[R] Plotting using 'if' statements
Steve Murray
smurray444 at hotmail.com
Thu Sep 4 18:28:31 CEST 2008
Dear all,
I have a dataset of four columns, and I wish to plot (as a scatter graph) the values of the third column where the values are greater than zero, and the fourth column.
I tried doing this via the plot command itself, but got into a bit of a mess (resulting in errors!). My dataframe is called 'January':
> plot(January[3(>0):4])
Error: unexpected '>' in "plot(January[3(>"
After a few variations on this, I thought I'd try making a new object which includes all values from the third column of January>0 (to plot in a separate step) as follows:
> JanFilter <- January[3]>0
No error here. However, when I display the 'values' of JanFilter, it shows that instead of keeping the numerical values, the above operation simply displays the results of the logical test:
> head(JanFilter)
Value
[1,] FALSE
[2,] TRUE
[3,] TRUE
[4,] TRUE
[5,] TRUE
[6,] TRUE
This is obviously no good for plotting the numerical values on axes!
So my question is, how do I perform 'if' statements in order to filter out various parts of a dataset, for plotting on a graph.
Many thanks,
Steve
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