PHP 中的 .= 运算符是什么意思？
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What does the .= operator mean in PHP?
提问by codacopia
I have a variable that is being defined as
我有一个被定义为的变量
$var .= "value";
How does the use of the dot equal function?
dot equal函数的使用方法是什么？
回答by Blender
It's the concatenating assignment operator. It works similarly to:
它是连接赋值运算符。它的工作原理类似于：
$var = $var . "value";
$x .=differs from $x = $x .in that the former is in-place, but the latter re-assigns $x.
$x .=不同之处在于$x = $x .前者是就地的，但后者重新分配了$x。
回答by Prasanth Bendra
This is for concatenation
这是为了串联
$var = "test";
$var .= "value";
echo $var; // this will give you testvalue
回答by AlphaMale
the "." operator is the string concatenation operator. and ".=" will concatenate strings.
" ." 运算符是字符串连接运算符。和 " .=" 将连接字符串。
Example:
例子：
$var = 1;
$var .= 20;
This is same as:
这与：
$var = 1 . 20;
the ".=" operator is a string operator, it first converts the values to strings; and since "." means concatenate / append, the result is the string "120".
" .=" 运算符是一个字符串运算符，它首先将值转换为字符串；由于“ .”表示连接/追加，因此结果是字符串“ 120”。
回答by airider74
In very plain language, what happens is that whatever is stored in each variable is converted to a string and then each string is placed into a final variable that includes each value of each variable put together.
用非常简单的语言来说，发生的事情是将每个变量中存储的任何内容转换为字符串，然后将每个字符串放入最终变量中，该变量包含每个变量的每个值放在一起。
I use this to generate a random variable of alpha numeric and special characters. Example below:
我用它来生成一个由字母数字和特殊字符组成的随机变量。下面的例子：
function generateRandomString($length = 64) {
$characters = '0123456789-!@#$%^*()?:abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ';
$charactersLength = mb_strlen($characters);
$randomString = '';
for ($i = 0; $i < $length; $i++) {
$randomString .= $characters[rand(0, $charactersLength - 1)];
}
return $randomString;
}
then to get the value of $randomString I assign a variable to the function like so
然后为了获得 $randomString 的值，我将一个变量分配给函数，就像这样
$key = generateRandomString();
echo $key;
What this does is pick a random character from any of the characters in the $characters variable. Then .= puts the result of each of these random "picks" together, in a new variable that has 64 random picks from the $characters string group called $randomString.
这样做是从 $characters 变量中的任何字符中选择一个随机字符。然后 .= 将这些随机“选择”中的每一个的结果放在一个新变量中，该变量具有来自名为 $randomString 的 $characters 字符串组的 64 个随机选择。
