I want to parse and expand the given strings in PHP.
From
0605052&&-5&-7&-8
0605052&&-4&-7
0605050&&-2&-4&-6&-8
To
0605052, 0605053 ,0605054 ,0605055, 0605057, 0605058
0605052,0605053,0605054,0605057
0605050,0605051,0605052,0605054,0605056,0605058
can someone help me with that? thanks in advance!
Your question is not very clear, but I think you mean a solution like this:
Edited: Now the hole ranges were shown and not only the specified numbers.
<?php
$string = "0605052&&-5&-7&-8";
$test = '/^([0-9]+)\&+/';
preg_match($test, $string, $res);
if (isset($res[1]))
{
$nr = $res[1];
$test = '/\&\-([0-9])/';
preg_match_all($test, $string, $res);
$result[] = $nr;
$nrPart = substr($nr, 0, -1);
$firstPart = substr($nr, -1);
if (isset($res[1]))
{
foreach ($res[1] as &$value)
{
if ($firstPart !== false)
{
for ($i=$firstPart+1; $i<=$value; $i++)
{
$nr = $nrPart . $i;
$result[] = $nr;
}
$firstPart = false;
}
else
{
$nr = $nrPart . $value;
$result[] = $nr;
$firstPart = $value;
}
}
}
var_dump($result);
}
?>
This delivers:
result[0] = "0605052"
result[1] = "0605053"
result[2] = "0605054"
result[3] = "0605055"
result[4] = "0605057"
result[5] = "0605058"
I think a multi step approach is the best thing to do here.
E.g. take this as an example 0605052&&-5&-7&-8:
Split at -. The result will be 0605052&&, 5&, 7&, 8
The first result 0605052&& will help you create your base. Simply substring the numbers by finding first occurence of & and substring to the next to last number. Result will be 060505. You will also need the last number, so get it as well (which is 2 in this case).
Get the remaining ends now, all \d& are simple to get, simply take the first character of the string (or if those can be more than one number, use substring with first occurence of & approach again).
The last number is simple: it is 8.
Now you got all important values. You can generate your result:
The last number from 2., all numbers from 3. and the number from 4. together with your base are the first part. In addition, you need to generate all numbers from the last number of 2. and the first result of 3. in a loop by a step of 1 and append it to your base.
Example Code:
<?php
$str = '0605052&&-5&-7&-8';
$split = explode('-', $str);
$firstAmpBase = strpos($split[0], '&');
$base = substr($split[0], 0, $firstAmpBase - 1);
$firstEnd = substr($split[0], $firstAmpBase - 1, 1);
$ends = [];
$firstSingleNumber = substr($split[1], 0, strpos($split[1], '&'));
for ($i = $firstEnd; $i < $firstSingleNumber; $i++) {
array_push($ends, $i);
}
array_push($ends, $firstSingleNumber);
for ($i = 2; $i < count($split) - 1; $i++) {
array_push($ends, substr($split[$i], 0, strpos($split[$i], '&')));
}
array_push($ends, $split[count($split) - 1]);
foreach ($ends as $end) {
echo $base . $end . '<br>';
}
?>
Output:
0605052
0605053
0605054
0605055
0605057
0605058
Related
I want to group of integers (r) randomly from set of integers (n). For example n = 1,2,3,4,5,6 and r = 3, I want the output as {1,2,3} {4,5,6} so-on... but if 1 is used in one group i don't want it other group.. so-on. I want one unique combination as output. How can i do this in PHP ??
