What does the magrittr dot/period (“.”) operator do when it's at the very beginning of a pipeline?
I don't understand what the . in the following code is doing or where to find documentation for it:
library(tidyverse)
ggplot(iris) +
geom_point(
aes(x=Sepal.Length, y=Sepal.Width),
data = . %>% filter(Species == 'setosa')
)
This appears to be behaving quite differently from the usage described in What does the dplyr period character "." reference? where the . does not appear in the left-hand-most position.
The docs here say merely
A pipeline with a dot (.) as LHS will create a unary function. This is
used to define the aggregator function.
but this is not at all clear to me and I'm hoping for more information.
r ggplot2 magrittr
asked Nov 22 at 18:30
nicolaskruchten
13.1k64971
|
show 1 more comment
I don't understand what the . in the following code is doing or where to find documentation for it:
library(tidyverse)
ggplot(iris) +
geom_point(
aes(x=Sepal.Length, y=Sepal.Width),
data = . %>% filter(Species == 'setosa')
)
This appears to be behaving quite differently from the usage described in What does the dplyr period character "." reference? where the . does not appear in the left-hand-most position.
The docs here say merely
A pipeline with a dot (.) as LHS will create a unary function. This is
used to define the aggregator function.
but this is not at all clear to me and I'm hoping for more information.
r ggplot2 magrittr
asked Nov 22 at 18:30
nicolaskruchten
13.1k64971
It's the previous data.frame.
– Rui Barradas
Nov 22 at 18:31
I'm not sure why that would be or where the documentation is?
– nicolaskruchten
Nov 22 at 18:40
Documentation? Here we go: magrittr v1.5, vignette. Cheers
– Henrik
Nov 22 at 18:41
The only explanation in those docs is "A pipeline with a dot (.) as LHS will create a unary function. This is used to define the aggregator function." ... i was hoping for MORE information by asking this question...
– nicolaskruchten
Nov 22 at 19:11
it seems like it means that it will act likefunction(x) {x}is that right?
– nicolaskruchten
Nov 22 at 19:21
|
show 1 more comment
I don't understand what the . in the following code is doing or where to find documentation for it:
library(tidyverse)
ggplot(iris) +
geom_point(
aes(x=Sepal.Length, y=Sepal.Width),
data = . %>% filter(Species == 'setosa')
)
This appears to be behaving quite differently from the usage described in What does the dplyr period character "." reference? where the . does not appear in the left-hand-most position.
The docs here say merely
A pipeline with a dot (.) as LHS will create a unary function. This is
used to define the aggregator function.
but this is not at all clear to me and I'm hoping for more information.
r ggplot2 magrittr
asked Nov 22 at 18:30
nicolaskruchten
13.1k64971
I don't understand what the . in the following code is doing or where to find documentation for it:
library(tidyverse)
ggplot(iris) +
geom_point(
aes(x=Sepal.Length, y=Sepal.Width),
data = . %>% filter(Species == 'setosa')
)
This appears to be behaving quite differently from the usage described in What does the dplyr period character "." reference? where the . does not appear in the left-hand-most position.
The docs here say merely
A pipeline with a dot (.) as LHS will create a unary function. This is
used to define the aggregator function.
but this is not at all clear to me and I'm hoping for more information.
r ggplot2 magrittr
r ggplot2 magrittr
asked Nov 22 at 18:30
nicolaskruchten
13.1k64971
asked Nov 22 at 18:30
nicolaskruchten
13.1k64971
edited Nov 24 at 2:07
asked Nov 22 at 18:30
nicolaskruchten
13.1k64971
asked Nov 22 at 18:30
nicolaskruchten
13.1k64971
asked Nov 22 at 18:30
nicolaskruchten
13.1k64971
13.1k64971
It's the previous data.frame.
– Rui Barradas
Nov 22 at 18:31
I'm not sure why that would be or where the documentation is?
– nicolaskruchten
Nov 22 at 18:40
Documentation? Here we go: magrittr v1.5, vignette. Cheers
– Henrik
Nov 22 at 18:41
The only explanation in those docs is "A pipeline with a dot (.) as LHS will create a unary function. This is used to define the aggregator function." ... i was hoping for MORE information by asking this question...
– nicolaskruchten
Nov 22 at 19:11
it seems like it means that it will act likefunction(x) {x}is that right?
– nicolaskruchten
Nov 22 at 19:21
|
show 1 more comment
It's the previous data.frame.
– Rui Barradas
Nov 22 at 18:31
I'm not sure why that would be or where the documentation is?
– nicolaskruchten
Nov 22 at 18:40
Documentation? Here we go: magrittr v1.5, vignette. Cheers
– Henrik
Nov 22 at 18:41
The only explanation in those docs is "A pipeline with a dot (.) as LHS will create a unary function. This is used to define the aggregator function." ... i was hoping for MORE information by asking this question...
