If I have this pattern to build ID's:
CX00 where the 0's are replaceable with just a number.. but the following is already in use:
- CX00
- CX02
- CX04
- CX05
- CX07
- CX10
- CX11
- CX12
How can I easily find, either via PHP or MySQL the values CX01, CX03, CX06, CX08, CX09, CX13+ as available values?
I don't know how your data is stored, so I'll leave getting the IDs in an array. Once you do, this will find the next available one.
<?php
function make_id($n) {
$out = 'CX';
if ($n < 10) $out .= '0';
return $out . $n;
}
// Get these from some source
$items = array('CX00', 'CX02', 'CX04', 'CX05');
$id = make_id(0);
for($i=0; in_array($id, $items); $i++)
$id = make_id($i);
echo $id;
?>
This is called a brute-force method, and if you have a lot of IDs there are probably more efficient ways. With 100 maximum, there shouldn't be any problems.
In php simply count up through the ids using a for loop until you have found enough of the unused ids... how many total ids do you expect to have?
Related
I'm working on a project, and it has a bunch of variables for some links that I define. But I want to add a string at the end of those variable only if I got some GET parameters. The thing is I don't want to have another huge amount of variables and I want to have the same name for the variables. After some research, I came with this operator .= which is perfect for me. I also made a for loop it works well for the variable value, but I don't have the same name.
Here is what I got:
$homeLink = $wURL.'government/'.$job.'/';
$databaseLink = $wURL.'government/'.$job.'/search/database';
$overviewLink = $wURL.'government/'.$job.'/overview';
// Other variables
if (!isset($_SESSION['steamid']) && isset($_GET['uID']) && isset($_GET['uToken'])) {
// redefine the variables like this:
$homeLink .= '?uID='.$userinfoVlife['id'].'&uToken='.$userinfoVlife['websiteMDP'];
/*
OUTPUT: $wURL.'government/'.$job.'/'.'?uID='.$userinfoVlife['id'].'&uToken='.$userinfoVlife['websiteMDP']
*/
// The for loop:
$arr = array($homeLink,$databaseLink,$overviewLink);
$nb = count($arr);
for ($i=0; $i < $nb ; $i++) {
$arr[$i] .= '?uID='.$userinfoVlife['id'].'&uToken='.$userinfoVlife['websiteMDP'];
echo $arr[$i]."<br>";
// have the same output that above but I have to call my variables with $arr[<a number>];
}
}
The thing is I don't want to have another huge amount of variables and I want to have the same name for the variables, any ideas on how I can proceed?
First, your 2 last links are actually both based on the first one, $homeLink:
$homeLink = $wURL.'government/'.$job.'/';
$databaseLink = $homeLink.'search/database';
$overviewLink = $homeLink.'overview';
then why not build the parameter string and then append it?
$homeLink = $wURL.'government/'.$job.'/'
$paramString = '';
if (!isset($_SESSION['steamid']) && isset($_GET['uID']) && isset($_GET['uToken'])) {
$paramString = '?uID='.$userinfoVlife['id'].'&uToken='.$userinfoVlife['websiteMDP'];
}
$databaseLink = $homeLink.'search/database'.$paramString;
$overviewLink = $homeLink.'overview'.$paramString;
$homeLink .= $paramString;
I don't get why you want to store your URLs in an array, these are different URLs, thus to be used in different contexts, having all of them in one array is of course possible but doesn't bring any value, in my opinion.
To conclude, if $userinfoVlife['websiteMDP'] contains a readable password, you definitely have a problem in your application architecture: it's very bad practice to handle raw passwords and it's even worse to pass it in the URL.
I'm working on a 'thought' function for a game i'm working on -- it pulls random strings from an XML file, combines them and makes them 'funny'. However, i'm running into a small issue in that the same couple of items keep getting selected each time.
