R help - Jun 2007 - determining the column index and grabbing only variables with a certain string in them

Hello!

I have a data set with almost 2,000 variables (called 'Data').
I want to select only a set of variables that have a certain string in
them (e.g., "Variable") - 'Variable.1', 'Variable.2',
etc. until
'Variable.20'.

2 questions:

1. How can I determine the exact column index of a variable in the
data frame if I know its exact name? (I am asking because names(Data)
allows me to see only the last 1,348 variables)
2. How can I grab only variables that have a string "Variable" in
their name using grep?

Thank you!
Dimitri

1. which("Exat Name" == names(Data)   ## Assuming Data is your
data.frame

2. grep("Variable", names(Data))

Xiaohui

Dimitri Liakhovitski wrote:
> Hello!
>
> I have a data set with almost 2,000 variables (called 'Data').
> I want to select only a set of variables that have a certain string in
> them (e.g., "Variable") - 'Variable.1',
'Variable.2', etc. until
> 'Variable.20'.
>
> 2 questions:
>
> 1. How can I determine the exact column index of a variable in the
> data frame if I know its exact name? (I am asking because names(Data)
> allows me to see only the last 1,348 variables)
> 2. How can I grab only variables that have a string "Variable" in
> their name using grep?
>
> Thank you!
> Dimitri
>
> ______________________________________________
> R-help at stat.math.ethz.ch mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>
>