convert list to numeric

I would like to preface this by saying that I am new to R, so I  
would ask
that you be patient and thorough, so that I'm not completely  
clueless.  I am
trying to convert a list to numeric so that I can perform  
computations on it
(specifically mean-center the variable), but I am running into  
problems.  I
have imported the data set into "task" (data frame).  The data frame  
is made
of factors with variable names in the first row.  I am running a  
loop to set
a variable equal to a column in the data frame.  Here is an example  
of my
problem:

for (i in 1:dim(task)[2]){
predictor.loop <- c(task[i])
predictor.loop.mc <- predictor.loop - mean(predictor.loop, na.rm=T)
}

I get the following error:
Error in predictor.loop - mean(predictor.loop, na.rm = T) :
 non-numeric argument to binary operator
In addition: Warning message:
In mean.default(predictor.loop, na.rm = T) :
 argument is not numeric or logical: returning NA

The column is entirely made up of numerical data, except for the  
header,
which is a string.  My problem is that I receive an error because the
predictor.loop variable is not numerical, so I need to find a way to  
convert
it.  I tried using:
predictor.loop <- c(as.numeric(task[i]))
But I get the following error: "Error: (list) object cannot be  
coerced to
type 'double'"

If I call the variable, I can assign it to a numerical list (e.g.,  
predictor
loop <- task$variablename), but since I am assigning the variable in  
a loop,
I have to find another way as the variable name would have to change  
in each
loop iteration.  Any help would be greatly appreciated.  Thanks!
--
View this message in context: http://old.nabble.com/convert-list-to-numeric-tp26155039p26155039.html
Sent from the R help mailing list archive at Nabble.com.

I would like to preface this by saying that I am new to R, so I would ask
that you be patient and thorough, so that I'm not completely clueless. ?I am
trying to convert a list to numeric so that I can perform computations on it
(specifically mean-center the variable), but I am running into problems. ?I
have imported the data set into "task" (data frame). ?The data frame is made
of factors with variable names in the first row. ?I am running a loop to set
a variable equal to a column in the data frame. ?Here is an example of my
problem:

for (i in 1:dim(task)[2]){
predictor.loop <- c(task[i])
predictor.loop.mc <- predictor.loop - mean(predictor.loop, na.rm=T)
}

I get the following error:
Error in predictor.loop - mean(predictor.loop, na.rm = T) :
?non-numeric argument to binary operator
In addition: Warning message:
In mean.default(predictor.loop, na.rm = T) :
?argument is not numeric or logical: returning NA

The column is entirely made up of numerical data, except for the header,
which is a string. ?My problem is that I receive an error because the
predictor.loop variable is not numerical, so I need to find a way to convert
it. ?I tried using:
predictor.loop <- c(as.numeric(task[i]))
But I get the following error: "Error: (list) object cannot be coerced to
type 'double'"

If I call the variable, I can assign it to a numerical list (e.g., predictor
loop <- task$variablename), but since I am assigning the variable in a loop,
I have to find another way as the variable name would have to change in each
loop iteration. ?Any help would be greatly appreciated. ?Thanks!
--
View this message in context: http://old.nabble.com/convert-list-to-numeric-tp26155039p26155039.html
Sent from the R help mailing list archive at Nabble.com.

it appears that what you really want is to use:

task[[i]]

instead of task[i]

b

On Nov 1, 2009, at 11:04 PM, dadrivr wrote:

I would like to preface this by saying that I am new to R, so I  
would ask
that you be patient and thorough, so that I'm not completely  
clueless.  I am
trying to convert a list to numeric so that I can perform  
computations on it
(specifically mean-center the variable), but I am running into  
problems.  I
have imported the data set into "task" (data frame).  The data frame  
is made
of factors with variable names in the first row.  I am running a  
loop to set
a variable equal to a column in the data frame.  Here is an example  
of my
problem:

for (i in 1:dim(task)[2]){
predictor.loop <- c(task[i])
predictor.loop.mc <- predictor.loop - mean(predictor.loop, na.rm=T)
}

