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Update for new cross_join() function

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Hadley Wickham
2022-12-18 10:18:49 -06:00
parent 35f9c847b7
commit ca75b0c02a
1 changed files with 2 additions and 1 deletions
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joins.qmd
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@@ -783,10 +783,11 @@ knitr::include_graphics("diagrams/join/cross.png", dpi = 270)
Cross joins are useful when generating permutations. Cross joins are useful when generating permutations.
For example, the code below generates every possible pair of names. For example, the code below generates every possible pair of names.
Since we're joining `df` to itself, this is sometimes called a **self-join**. Since we're joining `df` to itself, this is sometimes called a **self-join**.
Cross joins use a different join function because there's no distinction between inner/left/right/full when you're matching every row.
```{r} ```{r}
df <- tibble(name = c("John", "Simon", "Tracy", "Max")) df <- tibble(name = c("John", "Simon", "Tracy", "Max"))
df |> left_join(df, join_by()) df |> cross_join(df)
``` ```
### Inequality joins ### Inequality joins