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
Apply a mathematical operation on rows of an R data frame stored in a list.
To apply a mathematical operation such as multiplication, division, subtraction and addition on rows of an R data frame stored in a list, we can use apply function.
For Example, if we have a list called LIST that contains a data frame df with two columns say X and Y and we want to add rows of df then we can use the command mentioned below −
apply(df,1,function(x) x["X"]+x["Y"])
Check out the Example given below to understand how it can be done.
Example
Following snippet creates a sample data frames: −
x1<-rnorm(20) y1<-rnorm(20) df1<-data.frame(x1,y1) x2<-rpois(20,5) y2<-rpois(20,5) df2<-data.frame(x2,y2) List<-list(df1,df2) List
The list of these data frames is as follows −
[[1]]
x1 y1
1 -1.5731993 0.11244718
2 -1.9456438 0.20793065
3 0.6984799 1.21806315
4 -0.9044348 1.15796145
5 -1.3220205 1.51746076
6 -2.4595593 1.19932839
7 0.7052369 0.46857422
8 0.2257025 1.19549664
9 1.7703144 -0.90544795
10 -1.1280562 1.19661179
11 1.3450602 1.08065271
12 -0.4960736 0.82348313
13 0.2703035 -0.89962056
14 1.6588146 0.01264785
15 0.9652318 0.70363607
16 -1.6510901 1.53432591
17 -0.5948874 0.46737082
18 -0.3386917 -0.01119323
19 0.6576946 0.14457605
20 0.5898998 -1.75455914
[[2]]
x2 y2
1 9 5
2 3 4
3 10 6
4 2 2
5 7 1
6 2 6
7 3 4
8 4 5
9 6 9
10 2 6
11 6 9
12 4 5
13 2 5
14 3 4
15 6 4
16 3 12
17 8 6
18 8 3
19 4 4
20 3 4To divide row values in x1 by y1 for each row in df1 on the above created data frames, add the following code to the above snippet −
x1<-rnorm(20) y1<-rnorm(20) df1<-data.frame(x1,y1) x2<-rpois(20,5) y2<-rpois(20,5) df2<-data.frame(x2,y2) List<-list(df1,df2) apply(df1,1,function(x) x["x1"]/x["y1"])
Output
If you execute all the above given snippets as a single program, it generates the following Output −
[1] -13.9905627 -9.3571763 0.5734349 -0.7810578 -0.8712057 -2.0507805 [7] 1.5050697 0.1887939 -1.9551808 -0.9427085 1.2446739 -0.6024089 [13] -0.3004639 131.1538482 1.3717771 -1.0761013 -1.2728382 30.2586086 [19] 4.5491260 -0.3362097
To multiply row values in x2 with y2 for each row in df2 on the above created data frames, add the following code to the above snippet −
x1<-rnorm(20) y1<-rnorm(20) df1<-data.frame(x1,y1) x2<-rpois(20,5) y2<-rpois(20,5) df2<-data.frame(x2,y2) List<-list(df1,df2) apply(df2,1,function(x) x["x2"]*x["y2"])
Output
If you execute all the above given snippets as a single program, it generates the following Output −
[1] 45 12 60 4 7 12 12 20 54 12 54 20 10 12 24 36 48 24 16 12
1K+ Views
