How to do this job with regular expression

[news.hinet.net]

$a=~/\s{10,}?/

It can find that $a match spaces at least 10 times.

but how to find that if $a have the same word at last 4 times.
like. 666666 222222 11111 aaaaa bbbb

 

[Brian McCauley]

news.hinet.net wrote:

[ Unless you really are the Usenet admin for Hinet you should change
your missleading "From" header ].

$a=~/\s{10,}?/

Note: At the end of a regex {10,}? ("as few as possible but at least 10
times") is the same as simply {10} ("exactly 10 time")

It can find that $a match spaces at least 10 times.

but how to find that if $a have the same word at last 4 times.

By 'word' I shall assume you meant to say 'word character'.

/(\w)\1{9}/

I'm fairly sure this is a FAQ but I don't seem to be able to find it in
the list.

 

[Josef Moellers]

$a=~/\s{10,}?/

It can find that $a match spaces at least 10 times.

but how to find that if $a have the same word at last 4 times.
like. 666666 222222 11111 aaaaa bbbb

You probably mean "letter" rather than "word", as there are no two
identical words in that line.

The keyword you are looking for is "backreference", e.g.
$a =~ /(.)\1\1\1/;
matches 4 identical anythings in $a.
You can put more complex patterns between the parentheses if you desire.