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找出列表中最长单词的长度

performance string php

Alex · 技术社区 · 13 年前

列表如下所示:

Lorem ipsum dolor sit amet,
consectetur adipisicing elit,
sed do eiusmod tempor
...

我想将所有单词缩进如下:

Lorem       ipsum       dolor   sit    amet,
consectetur adipisicing elit,
sed         do          eiusmod tempor

(或至少第一列)

我已经使用阵列和 str_pad :

$lines = explode("\n", $text);
$counts = array();

foreach($lines as $line){
  $words = explode(' ', $line);
  foreach($words as $index => $word){
    if(!isset($counts[$index]) || $counts[$index] < strlen($word))
      $counts[$index] = strlen($word);
  }
}

$text = '';

foreach($lines as $line){
  $words = explode(' ', $line);
  foreach($words as $index => $word)
    $text .= str_pad($word, $counts[$index], ' ' , STR_PAD_RIGHT) . ' ';

  $text .= "\n";
}

但由于文本非常大,它占用了相当多的内存。有没有其他方法可以做到这一点,而不用将文本拆分成数组?

1 回复 | 直到 13 年前

jmm 13 年前

如果文件非常大,您可以逐行读取文件,而不是将其全部加载到一次数组 file() .

$fh = fopen("alice.txt", "r");
$fh = fopen("yourfile.txt", "r");

while( !feof($fh) ){

    $line = fgets($fh);
    $Newerline = str_replace("-", " ", $line);

    $textArray = str_word_count($Newerline,1); 

    //now go through the line word by word
    foreach ($textArray as $index => $word){
        trim($word);
        $wordLength = mb_strlen($word);

        //is this word the longest for this column?
        if($wordLength > $longWords[$index]['longestWordlen'] ){
            $longWords[$index]['longestWordlen'] = $wordLength;
            $longWords[$index]['longestWord'] = $word;
        }

    }
    //echo $line;
}
//rewind the file pointer to the beginning
rewind($fh);

ksort($longWords);//associative array will be out of order since longest word shows up differently

//now create a new file to hold the new version
$fileh = fopen( "newFile.txt", "c");

while( !feof($fh) ){
    $line = fgets($fh);
    $Newerline = str_replace("-", " ", $line); 

    $textArray = str_word_count($Newerline,1); 

    $newLine =  "";
    //now go through the line word by word
    foreach ($textArray as $index => $word){
        //set the length of this words column
            $pad_length = $longWords[$index]['longestWordlen'];

            $newLine .= str_pad($word, $pad_length + 1, " ", STR_PAD_RIGHT);

    }
    $newLine .= PHP_EOL;

    //save the newLine to file
    fwrite($fileh, $newLine);

    //echo $newLine;
}

fclose($fileh);
fclose($fh);

这样一次加载一行,一次写入一行。应该使用更少的内存。

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