regex - Replace line in text file using PHP -

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i have text file following data:

1_fjd 2_skd 3_fks

i want replace part in text file using php. example want this:

find line starts "2_" , replace "2_word", after '2_' being replaced by:'word'. how can in php?

you don't need regex this. try following:

  • load file array using file() , loop through lines
  • check if string starts 2_
  • if does, replace input $word , concatenate $result string
  • if if doesn't, concatenate $result string
  • use file_get_contents() , write result file

code:

$lines = file('file.txt'); $word = 'word'; $result = '';  foreach($lines $line) {     if(substr($line, 0, 2) == '2_') {         $result .= '2_'.$word."\n";     } else {         $result .= $line;     } }  file_put_contents('file.txt', $result);

now, if replace took place, file.txt contain like:

1_fjd 2_word 3_fks

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