cs_lang:python:things-to-know:native-datatypes
Table of Contents
- Booleans
- Numbers
- Strings
- Bytes
- Lists
- Tuples
- Sets
- Dictionaries
Booleans
>>> x = 42 >>> 19 <= x <= 51 True >>> 19 <= x <= 41 False >>> >>> 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
>>> import this >>> love = this >>> this is love True >>> love is True False >>> love is False False >>> love is not True or False True >>> love is not True or False; love is love True True
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] >>> >>> a_list.append((42, False)) >>> a_list ['Ω', 'a', 1, True, 'Python', 3.6465, 'Toto', 42, False, (42, False)] >>> >>> len(a_list) 10 >>> a_list[-1] (42, False)
Dictionaries
>>> a_dict = {'server': 'cedricbonhomme.org', 'database':'mysql'} >>> >>> a_dict['blog'] Traceback (most recent call last): File "<stdin>", line 1, in <module> KeyError: 'blog' >>> 'blog' in a_dict False >>> a_dict['blog'] = 'wordpress' >>> a_dict {'blog': 'dotclear', 'database': 'mysql', 'server': 'cedricbonhomme.org'} >>> >>> >>> a_dict.keys() dict_keys(['blog', 'database', 'server']) >>> a_dict.values() dict_values(['dotclear', 'mysql', 'cedricbonhomme.org'])
cs_lang/python/things-to-know/native-datatypes.txt · Last modified: 2011/01/11 14:26 by cedric