With printf() and sprintf() functions, escape character is not backslash '\' but rather '%'.
Ie. to print '%' character you need to escape it with itself:
<?php
printf('%%%s%%', 'koko'); #output: '%koko%'
?>
(PHP 4, PHP 5, PHP 7, PHP 8)
sprintf — Biçemli bir dizge döndürür
biçem
dizgesiyle biçemlenerek üretilmiş bir dizge
döndürür.
biçem
Biçem dizgesi sıfır veya daha fazla yönergeden oluşur:
doğrudan sonuca kopyalanmış sıradan karakterler (%
hariç) ve dönüşüm belirtimleri, her biri kendi
bağımsız değişkeninin getirilmesiyle sonuçlanır.
Bir dönüşüm belirtiminin sözdizimi:
%[degnum$][seçenekler][genişlik][.hassasiyet]belirteç
.
Ardına bir dolar imi $
konmuş bir tamsayı;
dönüşümde ele alınacak bağımsız değişken sayısını belirler.
Seçenek | Açıklama |
---|---|
- |
Verilen alan genişliğinde sola dayalı; Sağa dayalılık öntanımlıdır. |
+ |
Pozitif sayıların önüne artı imi konur; Öntanımlı olarak sadece negatif sayılara eksi imi konur. |
(boşluk) |
Sonuca boşluklarla dolgu yapar. Bu öntanımlıdır. |
0 |
Sayılar sadece soldan sıfırla doldurulur.
s belirteçleri ile sağ taraf da sıfırla doldurulur.
|
' (krk) |
Sonuca (krk) karakteri ile dolgu yapılır. |
Bu dönüşümün kaç karakterle sonuçlanacağının belirtildiği tamsayı veya
*
. *
kullanılmışsa, genişlik,
belirtici tarafından biçimlendirilmiş değerden önce ek bir tamsayı
değeri olarak sağlanır.
Bir nokta .
ve ardından anlamı belirtece bağlı olan
seçimlik bir tamsayı veya *
:
e
, E
,
f
ve F
belirteçleri için: ondalık noktadan sonra yazdırılacak rakam sayısı
(6 öntanımlıdır)
g
ve G
,
h
ve H
belirteçleri için: yazdırılacak maksimum anlamlı basamak sayısı.
s
belirteci için: dizeye azami karakter sınırı
koyan bir kesme noktası gibi davranır.
Bilginize: Nokta, hassasiyet için açık bir değer olmadan belirtilirse, 0 varsayılır.
*
kullanılmışsa, genişlik, belirtici tarafından biçimlendirilmiş değerden önce ek bir tamsayı değeri olarak sağlanır.
Belirteç | Açıklama |
---|---|
% |
Yüzde karakteri. Değer gerekmez. |
b |
Değer bir tamsayı olarak ele alınır ve ikil bir sayı olarak gösterilir. |
c |
Değer bir tamsayı olarak ele alınır ve ASCII bir karakter olarak gösterilir. |
d |
Değer bir tamsayı olarak ele alınır ve (işaretli) bir ondalık sayı olarak gösterilir. |
e |
Değer bilimsel bir gösterim (örn. 1.2e+2) olarak ele alınır. Hassasiyet belirteci,ondalık noktadan sonraki basamakların sayısını ifade eder. |
E |
e belirteci gibi, farklı olarak büyük harf kullanır
(örn. 1.2E+2).
|
f |
Değer kayan noktalı sayı olarak ele alınır ve kayan noktalı sayı olarak gösterilir (yerele uygun). |
F |
Değer kayan noktalı sayı olarak ele alınır ve kayan noktalı sayı olarak gösterilir (yerele bakmaz) PHP 5.0.3 ve sonrasında kullanılabilir. |
g |
Genel biçem. P sıfırdan farklı hassasiyet olsun, hassasiyet verilmemişse 6, hassasiyet sıfır ise 1 olsun. E tarzındaki dönüşümün üssü X ise: P > X ≥ −4 ise, dönüşüm f tarzı ve hassasiyet P − (X + 1) olur. Aksi takdirde, dönüşüm e tarzı ve hassasiyet P − 1 olur. |
G |
g gibidir fakat
E ve f kullanır.
|
h |
g gibidir fakat F kullanır.
PHP 8.0.0 ve sonrasında kullanılabilir.
|
H |
g gibidir fakat
E ve F kullanır.
