So I want to get number with Consecutive Numbers like below.
1234567891011121314151617181920212223..............
when i input 10 then output is 1. and so on like below.
10th digit is 1
11th digit is 0
12th digit is 1
13th digit is 1
14th digit is 1
15th digit is 2
16th digit is 1
17th digit is 3
This is my code to make Consecutive Numbers. Its work as i want expected.
<?php
$i=1;
$urut='';
$a = $_GET['button1'];
echo "Your number ", $a, "<br>";
while ($i<=$a){
$urut=$urut.''.$i;
$i++;
}
$pecah = str_split($urut,1);
echo "Urut angka ke ".$a."adalah ". $pecah[$a-1];
?>
But my case is how to get number when Consecutive up to 1 million or more.
I tried that but when set 1 millions or more its load very long time and cant show the result number
You'll probably need to do something like calculating the length of each range of numbers.
For example you know that:
1 through 9 are 1 character
10 through 99 are 2 characters
100 through 999 are 3 characters
And so on
Doing so will allow you to calculate the length of the string up to a certain number.
For example the amount of characters before 1000 can be calculated like so.
9x1 + (99 - 10) x 2 + (999 - 100) x 3
Using this you can distil a formula which allows you to calculate the value for any given number.
Let’s say I have a series of numbers like:
12345678910111213141516... (until unlimited)
Then I would like to get a number from it by given digit. For example:
Digit 10th: 1
Digit 17th: 3
...
I have tried to make the algorithm to do it by using PHP but it always showed me an error due to the looping that I made was out of memory size if the given digit that I gave is more than 10.000.000. Allowed Memory Size of 134217728 Bytes Exhausted
How do I deal with this without having to modify memory_limit on php.ini file?
Here are what I have tried to figure the algorithm out: I benchmark the maximum of upper limit of the loop that my local machine could handle, and I found out it's 10.000.000, then I assumed I need to make a separate loop if the given digit/parameter is more than 10.000.000. But in the end I still got that error of out of memory size. Really grateful in advance.
<?php
/*
* benchmark result:
* max digit = 10.000.000
*/
$benchmarkedDigit = 10000000;
$digit = 1000000000000; // it could be dynamically assigned, i.e. a parameter. In this case will show an error since the given digit is 10 trillion
$s = '';
if ($digit > $benchmarkedDigit) {
$mod = fmod($digit, $benchmarkedDigit);
$div = $digit / $benchmarkedDigit;
for ($x = 1; $x <= $div; $x++) {
$upperLimit = ($x * $benchmarkedDigit);
for ($y = ($upperLimit - $benchmarkedDigit + 1); $y <= $upperLimit; $y++) {
$s .= $y;
}
// so it could be:
// 1 - 10.000.000
// 10.000.001 - 20.000.000
// 20.000.001 - 30.000.000
// ...
}
// loop for the rest of the fmod(), if its result is not 0
for ($i = ($upperLimit + 1); $i <= ($upperLimit + $mod); $i++) {
$s .= $i;
}
} else {
for ($x = 1; $x <= $digit; $x++) {
$s .= $x;
}
}
echo substr($s, ($digit - 1), 1);
You can use the fact that there's always 10^n - 10^(n-1) number of n-digit long numbers (even 1 digit, because I see 0 is not there).
With this knowledge, you can skip potentially huge number of numbers.
You start with n=1, and check if the number of n digit numbers is lower than the desired digit. If it is, then reduce the number of n digit numbers from the desired number, increase n by one and start again.
For example: you want to know the 512th digit in that number
Is the number of 1 digit numbers (10) lower than the desired digit (512)?
Yes, so the desired digit should be reduced by that many (512 - 9).
Is the number of 2 digit numbers (90) lower than the desired digit (503 now)?
Yes, so the desired digit should be reduced by that many (503 - 90).
Is the number of 3 digit numbers (900) lower than the desired digit(413 now)?
No, so the desired digit is one of the digits of a 3 digit number.
413 / 3 is 137 (rounded down), so it's one of the digits of the 137th 3 digit numbers (so 237).
413 % 3 (modulo) is 2, so it's the 2nd digit, so it's supposed to be 3.
There can be miscalculations in this, but the overall logic should not be far.
Edit: you could also use a generator, but this can increase the runtime for big numbers
function getNthDigit() {
for ($i = 0;; ++$i) { // Start with 0, which is the 0-th digit
foreach (str_split((string)$i) as $digit) {
yield $digit;
}
}
}
$desiredDigit = 512;
foreach (getNthDigit() as $number => $digit) {
if ($number == $desiredDigit) {
break;
}
}
// $digit should be the desired digit
<?php
function getDigit($Nth){
if($Nth < 10) return $Nth;
$no_of_digits = 1;
$current_contribution = 9;
$actual_length = 9;
$prev_length = 0;
$starting_number = 1;
$power_of_10 = 1;
while($actual_length < $Nth){
$no_of_digits++;
$current_contribution *= 10;
$prev_length = $actual_length;
$actual_length += ($current_contribution * $no_of_digits);
$power_of_10 *= 10;
$starting_number *= 10;
}
$Nth = $Nth - $prev_length;
$offset = $Nth % $no_of_digits === 0 ? intval($Nth / $no_of_digits) - 1 : intval($Nth / $no_of_digits);
$number = strval($starting_number + $offset);
for($i=1;$i<=$no_of_digits;++$i){
if(($Nth - $i) % $no_of_digits === 0){
return $number[$i-1];
}
}
}
// first 100 Digits
for($i=1;$i<=100;++$i){
echo getDigit($i),PHP_EOL;
}
Demo: https://3v4l.org/3l0I7
Algorithm:
To find the nth digit, we will first find the number and then which digit of that number to choose as an answer.
