Source Code for Module basics.lists

 1  """ 
 2  Python uses square brackets to enclose B{lists}. 
 3   
 4     >>> X = [24, 3.14, 'w', 7] #  List with 4 items 
 5     >>> Y = [100]    # list with one item 
 6     >>> Z = [] #empty list 
 7   
 8  Lists are sequences of items which may be of different data types. 
 9   
10     >>> L = list('hi!')  # make a string a list 
11     >>> L 
12     ['h', 'i', '!'] 
13     >>> M = list() 
14     >>> M 
15     [] 
16   
17  The following examples illustrate references to list elements 
18  or list subsequences: 
19   
20     >>> X[0]   # 1st element 
21     24 
22     >>> X[1]   # 2nd element 
23     3.1400000000000001 
24     >>> X[-1]   # last element 
25     7 
26     >>> X[0:2] # list of 1st and 2nd elements 
27     [24, 3.1400000000000001] 
28     >>> X[:-1] # list excluding last element 
29   
30  References to subsequences of a list are called 
31  X{slices}.  The following raises an IndexError 
32   
33     >>> X[4]   # Raises exception! 
34     ... 
35     IndexError: list index out of range 
36     >>> X + Y # Concatenation! 
37     [24, 3.1400000000000001, 'w', 7, 100] 
38   
39  Lists allow X{value assignments}, which change the value of a reference 
40  in place (X{in place assignment}). 
41   
42     >>> X[2] = 5 
43     >>> X 
44     [24, 3.1400000000000001, 5, 7] 
45     >>> X[0:2] = [1,3] 
46     >>> X 
47     [1, 3, 5, 7] 
48   
49  Only list-values can be assigned to slices. 
50  """ 
51   
52   
53 -def demo_lists(): 
54      global X, Y, Z, L, M 
55       
56      X = [24, 3.14, 'w', 7] #  List with 4 items 
57      print X 
58      Y = [100]    # list with one item 
59      Z = [] #empty list 
60   
61      L = list('hi!')  # make a string a list 
62      M = list() 
63   
64      X[0]   # 1st element 
65      X[1]   # 2nd element 
66      X[-1]   # last element 
67      X[0:2] # list of 1st and 2nd elements 
68      X[:-1] # list excluding last element 
69   
70       
71      X + Y # Concatenation! 
72      X[2] = 5 
73      print X 
74   
75  if __name__ == '__main__': 
76      demo_lists() 
77