$arr = ["250","250","500","500","250"];
Here is my $arr array. I want to replace 300 instead of 500.
Sample:
["250","250","300","300","250"]; //Output
Here is my code
$length = sizeof($arr);
for($i = 0; $i < $length; $i++)
{
if($arr[$i] <= 300)
{
}
else
{
$replace = array($i => "300");
array_replace($arr, $replace);
}
}
You should use the str_replace() function, that allows you to replace a value with another one in both strings and arrays.
In your case it would be:
$arr = str_replace("500","300",$arr);
you could use array_replace(), but it works not by value, rather by position, and array_replace() returns a new array rather than mutating the original one.
you could modify the else part of your code like below, since you were not using the modified array;
....
....
else
{
$replace = array($i => "300");
$arr2 = array_replace($arr, $replace);
var_dump($arr2);//this holds the replaced array
}
Related
i have some problem.
i just want my loop to run, but when i try to do it, it fails, it has to increment each letter by a few, but it doesn't take any new letters at all, why is this happening and what is the reason? in c ++ such code would work.
function accum('ZpglnRxqenU') {
// your code
$result = '';
$letters_result = '';
$letter_original = '';
$num_if_str = strlen($s);
$j = 0;
for ( $i=0; $i <= $num_if_str; $i++ )
{
$letter_original = substr($s, $i, $i+1);
$j = 0;
while($j == $i)
{
$letters_result = $letters_result . $letter_original;
$j++;
}
if($i != strlen($s))
{
$letters_result = $letters_result . '-';
}
}
return $letters_result;
}
It returns
- Expected: 'Z-Pp-Ggg-Llll-Nnnnn-Rrrrrr-Xxxxxxx-Qqqqqqqq-Eeeeeeeee-Nnnnnnnnnn-Uuuuuuuuuuu'
Actual : 'Z-----------'
what problem with what PHP code?
There are a number of problems here:
you're using $s but never initialise it
Your call to substr() uses an incorrect value for the length of substring to return
you're inner loop only runs while $i = $j, but you initialise $j to 0 so it will only run when $i is zero, i.e. for the first letter of the string.
There is a simpler way to do this. In PHP you can address individual characters in a string as if they were array elements, so no need for substr()
Further, you can use str_repeat() to generate the repeating strings, and if you store the expanded strings in an array you can join them all with implode().
Lastly, combining ucwords() and strtolower() returns the required case.
Putting it all together we get
<?php
$str = "ZpglnRxqenU";
$output = [];
for ($i = 0;$i<strlen($str);$i++) {
$output[] = str_repeat($str[$i], $i+1);
}
$output = ucwords(strtolower(implode('-',$output)),"-");
echo $output; // Z-Pp-Ggg-Llll-Nnnnn-Rrrrrr-Xxxxxxx-Qqqqqqqq-Eeeeeeeee-Nnnnnnnnnn-Uuuuuuuuuuu
Demo:https://3v4l.org/OoukZ
I don't have much more to add to #TangentiallyPerpendicular's answer as far as critique, other than you've made the classic while($i<=strlen($s)) off-by-one blunder. String bar will have a length of 3, but arrays are zero-indexed [eg: [ 0 => 'b', 1 => 'a', '2' => 'r' ]] so when you hit $i == strlen() at 3, that's an error.
Aside from that your approach, when corrected and made concise, would look like:
function accum($input) {
$result = '';
for ( $i=0, $len=strlen($input); $i < $len; $i++ ) {
$letter = substr($input, $i, 1);
for( $j=0; $j<=$i; $j++ ) {
$result .= $letter;
}
if($i != $len-1) {
$result .= '-';
}
}
return $result;
}
var_dump(accum('ZpglnRxqenU'));
Output:
string(76) "Z-pp-ggg-llll-nnnnn-RRRRRR-xxxxxxx-qqqqqqqq-eeeeeeeee-nnnnnnnnnn-UUUUUUUUUUU"
Also keep in mind that functions have their own isolated variable scope, so you don't need to namespace variables like $letters_foo which can make your code a bit confusing to the eye.
So I'm getting a lot of these errors when I run this code. I'm about to give up and just use the sorting functions baked into PHP. But I would love if anyone could see the problem here. Please see below code. Sorry in advance if it's hard to read.
The array input is fine as print_r outputs exactly as expected, but the actual sorting algorithm just won't work, no matter what I try. The two commented functions at the bottom were used in different trials.