PHP 8.0.0 ve sonrasında kullanılabilir.
|
o |
Değer bir tamsayı olarak ele alınır ve sekizlik bir sayı olarak gösterilir. |
s |
Değer bir dizge olarak ele alınır ve gösterilir. |
u |
Değer bir tamsayı olarak ele alınır ve işaretsiz bir ondalık sayı olarak gösterilir. |
x |
Değer bir tamsayı olarak ele alınır ve onaltılık bir sayı olarak gösterilir (küçük harfli). |
X |
Değer bir tamsayı olarak ele alınır ve onaltılık bir sayı olarak gösterilir (büyük harfli). |
c
tür belirteci dolguyu ve genişliği yoksayar.
Karakter başına birden fazla bayt gerektiren karakter kümeleriyle dizge ve genişlik belirteçlerini bir arada kullanmaya çalışmak, beklenmeyen sonuçlar verebilir
Değişkenler, belirteç için uygun bir türe zorlanacaktır:
Tür | Belirteçler |
---|---|
string | s |
int |
d ,
u ,
c ,
o ,
x ,
X ,
b
|
double |
e ,
E ,
f ,
F ,
g ,
G ,
h ,
H
|
değerler
biçem
dizgesine göre biçemlendirilerek üretilen bir
dizge döner.
PHP 8.0.0 ve sonrasında, bağımsız değişken sayısı sıfırsa
ValueError oluşuyor. PHP 8.0.0 öncesinde bunun
yerine bir E_WARNING
uyarısı verilirdi.
PHP 8.0.0 ve sonrasında, [width]
(genişlik) sıfırdan
küçükse veya PHP_INT_MAX
'tan büyükse bir
ValueError oluşuyor. PHP 8.0.0 öncesinde, bir
E_WARNING
uyarısı verilirdi.
PHP 8.0.0 ve sonrasında, [precision]
(hassasiyet)
sıfırdan küçükse veya PHP_INT_MAX
'tan büyükse bir
ValueError oluşuyor. PHP 8.0.0 öncesinde, bir
E_WARNING
uyarısı verilirdi.
PHP 8.0.0 ve sonrasında, gereğinden daha az bağımsız değişken verildiğinde
bir ArgumentCountError oluşuyor. PHP 8.0.0 öncesinde,
bir E_WARNING
uyarısı verilirdi.
Sürüm: | Açıklama |
---|---|
8.0.0 |
Bu işlev başarısızlık durumunda artık false döndürmüyor.
|
8.0.0 |
Bağımsız değişken sayısı sıfırsa ValueError oluşuyor. Evvelce bunun yerine bir E_WARNING uyarısı verilirdi.
|
8.0.0 |
[width] (genişlik) sıfırdan küçükse veya
PHP_INT_MAX 'tan büyükse bir
ValueError oluşuyor;
evvelce bir E_WARNING uyarısı verilirdi.
|
8.0.0 |
[precision] (hassasiyet) sıfırdan küçükse veya
PHP_INT_MAX 'tan büyükse bir
ValueError oluşuyor;
evvelce bir E_WARNING uyarısı verilirdi.
|
8.0.0 |
Gereğinden daha az bağımsız değişken verildiğinde bir
ArgumentCountError oluşuyor; evvelce bir
E_WARNING uyarısı verilirdi.
|
Örnek 1 - Bağımsız değişken takaslama
Biçem dizgesi bağımsız değişken numaralama/takaslama destekliyor.
<?php
$num = 5;
$location = 'tree';
$format = 'There are %d monkeys in the %s';
echo sprintf($format, $num, $location);
?>
Yukarıdaki örneğin çıktısı:
There are 5 monkeys in the tree
Biçem dizgesini ayrı bir dosyada oluşturduğunuzu varsayalım. Çünkü ona u12a uygulamak ve yeniden yazmak istiyoruz:
<?php
$format = 'The %s contains %d monkeys';
echo sprintf($format, $num, $location);
?>
Artık bir sorunumuz var. Biçem dizgesindeki belirteçlerin sırası koddaki bağımsız değişken sırasına uygun değil. Koda dokunmak istemiyoruz, biçem dizgesindeki belirteçler koda uyum sağlasın istiyoruz. Bu durumda biçem dizgesini şöyle yararız:
<?php
$format = 'The %2$s contains %1$d monkeys';
echo sprintf($format, $num, $location);
?>
Belirteçlerin bir yararı da koda bağımsız değişken eklemeksizin belirteçlerin yinelenebilmesidir.
<?php
$format = 'The %2$s contains %1$d monkeys.
