PHP Action text File delete duplicate lines

This article mainly introduces the PHP operation text file deletion duplicate line, the interest friend's reference, hoped to be helpful to everybody.

The example in this article describes how PHP deletes duplicate rows in a text file. The specific analysis is as follows:

This PHP function is used to delete duplicate rows in a file, to specify whether to ignore the case, and to specify the line break

/** * Removeduplicatedlines * This function removes all duplicated lines of the given text file. * * @param String * @param bool * @return string */function removeduplicatedlines ($Filepath, $IgnoreCase =false, $NewL    Ine= "\ n") {if (!file_exists ($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)) $Line  s = Implode ($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 ($LineArray [$Lin        EKey]) $LineArray [$LineKey] = $CurrentLine;  else $Duplicates + +;  }//Sort the array asort ($LineArray);  Return how many lines got removed return implode ($NewLine, Array_values ($LineArray)); }

Examples of Use:

Example 1//removes all duplicated lines of the file definied in the first parameter. $RemovedLinesCount = Removeduplica Tedlines (' test.txt ');p rint "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 can Defi Ne which character//should is used as new line indicator. The case//The example file looks like ' Foo;bar;foo;foo ' and will//is replaced with ' Foo;bar ' Removeduplicatedlines (' Test.txt ', false, '; ');

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