The two functions I am using are
function randRoller($number)
{
mt_srand((microtime()*time())/3.145);
$x = [];
for($i = 0; $i < 100; $i++)
{
#$x = mt_rand(0,$number);
}
return mt_rand(0,$number);
}
/* RETRIEVE ALL RELEVANT DATA FROM THE XML FILE */
function retrieveFromXML($node)
{
$node = strtolower($node);
$output = [];
$n = substr($node,0,4);
#echo $node;
foreach($this->xml->$node->$n as $data)
{
$output[] = $data->attributes();
}
$count = count($output)-1;
$number = $this->randRoller($count);
return $output[$number];
}
Granted, the "randRoller" function is sorta defunct now because the orginal version I had (Which 'rolled' ten numbers from the count, and then selected the one which got the most number of dice) didn't work as planned.
I've tried everything i can think of to get better results && have googled my brains out to fix it. but still am getting the same repetitive results.
Don't use mt_srand() unless you know what you are doing, since it is called automatically. See the note on http://php.net/manual/en/function.mt-srand.php:
Note: There is no need to seed the random number generator with srand() or mt_srand() as this is done automatically.
Remove (all) the mt_srand() call(s).
So crazy! I have a bug that's 100% reproducible, it happens in only a few lines of code, yet I cannot for the life of me determine what the problem is.
My project is a workout maker, and the mystery involves two functions:
get_pairings: It makes a set of $together_pairs (easy) and $mixed_pairs (annoying), and combines them into $all_pairs, used to make the workout.
make_mixed_pairs: this has different logic depending on whether it's a partner vs solo workout. Both cases return a set of $mixed_pairs (in the same exact format), called by the function above.
The symptoms/clues:
The case of the solo workout is fine, $all_pairs will only contain $mixed_pairs (because as it's defined, $together_pairs are only for partner workouts)
In the case of the a partner workout, when I combine the two sets in get_pairings(), $all_pairs only successfully gets the first set I give it! (If I swap those lines at step 2 and add $together_pairs first, $all_pairs contains only those. If I do $mixed_pairs first, $all_pairs contains only that).
Then if I uncomment that second-to-last line in make_mixed_pairs() just for troubleshooting to see what happens, then $all_pairs does successfully include exercises from both sets!
That suggests the problem is something I'm doing wrong in making the arrays in make_mixed_pairs(), but I confirmed that the resulting format is identical in both cases.
Anyone see what else I could be missing? I've been narrowing down this bug for 4 hours so far- I can't make it any smaller, and I can't see what's wrong :(
Update: I updated the for loop in make_mixed_pairs() to stop at $mixed_pair_count - 1 (instead of just $mixed_pair_count), and now I sometimes get one single 'together_pair' mixed in the $all_pairs results; the same damn one each time, weirdly. Though it's not 'fixed', because again when I change the order that I add the two sets in get_pairings, when I add $together_pairs first, then $all_pairs is ENTIRELY those- it's so strange...
Here are the functions: first get_pairings (relevant part is right before and after step 2):
/**
* Used in make_workout.php: take the user's available resources, and return valid exercises
*/
function get_pairings($exercises, $count, $outdoor_partner_workout)
{
// 1. Prep our variables, and put exercises into the appropriate buckets
$mixed_exercises = array();
$together_pairs = array();
$mixed_pairs = array();
$all_pairs = array();
$selected_pairs = array();
// Sort the valid exercises: self_pairing exercises go as they are, with extra
// array for consistent formatting. Mixed ones go into $mixed_exercises array
// for more specialized pairing in make_mixed_pairs
foreach($exercises as $exercise)
{
if ($exercise['self_pairing'])
{
$pair = array($exercise);
array_push($together_pairs, [$pair]);
}
else
{
$this_exercise = array($exercise);
array_push($mixed_exercises, $this_exercise);
}
}
// Now get the mixed_pairs
$mixed_pairs = make_mixed_pairs($mixed_exercises, $outdoor_partner_workout);
