Applying ifelse function to transform entire column in data frame
0
I have a data frame such as this:
df <- data.frame(x = c("A", "B", "C", "D"),
y = c(-1, -2, 3, 1))
And I want to multiply the values of df$y by -1 if the value of A is less than 0, as is the case here. So instead of being (-1, -2, 3, 1), it becomes (1, 2, -3, -1).
The closest I've gotten is this:
df$y <- ifelse(df[df$x == "A", 2] < 0, df$y*-1, df$y)
Thanks!
r dataframe if-statement grepl
asked Nov 25 '18 at 17:32
Marco Pastor MayoMarco Pastor Mayo
767
add a comment |
0
I have a data frame such as this:
df <- data.frame(x = c("A", "B", "C", "D"),
y = c(-1, -2, 3, 1))
And I want to multiply the values of df$y by -1 if the value of A is less than 0, as is the case here. So instead of being (-1, -2, 3, 1), it becomes (1, 2, -3, -1).
The closest I've gotten is this:
df$y <- ifelse(df[df$x == "A", 2] < 0, df$y*-1, df$y)
Thanks!
r dataframe if-statement grepl
asked Nov 25 '18 at 17:32
Marco Pastor MayoMarco Pastor Mayo
767
1
Your problem description doesn't match the posted expected output. In that output you multiply the entire columnyby-1, without considering the value of columnx.
– Rui Barradas
Nov 25 '18 at 17:46
add a comment |
0
0
0
I have a data frame such as this:
df <- data.frame(x = c("A", "B", "C", "D"),
y = c(-1, -2, 3, 1))
And I want to multiply the values of df$y by -1 if the value of A is less than 0, as is the case here. So instead of being (-1, -2, 3, 1), it becomes (1, 2, -3, -1).
The closest I've gotten is this:
df$y <- ifelse(df[df$x == "A", 2] < 0, df$y*-1, df$y)
Thanks!
r dataframe if-statement grepl
asked Nov 25 '18 at 17:32
Marco Pastor MayoMarco Pastor Mayo
767
I have a data frame such as this:
df <- data.frame(x = c("A", "B", "C", "D"),
y = c(-1, -2, 3, 1))
And I want to multiply the values of df$y by -1 if the value of A is less than 0, as is the case here. So instead of being (-1, -2, 3, 1), it becomes (1, 2, -3, -1).
The closest I've gotten is this:
df$y <- ifelse(df[df$x == "A", 2] < 0, df$y*-1, df$y)
Thanks!
r dataframe if-statement grepl
r dataframe if-statement grepl
asked Nov 25 '18 at 17:32
Marco Pastor MayoMarco Pastor Mayo
767
asked Nov 25 '18 at 17:32
Marco Pastor MayoMarco Pastor Mayo
767
asked Nov 25 '18 at 17:32
Marco Pastor MayoMarco Pastor Mayo
767
asked Nov 25 '18 at 17:32
Marco Pastor MayoMarco Pastor Mayo
767
asked Nov 25 '18 at 17:32
Marco Pastor MayoMarco Pastor Mayo
767
767
1
Your problem description doesn't match the posted expected output. In that output you multiply the entire columnyby-1, without considering the value of columnx.
– Rui Barradas
Nov 25 '18 at 17:46
add a comment |
1
Your problem description doesn't match the posted expected output. In that output you multiply the entire columnyby-1, without considering the value of columnx.
– Rui Barradas
Nov 25 '18 at 17:46
1
1
Your problem description doesn't match the posted expected output. In that output you multiply the entire column
y by -1, without considering the value of column x.– Rui Barradas
Nov 25 '18 at 17:46
Your problem description doesn't match the posted expected output. In that output you multiply the entire column
y by -1, without considering the value of column x.– Rui Barradas
Nov 25 '18 at 17:46
add a comment |
1 Answer
1
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oldest
votes
2
You could just do:
df$y <- ifelse(df$x == "A" & df$y < 0, df$y * -1, df$y)
If you want to multiply all, then something like:
df$y <- if (any(df$x == "A" & df$y < 0)) df$y * -1 else df$y
answered Nov 25 '18 at 17:36
arg0nautarg0naut
5,7641421
This only results in flipping the value ofdf$ywhendf$x="A", but I want to flip alldf$yvalues whendf$x="A".
