可选的空白正则表达式 [英] Optional Whitespace Regex

问题描述

我在尝试忽略某些字符之间的空格时遇到问题.我已经搜寻了几天，似乎找不到正确的解决方案.

I'm having a problem trying to ignore whitespace in-between certain characters. I've been Googling around for a few days and can't seem to find the right solution.

这是我的代码:

// Get Image data
preg_match('#<a href="(.*?)" title="(.*?)"><img alt="(.*?)" src="(.*?)"[\s*]width="150"[\s*]height="(.*?)"></a>#', $data, $imagematch);
$image = $imagematch[4];

基本上，这是我遇到的一些情况:

Basically these are some of the scenarios I have:

 <a href="/wiki/File:Sky1.png" title="File:Sky1.png"><img alt="Sky1.png" src="http://media-mcw.cursecdn.com/thumb/5/56/Sky1.png/150px-Sky1.png"width="150" height="84"></a>

(请注意，width ="和src ="之间没有空格)

(Notice the lack of a space between width="" and src="")

还有

<a href="/wiki/File:TallGrass.gif" title="File:TallGrass.gif"><img alt="TallGrass.gif" src="http://media-mcw.cursecdn.com/3/34/TallGrass.gif" width="150"height="150"></a>

(请注意，在width ="和height ="之间没有空格.)

(Notice the lack of a space in between width="" and height="".)

是否有任何地方可以忽略这些字符之间的空格?因为我不是Regex专家.

Is there anyway to ignore the whitespace in between those characters? As I am not a Regex expert.

推荐答案

如果可以允许空格，请添加\s?.

Add a \s? if a space can be allowed.

\ s 代表空白

?说前面的字符可能出现一次或不发生.

? says the preceding character may occur once or not occur.

如果允许多个空格并且是可选空格，请使用\s*.

If more than one spaces are allowed and is optional, use \s*.

* 说前面的字符可以出现零次或多次.

* says preceding character can occur zero or more times.

'#<a href\s?="(.*?)" title\s?="(.*?)"><img alt\s?="(.*?)" src\s?="(.*?)"[\s*]width\s?="150"[\s*]height\s?="(.*?)"></a>#'

在属性名称和=之间留有一个可选空格.

allows an optional space between attribute name and =.

如果您还希望在=后面添加一个可选空格，请在其后也添加一个\s?.

If you want an optional space after the = also, add a \s? after it also.

同样，无论您在何处有可选字符，如果最大出现次数是 1 ，则可以使用?；如果最大出现次数是无限的，则可以使用*(在可选字符之后).

Likewise, wherever you have optional characters, you can use ? if the maximum occurrence is 1 or * if the maximum occurrence is unlimited, following the optional character.

您的实际问题是[\s*]，由于[和]中包含的字符是字符类，导致出现空白或 a * .字符类允许一次其任何成员出现(因此从中删除*)，并且如果在]任何字符之后附加了量词(?，+，*等)字符类中的字符可以根据量词出现.

And your actual problem was [\s*] which causes occurrence of a whitespace or a * as characters enclosed in [ and ] is a character class. A character class allows occurrence of any of its members once (so remove * from it) and if you append a quantifier (?, +, * etc) after the ] any character(s) in the character class can occur according to the quantifier.

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