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 extract initial, last, or middle characters from a string in R?
In Text analysis, we might want to extract characters from a single string or from a vector of strings. This extraction might be required to create a new string with some specific words required for further analysis. We can do this with the help of str_sub function of stringr package.
Example
Consider the below string −
> x1<-"Removing harmful things from the road is an act of charity"
Loading the stringr package −
> library(stringr) > str_sub(x1,1,8) [1] "Removing" > str_sub(x1,1,23) [1] "Removing harmful things" > str_sub(x1,29,37) [1] " the road" > str_sub(x1,30,37) [1] "the road" > str_sub(x1,-58,-51) [1] "Removing" > str_sub(x1,-58,-1) [1] "Removing harmful things from the road is an act of charity" > str_sub(x1,-7,-1) [1] "charity" > str_sub(x1,-14,-1) [1] "act of charity" > str_sub(x1,-17,-1) [1] "an act of charity"
Let’s have a look at extraction of number of characters for a vector of strings −
> x1<-c("Removing", "harmful", "things", "from", "the", "road", "is", "an", "act", "of", "charity")
> str_sub(x1,1,2)
[1] "Re" "ha" "th" "fr" "th" "ro" "is" "an" "ac" "of" "ch"
> str_sub(x1,1,3)
[1] "Rem" "har" "thi" "fro" "the" "roa" "is" "an" "act" "of" "cha"
> str_sub(x1,1,10)
[1] "Removing" "harmful" "things" "from" "the" "road"
[7] "is" "an" "act" "of" "charity"
> str_sub(x1,-7,-2)
[1] "emovin" "harmfu" "thing" "fro" "th" "roa" "i" "a"
[9] "ac" "o" "charit"
> str_sub(x1,-7,-1)
[1] "emoving" "harmful" "things" "from" "the" "road" "is"
[8] "an" "act" "of" "charity"
> str_sub(x1,-10,-1)
[1] "Removing" "harmful" "things" "from" "the" "road"
[7] "is" "an" "act" "of" "charity"
Updated on: 11-Aug-2020
984 Views
Advertisements