I'm trying to read a specific line from a text file using php. Here's the text file:
foo
foo2
How would I get the content of the second line using php? This returns the first line:
<?php
$myFile = "4-24-11.txt";
$fh = fopen($myFile, 'r');
$theData = fgets($fh);
fclose($fh);
echo $theData;
?>
..but I need the second.
Any help would be greatly appreciated
Well, you could do:
$f = fopen($file, 'r');
$line = fgets($f);
fclose($f);
It's not one line, but if you made it one line you'd either be screwed for error checking, or be leaving resources open longer than you need them, so I'd say keep the multiple lines
If you ABSOLUTELY know the file exists, you can use a one-liner:
$line = fgets(fopen($file, 'r'));
The reason is that PHP implements RAII for resources.
That means that when the file handle goes out of scope (which happens immediately after the call to fgets in this case), it will be closed.
$var = "Bill";
$input = "Kate
Johnny
Bill
Kermit";
$output = str_replace($var ."rn", "", $input ."rn");
If you have control over the cron or command, have you considered passing a command-line argument, and reading it with $_SERVER['argv'][0]?
* * * * * /usr/bin/php /path/to/script --cron
In the script:
<?php
if(isset($_SERVER['argv'][0]) and $_SERVER['argv'][0] == '--cron')
$I_AM_CRON = true;
else
$I_AM_CRON = false;
What's in countRowsOfDb()? If it opens the file and counts the lines
in it (and I don't know what else it could do), then it's not going to
find a lot in the final loop, since the creation of the ostream with the
same name will have emptied the file.
More generally, this is a very inefficient way of doing things (and
could easily fail if there were an error in the format of the file).
The best way to handle this is to use an std::vector<Student>, with:
studentVector.push_back( Student( id, name, grade, points, type ) );
in the input loop. In all later loops, studentVector.size() gives the
number of entries, or you can use the iterators.
Even better would be to use std::getline on the
input, then initialize an std::istringstream to parse each line. This
will catch input format errors much more reliably. Something like:
std::string line;
int lineNumber = 0;
while ( std::getline( inDb, line ) ) {
++ lineNumber;
std::istringstream data( line );
if ( data >> id >> name >> grade >> points >> type ) {
studentVector.push_back( Student( id, name, grade, points, type ) );
} else {
std::cerr << "Format error in lne " << lineNumber << std::endl;
}
}
Also, it is generally a better idea to write to separate file, then rename it after having verified that the write worked, i.e.:
std::ofstream outDb( "files/students.dat.new" );
// Do output...
outDb.close();
if ( outDb ) {
remove( "files/students.dat" );
rename( "files/students.dat.new", "files/students.dat" );
} else {
std::cerr << "Write error on output" << std::endl;
}
And of course, any write error should result in a return of
EXIT_FAILURE from main. (This is one case where a global variable
or a singleton is justified—keeping track of the return code.)
file — Reads entire file into an array