Lists Methods

Append

  1. # add to end
  2. fruits = ["apple", "banana"]
  3. fruits.append("cherry")
  4. #ans: ["apple", "banana", "cherry"]

Insert

  1. # insert at index
  2. fruits = ["apple", "cherry"]
  3. fruits.insert(1, "banana")
  4. #ans: ["apple", "banana", "cherry"]

Extend

  1. # add multiple items
  2. fruits = ["apple"]
  3. fruits.extend(["banana", "cherry"])
  4. #ans: ["apple", "banana", "cherry"]

Remove

  1. # remove by value
  2. fruits = ["apple", "banana", "cherry"]
  3. fruits.remove("banana")
  4. #ans: ["apple", "cherry"]

Pop

  1. # remove and return
  2. fruits = ["apple", "banana", "cherry"]
  3. last = fruits.pop()
  4. #ans: last is "cherry"
  5. #ans: fruits is ["apple", "banana"]
  6. first = fruits.pop(0)
  7. #ans: first is "apple"

Sort

  1. # sort in place
  2. numbers = [3, 1, 4, 1, 5]
  3. numbers.sort()
  4. #ans: [1, 1, 3, 4, 5]
  5. numbers.sort(reverse=True)
  6. #ans: [5, 4, 3, 1, 1]

Reverse

  1. # reverse in place
  2. lst = [1, 2, 3]
  3. lst.reverse()
  4. #ans: [3, 2, 1]

Count

  1. # count occurrences
  2. numbers = [1, 2, 3, 2, 4, 2]
  3. numbers.count(2)
  4. #ans: 3

Index

  1. # find index
  2. fruits = ["apple", "banana", "cherry"]
  3. fruits.index("banana")
  4. #ans: 1

Clear

  1. # remove all
  2. fruits = ["apple", "banana"]
  3. fruits.clear()
  4. #ans: []

Exercises - Part 1

  1. # what is lst after append?
  2. lst = [1, 2]
  3. lst.append(3)
  4. #ans: [1, 2, 3]

Exercises - Part 2

  1. # insert at position?
  2. lst = [1, 3, 4]
  3. lst.insert(1, 2)
  4. #ans: [1, 2, 3, 4]

Exercises - Part 3

  1. # extend vs append?
  2. lst = [1, 2]
  3. lst.extend([3, 4])
  4. #ans: [1, 2, 3, 4]
  5. lst = [1, 2]
  6. lst.append([3, 4])
  7. #ans: [1, 2, [3, 4]]

Exercises - Part 4

  1. # pop without argument?
  2. lst = [1, 2, 3]
  3. lst.pop()
  4. #ans: 3
  5. #ans: lst is [1, 2]

Exercises - Part 5

  1. # remove first occurrence?
  2. lst = [1, 2, 2, 3]
  3. lst.remove(2)
  4. #ans: [1, 2, 3]

Exercises - Part 6

  1. # sort return value?
  2. lst = [3, 1, 2]
  3. result = lst.sort()
  4. #ans: result is None (sorts in place)

Exercises - Part 7

  1. # index not found?
  2. lst = [1, 2, 3]
  3. lst.index(5)
  4. #ans: ValueError

Exercises - Part 8

  1. # count non-existent?
  2. lst = [1, 2, 3]
  3. lst.count(5)
  4. #ans: 0

Exercises - Part 9

  1. # reverse return?
  2. lst = [1, 2, 3]
  3. result = lst.reverse()
  4. #ans: result is None (reverses in place)

Exercises - Part 10

  1. # clear return?
  2. lst = [1, 2, 3]
  3. result = lst.clear()
  4. #ans: result is None
  5. #ans: lst is []

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