python中tuple/list/dict/set常用方法

一 元组

# 1 定义
tup1 = () # 空
tup2 = (0, ) # 注意，必须有分号
tup3 = (1, 2, 3, 4)

# 2 操作
# 2.1 合并
tup4 = tup2 + tup3 # (0, 1, 2, 3, 4)

# 2.2 长度
print len(tup4) # 5

# 2.3 切片
print tup4[0:4:2] # (0, 2)

# 3 遍历
for val in tup4:
print val
'''
0
1
2
3
4
'''

for i in range(len(tup4)):
print i, tup4[i]
'''
0 0
1 1
2 2
3 3
4 4
'''

二 列表

# 1 定义
list1 = [] # 空
list2 = [0]
list3 = [1, 2, 3, 4]

# 2 操作
# 2.1 合并
list4 = list2 + list3 # [0, 1, 2, 3, 4]

# 2.2 长度
print len(list4) # 5

# 2.3 切片
print list4[0:4:2] # [0, 2]

# 2.4 追加
list2.append(5) # [0, 5]
list2.append([6, 7]) # [0, 5, 6, 7]

# 2.5 移出
list2.pop(0) # [5], 不指定下标默认移出最后一项

# 3 遍历
for val in list4:
print val
'''
0
1
2
3
4
'''

for i in range(len(list4)):
print i, list4[i]
'''
0 0
1 1
2 2
3 3
4 4
'''

for i, item in enumerate(list4):
print i , item
'''
0 0
1 1
2 2
3 3
4 4
'''

三 字典

# 1 定义
dic1 = {} # 空
dic2 = {'one': 1}
dic3 = {'two': 2}

# 2 操作
# 2.1 合并
dic3.update(dic2) # {'one': 1, 'two': 2}
# 或者
# dic3 = dict(dic3, **dic2)

# 2.2 长度
print len(dic3) # 3

# 2.3 keys
print dic3.keys() # ['one', 'two']

# 2.4 values
print dic3.values() #[1, 2]

# 2.3 items
print dic3.items() # [('one', 1), ('two', 2)]

# 2.4 in
print 'one' in dic3 # True
print 1 in dic3 # False

# 2.5 pop
dic3.pop('one') # {'two': 2}

# 3 遍历
for val in dic3: # for val in dic3.iterkeys():
print val
'''
one
two
'''

for val in dic3.itervalues():
print val
'''
1
2
'''

for val in dic3.iteritems():
print val
'''
('one', 1)
('two', 2)
'''

for key, val in dic3.iteritems():
print key, val
'''
one 1
two 2
'''

四 集合

# 1 定义
set1 = set()
set2 = set([0,1]) #set([0, 1])
print set2

# 2 操作
# 2.1 长度
print len(set2) # 2

# 2.2 添加
set2.add(2) # 一项 ([0, 1, 2])
set2.update([3, 4]) # 多项 ([0, 1, 2, 3, 4])

# 2.3 移出
set2.remove(4) # ([0, 1, 2, 3])

# 2.4 集合运算
p1 = set([1, 2])
p2 = set([2, 3])
print p1 & p2 # 交集
'''
set([2])
'''
print p1 - p2 # 差集
'''
set([1])
'''
print p1 & p2 # 差集
'''
set([3])
'''
print p1 | p2 # 并集
'''
set([1, 2, 3])
'''

# 3 遍历
for val in set2:
print val
'''
0
1
2
3
'''