php operation text file to delete duplicate lines
This article mainly introduces how to delete duplicate lines in text files using PHP. Interested friends can refer to it. I hope it will be helpful to everyone.
The example in this article describes the method of deleting duplicate lines in text files in PHP. The specific analysis is as follows:
This php function is used to delete duplicate lines in the file. You can also specify whether to ignore case and specify the newline character
/**
* RemoveDuplicatedLines
* This function removes all duplicated lines of the given text file.
*
* @param string
* @param bool
* @return string
*/
function RemoveDuplicatedLines($Filepath, $IgnoreCase=false, $NewLine="\n"){
if (!file_exists($Filepath)){
$ErrorMsg = 'RemoveDuplicatedLines error: ';
$ErrorMsg .= 'The given file ' . $Filepath . ' does not exist!';
die($ErrorMsg);
}
$Content = file_get_contents($Filepath);
$Content = RemoveDuplicatedLinesByString($Content, $IgnoreCase, $NewLine);
// Is the file writeable?
if (!is_writeable($Filepath)){
$ErrorMsg = 'RemoveDuplicatedLines error: ';
$ErrorMsg .= 'The given file ' . $Filepath . ' is not writeable!';
die($ErrorMsg);
}
// Write the new file
$FileResource = fopen($Filepath, 'w+');
fwrite($FileResource, $Content);
fclose($FileResource);
}
/**
* RemoveDuplicatedLinesByString
* This function removes all duplicated lines of the given string.
*
* @param string
* @param bool
* @return string
*/
function RemoveDuplicatedLinesByString($Lines, $IgnoreCase=false, $NewLine="\n"){
if (is_array($Lines))
$Lines = implode($NewLine, $Lines);
$Lines = explode($NewLine, $Lines);
$LineArray = array();
$Duplicates = 0;
// Go trough all lines of the given file
for ($Line=0; $Line < count($Lines); $Line++){
// Trim whitespace for the current line
$CurrentLine = trim($Lines[$Line]);
// Skip empty lines
if ($CurrentLine == '')
continue;
// Use the line contents as array key
$LineKey = $CurrentLine;
if ($IgnoreCase)
$LineKey = strtolower($LineKey);
// Check if the array key already exists,
// if not add it otherwise increase the counter
if (!isset($LineArray[$LineKey]))
$LineArray[$LineKey] = $CurrentLine;
else
$Duplicates++;
}
// Sort the array
asort($LineArray);
// Return how many lines got removed
return implode($NewLine, array_values($LineArray));
}Usage example:
// Example 1 // Removes all duplicated lines of the file definied in the first parameter. $RemovedLinesCount = RemoveDuplicatedLines('test.txt'); print "Removed $RemovedLinesCount duplicate lines from the test.txt file."; // Example 2 (Ignore case) // Same as above, just ignores the line case. RemoveDuplicatedLines('test.txt', true); // Example 3 (Custom new line character) // By using the 3rd parameter you can define which character // should be used as new line indicator. In this case // the example file looks like 'foo;bar;foo;foo' and will // be replaced with 'foo;bar' RemoveDuplicatedLines('test.txt', false, ';');
Summary: The above is the entire content of this article, I hope it will be helpful to everyone's study.
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