That\'s a nice %2$s full of %1$d monkeys.';
echo sprintf($format, $num, $location);
?>
Bağımsız değişken takaslama yapılırken n$
konum belirteci hemen yüzde iminden
(%
) sonra, diğer belirteçlerden önce gelmelidir;
aşağıdaki gibi:
Örnek 2 - Dolgu karakteri belirtmek
<?php
echo sprintf("%'.9d\n", 123);
echo sprintf("%'.09d\n", 123);
?>
Yukarıdaki örneğin çıktısı:
+......123 +000000123
Örnek 3 - Konum belirteçlerini diğer belirteçlerle birlikte kullanmak
<?php
+$format = 'The %2$s contains %1$04d monkeys';
+echo sprintf($format, $num, $location);
?>
Yukarıdaki örneğin çıktısı:
The tree contains 0005 monkeys
Örnek 4 - sprintf() ve sıfır dolgulu tamsayılar
<?php
$isodate = sprintf("%04d-%02d-%02d", $year, $month, $day);
?>
Örnek 5 - sprintf() ve para biçemleme
<?php
$money1 = 68.75;
$money2 = 54.35;
$money = $money1 + $money2;
echo $money;
echo "\n";
$formatted = sprintf("%01.2f", $money);
echo $formatted;
?>
Yukarıdaki örneğin çıktısı:
123.1 123.10
Örnek 6 - sprintf() ve bilimsel gösterim
<?php
$number = 362525200;
echo sprintf("%.3e", $number);
?>
Yukarıdaki örneğin çıktısı:
3.625e+8
With printf() and sprintf() functions, escape character is not backslash '\' but rather '%'.
Ie. to print '%' character you need to escape it with itself:
<?php
printf('%%%s%%', 'koko'); #output: '%koko%'
?>
1. A plus sign ('+') means put a '+' before positive numbers while a minus sign ('-') means left justify. The documentation incorrectly states that they are interchangeable. They produce unique results that can be combined:
<?php
echo sprintf ("|%+4d|%+4d|\n", 1, -1);
echo sprintf ("|%-4d|%-4d|\n", 1, -1);
echo sprintf ("|%+-4d|%+-4d|\n", 1, -1);
?>
outputs:
| +1| -1|
|1 |-1 |
|+1 |-1 |
2. Padding with a '0' is different than padding with other characters. Zeros will only be added at the front of a number, after any sign. Other characters will be added before the sign, or after the number:
<?php
echo sprintf ("|%04d|\n", -2);
echo sprintf ("|%':4d|\n", -2);
echo sprintf ("|%-':4d|\n", -2);
// Specifying both "-" and "0" creates a conflict with unexpected results:
echo sprintf ("|%-04d|\n", -2);
// Padding with other digits behaves like other non-zero characters:
echo sprintf ("|%-'14d|\n", -2);
echo sprintf ("|%-'04d|\n", -2);
?>
outputs:
|-002|
|::-2|
|-2::|
|-2 |
|-211|
|-2 |
Here is how to print a floating point number with 16 significant digits regardless of magnitude:
<?php
$result = sprintf(sprintf('%%.%dF', max(15 - floor(log10($value)), 0)), $value);
?>
This works more reliably than doing something like sprintf('%.15F', $value) as the latter may cut off significant digits for very small numbers, or prints bogus digits (meaning extra digits beyond what can reliably be represented in a floating point number) for very large numbers.
There are already some comments on using sprintf to force leading leading zeros but the examples only include integers. I needed leading zeros on floating point numbers and was surprised that it didn't work as expected.
Example:
<?php
sprintf('%02d', 1);
?>
This will result in 01. However, trying the same for a float with precision doesn't work:
<?php
sprintf('%02.2f', 1);
?>
Yields 1.00.
This threw me a little off. To get the desired result, one needs to add the precision (2) and the length of the decimal seperator "." (1). So the correct pattern would be
<?php
sprintf('%05.2f', 1);
?>
Output: 01.00
Please see http://stackoverflow.com/a/28739819/413531 for a more detailed explanation.
Here's a clean, working version of functions to allow using named arguments instead of numeric ones. ex: instead of sprintf('%1$s', 'Joe');, we can use sprintf('%name$s', array('name' => 'Joe'));. I've provided 2 different versions: the first uses the php-like syntax (ex: %name$s), while the second uses the python syntax (ex: %(name)s).
