[ncl-talk] reading station data

[Debasish Hazra]

Thanks Dave, very helpful information and it worked.

Debasish

On Fri, Feb 6, 2026 at 1:36 PM Dave Allured - NOAA Affiliate <
dave.allured at noaa.gov> wrote:

> To detect the position of the header line, choose a substring in that line
> that (1) will be included exactly in every file that you want to read, and
> (2) is very unlikely to be used anywhere else in any file.  I like the
> third header, "Day_of_Year", but most other headers would also be fine.
> Then locate the line containing this substring.
>
>       iheader = str_match_ind (line(:) .eq. "Day_of_Year")
>       idata = iheader + 1
>
> Then use these indices in place of the previous hard-coded line indices.
>
>       field_names = str_split(lines(iheader),delim)
>       mhs = str_get_field(lines(idata:),2,delim)       ... etc.
>
> If you want to add quality control, you can use ismissing(iheader) to
> check for missing header line, or unexpected spelling.  You might also want
> to verify that your selected field names are actually the ones that you
> expected.
>
> The problem with the middle column is that you are using an integer format
> code "%3.0i" to print, but you forgot to convert Day from string to
> integer.  I think you need to use toint().  Printing string with a numeric
> format code is always good for chaos.
>
>
> On Fri, Feb 6, 2026 at 10:07 AM Debasish Hazra <debasish.hazra5 at gmail.com>
> wrote:
>
>> Many thanks Dave. It worked fine. I think I need a way to detect the
>> position automatically as I found it does not always start at line 7, that
>> will be helpful.
>> Also, I am trying to write the columns that I read into a csv file, but
>> not getting right for the middle column. Any suggestions? Attached the code
>> and output csv file as well.
>>
>> Debasish.
>>
>> On Fri, Feb 6, 2026 at 2:14 AM Dave Allured - NOAA Affiliate <
>> dave.allured at noaa.gov> wrote:
>>
>>> Debasish, you have almost everything right, except for the position of
>>> field names, and start of data.  You have:
>>>
>>>       field_names = str_split(lines(0),delim)
>>>
>>> But the field names are on line 7, not line 1.  Change this to get the
>>> field names from line 7.  Since NCL uses zero-based indexing, the correct
>>> line index is 7 - 1 = 6.
>>>
>>>       field_names = str_split(lines(6),delim)
>>>
>>> Likewise, data lines start on the next line after the field names, at
>>> line index 7.  This should clear up the header errors:
>>>
>>>       mhs = str_get_field(lines(7:),2,delim)       ... etc.
>>>
>>> If you are processing a lot of data, then the start of data can change
>>> between files.  Can you have start of data hard coded at 7, or do you need
>>> a way to detect the position automatically?
>>>
>>>
>>> On Thu, Feb 5, 2026 at 9:42 AM Debasish Hazra <debasish.hazra5 at gmail.com>
>>> wrote:
>>>
>>>> Thanks Dave and Dennis for your suggestions. I followed the examples
>>>> and created a script to read the file I sent earlier, but it seems to be I
>>>> am still getting some header information in the column I am trying to
>>>> extract. Attached are output and script that was used, any suggestions to
>>>> overcome this issue.
>>>>
>>>> Debasish.
>>>>
>>>> On Tue, Feb 3, 2026 at 5:50 PM Dave Allured - NOAA Affiliate <
>>>> dave.allured at noaa.gov> wrote:
>>>>
>>>>> Debasish, that is a CSV file with header lines.  Use *asciiread* to
>>>>> read the entire file as strings.  Then use string parsing functions such as
>>>>> *str_split_csv* and/or *str_get_field* to get individual columns.
>>>>> Examples *csv_3.ncl* and *csv4_ncl* are close to what you want to do.
>>>>>
>>>>>       https://www.ncl.ucar.edu/Applications/read_csv.shtml
>>>>>
>>>>>
>>>>> On Tue, Feb 3, 2026 at 12:38 PM Debasish Hazra via ncl-talk <
>>>>> ncl-talk at mailman.ucar.edu> wrote:
>>>>>
>>>>>> Hi,
>>>>>> I am trying to read station data with header and column of data, with
>>>>>> COlumn lengths are not equal in files and have attached one example file in
>>>>>> the attachment.  Can someone help to point what ascii read command to be
>>>>>> used to extract time and column information from these files.
>>>>>> Thanks
>>>>>> Debasish.
>>>>>>
>>>>>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://mailman.ucar.edu/pipermail/ncl-talk/attachments/20260207/30210cbf/attachment.htm>