Question

我正在尝试使用正则表达式来检查php脚本中电子邮件地址的有效性。我使用以下字符串作为我的正则表达式

$reg = "\/^([A-Za-z0-9_\-\.])+\@([A-Za-z0-9_\-\.])+\.([A-Za-z]{2,4})\$\/";

我一直收到错误：

 Warning: preg_match(): Delimiter must not be alphanumeric or backslash

我尽力逃脱所有特殊角色。有什么我想念的吗？

Answer 1

你逃脱了分界符，f.e：

$sCorrect = "/[a-z]/";
$sFalse = "\/[a-z]\/";

更好的是，使用：

filter_var($sVariable, FILTER_VALIDATE_EMAIL);

Answer 2

你逃脱了太多字符：

$reg = "/^([A-Za-z0-9_\-.])+@([A-Za-z0-9_\-.])+\.([A-Za-z]{2,4})$/";

/正则表达式分隔符（在你的正则表达式的开头和结尾）不应该被转义
不应转义元字符^和$。
当点在字符类
@不需要转义（但可以）

无论如何，创建自己的正则表达式以验证电子邮件地址可能会非常棘手。很可能您不允许有效的电子邮件（例如：+是您不允许的有效字符）和/或允许无效的电子邮件。我相信这个标准是由RFC 822设定的 - 而且它们是loooooooong。

按照Wesley的建议使用filter_var()。或者更好的是，发送电子邮件到提供的地址。这是确定地址是否

的最佳和最可靠的方法

a）有效
b）属于用户

有趣的读物：I Knew How To Validate An Email Address Until I Read The RFC

Answer 3

$reg = "/\b[A-Z0-9._%+-]+@[A-Z0-9.-]+\.[A-Z]{2,6}\b/i"

使用new Gtld's

说明：

# Options: case insensitive
# 
# Assert position at a word boundary «\b»
# Match a single character present in the list below «[A-Z0-9._%+-]+»
#    Between one and unlimited times, as many times as possible, giving back as needed (greedy) «+»
#    A character in the range between “A” and “Z” «A-Z»
#    A character in the range between “0” and “9” «0-9»
#    One of the characters “._%” «._%»
#    The character “+” «+»
#    The character “-” «-»
# Match the character “@” literally «@»
# Match a single character present in the list below «[A-Z0-9.-]+»
#    Between one and unlimited times, as many times as possible, giving back as needed (greedy) «+»
#    A character in the range between “A” and “Z” «A-Z»
#    A character in the range between “0” and “9” «0-9»
#    The character “.” «.»
#    The character “-” «-»
# Match the character “.” literally «\.»
# Match a single character in the range between “A” and “Z” «[A-Z]{2,6}»
#    Between 2 and 6 times, as many times as possible, giving back as needed (greedy) «{2,6}»
# Assert position at a word boundary «\b»

Php正则表达式字符串需要更多分隔符？

3 个答案: