PGFplot - Create a new column from the hash value of another column

Question

I want to calculate the hash value of several columns and store the unique value in another column using pgfplotstable.

In my shown MWE I just try this approach with two columns X & Y. I want to combine them (just concatenate the strings) and calculate the hash value.

Unfortunately, the function \pgfplotstablegetelem{\pgfplotstablerow}{X}\of\mydata is not working for me.

I get the error message:

Package pgfplots Error: Sorry, row `2' does not exist in table <inline_table>.

So this is not working... Can anyone help me? :)

MWE

\documentclass[10pt,a4paper]{article}
\usepackage{pgfplotstable}
\usepackage{xstring}
\pgfplotsset{compat=newest}
\newcommand{\calcHash}[1]{
\noexpand\StrLeft{\pdfmdfivesum{#1}}{3}
}
\pgfplotstableread[]{
X Y
1 a
2 b
5 c
}\mydata
\begin{document}
\pgfplotstablecreatecol[
create col/assign/.code={
    %\pgfplotstablegetelem{\pgfplotstablerow}{X}\of\mydata
    %\pgfmathsetmacro\xValue{\pgfplotsretval}
    %\pgfplotstablegetelem{\pgfplotstablerow}{Y}\of\mydata
    %\pgfmathsetmacro\yValue{\pgfplotsretval}
    \edef\myHash{\noexpand\calcHash{abc}} % I want to replace "abc" with "\xValue\yValue"
    \pgfkeyslet{/pgfplots/table/create col/next content}\myHash
}]{ID}{\mydata}
\pgfplotstablegetrowsof{\mydata}
\pgfmathtruncatemacro\myDataRows{\pgfplotsretval-1}
\pgfplotstabletypeset[string type]{\mydata}
\end{document}

RESULT

Answer 1

You can simply use \thisrow{<column>} instead:

\documentclass[10pt,a4paper]{article}
\usepackage{pgfplotstable}
\usepackage{xstring}
\pgfplotsset{compat=newest}
\newcommand{\calcHash}[1]{
\noexpand\StrLeft{\pdfmdfivesum{#1}}{3}
}
\pgfplotstableread[]{
X Y
1 a
2 b
5 c
}\mydata
\begin{document}
\pgfplotstablecreatecol[
  create col/assign/.code={
    \edef\myHash{\pdfmdfivesum{\thisrow{X}\thisrow{Y}}}%
    \pgfkeyslet{/pgfplots/table/create col/next content}\myHash
}]{ID}{\mydata}
\pgfplotstablegetrowsof{\mydata}
\pgfmathtruncatemacro\myDataRows{\pgfplotsretval-1}
\pgfplotstabletypeset[string type]{\mydata}
\end{document}