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"
print(length(list_data))
## [1] 2

Question 2

Write a R program to assign NULL to a given list element?

l=list(1,2,3,4,5)
print("Original list:")
## [1] "Original list:"
print(l)
## [[1]]
## [1] 1
## 
## [[2]]
## [1] 2
## 
## [[3]]
## [1] 3
## 
## [[4]]
## [1] 4
## 
## [[5]]
## [1] 5
print("Set 2nd and 3rd elements to NULL")
## [1] "Set 2nd and 3rd elements to NULL"
l[2] <- list(NULL)
l[3] <- list(NULL)
print(l)
## [[1]]
## [1] 1
## 
## [[2]]
## NULL
## 
## [[3]]
## NULL
## 
## [[4]]
## [1] 4
## 
## [[5]]
## [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"
## 
## $g3
## [1] "HTML"
print("New list:")
## [1] "New list:"
list1$g1 <- list1$g1 + 10
print(list1$g1)
##  [1] 11 12 13 14 15 16 17 18 19 20

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" )
print("Original list:")
## [1] "Original list:"
print(list1)
## $g1
##  [1]  1  2  3  4  5  6  7  8  9 10
## 
## $g2
## [1] "R Programming"
## 
## $g3
## [1] "HTML"
print("First vector")
## [1] "First vector"
print("First vector except thied element")
## [1] "First vector except thied element"
list1$g1 <- list1$g1[-3]
print(list1$g1)
## [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")
print("Original list:")
## [1] "Original list:"
print(list1)
## $g1
##  [1]  1  2  3  4  5  6  7  8  9 10
## 
## $g2
## [1] "R Programming"
## 
## $g3
## [1] "HTML"
print("Add a new vector to the said list")
## [1] "Add a new vector to the said list"
list1$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"
## 
## $g3
## [1] "HTML"
print(" Length of the vector g1 and g2 of the said list")
## [1] " Length of the vector g1 and g2 of the said list"
print(length(list1$g1))
## [1] 10
print(length(list1$g2))
## [1] 1

Question 7

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

l1 <- list("x","y","z")
l2 <- list("X","Y","Z","x","y","z")
print("Priginanl lists:")
## [1] "Priginanl lists:"
print(l1)
## [[1]]
## [1] "x"
## 
## [[2]]
## [1] "y"
## 
## [[3]]
## [1] "z"
print(l2)
## [[1]]
## [1] "X"
## 
## [[2]]
## [1] "Y"
## 
## [[3]]
## [1] "Z"
## 
## [[4]]
## [1] "x"
## 
## [[5]]
## [1] "y"
## 
## [[6]]
## [1] "z"
print("All elements of l2 that are not in l1:")
## [1] "All elements of l2 that are not in l1:"
setdiff(l2,l1)
## [[1]]
## [1] "X"
## 
## [[2]]
## [1] "Y"
## 
## [[3]]
## [1] "Z"

All lab 3 practice ,thank you so much Dr.