[SOLVED] Get line of string from a text file?

[Pentti]

Is it possible to get a line of a string from a text file?

A function that would open a text file, search for a specified string and if it is found, it would ge the line where the string is located in text file.

 

If my text file was something like this:

Line1
Line2
Line3
Line4

If I was finding a line of the string "Line3", function would return as "3".

[markjoe]

The file() function returns the contents of a file in an array by line. So..

 

<?php
$myfile=file("/path/to/file.txt");
$linecount=0;
foreach($myfile as $myline){
   $linecount++;
   if($myline=="searchstring"){//just an example, use what ever search method fits
      echo $linecount;
   }
}
?>

 

OR maybe

 

<?php
$myfile=file("/path/to/file.txt");
foreach($myfile as $key=>$myline){
   if($myline=="searchstring"){//just an example, use what ever search method fits
      echo ($key+1);
   }
}
?>

 

I did not test either of these, but should be a start, if I am understanding you anyway.

[BlueSkyIS]

i was beat to the answer, but here's my version...

 

$test_string = "somestring";
$c_array = file("./yourfile.txt");
$c_size = count($c_array);

for ($i=0; $i<$c_size;$i++) {
    if (trim($c_array[$i]) == $test_string) {
       echo "$test_string was found on line ".($i + 1);
    }
}

[Pentti]

Thanks guys!

But does those work only when you search for one letter? Like you search "a" or "3".

 

I was finding something that will find a whole word and get the line.

[markjoe]

I was only trying to illustrate reading the file and returning the line, the search method can be nearly anything.

$myline=="texttofind" - would attempt to match the entire line

strstr("texttofind",$myline) - would find the first occurance of "texttofind"

preg_match("/texttofind/",$myline) - uses regular expression to match any text (or pattern) in line

 

I suspect strstr() may be the best option for you.

http://us2.php.net/manual/en/function.strstr.php

It will work just as well, to do strstr("3",$myline)

It would then find the first "3" on a line.

 

[Pentti]

Guys! Guys!!

 

<?php function getstrline($searchstr, $file){
  $c_array = file($file);
  $c_size = count($c_array);

  for ($i=0; $i < $c_size; $i++){
    if(strpos(Trim($c_array[$i]), $searchstr))
   	return $i;
  }
} ?>

 

Can someone tell me whats wrong with that? It will return 0 in the loop, but I tried like this:

<?php function getstrline($searchstr, $file){
  $c_array = file($file);
  $c_size = count($c_array);

  return strpos(Trim($c_array[0]), $searchstr)
} ?>

It worked like that. When I wrote the first word or part of word of the text file on $searchstr.

 

Please, can someone tell me whats wrong with the loop, if the loop worked then this whole thing would work, i copied it from BlueSkyIS and changed it to check strpos.

[roopurt18]

There is already a built in function to open a file and return everything as an array.  There is already a built in array search function.

 

  $file = file("the/file");
  $key = array_search($search, $file);
  if($key === FALSE){
    echo "Not found";
  }

 

If you want all matching lines, use the array_keys() function.

[Pentti]

There is already a built in function to open a file and return everything as an array.  There is already a built in array search function.

 

  $file = file("the/file");
  $key = array_search($search, $file);
  if($key === FALSE){
    echo "Not found";
  }

 

If you want all matching lines, use the array_keys() function.

I dont quite understand how to use that, or where I need that, but the first problem is now:

1. The function doesnt work that I posted above, strpos will return true ( > 0 ) without loop, but it wont return when its in the loop. I would like to have that fixed/told why it wont work.

[roopurt18]

The code I gave you IS the function body.  Just make it return $key and you're done.  You don't need to loop or perform any comparisons yourself; there are already built in functions to handle this stuff.  Why re-invent the wheel?

[markjoe]

My deepest apologies roopurt18... I did not know of that function.

 

That will work as long as the matching method used by array_search() is the way he wants to match.

