Preg_match

Hi Guys,

Think this a simple one but been stuck for a few hours and tearing my hair out...

ive got a serial command querying a GPS dongle which returns an output once queried

$read = $serial->readPort();

Once the query has been returned it give me and output like the following

$GPRMC,120329.000,A,5310.5615,N,00226.2420,W,0.0,10.0,160312,,,A*43

$GPGGA,120329.000,5310.5615,N,00226.2420,W,1,04,25.5,-0.3,M,59.1,M,,0000*52

$GPVTG,10.0,T,,M,0.0,N,0.0,K,A*3C

$PMST200,00,204*1E

$PMST200,00,204*1E

$PMST200,00,204*1E

$PMST200,??,204*1E

$PMST200,??,204*1E

$PMST200,??,204*1E

$PMST200,??,204*1E

$PMST200,??,204*1E

$PMST200,??,204*1E

$GPGLL,5310.5615,N,00226.2420,W,120329.00,A,A*72

$GPGSA,A,3,04,07,10,13,,,,,,,,,36.1,25.5,25.5*06

$PMST200,??,204*1E

$PMST200,??,204*1E

$PMST200,??,204*1E

$PMST200,00,204*1E

$PMST200,00,204*1E

$PMST200,??,204*1E

$PMST200,??,204*1E

$PMST200,??,204*1E

$GPRMC,120330.000,A,5310.5615,N,00226.2420,W,0.0,10.0,160312,,,A*4B

$GPGGA,120330.000,5310.5615,N,00226.2420,W,1,04,25.5,-0.3,M,59.1,M,,0000*5A

$GPVTG,10.0,T,,M,0.0,N,0.0,K,A*3C

$PMST200,??,204*1E

$PMST200,??,204*1E

$PMST200,??,204*1E

$PMST200,??,204*1E

$PMST200,??,204*1E

Im basically trying to preg_match the GPRMC line but recover the full line, i will then explode it later and break it down

by the commas i the string...

$GPRMC,120329.000,A,5310.5615,N,00226.2420,W,0.0,10.0,160312,,,A*43

i need the above line each time i query the dongle rather than all the other stuff it generates

any one got a clean way of doing it?

ive tried this but all it give me is the following..

if (preg_match("/GPMRC/", $read, $result))
{
print "$result[0]";
}  

which give mes this only

root@voyage:/usr/utils/sattrack# ./check_gps.php
GPRMC
root@voyage:/usr/utils/sattrack# 

$str = 'GPRMC,120330.000,A,5310.5615,N,00226.2420,W,0.0,10.0,160312,,,A*4B

$GPGGA,120330.000,5310.5615,N,00226.2420,W,1,04,25.5,-0.3,M,59.1,M,,0000*5A

$GPVTG,10.0,T,,M,0.0,N,0.0,K,A*3C';
preg_match("~^GPRMC.*~",$str,$ms);
print_r($ms);

results:

Array ( [0] => GPRMC,120330.000,A,5310.5615,N,00226.2420,W,0.0,10.0,160312,,,A*4B )

$str = 'GPRMC,120330.000,A,5310.5615,N,00226.2420,W,0.0,10.0,160312,,,A*4B

$GPGGA,120330.000,5310.5615,N,00226.2420,W,1,04,25.5,-0.3,M,59.1,M,,0000*5A

$GPVTG,10.0,T,,M,0.0,N,0.0,K,A*3C';
preg_match("~^GPRMC.*~",$str,$ms);
print_r($ms);

That solution fails with the exact content the OP posted (i.e. the leading dollar sign.)

@cr-ispinternet: Is the line you want always the first line in the output? If so, a better solution might be to get the first line.

$GPRMC_line = array_shift(explode("\n", $gps_output));

Although you may have to play with the delimiter, could be "\n", "\r" or "\n\r"

But, if you need to use regular expression, this would work too

preg_match("#$GPRMC.*#", $input, $match);
$GPRMC_line = $match[0];

That solution fails with the exact content the OP posted (i.e. the leading dollar sign.)

Judging from the OP's attempted regex, i assumed the dollar sign to be irrelevant.

Either way you would simply add it to the beginning of the pattern.

$GPRMC_line = array_shift(explode("\n", $gps_output));

This will not work, if you looked at the OP's example, the desired string appears twice.

What is $read? One huge string, an array where each item in the array is line, a magical pixie elephant?

Judging from the OP's attempted regex, i assumed the dollar sign to be irrelevant.

I agree, it is irrelevant with respect to the data needed, but the previous pattern would not match the lines because the pattern was looking for a line that starts with "GPRMC". Therefore, when run against the sample data provided, there were no matches. The test data showed for that first regex you provided took out the dollar sign, so it worked.

$GPRMC_line = array_shift(explode("\n", $gps_output));

 

This will not work, if you looked at the OP's example, the desired string appears twice.

I did not read every line in detail in his sample input. But, I did specifically state right before that code

Is the line you want always the first line in the output? If so, a better solution might be to get the first line.

And then I also gave a solution that would work across multiple lines, if needed.

Physco,

your suggestion of the following worked a treat

preg_match("#$GPRMC.*#", $input, $match);

$GPRMC_line = $match[0];

gave me an ouput of the following...

root@voyage:/usr/utils/sattrack# ./check_gps.php

GPRMC,001025.000,V,5310.5798,N,00226.2040,W,0.0,0.0,170312,,,N*60

root@voyage:/usr/utils/sattrack#

great thing now is there are a dozen other string i can latch onto using the same regex

but to answer your questions the $ at the start of GPRMC string does infact mean nothing

and the data returned from $read is part of the serial command issued to get the data in the first place

all i need to do now is strip that result now into an array using the , as a delimiter for sectioning

thanks guys )))