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  • is_string()

    (PHP 4, PHP 5, PHP 7)

    检测变量是否是字符串

    描述

    is_string(mixed $var): bool

    如果$var是string则返回TRUE,否则返回FALSE

    参见is_bool()、is_int()、is_integer()、is_float()、is_real()、is_object()和is_array()。

    Using is_string() on an object will always return false (even with __toString()).
    <?php
    class B {
     public function __toString() {
      return "Instances of B() can be treated as a strings!\n";
     }
    } 
    $b = new B();
    print($b); //Instances of B() can be treated as a strings!
    print(is_string($b) ? 'true' : 'false'); //false
    ?>
    
    As noted earlier, is_string() returns false on an object that has a __toString() method. Here is a simple way to do a check that will work:
    <?php
    // determine if the passed argument can be treated like a string.
    function is_stringy($text) {
      return (is_string($text) || (is_object($text) && method_exists($text, '__toString' ));
    }

    上篇:is_scalar()

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