CODEWITHSUNDEEP
r
stats_noob
stats_noob

Reputation: 5935

R: Meaning of "\" in Sapply?

I have a dataset that looks something like this:

name = c("john", "john", "john", "alex","alex", "tim", "tim", "tim", "ralph", "ralph")
year = c(2010, 2011, 2012, 2011, 2012, 2010, 2011, 2012, 2014, 2016)
my_data = data.frame(name, year)

    name year
1   john 2010
2   john 2011
3   john 2012
4   alex 2011
5   alex 2012
6    tim 2010
7    tim 2011
8    tim 2012
9  ralph 2014
10 ralph 2016

I am trying to count the "number of rows with at least one missing (i.e. non-consecutive) year", for example:

# sample output

              year count
1       2014, 2016     1

In a previous question (Counting Number of Unique Column Values Per Group), I received an answer - but when I tried to apply this answer, I got the following error:

agg <- aggregate(year ~ name, my_data, c)
agg <- agg$year[sapply(agg$year, \(y) any(diff(y) != 1))]
as.data.frame(table(sapply(agg, paste, collapse = ", ")))

Error: unexpected input .... " ... \"

I think this error might be due to the fact that I am using an older version of R.

Does anyone know if an alternate symbol can be used to replace "" in R that is supported by older versions of R?

Thanks!

Upvotes: 1

Views: 72

Answers (1)

akrun
akrun

Reputation: 887881

In tidyverse, we may do this as

library(dplyr)
my_data %>% 
 group_by(name) %>% 
 filter(any(diff(year) != 1)) %>%
 summarise(year = toString(year)) %>%
 count(year, name = 'count')

-output

# A tibble: 1 × 2
  year       count
  <chr>      <int>
1 2014, 2016     1

The error in OP's code is based on the R version. The lambda concise option (\(x) -> function(x)) is introduced only recently from versions R > 4.0

Upvotes: 3

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