PHP数据类型之间的强制转换

$bool1=TRUE;
$str3=(string)$bool1;

echo "<hr>";
echo var_dump($str3),"<br>";

$bool1=FALSE;
$str3=(string)$bool1;

echo var_dump($str3),"<br>";

<?php 
//1.实型数据强制转换为整型数据
$float1=2.7;
$int1=(int)$float1;


echo var_dump($int1),"<br>";


//2.整型数据强制转换为实型数据
$int2=3;
$float2=(float)$int2;

echo "<hr>";
echo var_dump($float2),"<br>";


//3.整型数据强制转换为字符串数据
$int3=4;
$str1=(string)$int2;

echo "<hr>";
echo var_dump($str1),"<br>";

//4.整型数据强制转换为字符串数据
$float3=4.7;
$str2=(string)$float3;

echo "<hr>";
echo var_dump($str2),"<br>";


//5.布尔型数据强制转换为字符串数据
$bool1=TRUE;
$str3=(string)$bool1;

echo "<hr>";
echo var_dump($str3),"<br>";

$bool1=FALSE;
$str3=(string)$bool1;

echo var_dump($str3),"<br>";

//6.布尔型数据强制转换为整型数据
$bool2=TRUE;
$str4=(string)$bool2;

echo "<hr>";
echo var_dump($str4),"<br>";

//7.整型数据强制转换为布尔型数据 (只有是0时，返回flase，其他都返回true)
$int4=2;
$bool3=(bool)$int4;

echo "<hr>";
echo var_dump($bool3),"<br>";

$int4=-2;
$bool3=(bool)$int4;

echo var_dump($bool3),"<br>";


$int4=0;
$bool3=(bool)$int4;

echo var_dump($bool3),"<br>"; //返回false


//8.字符串型数据强制转换为布尔型数据 (只有是"0"和空""时，返回flase，其他都返回true)
$str5="1";
$bool4=(bool)$str5;

echo "<hr>";
echo var_dump($bool4),"<br>";

$str5="0";
$bool4=(bool)$str5;

echo var_dump($bool4),"<br>"; //返回false

$str5="00";
$bool4=(bool)$str5;

echo var_dump($bool4),"<br>"; //返回true

$str5="HELLO!";
$bool4=(bool)$str5;

echo var_dump($bool4),"<br>";


$str5="0HELLO!";
$bool4=(bool)$str5;

echo var_dump($bool4),"<br>";

$str5="";
$bool4=(bool)$str5;

echo var_dump($bool4),"<br>"; //返回false

$str5=" ";
$bool4=(bool)$str5;


$str5="FLASE";
$bool4=(bool)$str5;

echo var_dump($bool4),"<br>"; //返回true
 ?>