i want to count number of even,number of odd in php - php

I want to count number of even,number of odd.If there 2 even ,i count only one even,If there 2 odd i count
only one number of odd
<?php
$myarray = array(5,5,0,1,2,1,1,6,1);
for ($i = 0; $i < count($myarray); $i++) {
echo "Index ", $i, ", value ", $myarray[$i], ": ";
if ($myarray[$i] % 2 == 0) {
echo "even\n";
}
else {
echo "odd\n";
}
}
?>
input =[5,5,0,1,2,1,1,6,1]
output = 5 :1(total(5) odd one),
1:2 (total(1) odd two)

Use two variables that keep track of your odds and evens when you loop through your array.
$my_array = array( 5, 5, 0, 1, 2, 1, 1, 6, 1 );
$odd = $even = 0;
foreach ( $my_array as $number ) {
$number % 2 == 0 ? $even++ : $odd++;
}
printf( 'Odd: %s | Even: %s', $odd, $even );

<?php
$num = array(23,12,11,9,6,7,4,5,3);
$n=count($num);
$even = 0;
$odd = 0;
for( $i = 0 ; $i < $n; $i++)
{
if ($num[$i] & 1 == 1)
$odd ++ ;
else
$even ++ ;
}
echo "Number of even elements = $even
and Number of odd elements = $odd" ;
?>

Create counters $evens and odds. Then Loop through elements in array check if number is odd
using Ternary Operator (condition) ? true : false;, and $num & 1 return true if number is odd.
$nums = array(5,5,0,1,2,1,1,6,1);
$odds = $evens = 0;
foreach ($nums as $num) {
$num & 1 ? ++$odds : ++$evens;
}
echo "Odds: $odds, Evens: $evens"; //Odds: 6, Evens: 3

Just count only number of odds, Because If we count number of Odds in array, It would be easy to know number of Evens by subtract number of elements in array with number of Odds
$nums = array(5,5,0,1,2,1,1,6,1);
$odds = 0;
foreach ($nums as $num) {
$odds += $num % 2;
}
$evens = count($nums)-$odds;
echo "Odds: $odds, Evens: $evens"; //Odds: 6, Evens: 3

Related

Print all combination of sub range within a given array

I want to print all combination of sub range in an given array. I have an array of y number of elements in it from which I want to print all combination of contiguous sub range.
Constraint is : each sub range should have at least 2 elements and each element in sub range should be contiguous. It should share same border of each element.
For example, We have an array of 7 elements [11,12,13,14,11,12,13]
So, the total number of sub range combination will [7 * (7-1) /2] = 21
So, the Output will be something like this:
11,12
12,13
13,14
14,11
11,12
12,13
11,12,13
12,13,14
13,14,11
...
11,12,13,14 and so on (total 21 combination as per above array)
we should not print any combination which is not contiguous. example: [11,12,14] is not valid combination as it skips the element "13" in between.
I am able to print the combination with 2 elements but i am having difficulty in printing more then 2 elements combination.
Below is what I have tried so far.
$data=array("11","12","13","14","11","12","13");
$totalCount=count($data);
for($i=0;$i<$totalCount;$i++){
if(($i+1) < ($totalCount)){
echo "[".$data[$i].",".$data[$i+1]."]<br>";
}
}
You can do that:
$arr = [11,12,13,14,11,12,13];
function genComb($arr, $from = 1, $to = -1) {
$arraySize = count($arr);
if ($to == -1) $to = $arraySize;
$sizeLimit = $to + 1;
for ($i = $from; $i < $sizeLimit; $i++) { // size loop
$indexLimit = $arraySize - $i + 1;
for ($j = 0; $j < $indexLimit; $j++) { // position loop
yield array_slice($arr, $j, $i);
}
}
}
$count = 0;
foreach (genComb($arr, 2) as $item) {
echo implode(',', $item), PHP_EOL;
$count++;
}
echo "total: $count\n";
Casimir et Hippolyte was faster, but you can gain huge performance by processing each contiguous section independently:
function getCombos(&$data) {
$combos = array();
$count = count($data);
$i = 0;
while ($i < $count) {
$start = $i++;
while ($i < $count && $data[$i - 1] + 1 == $data[$i]) // look for contiguous items
$i++;
if ($i - $start > 1) // only add if there are at least 2
addCombos($data, $start, $i, $combos); // see other answer
}
return $combos;
}

