List methods (functions)

5.2. List methods (functions)#

Lists supports the following methods:

append(value) - add an element to the end of a list
insert(index, value) - insert an element to the list at the specified location
remove(value) - remove the first matching value from a list
pop() - remove the last element in the list; also returns the value; you can save this to another variable
pop(index) - remove the element at specified index in the list; also returns the value; you can save this to another variable
clear() - empty the list
index(element) - return position of first matching element
count(element) - return the number of elements in the list that match element;
sort() - sort the list in place
reverse() - reverse the list in place

grades = ['A', 'B', 'C']
grades.append('D')
print(grades)

['A', 'B', 'C', 'D']

grades = ['A', 'B', 'C']
grades.insert(3, 'F')
print(grades)

['A', 'B', 'C', 'F']

if the insert index is greater than the length of the list, the value will be added to the end of the list.

grades = ['A', 'B', 'C']
grades.insert(10, 'F')
print(grades)

['A', 'B', 'C', 'F']

grades = ['A', 'B', 'C']
grades.insert(0, 'F') # insert at beginning
print(grades)

['F', 'A', 'B', 'C']

grades = ['A', 'B', 'A', 'C']
grades.remove('A')
print(grades)

['B', 'A', 'C']

grades = ['A', 'B', 'C', 'D', 'F']
grades.pop() # deletes the last element in list and returns it 
print(grades)
grades.pop(0) # deletes the first element in list and returns it
print(grades)
grades.pop(2) # deletes the third element in list and returns it
print(grades)

['A', 'B', 'C', 'D']
['B', 'C', 'D']
['B', 'C']

grades = ['A', 'B', 'C']
grades.clear()
print(grades)

[]

grades = ['A', 'C', 'B', 'C']
print(grades.index('C'))

grades = ['A', 'C', 'B', 'C']
print(grades.count('C'))

grades = ['A', 'C', 'B', 'C']
grades.sort()
print(grades)

['A', 'B', 'C', 'C']

grades = ['A', 'B', 'C']
grades.reverse()
print(grades)

['C', 'B', 'A']