |
"b" |
(?<!X) |
Negative lookbehind | "Ruby"[/(?<!R|^)./] |
"b" |
Checkout the original blog post for the rest of the regex tips or the Idiosyncratic Ruby site for more ruby tips!