gather with multiple keys

Question

I know this question has been asked before, but I don't quite understand.

I have a dataset that looks like this:

Precinct  Crime       2000   2001  2002  2003  
1         Murder       3      1     2     2
1         Rape         12     5     10    11
1         Burglary     252   188    297   403
2         Murder       4      2      1     0

with the values of each crime listed under the year.

I'm trying to rearrange it into simpler sets that look like this:

Precinct    Crime    Year   Value
   1        Murder   2000     3
   1        Rape     2000     12

How do I go about doing that? I know I should be using tidyr's gather, but extrapolating solutions for multiple keys isn't working for me.

> exact duplicate of an existing question This is not exactly the same if worded differently. It is actually the opposite. He wasn't to go from a wide format to a wide format. Which can be done with tiddy:gather. — mtelesha, Nov 16 '17 at 17:38

score 11 · Accepted Answer · answered Jan 27 '17 at 15:19

11

The following works:

df %>% gather(Year, Value, -Precinct, -Crime)

answered Jan 27 '17 at 15:19

Konrad Rudolph

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2

Bizarre: why was this perfectly working, best-practice answer downvoted? – Konrad Rudolph Jan 30 '17 at 11:21

score 2 · Answer 2 · answered Jan 27 '17 at 15:22

2

You need to specify all columns that should be gathers (or remove all columns that should _not_be gathered):

library(tidyverse)

dat <- tibble::tibble(
  Precinct = c(1, 1, 1, 2),
  Crime = c("Murder", "Rape", "Burglary", "Murder"),
  `2000` = c(3, 12, 252, 4),
  `2001` = c(1, 5, 188, 2),
  `2002` = c(2, 10, 297, 1),
  `2003` = c(2, 11, 403, 0)
)

tidyr::gather(dat, Year, Value, 3:6)
tidyr::gather(dat, Year, Value, -Precinct, -Crime)

answered Jan 27 '17 at 15:22

Daniel

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Damn, I was too slow! – Daniel Jan 27 '17 at 15:23
2

yes. No point in keeping it right? – Sotos Jan 27 '17 at 15:27

gather with multiple keys

2 Answers2