php 检查变量长度是否等于一个值
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php check if variable length equals a value
提问by mrpatg
Need to check if $messagelength is 7 characters or less, if so, do action A, if not, do action B. Is this correct syntax? I think im doing something wrong?
需要检查$message长度是否为 7 个字符或更少，如果是，则执行操作 A，否则执行操作 B。这是正确的语法吗？我想我做错了什么？
<?php
if (strlen($message) <= 7) {
echo $actiona;
} else {
echo $actionb;
}
?>
回答by Evan Fosmark
It's fine. For example, let's run the following:
没关系。例如，让我们运行以下命令：
<?php
$message = "Hello there!";
if (strlen($message) <= 7){
echo "It is less than or equal to 7 characters.";
}
else
{
echo "It is greater than 7 characters.";
}
?>
It will print: "It is greater than 7 characters."
它将打印：“它大于 7 个字符。”
回答by Randell
You might also want to use the PHP shorthand if/else using the ternary operators (?:).
您可能还想使用 PHP 速记 if/else 使用三元运算符 (?:)。
For example, instead of:
例如，而不是：
<?php
if (strlen($message) <= 7) {
echo $actiona;
} else {
echo $actionb;
}
?>
You can write it as:
你可以把它写成：
<?php echo strlen($message) <= 7 ? $actiona : $actionb; ?>
See How do I use shorthand if / else?for information on the ternary operator.
请参阅如何使用速记 if / else？有关三元运算符的信息。
回答by EvilChookie
What error messages are you receiving?
您收到什么错误消息？
I would check that when you set $messagebefore hand, you haven't misspelt it or used incorrect capitalization (keeping in mind that php is cAsE sensitive).
我会检查当您$message事先设置时，您没有拼错或使用不正确的大写（请记住，php 是 cAsE 敏感的）。
回答by Pascal MARTIN
That's OK.
没关系。
But you should use long php tags (short tags can be disabled ; and quite often are) :
但是您应该使用长 php 标签（可以禁用短标签；而且通常是这样）：
<?php
// ... PHP code
?>
(closing tag being optional, if your file contains only PHP)
（结束标记是可选的，如果您的文件只包含 PHP）
回答by Constantin
i found this ISSET "trick"around www , i don't remember where. try first to run the script like this then uncomment the 2nd line $message=.. to write over another string length..
我在 www 周围发现了这个ISSET“技巧”，我不记得在哪里。首先尝试像这样运行脚本，然后取消注释第二行 $message=.. 以覆盖另一个字符串长度..
<?php
$actiona="ACTIONA";
$actionb="ACTIONB";
$message="1234567";
//$message="12345678";//try to comment /uncomment these
if (!isset($message{7})) {
echo $actiona;
} else {
echo $actionb;
}
?>
AND SURE
当然
<?php
$actiona="ACTIONA";
$actionb="ACTIONB";
$message="1234567";//try to comment /uncomment these
//$message="12345678";
echo !isset($message{7}) ? $actiona : $actionb;
?>
Good luck! We All Love Php !!!!
祝你好运！我们都爱 PHP !!!!