 

<?php
function getstrline($searchstr, $file){
   $myfile=file($file);
   $key=array_search($searchstr,$myfile);
   return ($key+1);
}
?>

 

How about that, Pentti?

 

... one reason to loop through the array yourself would be if you want to use regex to make your match. Unless I am missing something with array_search(), it does not appear to support regex.

[Pentti]

My deepest apologies roopurt18... I did not know of that function.

 

That will work as long as the matching method used by array_search() is the way he wants to match.

 

<?php
function getstrline($searchstr, $file){
   $myfile=file($file);
   $key=array_search($searchstr,$myfile);
   return ($key+1);
}
?>

 

How about that, Pentti?

 

... one reason to loop through the array yourself would be if you want to use regex to make your match. Unless I am missing something with array_search(), it does not appear to support regex.

Thanks, but somethings wrong with array_search.

It will only return the line where word is if I search for the word thats the last word in the text file!

 

Test it yourself!

php code:

<?php
function getstrline($searchstr, $file){
  $myfile = file($file);
  $key = array_search($searchstr, $myfile);
  return ("'$searchstr' at line: $key");
}

Echo getstrline("Line4", "test.txt");
?>

 

text file:

Line0
Line1
Line2
Line3
Line4

 

result when finding "Line4":

'Line4' at line: 4

 

result when finding "Line3" (or lower):

'Line3' at line:

[Pentti]

Thanks for the help guys! But I attempted to make a working function, to work just like I wanted it to work.

If anyone wants to see the function, here it is:

 

<?php
function getstrline($searchstr, $file){
  $c_array = file($file);
  $c_size = count($c_array);

  $i = 0;
  while($i <= $c_size - 1){
    if(strpos(Trim($c_array[$i]), $searchstr))
    return $i;
    $i++;
  }
}
?>

[roopurt18]

You might want the function to return FALSE or -1 as the last line of the function for cases where the search string is not found.

 

Also, instead of calling count() and using a while loop, you could use a foreach loop, which is intended for looping over arrays.

 

This is a very, very minor optimization note, but you can apply the concept to other areas of your code.

while($i <= $c_size - 1){

That is perfectly fine for your while loop, but you are forcing the interpreter to re-evaluate the expression $c_size - 1 each time through the loop.  So let's say the file was 1000 lines long, the expression $c_size - 1 will be calculated 1000 times; however, it's always going to be the same result.  This means we can move the calculation outside the loop so that it is only ever calculated once:

$c_size--;
while($i <= $c_size){

You can eliminate the -1 operation altogether by changing the comparison in the while loop as well:

while($i < $c_size){

Like I started off by saying, that is a very minor optimization and barely worth performing; it's only going to shave maybe a millisecond off your execution time, if that.  However, if the $c_size - 1 had been a different, more expensive (expensive in terms of computation time) operation, such as a function call, it's a good optimization to make.

 

Lastly:

    if(strpos(Trim($c_array[$i]), $searchstr))
    return $i;

That code is perfectly legal, but I highly recommend always, always, always placing curly brackets around the bodies of your conditional statements and loops, even when they're a single line and optional.  The reason for this is its very easy to add another line to the body of a conditional or loop to enhance functionality or for debugging purposes but then forget to add the curly brackets, which breaks the loop / conditional.  It only takes an extra second to type the keystrokes and sure it adds one more line to your source file, but honestly it can save you a good half hour or more of frustration down the road.

  if(strpos(trim($c_array[$i]), $searchstr)){
    return $i
  }

You should also always indent the bodies of your conditionals and loops as well, to enhance readability.

 

I only bring this stuff up now because you are learning so its easier to develop good habits now rather than break bad habits later.  When I was learning to program, my sources (books / professors) said the same things and you just have to take it on faith.  I decided to listen and I can't tell you how many times throughout college I saw people have trouble debugging or fixing their code because they didn't do little things like that.

 

Best of luck to you.

[Pentti]

Thanks for the tips roopurt18!

(Btw, Im not totally noob at programming, I know pascal pretty well, but in php I just cant find some functions that I need.)