How do you find the number of unique values that span multiple columns?

Question

How do you find the number of unique values when they span multiple columns. In my case, I am trying to get a count of the number of times each latitude/longitude occurs.

For example

+------------+
|  Lat Long  |
+------------+
| 39.3 -76.6 |
| 39.3 -76.6 |
| 39.3 -76.6 |
| 39.9 -76.1 |
+------------+

Would output

+---------------+
| Lat Long Freq |
+---------------+
| 39.3 -76.6 3  |
| 39.9 -76.1 1  |
+---------------+

Your title says spanning multiple rows, but your question says columns. Also, you said number of unique values, but aren't you trying to count the opposite, i.e. the number of times a value is repeated? — camille, Jan 30 '20 at 17:57

score 1 · Answer 1 · answered Jan 30 '20 at 17:43

1

One option is to use count

library(dplyr) 
count(df1, Lat, Long)

answered Jan 30 '20 at 17:43

akrun

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score 1 · Answer 2 · answered Jan 30 '20 at 17:47

1

dplyr::summarize() should also do the trick:

df <- df %>%
   group_by(Lat,Long) %>%
   summarize(Freq = n())

answered Jan 30 '20 at 17:47

TTS

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score 1 · Accepted Answer · answered Jan 30 '20 at 17:59

1

A base R solution:

Data = data.frame(Lat = c(39.3, 39.3, 39.3, 39.9),
        Long = c(-76.6, -76.6, -76.6, -76.1))

aggregate(rep(1, nrow(Data)), Data, sum)

   Lat  Long x
1 39.3 -76.6 3
2 39.9 -76.1 1

answered Jan 30 '20 at 17:59

G5W

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All of these answers did the trick. They could all be accepted answers. – cylus Jan 31 '20 at 13:03

How do you find the number of unique values that span multiple columns?

3 Answers3