Create line breaks in output based on array index

I want to display output like this:
1 2 3 4
5 6 7 8
9 1 2
I've tried this code:
$num = ['1','2','3','4','....'];
$size = sizeof($num) / 4;
foreach ($num as $key => $value) {
echo $value;
if($key >= round($size){
echo "<br>"
}
}
But the output is like this:
1 2 3 4
5
6
7
8
...
Can anyone suggest how to write the loop?
$num= ['1','2','3','4','5','6','7','8','9'];
$size = sizeof($num) / 4;
foreach ($num as $key => $value){
echo $value;
if(($key+1) % 4 == 0){
echo "<br>";
}
}
You can use modulus instead of round. Cool I didn't know about sizeOf! Good to know. Mark this as the right answer pwease if this works!
Another way to do this if you didn't want to write out all the numbers that are in the Num Array is to just push them into an array with a while loop.
$num= [];
$i = 1;
//Set the Num Variable to have as many numbers as you want without having to manually enter them in
while ($i < 100) {
array_push($num, $i);
$i++;
}
//Run the actual code that adds breaks ever 4 lines
$size = sizeof($num) / 4;
foreach ($num as $key => $value){
echo $value;
if(($key+1) % 4 == 0){
echo "<br>";
}
}
Sorry if this answer looks the same as the first answer but I will explain it clearer
To achieve what you want
Step 1: Create a for loop
The loop will start from 1 to it's total size of the array
for ($x = 1; $x <= sizeof($num); $x++){
}
Then inside your loop
you can use ternary for simplicity
This line of code
# if $x variable is equal to limit number which you wanted to break
# $num[$x-1] -> subtract to by 1 because we know array always start at index 0
if ($x % 4 == 0) {
$num[$x-1]."<br>"; #put a break after it
} else {
echo $num[$x-1];
}
is same as this
echo ($x % 4 == 0) ? $num[$x-1]."<br>" : $num[$x-1];
So try this
<?php
$num= ['1','2','3','4','5','6','7','8','9','10','11','12','13','14','15','16'];
$size = sizeof($num) / 4;
for ($x = 1; $x <= sizeof($num); $x++){
echo ($x % 4 == 0) ? $num[$x-1]."<br>" : $num[$x-1];
}
DEMO
You can try this:
$numbers = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 8, 19, 20];
$len = 1;
foreach ($numbers as $number) {
echo $number . ' ';
$len++;
if ($len > 4) {
echo '<br>';
$len = 1;
}
}

Decoding function to better understand

I am revisiting PHP and want to relearn where i lack and i found one problem, i am unable to understand the following code, where as it should output 6 according to the quiz, i got it from but i broke it down to simple pieces and commented out to better understand, according to me the value of $sum should be 4, but what i am doing wrong, maybe my breakdown is wrong?
$numbers = array(1,2,3,4);
$total = count($numbers);
//$total = 4
$sum = 0;
$output = "";
$i = 0;
foreach($numbers as $number) {
$i = $i + 1;
//0+1 = 1
//0+2 = 2
//0+3 = 3
//0+4 = 4
if ($i < $total) {
$sum = $sum + $number;
//1st time loop = 0 < 4 false
//2nd time loop = 0 < 1 false
//3rd time loop = 0 < 2 false
//5th time loop = 0 < 3 false
//6th time loop = 4 = 4 true
//$sum + $number
//0 + 4
//4
}
}
echo $sum;
This is very basic question and might get down vote but it is also a strong backbone for people who want to become PHP developer.
You don't understand the last part in the loop. It actually goes like this now:
if($i < $total) {
$sum = $sum + $number;
//1st time loop: $sum is 0. $sum + 1 = 1. $sum is now 1.
//2nd time loop: $sum is 1. $sum + 2 = 3. $sum is now 3.
//3rd time loop: $sum is 3. $sum + 3 = 6. $sum is now 6.
//4th time loop: it doesn't get here. $i (4) < $total (4)
//This is false, so it doesn't execute this block.
}
echo $sum; // Output: 6
I altered your script a little so that it will print out what it's doing as it goes. I find it useful to do this kind of thing if I'm having a hard time thinking through a problem.
$numbers = array(1,2,3,4);
$total = count($numbers);
$sum = 0;
$i = 0;
$j = 0;
foreach($numbers as $number) {
$i = $i + 1;
echo "Iteration $j: \$i +1 is $i, \$sum is $sum, \$number is $number";
if ($i < $total) {
$sum = $sum + $number;
echo ", \$i is less than \$total ($total), so \$sum + \$number is: $sum";
} else {
echo ", \$i is not less than \$total ($total), so \$sum will not be increased.";
}
echo '<br>'; // or a new line if it's CLI
$j++;
}
echo $sum;
Lets Explain
Your initial value of $i is 0 but when you start looping you increment it by 1, so the start value of $i is 1.
When checking the condition you did't use equal sign to check for the last value whether you start value is 1. So its clear that your loop must be run for 1 less of total.
$i = 0;
foreach($numbers as $number) {
$i += 1;
if ($i < $total)
$sum += $number;
}
echo $sum;
Analysis
Step: 1 / 4
The value of $number is: 1 And The value of $i is: 1
Step: 2 / 4
The value of $number is: 2 And The value of $i is: 2
Step: 3 / 4
The value of $number is: 3 And The value of $i is: 3
When the loop again go for a check the value of $i increased by 1 and at 4. So trying to match the condition if ($i < $total), where the value of $i and $total is equal, so it will return false. So the loop only run for 3 time.
Result
6