<?php
//this function will pull a string from a txt file and pass characters to an array
function strToArray($file){
if ($handle = fopen($file, 'r')){
$string = fread($handle, filesize($file));
fclose($handle);
}
$strArray = str_split(preg_replace('/\s+/', '', $string)); //regex in preg_replace gets rid of all whitespaces; str_split converts string to array
$arrLen = array_count_values($strArray);
return $arrLen;
}
$arrayWithVal = strToArray("filetest.txt"); //intermediary to pass into next function
print_r($arrayWithVal); //see what I have so far
echo "<hr />";
$newArray = $arrayWithVal;
for ($i = 1; $i < count($newArray); $i++){
for ($j = $i-1; $j >= 0; $j--){
if ($newArray[$j] > $newArray[$j+1]){ //if value on left is bigger than current value
$oldValue = $newArray[$j+1];
$newArray[$j+1] = $newArray[$j];
$newArray[$j] = $oldValue;
//return $newArray;
}
else {
break; //if value on left is smaller, skip to next position
}
}
}
print_r($newArray); //END
/*
function insertionSort($array){
$newArray=$arrayWithVal;
for($j=1; $j < count($newArray); $j++){
$temp = $newArray[$j];
$i = $j;
while(($i >= 0) && ($newArray[$i-1] > $temp)){
$newArray[$i] = $newArray[$i-1];
$i--;
}
$newArray[$i] = $temp;
}
return $array;
}
*/
/*
function insertionSort($arrData){
for ($i=1;$i<count($arrData);$i++){
for ($j=$i-1;$j>=0;$j--){
if ($arrData[$j]>$arrData[$j+1]){ //if value on left is bigger than current value
$oldValue = $arrData[$j+1];
$arrData[$j+1] = $arrData[$j];
$arrData[$j] = $oldValue;
}
else {
break; //if value on left is smaller, skip to next position
}
}
}
return $arrData;
}
*/
?>
EDIT: I should also mention that after it returns the errors, it prints the the same array that the first print_r output.
You are using array_count_values($strArray) function which will return an array using the values of $strArray as keys and their frequency in $strArray as values.
So for ex:
$arrayWithVal will be:
array('some_word'=>3,'other_word'=>4);
You are copying this array into $newArray and then later on you are trying to access $newArray with numeric index : $newArray[$j+1] while $newArray is an associative array.
That is why you are getting undefined offset error.
Exact working code for your problem can be :
//this function will pull a string from a txt file and pass characters to an array
function strToArray($file){
if ($handle = fopen($file, 'r')){
$string = fread($handle, filesize($file));
fclose($handle);
}
$strArray = str_split(preg_replace('/\s+/', '', $string)); //regex in preg_replace gets rid of all whitespaces; str_split converts string to array
$arrLen = array_count_values($strArray);
return $arrLen;
}
$arrayWithVal = strToArray("filetest.txt"); //intermediary to pass into next function
print_r($arrayWithVal); //see what I have so far
$newArray = $arrayWithVal;
$test = array();
foreach($newArray as $v){
$test[] = $v;
}
for ($i = 1; $i < count($test); $i++){
for ($j = $i-1; $j >= 0; $j--){
if ($test[$j] > $test[$j+1]){ //if value on left is bigger than current value
$oldValue = $test[$j+1];
$test[$j+1] = $test[$j];
$test[$j] = $oldValue;
//return $newArray;
}
else {
break; //if value on left is smaller, skip to next position
}
}
}
$result = array();
foreach($test as $k => $v){
$keys_array = array_keys($newArray, $v);
foreach($keys_array as $key){
$result[$key] = $v;
}
}
print_r($result);// to see $result array
If your $newArray is:
Array
(
[some] => 4
[r] => 3
[w] => 6
[t] => 1
[a] => 8
[hell] => 4
)
$result array will be :
Array
(
[t] => 1
[r] => 3
[some] => 4
[hell] => 4
[w] => 6
[a] => 8
)
Its good approach if you are learning PHP but otherwise you should just use inbuild php functions for better time performance.
I hope it helps
So I have an array:
$array = array('Sun','Mon','Tue','Wed','Thu','Fri','Sat');
Obviously they're indexed 0-6.
I want to feed in a specific key index, and then reorder the array, beginning with that key, then going through the rest in the same order, like so:
print_r(somefunction(3, $array));
which would print this:
array
(
'0'=>'Wed',
'1'=>'Thu',
'2'=>'Fri',
'3'=>'Sat',
'4'=>'Sun',
'5'=>'Mon',
'6'=>'Tue'
)
Is there a core function that would do this, or does anyone have a quick solution?
