Unexpected Behavior when Parsing Text File - php

Question

I am learning PHP, & right now I'm stuck.
I am reading a .txt file in the script. The file contents are like this:
joe:secret
root:admin
I can read the file easily using the file() function, which returns an array. I store the data in a a variable as:
$data = file('location/file.txt');
Next I use foreach loop, and then I explode each line, and store its contents in a variable again. Then I put checks on the variable, but this is where I get behavior which I don't understand.
foreach ($data as $d) {
$row = explode(":", $d);
if ($row[0] == "joe" && $row[1] == "secret") {
echo "match found ";
}
}
The above code does give expected output. Why is that? If I do this,
echo $row[0]; echo $row[1];
then I do receive correct output. So I don't get why my check fails?

Answer 1

This one was tricky; I don't blame you for not catching this :)
So first, let's investigate with the php -a interactive shell:
php > $data = file('test.txt');
php > var_dump($data);
array(3) {
[0]=>
string(11) "joe:secret
"
[1]=>
string(11) "root:admin
"
[2]=>
string(1) "
"
}
See how the closing quote is on a separate line? That's because the \n's at the end of each line are kept inside each array element in $data. So $row[1] doesn't equal "secret"; it equals "secret\n". To fix this, all we need is rtrim():
foreach ($data as $line) {
$line = rtrim($line);
$row = explode(":", $line);
if ($row[0] == "joe" && $row[1] == "secret") {
echo "Match found for joe!";
}
}
Now, it works as expected:
php > $data = file('test.txt');
php > foreach ($data as $line) {
php { $line = rtrim($line);
php { $row = explode(":", $line);
php {
php { if ($row[0] == "joe" && $row[1] == "secret") {
php { echo "Match found for joe!";
php { }
php { }
Match found for joe!
php >
Edit: We could also use file_get_contents() instead of file(), so we just get the file contents as a string, and convert it into an array ourselves:
$data = file_get_contents('test.txt');
foreach (explode("\n", $data) as $line) {
$row = explode(":", $line);
if ($row[0] == "joe" && $row[1] == "secret") {
echo "Match found for joe!";
}
}