php ereg_replace 到 preg_replace？
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ereg_replace to preg_replace?
提问by sml
How can I convert
我该如何转换
ereg_replace(".*\.(.*)$","\1",$imgfile);
to
到
preg_replace... ?
?
?
I'm having trouble with it?
我有问题吗？
回答by Sumoanand
You should know 4 main things to port ereg patterns to preg:
您应该知道将 ereg 模式移植到 preg 的 4 个主要事项：
Add delimiters(/):
'pattern' => '/pattern/'Escape delimiterif it is a part of the pattern:
'patt/ern' => '/patt\/ern/'
Achieve it programmatically in following way:$ereg_pattern = '<div>.+</div>';$preg_pattern = '/' .addcslashes($ereg_pattern, '/') . '/';eregi(case-insensitive matching):
'pattern' => '/pattern/i'So, if you are using eregi function for case insenstive matching, just add 'i' in the end of new pattern('/pattern/').ASCII values: In ereg, if you use number in the pattern, it is assumed that you are referring to the ASCII of a character. But in preg, number is not treated as ASCII value. So, if your pattern contain ASCII value in the ereg expression(for example: new line, tabs etc) then convert it to hexadecimal and prefix it with \x.
Example: 9(tab) becomes \x9 or alternatively use \t.
添加分隔符(/)：
'pattern' => '/pattern/'如果它是模式的一部分，则转义分隔符：
'patt/ern' => '/patt\/ern/'
通过以下方式以编程方式实现它：$ereg_pattern = '<div>.+</div>';$preg_pattern = '/' .addcslashes($ereg_pattern, '/') . '/';eregi（不区分大小写匹配）：
'pattern' => '/pattern/i'因此，如果您使用 eregi 函数进行不区分大小写匹配，只需在新模式（'/pattern/'）的末尾添加 'i'。ASCII 值：在 ereg 中，如果您在模式中使用数字，则假定您指的是字符的 ASCII。但在 preg 中，数字不被视为 ASCII 值。因此，如果您的模式在 ereg 表达式中包含 ASCII 值（例如：换行、制表符等），则将其转换为十六进制并以 \x 为前缀。
Example: 9(tab) becomes \x9 or alternatively use \t.
Hope this will help.
希望这会有所帮助。
回答by Matthew Flaschen
preg_replace("/.*\.(.*)$/", "\1", "foo.jpg")
I don't know why PHP requires the /delimiters. The only reason Perl, JS, etc. have them is that they allow regex literals, which PHP doesn't.
我不知道为什么 PHP 需要/分隔符。Perl、JS 等拥有它们的唯一原因是它们允许正则表达式文字，而 PHP 则不允许。
回答by Jimmy Ruska
delimiters, add any char to beginning and end of expression, in this case, and by tradition, the '/' character preg_replace('/.*\.(.*)$/',"\\1",$imgfile);The regex isn't very good, better to use strrpos and take substr().
分隔符，在表达式的开头和结尾添加任何字符，在这种情况下，按照传统，'/' 字符preg_replace('/.*\.(.*)$/',"\\1",$imgfile);正则表达式不是很好，最好使用 strrpos 并采用 substr()。
Regex is slow, use this. $extension=substr($imgName,strrpos($imgName,'.'));
正则表达式很慢，使用这个。$extension=substr($imgName,strrpos($imgName,'.'));
