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 get row index based on a value of an R data frame column?
A row of an R data frame can have multiple ways in columns and these values can be numerical, logical, string etc. It is easy to find the values based on row numbers but finding the row numbers based on a value is different. If we want to find the row number for a particular value in a specific column then we can extract the whole row which seems to be a better way and it can be done by using single square brackets to take the subset of the row.
Example
Consider the below data frame −
x1<-rnorm(20,0.5) x2<-rpois(20,2) x3<-rpois(20,5) x4<-rpois(20,10) x5<-rnorm(20,2) df<-data.frame(x1,x2,x3,x4,x5) df
Output
x1 x2 x3 x4 x5 1 1.33780769 1 5 1 3.3322153 2 2.22651263 3 5 14 3.4969403 3 0.53231950 4 9 8 3.7816594 4 0.99704756 1 6 13 2.7308284 5 0.37735760 2 5 7 2.3210021 6 0.96967898 3 7 8 1.9086576 7 0.06543569 2 4 9 1.4005479 8 1.59064892 1 8 14 1.1250329 9 0.48771130 1 4 11 2.2479028 10 0.64134261 0 9 5 2.4194513 11 0.43355439 3 2 18 -0.7633724 12 1.31803573 3 4 10 2.6201427 13 0.25367683 3 6 9 1.5728880 14 1.07884550 5 4 9 0.8045540 15 0.78574641 6 6 8 1.3538888 16 -0.27873444 2 6 12 3.5431787 17 0.28112519 2 3 8 4.1865617 18 1.24416762 4 4 11 2.3626763 19 -0.04745463 2 5 13 3.4203297 20 1.33358241 1 9 14 2.8205837
Finding the rows that will also return row indexes for a value −
Example
df[df$x4==14,]
Output
x1 x2 x3 x4 x5 2 2.226513 3 5 14 3.496940 8 1.590649 1 8 14 1.125033 20 1.333582 1 9 14 2.820584
Example
df[df$x4==12,]
Output
x1 x2 x3 x4 x5 16 -0.2787344 2 6 12 3.543179
Example
df[df$x4==7,]
Output
x1 x2 x3 x4 x5 5 0.3773576 2 5 7 2.321002
Example
df[df$x4==9,]
Output
x1 x2 x3 x4 x5 7 0.06543569 2 4 9 1.400548 13 0.25367683 3 6 9 1.572888 14 1.07884550 5 4 9 0.804554
example
df[df$x2==2,]
Output
x1 x2 x3 x4 x5 5 0.37735760 2 5 7 2.321002 7 0.06543569 2 4 9 1.400548 16 -0.27873444 2 6 12 3.543179 17 0.28112519 2 3 8 4.186562 19 -0.04745463 2 5 13 3.420330
Example
df[df$x2==5,]
Output
x1 x2 x3 x4 x5 14 1.078845 5 4 9 0.804554
Example
df[df$x2==4,]
Output
x1 x2 x3 x4 x5 3 0.5323195 4 9 8 3.781659 18 1.2441676 4 4 11 2.362676
Example
df[df$x3==4,]
Output
x1 x2 x3 x4 x5 7 0.06543569 2 4 9 1.400548 9 0.48771130 1 4 11 2.247903 12 1.31803573 3 4 10 2.620143 14 1.07884550 5 4 9 0.804554 18 1.24416762 4 4 11 2.362676
Example
df[df$x3==6,]
Output
x1 x2 x3 x4 x5 4 0.9970476 1 6 13 2.730828 13 0.2536768 3 6 9 1.572888 15 0.7857464 6 6 8 1.353889 16 -0.2787344 2 6 12 3.543179
Example
df[df$x3==5,]
Output
x1 x2 x3 x4 x5 1 1.33780769 1 5 1 3.332215 2 2.22651263 3 5 14 3.496940 5 0.37735760 2 5 7 2.321002 19 -0.04745463 2 5 13 3.420330
Example
df[df$x3==8,]
Output
x1 x2 x3 x4 x5 8 1.590649 1 8 14 1.125033
Example
df[df$x2==1,]
Output
x1 x2 x3 x4 x5 1 1.3378077 1 5 1 3.332215 4 0.9970476 1 6 13 2.730828 8 1.5906489 1 8 14 1.125033 9 0.4877113 1 4 11 2.247903 20 1.3335824 1 9 14 2.820584
Updated on: 08-Sep-2020
4K+ Views
Advertisements