php删除文本文件中重复行的方法
php删除文本文件中重复行的方法
本文实例讲述了php删除文本文件中重复行的方法。分享给大家供大家参考。具体分析如下：
这个php函数用来删除文件中的重复行，还可以指定是否忽略大小写，和指定换行符
?
|
1 立即学习“PHP免费学习笔记（深入）”； 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 |
/** * 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 // 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：
?
|
1 立即学习“PHP免费学习笔记（深入）”； 2 3 4 5 6 7 8 9 10 11 12 13 |
// 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, ';'); |
希望本文所述对大家的php程序设计有所帮助。
