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I tried to make a simple name generator. Help me to identify why it's not working. I think it's because of mt_rand function. Sorry if question seems banal or irrelevant, I'm first time here and new to programming. Here's the code:
<?php
echo 'Ovo je moja verzija Polumenta generatora';
$prvo = 'bcdfghtnjpknmlrjdzdjs';
$drugo = 'aeiou';
$trece = 'bcdfghtnjpknmlrjsdzdj';
$cetvrto = 'uo';
$prvos = mt_rand($prvo[0],$prvo[17]);
$drugos = mt_rand($drugo[0],$drugo[4]);
$treces = mt_rand($trece[0],$trece[17]);
$cetvrtos = mt_rand($cetvrto[0],$cetvrto[1]);
echo $prvos.$drugos.$treces.$cetvrtos.' Polumenta'
?>
mt_rand takes integers as arguments and returns an integer. You are trying to pass it characters and return characters. You should do something like:
<?php
echo 'Ovo je moja verzija Polumenta generatora';
$prvo = 'bcdfghtnjpknmlrjdzdjs';
$drugo = 'aeiou';
$trece = 'bcdfghtnjpknmlrjsdzdj';
$cetvrto = 'uo';
$prvos = $prvo[mt_rand(0,strlen($prvo) - 1)];
$drugos = $drugo[mt_rand(0,strlen($drugo) - 1)];
$treces = $trece[mt_rand(0,strlen($trece) - 1)];
$cetvrtos = $cetvrto[mt_rand(0,strlen($cetvrto) - 1)];
echo $prvos.$drugos.$treces.$cetvrtos.' Polumenta'
?>
You can make it in another way, using arrays and rand() function.
$chrs[0] = str_split('bcdfghtnjpknmlrjdzdjs'); // array of consonants
$chrs[1] = str_split('aeiou'); // array of vowels
$length = 8; // nick name length
Than generate random sequence of chars any length
for($i = 0; $i < $length; $i++)
{
$v_or_c = rand(0,1);
if($v_or_c)
{
$nick_name .= $chrs[$v_or_c][rand(0, sizeof($chrs[$v_or_c]))];
}
else
{
$nick_name .= $chrs[$v_or_c][rand(0, sizeof($chrs[$v_or_c]))];
}
}
echo ucfirst($nick_name); // ucfirst - to upper case first letter
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function standard_deviation_population ($a)
{
//variable and initializations
$the_standard_deviation = 0.0;
$the_variance = 0.0;
$the_mean = 0.0;
$the_array_sum = array_sum($a); //sum the elements
$number_elements = count($a); //count the number of elements
//calculate the mean
$the_mean = $the_array_sum / $number_elements;
//calculate the variance
for ($i = 0; $i < $number_elements; $i++)
{
//sum the array
$the_variance = $the_variance + ($a[$i] - $the_mean) * ($a[$i] - $the_mean);
}
$the_variance = $the_variance / $number_elements;
//calculate the standard deviation
$the_standard_deviation = pow( $the_variance, 0.5);
//return the variance
return $the_standard_deviation;
}
$query_question = mysqli_query($con,"SELECT * FROM question order by s_id");
$QuestionDimArray = array();
while ($data_question = mysqli_fetch_array($query_question))
{
$QuestionDimArray []= $data_question['q_id'];
}
$a = array($QuestionDimArray());
$standard_deviation = standard_deviation_population ($a);
echo "standard_deviation =" .$standard_deviation;
How to store database value into
$variable = array([database values here]);
for example, with defined values (1,2,3)
$a = array(1,2,3);
$standard_deviation = standard_deviation_population ($a);
echo "standard_deviation =" .$standard_deviation;
that returns,
standard_deviation = 0.81649658092773
It is not good idea to calculate the standard deviation this way. Database systems has a built-in functions for standard deviation. You can get it in one query, something like this: SELECT STDDEV_POP(q_id) FROM question.
In your code the $QuestionDimArray is already an array. You could just $standard_deviation = standard_deviation_population ($QuestionDimArray);
Your question is not clear but if I understand well you want put all your database result in $variable ?
$query_question = mysqli_query($con,"SELECT * FROM question order by s_id");
$QuestionDimArray = array();
while ($data_question = mysqli_fetch_array($query_question)) {
$QuestionDimArray []= $data_question['q_id'];
/* if you want the full data line from your query use. It depends your implementation.
You will have an 2d array
[['col1' => 'val_line_1_1', 'col2'=> 'val_line_1_2',...],...,['col1' => 'val_line_n_1', 'col2'=> 'val_line_n_2',...]]
