Does R have a wildcard expression (such as an asterisk (*))?

Question

I hope I am not missing something obvious but here is my question:

Given data like this

Data1=
Name       Number
AndyBullxxx    12
AlexPullxcx    14
AndyPamxvb     56
RickRalldfg    34
AndyPantert    45
SamSaltedf     45

I would like to be able to pull out all of the rows starting with "Andy"

subset(Data1,Name=="Andy*")

AndyBullxxx  12
AndyPamxvb   56
AndyPantert  45

So basically a wild card symbol that will let me subset all rows that begin with a certain character designation.

Answer 1

Try,

df[grep("^Andy",rownames(df)),]

the first argument of grep is a pattern, a regular expression. grep gives back the rows that contain the pattern given in this first argument. the ^ means beginning with.

Let's make this reproducible:

 df <- data.frame(x=c(12,14,56,34,45,45))
 rownames(df) <- c("AndyBullxxx", "AlexPullxcx","AndyPamxvb", "RickRalldfg","AndyPantert","SamSaltedf")
 ## see what grep does
 grep("^Andy",rownames(df))