急问如何利用perl统计一行字符串里的指定字符的个数

Question

用的是perl，想用正则表达式写。譬如给的字符串是abcsfsaf#sdagasdga#sdgaghoiiopjh#dsfjkopa hkl;fjh#dsjfklpafj
我希望的结果是统计出#号有4个。求高手帮忙

Answer 1

三个方法如下：
#!/bin/perl -w
use strict;

my $str = "abcsfsaf#sdagasdga#sdgaghoiiopjh#dsfjkopa hkl;fjh#dsjfklpafj";

########### 方法一
my $pos = -1;
my $num = 0;
while (($pos = index($str, "#", $pos)) > -1) {
print "Found at $pos\n";
$pos++;
$num ++;
}
print "找到$num个!\n";

###############################################################
# 方法二

my $count = 0;
while( $str =~ /#/g )
{
$count ++;
}
print $count,"\n";

##########################################
# 方法3
my $cc = 0;
my $tmp = 0;
if( $tmp = () = ($str =~ /#/g ) )
{
$cc += $tmp;
}
print "$cc\n";