Adding Elements To a List

The append and insert list methods mutate (change) the original list.

append Examples

The general syntax for this method is:

list_name.append(new_value)

append adds one new item to the END of a list. The new item may be of any data type, including another list.

Example
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letters = ['a', 'b', 'c']

letters.append('a')
print(letters)

letters.append(['l', 'm', 'n', 'o', 'p'])
print(letters)

Console Output

['a', 'b', 'c', 'a']
['a', 'b', 'c', 'a', ['l', 'm', 'n', 'o', 'p']]
Note

To add multiple, separate items to the end of a list:

  1. Use multiple append statements (possibly in a loop), OR
  2. Use concatenation to add two lists together.
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letters = ['a', 'b', 'c']
digits = [0, 1, 2, 3]

for digit in digits:
letters.append(digit)   # Each iteration, add a digit to the end of the list.

print(letters)

letters = letters + ['l', 'm', 'n', 'o', 'p']
print(letters)

Console Output

['a', 'b', 'c', 0, 1, 2, 3]
['a', 'b', 'c', 0, 1, 2, 3, 'l', 'm', 'n', 'o', 'p']

insert Examples

The general syntax for this method is:

list_name.insert(index, new_value)

insert adds new_value at the specified index in the list. The new element may be of any data type, including another list.

Existing data values that come before index remain unchanged. Data values at or after index all get shifted further down the list.

Example
languages = ['Python', 'JavaScript', 'Java', 'C#']

languages.insert(2, 'Swift')
print(languages)

Output

['Python', 'JavaScript', 'Swift', 'Java', 'C#']