Using samples() with php-ml

Question

I am using php-ml and taking in a .csv file with 6 columns and thousands of lines, i want every 5th element (column) of each array to be saved in $samples. I have tried the following which gives me the first element of each array.

$dataset = new CsvDataset('myCsvFile.csv', 1);

$samples = [];
foreach ($dataset->getSamples() as $sample) {
    $samples[] = $sample[0];
}

However this gives me the first element of each array, if i change the $sample[0] to $sample[4] as i thought syntactically this would work i get an Undefined offset on the line in question. I am new to PHP and don't understand why this would happen.

If the code is left as above and printed out it looks like the following:

    Array
(
    [0] => 1157
    [1] => 1157
    [2] => 1157
    [3] => 1157
    [4] => 1157
    [5] => 1157
    [6] => 1157
    [7] => 1157
    [8] => 1157

...and so on.

What have you tried so far? Stack Overflow isn't a code writing service... — Tom Udding, Apr 28 '17 at 15:24
@johnfish92 the '0' (`$sample[0];`) selects the first column of your CSV file. '1' will select the second column, '2' will select the third column and so on... — Tom Udding, Apr 28 '17 at 15:37
I added your previous code back since you just removed code and replaced it with totally different code. Maybe you should post what you're actually using. — AbraCadaver, Apr 28 '17 at 15:39
@TomUdding I had tried that however it gave me an error message 'undefined offset' therefore i thought it was incorrect syntax with php. Do you know why it throws that error if syntacitcally its correct? Note: it throws this error on that exact line as well. — johnfish92, Apr 28 '17 at 15:40
@AbraCadaver i have edited the question as leaving the body of code in is getting answers which are not what i need and wasting users time. — johnfish92, Apr 28 '17 at 16:05

Ajeet Kumar · Answer 1 · 2017-04-28T15:38:27.390

0

You can try this

$csv = array();
$csvNewArray = array();
$lines = file('myCsvFile.csv', FILE_IGNORE_NEW_LINES);
foreach ($lines as $key => $value)
{
    $csv[$key] = str_getcsv($value);
    if(isset($csv[$key][4])){
     $csvNewArray[$key] = $csv[$key][4];
    }
}

edited Apr 28 '17 at 15:38

answered Apr 28 '17 at 15:28

Ajeet Kumar

805
1
7
26

Why are you storing into `$csv[$key][6]`? He said he wants to store the fifth element into a new array. – Barmar Apr 28 '17 at 15:33
because array has start with 0th element – Ajeet Kumar Apr 28 '17 at 15:34
Why are you assigning into the same array at all? – Barmar Apr 28 '17 at 15:37
because there is thousands of lines if we made multiple loops than its take too much time. so i have updated my answer to get 5th element in new array – Ajeet Kumar Apr 28 '17 at 15:39
You don't need multiple loops. Just `$new_array[] = $csv[$key][4]` – Barmar Apr 28 '17 at 15:43
yes i have also done this. Put the value in new Array Element [UPDATED]. Thanks for notice that – Ajeet Kumar Apr 28 '17 at 15:45

Barmar · Answer 2 · 2017-04-28T15:53:51.937

0

Use fgetcsv() to read from the file, then access the appropriate element of these arrays to get the fifth item of each row.

$fh = fopen("myCsvFile.csv", "r") or die("Can't open CSV file\n");
$csv = array();
$sample = array();
while ($row = fgetcsv($fh)) {
    $csv[] = $row;
    $sample[] = $row[4];
}
fclose($fh);

edited Apr 28 '17 at 15:53

answered Apr 28 '17 at 15:47

Barmar

741,623
53
500
612

You need to make here array for multiple **$sample[] = $row[4];** – Ajeet Kumar Apr 28 '17 at 15:50

Using samples() with php-ml

2 Answers2