<?php
/**
* version of sprintf for cases where named arguments are desired (php syntax)
*
* with sprintf: sprintf('second: %2$s ; first: %1$s', '1st', '2nd');
*
* with sprintfn: sprintfn('second: %second$s ; first: %first$s', array(
* 'first' => '1st',
* 'second'=> '2nd'
* ));
*
* @param string $format sprintf format string, with any number of named arguments
* @param array $args array of [ 'arg_name' => 'arg value', ... ] replacements to be made
* @return string|false result of sprintf call, or bool false on error
*/
function sprintfn ($format, array $args = array()) {
// map of argument names to their corresponding sprintf numeric argument value
$arg_nums = array_slice(array_flip(array_keys(array(0 => 0) + $args)), 1);
// find the next named argument. each search starts at the end of the previous replacement.
for ($pos = 0; preg_match('/(?<=%)([a-zA-Z_]\w*)(?=\$)/', $format, $match, PREG_OFFSET_CAPTURE, $pos);) {
$arg_pos = $match[0][1];
$arg_len = strlen($match[0][0]);
$arg_key = $match[1][0];
// programmer did not supply a value for the named argument found in the format string
if (! array_key_exists($arg_key, $arg_nums)) {
user_error("sprintfn(): Missing argument '${arg_key}'", E_USER_WARNING);
return false;
}
// replace the named argument with the corresponding numeric one
$format = substr_replace($format, $replace = $arg_nums[$arg_key], $arg_pos, $arg_len);
$pos = $arg_pos + strlen($replace); // skip to end of replacement for next iteration
}
return vsprintf($format, array_values($args));
}
/**
* version of sprintf for cases where named arguments are desired (python syntax)
*
* with sprintf: sprintf('second: %2$s ; first: %1$s', '1st', '2nd');
*
* with sprintfn: sprintfn('second: %(second)s ; first: %(first)s', array(
* 'first' => '1st',
* 'second'=> '2nd'
* ));
*
* @param string $format sprintf format string, with any number of named arguments
* @param array $args array of [ 'arg_name' => 'arg value', ... ] replacements to be made
* @return string|false result of sprintf call, or bool false on error
*/
function sprintfn ($format, array $args = array()) {
// map of argument names to their corresponding sprintf numeric argument value
$arg_nums = array_slice(array_flip(array_keys(array(0 => 0) + $args)), 1);
// find the next named argument. each search starts at the end of the previous replacement.
for ($pos = 0; preg_match('/(?<=%)\(([a-zA-Z_]\w*)\)/', $format, $match, PREG_OFFSET_CAPTURE, $pos);) {
$arg_pos = $match[0][1];
$arg_len = strlen($match[0][0]);
$arg_key = $match[1][0];
// programmer did not supply a value for the named argument found in the format string
if (! array_key_exists($arg_key, $arg_nums)) {
user_error("sprintfn(): Missing argument '${arg_key}'", E_USER_WARNING);
return false;
}
// replace the named argument with the corresponding numeric one
$format = substr_replace($format, $replace = $arg_nums[$arg_key] . '$', $arg_pos, $arg_len);
$pos = $arg_pos + strlen($replace); // skip to end of replacement for next iteration
}
return vsprintf($format, array_values($args));
}
?>
Be cafeful while trying to refactor longer strings with repeated placeholders like
sprintf("Hi %s. Your name is %s", $name, $name);
to use argument numbering:
sprintf("Hi %1$s. Your name is %1$s", $name);
This will nuke you at **runtime**, because of `$s` thing being handled as variable. If you got no $s for substitution, notice will be thrown.
The solution is to use single quotes to prevent variable substitution in string:
sprintf('Hi %1$s. Your name is %1$s', $name);
If you need variable substitution, then you'd need to split your string to keep it in single quotes:
sprintf("Hi " . '%1$s' . ". Your {$variable} is " . '%1$s', $name);
I had a nightmare trying to find the two's complement of a 32 bit number.
I got this from http://www.webmasterworld.com/forum88/13334.htm (credit where credit is due... =P )
Quote: ...find out the 2's complement of any number, which is -(pow(2, n) - N) where n is the number of bits and N is the number for which to find out its 2's complement.
This worked magic for me... previously I was trying to use
sprintf ("%b",$32BitDecimal);
But it always returned 10000000000000000000000 when the $32BitDecimal value got above 2,000,000,000.
This -(pow(2, n) - N)
Worked remarkably well and was very accurate.
Hope this helps someone fighting with two's complement in PHP.
Just to elaborate on downright's point about different meanings for %f, it appears the behavior changed significantly as of 4.3.7, rather than just being different on different platforms. Previously, the width specifier gave the number of characters allowed BEFORE the decimal. Now, the width specifier gives the TOTAL number of characters. (This is in line with the semantics of printf() in other languages.) See bugs #28633 and #29286 for more details.
The old "monkey" example which helped me a lot has sadly disappeared.
I'll Re-post it in comment as a memory.
