Example
Output a formatted string:
<?php
$number = 9;
$str = "Beijing";
printf("There are %u million bicycles in %s.",$number,$str);
?>Definition and usage
The printf() function outputs a formatted string.
arg1, arg2, ++ parameters will be inserted into the main string at the percent sign (%) symbol. This function is executed step by step. At the first % sign, insert arg1, at the second % sign, arg2, and so on.
Note: If there are more % symbols than arg arguments, you must use placeholders. The placeholder is inserted after the % symbol and consists of a number and "\$". See Example 2.
Tip: Related functions: sprintf(), vprintf(), vsprintf(), fprintf() and vfprintf()
Syntax
printf(format,arg1,arg2,arg++)
| Parameters | Description |
| format | Required. Specifies a string and how to format variables within it. Possible format values:
+ (Add + or - in front of a number to define the sign of the number. By default, only Negative numbers are marked, positive numbers are not marked)
|
| arg2 | |
| arg++ | |
技术细节 返回值： 返回被输出字符串的长度。 PHP 版本： 4+ 更多实例 实例 1 使用格式值 %f： <?php
$number = 123;
printf("%f",$number);
?>Copy after login 实例 2 使用占位符： <?php
$number = 123;
printf("With 2 decimals: %1$.2f
<br>With no decimals: %1$u",$number);
?>Copy after login 实例 3 所有可能的格式值的演示： <?php
$num1 = 123456789;
$num2 = -123456789;
$char = 50; // The ASCII Character 50 is 2
// Note: The format value "%%" returns a percent sign
printf("%%b = %b <br>",$num1); // Binary number
printf("%%c = %c <br>",$char); // The ASCII Character
printf("%%d = %d <br>",$num1); // Signed decimal number
printf("%%d = %d <br>",$num2); // Signed decimal number
printf("%%e = %e <br>",$num1); // Scientific notation (lowercase)
printf("%%E = %E <br>",$num1); // Scientific notation (uppercase)
printf("%%u = %u <br>",$num1); // Unsigned decimal number (positive)
printf("%%u = %u <br>",$num2); // Unsigned decimal number (negative)
printf("%%f = %f <br>",$num1); // Floating-point number (local settings aware)
printf("%%F = %F <br>",$num1); // Floating-point number (not local settings aware)
printf("%%g = %g <br>",$num1); // Shorter of %e and %f
printf("%%G = %G <br>",$num1); // Shorter of %E and %f
printf("%%o = %o <br>",$num1); // Octal number
printf("%%s = %s <br>",$num1); // String
printf("%%x = %x <br>",$num1); // Hexadecimal number (lowercase)
printf("%%X = %X <br>",$num1); // Hexadecimal number (uppercase)
printf("%%+d = %+d <br>",$num1); // Sign specifier (positive)
printf("%%+d = %+d <br>",$num2); // Sign specifier (negative)
?>Copy after login 实例 4 字符串说明符的演示： <?php
$str1 = "Hello";
$str2 = "Hello world!";
printf("[%s]<br>",$str1);
printf("[%8s]<br>",$str1);
printf("[%-8s]<br>",$str1);
printf("[%08s]<br>",$str1);
printf("[%'*8s]<br>",$str1);
printf("[%8.8s]<br>",$str2);
?>Copy after login printf()函数优点在于可以格式化输出! printf的格式控制的完整格式： % - 0 m.n l或h 格式字符 下面对组成格式说明的各项加以说明： ①%：表示格式说明的起始符号，不可缺少。 ②-：有-表示左对齐输出，如省略表示右对齐输出。 ③0：有0表示指定空位填0,如省略表示指定空位不填。 ④m.n：m指域宽，即对应的输出项在输出设备上所占的字符数。N指精度。用于说明输出的实型数的小数位数。为指定n时，隐含的精度为n=6位。 ⑤l或h:l对整型指long型，对实型指double型。h用于将整型的格式字符修正为short型。 The above is the detailed content of PHP outputs formatted string function printf(). For more information, please follow other related articles on the PHP Chinese website!
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