From 8bc81d71b116f9054a9e2d8a1799e58ddbd16b0c Mon Sep 17 00:00:00 2001 From: S'busiso Mkhondwane Date: Mon, 15 Aug 2016 14:33:36 +0200 Subject: [PATCH] Update relational-data.Rmd (#255) Typo --- relational-data.Rmd | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/relational-data.Rmd b/relational-data.Rmd index 68757d0..998b96a 100644 --- a/relational-data.Rmd +++ b/relational-data.Rmd @@ -16,7 +16,7 @@ To work with relational data you need verbs that work with pairs of tables. Ther * __Set operations__, which treat observations as if they were set elements. -The most common place to find relational data is in a _relational_ database management system (or RDBMS), a term that encompasses almost all modern databases. If you've used a database before, you've almost certainly used SQL. If so, you should find the concepts in this chapter familiar, although their expression in dplyr is a little different. Generally, dplyr is a little easier to use than SQL because dplyr is specialised to data analysis: it makes common data analysis operations easier, at the expense of making it more difficult to do other things that don't commonly need for data analysis. +The most common place to find relational data is in a _relational_ database management system (or RDBMS), a term that encompasses almost all modern databases. If you've used a database before, you've almost certainly used SQL. If so, you should find the concepts in this chapter familiar, although their expression in dplyr is a little different. Generally, dplyr is a little easier to use than SQL because dplyr is specialised to do data analysis: it makes common data analysis operations easier, at the expense of making it more difficult to do other things that don't commonly need for data analysis. ### Prerequisites @@ -176,7 +176,7 @@ flights2 <- flights %>% flights2 ``` -(Remember, when you're in RStudio, you can also use `View()` to avoid this problem). +(Remember, when you're in RStudio, you can also use `View()` to avoid this problem.) Imagine you want to add the full airline name to the `flights2` data. You can combine the `airlines` and `flights2` data frames with `left_join()`: @@ -186,7 +186,7 @@ flights2 %>% left_join(airlines, by = "carrier") ``` -The result of joining airlines to flights is an additional variable: `name`. This is why I call this type of join a mutating join. In this case, you could have got to the same place using `mutate()` and R's base subsetting: +The result of joining airlines to flights2 is an additional variable: `name`. This is why I call this type of join a mutating join. In this case, you could have got to the same place using `mutate()` and R's base subsetting: ```{r} flights2 %>%