This code gives all combination without randomness
// view the real output
header('Content-Type: text/plain');
// your string
$letters = 'RAT';
// convert to array
$letters_array = array("RAT1 ", "RAT2 ", "RAT3 ", "RAT4 ", "RAT5 ","RAT6 ", "RAT7", "RAT8", "RAT9", "RAT10");
echo 'The number of two charcter combinations from that string is '.count($result = get_combos($letters_array, 3))."\n\n";
echo 'The following is the combinations array'."\n\n";
print_r(array_2d_to_1d($result));
function get_combos($input, $combo_length)
{
$input = array_values($input);
$code = '';
$cnt = count($input);
$ret = array();
$i0 = -1;
for($i=0;$i<$combo_length;++$i)
{
$k = 'i'.($i+1);
$code .= 'for($'.$k.'=$i'.$i.'+1; $'.$k.'< $cnt-'.($combo_length-$i-1).'; ++$'.$k.') ';
}
$code .= '$ret[] = array($input[$i'.implode('], $input[$i',range(1,$combo_length)).']);';
eval($code);
return $ret;
}
function str_2_array($input)
{
for($i = 0, $len = strlen($input); $i < $len; $i++)
{
$rtn[] = $input[$i];
}
return $rtn;
}
function array_2d_to_1d($input)
{
foreach($input as $key => $value)
{
$rtn[$key] = implode($value);
}
return $rtn;
}
I'm not a PHP guy so there will be no code here. But as for algorithm I think what you need is:
Optionally strip non-unique values from the source array
Perform random shuffle of the array
Slice the shuffled array into sub-arrays of required length.
This seems trivial but I'm baffled that I haven't been able to come to a solution on this. What I'm trying to do is:
Input -> 14025
Output -> 10245
Input -> 171
Output -> 117
And so on...
$input = 140205;
$temp = str_split($input);
sort($temp);
// find the 1st non-zero digit
$f = current(array_filter($temp));
// remove it from the array
unset($temp[array_search($f, $temp)]);
echo $output = $f . join($temp); // 100245
demo
A bit more verbose, but similar to previous answer
function smallestNumberFromDigits($string) {
//split string to digits
$array = str_split($string);
//sort the digits
sort($array);
//find the first digit larger than 0 and place it to the begining of array
foreach($array as $i => $digit) {
if($digit > 0) {
$tmp = $array[0];
$array[0] = $digit;
$array[$i] = $tmp;
break;
}
}
//return the imploded string back
return implode("", $array);
}
I'm trying to parse a string and delete the adjacent letters that are same. I want to return the count of number of deletions and output the resulted string after the deletions are made. Say I have
$str = "aaabbbcc";
As you can see, you need to do 5 deletions to make the adjacent letters not same. The $output string is "abc" and the number of deletions is five.
function str_deletions ($str)
{
$prev = $str[0];
$length = strlen($str);
$deletions = 0;
$output = "";
for ($i=1 ; $i < $length; $i++)
{
if ($str[$i]== $prev)
{
$deletions++;
$prev = $str[$i]; // not sure here ?
}
}
echo $output; // ?
return $deletions;
}
$str = "aabbcc";
echo str_deletions ($str);
EDIT
This is an interview question, I'm not supposed to use any built-in functions like regex or array_count_values
Thanks for your help !
Here is another regex solution. I use a regex to only match a word character that is repeated, and then remove each consecutive repeating character one by one, which allows me to use &$count argument with preg_replace:
count
If specified, this variable will be filled with the number of replacements done.
The regex is
(\w)(?=\1)
See demo. Note you can replace \w with . to match any character but a newline. OR if you need to match only letters, I suggest using '/(\p{L})(?=\1)/u'
See IDEONE demo:
$str = "aaabbbcc";
$cnt = -1;
$result = preg_replace('/(\w)(?=\1)/', "", $str, -1, $cnt);
echo "Result: " . $result . PHP_EOL . "Deletions: " . $cnt;
Output:
Result: abc
Deletions: 5
Regex solution
This is a much simpler way of doing what you're after using preg_replace():
<?php
function str_deletions($str){
$replaced = preg_replace("/(.)\\1+/", "", $str);
$length = strlen($str) - strlen($replaced);
return array("new_word" => $replaced, "chars_replaced" => $length);
}
$str = "aabbcc";
$string_deletions = str_deletions($str);
echo "New String: " . $string_deletions['new_word'] . "\n";
echo "Chars deleted: " . $string_deletions['chars_replaced'] . "\n";
?>
No inbuilt functions
For the purposes of completion (and since you updated your question with more information to say that we can't use regexes because it's an interview question), here's what I'd do:
Using count_chars():
function str_deletions($str){
$string_data['new_word'] = count_chars($str,3);
$string_data['chars_replaced'] = strlen($str) - strlen($string_data['new_word']);
return $string_data;
}
$str = "aabbcc";
echo str_deletions($str);
Note: in this example count_chars(); will return unique chars in a string, not quite remove duplicates (i.e. "aabbccaa" would still yield "abc" as an output) but your question wasn't clear what the interviewer wanted - whether it was truly a remove duplicate question or a unique char question.
