Practice Q1. Write an 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:"
lengths(list_data)[1] + lengths(list_data)[2]
## [1] 6
### Additional information can be extracted as bellow,
str(list_data) #Metadata about the list (General information)
## List of 2
## $ : chr [1:3] " Red " " Green " " Black "
## $ :List of 3
## ..$ : chr " Python "
## ..$ : chr " PHP "
## ..$ : chr " Java "
length(list_data) # Count the number of elements in the list
## [1] 2
lengths(list_data) #Count the number of objects within the list elements
## [1] 3 3
Practice Q2. Write an 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 2 nd and 3 rd elements to NULL ")
## [1] " Set 2 nd and 3 rd elements to NULL "
l[c(2,3)] = list(NULL)
print(l)
## [[1]]
## [1] 1
##
## [[2]]
## NULL
##
## [[3]]
## NULL
##
## [[4]]
## [1] 4
##
## [[5]]
## [1] 5
Practice Q3. Write an 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:"
s = rep(10,times =10)
list1[[1]] <- list1[[1]]+s
print(list1)
## $g1
## [1] 11 12 13 14 15 16 17 18 19 20
##
## $g2
## [1] " R Programming "
##
## $g3
## [1] " HTML "
Practice Q5. Write an 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"
Practice Q6. Write an 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"
cat("Length of g1 is" , lengths(list1)[1] , "and length of g2 is" , lengths(list1)[2]) #Count the number of objects within the list elements
## Length of g1 is 10 and length of g2 is 1
Practice Q7. Write an 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("Original lists:")
## [1] "Original 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 arenot in l1 :")
## [1] "All elements of l2 that arenot in l1 :"
setdiff(l2,l1)
## [[1]]
## [1] "X"
##
## [[2]]
## [1] "Y"
##
## [[3]]
## [1] "Z"