Could some one please Explain why echo 05000 = 2560 ???
i don't get it , i tried to search over the net i didn't find it somewhere
Thank you
05000 is octal notation, 2560 is decimal notation.
The leading 0 means that the number is in octal (base 8) rather than decimal (base 10).
50008 = 5×83 + 0×82 + 0×81 + 0×80 = 256010
It's a string integer literal in octal notation.
You can do base conversions with base_convert. Example:
echo base_convert("5000", 8, 10); //echoes "2560"
See Positional notation.
Related
I need transform 100 to 1.00, 345 to 3.45 or any number with 3 digits or more to record in db like a decimal.
Don't need add .00, just transform last two numbers in decimal.
I try number_format($num, 2) but is wrong.
It seems, that you want to divide your numbers to 100, so using number_format() with the appropriate $decimal_separator and $thousands_separator is an option:
<?php
echo number_format($num / 100, 2, '.', '');
?>
Since you are converting from an integer to a float, you can achieve this simply by dividing the number by 100.
$input = 100;
$value = floatval($input) / 100;
$value = number_format($value, 2);
echo $value;
You may then use number_format (as you were using before) to force two decimal places after any evenly divided float numbers (such as 100).
Demo: PHP Sandbox Example
print_r(bin2hex("11111111"));
echo '</br>';
print_r(bindec("11111111"));
Result
131313131313131
255
I want a hexadecimal 16 byte value to do aes encryption.How is the conversion from binary to hex happening in php.I am getting incorrect value using the function.Also when i convert an array of hexadecimal values to string the byte length changes
You get a correct result, it's just not what you want. bin2hex() returns an ASCII string of the hexadecimal representation. A quote from the manual:
Returns an ASCII string containing the hexadecimal representation of str.
So If you want the hexadecimal number you can use this:
print_r(dechex(bindec("11111111")));
The converter to get hexidecimal is dechex(), but it needs a decimal number. To do that we convert you binary string to a decimal number first using bindec() and then pass it into dechex(), e.g:
print_r(dechex(bindec("11111111")));
<?php
$str = "Hello world!";
echo bin2hex($str) . "<br>";
echo pack("H*",bin2hex($str)) . "<br>";
?>
PHP.NET Manual :
http://php.net/manual/en/function.bin2hex.php
Test Your Result : http://www.cs.princeton.edu/courses/archive/fall07/cos109/bc.html
Detailed Explanation:
http://www.computerhope.com/binhex.htm
It's simply 9 * 16 + F where F is 15 (the letters A thru F stand for 10 thru 15). In other words, 0x9F is 159.
It's no different really to the number 314,159 being:
3 * 100,000 (10^5, "to the power of", not "xor")
+ 1 * 10,000 (10^4)
+ 4 * 1,000 (10^3)
+ 1 * 100 (10^2)
+ 5 * 10 (10^1)
+ 9 * 1 (10^0)
for decimal (base 10).
The signedness of such a number is sort of "one level up" from there. The unsigned value of 159 (in 8 bits) is indeed a negative number but only if you interpret it as one.
I know of the PHP function floor() but that doesn't work how I want it to in negative numbers.
This is how floor works
floor( 1234.567); // 1234
floor(-1234.567); // -1235
This is what I WANT
truncate( 1234.567); // 1234
truncate(-1234.567); // -1234
Is there a PHP function that will return -1234?
I know I could do this but I'm hoping for a single built-in function
$num = -1234.567;
echo $num >= 0 ? floor($num) : ceil($num);
Yes intval
intval(1234.567);
intval(-1234.567);
Truncate floats with specific precision:
echo bcdiv(2.56789, 1, 1); // 2.5
echo bcdiv(2.56789, 1, 3); // 2.567
echo bcdiv(-2.56789, 1, 1); // -2.5
echo bcdiv(-2.56789, 1, 3); // -2.567
This method solve the problem with round() function.
