Autosave: 2023-02-15 07:36:48
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thomasabishop
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5 changed files with 241 additions and 29 deletions
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@ -15,3 +15,145 @@ Lists have the following properties:
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- They **allow duplicate** members
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- They are **indexed**
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- You can increase/decrease their length by adding/removing new members
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> Lists are denoted with `[...]`
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## Basic usage
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```python
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# Defining a list
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list1 = ['John', 'Paul', 'George', 'Ringo']
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list2 = [4]
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# Empty list
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list3 = [] # empty list
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list3 = list() # Also empty list
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# Nested list
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list5 = [[2, 3], [6, 8]]
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```
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## Slicing
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```python
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list1 = ['John', 'Paul', 'George', 'Ringo']
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print(list1[1])
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print(list1[-1])
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print(list1[1:3])
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print(list1[:3])
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print(list1[1:])
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"""
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Ringo
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['Paul', 'George']
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['John', 'Paul', 'George']
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['Paul', 'George', 'Ringo']
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"""
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```
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## Adding additional values to existing list
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```python
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list1 = ['John', 'Paul', 'George', 'Ringo']
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# Add single element to the end of a list
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list1.append('Pete')
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# ['John', 'Paul', 'George', 'Ringo', 'Pete']
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# Add multiple elements to end of a list
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list1.extend(['Albert', 'Bob'])
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list1 += ['Ginger', 'Sporty']
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# ['John', 'Paul', 'George', 'Ringo', 'Pete', 'Albert', 'Bob', 'Ginger', 'Sporty']
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## Insert at specific index
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list1.insert(2, 7)
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['John', 'Paul', 7, 'George', 'Ringo', 'Pete', 'Albert', 'Bob', 'Ginger', 'Sporty']
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a_list = ['Adele', 'Madonna', 'Cher']
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print(a_list)
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a_list.insert(1, 'Paloma')
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print(a_list)
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# ['Adele', 'Paloma', 'Madonna', 'Cher']
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```
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## Removing elements
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We distinguish `del` from `remove` when removing elements from lists:
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- `del` requires an index value
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- `remove` requires a value reference (i.e. the mame of the element rather than its index)
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`del` is simple deletion whereas `remove` searches the list. Therefore `del` is more efficient.
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```python
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# Remove and return element removed
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list6 = ['Once', 'Upon', 'a', 'Time']
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print(list6.pop(2))
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# a
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# Remove and return last element
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list6 = ['Once', 'Upon', 'a', 'Time']
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print(list6.pop())
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list6.pop()
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print(list6)
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# Time
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list6.remove('Upon')
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print(list6)
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# ['Once', 'a']
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my_list = ['A', 'B', 'C', 'D', 'E']
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print(my_list)
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# ['A', 'B', 'C', 'D', 'E']
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del my_list[2]
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print(my_list)
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# ['A', 'B', 'D', 'E']
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print(my_list)
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# ['A', 'B', 'C', 'D', 'E']
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del my_list[1:3]
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print(my_list)
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# ['A', 'D', 'E']
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```
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## Retrieve elements by index
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```python
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list7 = [2, 3, 6, 8]
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print(list7.index(8))
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# 3
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list6 = ['Once', 'Upon', 'a', 'Time']
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print(list6.index('a'))
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# 2
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```
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## Nesting lists
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```python
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l1 = [1, 43.5, 'Phoebe', True]
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l2 = ['apple', 'orange', 31]
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root_list = ['John', l1, l2, 'Denise']
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print(root_list)
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# ['John', [1, 43.5, 'Phoebe', True], ['apple', 'orange', 31], 'Denise']
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```
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## List comprehension
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> List comprehension is an older feature of Python. Now the same functionality can be achieved with greater concision using functional methods like `map` and `filter`. But you may see it used in older code.