$QuestionDimArray []= $data_question;
*/
}
// $a = array($QuestionDimArray()); unless you want copy the array this line is useless. Event worst its wrong
$standard_deviation = standard_deviation_population ($questionDimArray);
echo "standard_deviation =" .$standard_deviation;
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Im trying to display 2 or more unique random results from a text file, How do I do that please?
But I need unique results and not 2 or more of the same.
Currently using this code, but it only returns 1 random result:
<?php
$text = file_get_contents('flatFileDB.txt');
$textArray = explode("\n", $text);
$randArrayIndexNum = array_rand($textArray);
$randPhrase = $textArray[$randArrayIndexNum];
?>
<?php echo $randPhrase ?>
I would use something like that
shuffle($textArray);
echo $textArray[0];
echo $textArray[1];
http://php.net/manual/tr/function.shuffle.php
You can give a shot to this also. Code is not tested. I am collecting the used into an array, and check, is that used before.
$text = file_get_contents('flatFileDB.txt');
$textArray = explode("\n", $text);
$used = array();
$countOfRandoms = 2;
$randoms = array();
$i = 1;
do {
if ($countOfRandoms == $i) {
break;
}
$randArrayIndexNum = array_rand($textArray);
if (in_array($randArrayIndexNum, $used)) {
continue;
}
$used[] = $randArrayIndexNum;
$random = $textArray[$randArrayIndexNum];
$i++;
} while (true);
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I think the subject hits it better than I was expecting.
I need a function which returns random numbers which result in a given value (X) when they are summed up.
Something like this:
getRandomTo(10); // result for example: array(2,3,5)
getRandomTo(10); // result for example: array(4,3,3)
getRandomTo(12); // result for example: array(5,1,6)
I could not find a generic algorithm function for solving that requirement. Further more I cannot imagine a FAST and performant way to create something like this my self.
Please help me out
function getRandomTo($num)
{
$x = Array();
$i = 0;
do
{
$x[$i] = rand(1,$num);
$num = $num - $x[$i];
$i++;
}while($num > 0);
print_r($x);
}
Maybe do this:
create a random value between 0 and X; say this one is called r1. save this in your array.
create another random value between 0 and (X-r1), name it r2. save it also.
do these steps as often as you need it (or as long as r1+...+rn is lower than X)
Another solution:
function randomTo($numIn) {
$numOut = 0;
$numbers = array();
do {
$add = rand(1, $numIn);
if($numOut + $add > $numIn)
continue;
$numOut += $add;
$numbers[] = $add;
} while( $numOut != $numIn );
return $numbers;
}
$result = randomTo(15);
var_dump($result);
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Suppose I have a string such as this:
ABC.DEF.GHI.JKL (This string could have any length and amount of characters between dots)
I want to add the following combinations into an array.
ABC
ABC.DEF
ABC.DEF.GHI
ABC.DEF.GHI.JKL
So basically the string should be split with the dot character and then the individual sub-strings should be combined.
I have a function already, but in my opinion this seems too complicated to achieve the result.
$myarray = array();
$split = explode('.', 'that.string.with.dots');
$string = '';
for ($i = 0; $i < count($split); $i++) {
$string .= $split[$i];
myarray[] = $string;
$string .= '.';
}
Any suggestions on improving this?
Thanks
Michael
Perhaps this:
$split = explode('.', 'that.string.with.dots');
for ($i = 1; $i < count($split); $i++) {
$split[i] = $split[$i-1] . '.' . $split[i];
}
It just concats the current with the previous.
I have the feeling that you are asking if there is a PHP function that will achieve this result with a single function call, but I don't think there is one.
You can rewrite the code as pritaeas did in his answer, to remove two lines of code, but it will still be the same concept.
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Closed 11 years ago.
Possible Duplicate:
PHP: How to generate a random, unique, alphanumeric string?
i want to generate random token [alphanumeric] for random length [between 4-6] characters.
Can anyone help ?
You could use uniqid (search for "token" in the examples given there) and shorten it with substr.
Firstly, you can just get a random number between 10+26+26=62 6 times, and then calculate the resulted string, this seems easy enough.
<?php
function ()
{
$letters={a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,u,v,w,x,y,z,0,1,2,3,4,5,6,7,8,9,10}
return array_rand($letters).array_rand($letters)......... // you get the point
?>
or if you prefer the 'hard' way...
$len = random(4,6);
$token = array();
for ($i = 0; $i < $len; $i++) {
$ord = 0;
switch(random(1,3)) {
case 1: // 0 - 9
$ord = random(48,57);
break;
case 2: // A - Z
$ord = random(65,90);
break;
case 3: // a - z
$ord = random(97,112);
break;
}
$token[] = chr($ord);
}