Python高级编程-13优化：解决方案
在一个有序list中进行二分查找
find.py
from bisect import bisect
def find(seq, el):
pos = bisect(seq, el)
if pos == 0 or (pos == len(seq) and seq[-1] != el):
return -1
return pos - 1
seq = [2, 3, 7, 8, 9]
find(seq, 9) # 4
find(seq, 10) # -1
find(seq, 0) # -1
find(seq, 7) # 2使用set保存无重复key的list
my_set.py
seq = ['a', 'a', 'b', 'c', 'c', 'd']
res = set(seq)
print res # set(['a', 'c', 'b', 'd'])deque
my_deque.py
from collections import deque
d = deque()
d.append('1')
d.append('2')
d.append('3')
print d # deque(['1', '2', '3'])
print len(d) # 3
print d[0] # 1
print d[-1] # 3
d.pop()
d.popleft()
print d # deque(['2'])
d.extendleft(['1', '0'])
d.extend(['3', '4', '5'])
print d # deque(['0', '1', '2', '3', '4', '5'])defaultdict
my_defaultdict.py
from collections import defaultdict
class Person(object):
def __init__(self, name, age):
self.name = name
self.age = age
def __str__(self):
return self.name
def __repr__(self):
return self.name
persons = [Person('bob', 20), Person('jack', 20), Person('mary', 22)]
persons_by_age = defaultdict(list)
for person in persons:
persons_by_age[person.age].append(person)
for k, v in persons_by_age.items():
print ':'.join([str(k), str(v)])
# 20:[bob, jack]
# 22:[mary]namedtuple
my_namedtuple.py
Bob = ('bob', 30, 'male')
print 'Representation:', Bob # Representation: ('bob', 30, 'male')
Jane = ('Jane', 29, 'female')
print 'Field by index:', Jane[0] # Field by index: Jane
for people in [Bob, Jane]:
print "%s is %d years old %s" % people
# bob is 30 years old male
# Jane is 29 years old female
from collections import namedtuple
Person = namedtuple('Person', 'name age gender')
print 'Type of Person:', type(Person) # Type of Person: