检查“不为空”或空字符串的 PHP 语法是什么？
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What is the PHP syntax to check "is not null" or an empty string?
提问by I wrestled a bear once.
Possible Duplicate:
Check if a variable is empty
可能的重复：
检查变量是否为空
Simple PHP question:
简单的 PHP 问题：
I have this stement:
我有这个词干：
if (isset($_POST["password"]) && ($_POST["password"]=="$password")) {
...//IF PASSWORD IS CORRECT STUFF WILL HAPPEN HERE
}
Somewhere above this statement I use the following line in my JavaScript to set the username as a variable both in my JavaScript and in my PHP:
在此语句上方的某处，我在 JavaScript 中使用以下行将用户名设置为 JavaScript 和 PHP 中的变量：
uservariable = <?php $user = $_POST['user']; print ("\"" . $user . "\"")?>;
What I want to do is add a condition to make sure $user is not null or an empty string (it doesn't have to be any particular value, I just don't want it to be empty. What is the proper way to do this?
我想要做的是添加一个条件以确保 $user 不是 null 或空字符串（它不必是任何特定的值，我只是不希望它为空。正确的方法是什么？做这个？
I know this is a sill question but I have no experience with PHP. Please advise, Thank you!
我知道这是一个sill 问题，但我没有PHP 的经验。请指教，谢谢！
回答by John Green
Null OR an empty string?
Null 或空字符串？
if (!empty($user)) {}
Use empty().
使用空（）。
After realizing that $user ~= $_POST['user'] (thanks matt):
在意识到 $user ~= $_POST['user'] 之后（感谢 matt）：
var uservariable='<?php
echo ((array_key_exists('user',$_POST)) || (!empty($_POST['user']))) ? $_POST['user'] : 'Empty Username Input';
?>';
回答by John Conde
Use empty(). It checks for both empty strings and null.
使用empty(). 它检查空字符串和空字符串。
if (!empty($_POST['user'])) {
// do stuff
}
From the manual:
从手册：
The following things are considered to be empty:
以下内容被认为是空的：
"" (an empty string)
0 (0 as an integer)
0.0 (0 as a float)
"0" (0 as a string)
NULL
FALSE
array() (an empty array)
var $var; (a variable declared, but without a value in a class)