– Marco Pastor Mayo
Nov 26 '18 at 15:57
In that case, see my edit.
– arg0naut
Nov 26 '18 at 16:18
add a comment |
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1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
2
You could just do:
df$y <- ifelse(df$x == "A" & df$y < 0, df$y * -1, df$y)
If you want to multiply all, then something like:
df$y <- if (any(df$x == "A" & df$y < 0)) df$y * -1 else df$y
answered Nov 25 '18 at 17:36
arg0nautarg0naut
5,7641421
This only results in flipping the value ofdf$ywhendf$x="A", but I want to flip alldf$yvalues whendf$x="A".
– Marco Pastor Mayo
Nov 26 '18 at 15:57
In that case, see my edit.
– arg0naut
Nov 26 '18 at 16:18
add a comment |
2
You could just do:
df$y <- ifelse(df$x == "A" & df$y < 0, df$y * -1, df$y)
If you want to multiply all, then something like:
df$y <- if (any(df$x == "A" & df$y < 0)) df$y * -1 else df$y
answered Nov 25 '18 at 17:36
arg0nautarg0naut
5,7641421
This only results in flipping the value ofdf$ywhendf$x="A", but I want to flip alldf$yvalues whendf$x="A".
– Marco Pastor Mayo
Nov 26 '18 at 15:57
In that case, see my edit.
– arg0naut
Nov 26 '18 at 16:18
add a comment |
2
2
2
You could just do:
df$y <- ifelse(df$x == "A" & df$y < 0, df$y * -1, df$y)
If you want to multiply all, then something like:
df$y <- if (any(df$x == "A" & df$y < 0)) df$y * -1 else df$y
answered Nov 25 '18 at 17:36
arg0nautarg0naut
5,7641421
You could just do:
df$y <- ifelse(df$x == "A" & df$y < 0, df$y * -1, df$y)
If you want to multiply all, then something like:
df$y <- if (any(df$x == "A" & df$y < 0)) df$y * -1 else df$y
answered Nov 25 '18 at 17:36
arg0nautarg0naut
5,7641421
edited Nov 26 '18 at 16:18
answered Nov 25 '18 at 17:36
arg0nautarg0naut
5,7641421
answered Nov 25 '18 at 17:36
arg0nautarg0naut
5,7641421
answered Nov 25 '18 at 17:36
arg0nautarg0naut
5,7641421
5,7641421
This only results in flipping the value ofdf$ywhendf$x="A", but I want to flip alldf$yvalues whendf$x="A".
– Marco Pastor Mayo
Nov 26 '18 at 15:57
In that case, see my edit.
– arg0naut
Nov 26 '18 at 16:18
add a comment |
This only results in flipping the value ofdf$ywhendf$x="A", but I want to flip alldf$yvalues whendf$x="A".
– Marco Pastor Mayo
Nov 26 '18 at 15:57
In that case, see my edit.
– arg0naut
Nov 26 '18 at 16:18
This only results in flipping the value of
df$y when df$x="A", but I want to flip all df$y values when df$x="A".– Marco Pastor Mayo
Nov 26 '18 at 15:57
This only results in flipping the value of
df$y when df$x="A", but I want to flip all df$y values when df$x="A".– Marco Pastor Mayo
Nov 26 '18 at 15:57
In that case, see my edit.
– arg0naut
Nov 26 '18 at 16:18
In that case, see my edit.
– arg0naut
Nov 26 '18 at 16:18
add a comment |
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1
Your problem description doesn't match the posted expected output. In that output you multiply the entire column
yby-1, without considering the value of columnx.– Rui Barradas
Nov 25 '18 at 17:46