**R-exercises**, and kindly contributed to R-bloggers)

For a begineer in R or any language,regular expression might seem like a daunting task . Rebus package in R gives a lowers the barrier for common regular expression tasks and is useful for a begineer or even for advanced users for most of the common regex skills in a more intuitive yet verbose way .Check out the package and try this exercises to test your knowledge .

Load stringr/stringi as well for this set of exercise . I encourage you to do this and

this before working on this set .

Answers are available here.

If you obtained a different (correct) answer than those listed on the solutions page, please feel free to post your answer as a comment on that page.

**Exercise 1**

create two strings

Suppose you have a vectore

` x <- c("stringer","stringi","rebus","redbus") `

use rebus and find the strings starting with st .Hint use START from rebus

**Exercise 2**

Use the same string vectore and find the strings which ends with bus.

**Exercise 3**

you have a vector like

` m <- c("aba","aca","abba","accdda")`

find the strings which starts and ends with a and have a single character in between

Hint – use ANY_CHAR

**Exercise 4**

` y <- c("brain","brawn","rain","train") `

find all the strings that starts with br and ends with n .

Hint – use any_char with hi=Inf to build the regex

**Exercise 5**

Use the same vector as previous exercise and find strings starting with br or tr .

Hint – or

**Exercise 6**

Now we turn our attention to character class,if you are familiar with character classes in regex , you will find it pretty easy with rebus and if you are starting with regex .you might find it easy to remember with rebus

Suppose you have a vector

` l <- c("Canada","america","france") `

Find string with C or m in it .so your answer should be Canada and America

**Exercise 7**

From the string 123abc ,find the digits ,using rebus .

**Exercise 8**

Create a character class for vowels and find all the Vowels in the vector

` vow <- c("blue","sue","CLUE","TRUE") `

**Exercise 9**

Find the characters other than vowels from above vector .

**Exercise 10**

Now create a new vector

` vow1 <- c("blue","sue","CLUE","TRUE","aue")`

find the string which is made of only vowels

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