如何在Racket中将巨大的文件加载到字符串或列表中? [英] How to load a huge file into a String or list in Racket?

问题描述

我有一个巨大的文件，需要对其进行操作.巨大如约.五百万个单词.

I have a HUGE file that I need to do operations on. Huge as in approx. half a million words.

我只想将其读取到列表或字符串中，以便稍后使用它.

I just want to read it into a list or String so I can do things with it later.

我也知道我可以使用file-> string或使用file-> list，file-> lines将其加载到字符串中，但是这些似乎花费的时间太长了.

Also I know I could load it into a string using file->string OR use file->list, file->lines, but these seem to take waayy too long.

将其加载到列表中是否正确?

Is this the right way to load it into a list?:

(define my-list (with-input-from-file "myFile.txt" read))

每当我运行程序时，我都会打印出第一行.似乎适用于较小的文件.

Whenever I run my program I just get the first line printed out. Seems to work for smaller files though.

推荐答案

我强烈感觉到您的问题不是将字符串读入，而是将其打印出来.

I have a strong feeling that your problem isn't reading the string in, but rather printing it out.

具体来说，读取这种大小的文件似乎要花费我大约0.03秒的时间.

Specifically, reading a file of this size appears to take me approximately 0.03 seconds.

我使用此程序生成了一个文件:

I generated a file using this program:

#lang racket

(define str
  "Beebe a reeble to one niner big druppy bonker watz. ")

(with-output-to-file "/tmp/foo.txt"
  (λ ()
    (for ([i (in-range (/ 500000 10))])
      (displayln str))))    

然后，我这样阅读:

#lang racket

(define a (time (file->string "/tmp/foo.txt")))

...并产生以下输出:

... and produced this output:

cpu time: 30 real time: 30 gc time: 17

....表示30毫秒.

.... Indicating 30 milliseconds.

请注意，因为我将file->string包裹在define中，所以不是将整个内容打印出来.这将花费很长时间.

Note that because I wrapped the file->string in a define, I was not printing the whole thing out. That would take a long long time.

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