– nicolaskruchten
Nov 22 at 19:11
it seems like it means that it will act likefunction(x) {x}is that right?
– nicolaskruchten
Nov 22 at 19:21
It's the previous data.frame.
– Rui Barradas
Nov 22 at 18:31
It's the previous data.frame.
– Rui Barradas
Nov 22 at 18:31
I'm not sure why that would be or where the documentation is?
– nicolaskruchten
Nov 22 at 18:40
I'm not sure why that would be or where the documentation is?
– nicolaskruchten
Nov 22 at 18:40
Documentation? Here we go: magrittr v1.5, vignette. Cheers
– Henrik
Nov 22 at 18:41
Documentation? Here we go: magrittr v1.5, vignette. Cheers
– Henrik
Nov 22 at 18:41
The only explanation in those docs is "A pipeline with a dot (.) as LHS will create a unary function. This is used to define the aggregator function." ... i was hoping for MORE information by asking this question...
– nicolaskruchten
Nov 22 at 19:11
The only explanation in those docs is "A pipeline with a dot (.) as LHS will create a unary function. This is used to define the aggregator function." ... i was hoping for MORE information by asking this question...
– nicolaskruchten
Nov 22 at 19:11
it seems like it means that it will act like
function(x) {x} is that right?– nicolaskruchten
Nov 22 at 19:21
it seems like it means that it will act like
function(x) {x} is that right?– nicolaskruchten
Nov 22 at 19:21
|
show 1 more comment
1 Answer
1
active
oldest
votes
The confusion here can actually come from two places.
First, yes, the . %>% something() syntax creates a "unary" function that takes one argument. So:
. %>% filter(Species == 'setosa')
is equivalent to
function(.) filter(., Species == 'setosa')
The second part here is that ggplot2 layers can actually take a function as their data argument. From e.g. ?geom_point:
The data to be displayed in this layer. There are three options:
...
A function will be called with a single argument, the plot data. The return value must be a data.frame, and will be used as the layer data.
So the function that is passed to geom_point will always be applied to the default plot data (i.e. the data defined in ggplot()).
Note that your linked question concerns the use of . in funs(), which is not directly related to it's use here.
answered Nov 22 at 19:54
Axeman
18.3k44256
Thanks! So is it fair to say that the.by itself is equivalent tofunction(x){x}in this context?
– nicolaskruchten
Nov 23 at 20:41
.by itself does nothing, it's the%>%that recognizes it and does all the magic. So you really. %>% somethingas a combination for a function to be created. You can look at the source of the pipe and see it explicitly checks if the left hand side (LHS) is a placeholder (i.e..), so it is programmed as a special case.
– Axeman
Nov 23 at 21:07
ahhh that's very helpful, thank you :)
– nicolaskruchten
Nov 24 at 2:08
add a comment |
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The confusion here can actually come from two places.
First, yes, the . %>% something() syntax creates a "unary" function that takes one argument. So:
. %>% filter(Species == 'setosa')
is equivalent to
function(.) filter(., Species == 'setosa')
The second part here is that ggplot2 layers can actually take a function as their data argument. From e.g. ?geom_point:
The data to be displayed in this layer. There are three options:
...
A function will be called with a single argument, the plot data. The return value must be a data.frame, and will be used as the layer data.
So the function that is passed to geom_point will always be applied to the default plot data (i.e. the data defined in ggplot()).
Note that your linked question concerns the use of . in funs(), which is not directly related to it's use here.
answered Nov 22 at 19:54
Axeman
18.3k44256
Thanks! So is it fair to say that the.by itself is equivalent tofunction(x){x}in this context?
– nicolaskruchten
Nov 23 at 20:41
.by itself does nothing, it's the%>%that recognizes it and does all the magic. So you really. %>% somethingas a combination for a function to be created. You can look at the source of the pipe and see it explicitly checks if the left hand side (LHS) is a placeholder (i.e..), so it is programmed as a special case.
– Axeman
Nov 23 at 21:07
ahhh that's very helpful, thank you :)
– nicolaskruchten
Nov 24 at 2:08
add a comment |
The confusion here can actually come from two places.
First, yes, the . %>% something() syntax creates a "unary" function that takes one argument. So:
. %>% filter(Species == 'setosa')
is equivalent to
function(.) filter(., Species == 'setosa')
The second part here is that ggplot2 layers can actually take a function as their data argument. From e.g. ?geom_point:
The data to be displayed in this layer. There are three options:
...
A function will be called with a single argument, the plot data. The return value must be a data.frame, and will be used as the layer data.
So the function that is passed to geom_point will always be applied to the default plot data (i.e. the data defined in ggplot()).
Note that your linked question concerns the use of . in funs(), which is not directly related to it's use here.
answered Nov 22 at 19:54
Axeman
18.3k44256
Thanks! So is it fair to say that the.by itself is equivalent tofunction(x){x}in this context?
