PHP fprintf () function
Examples
Write some text into a text file named "test.txt" is:
$number = 9;
$str = "Beijing";
$file = fopen("test.txt","w");
echo fprintf($file,"There are %u million bicycles in %s.",$number,$str);
?>
The code above will output:
The following text will be written to the file "test.txt":
Definition and Usage
fprintf () function to format string is written to the specified output stream (for example: file or database).
arg1, arg2, ++ parameters will be inserted into the main string percent sign (%) sign at. This function is performed on. In the first% sign at the insertion arg1, symbol% in the second place, insert arg2, and so on.
Note: If the% symbol than arg parameter, you must use placeholders.After placeholder is inserted into the% symbol, numbers and "\ $" component. See Example 2.
Tip: correlation function: the printf () , sprintf () , vprintf, () , vsprintf () and vfprintf ()
grammar
参数 | 描述 |
---|---|
stream | 必需。规定在哪里写入/输出字符串。 |
format | 必需。规定字符串以及如何格式化其中的变量。 可能的格式值:
附加的格式值。必需放置在 % 和字母之间(例如 %.2f):
注释:如果使用多个上述的格式值,它们必须按照上面的顺序进行使用,不能打乱。 |
arg1 | 必需。规定插到 format 字符串中第一个 % 符号处的参数。 |
arg2 | 可选。规定插到 format 字符串中第二个 % 符号处的参数。 |
arg++ | 可选。规定插到 format 字符串中第三、四等等 % 符号处的参数。 |
technical details
return value: | Returns the length of the string to be written. |
---|---|
PHP version: | 5+ |
More examples
Example 1
Some text is written to the file:
$number = 123;
$file = fopen("test.txt","w");
fprintf($file,"%f",$number);
?>
The following text will be written to the file "test.txt":
Example 2
Use placeholders:
$number = 123;
$file = fopen("test.txt","w");
fprintf($file,"With 2 decimals: %1$.2f
nWith no decimals: %1$u",$number);
?>
The following text will be written to the file "test.txt":
With no decimals: 123
Example 3
Using printf () to demonstrate the value of all the possible formats:
$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)
?>
Running instance »
PHP String Reference