I'm a junior PHP developer.
For a costumer I need to place some strings into a pdf. I'm using FPDI and I like it.
I have an existing template PDF and I need to insert every characters of a string into a little graphic box (see image).
Every characters must have 2 millimeters (8px approximately) from each others.
Every strings can have different length, so I thought do like this:
$name = 'namenamename';
$stringcount = strlen($name)-1;
$countspace = $stringcount*2;
//121 = coordinate of first box
for ($x=121; $x <= $x+$countspace; $x = $x+2) {
for ($i=0; $i <= $stringcount; $i++) {
$pdf->SetXY($x, 37);
$pdf->Write(0,$name[$i]);
}
}
That doesn't work. This is the error:
Maximum execution time of 30 seconds
Can you help me please with the correct approach and with good explanation for a newbie? :)
Try this code:
$name = 'namenamename';
$string_length = strlen($name);
$coordinate = 121; //Give to the variable coordinate the beginning value, in this case 121
for ($i=0; $i < $string_length; $i++){ //make only one loop for the string length so the loop ends when there is no more characters
$char = substr($name,$i,1); // this is "the tricky part", with substr you can grab each character with its position in the string
$pdf -> SetXY($coordinate, 37); // here you put the coordinate for the character
$pdf -> Write(0, $char); // write it
$coordinate += 2; // and increment it by two, since the character are two spaces away from each other
}
hope that will help..
Maybe not a great solution but you can modify the execution time with this line of code
set_time_limit ( $seconds );
Anyway give it a try but i think that is more an error in the logic of the loop maybe.
Can you say exactly the coordinate where you need the two first characters, the first is 121 + something or 121?
Related
I have this code:
$i = '0001';
$j = $i + 1;
I want to get 0002 but it give me only 2
How can I plus $i and keep that 000?
Thank you
Maybe this can give you an idea:
$i = '0001';
$i = intval($i);
$i++;
$a = '000';
$result = $a.$i;
echo $result;
The . between $a and $i is concatenating the variables into a string, keeping every character in them.
The code above will output 0002
Check it here: http://sandbox.onlinephpfunctions.com/code/fc2bd5861a6c0d937568b067e98e06977741019c
If you want to keep all leading zeroes, you could count them separately and increment it like this. Of course, this is something whipped out quickly and I'm 100% certain there are much better ways of doing this out there.
You can use str_pad to keep the leading zeroes.
Code here,
<?php
$i = '0001';
$val = $i + 1;
echo str_pad($val,4,"0",STR_PAD_LEFT); // 0001
?>
Click to learn more about str_pad
PHP took a useful feature from Perl: the ability to increment strings, using ++. Unfortunately, it didn't do it very well. If you increment "A0001", you get "A0002"; but if you increment "0001", you get 2 (as opposed to original Perl, which would give you "0002"). But, you can cheat:
$i="0001";
$j=":$a";
$j++;
$j=substr($j, 1);
This is more to both illustrate a cool thing not many people might be aware of, and how it was misimplemented, than to provide a real solution; I would definitely prefer to see a str_pad or sprintf solution in my code.
So i need to check if amount of chars from specific set in a string is higher than some number, what a fastest way to do that?
For example i have a long string "some text & some text & some text + a lot more + a lot more ... etc." and i need to check if there r more than 3 of next symbols: [&,.,+]. So when i encounter 4th occurrence of one of these chars i just need to return false, and stop the loop. So i think to create a simple function like that. But i wonder is there any native method in php to do such a thing? But i need some function which will not waste time parsing the string till the end, cuz the string may be pretty long. So i think regexp and functions like count_chars r not suited for that kind of job...
Any suggestions?
I don't know about a native method, I think count_chars is probably as close as you're going to get. However, rolling a custom solution would be relatively simple:
$str = 'your text here';
$chars = ['&', '.', '+'];
$count = [];
$length = strlen($str);
$limit = 3;
for ($i = 0; $i < $length; $i++) {
if (in_array($str[$i], $chars)) {
$count[$str[$i]] += 1;
if ($count[$str[$i]] > $limit) {
break;
}
}
}
Where the data is actually coming from might also make a difference. For example, if it's from a file then you could take advantage of fread's 2nd parameter to only read x number of bytes at a time within a while loop.
Finding the fastest way might be too broad of a question as PHP has a lot of string related functions; other solutions might use strstr, strpos, etc...