Using array_unique():
Slightly slower and a bit more heavy handed:
function str_deletions($str){
$string_array = array_unique(str_split($str));
foreach($string_array as $string_cur){
$string_data['new_word'] .= $string_cur;
}
$string_data['chars_replaced'] = strlen($str) - strlen($string_data['new_word']);
return $string_data;
}
$str = "aabbcc";
echo str_deletions($str);
Note: It's worth pointing out that if I realised it was an interview question, I wouldn't have provided an answer as doing it for you kind of defeats the purpose. Still, with the amount of answers here now and the fact that I've seen something similar to this in an interview, my hope is someone will learn from these.
The basic algorithm (indeed $prev = $str[$i]; isn't at the good place but you wasn't far):
function str_deletion($str) {
$del = 0;
if (1 < $length = strlen($str)) { // $str has more than 1 char
$prev = $str[0];
$output = $prev;
for ($i=1; $i<$length; $i++) {
if ($prev == $str[$i]) {
$del++;
} else {
$prev = $str[$i]; // when different, change the previous character
$output .= $prev; // and append it to the output
}
}
} else {
$output = $str;
}
echo $output;
return $del;
}
I have changed your function
this is not returning both the output string and number of deletions
function str_deletions ($str)
{
$prev = NULL;
$deletions = 0;
$output = "";
$i=0;
while ($i < strlen($str))
{
if (substr($str,$i,1) == $prev)
{
$deletions++;
//$prev = substr($str,$i,1);/*remove this line, no need here as the same stmnt is there after ifelse*/
}else{
$output.=substr($str,$i,1);
}
$prev = substr($str,$i,1);
$i++;
}
$arr = array(
'output'=>$output,
'deletions'=>$deletions
);
return $arr;
}
$str = "aaabbcc";
print_r(str_deletions ($str));
output for above function call is
Array ( [output] => abc [deletions] => 4 )
Solved with no external function except count;
$str="aaavvvffccca";
$count = strlen($str);
for($i=0;$i<$count;$i++){
$array[]=$str[$i];
}
$del =0;
for($i=0;$i<$count;$i++){
$next=isset($array[$i+1])?$array[$i+1]:null;
if($array[$i]==$next)
{
$del++;
}
else
{
$newarray[]=$array[$i];
}
}
echo "Filter Text:". implode('',$newarray);
echo"Total Deleted:".$del;
The straight forward solution to find out the number of deletions can be
If there are N consecutive same characters delete N-1 out of those N characters.
function str_likes($str)
{
$length = strlen($str);
$del = 0;
for ($i=0 ; $i < $length ; $i++)
{
if ($str[$i] == $str[$i+1])
{
$del++;
}
}
return $del;
}
$str = "aabbccaaa";
echo str_likes($str); //4
Some time ago during a job interview I got the task to reverse a string in PHP without using strrev.
My first solution was something like this:
$s = 'abcdefg';
$temp = '';
for ($i = 0, $length = mb_strlen($s); $i < $length; $i++) {
$temp .= $s{$length - $i - 1};
}
var_dump($temp);
// outputs string(7) "gfedcba"
then they asked me if I could do this without doubling the memory usage (not using the $temp variable or any variable to copy the reversed string to) and I failed.
This kept bugging me and since then I tried to solve this multiple times but I constantly failed.
My latest try looks like this:
$s = 'abcdefg';
for ($i = 0, $length = mb_strlen($s); $i < $length; $i++) {
$s = $s{$i * 2} . $s;
}
var_dump($s);
// outputs string(14) "gfedcbaabcdefg"
It's not a solution to chop off "abcdefg" after the loop because then I would still double the amount of memory used. I need to remove the last character in every iteration of the loop.
I tried to use mb_substr like this:
$s = 'abcdefg';
for ($i = 0, $length = mb_strlen($s); $i < $length; $i++) {
$s = $s{$i * 2} . mb_substr($s, $length - $i - 1, 1);
}
var_dump($s);
but it only gives me Uninitialized string offset errors.
