First of all, thanks for looking at my question.
I only want to add up the positive numbers in the $numbers using a if,else statement.
$numbers = array (1, 8, 12, 7, 14, -13, 8, 1, -1, 14, 7);
$total = 0;
if ($numbers < 0 {
$numbers = 0;
}
elseif (now i want only the positive numbers to add up in the $total.)
I'm an first years student and I am trying to understand the logic.
I'm not gonna give the direct answer, but the way here is you need a simple loop, can be for or a foreach loop, so every iteration you just need to check whether the current number in the loop is grater than zero.
Example:
$numbers = array (1, 8, 12, 7, 14, -13, 8, 1, -1, 14, 7);
$total = 0;
foreach($numbers as $number) { // each loop, this `$number` will hold each number inside that array
if($number > 0) { // if its greater than zero, then make the arithmetic here inside the if block
// add them up here
// $total
} else {
// so if the number is less than zero, it will go to this block
}
}
Or as michael said in the comments, a function also can be used in this purpose:
$numbers = array (1, 8, 12, 7, 14, -13, 8, 1, -1, 14, 7);
$total = array_sum(array_filter($numbers, function ($num){
return $num > 0;
}));
echo $total;
$numbers = array (1, 8, 12, 7, 14, -13, 8, 1, -1, 14, 7);
$total = 0;
foreach($numbers as $number)
{
if($number > 0)
$total += $number;
}
this loops through all elements of the array(foreach = for each number in the array) and checks if the element is bigger than 0, if it is, add it to the $total
Related
I need a simpler way like 1 - 100 instead of adding any number and number (1,2,3....)
$all_urls = array(1,2,3,4..,100);
foreach ($all_urls as $url){
$xml = simplexml_load_file("http://localhost/$url");
}
You can use range():
Create an array containing a range of elements
// array(0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
foreach (range(0, 12) as $number) {
echo $number;
}
$all_urls = range(1,100);
I have the following randomly generated string:
$text = 's$bp4q1hsq3#g88nsjm5hr#i9#3078e2m';
What I need is to take all integers from it and classify them as either prime or composite numbers and estimate their sum. All numbers should be assumed that are one digit so this shortens the values to only four per each group:
$primes = array(2, 3, 5, 7);
$composites = array(4, 6, 8, 9);
This means: Primes: 5, 3, 3, 2 = 13 and Composites: 4, 8, 8, 9, 8 = 37 as duplicate numbers also count.
I have tried grabbing the numbers like so:
$asArray = str_split($text);
foreach ($asArray as $element) {
if (is_int($element)) {
echo $element;
}
}
But it seems to end up in a blank page. So my question is how can I find out the numbers in a string and then classify them as either prime or composite?
Here you have the sum of the primes and composites:
$text = 's$bp4q1hsq3#g88nsjm5hr#i9#3078e2m';
$primes = array(2, 3, 5, 7);
$sum_primes = $sum_composites = 0;
preg_match_all("/\d/", $text, $matches);
foreach($matches[0] as $number)
{
if (in_array($number, $primes))
$sum_primes += $number;
else
$sum_composites += $number;
}
echo "Sum of primes: ".$sum_primes."\n";
echo "Sum of composites: ".$sum_composites."\n";
It would print,
Sum of primes: 20
Sum of composites: 38
Problem:
I have a field in my MySQL table with the following value:
9, 10, 11, 12, 13, 14, 15, 16, 26, 27, 28, 29, 30, 31, 32
I use PHP to put the value of this field in the variable: $row['Exclude'];
The problem is that I am using a function called rand_except() that looks as following:
function rand_except($min, $max, $except)
{
//first sort array values
sort($except, SORT_NUMERIC);
//calculate average gap between except-values
$except_count = count($except);
$avg_gap = ($max - $min + 1 - $except_count) / ($except_count + 1);
if ($avg_gap <= 0)
return false;
//now add min and max to $except, so all gaps between $except-values can be calculated
array_unshift($except, $min - 1);
array_push($except, $max + 1);
$except_count += 2;
//iterate through all values of except. If gap between 2 values is higher than average gap,
// create random in this gap
for ($i = 1; $i < $except_count; $i++)
if ($except[$i] - $except[$i - 1] - 1 >= $avg_gap)
return mt_rand($except[$i - 1] + 1, $except[$i] - 1);
return false;
}
In order for this to work it needs to be like this:
$exclude = array(9, 10, 11, 12, 13, 14, 15, 16, 26, 27, 28, 29, 30, 31, 32);
$_SESSION['experimentversion'] = rand_except(1, 32, $exclude);
Question:
How can I take the database field $row['Exclude'] and transform it into an array so it will work with the function?