Find the number:
If we carefully observe, the series increases in a sequential manner, such as shown in the table.
Table:
| Digits| Total numbers(of current digit)| Total Digits | Total digits of whole string |
|-------|--------------------------------|--------------|-------------------------------|
| 1 | 9 | 9 | 9 |
| 2 | 90 | 180 | 189 |
| 3 | 900 | 2700 | 2889 |
| 4 | 9000 | 36000 | 38889 |
The above table shows us that if we want to find, let's say 500th digit, then it's some digit of 3 digit number. If we go for 17th digit, then it's some digit of a 2 digit number and so on.
Now, let's take 200th digit as an example. Since it's less than 2889 and greater than 189, it's from a 3 digit number.
What we would do is breakdown the 200 into a smaller number such as 200 - 189 = 11. This 11 means that it's 11th digit of some 3 digit number which started with initial 3 digit number of 100(the starting number for 3 digit).
Now, we do 11 / 3(where 3 is number of digits) and get the quotient as 3. This 3 means that it's 3 numbers past the starting number 100, which we can say as 100 + 3 = 103(since it's 100,101,102 and then the 4th one as 103).
Now, we came to know that the number is 103. All is left to find out is which digit from 103.
Note that sometimes we come across a corner case of even divisibility such as 12 / 3. In this case, we subtract 1 from the quotient since our series of 3 digits starts from 100 and not 101( and so on and so forth for other digits).
Find out the digit:
Now, we know that the number is 103 for a 200 th digit( a.k.a 11 as we calculated above). To find out which one, we write down numbers of 3 digits in sequence and closely observe them.
Sequence:
1 0 0 1 0 1 1 0 2 1 0 3 1 0 4 1 0 5 1 0 6
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21
If you observe, you can understand that the most MSB digit follows a sequence of 1,4,7,10,13 etc. Second most MSB follows a sequence of 2,5,8,11,14 etc and the last MSB(which is LSB) follows a sequence of 3,6,9,12,15 etc.
So, from th above sequence, it's pretty evident that 11(which we got after breaking down 200 initially) belongs to a sequence of the 2nd most MSB digit.
So, the final answer from 103 is 0 (the 2nd digit from left).
$num = '12345678910111213141516';
echo $num[16];
Result: 3
How would one get the integer value of the n-th value from n?
This is hard to phrase so I'll just use English. If I wanted the 3rd integer value from 1...
1 = 1
2 = 3
3 = 4 <- (looking to get 4 using 3)
4 = 8
5 = 16 <- (or 16 using 5)
...
I could just do a lookup table, but I'm sure there's a better solution.
$bitvalue = 5;
$intvalue = 2 ** ($bitvalue - 1);
// gives 16
echo $intvalue;
The ** operator is the power operator. So I'm using powers of 2.
I having difficulties to get the next specific value from an array.
while (list($index, $day) = each($user['days'])) {
}
in $user['days] I have all of the date from a specific month in the key and in the value i have to type of values: 480 or 4 K .
for instance:
$user[1] = 480
$user[2] = 480
$user[3] = 4 K
......
$user[25] = 4 K
$user[26] = 480
.....
$user[30] = 4 K
so If I have two 4 K , the first will become 480 and next will become 8 F
if I have 4 of 4 K I will have two 480 and two 8 F
and if in the final it remains a 4 K I have to change on the next month to become 8 F and in the current month should remain 480. Can someone help me with this ?
I almost did not understand, but maybe this function help you
array_keys ( $user, '4 K');
it will return array (3,25,30). It's length gives you a count of '4 K', and values will be the keys of user array
I've got a grid of 10 square list items. A bit like a gallery. If the user adds another item there will be 11. However this will look strange as the 11th item will be on its own in a new row. How can I use PHP to round up to the nearest 5 and add in the some blank/dummy list items?
You could use the modulo operator to identify the remainder of a division:
10 % 5 = 0
11 % 5 = 1
12 % 5 = 2
13 % 5 = 3
14 % 5 = 4
15 % 5 = 0
With that you can identify if (and how large) such an uncomplete row would be. Knowing how many elements are in that last uncomplete row oviously allows you to calculate the number of remaining cells to fill the row.
($y+(($y%$x)?($x-($y%$x)):0))
...where $y is the number of items(e.g. 11) and $x is the number of items in a row(e.g. 5)