Countif in R programming

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

Solution

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