This is where I'm stuck (again). I tried googling but all the solutions I found either echo the characters directly or use a temporary variable.
I also found the Question PHP String reversal without using extra memory but there's no answer that fits my needs.
That's an interesting one.
Here's something I just came up with:
$s = 'abcdefghijklm';
for($i=strlen($s)-1, $j=0; $j<$i; $i--, $j++) {
list($s[$j], $s[$i]) = array($s[$i], $s[$j]);
}
echo $s;
list() can be used to assign a list of variables in one operation. So what I am doing is simply swapping characters (starting with first and last, then second-first and second-last and so on, till it reaches the middle of the string)
Output is mlkjihgfedcba.
Not using any other variables than $s and the counters, so I hope that fits your criteria.
You can use the fact that in PHP a string can be thought of as an array of characters.
Then basically what you want to do is to replace each character $i on the left side of the middle of the string with the character $j on the right side of the middle with the same distance.
For example, in a string of seven characters the middle character is on position 3. The character on position 0 (distance 3) needs to be swapped with the character on position 6 (3 + 3), the character on position 1 (distance 2) needs to be swapped with the character on position 5 (3 + 2), etc.
This algorithm can be implemented as follows:
$s = 'abcdefg';
$length = strlen($s);
for ($i = 0, $j = $length-1; $i < ($length / 2); $i++, $j--) {
$t = $s[$i];
$s[$i] = $s[$j];
$s[$j] = $t;
}
var_dump($s);
$string = 'abc';
$reverted = implode(array_reverse(str_split($string)));
You could use the XOR swap trick.
function rev($str) {
$len = strlen($str);
for($i = 0; $i < floor($len / 2); ++$i) {
$str[$i] = $str[$i] ^ $str[$len - $i - 1];
$str[$len - $i - 1] = $str[$i] ^ $str[$len - $i - 1];
$str[$i] = $str[$i] ^ $str[$len - $i - 1];
}
return $str;
}
print rev("example");
Try this:
$s = 'abcdefg';
for ($i = strlen($s)-1; $i>=0; $i--) {
$s .= $s[$i];
$s[$i] = NULL;
}
var_dump(trim($s));
Here it is PHP7 version of this:
echo "\u{202E}abcdefg"; // outs: gfedcba
PHP strings are kinda-sorta mutable, but due to copy-on-write it's very difficult to modify them in-place without a copy being made. Some of the above solutions work, but only because they're stand-alone; some already fail because they define a function without a pass-by-reference argument. To get the code to actually operate in-place in a larger program, you'd need to pay careful attention to assignments, function arguments, and scopes.
Example:
$string1 = 'abc';
$string2 = $string1;
$string1[0] = 'b';
print("$string1, $string2");
> "abc, bbc"
I suppose that if between initializing the variable and modifying it you only ever used by-reference assignments (&=) and reference arguments (function rev(&$string)) (or assign the string to an object property initially, and then never assign it to any other variable), you might be able to change the original value of the string without making any copies. That's a bit ridiculous, however, and I'd assume that the interviewer who came up with that question didn't know about copy-on-write.
This isn't quite the same as immutability in other languages, by the way, because it applies to arrays too:
$a = [0, 1, 2];
$b = $a;
$b[0] = 1;
print(implode($a).implode($b));
> "012112"
To sum up, all types (except for objects as of PHP5) are assigned with copy-on-write unless you specifically use the &= operator. The assignment doesn't copy them, but unlike most other languages (C, Java, Python...) that either change the original value (arrays) or don't allow write access at all (strings), PHP will silently create a copy before making any changes.
Of course, if you switched to a language with more conventional pointers and also switched to byte arrays instead of strings, you could use XOR to swap each pair of characters in place:
for i = 0 ... string.length / 2:
string[i] ^= string[string.length-1-i]
string[string.length-1-i] ^= string[i]
string[i] ^= string[string.length-1-i]
Basically #EricBouwers answer, but you can remove the 2nd placeholder variable $j
function strrev2($str)
{
$len = strlen($str);
for($i=0;$i<$len/2;$i++)
{
$tmp = $str[$i];
$str[$i] = $str[$len-$i-1];
$str[$len-$i-1] = $tmp;
}
return $str;
}
Test for the output:
echo strrev2("Hi there!"); // "!ereht iH"
echo PHP_EOL;
echo strrev2("Hello World!"); // "!dlroW olleH"
This will go through the list and stop halfway, it swaps the leftmost and rightmost, and works it's way inward, and stops at the middle. If odd numbered, the pivot digit is never swapped with itself, and if even, it swaps the middle two and stops. The only extra memory used is $len for convenience and $tmp for swapping.
