How to find the 3rd occurrence of a pattern on a line

问题

Today I had to align a table at only the first multiple spaces on a line.

p.e.

<ScrollWheelDown>    move window     three lines     down  
<S-ScrollWheelDown>     move window    one page   down
<ScrollWheelUp>        move window      three lines up
<S-ScrollWheelUp>    move window   one page      up

I use Tabular plugin to align tables but I could not find a way how to find only the first occurrence of multiple spaces and do an align only there.

I don't know it either in VIM: What will be the regex if I only want to find the 3rd occurrence of a pattern on a line? Is the regex the same as using Tabular?

回答1:

The regex would be:

/\(.\{-}\zsPATTERN\)\{3}

So if, for example, you want to change the 3rd 'foo' to 'bar' on the following line:

lorem ifoopsum foo lor foor ipsum foo dolor foo
       ^1      ^2      ^3         ^4        ^5

run:

s/\(.\{-}\zsfoo\)\{3}/bar/

to get:

lorem ifoopsum foo lor barr ipsum foo dolor foo
       ^1      ^2      ^3=bar     ^4        ^5

回答2:

I don't know if it fits your needs, but you can search that way :

Place your cursor at the beginning line
Type 3 / pattern Return

It place the cursor on the 3rd occurrence of the next matching line (highlighting all occurrences)

You can also macro :

qa+3nq

then @a to go to the next line 3rd occurence

回答3:

For Google users (like me) that search just for: "regex nth occurrence". This will return position of last character of third 'foo' (you need to change {3} to your n and foo to your text):

length(regexp_replace('lorem ifoopsum foo lor foor1 ipsum foo dolor foo', '((?:.*?foo){3}).*$', '\1'))

This: (?:.*?foo) searches for anything followed by 'foo', then it is repeated 3 times (?:.*?foo){3}, then string from start to (including) 3rd repetition is captured, then rest of string is matched by .*$, then whole string is replaced by captured thing, and length of it is position of last character of 3rd 'foo'.