UPDATE
Here's my final function, slightly bigger in scope than my question above, which utilizes AbraCadaver's answer:
public static function ordered_weekdays($format = 'abr')
{
$array = $format == 'full' ? array('Sunday','Monday','Tuesday','Wednesday','Thursday','Friday','Saturday') : array('Sun','Mon','Tue','Wed','Thu','Fri','Sat');
return array_merge(array_splice($array, get_option('start_of_week'), count($array)-1), $array);
}
Because it's a nice one-liner, I didn't need to make it a separate function.
I've done this before and thought it was simpler than this, but here is what my brain says at the moment:
$index = 3;
$array = array_merge(array_splice($array, $index, count($array)-1), $array);
Try something along these lines...
function reorder($x,$y)
{
$c = count($y);
for ($i=0; $i<$c; $i++)
{
$newArray[$i] = $y[$x];
$x++;
if ($x > $c) $x = 0;
}
return($newArray);
}
function somefunction($n, array $a) {
$x = array_slice($a, 0, $n);
$y = array_slice($a, $n);
return array_merge($y, $x);
}
// forget this: uneccessary looping...
function somefunction($n, array $a) {
for($i = 0; $i < $n; $i++) {
array_push($a, array_shift($a));
}
return $a;
}
I am trying to create arrays dynamically and then populate them by constructing array Names using variable but I am getting the following warnings
Warning: in_array() expects parameter 2 to be array, null given
Warning: array_push() expects parameter 1 to be array, null given
For single array this method worked but for array of arrays this is not working. How should this be done?
<?php
for ($i = 1; $i <= 23; ++$i)
{
$word_list[$i] = array("1");
}
for ($i = 1; $i <= 23; ++$i)
{
$word = "abc";
$arrayName = "word_list[" . $i . "]";
if(!in_array($word, ${$arrayName}))
{
array_push($$arrayName , $word);
}
}
?>
Why are even trying to put array name in a variable and then de-reference that name? Why not just do this:
for ($i = 1; $i <= 23; ++$i)
{
$word = "abc";
$arrayName = "word_list[" . $i . "]";
if(!in_array($word, $word_list[$i]))
{
array_push($word_list[$i] , $word);
}
}
You get the first warning because your $arrayName variable is not actually an array, you made it into a string.
So instead of:
$arrayName = "word_list[" . $i . "]";
You should have this:
$arrayName = $word_list[$i];
You get your second warning because your first parameter is not an array.
So instead of:
array_push($$arrayName , $word);
You should have this:
array_push($arrayName , $word);
If you make these changes you will get an array that looks like this in the end:
$wordlist = array( array("1", "abc"), array("1", "abc"), ... ); // repeated 23 times
And in the for loop, you are accessing the array the wrong way
Here is your corrected code
for ($i = 1; $i <= 23; ++$i)
{
$word = "abc";
$arrayName = $word_list[$i];
if(!in_array($word, $arrayName))
{
array_push($arrayName , $word);
$word_list[$i] = $arrayName;
}
}
Say I have this array:
$array[] = 'foo';
$array[] = 'apple';
$array[] = '1234567890;
I want to get the length of the longest string in this array. In this case the longest string is 1234567890 and its length is 10.
Is this possible without looping through the array and checking each element?
try
$maxlen = max(array_map('strlen', $ary));
Sure:
function getmax($array, $cur, $curmax) {
return $cur >= count($array) ? $curmax :
getmax($array, $cur + 1, strlen($array[$cur]) > strlen($array[$curmax])
? $cur : $curmax);
}
$index_of_longest = getmax($my_array, 0, 0);
No loop there. ;-)
A small addition to the ticket. I came here with a similar problem: Often you have to output just the longest string in an array.
For this, you can also use the top solution and extend it a little:
$lengths = array_map('strlen', $ary);
$longestString = $ary[array_search(max($lengths), $lengths)];
Loop through the arrays and use strlen to verify if the current length is longer than the previous.. and save the index of the longest string in a variable and use it later where you need that index.
Something like this..
$longest = 0;
for($i = 0; $i < count($array); $i++)
{
if($i > 0)
{
if(strlen($array[$i]) > strlen($array[$longest]))
{
$longest = $i;
}
}
}
This way you can find the shortest (or longest) element, but not its index.
$shortest = array_reduce($array, function ($a, $b) {
if ($a === null) {
return $b;
}
return strlen($a) < strlen($b) ? $a : $b;
});