I want to generate test data for testing. What I need:
I will have a list of 30 names. For each name I need to fill in the start and finish position. The position is between 1 and 30.
So I wanted to use RAND() in php but I have a problem what I can't find a good way for.
Every position can only be used once. So if I press on a button "generate data" I want for all 30 names a start and finish position without duplicate position. So in the start i will use 1 - 30 and for the finish 1 - 30 as well.
I need this data in textfield. Is there a simple function for this? Or do you know how I can do this without having to fill in 60 textfields every test.
Something like this might get you started:
$names = array(/*...*/);
$l = count($names);
$rand = array();
for ($i = 0; $i<$l; $i++) {
$rand[] = $i;
}
shuffle($rand);
for ($i = 0; $i < $l; $i++) {
$names[$i]['start'] = $rand[$i];
}
Or:
$names = array(/*...*/);
shuffle($names);
for ($i = 0, $l = count($names); $i < $l; $i++) {
$names[$i]['start'] = $i;
}
I will use shuffle (twice),
something like
$arr = range(1, 30);
$first_numbers_position = shuffle($arr);
$second_numbers_position = shuffle($arr);
if you have already array with the names
you can use this function
Very simple shuffle function preserving key with value
function shuffle_assoc( $array )
{
$keys = array_keys( $array );
shuffle( $keys );
return array_merge( array_flip( $keys ) , $array );
}
If you don't need your code to actually generate the data dynamically you could try something like this site http://www.generatedata.com/
Related
Say I have an array like this:
$array = array('', '', 'other', '', 'other');
How can I count the number with a given value (in the example blank)?
And do it efficiently? (for about a dozen arrays with hundreds of elements each)
This example times out (over 30 sec):
function without($array) {
$counter = 0;
for($i = 0, $e = count($array); $i < $e; $i++) {
if(empty($array[$i])) {
$counter += 1;
}
}
return $counter;
}
In this case the number of blank elements is 3.
How about using array_count _values to get an array with everything counted for you?
Just an idea, you could use array_keys( $myArray, "" ) using the optional second parameter which specifies a search-value. Then count the result.
$myArray = array( "","","other","","other" );
$length = count( array_keys( $myArray, "" ));
I dont know if this would be faster but it's something to try:
$counter = 0;
foreach($array as $value)
{
if($value === '')
$counter++;
}
echo $counter;
You could also try array_reduce, with a function which would just count the value you are interested in. eg
function is_empty( $v, $w )
{ return empty( $w ) ? ($v + 1) : $v; }
array_reduce( $array, 'is_empty', 0 );
Some benchmarking might tell you if this is faster than array_count_values()
We use array_filter function to find out number of values in array
$array=array('','','other','','other');
$filled_array=array_filter($array);// will return only filled values
$count=count($filled_array);
echo $count;// returns array count
Generally for counting blanks only.
Really depends on use case and speed needed. Personally I like doing things one one line.
Like the chosen response though But you still need a line to extract the data needed though to another variable.
$r = count($x) - count(array_filter($x));
function arrayvaluecount($array) {
$counter = 0;
foreach($array as $val){
list($v)=$val;
if($v){
$counter =$counter+1;
}
}
return $counter;
}
function countarray($array)
{ $count=count($array);
return $count;
}
$test=$array = array('', '', 'other', '', 'other');
echo countarray($test);
I am trying to use a for loop where it looks through an array and tries to make sure the same element is not used twice. For example, if $r or the random variable is assigned the number "3", my final array list will find the value associated with wordList[3] and add it. When the loop runs again, I don't want $r to use 3 again. Example output: 122234, where I would want something along the lines of 132456. Thanks in advance for the help.
for($i = 0; $i < $numWords; $i++){
$r = rand(0, $numWords);
$arrayTrack[$i] == $r;
$wordList[$r] = $finalArray[$i];
for($j = 0; $j <= $i; $j++){
if($arrayTrack[$j] == $r){
# Not sure what to do here. If $r is 9 once, I do not want it to be 9 again.
# I wrote this so that $r will never repeat itself
break;
}
}
Edited for clarity.
Pretty sure you are over complicating things. Try this, using array_rand():
$final_array = array();
$rand_keys = array_rand($wordList, $numWords);
foreach ($rand_keys as $key) {
$final_array[] = $wordList[$key];
}
If $numWords is 9, this will give you 9 random, unique elements from $wordList.
See demo
$range = range(0, $numWords - 1); // may be without -1, it depends..
shuffle($range);
for($i = 0; $i < $numWords; $i++) {
$r = array_pop($range);
$wordList[$r] = $finalArray[$i];
}
I do not know why you want it.. may be it is easier to shuffle($finalArray);??
So ideally "abcdefghi" in some random order.
$letters = str_split('abcdefghi');
shuffle($letters);
var_dump($letters);
ps: if you have hardcoded array $wordList and you want to take first $n elements of it and shuffle then (if this is not an associative array and you do not care about the keys)
$newArray = array_slice($wordList, 0, $n);
shuffle($newArray);
var_dump($newArray);
You can try array_rand and unset
For example:
$array = array('one','two','free','four','five');
$count = count($array);
for($i=0;$i<$count;$i++)
{
$b = array_rand($array);
echo $array[$b].'<br />';
unset($array[$b]);
}
after you have brought the data in the array, you purify and simultaneously removing the memory array
Ok... I have NO idea why you are trying to use so many variables with this.
I certainly, have no clue what you were using $arrayTrack for.
There is a very good chance I am mis-understanding all of this though.
