I have a multidimentional array of 5 items and I want that my loop would compare it like:
1 -> 2, 1 -> 3, 1 -> 4, 1 -> 5, 2->1, 2->3, 2->4, 2->5......// so on and 5 -> 4 in the end.
The problem is that after my array $i value matches 1 and $j value matches 3, the unset is done and the $i value becomes 2 (which is correct) and $j value becomes 4 instead of 3. Could someone tell me why and what I'm doing wrong?
My loop is:
for ($i = 0; $i <= count($myArray); $i++) {
for ($j = $i+1; $j <= count($myArray); $j++) {
if (
// condition 1
&& // condition 2
) {
unset($myArray[$i]);
$i++;
}
}
}
I think that's the problem is when you unset the element in the array, you increment the counter of the loop $i. In this way, the elements of the array that are not configured are removed, this empty array position will be maintained, it will not be reordered, you will have to do it manually or using array_values method.
In the last tour of the array, it will break because you are comparing the number of array elements as equal. You must use index < count($array)
The code would be like this:
for ($i = 0; $i < count($myArray); $i++) {
for ($j = $i+1; $j < count($myArray); $j++) {
if (
// condition 1
&& // condition 2
) {
unset($myArray[$i]);
// $i++;
}
}
}
try something like this
for ($i = 0; $i <= count($myArray); $i++) {
for ($j = 0; $j <= count($myArray); $j++) {
if ($j!=$i)
{
if (
// condition 1
&& // condition 2
) {
unset($myArray[$i]);
$i++;
}
}
}
}
$temp = $myArray;
for ($i = 0; $i <= count($myArray); $i++)
{
for ($j = $i + 1; $j <= count($myArray); $j++)
{
if (
// condition 1
&& // condition 2
)
{
unset($temp[$i]);
$i++;
}
}
}
print_r($temp);
Your result is in $temp. So here indexes wont get hampered, you actually are applying all operation on $temp and normally traversing $myArray.
To be honest, I do not know why nobody has yet advise to use nested foreach, since you all noticed there was a problem with array size.
foreach ($numbers as $number_horizontal_parsing) {
foreach ($numbers as $number_vertical_parsing) {
if ($number_horizontal_parsing != $number_vertical_parsing) {
//do your stuff in your case it seems you want to compare both variables
}
}
}
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
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/>";
}
?>