CODEWITHSUNDEEP
r
Barnaby
Barnaby

Reputation: 1480

Replace a column data with another column of data in a data frame while replacing prior instances <0 by 0

I have a data frame 

x<-c(1,3,0,2,4,5,0,-2,-5,1,0)
y<-c(-1,-2,0,3,4,5,1,8,1,0,2)

data.frame(x,y)
    x  y
1   1 -1
2   3 -2
3   0  0
4   2  3
5   4  4
6   5  5
7   0  1
8  -2  8
9  -5  1
10  1  0
11  0  2

I would like to replace the data in column y with data from column x and also replacing in y the instances that where <0 in y and replacing them by 0. This will result in the following data frame

data.frame(x,y)
    x  y
1   1  0
2   3  0
3   0  0
4   2  2
5   4  4
6   5  5
7   0  0
8  -2 -2
9  -5 -5
10  1  0
11  0  0

Thanks

Upvotes: 0

Views: 66

Answers (3)

janos
janos

Reputation: 124646

Given your x and y vectors, create the data.frame in one swift move:

> data.frame(x, y=ifelse(y < 0, 0, x))
    x  y
1   1  0
2   3  0
3   0  0
4   2  2
5   4  4
6   5  5
7   0  0
8  -2 -2
9  -5 -5
10  1  1
11  0  0

Upvotes: 1

datawookie
datawookie

Reputation: 6534

In one line:

> df <- transform(data.frame(x,y), y = ifelse(y<0,0,x))
> df
    x  y
1   1  0
2   3  0
3   0  0
4   2  2
5   4  4
6   5  5
7   0  0
8  -2 -2
9  -5 -5
10  1  1
11  0  0

Note that the resulting data differs from the reference result you provide on record 10. I suspect that this might be because you applied the condition <= 0 rather than < 0? Otherwise the 1 would be carried across from the x field for this record.

Upvotes: 1

lukeA
lukeA

Reputation: 54237

x<-c(1,3,0,2,4,5,0,-2,-5,1,0)
y<-c(-1,-2,0,3,4,5,1,8,1,0,2)
df <- data.frame(x, y)
df$y <- ifelse(y<0,0,x)
df
#     x  y
# 1   1  0
# 2   3  0
# 3   0  0
# 4   2  2
# 5   4  4
# 6   5  5
# 7   0  0
# 8  -2 -2
# 9  -5 -5
# 10  1  1
# 11  0  0

Upvotes: 2

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