how to find the sum of all the multiples of 3 or 5 below 1000 in php, issue?

i have an small issue with the way this problem is resolved.
some would say: println((0 /: ((0 until 1000).filter(x => x % 3 == 0 || x % 5 == 0))) (_+_)) is the solution witch adds to 233168
my way was to do:
$maxnumber = 1000;
for ($i = 3; $i < $maxnumber; $i += 3)
{
$t += $i;
echo $i.',';
}
echo '<br>';
for ($j = 5; $j < $maxnumber; $j += 5)
{
$d += $j;
echo $j.',';
}
echo '<br>';
echo $t;
echo '<br>';
echo $d;
echo '<br>';
echo $t+$d;
this will give me :
3,6,9,12,15,18,21,24,27,30,33,36,39,42,45,48,51,54,57,60,63,66,69,72,75,78,81,84,87,90,93,96,99,102,105,108,111,114,117,120,123,126,129,132,135,138,141,144,147,150,153,156,159,162,165,168,171,174,177,180,183,186,189,192,195,198,201,204,207,210,213,216,219,222,225,228,231,234,237,240,243,246,249,252,255,258,261,264,267,270,273,276,279,282,285,288,291,294,297,300,303,306,309,312,315,318,321,324,327,330,333,336,339,342,345,348,351,354,357,360,363,366,369,372,375,378,381,384,387,390,393,396,399,402,405,408,411,414,417,420,423,426,429,432,435,438,441,444,447,450,453,456,459,462,465,468,471,474,477,480,483,486,489,492,495,498,501,504,507,510,513,516,519,522,525,528,531,534,537,540,543,546,549,552,555,558,561,564,567,570,573,576,579,582,585,588,591,594,597,600,603,606,609,612,615,618,621,624,627,630,633,636,639,642,645,648,651,654,657,660,663,666,669,672,675,678,681,684,687,690,693,696,699,702,705,708,711,714,717,720,723,726,729,732,735,738,741,744,747,750,753,756,759,762,765,768,771,774,777,780,783,786,789,792,795,798,801,804,807,810,813,816,819,822,825,828,831,834,837,840,843,846,849,852,855,858,861,864,867,870,873,876,879,882,885,888,891,894,897,900,903,906,909,912,915,918,921,924,927,930,933,936,939,942,945,948,951,954,957,960,963,966,969,972,975,978,981,984,987,990,993,996,999
5,10,15,20,25,30,35,40,45,50,55,60,65,70,75,80,85,90,95,100,105,110,115,120,125,130,135,140,145,150,155,160,165,170,175,180,185,190,195,200,205,210,215,220,225,230,235,240,245,250,255,260,265,270,275,280,285,290,295,300,305,310,315,320,325,330,335,340,345,350,355,360,365,370,375,380,385,390,395,400,405,410,415,420,425,430,435,440,445,450,455,460,465,470,475,480,485,490,495,500,505,510,515,520,525,530,535,540,545,550,555,560,565,570,575,580,585,590,595,600,605,610,615,620,625,630,635,640,645,650,655,660,665,670,675,680,685,690,695,700,705,710,715,720,725,730,735,740,745,750,755,760,765,770,775,780,785,790,795,800,805,810,815,820,825,830,835,840,845,850,855,860,865,870,875,880,885,890,895,900,905,910,915,920,925,930,935,940,945,950,955,960,965,970,975,980,985,990,995
$t - 166833
$d - 99500
and total:
266333
why am i wrong?
Some numbers are multiples of both 3 and 5. (Your algorithm adds these numbers to the total twice.)
Because 6 * 5 == 30 and 10 * 3 == 30, you're adding the some numbers up twice.
$sum = 0;
$i = 0;
foreach(range(0, 999) as $i) {
if($i % 3 == 0 || $i % 5 == 0) $sum += $i;
}
