Count the values of a column based on the values of another column in R

December 22, 2021

Using the dataframe I want to create a new one which will contain Zip, Name and a column named Count which will include the count of Name per Zip.

Zip<-c("123245","12345","123245","123456","123456","12345")
Name<-c("Bob","Bob","Bob","Jack","Jack","Mary")
df<-data.frame(Zip,Name)

library(dplyr)
df %>%
  group_by(Zip) %>%
  mutate(Name = cumsum(Name))

expected

Zip Name Count
1 123245  Bob     2
2  12345  Bob     1
3  12345 Mary     1
4 123456 Jack     2

>Solution :

Does this solve your problem?

Zip<-c("123245","12345","123245","123456","123456","12345")
Name<-c("Bob","Bob","Bob","Jack","Jack","Mary")
df<-data.frame(Zip,Name)

library(dplyr)
#> 
#> Attaching package: 'dplyr'
#> The following objects are masked from 'package:stats':
#> 
#>     filter, lag
#> The following objects are masked from 'package:base':
#> 
#>     intersect, setdiff, setequal, union
df %>%
  group_by(Zip, Name) %>%
  summarise(Count = n())
#> `summarise()` has grouped output by 'Zip'. You can override using the `.groups` argument.
#> # A tibble: 4 × 3
#> # Groups:   Zip [3]
#>   Zip    Name  Count
#>   <chr>  <chr> <int>
#> 1 123245 Bob       2
#> 2 12345  Bob       1
#> 3 12345  Mary      1
#> 4 123456 Jack      2

^{Created on 2021-12-22 by the reprex package (v2.0.1)}