<?php
$n = 43951789;
$u = -43951789;
$c = 65; // ASCII 65 is 'A'
// notice the double %%, this prints a literal '%' character
printf("%%b = '%b'\n", $n); // binary representation
printf("%%c = '%c'\n", $c); // print the ascii character, same as chr() function
printf("%%d = '%d'\n", $n); // standard integer representation
printf("%%e = '%e'\n", $n); // scientific notation
printf("%%u = '%u'\n", $n); // unsigned integer representation of a positive integer
printf("%%u = '%u'\n", $u); // unsigned integer representation of a negative integer
printf("%%f = '%f'\n", $n); // floating point representation
printf("%%o = '%o'\n", $n); // octal representation
printf("%%s = '%s'\n", $n); // string representation
printf("%%x = '%x'\n", $n); // hexadecimal representation (lower-case)
printf("%%X = '%X'\n", $n); // hexadecimal representation (upper-case)
printf("%%+d = '%+d'\n", $n); // sign specifier on a positive integer
printf("%%+d = '%+d'\n", $u); // sign specifier on a negative integer
/*
%b = '10100111101010011010101101'
%c = 'A'
%d = '43951789'
%e = '4.395179e+7'
%u = '43951789'
%u = '18446744073665599827'
%f = '43951789.000000'
%o = '247523255'
%s = '43951789'
%x = '29ea6ad'
%X = '29EA6AD'
%+d = '+43951789'
%+d = '-43951789'
*/
$s = 'monkey';
$t = 'many monkeys';
printf("[%s]\n", $s); // standard string output
printf("[%10s]\n", $s); // right-justification with spaces
printf("[%-10s]\n", $s); // left-justification with spaces
printf("[%010s]\n", $s); // zero-padding works on strings too
printf("[%'#10s]\n", $s); // use the custom padding character '#'
printf("[%10.10s]\n", $t); // left-justification but with a cutoff of 10 characters
/*
[monkey]
[ monkey]
[monkey ]
[0000monkey]
[####monkey]
[many monke]
*/
?>
A more complete and working version of mb_sprintf and mb_vsprintf. It should work with any "ASCII preserving" encoding such as UTF-8 and all the ISO-8859 charsets. It handles sign, padding, alignment, width and precision. Argument swapping is not handled.
<?php
if (!function_exists('mb_sprintf')) {
function mb_sprintf($format) {
$argv = func_get_args() ;
array_shift($argv) ;
return mb_vsprintf($format, $argv) ;
}
}
if (!function_exists('mb_vsprintf')) {
/**
* Works with all encodings in format and arguments.
* Supported: Sign, padding, alignment, width and precision.
* Not supported: Argument swapping.
*/
function mb_vsprintf($format, $argv, $encoding=null) {
if (is_null($encoding))
$encoding = mb_internal_encoding();
// Use UTF-8 in the format so we can use the u flag in preg_split
$format = mb_convert_encoding($format, 'UTF-8', $encoding);
$newformat = ""; // build a new format in UTF-8
$newargv = array(); // unhandled args in unchanged encoding
while ($format !== "") {
// Split the format in two parts: $pre and $post by the first %-directive
// We get also the matched groups
list ($pre, $sign, $filler, $align, $size, $precision, $type, $post) =
preg_split("!\%(\+?)('.|[0 ]|)(-?)([1-9][0-9]*|)(\.[1-9][0-9]*|)([%a-zA-Z])!u",
$format, 2, PREG_SPLIT_DELIM_CAPTURE) ;
$newformat .= mb_convert_encoding($pre, $encoding, 'UTF-8');
if ($type == '') {
// didn't match. do nothing. this is the last iteration.
}
elseif ($type == '%') {
// an escaped %
$newformat .= '%%';
}
elseif ($type == 's') {
$arg = array_shift($argv);
$arg = mb_convert_encoding($arg, 'UTF-8', $encoding);
$padding_pre = '';
$padding_post = '';
// truncate $arg
if ($precision !== '') {
$precision = intval(substr($precision,1));
if ($precision > 0 && mb_strlen($arg,$encoding) > $precision)
$arg = mb_substr($precision,0,$precision,$encoding);
}
// define padding
if ($size > 0) {
$arglen = mb_strlen($arg, $encoding);
if ($arglen < $size) {
if($filler==='')
$filler = ' ';
if ($align == '-')
$padding_post = str_repeat($filler, $size - $arglen);
else
$padding_pre = str_repeat($filler, $size - $arglen);
}
}
// escape % and pass it forward
$newformat .= $padding_pre . str_replace('%', '%%', $arg) . $padding_post;
}
else {
// another type, pass forward
$newformat .= "%$sign$filler$align$size$precision$type";
$newargv[] = array_shift($argv);
}
$format = strval($post);
}
// Convert new format back from UTF-8 to the original encoding
$newformat = mb_convert_encoding($newformat, $encoding, 'UTF-8');
return vsprintf($newformat, $newargv);
}
}
?>
If you use the default padding specifier (a space) and then print it to HTML, you will notice that HTML does not display the multiple spaces correctly. This is because any sequence of white-space is treated as a single space.