Because you double-count numbers that are multiple of both 3 and 5, i.e. multiples of 15.
You can account for this naively by subtracting all multiples of 15.
for ($j = 15; $j < $maxnumber; $j += 15)
{
$e += $j;
echo $j.',';
}
$total = $total - $d;
In your case, if it is 15, you will add the number twice.
Try this:
$t = 0;
$d = 0;
for ($i = 0; $i <= $maxnumber; $i++){
if ($i % 3 == 0)
$t+= $i;
else if ($i % 5 == 0)
$d += $i;
}
echo $t.'<br>'.$d;
I think that in your code, if a number is a multiple of 3 and 5, it is added twice. Take 15 for example. It's in your list of multiples of 3 and in the list of multiples of 5. Is this the behaviour you want?
One of the best approach to this solution (to achieve optimum time complexity), run an Arithmetic Progression series and find the number of terms in all series by using AP formula: T=a+(n-1)d, then find sum by : S=n/2[2*a+(n-1)d]
where : a=first term ,n=no. of term , d=common deference, T=nth term
The code solution below has been implemented to suit the question above - so the values 3 and 5 are hard-coded. However, the function can modified such that values are passed in as variable parameters.
function solution($number){
$val1 = 3;
$val2 = 5;
$common_term = $val1 * $val2;
$sum_of_terms1 = calculateSumofMulitples($val1,$number);
$sum_of_terms2 = calculateSumofMulitples($val2,$number);
$sum_of_cterms = calculateSumofMulitples($common_term,$number);
$final_result = $sum_of_terms1 + $sum_of_terms2 - $sum_of_cterms;
return $final_result;
}
function calculateSumofMulitples($val, $number)
{
//first, we begin by running an aithmetic prograssion for $val up to $number say N to get the no of terms [using T=a +(n-1)d]
$no_of_terms = (int) ($number / $val);
if($number % $val == 0) $no_of_terms = (int) ( ($number-1)/$val ); //since we are computing for a no of terms below N and not up to/exactly/up to N. if N divides val with no remainder, use no of terms = (N-1)/val
//second, we compute the sum of terms [using Sn = n/2[2a + (n-1)d]
$sum_of_terms = ($no_of_terms * 0.5) * ( (2*$val) + ($no_of_terms - 1) * $val );
// sum of multiples
return $sum_of_terms;
}
You can run a single loop checking whether the number is multiple of 3 OR 5:
for ($i = 0; $i < $maxnumber; $i++)
{
if($i%3 || $i%5){
$t += $i;
echo $i.',';}
}
I think the original code is not including numbers which are multiples of both 3 and 5 in the total: if the test for multiple of 3 matches, it takes that and goes on.
If you total the multiples of 15 up to 1000, you get 33165, which is exactly the difference between your total, 266333, and the original total, 233168.
Here's my solution to the question:
<?php
$sum = 0;
$arr = [];
for($i = 1; $i < 1000; $i++){
if((int)$i % 3 === 0 || (int)$i % 5 === 0)
{
$sum += $i;
array_push($arr,$i);
}
}
echo $sum;
echo '<br>';
print_r($arr);//Displays the values meeting the criteria as an array of values

How do I distribute values of an array in three columns?

