I'm learning php. Novice. For that purpouse I decided to start with a flat file comment system.
I'm using ajax to post to php that writes data to a flat-file database.
Similar to: 12.01.2011¦¦the name¦¦the comment¦¦md5email¦¦0
Where '0' is the start number of comment 'likes'...thumbs-up.
Everything is working fine with ajax. Even the comment delete.
At page load jquery counts the comments (starting from 0) and assigns to each's comment-'like' an numbered id.
That number is than posted via ajax to php, resulting the file line number to modify.
That system works great for identifying the line to delete.
And it deletes the right line!
Now, having the line (or string?) number. How to:
Search the file for that line. (foreach...?!...)
Finded the line - split it into arrays. (Explode...?)
And increment by 1 the defined array value.
Limit maximum likes to 99.
(1 per user session).
Write file, close and so on.
- I just can't start count the 'like' clicks.
Please help.
Any ideas?
Thanks in advance!
$lines = file($filename, FILE_IGNORE_NEW_LINES);
$entry = explode('¦¦', $lines[$linenumber]);
$entry[4]++;
$lines[$lineNumber] = implode('¦¦', $entry);
file_put_contents($filename, implode("\n", $lines));
Related
Quick update: The reason I need this solution is that this one php file is used to expand the flat file for about hundred users (that all use the same php file, but have their own flat files)
SOLUTION:
I worked with this one more day, rephrased the question and got a really great answer. I add it here for future help for others:
$content = file_get_contents("newstest.db");
$content = preg_replace('/(^ID:.*\S)/im', '$1value4:::', $content);
$content = preg_replace('/(^\d+.*\S)/im', '$1:::', $content);
file_put_contents("newstest.db", $content);
The original content of the flat file used when testing the code was:
ID:::value1:::value2:::value3:::
1:::My:::first:::line:::
2:::My:::second:::line:::
3:::Your:::third:::line:::
ORIGINAL QUESTION:
I have a PHP script I am trying to modify. Being a PHP newbie, and have searched both here and on Google without finding a solution, I ask here.
I need to add more values (columns) in the flat file, automatically if the "column" does not exist from before.
Because this one PHP file is shared with many users (each with their own flat file), I need a way to automatically add new "columns" in their flat files if the column does not exist. Doing it manually is very time consuming, and I bet there is an easy way.
INFO:
The flat file is named "newstest.db"
The flat file has this layout:
id:::title:::short:::long:::author:::email:::value1:::value2:::value3:::
So the divider is :::
I understand the basics, that I need to add for instance "value4:::" after "value3:::" in the first line of the news.db, then add ::: to the other existing lines to update all lines and prepare for the new "value4"
Today the php uses this to connect to the flat file:
($filesource is the path to the flat file including it's name. Unique for each user.)
$connect_to_file = connect_pb ($filesource);
And to write to the file I use:
insert_pb($filesource,"$new_id:::$title:::$short:::$long:::$author:::$email:::$value1:::::::::");
(As you see in this case value 2 and 3 is not used in this case, but are in others.)
QUESTION:
Is there a quick/ existing php code to use to add a new column if it doesn't already exist? Or do I need to make the php code for this specific task?
I understand that the code must do something along:
If "value4" does not exist in line 0 in $filesource
then add "value4:::" at the end of line 0,
and for each of the other lines add ":::" at the end.
I don't know where to start, but I have tried for some hours.
I understand this:
update_pb(pathtofiletosaveto,"id","x == (ID of news)","value in first line","value to add");
But I don't know how to make an if statement as in 1) above, neither how to update the line 0 in the flat file to add "value4:::" at the end etc.
MY CODE (does not work as intended):
OR, may be I need to read only line 1 in the file (newstest.db), and then exchange that with a new line if "value4" is not in line 1?
A suggestion, but I don't know how do all:
(It's probably full of errors, as I have tried to read up and find examples and combining code.)
