PHP Generate possible number with specific format - php

I need to generate possible number with some format/rule.
5 digit number
first digit > 0
for($x=0;$x=10;$x++) {
$first=1;$second=0;$third=0;$fourth=0;$five=0;
for($i=1;$i<10;$i++){
$first=$i; break;
}
for($i=0;$i<10;$i++){
$second=$i; break;
}
for($i=0;$i<10;$i++){
$third=$i; break;
}
for($i=0;$i<10;$i++){
$fourth=$i; break;
}
for($i=0;$i<10;$i++){
$five=$i; break;
}
echo $first.$second.$third.$fourth.$five.'\n';
}
desired result:
10000
10001
10002
...until
99999
but seems broken :(


Instead of using separate for loops you need to nest them inside one another:
for($i = 1; $i <= 9; $i++){
for($j = 0; $j <= 9; $j++){
for($k = 0; $k <= 9; $k++){
for($l = 0; $l <= 9; $l++){
for($m = 0; $m <= 9; $m++){
print("$i$j$k$l$m\n");
}
}
}
}
}
DEMO
But, obviously, a simpler approach would employ only one for loop:
for($i = 10000; $i <= 99999; $i++){
print("$i\n");
}
DEMO

Related

For loop (php) that results in this: 12345678910987654321

My niece is trying to create one for-loop (php), that results in this:
* 12345678910987654321
example for loop she tried:
for ($i = 1; $i <= 10; $i++ , $i = 10; $i <= 1; $i--) {
echo $i . ' ';
}
She can only use if's and elseif's. I'm not a programmer and can't really help her. Any ideas how this could be achieved in php?
Any information would be greatly appreciated.

The key is to add a variable instead of a number, then reverse that number when $i hits 10.
for($i = 1, $j = 1; $i> 0; $i+=$j) // Start i at 1, and j at 1
{
echo $i;
if($i == 10)
$j = -1; // i has hit 10, so use -1 to start subtracting
}

Another possibility is to loop up to 20, printing $i for the ascending part and 20 - $i for the descending.
for ($i = 1; $i < 20; $i++) {
if ($i <= 10) {
echo $i;
} else {
echo 20 - $i;
}
}

add in loop in multi dimensional array

i am facing a problem
can some one suggest me
for ($i = 1; $i <= 2; $i++) {
$r2 = 0;
for ($t = 1; $t <= 2; $t++) {
echo $r2;
$r2++
}
}
output is 0101;
can i get output 0123 ??? please
if
for ($i = 1; $i <= 3; $i++) {
$r2 = 0;
for ($t = 1; $t <= 3; $t++) {
echo $r2;
$r2++
}
}
output is 010101;
can output 012345678 ??? please
and if
for ($i = 1; $i <= 4; $i++) {
$r2 = 0;
for ($t = 1; $t <= 4; $t++) {
echo $r2;
$r2++
}
}
output is 01010101;
can output 0123456789101112131415 ??? please
i think you understand
thanks

In all of these cases you are initializing $r2=0; in the inner loop. It should be outside the loop.
$r2=0;
for($i=1;$i<=2;$i++){
for($t=1;$t<=2;$t++){
echo $r2;
$r2++
}
}
This would produce "1234".

why are you using two nested for loops ?
why not just use one:
for ($i=0; $i<=15; $i++) echo $i . " ";

Try this:
$r2 = 10;
for($t = 0; $t <= $r2; $t++){
echo $r2;
}

Oh wait.. I get it now, why you have the two nested loops, you want to essentially raise a number to the power of 2 in order to control the number of values output. In that case, what you want is simply this:
// this is the variable you need to change to affect the number of values outputed
$n = 2;
// Square $n
$m = $n * $n;
// Loop $m times
for ($i = 0; $i < $m; $i++) {
echo $i;
}

decrese value of loop

I have this code, but i want in second loop a decrease of $p value. The first internal loop must be repeated three times, the second, two times and the last, one time. I am trying $p-- but without success.
Any idea ? thanks
$p = 3;
for ($i = 0; $i < 3; $i++) {
for ($o = 0; $o < $p; $o++) {
echo "something";
$p--;
}
}

Move your $p-- to outside the inner for loop:
$p = 3;
for ($i = 0; $i < 3; $i++) {
for ($o = 0; $o < $p; $o++) {
echo "something";
}
$p--;
}
Or better, just depend on the value of $i:
for ($i = 0; $i < 3; $i++) {
for ($o = 0; $o < 3 - $i; $o++) {
echo "something";
}
}
Or if you don't actually use $i:
for ($i = 2; $i >= 0; $i--) {
for ($o = 0; $o < $i; $o++) {
echo "something";
}
}

It's quite simple.
for ($i = 2; $i >= 0; $i--)
{
}
Set the starting number at the upper limit number, and then go down until equal to 0, $i minus 1;

You need to decrement $p outside the first loop

create var's with others

I want to create somthing like 100 var's which their names will be:
$numbr_1 = 1;
$numbe_2 = 2;
$number_3 = 3;
...
I won't write 100 vars of course, but there is a way to do it with foor loop or somthing? I thought about this:
for ($i = 1; $i <= 100; $i++)
$number_{$i} = $i;