If you want a function that doesn't return a new copy of the string, but just edits the old one in place you can use the following:
function strrev3(&$str)
{
$len = strlen($str);
for($i=0;$i<$len/2;$i++)
{
$tmp = $str[$i];
$str[$i] = $str[$len-$i-1];
$str[$len-$i-1] = $tmp;
}
}
$x = "Test String";
echo $x; // "Test String"
strrev3($x);
echo PHP_EOL;
echo $x; // "gnirtS tseT"
Using &$str passes a direct pointer the the string for editing in place.
And for a simpler implementation like #treegardens, you can rewrite as:
$s = 'abcdefghijklm';
$len = strlen($s);
for($i=0; $i < $len/2; $i++) {
list($s[$i], $s[$len-$i-1]) = array($s[$len-$i-1], $s[$i]);
}
echo $s;
It has the similar logic, but I simplified the for-loop quite a bit.
Its Too Simple
//Reverse a String
$string = 'Basant Kumar';
$length = strlen($string);
for($i=$length-1;$i >=0;$i--){
echo $string[$i];
}
Here is my code to solve your problem
<?php
$s = 'abcdefg';
for ($i = 0, $length = mb_strlen($s); $i < $length; $i++) {
$s = $s{$i}.mb_substr($s,0,$i).mb_substr($s,$i+1);
}
var_dump($s);
?>
You could also use a recursion to reverse the string. Something like this for example:
function reverse($s) {
if(strlen($s) === 1) return $s;
return substr($s, strlen($s)-1) . reverse(substr($s , 0, strlen($s)-1));
}
What you do here is actually returning the last character of the string and then calling again the same function with the substring that contains the initial string without the last character. When you reach the point when your string is just one character then you end the recursion.
You can use this code to reverse a string without using the reserved function in php.
Code:
<?php
function str_rev($y)// function for reversing a string by passing parameters
{
for ($x = strlen($y)-1; $x>=0; $x--) {
$y .= $y[$x];
$y[$x] = NULL;
}
echo $y;
}
str_rev("I am a student");
?>
Output:
tneduts a ma I
In the above code, we have passed the value of the string as the parameter.We have performed the string reversal using for loop.
you could use substr with negative start.
Theory & Explanation
you can start with for loop with counter from 1 to length of string, and call substr inside iteration with counter * -1 (which will convert the counter into negative value) and length of 1.
So for the first time counter would be 1 and by multiplying with -1 will turn it to -1
Hence substr('abcdefg', -1, 1); will get you g
and next iteration substr('abcdefg', -2, 1); will get you f
and substr('abcdefg', -3, 1); will get you e
and so on ...
Code
$str = 'abcdefghijklmnopqrstuvwxyz';
for($i=1; $i <= strlen($str); $i++) {
echo substr($str, $i*-1, 1);
}
In Action: https://eval.in/583208
public function checkString($str){
if(!empty($str)){
$i = 0;
$str_reverse = '';
while(isset($str[$i])){
$strArr[] = $str[$i];
$i++;
}
for($j = count($strArr); $j>= 0; $j--){
if(isset($strArr[$j])){
$str_reverse .= $strArr[$j];
}
}
if($str == $str_reverse){
echo 'It is a correct string';
}else{
echo 'Invalid string';
}
}
else{
echo 'string not found.';
}
}
//Reverse String word by word
$str = "Reverse string word by word";
$i = 0;
while ($d = $str[$i]) {
if($d == " ") {
$out = " ".$temp.$out;
$temp = "";
}
else
$temp .= $d;
$i++;
}
echo $temp.$out;
The following solution is very simple, but it does the job:
$string = 'Andreas';
$reversedString = '';
for($i = mb_strlen($string) - 1; $i >= 0; $i--){
$reversedString .= $string[$i];
}
var_dump($reversedString) then results: string(7) "saerdnA"
<?php
$value = 'abcdefg';
$length_value = strlen($value);
for($i = $length_value-1; $i >=0 ;$i--){
echo $value[$i];
}
?>
you can try this..