<?php
// specify the file
$file_source="newstest.db";
// get the content of the file
$newscontent = file($file_source, true);
$lines ='';
// handle the content, add "value4:::" and ":::" to the lines
foreach ($newscontent as $line_num => $linehere) {
// add "value4:::" at the end of first line only, and put it in memory
if($line_num[0]) {$lines .= $linehere.'value4:::';}
else {
// then add ":::" to the other lines and add them to memory
$lines .= $linehere.':::';
}
// echo results just to see what is going on
//echo 'Line nr'.$line_num.':<br />'.$lines.'<br /><br />';
}
// add
// to show the result
echo "Here is the result:<br /><br />".$lines."<br /><br />";
//Write new content to $file_source
$f = fopen($file_source, 'w');
fwrite($f,$lines);
fclose($f);
echo "done updating database flat file";
?>
This ALMOST works...
But it does NOT add "value4:::" to the end of the first line,
and it does not add ":::" to the end of the next lines, but to the beginning...
So a couple of questions remains:
1) How can I search in line 0 after "value4", and then write "value4:::" at the end of the line?
2) How can I add ":::" at the end of each line, and not in the beginning?
I kindly ask you to either help me with this.
Do you absolutely have to use PHP for this task? It seems like something you only need to do once, and is much easier to do in a different way.
For example, if you have a *nix shell with sed, sed -i 's/$/:::/' <file> will do that task for you.
I'm using the Sebastian Bergmann PHPUnit selenium webdriver.
Current I have:
$csv = file_get_contents('functions.csv', NULL,NULL,1);
var_dump($csv);
// select 1 random line here
This will load my CSV file and give me all possible data from the file.
It has multiple rows for example:
Xenoloog-FUNC/8_4980
Xylofonist-FUNC/8_4981
IJscoman-FUNC/8_4982
Question: How can I get that data randomly?
I just want to use 1 ( random) line of data.
Would it be easier to just grab 1 (random) line of the file instead of everything?
Split the string into an array, then grab a random index from that array:
$lines = explode("\n", $csv);
$item = $lines[array_rand($lines)];
You could use the offset and maxlen parameters to grab part of the file using file_get_contents. You could also use fseek after fopen to select part of a file. These functions both take numbers of bytes as arguments. This post has a little more information:
Get part of a file by byte number in php
It may require some hacking to translate a particular row-index of a CSV file to a byte offset. You might need to generate and load a small meta-data file which contains a list of bytes-occupancies for each row of of CSV data. That would probably help.
I have text files containing structured data (it is a proprietary format and not something simple or common like CSV). I'm trying to put this data into a database. The text files are as large as 50GB so it's impossible for me to read the entire file into memory, extract it into an array, then process it into the database.
The text files are structured in such a way that data on a particular "item" (a specific id in the database) can have multiple lines (new lines) of information in the text file. Items in the text file always start with a line that begins with '01' and can have an infinite number of additional lines (all one after the other), that will all start with 02 or 03 ... up to 08. A new item begins when a new line starts with 01.
01some_data_about_the_first_item
02some_more_data_about_the_first_item
05more_data_about_the_first_item
01the_first_line_of_the_second_item
I'd like to use PHP to process this data.
How can I load a piece of this text file into memory where I can analyze it, get all the lines for an item, and then process it? Is there a way to load all lines up to the next line that starts with 01, process that data, then begin the next scan of the text file at the end of the last scan?
Processing the data once I've loaded pieces of it into memory is not the problem.
Sure. Since you tagged the question with csv, I'll assume you have a CSV file. In that case, fgetcsv is a good function to use, which get one line from the file at a time. Using that you can get as many lines as you need for one record, then process it, then continue with the next one. Rough mockup:
$fh = fopen('file.csv', 'r');
$record = array();
do {
$line = fgetcsv($fh);
if ($line && $line[0] != '01') {
// any line that does not start with 01 is part of the current record,
// adjust condition as necessary
$record[] = $line;
} else if ($record) {
/* put current $record into database */
// start next record
$record = array($line);
}
} while ($line);
Here is a start:
<?php
$fp=fopen('big.txt','r');
while($line=fgets($fp)){
$number=substr($line,0,2);
$data=substr($line,2);
// proccess each line
echo $number.' - '.$data;
}
fclose($fp);
?>
How can i get a particular line in a 3 gig text file. The lines are delimited by \n. And i need to be able to get any line on demand.
How can this be done? Only one line need be returned. And i would not like to use any system calls.
Note: There is the same question elsewhere regarding how to do this in bash. I would like to compare it with the PHP equiv.
Update: Each line is the same length the whole way thru.
