Newline in File() read

jimburns1

Let me admit right up front this is my first foray into php. I'm trying to simply use a small data file to populate a page. I'm using the file() function but I want my "data records" to be seperated by a double \n.

My problem is I can't seem to compare a line to anything. My first problem was determining the end of a data block, finding the double newline. But in frustration, I just tried to compare a line to a known value and I still can't compare strings correctly.

Here's a sample data file,

N2325N
Piper Tomahawk

N2378K
Piper Tomahawk

N11242
Cessna 150

N68440
Cessna 152

btw, I even tried '*' chars between lines and couldn't match them correctly.

Here's what I'm trying to do,

function getNextDataBlock() {
global $data;
$blk = array();

$line = array_shift($data);
while ($line <> "") { 
  array_push($blk, $line);
  $line = array_shift($data);
}

return $blk;

}

$dataBlock = getNextDataBlock();
echo $dataBlock;

In theory, $data from the file() read is an array. I'm simply trying to build a return array of the first data block, stopping on the next blankline, and leaving the remaining items on $data. (Yes, I'm already thinking I just need to find the next newline and split the array. I'm not familiar with all php's built in functions and this one became apparent first. I still can't seem to find the empty line... or ANYTHING for that matter.

I've used print_r() to look at the data array and it's what I expect. However even for known values, say I expect $data[3] to equal "N2378K", if I try to match that it always fails.

Here's what it's become,

function getNextDataBlock() {
global $data;
$blk = array();
//echo "<br />data ==>"; print_r($data);
//echo "<br />blk ==>"; print_r($blk);

$line = array_shift($data);
while ($line <> "") { 
  echo "<br />+$line";
  // All these line NEVER hit!
  //if ($line == "") print("nothing");
  //if ($line == " ") print("space");
  //if ($line == "*") print("star");
  //if ($line == "N2378K") print("tailnumber");

  // All these lines ALWAYS hit.  ??
  if (strcmp($line, "") == 0) print("nothing");
  if (strcmp($line, " ") == 0) print("space");
  if (strcmp($line, "*") == 0) print("star");
  if (strcmp($line, "N2378K") == 0) print("tailnumber");
  if (strcmp($line, "N2378K\n") == 0) print("tailnumber spc");

  array_push($blk, $line);
  //echo "<br />blk ==>"; print_r($blk);

  $line = array_shift($data);
  rtrim($line);
  echo "<br /><br />getting new line ==> [$line]";
}

//echo '<br />looking in blk ==>'; print_r($blk);
return $blk;

}

//$data[3] = "";
$dataBlock = getNextDataBlock();
echo $dataBlock;

Thanks for any help. I'm open to completely new ideas on how to read in this small data file and strip off one block of data at a time into it's own small $blk array. But I'd also like to understand why I can't match anything! I've tried everything, comparing for "\n", x32 actually show up on the web page so I tried searching for a space, nothing. I can't kill the loop on an empty line.

Many thanks,

/jim

jimburns1

Ok, just a bit more on this.... New method...

Just looking for the index of the next empty line in the data array. I tested this method first with a hard-coded data array then went back to the file() read and it broke! I just don't understand the format of the empty line coming from the file read.

Here's the function,

<?php
function getNextDataBlockEndIndex() {
global $data;
echo "<br />data ==>", print_r($data), "<<br />";
//$stopmark = "";
//$stopmark = "\r";
$stopmark = "* ";

$i = 0;
do {
  $line = $data[$i++];
  echo "<br />$line";
} while ($line <> $stopmark);
return $i;

}

echo ("calling...<br />");
$idx = getNextDataBlockEndIndex();
echo ("<br />$idx was returned");

and previous to this,

<?php
$file = 'fleet.tdb';
$data = file($file) or die('Could not read file!');
//$data = array('N2325N', 'Piper Tomahawk', '', 'N2378K', 'Piper Tomahawk', '', 'N11242', 'Cessna 150', '');
//$data = array('N2325N', 'Piper Tomahawk', '', 'N2378K', 'Piper Tomahawk', '', 'N11242', 'Cessna 150', '*');
?>

By using $stopmark I can change the target match pattern a little easier without changing the loop code. Again, if I use my hard-coded array it works fine, but not using the file() array.

What am I missing?

Many thanks,

laserlight

Observe the indices of the lines that contain data in the array returned by file():
0,1
3,4
6,7
9,10

The solution to place each entry in a single array element while using file() is then trivial:

$rawdata = file($filename);
$size = count(rawdata);
$contents = array();
for ($i = 0; $i < $size; $i += 3) {
	$contents[] = $rawdata[$i] . $rawdata[$i+1];
}

Note that the newline sequences remain, if you dont want them, you have to [man]rtrim/man them.

jimburns1

Yes, that might work, thanks.

I prefer to write code that doesn't need to be changed when the input data changes.