Simple. Use Explode function.
$s = "1,2,3,4";
$y = explode(",", $s);
print_r($y)
There is a explode method in php you can use this method
$string = '1,2,3,4,5';
$array = explode(",",$string);
print_r($array);
it will create an array.
$exclude = explode(', ', $row['Exclude']);
$str = '1,2,3,4,5';
$arr = explode(",",$str);
print_r($arr);
This should do the trick:
$exclude = explode(", ", $row['Exclude']);
use explode function.. for more info of Explode Visi this link
$row = "retrive your value from db";
$data = explode(", ",$row);
print_r($data); //here you will get array of your db field
I want generate a range of numbers orderly. I mean opposite of rand function in php. I test with range but it generate only array of numbers
For example
min 1 and max 3
rand(1,3);// 2,1,3
but i want 1,2,3
Any in built in functions in php like rand for getting this features without using any loops?
Use range() to generate numbers
// array(0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
foreach (range(0, 12) as $number) {
echo $number;
}
You can achieve this using for loop
for ($i = 1; $i <= 3; $i++) {
echo $i;
}
// array(0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
foreach (range(0, 12) as $number) {
echo $number;
}
If you are using php then take a look at range function
If I understand your slightly missleading question.. this might do it:
$string = implode(', ', range(1,3));
echo $string;
And not a loop in sight :)
Or as a one liner:
echo implode(', ', range(1,3));
I need to randomly generate an two-dimensional n by n array. In this example, n = 10. The array should have this structure. One example:
$igra[]=array(0,1,2,3,4,5,6,7,8,9);
$igra[]=array(6,9,1,5,0,2,7,3,4,8);
$igra[]=array(2,5....................
$igra[]=array(1,7.....................
$igra[]=array(5,4...................
$igra[]=array(4,2...................
$igra[]=array(9,0.....................
$igra[]=array(8,3.....................
$igra[]=array(7,6....................
$igra[]=array(3,8....................
where
`$igra[x][z]!=$igra[y][z]` (x={0,9},y={0,9});
as you see it's like a matrix of numbers each row of it and column also consist from numbers 0-9, and there is never one number two times in each row or in each column.
how to generate such an array, and each time randomly.
Okay, so here's my version:
$n = 10;
$v1 = range(0, $n-1);
$v2 = range(0, $n-1);
shuffle($v1);
shuffle($v2);
foreach ($v1 as $x => $value)
foreach ($v2 as $y)
$array[$y][$x] = $value++ % $n;
This should be a really fast algorithm, because it involves only generating two random arrays and doesn't involve any swapping at all. It should be random, too, but I cannot prove it. (At least I don't know how to prove something like this.)
This is an optimized version of a very simple algorithm:
First a non-random matrix is created this way (imagine we want only 5*5, not 10*10):
0 1 2 3 4
1 2 3 4 0
2 3 4 0 1
3 4 0 1 2
4 0 1 2 3
In this matrix we now randomly swap columns. As we don't change the columns themselves your rules still are obeyed. Then we randomly swap rows.