Without keeping some sort of index to the file, you would need to read all of it until you've encountered x number of \n characters. I see that nickf has just posted some way of doing that, so I won't repeat it.
To do this repeatedly in an efficient manner, you will need to build an index. Store some known file positions for certain (or all) line numbers once, which you can then use to seek to the right location using fseek.
Edit: if each line is the same length, you do not need the index.
$myfile = fopen($fileName, "r");
fseek($myfile, $lineLength * $lineNumber);
$line = fgets($myfile);
fclose($myfile);
Line number is 0 based in this example, so you may need to subtract one first. The line length includes the \n character.
There is little discussion of the problem and no mention is made of how the 'one line' should be referenced (by number, some value within it, etc.) so below is just a guess as to what you're wanting.
If you're not averse to using an object (it might be 'too high level', perhaps) and wish to reference the line by offset, then SplFileObject (available as of PHP 5.1.0) could be used. See the following basic example:
$file = new SplFileObject('myreallyhugefile.dat');
$file->seek(12345689); // seek to line 123456790
echo $file->current(); // or simply, echo $file
That particular method (seek) requires scanning through the file line-by-line. However, if as you say all the lines are the same length then you can instead use fseek to get where you want to go much, much faster.
$line_length = 1024; // each line is 1 KB line
$file->fseek($line_length * 1234567); // seek lots of bytes
echo $file->current(); // echo line 1234568
You said each line has the same length, so you can use fopen() in combination with fseek() to get a line quickly.
http://ch2.php.net/manual/en/function.fseek.php
The only way I can think to do it would be like this:
function getLine($fileName, $num) {
$fh = fopen($fileName, 'r');
for ($i = 0; $i < $num && ($line = fgets($fh)); ++$i);
return $line;
}
While this is not a solution exactly, how come you are needing to pull out one line from a 3 gig text file? is perfomance an issue or can this run a leisurely pace?
If you need pull lots of lines out of this file at different points in time, i would definately suggest putting this data into a DB of some kind. SQLite maybe your friend here as its very simple but not great with lots of scripts/people accessing it at one time.
Using PHP, it's possible to read off the contents of a file using fopen and fgets. Each time fgets is called, it returns the next line in the file.
How does fgets know what line to read? In other words, how does it know that it last read line 5, so it should return the contents of line 6 this time? Is there a way for me to access that line-number data?
(I know it's possible to do something similar by reading the entire contents of the file into an array with file, but I'd like to accomplish this with fopen.)
There is a "position" kept in memory for each file that is opened ; it is automatically updated each time you are reading a line/character/whatever from the file.
You can get this position with ftell, and modify it with fseek :
ftell — Returns the current position
of the file read/write pointer
fseek — Seeks on a file pointer
You can also use rewind to... rewind... the position of that pointer.
This is not getting you a position as a line number, but closer to a position as a character number (actually, you are getting the position as a number of bytes from the beginning of the file) ; when you have that, reading a line is just a metter of reading characters until yu hit an end of line character.
BTW : as far as I remember, these functions are coming from the C language -- PHP itself being written in C ;-)
Files are just a stream of data, read from the beginning to the end. The OS will remember the position you've read so far in that file. If needed, doing so in the application as well is fairly simple. The OS only cares about byte positions though, not lines.
Just imagine dealing out a deck of 52 card sequentially. You hand off the first card. Next time the 2. card. When you want to give out the 3. card , you don't need to start counting from the start again, or even remembering where you were you just hand out the next available card, and that'll be the third.
It might be a bit more work that's needed to read lines, since you'd want to buffer data read from the actual file for preformance sake, but it's not that much more to it than to record the offset of the last piece of data you handed out, find the next newline character and hand off all the data between those 2 points.
PHP nor the OS has no real need to keep the line number around, since all the system care about is "next line". If you want to know the line number, you keep a counter and increment it every time your app reads a line.
$lineno=0;
while (!feof($handle)) {
$buffer = fgets($handle, 4096);
lineno++; // keep track of the line number
...
}
i hav this old sample i hob its can help you :)
$File = file('path');
$array = array();
$linenr = 5;
foreach( $File AS $line_num => $line )
{
$array = array_push( $array , $line );
}
echo $array[($linenr-1)];
You could just call fgets and increment a var $line_number each time you call it. That would tell you the line it is on.