– nicolaskruchten
Nov 23 at 20:41
.by itself does nothing, it's the%>%that recognizes it and does all the magic. So you really. %>% somethingas a combination for a function to be created. You can look at the source of the pipe and see it explicitly checks if the left hand side (LHS) is a placeholder (i.e..), so it is programmed as a special case.
– Axeman
Nov 23 at 21:07
ahhh that's very helpful, thank you :)
– nicolaskruchten
Nov 24 at 2:08
add a comment |
The confusion here can actually come from two places.
First, yes, the . %>% something() syntax creates a "unary" function that takes one argument. So:
. %>% filter(Species == 'setosa')
is equivalent to
function(.) filter(., Species == 'setosa')
The second part here is that ggplot2 layers can actually take a function as their data argument. From e.g. ?geom_point:
The data to be displayed in this layer. There are three options:
...
A function will be called with a single argument, the plot data. The return value must be a data.frame, and will be used as the layer data.
So the function that is passed to geom_point will always be applied to the default plot data (i.e. the data defined in ggplot()).
Note that your linked question concerns the use of . in funs(), which is not directly related to it's use here.
answered Nov 22 at 19:54
Axeman
18.3k44256
The confusion here can actually come from two places.
First, yes, the . %>% something() syntax creates a "unary" function that takes one argument. So:
. %>% filter(Species == 'setosa')
is equivalent to
function(.) filter(., Species == 'setosa')
The second part here is that ggplot2 layers can actually take a function as their data argument. From e.g. ?geom_point:
The data to be displayed in this layer. There are three options:
...
A function will be called with a single argument, the plot data. The return value must be a data.frame, and will be used as the layer data.
So the function that is passed to geom_point will always be applied to the default plot data (i.e. the data defined in ggplot()).
Note that your linked question concerns the use of . in funs(), which is not directly related to it's use here.
answered Nov 22 at 19:54
Axeman
18.3k44256
answered Nov 22 at 19:54
Axeman
18.3k44256
answered Nov 22 at 19:54
Axeman
18.3k44256
answered Nov 22 at 19:54
Axeman
18.3k44256
18.3k44256
Thanks! So is it fair to say that the.by itself is equivalent tofunction(x){x}in this context?
– nicolaskruchten
Nov 23 at 20:41
.by itself does nothing, it's the%>%that recognizes it and does all the magic. So you really. %>% somethingas a combination for a function to be created. You can look at the source of the pipe and see it explicitly checks if the left hand side (LHS) is a placeholder (i.e..), so it is programmed as a special case.
– Axeman
Nov 23 at 21:07
ahhh that's very helpful, thank you :)
– nicolaskruchten
Nov 24 at 2:08
add a comment |
Thanks! So is it fair to say that the.by itself is equivalent tofunction(x){x}in this context?
– nicolaskruchten
Nov 23 at 20:41
.by itself does nothing, it's the%>%that recognizes it and does all the magic. So you really. %>% somethingas a combination for a function to be created. You can look at the source of the pipe and see it explicitly checks if the left hand side (LHS) is a placeholder (i.e..), so it is programmed as a special case.
– Axeman
Nov 23 at 21:07
ahhh that's very helpful, thank you :)
– nicolaskruchten
Nov 24 at 2:08
Thanks! So is it fair to say that the
. by itself is equivalent to function(x){x} in this context?– nicolaskruchten
Nov 23 at 20:41
Thanks! So is it fair to say that the
. by itself is equivalent to function(x){x} in this context?– nicolaskruchten
Nov 23 at 20:41
. by itself does nothing, it's the %>% that recognizes it and does all the magic. So you really . %>% something as a combination for a function to be created. You can look at the source of the pipe and see it explicitly checks if the left hand side (LHS) is a placeholder (i.e. .), so it is programmed as a special case.– Axeman
Nov 23 at 21:07
. by itself does nothing, it's the %>% that recognizes it and does all the magic. So you really . %>% something as a combination for a function to be created. You can look at the source of the pipe and see it explicitly checks if the left hand side (LHS) is a placeholder (i.e. .), so it is programmed as a special case.– Axeman
Nov 23 at 21:07
ahhh that's very helpful, thank you :)
– nicolaskruchten
Nov 24 at 2:08
ahhh that's very helpful, thank you :)
– nicolaskruchten
Nov 24 at 2:08
add a comment |
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It's the previous data.frame.
– Rui Barradas
Nov 22 at 18:31
I'm not sure why that would be or where the documentation is?
– nicolaskruchten
Nov 22 at 18:40
Documentation? Here we go: magrittr v1.5, vignette. Cheers
– Henrik
Nov 22 at 18:41
The only explanation in those docs is "A pipeline with a dot (.) as LHS will create a unary function. This is used to define the aggregator function." ... i was hoping for MORE information by asking this question...
– nicolaskruchten
Nov 22 at 19:11
it seems like it means that it will act like
function(x) {x}is that right?– nicolaskruchten
Nov 22 at 19:21