如何使用gnuplot绘制数据文件中的特定数据子集? [英] How to plot a specific subset of data from a data file with gnuplot?

问题描述

我需要从数据文件中的一行绘制一个点，该点具有许多其他行和两行.我不知道如何在gnuplot中选择一行，而不是整个数据文件.有任何建议吗?

I need to plot a single point, from a line in data file, that has many other lines and two rows. I don't know how to select a single line in gnuplot, not the entire file of data. Any suggestions please???

推荐答案

如果要绘制的点不是以行号为特征，而是以一列中的某个值为特征，则可以在using:

In case the point(s) you want to plot are not characterized by the line number, but by some value in one column, you can use this trick in using :

plot '-' using (($1==0)?$1:1/0):2 with points
-1 1
0  2
1  3
e

这可以用来绘制例如仅使用x坐标为正的点(更改为($1>=0)?$1:1/0)，或者使用包含行号的$0伪列，以比every更通用的方式选择特定的行:

This can be used to plot e.g. only points with a positive x-coordinate (change to ($1>=0)?$1:1/0), or also, using the $0 pseudo-column which contains the line number, to select specific lines in a more versatile way than every :

plot 'data.dat' using (((int($0)%3!=0)?$1:1/0):2 with points

这里我们从3条图中绘制了2条线，当然，您也可以仅使用($0==LINE)?$1:1/0选择一条线.

Here we plot 2 lines out of 3, of course you can also select one line only with ($0==LINE)?$1:1/0.

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