CODEWITHSUNDEEP
r
peter_c
peter_c

Reputation: 49

Create a new column containing the total amount of occurrences of a string in R

I would like to assign a value in a new column (i.e.: country_count) of the amount of times a specific string occurs (in total) in my data frame.

country = c("DE", "FR", "FR", "FR", "NL","DE")
data_frame =data.frame(country)

This would be the resulting data frame.

country = c("DE", "FR", "FR", "FR", "NL","DE")
country_count = c(2, 3, 3, 3, 1,2)
data_frame =data.frame(country,country_count)

I am aware that I can simply run table(data_frame$country) to get the same result, but I would like to have the values in an additional column because ultimately I want to assign a different value to the strings (in my case countries) below a certain threshold.

Upvotes: 2

Views: 422

Answers (4)

akrun
akrun

Reputation: 887951

We can use

library(data.table)
setDT(data_frame)[, country_count := .N, country]

Or using base R

data_frame$country_count <- with(data_frame, ave(seq_along(country), country, FUN = length))

Upvotes: 2

Tim
Tim

Reputation: 737

You can subset the table() result with your vector of country codes, then cast it to a data frame.

country = c("DE", "FR", "FR", "FR", "NL","DE")
as.data.frame(table(country)[country])

# Result
#  country Freq
#1      DE    2
#2      FR    3
#3      FR    3
#4      FR    3
#5      NL    1
#6      DE    2

Upvotes: 3

ktiu
ktiu

Reputation: 2636

Fairly straightforward option:

dplyr::count(data_frame, country)

Returns:

  country n
1      DE 2
2      FR 3
3      NL 1

Upvotes: 2

Martin Gal
Martin Gal

Reputation: 16998

You could use dplyr:

library(dplyr)
data_frame %>%
  add_count(country, name="country_count")

returns

  country country_count
1      DE             2
2      FR             3
3      FR             3
4      FR             3
5      NL             1
6      DE             2

Upvotes: 5

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