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5049 :: Read lines from file thats in a variable

• Neil_H (orginal) [2019-07-26T15:57:38+02:00] view original

  Okay, so I read in a file like this:

  var testFileAll = readFile(testFilePath)

  And now I want to do some work on each line, yet this doesn't work:

  for line in lines(testFileAll):

  echo line

  So is there no lines procedure for a file that's been read in? I really don't want to have to copy between memfiles, streams etc just to access each line.

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• kidandcat (orginal) [2019-07-26T16:02:46+02:00] view original

  import strutils for line in testFileAll.split("\n"): #your code

  Run

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• Neil_H (orginal) [2019-07-26T16:11:48+02:00] view original

  That will do it, thanks.

  The only think that concerns me is writing the lines back to memory after ive edited them in some way, like a Regex routine does when it goes through the whole file.... I guess I will have to deal with that when I come to it.

  Cheers

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• Stefan_Salewski (orginal) [2019-07-26T16:26:40+02:00] view original

  You may try https://nim-lang.org/docs/strutils.html#splitLines.i%2Cstring, and you may store the lines in a seq[string] so that you can write them out after processing.

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• Neil_H (orginal) [2019-07-26T17:02:07+02:00] view original

  Thanks Stefan, that will definitely come in useful as well.

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• cdunn2001 (orginal) [2019-07-31T07:26:13+02:00] view original

  StringStream is another option. https://nim-lang.org/docs/streams.html

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• Neil_H (orginal) [2019-07-31T13:34:01+02:00] view original

  Thanks, but as stated in my first comment... I don't want to go down the route of using streams etc.

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• enthus1ast (orginal) [2019-07-31T14:45:02+02:00] view original

  Why you read it in completely in the first place when you want to operate on lines? When you mystring.split('n') you double the amounth of memory used. For small files this seems ok but for larger ones your programm could explode. It's much better to use the splitLines iterator as Stefan_Salewski pointed out. This way you only have to store the current line in memory.

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• Neil_H (orginal) [2019-07-31T15:03:37+02:00] view original

  Because I have Regex already done that will only work on the whole file.

  And I am going to use the splitLines iterator, but the file will also be in memory at the same time, in this day an age of large amounts of ram, and since I will only be dealing with certain types of source files I don't think that will be a major problem.

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