On 14/02/14 10:46, e-letter wrote:
Readers,
A csv file was created:
column1,column2,column3,column4
1,10,3,2
2,20,6,4
3,30,12,16
4,40,24,256
The csv was imported:
testcsv<-read.csv('/path/to/test.csv')
testsum<-testcsv[2,2]+testcsv[2,3]+testcsv[2,4]
What is the correct syntax to abbreviate the following command using
the function 'with', to avoid repetitive use of the declaration
'testcsv'? Tried the following, but received the error shown:
with(testcsv,testsum<-[2,2]+[2,3]+[2,4])
Error: unexpected '[' in "with(testcsv,testsum<-["
and:
with(testcsv,{testsum<-[2,2]+[2,3]+[2,4]})
Error: unexpected '[' in "with(testcsv,{testsum<-["
What you've written is simply not (anything like!) R syntax. You should
learn to speak R if you are going to use R.
In this particular instance
testsum <- sum(testcsv[2,2:4])
should give what you want. The use of with() is uncalled for in this
context. The with() function allows you to refer to (e.g.) columns of
a data frame by name, as if these columns were objects in your workspace
("global environment"). That is *not* what you are doing, or need to do
here.
cheers,
Rolf Turner
P. S.: Please read fortune("people who don't exist") and change your
modus operandi.
R. T.
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