Hello everyone,
I have two data.frames that look like
calib:
place zoom scale
left 0.65 8
left 0.80 5.6
left 1.20 3
right 0.65 8.4
right 0.80 6
right 1.20 2.9
X:
... place zoom ....
... left 0.80 ....
... left 1.20 ....
... right 0.65 ....
... NA NA ....
... right 0.8 ....
... left 1.20 ....
and I want to get the corresponding values of 'scale' in a new column
in X, i.e.:
X:
... place zoom .... scale
... left 0.80 .... 5.6
... left 1.20 .... 3
... right 0.65 .... 8.4
... NA NA .... NA
... right 0.8 .... 6
... left 1.20 .... 3
I tried various combination of `which` and `match` but could not make
it work.
I fell back on defining a custom function and applying it over the lines
get.scales <- function(x)
{
if (is.na(x$zoom)) {
scaleF = NA
} else {
scaleF = calib[calib$zoom==x$zoom &
calib$place==x$place, "scale"]
}
return(scaleF)
}
and
apply(X, 1, get.scales)
but:
- this is not very practical since using apply apparently converts the
data to an array and looses column titles (i.e. x$size does not work,
I need to use column numbers, which I'd rather not)
- I feel there is an easier, vector based way.
I would welcome suggestions. Thank you in advance.
JiHO
---
http://jo.irisson.free.fr/
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