$string = "NASEEM";
$total_word = strlen($string);
for($i=0; $i<=$total_word; $i++)
{
echo substr($string,$total_word-$i,1);
}
i have used some built in function but without str_rev function .
<?php
$text = "red";
$arr = str_split($text);
$rev_text = array_reverse($arr);
echo join(" ",$rev_text);
?>
Try This
<?php
$str="abcde";
for($i=strlen($str)-1;$i>=0;$i--){
echo $str[$i];
}
?>
output
edcba
This is my solution to solve this.
$in = 'This is a test text';
$out = '';
// find string length
$len = strlen($in);
// loop through it and print it reverse
for ( $i = $len - 1; $i >=0;$i-- )
{
$out = $out.$in[$i];
}
echo $out;
Reverse string using recursion function.
$reverseString = '';
function Reverse($str, $len)
{
if ($len == 0) {
return $GLOBALS['reverseString'];
} else {
$len--;
$GLOBALS['reverseString'] .= $str[$len];
return Reverse($str, $len);
}
}
$str = 'Demo text';
$len = strlen($str);
echo Reverse($str, $len)
Try this
$warn = 'this is a test';
$i=0;
while(#$warn[$i]){
$i++;}
while($i>0)
{
echo $warn[$i-1]; $i--;
}
I have a string like this:
$string = "1,4|2,64|3,0|4,18|";
Which is the easiest way to access a number after a comma?
For example, if I have:
$whichOne = 2;
If whichOne is equal to 2, then I want to put 64 in a string, and add a number to it, and then put it back again where it belongs (next to 2,)
Hope you understand!
genesis'es answer with modification
$search_for = 2;
$pairs = explode("|", $string);
foreach ($pairs as $index=>$pair)
{
$numbers = explode(',',$pair);
if ($numbers[0] == $search_for){
//do whatever you want here
//for example:
$numbers[1] += 100; // 100 + 64 = 164
$pairs[index] = implode(',',$numbers); //push them back
break;
}
}
$new_string = implode('|',$pairs);
$numbers = explode("|", $string);
foreach ($numbers as $number)
{
$int[] = intval($number);
}
print_r($int);
$string = "1,4|2,64|3,0|4,18|";
$coordinates = explode('|', $string);
foreach ($coordinates as $v) {
if ($v) {
$ex = explode(',', $v);
$values[$ex[0]] = $ex[1];
}
}
To find the value of say, 2, you can use $whichOne = $values[2];, which is 64
I think it is much better to use the foreach like everyone else has suggested, but you could do it like the below:
$string = "1,4|2,64|3,0|4,18|";
$whichOne = "2";
echo "Starting String: $string <br>";
$pos = strpos($string, $whichOne);
//Accomodates for the number 2 and the comma
$valuepos = substr($string, $pos + 2);
$tempstring = explode("|", $valuepos);
$value = $tempstring[0]; //This will ow be 64
$newValue = $value + 18;
//Ensures you only replace the index of 2, not any other values of 64
$replaceValue = "|".$whichOne.",".$value;
$newValue = "|".$whichOne.",".$newValue;
$string = str_replace($replaceValue, $newValue, $string);
echo "Ending String: $string";
This results in:
Starting String: 1,4|2,64|3,0|4,18|
Ending String: 1,4|2,82|3,0|4,18|
You could run into issues if there is more than one index of 2... this will only work with the first instance of 2.
Hope this helps!
I know this question is already answered, but I did one-line solution (and maybe it's faster, too):
$string = "1,4|2,64|3,0|4,18|";
$whichOne = 2;
$increment = 100;
echo preg_replace("/({$whichOne},)(\d+)/e", "'\\1'.(\\2+$increment)", $string);
Example run in a console:
noice-macbook:~/temp% php 6642400.php
1,4|2,164|3,0|4,18|
See http://us.php.net/manual/en/function.preg-replace.php