php删除文本文件中重复行的方法
发布:smiling 来源: PHP粉丝网 添加日期:2021-05-25 10:26:36 浏览: 评论:0
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:
- /**
- * 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:
- // 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, ';');
Tags: php删除文本文件重复行
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