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6 """This provides useful general functions for working with lists (OBSOLETE).
7
8 This module and its C code equivalent are considered to be obsolete, and
9 are likely to be deprecated in a future release of Biopython, before being
10 removed. Please get in touch via the mailing list if this will affect you.
11 Many of these functions can be avoided using the python set object.
12
13 Functions:
14 asdict Make the list into a dictionary (for fast testing of membership).
15 items Get one of each item in a list.
16 count Count the number of times each item appears.
17 contents Calculate percentage each item appears in a list.
18 itemindex Make an index of the items in the list.
19 intersection Get the items in common between 2 lists.
20 difference Get the items in 1 list, but not the other.
21 indexesof Get a list of the indexes of some items in a list.
22 take Take some items from a list.
23
24 """
25
27 """asdict(l) -> dictionary
28
29 Return a dictionary where the keys are the items in the list, with
30 arbitrary values. This is useful for quick testing of membership.
31
32 """
33 return count(l)
34
36 """items(l) -> list of items
37
38 Generate a list of one of each item in l. The items are returned
39 in arbitrary order.
40
41 """
42 try:
43 return asdict(l).keys()
44 except TypeError, x:
45 if str(x).find("unhashable") == -1:
46 raise
47
48
49 l = l[:]
50 l.sort()
51 i = 0
52 while i < len(l)-1:
53 if l[i] == l[i+1]:
54 del l[i]
55 else:
56 i += 1
57 return l
58
60 """count(items) -> dict of counts of each item
61
62 Count the number of times each item appears in a list of data.
63
64 """
65 c = {}
66 for i in items:
67 c[i] = c.get(i, 0) + 1
68 return c
69
71 """contents(items) -> dict of item:percentage
72
73 Summarize the contents of the list in terms of the percentages of each
74 item. For example, if an item appears 3 times in a list with 10 items,
75 it is in 0.3 of the list.
76
77 """
78 counts = count(items)
79 l = float(len(items))
80 contents = {}
81 for i, c in counts.items():
82 contents[i] = c / l
83 return contents
84
86 """intersection(l1, l2) -> list of common items
87
88 Return a list of the items in both l1 and l2. The list is in
89 arbitrary order.
90
91 """
92 inter = []
93 words1 = count(l1)
94 for w in l2:
95 if words1.has_key(w):
96 inter.append(w)
97 del words1[w]
98 return inter
99
101 """difference(l1, l2) -> list of items in l1, but not l2
102
103 Return a list of the items in l1, but not l2. The list is in
104 arbitrary order.
105
106 """
107 diff = []
108 words2 = count(l2)
109 for w in l1:
110 if not words2.has_key(w):
111 diff.append(w)
112 words2[w] = 1
113 return diff
114
116 """itemindex(l) -> dict of item : index of item
117
118 Make an index of the items in the list. The dictionary contains
119 the items in the list as the keys, and the index of the first
120 occurrence of the item as the value.
121
122 """
123 dict = {}
124 for i in range(len(l)):
125 if not dict.has_key(l[i]):
126 dict[l[i]] = i
127 return dict
128
130 """indexesof(l, fn) -> list of indexes
131
132 Return a list of indexes i where fn(l[i]) is true.
133
134 """
135 indexes = []
136 for i in range(len(l)):
137 f = fn(l[i])
138 if (not opposite and f) or (opposite and not f):
139 indexes.append(i)
140 return indexes
141
142 -def take(l, indexes):
143 """take(l, indexes) -> list of just the indexes from l"""
144 items = []
145 for i in indexes:
146 items.append(l[i])
147 return items
148
150 indexes = indexesof(l, fn, opposite=opposite)
151 return take(l, indexes)
152
153
154
155 try:
156 from clistfns import *
157 except ImportError:
158 pass
159