How to convert data type to string type in php

Conversion method: 1. Use strval() function, syntax "strval(data value)"; 2. Use settype() function, syntax "settype(data value, "string")"; 3. Use sprintf() function, syntax "sprintf(formatting mode, data value)".

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

php will change the data type Convert to string type

#Method 1: Use strval() function

The strval() function is used to obtain the string value of a variable.

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

Method 2: Use the settype() function

settype ($var,$type) The function is used to set the variable $var to the specified data type $type.

<?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;;
?>

The value of $type can be:

• "boolean" (or "bool" from PHP since 4.2.0)

• "integer" (or "int" since PHP 4.2.0)

• "float" ( Only available after PHP 4.2.0, "double" used in older versions is now disabled)

• "string"

• "array"

• "object"

• "null" (from PHP 4.2.0)

Method 3: Use the sprintf() function

The sprintf() function writes the formatted string into a variable.

<?php
$num=12;
var_dump($num);
$str1=sprintf("%.1f",$num);
var_dump($str1);
$str2=sprintf("%.2f",$num);
var_dump($str2);
$str3=sprintf("%.3f",$num);
var_dump($str3);
$str4=sprintf("%.4f",$num);
var_dump($str4);
?>

Description: sprintf() function

sprintf(format,arg1,arg2,arg++)

Parameters	Description
format	Required. Specifies a string and how to format variables within it. Possible format values: %% - returns a percent sign % %b - a binary number %c - the ASCII value corresponding Characters %d - Decimal number with sign (negative, 0, positive) %e - Scientific notation using lowercase (e.g. 1.2e 2) %E - Use uppercase scientific notation (e.g. 1.2E 2) %u - Decimal number without sign (greater than or equal to 0) %f - Floating point number (local setting) %F - floating point number (non-local setting) %g - shorter %e and %f %G - shorter %E and %f %o - octal number %s - string %x - hexadecimal number (lowercase letters) %X - Hexadecimal number (capital letters) Additional format value. Must be placed between % and a letter (such as %.2f): (Add or - in front of the number to define the sign of the number. By default, only negative numbers are marked, Positive numbers are not marked) ' (Specifies what to use as padding, the default is spaces. It must be used with the width specifier. For example: %'x20s (use "x" as padding)) - (Left-adjusted variable value) [0-9] (Specifies the minimum width of the variable value) .[0-9] (Specifies the number of decimal places or the maximum string Length) Note: If multiple above format values ​​are used, they must be used in the order above and cannot be disrupted.
arg1	Required. Specifies the parameters to be inserted at the first % sign in the format string.
arg2	Optional. Specifies the parameter to be inserted into the format string at the second % sign.
arg	Optional. Specifies the parameters to be inserted into the format string at the third, fourth, etc. % symbols.

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