Not benchmarked the other solutions but http://php.net/manual/en/function.str-replace.php passing an array of options will be fast. There is an optional parameter which returns the count of replacements. Check that number
str_replace ( ['&','.','+'], '' , $subject , $count )
if ($count > $number ) {
Well, all my thoughts were wrong and my expectations were crushed by real tests. RegExp seems to work from 2 to 7 times faster (with different strings) than self-made function with simple symbol-checking loop.
The code:
// self-made function:
function chk_occurs($str,$chrs,$limit){
$r=false;
$count = 0;
$length = strlen($str);
for($i=0; $i<$length; $i++){
if(in_array($str[$i], $chrs)){
$count++;
if($count>$limit){
$r=true;
break;
}
}
}
return $r;
}
// RegExp i've used for tests:
preg_match('/([&\\.\\+]|[&\\.\\+][^&\\.\\+]+?){3,}?/',$str);
Of course it works faster because it's a single call to native function, but even same code wrapped into function works from 2 to ~4.8 times faster.
//RegExp wrapped into the function:
function chk_occurs_preg($str,$chrs,$limit){
$chrs=preg_quote($chrs);
return preg_match('/(['.$chrs.']|['.$chrs.'][^'.$chrs.']+?){'.$limit.',}?/',$str);
}
P.S. i wasn't bothered to check cpu-time, just was testing walltime measured via microtime(true); of the 200k iteration loop, but it's enough for me.
I'm trying to use CodeIgniter to write up a small program for school which generates a random 'key' every time I click the 'generate' button. Looking to see if there's a way for me to create a function where I can fill up a 14 character array with a random number or letter and then set the array to a variable which I can call upon to display as my generated key.
Any and all help would be much appreciated as I am new to CodeIgniter.
A while back I wrote this function in PHP, it does what it does and gives you some flexibility as well through complexity modifiers, I used a default set of 5 different 'levels' of characters and the length is also variable ofcourse.
I'm just going to chuck it in here and 'try' to explain what is going on as well as I can by comments:
function rsg($length = 10, $complexity = 2) {
//available 'complexity' subsets of characters
$charSubSets = array(
'abcdefghijklmnopqrstuvwxyz',
'ABCDEFGHIJKLMNOPQRSTUVWXYZ',
'0123456789',
'!##$%^&*()_+{}|:">?<[]\\\';,.`~',
'µñ©æáßðøäåé®þüúíóö'
);
// will be filled with subsets from above $charSubsets
$chars = '';
//concact each subset until complexity is reached onto the $chars variable
for ($i = 0; $i < $complexity; $i++)
$chars .= $charSubSets[$i];
//create array containing a single char per entry from the combined subset in the $chars variable.
$chars = str_split($chars);
//define length of array for mt_rand limit
$charCount = (count($chars) - 1);
//create string to return
$string = '';
//idk why I used a while but it won't really hurt you when the string is less than 100000 chars long ;)
$i = 0;
while ($i < $length) {
$randomNumber = mt_rand(0, $charCount); //generate number within array index range
$string .= $chars[$randomNumber]; //get that character out of the array
$i++; //increment counter
}
return $string; //return string created from random characters
}
This is what I currently use and it has satisfied my needs for quite some time now, if anyone reading over this has improvements I'd love to hear them as well!
$a=array(rand(10000000000000, 99999999999999));
is a quick way to get a 14 digit array.
It depends on how random you want it to be. You could specify all characters you want in a $characters string, then just create a string up to $length, picking a random substring of length 1 from the characters string.
What are the requirements?
Do you want it to be as random as possible (This link might be useful)
Are multiple occurrences of one character allowed in one random string?
Here's an example though: PHP random string generator
I'm generating a 6 digit code from the following characters. These will be used to stamp on stickers.
They will be generated in batches of 10k or less (before printing) and I don't envisage there will ever be more than 1-2 million total (probably much less).
After I generate the batches of codes, I'll check the MySQL database of existing codes to ensure there are no duplicates.
// exclude problem chars: B8G6I1l0OQDS5Z2
$characters = 'ACEFHJKMNPRTUVWXY4937';
$string = '';
for ($i = 0; $i < 6; $i++) {
$string .= $characters[rand(0, strlen($characters) - 1)];
}
return $string;
Is this a solid approach to generating the code?
How many possible permutations would there be? (6 Digit code from pool of 21 characters). Sorry math isn't my strong point
21^6 = 85766121 possibilities.
Using a DB and storing used values is bad. If you want to fake randomness you can use the following:
Reduce to 19 possible numbers and make use of the fact that groups of order p^k where p is an odd prime are always cyclic.