// 2. combine together into one set, and select random pairs for the workout
// Add both sets to the array of all pairs (to pick from afterward)
$all_pairs += $mixed_pairs;
$all_pairs += $together_pairs;
// Now let's choose at random our desired # of pairs, and save them in $selected_pairs
$pairing_keys = array_rand($all_pairs, $count);
foreach($pairing_keys as $key)
{
array_push($selected_pairs, $all_pairs[$key]);
}
// Finally, shuffle it so we don't always see the self-pairs first
shuffle($selected_pairs);
return $selected_pairs;
}
And the other one- make_mixed_pairs: there are two cases, the first is complicated (and shows the bug) and the second is simple (and works):
/**
* Used by get_pairings: in case of a partner workout that has open space (where
* one person can travel to a point while the other does an exercise til they return)
* we'll pair exercises in a special way. (If not, fine to grab random pairs)
*/
function make_mixed_pairs($mixed_exercises, $outdoor_partner_workout)
{
$mixed_pairs = array();
// When it's an outdoor partner workout, we want to pair travelling with stationary
// put them into arrays and then we'll make pairs using one from each
if ($outdoor_partner_workout)
{
$mixed_travelling = array();
$mixed_stationary = array();
foreach($mixed_exercises as $exercise)
{
if ($exercise[0]['travelling'])
{
array_push($mixed_travelling, $exercise);
}
else
{
array_push($mixed_stationary, $exercise);
}
}
shuffle($mixed_travelling);
shuffle($mixed_stationary);
// determine the smaller set, and pair exercises that many times
$mixed_pair_count = min(count($mixed_travelling), count($mixed_stationary));
for ($i=0; $i < $mixed_pair_count; $i++)
{
$this_pair = array($mixed_travelling[$i], $mixed_stationary[$i]);
array_push($mixed_pairs, $this_pair); // problem is adding them here- we get only self_pairs
}
}
// Otherwise we can just grab pairs from mixed_exercises
else
{
// shuffle the array so it's in random order, then chunk it into pairs
shuffle($mixed_exercises);
$mixed_pairs = array_chunk($mixed_exercises, 2);
}
// $mixed_pairs = array_chunk($mixed_exercises, 2); // when I replace it with this, it works
return $mixed_pairs;
}
Oh for Pete's sake: I mentioned this to a friend, who told me that union is flukey in php, and that I should use array_merge instead.
I replaced these lines:
$all_pairs += $together_pairs;
$all_pairs += $mixed_pairs;
with this:
$all_pairs = array_merge($together_pairs, $mixed_pairs);
And now it all works
there. I'm having a problem with creating arrays in certain conditions in php, i'll try to explain. Here's my code:
for ($i = 1; $i < $tamanho_array_afundamento; $i++) {
if ($array_afundamento[$i] - $array_afundamento[$i - 1] > 1) {
$a = $array_afundamento[$i - 1];
$con->query('CREATE TABLE IF NOT EXISTS afunda_$a
SELECT (L1_forma_tensao_max + L1_forma_tensao_min)/2 as L1_forma_tensao, (L2_forma_tensao_max + L2_forma_tensao_min)/2 as L2_forma_tensao, (L3_forma_tensao_max + L3_forma_tensao_min)/2 as L3_forma_tensao
FROM afundamento
WHERE id > $prevNum AND id < $a');
$tabelas_intervalos_afunda1 = ($con->query("SELECT * FROM afunda_$a");
while ($row = $tabelas_intervalos_afunda->fetch(PDO::FETCH_ASSOC)) {
$array_forma_onda_fase1_afund[] = $row['L1_forma_tensao'];
$array_forma_onda_fase2_afund[] = $row['L2_forma_tensao'];
$array_forma_onda_fase3_afund[] = $row['L3_forma_tensao'];
}
$prevNum = $a;
}
}
So as u can see, i have an if statement in a for loop, what i'm wishing to do is to create
one set of:
{
$array_forma_onda_fase1_afund[] = $row['L1_forma_tensao'];
$array_forma_onda_fase2_afund[] = $row['L2_forma_tensao'];
$array_forma_onda_fase3_afund[] = $row['L3_forma_tensao'];
}
every time the if statement is runned. I was trying replacing this in the original code:
{
$array_forma_onda_fase1_afund_$a[] = $row['L1_forma_tensao'];
$array_forma_onda_fase2_afund_$a[] = $row['L2_forma_tensao'];
$array_forma_onda_fase3_afund_$a[] = $row['L3_forma_tensao'];
}
so as $a is changed everytime the if statement is accessed, i could have a different set of these arrays for everytime the if statement is accessed, but php doesn't accept this and i wouldn't have a very good result, though if i can reach it i would be pleased.