What I need then is to actually determine when I've read in an empty line. I can print_r() the array and I can see the "empty" indices, but I can't tell what's in them in such as way as I can construct a comparison that will work. Everytime I hard code an empty line indicator I can get a positive comparison, there's something about reading in the line with file(), maybe the end of line character that I don't understand. I've tried \n, \r, I've tried looking at the resulting web page but IT actually displays a x32, a space... And please take note in my first example, I am rtrim()-ing the next data line, but it has no effect on my ability to build a comparison. For example, I know one of the tail numbers is "N2378K" yet even with an rtrim() I can't get a comparison of $line and a hard-coded "N2378K" that will match successfully.

Anyway, I'm not one to dis someone for trying to help, especially since I'm chasing my backside on this one... but please at least address my question in all this.

Regards,

laserlight

What I need then is to actually determine when I've read in an empty line.

If an element of an array returned by file() is a blank line, then it will be equal to "\n", "\r" or "\r\n", depending on your platform (usually \n will do).

In my example, however, I take advantage of the way the array indices will be constructed to simply skip over the blank lines. However, I think the array I constructed isnt the one you want. You could try this:

$rawdata = file($filename);
$size = count(rawdata);
$contents = array();
for ($i = 0; $i < $size; $i++) {
	$temp = rtrim($rawdata[$i]);
	if (strlen($temp) > 0) {
		$contents[] = $temp;
	}
}

The idea is to rtrim() each line, then check that the length is not zero.
If so, we insert it into the array.
Consequently, you have an array of non-null lines that have the ending newline sequence stripped off.
As such, you can compare to strings like "N2378K" without a problem.

but I can't tell what's in them in such as way as I can construct a comparison that will work

Print to file, view in a hex editor.

jimburns1

If an element of an array returned by file() is a blank line, then it will be equal to "\n", "\r" or "\r\n", depending on your platform (usually \n will do).

I finally found that "\r\n" was the correct end of line sequence. The trouble however, is that even if I rtrim() the line, I still need to use this as the indicator. Does that mean that rtrim() isn't properly removing them or am I missing something? I don't know but I'm up and running so for now that's water under the bridge.

Just to summarize what I ended up with

$page = array();
$file = 'fleet.tdb';
$data = file($file) or die('Could not read file!');
$blk = array();

function getNextDataBlockEndIndex() {
global $data;
$stopmark = "\r\n";

$i = -1;
do {
  if (++$i < count($data)) $line = $data[$i];
  //rtrim($line);  // makes no difference
} while (($i < count($data)) AND (!(strcmp($line, $stopmark) == 0)));
return $i;

}

function getNextDataBlock() {
global $blk;
global $data;

$idx = getNextDataBlockEndIndex();
$blk = array_slice($data, 0, $idx);
reset($data);
$data = array_slice($data, $idx+1);

}

function getNextPlaneBlock() {
global $blk;
getNextDataBlock();
if (! empty($blk)) {
echo "<div class=\"ad_note\">";
echo "<div class=\"fleet_tn\"><a target=\"pic_view\" href=\"images/fleet/$blk[1]\">
<img src=\"images/fleet/$blk[2]\" border=\"0\" alt=\"thumbnail\" /></a></div>";
echo "<p class=\"fleet_text\" />";
echo "$blk[3], $blk[0]<br />$blk[4]<br />$blk[5]<br />$blk[6]<br />$blk[7]<br />";
echo "<br /> ";
echo "</div>";
return 1;
} else return 0;
}

Then later within the body of the document all I need is,

    <!-- Fleet box -->
    <center> 
      <div class="fleet_box">         

        <!-- Plane  -->  
        <?php do ; while (getNextPlaneBlock() == 1);?>

      </div>
    </center>

And I have a completely dynamic listing of the entire fleet managed by a simple text file with no further intervention required.

Now, I do have a slightly expanded data file... but more importantly easily expanded and if new data needs to be added I don't have to play any games of recounting skipped indices and I simply adjust the use of the $blk[x] elements in the output function getNextPlaneBlock(), one time only.

N2325N
f01_n2325n.jpg
tn_f01_n2325n.jpg
Piper Tomahawk
2-seater, 110 hp
data 3
data 4
$54 / hr (Wet)

N2378K
f02_n2378k.jpg
tn_f02_n2378k.jpg
Piper Tomahawk
2-seater, 110 hp
data 3
data 4
$54 / hr (Wet)

N11242
f10_n11242.jpg
tn_f10_n11242.jpg
Cessna 150
2-seater, 100 hp
data 3
data 4
$54 / hr (Wet)

I've been out of college and writing software for 15ys but this is my first foray into php. If anyone has any ideas or comments on something I've done wrong, inefficiently or how to simply make the method better, I'm ALL ears. Thanks for the input...

/jim/houston/tx

laserlight

You're not using rtrim() correctly.
You should use:
$str = rtrim($str);

jimburns1

D'oh.... roger that.... thanks