本文實例講述了php刪除文本文件中重復行的方法。分享給大家供大家參考。具體分析如下：
這個php函數用來刪除文件中的重復行，還可以指定是否忽略大小寫，和指定換行符
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/** * 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)); } |
使用范例：
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// 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, ';'); |
希望本文所述對大家的php程序設計有所幫助。
