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Lab Practice: List

Below are answers for the Lab Practice

  • Question 1: 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: Assign NULL to 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[c(2:3)] <- NULL
print(l)
## [[1]]
## [1] 1
## 
## [[2]]
## [1] 4
## 
## [[3]]
## [1] 5
  • Question 3: Add 10 to eacj element of the first vector in a given list
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
## 
## $g2
## [1] "R Programming"
## 
## $g3
## [1] "HTML"
  • Question 4: Extract all elements of a first vector except the third element of it from a given list
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: "
list1[[1]]
##  [1]  1  2  3  4  5  6  7  8  9 10
  • Question 5: Add a new item g4 = “Python” to a given list
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"
## 
## $g4
## [1] "Python"
  • Question 6: Get the length of the firs two vectors of a given list
print("Length of the vector g1 and g2 of the said list: ")
## [1] "Length of the vector g1 and g2 of the said list: "
print(length(list1$g1))
## [1] 10
print(length(list1$g2))
## [1] 1
  • Question 7: Find all elements of a given list that are not in another given list
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 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"

The end of questions