首页 | 新闻 | 交流 | 问吧 | 文档 | 手册 | 下载 | 博客

testphp

作者:  时间: 2011-06-01

<?php
$a_bool
= TRUE; // a boolean
$a_str = "foo"; // a string
$a_str2 = 'foo'; // a string
$an_int = 12; // an integer

echo gettype($a_bool);
// prints out: boolean
echo gettype($a_str); // prints out: string

// If this is an integer, increment it by four
if (is_int($an_int)) {
$an_int
+= 4;
}

// If $bool is a string, print it out
// (does not print out anything)
if (is_string($a_bool)) {
echo
"String: $a_bool";
}
?>

变量的类型通常不是由程序员设定的,确切地说,是由 PHP 根据该变量使用的上下文在运行时决定的。

Note: 如果想查看某个表达式的值和类型,用 var_dump()

如果只是想得到一个易读懂的类型的表达方式用于调试,用 gettype()。要查看某个类型,不要gettype(),而用 is_type 函数。以下是一些范例:

<?php
$a_bool = TRUE; // a boolean
$a_str = "foo"; // a string
$a_str2 = 'foo'; // a string
$an_int = 12; // an integer

echo gettype($a_bool); // prints out: boolean
echo gettype($a_str); // prints out: string

// If this is an integer, increment it by four

if (is_int($an_int)) {
$an_int += 4;
}

// If $bool is a string, print it out
// (does not print out anything)

if (is_string($a_bool)) {
echo "String: $a_bool";
}
?>
<?php
$a_bool = TRUE;   // a boolean
$a_str  = "foo";  // a string
$a_str2 = 'foo';  // a string
$an_int = 12;     // an integer

echo gettype($a_bool); // prints out:  boolean
echo gettype($a_str);  // prints out:  string

// If this is an integer, increment it by four
if (is_int($an_int)) {
    $an_int += 4;
}

// If $bool is a string, print it out
// (does not print out anything)
View Code
<?php
$a_bool
= TRUE; // a boolean
$a_str = "foo"; // a string
$a_str2 = 'foo'; // a string
$an_int = 12; // an integer

echo gettype($a_bool);
// prints out: boolean
echo gettype($a_str); // prints out: string

// If this is an integer, increment it by four
if (is_int($an_int)) {
$an_int
+= 4;
}

// If $bool is a string, print it out
// (does not print out anything)
if (is_string($a_bool)) {
echo
"String: $a_bool";
}
?>
if (is_string($a_bool)) { echo "String: $a_bool"; } ?>
<?php
$a_bool = TRUE;   // a boolean
$a_str  = "foo";  // a string
$a_str2 = 'foo';  // a string
$an_int = 12;     // an integer

echo gettype($a_bool); // prints out:  boolean
echo gettype($a_str);  // prints out:  string

// If this is an integer, increment it by four
if (is_int($an_int)) {
    $an_int += 4;
}

// If $bool is a string, print it out
// (does not print out anything)
if (is_string($a_bool)) {
    echo "String: $a_bool";
}
?>
<?php
$a_bool = TRUE;   // a boolean
$a_str  = "foo";  // a string
$a_str2 = 'foo';  // a string
$an_int = 12;     // an integer

echo gettype($a_bool); // prints out:  boolean
echo gettype($a_str);  // prints out:  string

// If this is an integer, increment it by four
if (is_int($an_int)) {
    $an_int += 4;
}

// If $bool is a string, print it out
// (does not print out anything)
if (is_string($a_bool)) {
    echo "String: $a_bool";
}
?>