To overcome this, I wrote a simple function that replaces all the spaces in the string returned by sprintf() with the character entity reference " " to achieve non-breaking space in strings returned by sprintf()
<?php
//Here is the function:
function sprintf_nbsp() {
$args = func_get_args();
return str_replace(' ', ' ', vsprintf(array_shift($args), array_values($args)));
}
//Usage (exactly like sprintf):
$format = 'The %d monkeys are attacking the [%10s]!';
$str = sprintf_nbsp($format, 15, 'zoo');
echo $str;
?>
The above example will output:
The 15 monkeys are attacking the [ zoo]!
<?php
//The variation that prints the string instead of returning it:
function printf_nbsp() {
$args = func_get_args();
echo str_replace(' ', ' ', vsprintf(array_shift($args), array_values($args)));
}
?>
To jrust at rustyparts.com, note that if you're using a double-quoted string and *don't* escape the dollar sign with a backslash, $s and $d will be interpreted as variable references. The backslash isn't part of the format specifier itself but you do need to include it when you write the format string (unless you use single quotes).
If you want to convert a decimal (integer) number into constant length binary number in lets say 9 bits, use this:
$binary = sprintf('%08b', $number );
for example:
<?php
$bin = sprintf('%08b',511 );
echo $bin."\n";
?>
would output 111111111
And 2 would output 00000010
I know the leading zeros are useful to me, perhaps they are to someone else too.
Just a reminder for beginners : example 6 'printf("[%10s]\n", $s);' only works (that is, shows out the spaces) if you put the html '<pre></pre>' tags ( head-scraping time saver ;-).
Using argument swapping in sprintf() with gettext: Let's say you've written the following script:
<?php
$var = sprintf(gettext("The %2\$s contains %1\$d monkeys"), 2, "cage");
?>
Now you run xgettext in order to generate a .po file. The .po file will then look like this:
#: file.php:9
#, ycp-format
msgid "The %2\\$s contains %1\\$d monkeys"
msgstr ""
Notice how an extra backslash has been added by xgettext.
Once you've translated the string, you must remove all backslashes from the ID string as well as the translation, so the po file will look like this:
#: file.php:9
#, ycp-format
msgid "The %2$s contains %1$d monkeys"
msgstr "Der er %1$d aber i %2$s"
Now run msgfmt to generate the .mo file, restart Apache to remove the gettext cache if necessary, and you're off.
If you use argument numbering, then format specifications with the same number get the same argument; this can save repeating the argument in the function call.
<?php
$pattern = '%1$s %1$\'#10s %1$s!';
printf($pattern, "badgers");
?>
$format = 'There are %1$d monkeys in the %s and %s ';
printf($format, 100, 'Chennai', 'Bangalore');
Expecting to output
"There are 100 monkeys in the Chennai and bangalore"
But, this will output
"There are 100 monkeys in the 100 and Chennai"
Because, the second and Third specifiers takes 1rst and 2nd arguments. Because it is not assigned with any arguments.
And continuing on the same theme of a key-based sprintf...
I'm roughly (I can see a couple cases where it comes out wierd) copying the syntax of Python's string formatting with a dictionary. The improvement over the several past attempts is that this one still respects all of the formating options, as you can see in my example.
And the error handling is really crappy (just an echo). I just threw this together so do with it what you will. =]
<?php
function sprintf_array($string, $array)
{
$keys = array_keys($array);
$keysmap = array_flip($keys);
$values = array_values($array);
while (preg_match('/%\(([a-zA-Z0-9_ -]+)\)/', $string, $m))
{
if (!isset($keysmap[$m[1]]))
{
echo "No key $m[1]\n";
return false;
}
$string = str_replace($m[0], '%' . ($keysmap[$m[1]] + 1) . '$', $string);
}
array_unshift($values, $string);
var_dump($values);
return call_user_func_array('sprintf', $values);
}
echo sprintf_array('4 digit padded number: %(num)04d ', array('num' => 42));
?>
Cheers!
