Php 删除字符串开头和结尾的特定字符
我正在使用PHP,我正在尝试删除字符串末尾和开头的所有下划线字符 下面是字符串:Php 删除字符串开头和结尾的特定字符,php,replace,Php,Replace,我正在使用PHP,我正在尝试删除字符串末尾和开头的所有下划线字符 下面是字符串:\uuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuu 我希望结果是:a_b_c 我已尝试使用此正则表达式,但它不起作用: preg_replace('/[^a-z]+\Z/i', '', '____a_b_c__________'); 为什么不直接使用: 正则表达式用于模式
\uuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuu
我希望结果是:a_b_c
我已尝试使用此正则表达式,但它不起作用:
preg_replace('/[^a-z]+\Z/i', '', '____a_b_c__________');
为什么不直接使用:
正则表达式用于模式匹配\uuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuu
不是一种模式
但如果我要用正则表达式,我会这样做:
$string = preg_replace('/^_+|_+$/', '', $string);
对于正则表达式
^
是一行的开头
\
是下划线,+
是一个或多个下划线
|
是或
\
是下划线,+
是一个或多个下划线
$
是行的结尾
那么我们就用'
替换它,为什么不直接使用:
正则表达式用于模式匹配\uuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuu
不是一种模式
但如果我要用正则表达式,我会这样做:
$string = preg_replace('/^_+|_+$/', '', $string);
对于正则表达式
^
是一行的开头
\
是下划线,+
是一个或多个下划线
|
是或
\
是下划线,+
是一个或多个下划线
$
是行的结尾
然后我们就用'
Ha替换它!我真不敢相信会那么容易。谢谢。对我来说一切都很简单,几乎所有的事情都很简单。这个怎么样:我如何从字符串中删除所有重复和三次重复的下划线。有时甚至可能有5-10个下划线,我只希望它是一个下划线
或'/.+/'
或$string=preg\u replace(['/^.+.+$/','/.{2,}/'],['''.'.'],$string)代码>哈!我真不敢相信会那么容易。谢谢。对我来说一切都很简单,几乎所有的事情都很简单。这个怎么样:我如何从字符串中删除所有重复和三次重复的下划线。有时甚至可能有5-10个下划线,我只希望它是一个下划线
或'/.+/'
或$string=preg\u replace(['/^.+.+$/','/.{2,}/'],['''.'.'],$string)代码>