Remove duplicated lines

Submitted by:Jhon Jhon

Date added:13 October, 2015

Category:PHP

This function removes all duplicated lines of the given text file.

Tags: remove lines , duplicate line

Code Snippet:

/**
* 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));
}

 
 

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