Sent from my phone. Please excuse my brevity.
On February 20, 2017 6:53:29 PM PST, C W <tmrsg11 at gmail.com> wrote:
>Thanks Hadley!
>
>While I got your attention, what is a good way to get started on
>ggplot2? ;)
>
>My impression is that I first need to learn plyr, dplyr, AND THEN
>ggplot2.
>That's A LOT!
>
>Suppose i have this:
>iris
>iris2 <- cbind(iris, grade = sample(1:5, 150, replace = TRUE))
>iris2
>
>I want to have some kind of graph conditioned on species, by grade .
>What's
>a good lead to learn about plotting this?
>
>Thank you!
>
>
>
>On Mon, Feb 20, 2017 at 11:12 AM, Hadley Wickham <h.wickham at gmail.com>
>wrote:
>
>> On Sun, Feb 19, 2017 at 3:01 PM, David Winsemius
><dwinsemius at comcast.net>
>> wrote:
>> >
>> >> On Feb 19, 2017, at 11:37 AM, C W <tmrsg11 at gmail.com> wrote:
>> >>
>> >> Hi R,
>> >>
>> >> I am a little confused by the data.table package.
>> >>
>> >> library(data.table)
>> >>
>> >> df <- data.frame(w=rnorm(20, -10, 1), x= rnorm(20, 0, 1),
>y=rnorm(20,
>> 10, 1),
>> >> z=rnorm(20, 20, 1))
>> >>
>> >> df <- data.table(df)
>> >
>> > df <- setDT(df) is preferred.
>>
>> Don't you mean just
>>
>> setDT(df)
>>
>> ?
>>
>> setDT() modifies by reference.
>>
>> >>
>> >> df_3 <- df[, a := x-y] # created new column a using x minus y, why
>are
>> we
>> >> using colon equals?
>> >
>> > You need to do more study of the extensive documentation. The
>behavior
>> of the ":=" function is discussed in detail there.
>>
>> You can get to that documentation with ?":="
>>
>> Hadley
>>
>> --
>> http://hadley.nz
>>
>
> [[alternative HTML version deleted]]
>
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