| Re: Writing a modified .txt file issue [message #85375 is a reply to message #85373] |
Mon, 29 July 2013 15:31   |
David Fanning
Messages: 11724
Registered: August 2001
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Senior Member |
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Heinz Stege writes:
Uh, let me remind you, this guy said he was an IDL "beginner". You guys
are losing me. :-(
Cheers,
David
>
> On Mon, 29 Jul 2013 13:03:02 -0700 (PDT), Phillip Bitzer wrote:
>
>> I also have an ASCII data file that contains both numeric and string columns. I'm not a fan. What I'm doing now is read the whole thing in as a string array:
>>
>> nLines = FILE_LINES(filename)
>> OPENR, lun, filename, /GET_LUN
>> word = STRARR(nLines)
>> READF, lun, word
>> FREE_LUN, lun
>>
>> Then, I loop through each line, using STR_SPLIT to divvy up the fields at the space that separates the columns, and throw them into the output structure (not defined here for simplicity)
>>
>> FOR i=0L, nLines-1 DO BEGIN
>> this_row = STRSPLIT(word[i], ' ', /extract)
>> data[i].date = this_row[0]
>> data[i].time = this_row[1]
>> data[i].latitude = DOUBLE(this_row[2])
>> data[i].longitude = DOUBLE(this_row[3])
>> ....
>> ENDFOR
>>
>> I have been looking for a better/more efficient way of doing this. Can't seem to find a good way, but maybe Coyote has cooked up something :-) ReadCol works about as quickly as my code.
>>
> This type of files typically have much more lines than columns.
> Therefore it is more efficient to run the loop over a few columns than
> over all the lines. The following code more deals with arrays instead
> of scalars:
>
> for i=0,nColumns-2 do begin
> pos=strpos(word,' ')
> data.(i)=strmid(word,0,transpose(pos))
> word=strtrim(strmid(word,transpose(pos)),1)
> end
> data.(nColumns-1)=word
>
> Try it.
>
> Cheers, Heinz
--
David Fanning, Ph.D.
Fanning Software Consulting, Inc.
Coyote's Guide to IDL Programming: http://www.idlcoyote.com/
Sepore ma de ni thue. ("Perhaps thou speakest truth.")
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