PHP fprintf() Function
 Complete PHP String Reference
Definition and Usage
The fprintf() function writes a formatted string to a
specified output stream (example: file or database).
The arg1, arg2, ++ parameters will be inserted at percent (%)
signs in the main string. This function works "step-by-step". At the first % sign,
arg1 is inserted, at the second % sign, arg2 is inserted, etc.
The fprintf() function returns the length of the written string.
Syntax
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fprintf(stream,format,arg1,arg2,arg++)
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| Parameter |
Description |
| stream |
Required. Specifies where to write/output the string |
| format |
Required. Specifies the string and how to format the
variables in it. Possible format values:
- %% - Returns a percent sign
- %b - Binary number
- %c - The character according to the ASCII value
- %d - Signed decimal number
- %e - Scientific notation (e.g. 1.2e+2)
- %u - Unsigned decimal number
- %f - Floating-point number (local settings aware)
- %F - Floating-point number (not local settings
aware)
- %o - Octal number
- %s - String
- %x - Hexadecimal number (lowercase letters)
- %X - Hexadecimal number (uppercase letters)
Additional format values. These are placed between the % and the letter
(example %.2f):
- + (Forces both + and - in front of numbers. By
default, only negative numbers are marked)
- ' (Specifies what to use as padding. Default is space. Must be used
together with the width specifier.
Example: %'x20s (this uses "x" as padding)
- - (Left-justifies the variable value)
- [0-9] (Specifies the minimum width held of to the variable value)
- .[0-9] (Specifies the number of decimal digits or maximum
string length)
Note: If multiple additional format values are used, they must be in the same
order as above. |
| arg1 |
Required. The argument to be inserted at
the first %-sign in the format string |
| arg2 |
Optional. The argument to be inserted
at the second %-sign in the format string |
| arg++ |
Optional. The argument to be inserted
at the third, fourth, etc. %-sign in the format string |
Tips and Notes
Note: If there are more % signs than arguments, you must use placeholders. A placeholder is
inserted after the % sign,
and consists of the argument- number and "\$". See example three.
Tip: Related functions: printf(), sprintf(), vfprintf(), vprintf(),
and vsprintf().
Example 1
<?php
$str = "Hello";
$number = 123;
$file = fopen("test.txt","w");
echo fprintf($file,"%s world. Day number %u",$str,$number);
?>
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The output of the code above will be:
The following text will be written to the file "test.txt":
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Hello world. Day number 123
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Example 2
<?php
$number = 123;
$file = fopen("test.txt","w");
fprintf($file,"%f",$number);
?>
|
The following text will be written to the file "test.txt":
Example 3
Use of placeholders:
<?php
$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 2 decimals: 123.00
With no decimals: 123
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Complete PHP String Reference
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