Count number of columns in a CSV file, using PHP? - php

Question

Is it possible to validate a text file before I dump its data into a MYSQL database?
I want to check if it contains, say, 5 columns (of data). If so, then i go ahead with the following query:
LOAD DATA CONCURRENT INFILE 'c:/test/test.txt'
INTO TABLE DUMP_TABLE FIELDS TERMINATED BY '\t' ENCLOSED BY '' LINES TERMINATED BY '\n' ignore 1 lines.
If not, I remove the entire row. I repeat this process for all rows in the txt file.
The text file contains data of the format:
id col2 col3 2012-07-27-19:27:06 col5
id col2 col3 2012-07-25-09:58:50 col5
id col2 col3 2012-07-23-10:14:13 col5

Answer 1

EDIT: After reading your comments, here's the code for doing the same on tab separated data:
$handler = fopen("myfile.txt","r");
$error = false;
while (!feof($handler)){
fgets($handler,$linetocheck);
$cols = explode (chr(9), $linetocheck); //edit: using http://es.php.net/manual/en/function.fgetcsv.php you can get the same result as with fgets+explode
if (count($cols)>$max_cols){
$error=true;
break;
}
}
fclose($handler);
if (!$error){
//...do stuff
}
This code reads a file, let's say "myfile.txt", line by line, and sets variable $error to true if any of the lines has a length of more than $max_cols. (My apologies if that's not what you're asking, your question is not the most clear to me)
$handler = fopen("myfile.txt","r");
$error = false;
while (!feof($handler)){
fgets($handler,$linetocheck);
if (strlen($linetocheck)>$max_cols){
$error=true;
break;
}
}
fclose($handler);
if (!$error){
//...do stuff
}

Answer 2

I know it's an old thread, but I was looking something similar for myself and I came across to this topic, but none of the answers provided here helped me.
Thus, I've went ahead and came with my own solution which is tested and works perfectly (can be improved).
Assume, we have a CSV file named example.csv that contains the following dummy data (on purpose, the last line, 6th, contains one extra data then the other rows):
Name,Country,Age
John,Ireland,18
Ted,USA,22
Lisa,UK,23
Michael,USA,20
Louise,Ireland,22,11
Now, when we're checking the CSV file to assure all the rows have the same number of data, the following block of code will do the trick and pin-point on what line the error occurred:
function validateCsvColumnLength($pathToCsvFile)
{
if(!file_exists($pathToCsvFile) || !is_readable($pathToCsvFile)){
throw new \Exception('Filename doesn`t exist or is not readable.');
}
if (!$handle = fopen($pathToCsvFile, "r")) {
throw new \Exception("Stream error");
}
$rowLength = [];
$rowNumber = 0;
while (($data = fgetcsv($handle)) !== FALSE) {
$rowLength[] = count($data);
$rowNumber++;
}
fclose($handle);
$rowKeyWithError = array_search(max($rowLength), $rowLength);
$differentRowCount = count(array_unique($rowLength));
// if there's a row that has more or less data, throw an error with the line that triggered it
if ($differentRowCount !== 1) {
throw new \Exception("Error, data count from row {$rowKeyWithError} does not match header size");
}
return true;
}
To actually test it, just do a var_dump() to see the result:
var_dump(validateCsvColumnLength('example.csv'));

Answer 3

What columns do you mean? If you just means amount of characters in rows, just split (explode) the file into many rows and check whether their lengths are equal to 5.
If you meant columns with delimeters, then you should find amount of occurences of that splitter in each row and then again check are they equal to 5. use fgetcsv for that

Answer 4

I'm assuming your talking about the length of each line in the file. If so, here's a possible solution.
$file_handle = fopen("myfile", "r");
while (!feof($file_handle)) {
$line = fgets($file_handle);
if(strlen($line)!=5) {
throw new Exception("Could not save file to database.");
break;
}
}
fclose($file_handle);

Answer 5

Yes, it is possible. I've done that exact thing. Use PHP's csv processing functions.
You will need these functions:
fopen()
fgetcsv()
And possibly some others.
fgetcsv returns an array.
I'll give you a short example of how you can validate.
here's the csv:
col1,col2,col3,col4
1,2,3,4
1,2,3,4,
1,2,3,4,5
1,2,3,4
I'll skip the fopen part and go straight to the validation step.
Note that "\t" is the tab character.
$row_length;
$i = 0;
while($row = fgetcsv($handle,0,"\t") {
if($i == 0) {
$row_length = sizeof($row);
} else {
if(sizeof($row) != $row_length) {
echo "Error, line $i of the data does not match header size";
break;
}
}
}
That would test each row to make sure it is the same as the 1st row's ($i = 0) length.
EDIT:
And, in case you don't know how to search the internet, here is the page for fgetcsv:
http://php.net/manual/en/function.fgetcsv.php
Here is the function prototype:
array fgetcsv ( resource $handle [, int $length = 0 [, string $delimiter = ',' [, string $enclosure = '"' [, string $escape = '\' ]]]] )
As you can see, it has everything you would need for doing a quick scan in PHP before you send your data to LOAD DATA IN FILE.
I have solved your exact problem in my own program. My program also automatically eliminates duplicate rows and other cool stuff.

Answer 6

You can try to see if fgetcsv will suffice. If it doesn't, please be a bit more descriptive on what you mean by columns.