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单引号与双引号的区别解决方案

Jun 13, 2016 am 10:14 AM
explode post quot source

单引号与双引号的区别
textarea里有两行数据,name=source
aaaaaaaaaaa
bbbbbbbbbbb

我用explode("\r\n",$_POST['source'])结果有两个元素
用explode('\r\n',$_POST['source'])只有一个元素

------解决方案--------------------
至于你这个地方,可以很负责人的告诉你,是用单引号的。

比如$src = explode( ',', $src );
------解决方案--------------------
$str="hello";
echo '$str'; //解析不了 结果为:$str
echo "$str"; //解析了 结果为 hello

这就是单引号和双引号的区别 
 呵呵 查查资料吧 很久没有与php打交道了
------解决方案--------------------
php如果遇到双引号,会解析双引号里面的变量,如"$i"会被执行,显示i变量的值

但是如果你把'$i'变量放在单引号里,那Php就会直接输出$i也页面上显示,而不会显示变量i的实际值
------解决方案--------------------
双引号会对其中的变量展开,如$varname=hello, "123{$varname}123"最终为"123hello123";双引号会对其中的转义字符进行转义,如"\n\r"就是回车换行。
单引号不对变量展开;不对冒似转义字符进行转义,除了单引号本身,'\n\r'就是这4个字符,没什么其他意思。
------解决方案--------------------

探讨

php如果遇到双引号,会解析双引号里面的变量,如"$i"会被执行,显示i变量的值

但是如果你把'$i'变量放在单引号里,那Php就会直接输出$i也页面上显示,而不会显示变量i的实际值

------解决方案--------------------
探讨
textarea里有两行数据,name=source
aaaaaaaaaaa
bbbbbbbbbbb

我用explode("\r\n",$_POST['source'])结果有两个元素
用explode('\r\n',$_POST['source'])只有一个元素

------解决方案--------------------
在单引号串中甚至反斜杠也失去了他的扩展含义(除了插入反斜杠\\和插入单
引号\')。所以,当你想在字串中进行变量代换和包含\n(换行符)等转义序列时,你应该使用双引
号。
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