php preg_match：仅数字字母和逗号
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preg_match: number-alphabets and commas only
提问by laukok
How do I write a regular expression which matches number-alphabets and commas only?
如何编写仅匹配数字字母和逗号的正则表达式？
I came out with this one below but it doesnt work - it accepts other punctuation marks as well!
我在下面提出了这个，但它不起作用 - 它也接受其他标点符号！
# check for matches number-alphabets and commas only
if(!preg_match('/([a-zA-Z0-9]|[a-zA-Z0-9\,])/', $cst_value))
{
$error = true;
echo '<error elementid="usr_username" message="'.$cst_name.' - please use number-alphabets and commas only."/>';
}
Many thanks, Lau
非常感谢，刘
回答by NullUserException
You want:
你要：
/^[a-zA-Z0-9,]+$/
You need the start ^and end $of string anchors. Without them the regex engine will look for any of those characters in the string and if it finds one, it will call it a day and say there's a match. With the anchors, it forces the engine to look at the whole string. Basically:
您需要字符串锚点的开头^和结尾$。如果没有它们，正则表达式引擎将在字符串中查找这些字符中的任何一个，如果找到一个，它将称它为一天并说有一个匹配项。使用锚点，它会强制引擎查看整个字符串。基本上：
/[a-zA-Z0-9,]+/matches if anyof the characters are alphanumeric + comma./^[a-zA-Z0-9,]+$/matches if allof the characters are alphanumeric + comma.
/[a-zA-Z0-9,]+/如果任何字符是字母数字 + 逗号，则匹配。/^[a-zA-Z0-9,]+$/如果所有字符都是字母数字 + 逗号，则匹配。
回答by codaddict
if(preg_match('/^[0-9a-z,]+$/i', $cst_value)) {
// valid input..contains only alphabet,number and comma.
}else{
// invalid
}
We pass the following to preg_match : /^[0-9a-z,]+$/i
我们将以下内容传递给 preg_match ： /^[0-9a-z,]+$/i
Explanation:
解释：
/: regex delimiters.^: start anchor[..]: Char class0-9: any digita-z: any alphabet,: a comma. comma is not a regex metachar, so you need not escape it+: quantifier for one or more. If an empty input is considered valid, change+to*$: end anchori: to make the matching case insensitive.
/: 正则表达式分隔符。^: 开始锚[..]: 字符类0-9: 任何数字a-z: 任何字母,: 逗号。逗号不是正则表达式元字符，因此您无需对其进行转义+: 一个或多个的量词。如果认为空输入有效，则更+改为*$: 结束锚i: 使匹配不区分大小写。
回答by Phill Pafford
Well this adds a couple more characters like underscore
嗯，这增加了几个字符，比如下划线
/^[\w,]*$/
/^[\w,]*$/
But this should work
但这应该有效
/^[a-zA-Z0-9,]*$/
