On 6/14/2011 10:35 AM, Ashley M. Kirchner wrote:
>
> I'm trying to extract data coming from an exec() call. The exec() call is
> performing an ncdump on a netCDF file:
>
> <?php
> $filename = "mlab.20110101.cdf";
> exec("/usr/bin/ncdump -l 2048 -v wmax ".$filename, $output);
> echo "---\n";
> print_r($output);
> echo "---\n";
> ?>
>
> This is all fine, however the data comes in with extra information I don't
> need, and the data I do need is in a long string format:
>
> Array
> (
> [0] => netcdf mlab.20110101 {
> [1] => dimensions:
> [2] => time = UNLIMITED ; // (288 currently)
> [3] => variables:
> [4] => int base_time ;
> [5] => int samp_secs ;
> [6] => float lat ;
> [7] => float lon ;
> [8] => float alt ;
> [9] => int station ;
> [10] => float time_offset(time) ;
> [11] => float tdry(time) ;
> [12] => float rh(time) ;
> [13] => float pres(time) ;
> [14] => float cpres0(time) ;
> [15] => float dp(time) ;
> [16] => float wdir(time) ;
> [17] => float wspd(time) ;
> [18] => float wmax(time) ;
> [19] => float wsdev(time) ;
> [20] => float wchill(time) ;
> [21] => float raina(time) ;
> [22] => float raina24(time) ;
> [23] => float bat(time) ;
> [24] => data:
> [25] =>
> [26] => wmax = 5, 5, 5, 5.4, 5.7, 5.1, 7.1, 6.1, 4.4, 9.5, 13.5, 14.4,
> 11.1, 9.6, 10.5, 10.6, 11.1, 10, 15.3, 17.2, 16.9, 16, 13.9, 16.7, 15.3, 18.3,
> 17.2, 16.3, 15.9, 18.9, 17.7, 19.7, 19.7, 16.6, 16.4, 16, 14.6, 14.9, 14, 16.7,
> 18.3, 16.2, 18.4, 15.4, 15.3, 13.3, 14.8, 15.6, 15.1, 14.7, 13.8, 14.2, 18,
> 16.7, 16.6, 15.6, 15.8, 17.6, 17.4, 20.3, 17.4, 21.3, 18.7, 16.7, 15.4, 17.5,
> 17.3, 17.7, 20.4, 17.5, 16.8, 18.1, 15.9, 17.8, 17.3, 13.9, 16.2, 17.4, 19.8,
> 17.5, 19, 20, 20.3, 20.4, 20.8, 21.6, 26.4, 23.1, 21.3, 19.9, 20.1, 21.1, 22.1,
> 22.5, 21.2, 20.2, 22.2, 21.6, 19.6, 21.1, 21.7, 21, 20.8, 23.7, 26.6, 21.2,
> 23.8, 23.3, 23.5, 23.9, 21.4, 22.1, 23.5, 22.8, 23, 21.8, 22.2, 25.6, 21.9,
> 22.8, 26.2, 24.2, 23.6, 25.5, 26.8, 25.6, 27.4, 24.5, 23.5, 22.1, 23.1, 25.5,
> 22.5, 22.5, 23.8, 21.8, 22.6, 23.5, 24, 23, 22.3, 21.6, 23.6, 20.5, 21, 19.4,
> 23.6, 19.2, 18, 19.2, 20.5, 19.3, 19.1, 20.4, 18, 17.8, 18.4, 19.4, 21, 18.3,
> 20.4, 21.2, 22.1, 20.1, 17.3, 17.2, 17.6, 17.2, 19.9, 21, 20.6, 21.5, 23.8, 25,
> 24, 23.9, 23.5, 27.7, 21.1, 20.8, 20.1, 18.6, 21, 18.7, 19.9, 16.4, 16.3, 17.3,
> 11.8, 11.4, 15.2, 12.4, 14.2, 16.3, 21.6, 25, 19, 7.7, 9.7, 15.7, 7, 11.1, 10.3,
> 11.2, 14.8, 11.7, 5.5, 5.5, 5.5, 6.9, 7.6, 6.5, 6.4, 6.7, 6.7, 4.9, 5.1, 4.7,
> 5.7, 5.5, 9.2, 6.2, 7.1, 7.7, 6.5, 5.5, 6, 6.4, 7, 6.2, 6.7, 4.7, 3.8, 9.2, 8.1,
> 7.6, 6.8, 6.3, 7.1, 10.5, 8, 9.9, 10.2, 12, 9.4, 14, 18, 11.9, 17.7, 20.9, 18.8,
> 17.4, 13.5, 13.8, 12.6, 5.5, 6.1, 6.6, 6.3, 6.3, 5.1, 7.7, 5.8, 5.4, 4.9, 4.5,
> 4.9, 4.7, 5, 4.8, 4.5, 5.6, 5.9, 4.6, 5.7, 7.2, 6.1, 6.4, 5.4, 6.1, 5.6, 5.9,
> 6.4, 9.5, 11.2, 15.8, 15, 13.6 ;
> [27] => }
> )
>
> ncdump doesn't provide an option to suppress the header information, and as
> you can hopefully tell, the data I'm looking for is in one long string at key
> position 26.
>
> How can I extract what I need from that (wmax) and have it as an array: wmax
> = array(5, 5, ...)
>
> This is only one variable. I will be pulling more variables out, and they
> all come out the same way as above, as strings. The headers might change, so I
> can't simply say ignore the first 0-25 keys and expect what I need to be at
> position 26. I need a reliable way of detecting where the data section starts.
> And I need to convert the strings into arrays for each data set.
>
> Suggestions?
>
Here is a one liner that assumes a lot
print_r(explode(', ', substr($output[count($output)-2)], 7));
Now, if you want a little more error checking and forgiveness, try this
<?php
### all your stuff here ###
$wmax = null;
# Loop it all...
foreach ( $output AS $line ) {
# check to see if line starts with what I'm searching for...
if ( strpos($line, 'wmax = ') === 0 ) {
# Found something, strip beginning of string and explode rest
$wmax = explode(', ', substr($line, 7));
# Since I found it, I don't need to continue; drop out
break;
}
}
# See if I have an array()
if ( is_array($wmax) ) {
# We have an array, now see if it is populated at all
if ( $cnt = count($wmax) ) {
# Great, tell them how many values we found
echo 'I found '.$cnt.' wmax values and here they are.'.PHP_EOL;
# Show them the values
print_r($wmax);
} else {
# Darn, our array was empty, lets tell them the bad news...
echo 'no wmax values were set';
}
} else {
# Dang, I couldn't find the wmax line, better let them know!
echo 'could not identify the wmax values returned';
}
?>
Jim Lucas
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