But my goal is to get:
{
$array_forma_onda_fase1_afund_1[] = $row['L1_forma_tensao'];
$array_forma_onda_fase2_afund_1[] = $row['L2_forma_tensao'];
$array_forma_onda_fase3_afund_1[] = $row['L3_forma_tensao'];
}
{
$array_forma_onda_fase1_afund_2[] = $row['L1_forma_tensao'];
$array_forma_onda_fase2_afund_2[] = $row['L2_forma_tensao'];
$array_forma_onda_fase3_afund_2[] = $row['L3_forma_tensao'];
}
...
where the last number represents the array retrieved for the n-th time the if statement runned. Does someone have a tip for it?
Thanks in advance! Would appreciate any help.
EDIT
As asked, my real world terms is as follows:
I have a table from which i need to take all the data that is inside a given interval. BUT, there's a problem, my data is a sine function whose amplitude may change indefinite times (the data bank is entered by the user) and, when the amplitude goes inside that interval, i need to make some operations like getting the least value achieved while the data was inside that interval and some other parameters, for each interval separately, (That's why i created all those tables.) and count how many times it happpened.
So, in order to make one of the operations, i need an array with the data for each time the databank entered by the user goes in that interval (given by the limits of the create query.).
If i were not clear, just tell me please!
EDIT 2
Here's the image of part of the table i'm working with:
http://postimg.org/image/5vegnk043/
so, when the sine gets inside the interval i need, it can be seen by the L1_RMS column, who accuses it, so it's when i need to get the interval data until it gets outside the interval. But it may happens as many times as this table entered by the user brings it on and we need to bear in mind that i need all the intervals separately to deal with the data of each one.
Physics uh?
You can do what you wanted with the arrays, it's not pretty, but it's possible.
You can dynamically name your arrays with the _$a in the end, Variables variables, such as:
${"array_forma_onda_fase3_afund_" . $a}[] = "fisica é medo";
I can't figure out how to optimally do the following in PHP:
In a database, I have messages with a unique ID, like 19041985. Now, I want to refer to these messages in a short-url service but not using generated hashes but by simply 'calculate' the original ID.
In other words, for example: http://short.url/sYsn7 should let me calculate the message ID the visitor would like to request.
To make it more obvious, I wrote the following in PHP to generate these 'alphanumeric ID versions' and of course, the other way around will let me calculate the original message ID.
The question is: Is this the optimal way of doing this? I hardly think so, but can't think of anything else.
$alphanumString = '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ-_';
for($i=0;$i < strlen($alphanumString);$i++)
{
$alphanumArray[$i] = substr($alphanumString,$i,1);
}
$id = 19041985;
$out = '';
for($i=0;$i < strlen($id);$i++) {
if(isset($alphanumString["".substr($id,$i,2).""]) && strlen($alphanumString["".substr($id,$i,2).""]) > 0) {
$out.=$alphanumString["".substr($id,$i,2).""];
} else {
$out.=$alphanumString["".substr($id,$i,1).""];
$out.=$alphanumString["".substr($id,($i+1),1).""];
}
$i++;
}
print $out;
echo trim(base64_encode(pack("L", 19041987)), "=");
print_r(unpack("L", base64_decode("w44iAQ")));
Pack changes the number into four bytes, which is very short but unreadable.
Base64_encode changes the four bytes into some more human-readable characters.
It appends some = characters, which are not needed.
If you do base64_encode(19041987), you get the encoding for the string "19041987", which is not shorter.
You should never use a function inside a for statement since it's played during every loop.
For instance your
for($i=0;$i < strlen($alphanumString);$i++)
{
$alphanumArray[$i] = substr($alphanumString,$i,1);
}
should be
var $alphaLength = strlen($alphanumString);
for($i=0;$i < $alphaLength;$i++)
{
$alphanumArray[$i] = substr($alphanumString,$i,1);
}