Encoding and decoding IP adress to format: 1A2B3C4D (mysql column: char(8) )
<?php
function encode_ip($dotquad_ip)
{
$ip_sep = explode('.', $dotquad_ip);
return sprintf('%02x%02x%02x%02x', $ip_sep[0], $ip_sep[1], $ip_sep[2], $ip_sep[3]);
}
function decode_ip($int_ip)
{
$hexipbang = explode('.', chunk_split($int_ip, 2, '.'));
return hexdec($hexipbang[0]). '.' . hexdec($hexipbang[1]) . '.' . hexdec($hexipbang[2]) . '.' . hexdec($hexipbang[3]);
}
?>
I couldn't find what should be a WARNING in the documentation above, that if you have more specifiers than variables to match them sprintf returns NOTHING. This fact, IMHO, should also be noted under return values.
Note that when using the argument swapping, you MUST number every argument, otherwise sprintf gets confused. This only happens if you use number arguments first, then switch to a non-numbered, and then back to a numbered one.
<?php
$sql = sprintf( "select * from %1\$s left join %2\$s on( %1\$s.id = %2\$s.midpoint ) where %1\$s.name like '%%%s%%' and %2\$s.tagname is not null", "table1", "table2", "bob" );
// Wont work:
// Sprintf will complain about not enough arguments.
$sql = sprintf( "select * from %1\$s left join %2\$s on( %1\$s.id = %2\$s.midpoint ) where %1\$s.name like '%%%3\$s%%' and %2\$s.tagname is not null", "table1", "table2", "bob" );
// Will work: note the %3\$s
?>
Note that when using a sign specifier, the number zero is considered positive and a "+" sign will be prepended to it.
<?php
printf('%+d', 0); // +0
?>
Just wanted to add that to get the remaining text from the string, you need to add the following as a variable in your scanf
%[ -~]
Example:
sscanf($sql, "[%d,%d]%[ -~]", $sheet_id, $column, $remaining_sql);
Here is an example how alignment, padding and precision specifier can be used to print formatted list of items:
<?php
$out = "The Books\n";
$books = array("Book 1", "Book 2", "Book 3");
$pages = array("123 pages ", "234 pages", "345 pages");
for ($i = 0; $i < count($books); $i++) {
$out .= sprintf("%'.-20s%'.7.4s\n", $books[$i], $pages[$i]);
}
echo $out;
// Outputs:
//
// The Books
// Book 1.................123
// Book 2.................234
// Book 3.................345
?>
Be careful if you use the %f modifier to round decimal numbers as it (starting from 4.3.10) will no longer produce a float number if you set certain locales, so you can't accumulate the result. For example:
setlocale(LC_ALL, 'es_ES');
echo(sprintf("%.2f", 13.332) + sprintf("%.2f", 14.446))
gives 27 instead of 27.78, so use %F instead.
In the examples, is being shown printf, but it should say sprintf, which is the function being explained... just a simple edition mistake.
php printf and sprintf not seems to support star "*" formatting.
here is an example:
printf("%*d\n",3,5);
this will print just "d" instead of "<two spaces>5"
In the last example of Example#6, there is an error regarding the output.
printf("[%10.10s]\n", $t); // left-justification but with a cutoff of 10 characters
This outputs right-justified.
In order to output left-justified:
printf("[%-10.10s]\n", $t);
To add to other notes below about floating point problems, I noted that %f and %F will apparently output a maximum precision of 6 as a default so you have to specify 1.15f (eg) if you need more.
In my case, the input (from MySQL) was a string with 15 digits of precision that was displayed with 6. Likely what happens is that the rounding occurs in the conversion to a float before it is displayed. Displaying it as 1.15f (or in my case, %s) shows the correct number.
If the format string is enclosed in double-quotes (""), you need to escape the dollar sign after argnum with a backslash character (\), like this %1\$s, so that the PHP doesn't try to interpret them as variable. Using a backslash like this is called an escape sequence.
<?php
// Sample string
$number = 499;
$format = "The number without decimal points: %1\$d, and the number with two decimal points: %1\$.2f";
// Formatting and print the string
printf($format, $number);
?>
An error in my last example:
$b = sprintf("%30.s", $a);
will only add enough spaces before $a to pad the spaces + strlen($a) to 30 places.
My method of centering fixed text in a 72 character width space is:
$a = "Some string here";
$lwidth = 36; // 72/2
$b = sprintf("%".($lwidth + round(strlen($a)/2)).".s", $a);
There is a minor issue in a code of mb_vsprintf function from viktor at textalk dot com.
In "truncate $arg" section the following line:
$arg = mb_substr($precision,0,$precision,$encoding);
needs to be replaced with:
$arg = mb_substr($arg,0,$precision,$encoding);
When you're using Google translator, you have to 'escape' the 'conversion specifications' by putting <span class="notranslate"></span> around them.
