Data Structure
Networking
RDBMS
Operating System
Java
MS Excel
iOS
HTML
CSS
Android
Python
C Programming
C++
C#
MongoDB
MySQL
Javascript
PHP
Physics
Chemistry
Biology
Mathematics
English
Economics
Psychology
Social Studies
Fashion Studies
Legal Studies
- Selected Reading
- UPSC IAS Exams Notes
- Developer's Best Practices
- Questions and Answers
- Effective Resume Writing
- HR Interview Questions
- Computer Glossary
- Who is Who
How to find the total of frequency based on the values of a factor column in R?
Often, we have duplicate values in a factor column that means a factor column has many levels and each of these levels occur many times. In this situation, if we have a frequency column then we want to find the total of that frequency based on the values of a factor column and this can be done by using aggregate function.
Example
Consider the below data frame −
> set.seed(109) > Class<-rep(sample(LETTERS[1:5],4),times=5) > Frequency<-sample(1:10,20,replace=TRUE) > df1<-data.frame(Class,Frequency) > df1
Output
Class Frequency 1 E 9 2 D 5 3 B 10 4 C 10 5 E 7 6 D 10 7 B 9 8 C 5 9 E 8 10 D 7 11 B 1 12 C 3 13 E 5 14 D 10 15 B 2 16 C 3 17 E 9 18 D 3 19 B 2 20 C 9
Finding the sum of frequency for each class −
> aggregate(df1["Frequency"],by=df1["Class"],sum)
Output
Class Frequency 1 B 24 2 C 30 3 D 35 4 E 38
Lets’ have a look at another example −
Example
> Metal<-rep(c("Iron","Nickel","Lead","Zinc","Tin","Sodium","Silver"),times=5)
> Quantity<-sample(20:50,35,replace=TRUE)
> df2<-data.frame(Metal,Quantity)
> head(df2,10)Metal Quantity 1 Iron 43 2 Nickel 33 3 Lead 25 4 Zinc 24 5 Tin 27 6 Sodium 34 7 Silver 31 8 Iron 37 9 Nickel 36 10 Lead 24 > tail(df2,10) Metal Quantity 26 Tin 49 27 Sodium 43 28 Silver 47 29 Iron 28 30 Nickel 41 31 Lead 21 32 Zinc 33 33 Tin 44 34 Sodium 34 35 Silver 33
> aggregate(df2["Quantity"],by=df2["Metal"],sum)
Output
Metal Quantity 1 Iron 157 2 Lead 148 3 Nickel 174 4 Silver 165 5 Sodium 161 6 Tin 192 7 Zinc 155
Updated on: 04-Sep-2020
327 Views
Advertisements