I have a data frame (df)
and I was wondering how to return the row number(s) for a particular value (2585)
in the 4th column (height_chad1)
of the same data frame?
I've tried:
row(mydata_2$height_chad1, 2585)
and I get the following error:
Error in factor(.Internal(row(dim(x))), labels = labs) :
a matrix-like object is required as argument to 'row'
Is there an equivalent line of code that works for data frames instead of matrix-like objects?
Any help would be appreciated.
Use which(mydata_2$height_chad1 == 2585)
Short example
df <- data.frame(x = c(1,1,2,3,4,5,6,3),
y = c(5,4,6,7,8,3,2,4))
df
x y
1 1 5
2 1 4
3 2 6
4 3 7
5 4 8
6 5 3
7 6 2
8 3 4
which(df$x == 3)
[1] 4 8
length(which(df$x == 3))
[1] 2
count(df, vars = "x")
x freq
1 1 2
2 2 1
3 3 2
4 4 1
5 5 1
6 6 1
df[which(df$x == 3),]
x y
4 3 7
8 3 4
As Matt Weller pointed out, you can use the length
function.
The count
function in plyr
can be used to return the count of each unique column value.