Like this:
<?php
function getGoogleTranslation($sString, $bEscapeParams = true)
{
// "escape" sprintf paramerters
if ($bEscapeParams)
{
$sPatern = '/(?:%%|%(?:[0-9]+\$)?[+-]?(?:[ 0]|\'.)?-?[0-9]*(?:\.[0-9]+)?[bcdeufFosxX])/';
$sEscapeString = '<span class="notranslate">$0</span>';
$sString = preg_replace($sPatern, $sEscapeString, $sString);
}
// Compose data array (English to Dutch)
$aData = array(
'v' => '1.0',
'q' => $sString,
'langpair' => 'en|nl',
);
// Initialize connection
$rService = curl_init();
// Connection settings
curl_setopt($rService, CURLOPT_URL, 'http://ajax.googleapis.com/ajax/services/language/translate');
curl_setopt($rService, CURLOPT_RETURNTRANSFER, true);
curl_setopt($rService, CURLOPT_POSTFIELDS, $aData);
// Execute request
$sResponse = curl_exec($rService);
// Close connection
curl_close($rService);
// Extract text from JSON response
$oResponse = json_decode($sResponse);
if (isset($oResponse->responseData->translatedText))
{
$sTranslation = $oResponse->responseData->translatedText;
}
else
{
// If some error occured, use the original string
$sTranslation = $sString;
}
// Replace "notranslate" tags
if ($bEscapeParams)
{
$sEscapePatern = '/<span class="notranslate">([^<]*)<\/span>/';
$sTranslation = preg_replace($sEscapePatern, '$1', $sTranslation);
}
// Return result
return $sTranslation;
}
?>
Thanks to MelTraX for defining the RegExp!
Fix for sprintfn function for named arguments (http://php.net/manual/en/function.sprintf.php#94608):
Change the first line from:
$arg_nums = array_slice(array_flip(array_keys(array(0 => 0) + $args)), 1);
to:
$arg_nums = array_keys($args);
array_unshift($arg_nums, 0);
$arg_nums = array_flip(array_slice($arg_nums, 1, NULL, true));
I've performed a simple speed test. sprintf against PHP string concatenation operator. Test was performed on PHP 7.3 for 1 million interations.
I run this several times and what I've noted that string concatenation took about 2.9 seconds, sprintf took 4.3 seconds.
I was thinking about what is faster, what is better to do when we're going to format our string (for example, the message to the user or for log purposes) containing some variables values. Is it better to concatenate string with variables using operator (dot ".") or to use sprintf. The answer is: when you do not plan to implement any multilanguage mechanisms and feel good with hardcoding some texts, the "dot" is almost 1.5 times faster!
Here's the code:
echo 'Start' . PHP_EOL;
$vS_text = 'some text';
$vS = '';
$vf = microtime(true);
for ($vI = 0; $vI < 1000000; $vI++) {
$vS = 'Start ' . $vI . ' ' . $vS_text . ' ' . $vf . ' end';
}
$vf = microtime(true) - $vf;
echo 'Concat:' . $vf . PHP_EOL;
$vS = '';
$vf = microtime(true);
for ($vI = 0; $vI < 1000000; $vI++) {
$vS = sprintf('Start %d %s %f end', $vI, $vS_text, $vf);
}
$vf = microtime(true) - $vf;
echo 'Spritf:' . $vf . PHP_EOL;
echo sprintf("%.2f", "123456789012345.82");
// result: 123456789012345.81
echo sprintf("%.2f", "123456789012345.85");
// result: 123456789012345.84
echo sprintf("%.2f", "123456789012345.87");
//result: 123456789012345.88
echo sprintf("%.2f", "123456789012345.820");
//result: 123456789012345.81
echo sprintf("%.2f", "123456789012345.821");
//result: 123456789012345.83
echo sprintf("%.2f", "123456789012345.828");
//result: 123456789012345.83
echo sprintf("%.2f", "123456789012345.8209");
//result : 123456789012345.83
echo sprintf("%.2f", "1234567890123456.82");
//result: 1234567890123456.75
echo sprintf("%.2f", "123456789012345.82002");
//result: 123456789012345.81
echo sprintf("%.2f", "123456789012345.820001");
//result: 123456789012345.81
echo sprintf("%.2f", "123456789012345.820101");
//result: 123456789012345.81
echo sprintf("%.2f", "123456789012345.820201");
//result: 123456789012345.81
echo sprintf("%.2f", "123456789012345.820301");
//result: 123456789012345.81
echo sprintf("%.2f", "123456789012345.820401");
//result: 123456789012345.83