Take the group of order 7^19, using a generator co-prime to 7^19 (I'll pick 13^11, you can choose anything not divisible by 7).
Then the following works:
$previous = 0;
function generator($previous)
{
$generator = pow(13,11);
$modulus = pow(7,19); //int might be too small
$possibleChars = "ACEFHJKMNPRTUVWXY49";
$previous = ($previous + $generator) % $modulus;
$output='';
$temp = $previous;
for($i = 0; $i < 6; $i++) {
$output += $possibleChars[$temp % 19];
$temp = $temp / 19;
}
return $output;
}
It will cycle through all possible values and look a little random unless they go digging. An even safer alternative would be multiplicative groups but I forget my math already :(
There is a lot of possible combination with or without repetition so your logic would be sufficient
Collision would be frequent because you are using rand see str_shuffle and randomness.
Change rand to mt_rand
Use fast storage like memcached or redis not MySQL when checking
Total Possibility
21 ^ 6 = 85,766,121
85,766,121 should be ok , To add database to this generation try:
Example
$prifix = "stamp.";
$cache = new Memcache();
$cache->addserver("127.0.0.1");
$stamp = myRand(6);
while($cache->get($prifix . $stamp)) {
$stamp = myRand(6);
}
echo $stamp;
Function Used
function myRand($no, $str = "", $chr = 'ACEFHJKMNPRTUVWXY4937') {
$length = strlen($chr);
while($no --) {
$str .= $chr{mt_rand(0, $length- 1)};
}
return $str;
}
as Baba said generating a string on the fly will result in tons of collisions. the closer you will go to 80 millions already generated ones the harder it will became to get an available string
another solution could be to generate all possible combinations once, and store each of them in the database already, with some boolean column field that marks if a row/token is already used or not
then to get one of them
SELECT * FROM tokens WHERE tokenIsUsed = 0 ORDER BY RAND() LIMIT 0,1
and then mark it as already used
UPDATE tokens SET tokenIsUsed = 1 WHERE token = ...
You would have 21 ^ 6 codes = 85 766 121 ~ 85.8 million codes!
To generate them all (which would take some time), look at the selected answer to this question: algorithm that will take numbers or words and find all possible combinations.
I had the same problem, and I found very impressive open source solution:
http://www.hashids.org/php/
You can take and use it, also it's worth it to look in it's source code to understand what's happening under the hood.
Or... you can encode username+datetime in md5 and save to database, this for sure will generate an unique code ;)
I have been reading/testing examples since last night, but the cows never came home.
I have a file with (for example) approx. 1000 characters in one line and want to split it into 10 equal parts then write back to the file.
Goal:
1. Open the file in question and read its content
2. Count up to 100 characters for example, then put a line break
3. Count 100 again and another line break, and so on till it's done.
4. Write/overwrite the file with the new split content
For example:
I want to turn this => KNMT2zSOMs4j4vXsBlb7uCjrGxgXpr
Into this:
KNMT2zSOMs
4j4vXsBlb7
uCjrGxgXpr
This is what I have so far:
<?php
$MyString = fopen('file.txt', "r");
$MyNewString;
$n = 100; // How many you want before seperation
$MyNewString = substr($MyString,0,$n);
$i = $n;
while ($i < strlen($MyString)) {
$MyNewString .= "\n"; // Seperator Character
$MyNewString .= substr($MyString,$i,$n);
$i = $i + $n;
}
file_put_contents($MyString, $MyNewString);
fclose($MyString);
?>
But that is not working quite the way I anticipated.
I realize that there are other similiar questions like mine, but they were not showing how to read a file, then write back to it.
<?php
$str = "aonoeincoieacaonoeincoieacaonoeincoieacaonoeincoieacaonoeincoieacaon";
$pieces = 10;
$ch = chunk_split($str, $pieces);
$piece = explode("\n", $ch);
foreach($piece as $line) {
// write to file
}
?>
http://php.net/manual/en/function.chunk-split.php
Hold on here. You're not giving a file name/path to file_put_contents();, you're giving a file handle.
Try this:
file_put_contents("newFileWithText.txt", $MyNewString);
You see, when doing $var=fopen();, you're giving $var a value of a handle, which is not meant to be used with file_put_contents(); as it doesnt ask for a handle, but a filename instead. So, it should be: file_put_contents("myfilenamehere.txt", "the data i want in my file here...");
Simple.
Take a look at the documentation for str_split. It will take a string and split it into chunks based on length, storing each chunk at a separate index in an array that it returns. You can then iterate over the array adding a line break after each index.