How PHP deletes duplicate rows in a text file

how PHP deletes duplicate rows in a text file

The example in this article describes how PHP deletes duplicate rows in a text file. Share to everyone for your reference. The specific analysis is as follows:

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

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/** * Removeduplicatedlines * This function removes all duplicated lines of the given T Ext 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 '. $Filepat H. ' does not exist! '; Die ($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 (); $Duplicates = 0; Go trough all lines to the given file for ($Line =0 $Line < count ($Lines); $Line + +) {//Trim whitespace for the Curr ENT 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 to how many lines got removed return implode ($NewLine, Array_values ($LineArray)); }

Use Example:

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Example 1//Removes all duplicated lines of the "file Definied in the" $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 can define which character//should as New Line indicator. In this case//The example file looks like ' Foo;bar;foo;foo ' and would/is replaced with ' Foo;bar ' removeduplicatedlines (' Test.txt ', false, '; ');

I hope this article will help you with your PHP program design.