替换所有其他角色

Question

how could i skip or replace every other character (could be anything) with regex?

"abc123.-def45".gsub(/.(.)?/, '@')

to get

"a@c@2@.@d@f@5"

Answer 1

Capture the first character instead, and write it back:

"abc123.-def45".gsub(/(.)./, '\1@')

It's important that you don't make the second character optional. Otherwise, in an odd-length string, the last character would lead to a match, and a @ would be appended. Without the ? , the last character will simply fail and remain untouched.

Working demo.

Answer 2

您也可以这样做以避免在序列中替换@

"abc123.-def45".gsub(/([^@])[^@]/, '\1@')

Answer 3

The below code will also work:

irb(main):005:0> "abc123.-def45".chars.each_with_index.map {|e,i| !i.even? ? e = "@" : e}.join
=> "a@c@2@.@d@f@5"