Countif in R programming

Question

i have a data frame with the following columns

Vendor	Product	Price
101	1001	1.50
101	1001	1.50
101	1001	1.80
102	1001	2.10
102	1001	2.10
101	1002	10.10
101	1002	10.10
101	1002	10.10
103	1002	10.10
104	1002	20.10
104	1002	20.10
104	1002	10.10

i need to count how many times each price shows up for each product by each vendor and create a new dataframe df2 like the following:

Product	Vendor	Price	count of Price
1001	101	1.5	2
1001	101	1.8	1
1001	102	2.1	2
1002	101	10.10	3
1002	103	10.10	1
1002	104	10.10	1
1002	104	20.10	2

i am new in R programming and everything i tried so far is not working. Any help would be greatly appreciated

Answer 1

Generating fake data:

vendor <- sample(x = 1:5,size = 100,replace = TRUE)+100  
product <- sample(x = 1:8,size = 100,replace = TRUE)+1000  
price <- (product-1000) + sample(x = -8:8,size = 100,replace = TRUE)/10  
df <- data.frame(vendor,product,price) 

Solution with dplyr :

library(dplyr)  
df %>% group_by(vendor,product,price) %>% count %>% ungroup

Result :

# A tibble: 88 x 4
   vendor product price     n
    <dbl>   <dbl> <dbl> <int>
 1    101    1001   0.4     1
 2    101    1001   0.8     1
 3    101    1001   1       1
 4    101    1001   1.5     1
 5    101    1001   1.7     2
 6    101    1002   1.2     1
 7    101    1002   1.4     2
 8    101    1004   3.5     1
 9    101    1004   3.8     1
10    101    1004   3.9     2

Answer 2

Probably a duplicated question

library(dplyr)

df %>%  
  count(Product, Vendor, Price, name = "Count")

# A tibble: 7 × 4
  Product Vendor Price Count
    <dbl>  <dbl> <dbl> <int>
1    1001    101   1.5     2
2    1001    101   1.8     1
3    1001    102   2.1     2
4    1002    101  10.1     3
5    1002    103  10.1     1
6    1002    104  10.1     1
7    1002    104  20.1     2

Answer 3

This is again a duplicated question so the answer is as well!
I think n() the current group size is something that you are looking for, i.e.,

df <- read.csv(file='sof.csv') # df, your data
library(dplyr)
df %>% # df, your data
group_by(Product, Vendor, Price) %>%
summarise(`count of Price` = n())
?n() # n() gives the current group size

Answer 4

You can try aggregate like below

> aggregate(cnt ~ ., cbind(df, cnt = 1), sum)
  Vendor Product Price cnt
1    101    1001   1.5   2
2    101    1001   1.8   1
3    102    1001   2.1   2
4    101    1002  10.1   3
5    103    1002  10.1   1
6    104    1002  10.1   1
7    104    1002  20.1   2