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Boston Python Workshop 3/Data types: Difference between revisions
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else:
print "Too extreme for me."
</pre>
==Lists==
* Use lists to store data where order matters.
* Lists are indexed starting with 0
====List initialization====
>>> my_list = []
>>> my_list
[]
>>> your_list = ["a", "b", "c", 1, 2, 3]
>>> your_list
['a', 'b', 'c', 1, 2, 3]
====Access and adding elements to a list====
<pre>
>>> len(my_list)
0
>>> my_list[0]
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
IndexError: list index out of range
>>> my_list.append("Alice")
>>> my_list
['Alice']
>>> len(my_list)
1
>>> my_list[0]
'Alice'
>>> my_list.insert(0, "Amy")
>>> my_list
['Amy', 'Alice']
</pre>
<pre>
>>> my_list = ['Amy', 'Alice']
>>> 'Amy' in my_list
True
>>> 'Bob' in my_list
False
</pre>
====Changing elements in a list====
<pre>
>>> your_list = []
>>> your_list.append("apples")
>>> your_list[0]
'apples'
>>> your_list[0] = "bananas"
>>> your_list
['bananas']
</pre>
====Slicing lists====
<pre>
>>> her_list = ['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h']
>>> her_list[0]
'a'
>>> her_list[0:3]
['a', 'b', 'c']
>>> her_list[:3]
['a', 'b', 'c']
>>> her_list[-1]
'h'
>>> her_list[5:]
['f', 'g', 'h']
>>> her_list[:]
['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h']
</pre>
====Sharing versus copying====
<b>Sharing</b><br />
<pre>
>>> my_list
['Alice']
>>> your_list = my_list
>>> your_list
['Alice']
>>> my_list[0] = "Bob"
>>> my_list
['Bob']
>>> your_list
['Bob']
</pre>
<b>Copying</b><br />
<pre>
>>> my_list
['Alice']
>>> your_list = my_list[:]
>>> my_list[0] = "Bob"
>>> my_list
['Bob']
>>> your_list
['Alice']
</pre>
====Strings are a lot like lists====
<pre>
>>> my_string = "Hello World"
>>> my_string[0]
'H'
>>> my_string[:5]
'Hello'
>>> my_string[6:]
'World'
>>> my_string = my_string[:6] + "Jessica"
>>> my_string
'Hello Jessica'
</pre>
====Types====
<pre>
>>> type(my_list)
<type 'list'>
</pre>
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