这个正则表达式(Php)是什么意思？

Question

$str = "Instant Oats Drink - Chocolate Flavour 165g (33g x 5)";

preg_match('/(?P<title>.*) (?P<grammars>\d+g) \((?P<portion>\d+g) x (?P<times>\d+)\)/', $str, $m);

echo "Title : " . $m['title'] . '<br />';
echo "Grammars : " . $m['grammars'] . '<br />';
echo "Portion : " . $m['portion'] . '<br />';
echo "Times : " . $m['times'] . '<br />';

我真的不知道preg_match是什么意思。例如"?P<title>"、"\d+g"

Answer 1

$str =“速溶燕麦饮料-巧克力口味165g (33gx5)”；

/(?P<title>.*) (?P<grammars>\d+g) \((?P<portion>\d+g) x (?P<times>\d+)\)/

在英语中应该是这样的：

查找一个或多个字符--将其称为“标题”(速溶燕麦饮料-巧克力口味)

--然后是--

一个空格

--然后是--

一个或多个以“g”结尾的数字--称之为“语法”(165g)

--然后是--

一个空格

--然后是--

括号'(‘

--然后是--

以g结尾的一个或多个数字(\d+) --调用\d+g‘\d+’(33g)

--然后是--

后跟x和空格的空格。(X)

--然后是--

一个或多个数字--称之为“时间”( 5)

Answer 2

出自preg_match()手册

命名子模式现在接受语法(?)和(?'name')以及(?P)。以前的版本仅接受(?P)。

所以，(?P<grammars>.*)会让你在$m['grammars']中有一个值

\d+匹配1个或多个数字，g匹配字母g

匹配任何字符的贪婪匹配，0次或更多次-在您的示例中，此匹配将放入title或grammars .*变量中。

我建议您阅读一些基本的正则表达式教程-- .*构造是非常基础的

Answer 3

意思是这样的：

# (?P<title>.*) (?P<grammars>\d+g) \((?P<portion>\d+g) x (?P<times>\d+)\)

# 
# Match the regular expression below and capture its match into
#  backreference with name “title” «(?P<title>.*)»

#    Match any single character that is not a line break character «.*»
#       Between zero and unlimited times, as many times as possible, giving back as needed (greedy) «*»
# Match the character “ ” literally « »
# Match the regular expression below and capture its match into backreference with name “grammars” «(?P<grammars>\d+g)»
#    Match a single digit 0..9 «\d+»
#       Between one and unlimited times, as many times as possible, giving back as needed (greedy) «+»
#    Match the character “g” literally «g»
# Match the character “ ” literally « »
# Match the character “(” literally «\(»
# Match the regular expression below and capture its match into backreference with name “portion” «(?P<portion>\d+g)»
#    Match a single digit 0..9 «\d+»
#       Between one and unlimited times, as many times as possible, giving back as needed (greedy) «+»

#    Match the character “g” literally «g»
# Match the characters “ x ” literally « x »
# Match the regular expression below and capture its match into backreference with name “times” «(?P<times>\d+)»
#    Match a single digit 0..9 «\d+»
#       Between one and unlimited times, as many times as possible, giving back as needed (greedy) «+»
# Match the character “)” literally «\)»

这就是regexbuddy的输出。应该使用正则表达式帮助器。帮助很大:)