[Gnuplot-info] Plotting partial file based on 3rd column

[Thor A. <ta...@to...>]

Hi,

I was under the impression that it is possible to plot only parts of a data
file with the ternary operator (?:), strcol() and missing ('?'), but I get
strange results.

My data file contains:

8<------8<------8<------8<------
cat << EOF > data
1 2 A
2 3 A
1 1 B
2 4 B
3 2 A
4 3 A
EOF
8<------8<------8<------8<------

Now if try to plot the lines with 'B' in the third column:

echo "set table; plot 'data' u 1:((strcol(3) eq 'B')? \$2 : '?')" | gnuplot 

The result is:

8<------8<------8<------8<------
# Curve 0 of 1, 6 points
# Curve title: "'data' u 1:((strcol(3) eq 'B')? $2 : '?')"
# x y type
 1  1.89869e-267  i
 2  1.89869e-267  i
 1  1  i
 2  4  i
 3  4  i
 4  4  i
8<------8<------8<------8<------

Which is not what I expected. Am I doing it wrong or is this a bug?

The above was tested with a recent cvs version of Gnuplot.

gnuplot> show version long

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-- 
best regards
Thor Andreassen