I get the following error:
Error in predictor.loop - mean(predictor.loop, na.rm = T) :
 non-numeric argument to binary operator
In addition: Warning message:
In mean.default(predictor.loop, na.rm = T) :
 argument is not numeric or logical: returning NA

The column is entirely made up of numerical data, except for the  
header,
which is a string.  My problem is that I receive an error because the
predictor.loop variable is not numerical, so I need to find a way to  
convert
it.  I tried using:
predictor.loop <- c(as.numeric(task[i]))
But I get the following error: "Error: (list) object cannot be  
coerced to
type 'double'"

If I call the variable, I can assign it to a numerical list (e.g.,  
predictor
loop <- task$variablename), but since I am assigning the variable in  
a loop,
I have to find another way as the variable name would have to change  
in each
loop iteration.  Any help would be greatly appreciated.  Thanks!
--
View this message in context:
http://old.nabble.com/convert-list-to-numeric-tp26155039p26155039.html
Sent from the R help mailing list archive at Nabble.com.

Great, that works very well.  What is the purpose of double brackets vs
single ones?  I will remember next time to include a subset of the data, so
that readers can run the script.  Thanks again for your help!
 

Benilton Carvalho wrote:

it appears that what you really want is to use:

task[[i]]

instead of task[i]

b

On Nov 1, 2009, at 11:04 PM, dadrivr wrote:

I would like to preface this by saying that I am new to R, so I  
would ask
that you be patient and thorough, so that I'm not completely  
clueless.  I am
trying to convert a list to numeric so that I can perform  
computations on it
(specifically mean-center the variable), but I am running into  
problems.  I
have imported the data set into "task" (data frame).  The data frame  
is made
of factors with variable names in the first row.  I am running a  
loop to set
a variable equal to a column in the data frame.  Here is an example  
of my
problem:

for (i in 1:dim(task)[2]){
predictor.loop <- c(task[i])
predictor.loop.mc <- predictor.loop - mean(predictor.loop, na.rm=T)
}

I get the following error:
Error in predictor.loop - mean(predictor.loop, na.rm = T) :
 non-numeric argument to binary operator
In addition: Warning message:
In mean.default(predictor.loop, na.rm = T) :
 argument is not numeric or logical: returning NA

The column is entirely made up of numerical data, except for the  
header,
which is a string.  My problem is that I receive an error because the
predictor.loop variable is not numerical, so I need to find a way to  
convert
it.  I tried using:
predictor.loop <- c(as.numeric(task[i]))
But I get the following error: "Error: (list) object cannot be  
coerced to
type 'double'"

If I call the variable, I can assign it to a numerical list (e.g.,  
predictor
loop <- task$variablename), but since I am assigning the variable in  
a loop,
I have to find another way as the variable name would have to change  
in each
loop iteration.  Any help would be greatly appreciated.  Thanks!
--
View this message in context:
http://old.nabble.com/convert-list-to-numeric-tp26155039p26155039.html
Sent from the R help mailing list archive at Nabble.com.

Great, that works very well.  What is the purpose of double brackets vs
single ones?  I will remember next time to include a subset of the data, so
that readers can run the script.  Thanks again for your help!
 

Benilton Carvalho wrote:

it appears that what you really want is to use:

task[[i]]

instead of task[i]

b

On Nov 1, 2009, at 11:04 PM, dadrivr wrote:

I would like to preface this by saying that I am new to R, so I  
would ask
that you be patient and thorough, so that I'm not completely  
clueless.  I am
trying to convert a list to numeric so that I can perform  
computations on it
(specifically mean-center the variable), but I am running into  
problems.  I
have imported the data set into "task" (data frame).  The data frame  
is made
of factors with variable names in the first row.  I am running a  
loop to set
a variable equal to a column in the data frame.  Here is an example  
of my
problem:

for (i in 1:dim(task)[2]){
predictor.loop <- c(task[i])
predictor.loop.mc <- predictor.loop - mean(predictor.loop, na.rm=T)
}

