How to force type conversion to str string in php

Forced type conversion method: 1. Use strval() function, syntax "strval(variable)"; 2. Use settype() function, syntax "settype(data value, "string")"; 3. Add "(string)" before the variable of conversion type, the syntax is "(string) variable".

The operating environment of this tutorial: windows7 system, PHP7.1 version, DELL G3 computer

php will force the variable type to string (character String) There are three methods:

• Use the conversion function strval()

• Use the conversion function settype()

• Add the target type enclosed in parentheses before the variable to be converted (string)

Method 1: Use the conversion function strval ()

strval() function is used to obtain the string value of a variable. It is often used to convert data such as integer and floating point types into string types.

Syntax: strval ($var)

strval() function cannot be used for conversion of arrays or objects.

Example:

<?php
$num=3.21;
var_dump($num);
var_dump(strval($num));

$bool=TRUE;
var_dump($bool);
var_dump(strval($bool));
$bool=FALSE;
var_dump($bool);
var_dump(strval($bool));
?>

Method 2: Use the conversion function settype()

settype ( $var,$type) function is used to set variable $var to the specified data type $type. ($type can be boolean (bool), integer (int), float (double), string, array, object, null).

You only need to set the parameter $type to "string" to convert the specified variable to a string type.

Note: The settype() function will modify the original attributes; if the type is set successfully, it returns TRUE and if it fails, it returns FALSE.

Example:

<?php
header("Content-type:text/html;charset=utf-8");
$num = 3.1415;
echo &#39;原变量类型为：&#39; . gettype($num) . &#39;<br>&#39;;

$str = strval($num);
echo &#39;转换后的变量类型为：&#39; . gettype($str) . &#39;<br><br>&#39;;

$num = 31415;
echo &#39;原变量类型为：&#39; . gettype($num) . &#39;<br>&#39;;

$str = strval($num);
echo &#39;转换后的变量类型为：&#39; . gettype($str) . &#39;<br><br>&#39;;

$bool = TRUE;
echo &#39;原变量类型为：&#39; . gettype($bool) . &#39;<br>&#39;;

$str = strval($bool);
echo &#39;转换后的变量类型为：&#39; . gettype($str) . &#39;<br><br>&#39;;
?>

Method 3: Add the target type enclosed in parentheses before the variable to be converted (string )

<?php
header("Content-type:text/html;charset=utf-8");
$num = NULL;
echo &#39;原变量类型为：&#39; . gettype($num) . &#39;<br>&#39;;

$str = (string)$num;
echo &#39;转换后的变量类型为：&#39; . gettype($str) . &#39;<br><br>&#39;;

$num = 123.54;
echo &#39;原变量类型为：&#39; . gettype($num) . &#39;<br>&#39;;

$str = (string)$num;
echo &#39;转换后的变量类型为：&#39; . gettype($str) . &#39;<br><br>&#39;;

$bool = TRUE;
echo &#39;原变量类型为：&#39; . gettype($bool) . &#39;<br>&#39;;

$str = (string)$bool;
echo &#39;转换后的变量类型为：&#39; . gettype($str) . &#39;<br><br>&#39;;
?>

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