Once a table is uploaded in R, how would you dynamically capture columns from a user and then remove these columns from the table uploaded?
Hi!
You can read an input from command line with the function readline():
> col col
[1] "5"
It saves the value as a character that you can easily convert in integer with as.integer col data[,col]=NULL
I hope it can be helpful!
Valentina
Hi!
You can read an input from command line with the function readline():
> col col
[1] "5"
It saves the value as a character that you can easily convert in integer with as.integer col data[,col]=NULL
I hope it can be helpful!
Valentina
Thanks Valentina...
However, I got an error after using the readline() and converting to an integer...
data[,col]=NULL
Error in data[, col] = NULL : object of type 'closure' is not subsettable
Any suggestions...
I tried with a little dataset and it works for me, I paste the entire code:
data=read.table(text="
col1 col2
a b
c d
e f",header=TRUE)
> data
col1 col2
1 a b
2 c d
3 e f
> col=readline("ENTER COLUMN: ")
ENTER COLUMN: 1
> col=as.integer(col)
> data[,col]=NULL
> data
col2
1 b
2 d
3 f
It gives me no errors.
From this answer http://stackoverflow.com/questions/11308367/error-in-my-code-object-of-type-closure-is-not-subsettable it seems that your problem is: "In general this error message means that you have tried to use indexing on a function"
Thanks Valentina and you are right - it works for one column.
However, when I tried to remove more than 1 column I get an error - how would you handle more than 1 column?
You can easily delete more than one column like this:
data=data.frame(col1=c("a","b","c"),col2=c("d","f","g"),col3=c(1,2,3), col4=c(4,5,6))
> data
col1 col2 col3 col4
1 a d 1 4
2 b f 2 5
3 c g 3 6
> data[,-c(1,2)]
col3 col4
1 1 4
2 2 5
3 3 6
in this way you delete the first and second column but of course, you can pass all the values and variables you want
Thanks Valentina...
but, is there a way that I can store more than one character/integer in: col
> col col
[1] "1 2 3 4"
> as.integer(unlist(strsplit(col, " ")))
[1] 1 2 3 4
You obtain a vector of integers that you can use to subset your dataframe.
Thanks Valentina once again.
Im subsetting a dataframe with no headings (so, names=var1, var2, etc..) and tried using the following to subset and delete the columns : dat
Perhaps there is an easier way of doing this, but this is what worked (since there is no headings in the dataframe, use var1, var2, var3, etc... when asked for values):
col
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