How to access the index of rapidcsv::Document

[empeirikos]

When reading a csv file, rapidcsv uses the first column to create a handy alternative index for accessing different rows. In Python's DataFrame one can access this index using pandas.DataFrame.index. Is there a similar method in rapidcsv; ideally I would like to keep dates as an index but also copy it to a vector of dates that I can use for other purposes.

[d99kris]

Hi @empeirikos - yes rapidcsv provides GetRowNames() for getting a vector of row labels (and similarly a GetColumnNames()).

With this example program:

  rapidcsv::Document doc("examples/colrowhdr.csv", rapidcsv::LabelParams(0, 0));
  std::vector<std::string> rowNames = doc.GetRowNames();
  for (const auto& rowName : rowNames)
  {
    std::cout << rowName << "\n";
  }

The output would be:

2017-02-24
2017-02-23
2017-02-22
2017-02-21
2017-02-17

For input file colrowhdr.csv content:

Date,Open,High,Low,Close,Volume,Adj Close
2017-02-24,64.529999,64.800003,64.139999,64.620003,21705200,64.620003
2017-02-23,64.419998,64.730003,64.190002,64.620003,20235200,64.620003
2017-02-22,64.330002,64.389999,64.050003,64.360001,19259700,64.360001
2017-02-21,64.610001,64.949997,64.449997,64.489998,19384900,64.489998
2017-02-17,64.470001,64.690002,64.300003,64.620003,21234600,64.620003

Hope this helps!

[empeirikos]

Yes it definitely does. Thanks for writing this library!

…

On Sun, 9 Feb 2025 at 04:10, Kristofer Berggren ***@***.***> wrote: Hi @empeirikos <https://github.com/empeirikos> - yes rapidcsv provides GetRowNames() for getting a vector of row labels (and similarly a GetColumnNames()). With this example program: rapidcsv::Document doc("examples/colrowhdr.csv", rapidcsv::LabelParams(0, 0)); std::vector<std::string> rowNames = doc.GetRowNames(); for (const auto& rowName : rowNames) { std::cout << rowName << "\n"; } The output would be: 2017-02-24 2017-02-23 2017-02-22 2017-02-21 2017-02-17 For input file colrowhdr.csv content: Date,Open,High,Low,Close,Volume,Adj Close 2017-02-24,64.529999,64.800003,64.139999,64.620003,21705200,64.620003 2017-02-23,64.419998,64.730003,64.190002,64.620003,20235200,64.620003 2017-02-22,64.330002,64.389999,64.050003,64.360001,19259700,64.360001 2017-02-21,64.610001,64.949997,64.449997,64.489998,19384900,64.489998 2017-02-17,64.470001,64.690002,64.300003,64.620003,21234600,64.620003 Hope this helps! — Reply to this email directly, view it on GitHub <#183 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ATE2KDRU3QKVM6V55BG5IIL2O3ILNAVCNFSM6AAAAABWXWBFT6VHI2DSMVQWIX3LMV43URDJONRXK43TNFXW4Q3PNVWWK3TUHMYTEMJQGY2TQOI> . You are receiving this because you were mentioned.Message ID: ***@***.***>