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cs_lang:python:things-to-know:native-datatypes

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  • Booleans
  • Numbers
  • Strings
  • Bytes
  • Lists
  • Tuples
  • Sets
  • Dictionaries

Booleans

>>> 0 == False
True
>>> a = 1
>>> a < 0
False
>>> a > 0
True
>>> 
>>> True + True
2
>>> True + False
1
>>> True * True
1
>>> True / False
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ZeroDivisionError: int division or modulo by zero

Numbers

>>> type(42)
<class 'int'>
>>> isinstance(42, int)
True
>>> 
>>> type(1 + 1.0)
<class 'float'>
>>> 
>>> float(2)
2.0
>>> int(2.5) 
2
>>> int(-2.5)
-2
>>> 
>>> 1.12345678901234567890
1.1234567890123457
>>> type(1000000000000000000000)
<class 'int'>
>>> 11 /2
5.5
>>> 1 // 2   
0
>>> -11 // 2
-6
>>> 11.0 // 2
5.0
>>> 
>>> 11 ** 2
121
>>> 11 % 2
1

Lists

>>> a_list = ["a", 1, True, "Python", 3.6465]
>>> a_list[0]
'a'
>>> a_list[-1]
3.6465
>>> 
>>> a_list[:2]
['a', 1]
>>> a_list[2:]
[True, 'Python', 3.6465]
>>> a_list[1:4]
[1, True, 'Python']
>>> 
>>> 
>>> c = a_list[:2] + a_list[2:]
>>> c
['a', 1, True, 'Python', 3.6465]
>>> 
>>> d = a_list[:]
>>> d
['a', 1, True, 'Python', 3.6465]
>>> a_list = ["a", 1, True, "Python", 3.6465]
>>> a_list.append("Toto")
>>> a_list
['a', 1, True, 'Python', 3.6465, 'Toto']
>>> 
>>> a_list.extend([42, False])
>>> a_list
['a', 1, True, 'Python', 3.6465, 'Toto', 42, False]
>>> 
>>> a_list.insert(0, 'Ω')      
>>> a_list
['Ω', 'a', 1, True, 'Python', 3.6465, 'Toto', 42, False]

List comprehension

>>> [a for a in range(0,99) if a % 2 == 0]
[0, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, 36, 38, 40, 42, 44, 46, 48, 50, 52, 54, 56, 58, 60, 62, 64, 66, 68, 70, 72, 74, 76, 78, 80, 82, 84, 86, 88, 90, 92, 94, 96, 98]
>>>
>>> [a % 2 == 0 for a in range(0,99)]
[True, False, True, False, True, False, True, False, True, False, True, False, True, False, True, False, True, False, True, False, True, False, True, False, True, False, True, False, True, False, True, False, True, False, True, False, True, False, True, False, True, False, True, False, True, False, True, False, True, False, True, False, True, False, True, False, True, False, True, False, True, False, True, False, True, False, True, False, True, False, True, False, True, False, True, False, True, False, True, False, True, False, True, False, True, False, True, False, True, False, True, False, True, False, True, False, True, False, True]
cs_lang/python/things-to-know/native-datatypes.1292173066.txt.gz · Last modified: 2010/12/12 18:05 (external edit)