Now, as you can see the above algorithm doesn't swap anything and it doesn't generate the above matrix either. That's because it generates the cols and rows to swap in advance ($v1 and $v2) and then directly writes to the correct position in the resulting array.
Edit: Just did some benchmarking: For $n = 500 it takes 0.3 seconds.
Edit2: After replacing the for loops with foreach loops it only takes 0.2 seconds.
This is what I did. Made a valid matrix (2d array) that isn't random. So starting out, row 0 is 0-9, row 1 is 1-0 (ie: 1,2,3...8,9,0), row 2 is 2-1 (2,3...9,0,1)...row 8 is 8-7...etc. Then shuffle that array to randomize the rows and perform a simple column swap to randomize the columns. Should get back exactly what you want. Try this:
<?php
//simple function to show the matrix in a table.
function show($matrix){
echo '<table border=1 cellspacing=0 cellpadding=5 style="float: left; margin-right:20px;">';
foreach($matrix as $m){
echo '<tr>';
foreach($m as $n){
echo '<td>'.$n.'</td>';
}
echo '</tr>';
}
echo '</table>';
}
//empty array to store the matrix
$matrix = array();
//this is what keeps the current number to put into matrix
$cnt = 0;
//create the simple matrix
for($i=0;$i<=9;$i++){
for($j=0;$j<=9;$j++){
$matrix[$i][$j] = $cnt % 10;
$cnt++;
}
$cnt++;
}
//display valid simple matrix
show($matrix);
//shuffle the rows in matrix to make it random
shuffle($matrix);
//display matrix with shuffled rows.
show($matrix);
//swap the columns in matrix to make it more random.
for($i=0;$i<=9;$i++){
//pick a random column
$r = mt_rand(0, 9);
//now loop through each row and swap the columns $i with $r
for($j=0;$j<=9;$j++){
//store the old column value in another var
$old = $matrix[$j][$i];
//swap the column on this row with the random one
$matrix[$j][$i] = $matrix[$j][$r];
$matrix[$j][$r] = $old;
}
}
//display final matrix with random rows and cols
show($matrix);
?>
In my solution, by not generating a random array and checking if it already exists, it should run much faster (especially if the array ever went above 0-9). When you get down to the last row, there is only one possible combination of numbers. You will be generating random arrays trying to find that one answer. It would be pretty much the same as picking a number from 1 to 10 and generating a random number until it hits the one you picked. It could be on the first try, but then again you could pick 1000 random numbers and never get the one you wanted.
Hmm.. I see you got some good answers already, but here's my version:
$n = 10;
$seed_row = range(0, $n - 1);
shuffle($seed_row);
$result = array();
for($x = 0; $x < $n; $x++)
{
$tmp_ar = array();
$rnd_start = $seed_row[$x];
for($y = $rnd_start; $y < ($n + $rnd_start); $y++)
{
if($y >= $n) $idx = $y - $n;
else $idx = $y;
$tmp_ar[] = $seed_row[$idx];
}
$result[] = $tmp_ar;
}
for($x = 0; $x < $n; $x++)
{
echo implode(', ', $result[$x]) . "<br/>\n";
}
sample output:
4, 3, 0, 2, 6, 5, 7, 1, 8, 9
0, 2, 6, 5, 7, 1, 8, 9, 4, 3
7, 1, 8, 9, 4, 3, 0, 2, 6, 5
2, 6, 5, 7, 1, 8, 9, 4, 3, 0
6, 5, 7, 1, 8, 9, 4, 3, 0, 2
9, 4, 3, 0, 2, 6, 5, 7, 1, 8
8, 9, 4, 3, 0, 2, 6, 5, 7, 1
5, 7, 1, 8, 9, 4, 3, 0, 2, 6
1, 8, 9, 4, 3, 0, 2, 6, 5, 7
3, 0, 2, 6, 5, 7, 1, 8, 9, 4
It creates a random random array as a starting point
Then it walks through the seed array taking each element as a starting point for itself to create a new base.