Also you can use typecasting (no need to use functions),
(int) 1234.567; // 1234
(int) -1234.567; // -1234
http://php.net/manual/en/language.types.type-juggling.php
You can see the difference between intval and (int) typecasting from here.
another hack is using prefix ~~ :
echo ~~1234.567; // 1234
echo ~~-1234.567; // 1234
it's simpler and faster
Tilde ~ is bitwise NOT operator in PHP and Javascript
Double tilde(~) is a quick way to cast variable as integer, where it is called 'two tildes' to indicate a form of double negation.
It removes everything after the decimal point because the bitwise operators implicitly convert their operands to signed 32-bit integers. This works whether the operands are (floating-point) numbers or strings, and the result is a number
reference:
https://en.wikipedia.org/wiki/Double_tilde
What does ~~ ("double tilde") do in Javascript?
you can use intval(number); but if your number bigger than 2147483648 (and your machine/os is x64) all bigs will be truncated to 2147483648. So you can use
if($number < 0 )
$res = round($number);
else
$res = floor($number);
echo $res;
You can shift the decimal to the desired place, intval, and shift back:
function truncate($number, $precision = 0) {
// warning: precision is limited by the size of the int type
$shift = pow(10, $precision);
return intval($number * $shift)/$shift;
}
Note the warning about size of int -- this is because $number is potentially being multiplied by a large number ($shift) which could make the resulting number too large to be stored as an integer type. Possibly converting to floating point might be better.
You could get fancy with a $base parameter, and sending that to intval(...).
Could (should) also get fancy with error/bounds checking.
An alternative approach would be to treat number as a string, find the decimal point and do a substring at the appropriate place after the decimal based on the desired precision. Relatively speaking, that won't be fast.
I need to do this rather strange thing, let's say i have:
$number = rand(1, 9);
(This is just an example of what number it could be, in reality i get it in entirely different way)
And now i need "convert" that number to 0.2 or whatever number i got, basically it has to begin with 0 and be a float type of number.
PHP does not support explicit type casting in variable declaration. To convert the int to a float in the way you want to simply divide by 10:
$number = rand(1, 9) / 10;
See this page on PHP Type Juggling for more info. If you mix floats and ints or other types they will be re-casted. Exmple:
echo 10 + 2.5; // gives you 12.5, a float because of the types used
Edit: PHP does have explicit type casting, just not in variable declaration. But even if you cast an integer as a float, it won't display with a decimal place. To do that use PHP's number_format function instead:
echo number_format(10, 1); // gives you 10.0
Edit 2: If you simply want to make your number a decimal between 0 and 1 (such that 2 becomes 0.2, 25 becomes 0.25, etc.) you could use the following function:
function getNumAsDecimal($num) {
return ($num / pow(10, strlen((string)$num)));
}
So getNumAsDecimal(2) would return 0.2.
function Floatize(){
return (float) (rand(1, 9) / 10);
}
echo Floatize(); // will return something like 0.2 or 0.5 or 0.9
$number=(float)rand(1, 9)/10;
See PHP type casting.
$y = 013;
echo $y + 5; //this result in 16
I can not figure it out how its ans is 16? Can any one help?
because 013 isn't decimal (base 10). it's octal (base 8). the value in decimal is:
(0 * 8^2) + (1 * 8^1) + (3 * 8^0) = 0 + 8 + 3 = 11
which gives the correct (though unexpected, at least by you) result of 16 when added to 5.
moral of the story: don't prepend a number literal with 0 unless you know what it means
number with leading zero is octal number
like
$a = 0123; // octal number (equivalent to 83 decimal
Integers can be specified in decimal
(base 10), hexadecimal (base 16), or
octal (base 8) notation, optionally
preceded by a sign (- or +).
To use octal notation, precede the
number with a 0 (zero). To use
hexadecimal notation precede the
number with 0x.
$y = 013;
echo $y + 5;
013 is octal number all php integer numbers are octal .
show this link. first.
http://www.ascii.cl/conversion.htm