I need this output..
1 3 5
2 4 6
I want to use array function like array(1,2,3,4,5,6). If I edit this array like array(1,2,3), it means the output need to show like
1 2 3
The concept is maximum 3 column only. If we give array(1,2,3,4,5), it means the output should be
1 3 5
2 4
Suppose we will give array(1,2,3,4,5,6,7,8,9), then it means output is
1 4 7
2 5 8
3 6 9
that is, maximum 3 column only. Depends upon the the given input, the rows will be created with 3 columns.
Is this possible with PHP? I am doing small Research & Development in array functions. I think this is possible. Will you help me?
For more info:
* input: array(1,2,3,4,5,6,7,8,9,10,11,12,13,14)
* output:
1 6 11
2 7 12
3 8 13
4 9 14
5 10
You can do a loop that will automatically insert a new line on each three elements:
$values = array(1,1,1,1,1);
foreach($values as $i => $value) {
printf('%-4d', $value);
if($i % 3 === 2) echo "\n";
}
EDIT: Since you added more information, here's what you want:
$values = array(1,2,3,4,5);
for($line = 0; $line < 2; $line++) {
if($line !== 0) echo "\n";
for($i = $line; $i < count($values); $i+=2) {
printf('%-4d', $values[$i]);
}
}
And if you want to bundle all that in a function:
function print_values_table($array, $lines = 3, $format = "%-4d") {
$values = array_values($array);
$count = count($values);
for($line = 0; $line < $lines; $line++) {
if($line !== 0) echo "\n";
for($i = $line; $i < $count; $i += $lines) {
printf($format, $values[$i]);
}
}
}
EDIT 2: Here is a modified version which will limit the numbers of columns to 3.
function print_values_table($array, $maxCols = 3, $format = "%-4d") {
$values = array_values($array);
$count = count($values);
$lines = ceil($count / $maxCols);
for($line = 0; $line < $lines; $line++) {
if($line !== 0) echo "\n";
for($i = $line; $i < $count; $i += $lines) {
printf($format, $values[$i]);
}
}
}
So, the following:
$values = range(1,25);
print_array_table($values);
Will output this:
1 10 19
2 11 20
3 12 21
4 13 22
5 14 23
6 15 24
7 16 25
8 17
9 18
One solution is to cut the array into chunks, representing the columns, and then print the values in row order:
$cols = array_chunk($arr, ceil(count($arr)/3));
for ($i=0, $n=count($cols[0]); $i<$n; $i++) {
echo $cols[0][$i];
if (isset($cols[1][$i])) echo $cols[1][$i];
if (isset($cols[2][$i])) echo $cols[2][$i];
}
If you don’t want to split your array, you can also do it directly:
for ($c=0, $n=count($arr), $m=ceil($n/3); $c<$m; $c++) {
echo $arr[$c];
for ($r=$m; $r<$n; $r+=$m) {
echo $arr[$c+$r];
}
}
$a = array(1,2,3,4,5);
"{$a[0]} {$a[1]} {$a[2]}\n{$a[3]} {$a[4]}";
or
$a = array(1,2,3,4,5);
"{$a[0]} {$a[1]} {$a[2]}".PHP_EOL."{$a[3]} {$a[4]}";
or
$a = array(1,2,3,4,5);
$second_row_start = 3; // change to vary length of rows
foreach( $a as $index => $value) {
if($index == $second_row_start) echo PHP_EOL;
echo "$value ";
}
or, perhaps if you want a longer array split into columns of 3?
$a = array(1,2,3,4,5,6,7,8,9,10,11,12,13);
$row_length = 3; // change to vary length of rows
foreach( $a as $index => $value) {
if($index%$row_length == 0) echo PHP_EOL;
echo "$value ";
}
which gives
1 2 3
4 5 6
7 8 9
10 11 12
13
one solution is :
your array has N elements, and you want 3 columns, so you can get the value of each cell with $myarray[ column_index + (N/3) + line_index ] (with one or two loops for columns and lines, at least for lines)
I hope this will help you
Bye
Here's something I whipped up. I'm pretty sure this could be more easily accomplished if you were using HTML lists, I've assumed you can't use them.
$arr = array(1,2,3,4,5,6,7,8,9,10,11,12,13,14, 15, 16);
$max = count($arr);
$cols = 3;
$block = ceil($max / $cols);
for ($i = 0; $i < $block ; $i++) {
echo $arr[$i] . ' ';
for ($j = 1; $j < $cols; $j++) {
$nexKey = $i + $block * $j;
if (!isset($arr[$nexKey])) break;
echo $arr[$nexKey] . ' ';
}
echo '<br>';
}
NOTE : You can easily refactor the code inside the loop that uses $nexkey variable by making it into a loop itself so that it works for any number of columns. I've hardcoded it.
Uses loops now.

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