You're talking about variable variables, and they are incredibly stupid to use. For one, they make debugging next to impossible.
What you want is an array:
for ($i = 1; $i <= 100; $i++) {
$numbers[$i] = $i;
}

Something like this should work:
for($i = 1 ; $i <= 100 ; $i++){
$var_name = "number_$i";
$$var_name = $i;
}

for($i=1;$i<=100;$i++) {
$j="number$i";
$$j = $i;
}

Why don't you use an array?
$number = array();
for ($i = 0; $i < 100; $i++)
{
$number[] = $i;
}

for($i = 1 ; $i <= 100 ; $i++){
${'number_'.$i} = $i;
}

Possible solution is usage of array.
$number = array();
for ($i = 1; $i <= 100; $i++) {
$number[$i] = $i;
}

php array output problem

In php is there a function to increment the
values of subsequent values twice(*2) in an array
column based on an initial value?
$beta = array(
array('5', '1''1','1','1','1','1','1','1','1','1','1','1','1','1','1','1','1','1','1'),
array('5','2','2','2','2','2','2','2','2','2','2','2','2','2','2','2','2','2','2','2'),
array('5','2','2','2','2','2','2','2','2','2','2','2','2','2','2','2','2','2','2','2'),
array('5','2','2','2','2','2','2','2','2','2','2','2','2','2','2','2','2','2','2','2'),
array('5','2','2','2','2','2','2','2','2','2','2','2','2','2','2','2','2','2','2','2'),
array('5','2','2','2','2','2','2','2','2','2','2','2','2','2','2','2','2','2','2','2'),
array('5','2','2','2','2','2','2','2','2','2','2','2','2','2','2','2','2','2','2','2'),
array('5','2','2','2','2','2','2','2','2','2','2','2','2','2','2','2','2','2','2','2'),
array('5','2','2','2','2','2','2','2','2','2','2','2','2','2','2','2','2','2','2','2'),
array('5','2','2','2','2','2','2','2','2','2','2','2','2','2','2','2','2','2','2','2')
);
/*Example: '5' will be '10' (5*2 =10 and output 10 to web)
'2' will be '4' (2*2 = 4 and output 4 to web)
The next '2' will be '16' (4*2 = 8 and output 8 to web)
The next '2' will be '32' (8*2 = 16 and output 16 to web)
And so forth? */
Furthermore is there an easier way to construct this array, cause I firmly believe there is, but not something too complicated in terms of construct such that a noob will not understand it, again thanks.
[Disclaimer: I have spent 3 days trying to understand arrays, I now understand them; however, I am still new and am currently having some issues when trying to manipulate the values in my array and output them to the web.And I am still pretty sure I have a lot to read and learn, so please no flamers, I just need some help, found this problem in this C++ book:
[http://books.google.com/books?id=4Fn_P7tdOZgC&pg=PT424&lpg=PT424&dq=subsequent+++column+is+twice+the+value&source=bl&ots=gSvQ_LhxoI&sig=dG_Ilf1iLO86lqX936cT1PpkPc8&hl=en&ei=OEEBS_eODYyotgOFtJD3CQ&sa=X&oi=book_result&ct=result&resnum=1&ved=0CAgQ6AEwAA#v=onepage&q=subsequent%20%20%20column%20is%20twice%20the%20value&f=false][1]

You can try array_map:
<?php
function increase($n) {
return is_array($n) ? array_map('increase', $n) : $n * 2;
}
$new_beta = array_map("increase", $beta);
As for constructing the array, there are other methods to do so but I believe this is the most performent and clean.

Here is an answer for each question in that section of the book, enjoy!
<?php
// Declare an array alpha of 10 rows and 20 columns of type int
// Initialise the array alpha to 0
$alpha = array(array());
for($i = 0; $i < 10; $i++)
{
for($j = 0; $j < 20; $j++)
{
$alpha[$i][$j] = 0;
}
}
// Store 1 in the first row and 2 in the remaining rows
for($i = 0; $i < 10; $i++)
{
for($j = 0; $j < 20; $j++)
{
if($i == 0)
{
$alpha[$i][$j] = 1;
}
else
{
$alpha[$i][$j] = 2;
}
}
}
// Store 5 in the first column, and make sure that the value in
// each subsequent column is twice the value in the previous column
// (Beware this doesn't build off the initial value of 5 in the first
// column but the previously set values above)
for($i = 0; $i < 10; $i++)
{
for($j = 0; $j < 20; $j++)
{
if($j == 0)
{
$alpha[$i][$j] = 5;
}
else
{
if($j - 1 >= 1)
{
$alpha[$i][$j] = $alpha[$i][$j-1] * 2;
}
}
}
}
// Print the array alpha one row per line
print "Printing the array alpha one row per line:<br/>";
for($i = 0; $i < 10; $i++)
{
for($j = 0; $j < 20; $j++)
{
print "[". $alpha[$i][$j] ."] ";
}
print "<br/>";
}
print "<br/>";
// Print the array alpha one column per line
print "Printing the array alpha one column per line:<br/>";
for($j = 0; $j < 20; $j++)
{
for($i = 0; $i < 10; $i++)
{
print "[". $alpha[$i][$j] ."] ";
}
print "<br/>";
}
?>

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