gnuplot-info

[Gnuplot-info] splot matrix omitting the first row

[kalispera <fan...@gm...>]

Kalispera!

I'm trying to 'splot' a ascii matrix created by a sql query omitting the
first row

I would like to omit the first row (which contains the necessary sql 'group
by' parameter).

I've read the documentation scrupulously, I have found how plot a single row
of a matrix but not how to omit one.

Does someone have a solution? or is it just not possible?

Thanks for your help.

FD
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Re: [Gnuplot-info] splot matrix omitting the first row/column

[kalispera <fan...@gm...>]

>The quick and easy (?) trick is to have the first row starting with a hash
mark ("#").
>Gnuplot will simply ignore this data line.
>
>Cheers,
>Marek Gutowski 

Thanks Marek for your reply, this is a good idea.

Now I'm trying to omit the first column. I've tried to add '?' to the points
of the first but Gnuplot seems to reject it ('bad number in matrix').

Do you any idea? 

Cheers,

FD

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Re: [Gnuplot-info] splot matrix omitting the first row/column

[kalispera <fan...@gm...>]

To omit a column in a matrix I haven't any elegant solution but the following
trick:

I haven't change the value of the column I want to omit so that I can
discard them using 'using' and the ternary '?'

For example:

My matrix is:

0.5     6     1     1
1.5     5     4     6
2.5     0     3     9

I don't want to plot the first column. I manage to change the value of it.
In this example I can change the sign because all the points are superior or
equal to 0.

-0.5     6     1     1
-1.5     5     4     6
-2.5     0     3     9

Then the 'splot' query would look like this:

splot 'example.dat' matrix using 1:2:($3<0 ? 1/0 : $3)

Because 1/0 is undefined the terms inferior to 0, i.e., the 1st column,
gnuplot will ignore these points.

If someone knows a smarter solution, I'm a taker!

gnuplot rules!

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