# r用法 - 如何從R data.frame獲取行

## r plot legend (3)

``````> d <- data.frame(a=1:3, b=4:6, c=7:9)

> d
a b c
1 1 4 7
2 2 5 8
3 3 6 9

> d[1, ]
a b c
1 1 4 7

> d[1, ]['a']
a
1 1
``````

```      A    B    C
1 5    4.25 4.5
2 3.5  4    2.5
3 3.25 4    4
4 4.25 4.5  2.25
5 1.5  4.5  3
```

``````> c(a=5, b=4.25, c=4.5)
a   b   c
5.0 4.25 4.5
``````

``````x <- structure(list(A = c(5,    3.5, 3.25, 4.25,  1.5 ),
B = c(4.25, 4,   4,    4.5,   4.5 ),
C = c(4.5,  2.5, 4,    2.25,  3   )
),
.Names    = c("A", "B", "C"),
class     = "data.frame",
row.names = c(NA, -5L)
)

subset(x, A ==5 & B==4.25 & C==4.5)
``````

``````x[r,]
``````

``````#Add your data
x <- structure(list(A = c(5,    3.5, 3.25, 4.25,  1.5 ),
B = c(4.25, 4,   4,    4.5,   4.5 ),
C = c(4.5,  2.5, 4,    2.25,  3   )
),
.Names    = c("A", "B", "C"),
class     = "data.frame",
row.names = c(NA, -5L)
)

#The vector your result should match
y<-c(A=5, B=4.25, C=4.5)

#Test that the items in the row match the vector you wanted
x[1,]==y
``````