103 lines
1.5 KiB
Markdown
103 lines
1.5 KiB
Markdown
---
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tags: [python, data-structures]
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---
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# Tuples in Python
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TODO: Exapand tuple notes - give more use cases
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Tuples are one of the main data-structures or containers in Python. Tuples are
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useful in cases where you want to group related data and ensure that it will not
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change.
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Tuples have the following properties:
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- They are **ordered**
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- They have a **fixed size**
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- They are **immutable** and cannot be modified
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- **Allow duplicate** members
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- They are **indexed**
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> In essence a tuple is a list that is immutable.
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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[2])
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# 5
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"""
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```
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## Slicing
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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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(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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```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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"""
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apple
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pear
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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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# 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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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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# (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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