Dinesh V M Ramachandran

Question 1

Write a R program to count number of objects in a given list?

list_data <-  list( c(" Red "," Green "," Black "),list(" Python ", " PHP ", " Java "))
print(" List:")
## [1] " List:"
print( list_data )
## [[1]]
## [1] " Red "   " Green " " Black "
## 
## [[2]]
## [[2]][[1]]
## [1] " Python "
## 
## [[2]][[2]]
## [1] " PHP "
## 
## [[2]][[3]]
## [1] " Java "
print(" Number    of    objects    in    the    said    list:")
## [1] " Number    of    objects    in    the    said    list:"
length(list_data)
## [1] 2

Question 2

Write a R program to assign NULL to a given list element? Original List:

l   =    list(1 , 2 , 3 , 4 , 5)

Set 2nd and 3rd elements to NULL

l[c(2,3)] <- NULL
print(l)
## [[1]]
## [1] 1
## 
## [[2]]
## [1] 4
## 
## [[3]]
## [1] 5

Question 3

Write a R program to Add 10 to each element of the first vector in a given list? Sample list: (g1 = 1:10, g2 = “R Programming”, g3 = “HTML”).

list1 <- list(g1= 1:10, g2= "R Programming", g3 = "HTML")
print ("Original List")
## [1] "Original List"
print(list1)
## $g1
##  [1]  1  2  3  4  5  6  7  8  9 10
## 
## $g2
## [1] "R Programming"
## 
## $g3
## [1] "HTML"
list1$g1 = list1$g1 +10
print ("New List")
## [1] "New List"
print(list1)
## $g1
##  [1] 11 12 13 14 15 16 17 18 19 20
## 
## $g2
## [1] "R Programming"
## 
## $g3
## [1] "HTML"

Question 4

Write a R program to extract all elements of a first vector except the third element of it from a given list. Sample list: (g1 = 1:10, g2 = “R Programming”, g3 = “HTML”).

list1 = list( g1  = 1:10 , g2  = "R Programming", g3= "HTML")

Original list:

print( list1 )
## $g1
##  [1]  1  2  3  4  5  6  7  8  9 10
## 
## $g2
## [1] "R Programming"
## 
## $g3
## [1] "HTML"

First vector:

print(list1[[1]][-3])
## [1]  1  2  4  5  6  7  8  9 10

Question 5

Write a R program to add a new item g4 =“Python” to a given list. Sample list: (g1 = 1:10, g2 = “R Programming”, g3 = “HTML”).

list1 = list( g1  = 1:10 , g2  = " R Programming ", g3 = " HTML ")

Original list:

print( list1 )
## $g1
##  [1]  1  2  3  4  5  6  7  8  9 10
## 
## $g2
## [1] " R Programming "
## 
## $g3
## [1] " HTML "

Add a new vector to the said list:“)

list1['g4'] <- 'Python'
print (list1)
## $g1
##  [1]  1  2  3  4  5  6  7  8  9 10
## 
## $g2
## [1] " R Programming "
## 
## $g3
## [1] " HTML "
## 
## $g4
## [1] "Python"

Question 6

Write a R program to get the length of the first two vectors of a given list. Sample list: (g1 = 1:10, g2 = “R Programming”, g3 = “HTML”).

list1 = list( g1= 1:10 , g2  = " R  Programming ", g3 =" HTML ")
print(" Original list:")
## [1] " Original list:"
print( list1 )
## $g1
##  [1]  1  2  3  4  5  6  7  8  9 10
## 
## $g2
## [1] " R  Programming "
## 
## $g3
## [1] " HTML "

Length of the vector g1 and g2 of the said???’ list”)

print(length(list1[['g1']]))
## [1] 10
print(length(list1[['g2']]))
## [1] 1

Quesiton 7

Write a R program to find all elements of a given list that are not in another given list? Hint, see setdiff(..).

Original list:

l1 = list ("x", "y", "z")
l2 = list ("X", "Y", "Z", "x", "y", "z")

All elements that are not in l1:

print(setdiff(l2,l1))
## [[1]]
## [1] "X"
## 
## [[2]]
## [1] "Y"
## 
## [[3]]
## [1] "Z"