<?php
$numWords=10;
$wordList=array('a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z');
$finalArray=array();
for ($i=0; $i<$numWords; $i++) {
start:
$r=rand(0,$numWords);
$wordChoice=$wordList[$r];
foreach ($finalArray as $word) {
if ($word==$wordChoice) goto start;
}
$finalArray[]=$wordChoice;
}
echo "Result: ".implode(',',$finalArray)."\n";
Given the following array:
$arr = array(0,0,1,2,2,5,6,7,7,9,10,10);
And assuming $n = 2, what is the most efficient way to get a count of each value in the array within $n of each value?
For example, 6 has 3 other values within $n: 5,7,7.
Ultimately I'd like a corresponding array with simply the counts within $n, like so:
// 0,0,1,2,2,5,6,7,7,9,10,10 // $arr, so you can see it lined up
$count_arr = array(4,4,4,4,4,3,3,4,4,4, 2, 2);
Is a simple foreach loop the way to go? CodePad Link
$arr = array(0,0,1,2,2,5,6,7,7,9,10,10);
$n = 2;
$count_arr = array();
foreach ($arr as $v) {
$range = range(($v-$n),($v+$n)); // simple range between lower and upper bound
$count = count(array_intersect($arr,$range)); // count intersect array
$count_arr[] = $count-1; // subtract 1 so you don't count itself
}
print_r($arr);
print_r($count_arr);
My last answer was written without fully groking the problem...
Try sorting the array, before processing it, and leverage that when you run through it. This has a better runtime complexity.
$arr = array(0,0,1,2,2,5,6,7,7,9,10,10);
asort($arr);
$n = 2;
$cnt = count($arr);
$counts = array_pad(array(), $cnt, 0);
for ($x=0; $x<$cnt; $x++) {
$low = $x - 1;
$lower_range_bound = $arr[$x]-$n;
while($low >= 0 && ($arr[$low] >= $lower_range_bound)) {
$counts[$x]++;
$low--;
}
$high = $x + 1;
$upper_range_bound = $arr[$x]+$n;
while($high < $cnt && $arr[$high] <= $upper_range_bound) {
$counts[$x]++;
$high++;
}
}
print_r($arr);
print_r($counts);
Play with it here: http://codepad.org/JXlZNCxW
I have 2 arrays, both are multidimensional with same number of elements and same values, which are on different positions (those values are actually ID-s from my database, so one ID appears only once). How can I sort second array with values which are in first array?
For example - if first array looks like:
$array1[0][0] = 1;
$array1[0][x] = it doesn't matter what's here
$array1[1][0] = 4;
$array1[1][x] = it doesn't matter what's here
$array1[2][0] = 3;
$array1[2][x] = it doesn't matter what's here
...
how to sort second array so it would have same values as array1 on indexes [0][0], [1][0], [2][0], etc.
How I could solve problem is:
$i=0
while ($i < (count($array1)-2)){ // * check down
$find_id = $array1[$i][0];
// here I need to search for index of that ID in other array
$position = give_index($find_id, $array2);
// swapping positions
$temp = array2[$i][0];
$array2[$i][0] = $array2[$position][0];
$array2[$position][0] = $temp;
// increasing counter
i++;
}
function give_index($needle, $haystack){
for ($j = 0, $l = count($haystack); $j < $l; ++$j) {
if (in_array($needle, $haystack[$j][0])) return $j;
}
return false;
}
*There is only -2 because indexes start from 0 and also for the last element you don't need to check since it would be automatically sorted by last iteration of while-loop.
I don't find this solution good as I think that this is quite simple issue (maybe it's not even correct). Is there easier way in PHP that I'm missing?
This is the most efficient way I can think of:
function swap(&$a, &$b) {
$t = $a;
$a = $b;
$b = $t;
}
function find_index($id, $array, $from = 0) {
$index = false;
for ($i = $from, $c = count($array); $i < $c; $i++) {
if ($array[$i][0] == $id) {
$index = $i;
break;
}
}
return $index;
}
for ($i = 0, $c = count($array1); $i < ($c - 2); $i++) {
if ($array1[$i][0] != $array2[$i][0]) {
$fi = find_index($array1[$i][0], $array2, $i);
swap($array2[$i][0], $array2[$fi][0]);
}
}
What changes from yours?
I've defined a swap() function in order to swap any variable. That doesn't cost anything and makes everything look nicer. Also you can reuse that function later if you need to.
In the find_index (give_index in your code) we stop the loop once we find the correct index. Also we avoid the cost of an in_array function call.
We modified the find_index function to start only from the part of the array we haven't checked yet. Leading to a way more efficient way of scan the array.
In the for loop (a while loop was just wrong there) we stored the count of the array once, avoiding multiple calls.
Also we swap the $array2 values only if they are in the wrong place.
Other improvements
If you know anything else of the $array2 array you can make this even more performant. For example if you know that indexes are alternated like in $array1 you can change the main for loop from:
for ($i = 0, $c = count($array1); $i < ($c - 2); $i++) {
to
for ($i = 0, $c = count($array1); $i < ($c - 2); $i+2) {
(notice the $i+2 at the end) And you could do that in the find_index function as well.
Look into usort (http://php.net/manual/en/function.usort.php).
It provides a simple way to sort arrays using a user provided comparison function.
What's the fastest way to populate an array with the numbers 1-100 in PHP? I want to avoid doing something like this:
$numbers = '';
for($var i = 0; i <= 100; $i++) {
$numbers = $i . ',';
}
$numberArray = $numbers.split(',');
It seems long and tedious, is there a faster way?
The range function:
$var = range(0, 100);
range() would work well, but even with the loop, I'm not sure why you need to compose a string and split it - what's wrong with simply:
$numberArray = array();
for ($i = 0; $i < 100; $i++)
$numberArray[] = $i;