I get the following error:
Error in predictor.loop - mean(predictor.loop, na.rm = T) :
 non-numeric argument to binary operator
In addition: Warning message:
In mean.default(predictor.loop, na.rm = T) :
 argument is not numeric or logical: returning NA

The column is entirely made up of numerical data, except for the  
header,
which is a string.  My problem is that I receive an error because the
predictor.loop variable is not numerical, so I need to find a way to  
convert
it.  I tried using:
predictor.loop <- c(as.numeric(task[i]))
But I get the following error: "Error: (list) object cannot be  
coerced to
type 'double'"

If I call the variable, I can assign it to a numerical list (e.g.,  
predictor
loop <- task$variablename), but since I am assigning the variable in  
a loop,
I have to find another way as the variable name would have to change  
in each
loop iteration.  Any help would be greatly appreciated.  Thanks!
--
View this message in context:
http://old.nabble.com/convert-list-to-numeric-tp26155039p26155039.html
Sent from the R help mailing list archive at Nabble.com.

 xl <- list( a=1:3, b=2:7, c=c('X','Y'))
 xl

 xl[1]

 xl[[1]]

 xl[c(1,3)]

 xd <- data.frame( a=1:3, b=2:4, c=c('X','Y','Z'))
 xd

 class(xd)

 xd[2]

 class(xd[2])

 xd[[2]]

 class(xd[[2]])

Great, that works very well.  What is the purpose of double brackets vs
single ones?  I will remember next time to include a subset of the data, so
that readers can run the script.  Thanks again for your help!


Benilton Carvalho wrote:

 it appears that what you really want is to use:

 task[[i]]

 instead of task[i]

 b

 On Nov 1, 2009, at 11:04 PM, dadrivr wrote:

 I would like to preface this by saying that I am new to R, so I 
 would ask
 that you be patient and thorough, so that I'm not completely 
 clueless.  I am
 trying to convert a list to numeric so that I can perform 
 computations on it
 (specifically mean-center the variable), but I am running into 
 problems.  I
 have imported the data set into "task" (data frame).  The data frame 
 is made
 of factors with variable names in the first row.  I am running a 
 loop to set
 a variable equal to a column in the data frame.  Here is an example 
 of my
 problem:

 for (i in 1:dim(task)[2]){
 predictor.loop <- c(task[i])
 predictor.loop.mc <- predictor.loop - mean(predictor.loop, na.rm=T)
 }

 I get the following error:
 Error in predictor.loop - mean(predictor.loop, na.rm = T) :
  non-numeric argument to binary operator
 In addition: Warning message:
 In mean.default(predictor.loop, na.rm = T) :
  argument is not numeric or logical: returning NA

 The column is entirely made up of numerical data, except for the 
 header,
 which is a string.  My problem is that I receive an error because the
 predictor.loop variable is not numerical, so I need to find a way to 
 convert
 it.  I tried using:
 predictor.loop <- c(as.numeric(task[i]))
 But I get the following error: "Error: (list) object cannot be 
 coerced to
 type 'double'"

 If I call the variable, I can assign it to a numerical list (e.g., 
 predictor
 loop <- task$variablename), but since I am assigning the variable in 
 a loop,
 >> I have to find another way as the variable name would have to change
 >> in each
 >> loop iteration.  Any help would be greatly appreciated.  Thanks!
 >> --
 >> View this message in context:
 >> http://*old.nabble.com/convert-list-to-numeric-tp26155039p26155039.html
 Sent from the R help mailing list archive at Nabble.com.

--
View this message in context: 
http://*old.nabble.com/convert-list-to-numeric-tp26155039p26157105.html
Sent from the R help mailing list archive at Nabble.com.