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```python
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values = [1, 2, 4, 6, 8, 9]
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new_values = [i + 1 for i in values]
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print('new_values', new_values)
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# new_values [2, 3, 5, 7, 9, 10]
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new_list = [item + 1 for item in values if item % 2 == 0]
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print('new_list:', new_list)
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# new_list: [3, 5, 7, 9]
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```
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@ -10,3 +10,50 @@ tags: [python, data-structures]
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- You can increase/decrease their length by adding/removing new members
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- They **do not allow duplicate members**
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- **Can only hold immutable objects**
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> Sets are denoted with `{...}`
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## Basic usage
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```python
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basket = {'apple', 'orange', 'apple', 'pear', 'orange', 'banana'}
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print(basket) # show that duplicates have been removed
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print(len(basket))
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# {'apple', 'pear', 'banana', 'orange'}
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# 4
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```
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## Looping through sets
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```python
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for item in basket:
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print(item)
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"""
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apple
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pear
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banana
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orange
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"""
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```
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## Check for membership
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```python
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basket = {'apple', 'orange', 'apple', 'pear', 'orange', 'banana'}
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print('apple' in basket)
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# True
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```
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## Remove items from set
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> `remove` will raise an error if the specified item does not exist, `discard` will not
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```python
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basket.remove('apple')
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basket.discard('apricot')
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print(basket)
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# {'pear', 'banana', 'orange'}
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```
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## Add items to a set
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@ -16,43 +16,48 @@ Tuples have the following properties:
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- **Allow duplicate** members
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- They are **indexed**
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As with all containers in Python they permit any data type.
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> Tuples are denoted with `(...)`
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## Basic usage
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```python
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tup1 = (1, 3, 5, 7)
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print('tup1[0]:\t', tup1[0])
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print('tup1[1]:\t', tup1[1])
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print('tup1[2]:\t', tup1[2])
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print('tup1[3]:\t', tup1[3])
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print(tup1[0])
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print(tup1[1])
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print(tup1[2])
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print(tup1[3])
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"""
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tup1[0]: 1
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tup1[1]: 3
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tup1[2]: 5
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tup1[3]: 7
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1
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3
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5
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7
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"""
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```
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# Slicing
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## Slicing
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print('tup1[1:3]:\t', tup1[1:3])
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print('tup1[:3]:\t', tup1[:3])
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print('tup1[1:]:\t', tup1[1:])
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print('tup1[::-1]:\t', tup1[::-1])
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```python
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tup1 = (1, 3, 5, 7)
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print(tup1[1:3])
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print(tup1[:3])
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print(tup1[1:])
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print(tup1[::-1])
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"""
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tup1[1:3]: (3, 5)
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tup1[:3]: (1, 3, 5)
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tup1[1:]: (3, 5, 7)
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tup1[::-1]: (7, 5, 3, 1)
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(3, 5)
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(1, 3, 5)
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(3, 5, 7)
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(7, 5, 3, 1)
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"""
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```
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## Looping
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print('len(tup1):\t', len(tup1))
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# len(tup1): 4
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tup2 = (1, 'John', True, -23.45)
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print(tup2)
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# (1, 'John', True, -23.45)
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```python
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tup3 = ('apple', 'pear', 'orange', 'plum', 'apple')
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for x in tup3:
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print(x)
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@ -64,20 +69,32 @@ orange
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plum
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apple
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"""
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```
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## Useful methods and predicates
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```python
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tup3 = ('apple', 'pear', 'orange', 'plum', 'apple')
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# Count instances of a member
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print(tup3.count('apple'))
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print(tup3.index('pear'))
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# 2
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# Get index of a member
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print(tup3.index('pear'))
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# 1
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# Check for membership
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if 'orange' in tup3:
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print('orange is in the Tuple')
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# orange is in the Tuple
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```
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## Nest tuples
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```python
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tuple1 = (1, 3, 5, 7)
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tuple2 = ('John', 'Denise', 'Phoebe', 'Adam')
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tuple3 = (42, tuple1, tuple2, 5.5)
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print(tuple3)
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@ -85,3 +102,5 @@ print(tuple3)
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# (42, (1, 3, 5, 7), ('John', 'Denise', 'Phoebe', 'Adam'), 5.5)
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```
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// TODO: How to flatten a tuple?
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@ -96,6 +96,10 @@ A. Sweighart. 2020. **Beyond the Basic Stuff with Python**
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A. Sweighart. 2015. **Automate the Boring Stuff with Python**
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J. Hunt. 2019. **A Beginner's Guide to Python Programming**
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J. Hunt. 2019. **An Advanced Guide to Python Programming**
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[Tiny Python Projects (O'Reilly)](https://learning.oreilly.com/library/view/tiny-python-projects/9781617297519/)
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[Learning Arduino with Python](https://realpython.com/arduino-python/)
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