python包含以下几种基本数据类型:
(1)不可变数据
NoneType、bool、str(字符串)、int(整型)、float(浮点型)、tuple(元组)
(2)可变数据
list(列表)、dict(字典)、set(集合)
a=None b=True c = 'hi' d = 1 e = 1.1 f = (1, 2, 3) f1 = tuple((1, 2, 3)) g = [1, 2, 3] g1 = list([1, 2, 3]) h = {'a': 1, 'b': '2', 'c': [3, 4]} h1 = dict({'a': 1, 'b': '2', 'c': [3, 4]}) i = set((1, 2, 3)) print('type(a)=>', type(a)) print('type(b)=>', type(b)) print('type(c)=>', type(c)) print('type(d)=>', type(d)) print('type(e)=>', type(e)) print('type(f)=>', type(f)) print('type(g)=>', type(g)) print('type(h)=>', type(h)) print('type(i)=>', type(i)) # type(a)=> <class 'NoneType'> # type(b)=> <class 'bool'> # type(c)=> <class 'str'> # type(d)=> <class 'int'> # type(e)=> <class 'float'> # type(f)=> <class 'tuple'> # type(g)=> <class 'list'> # type(h)=> <class 'dict'> # type(i)=> <class 'set'>
(1)列表遍历
data = [(1, 2), (3, 1), (2, 3)] for index, item in data: print(index, ":", item) # 1 : 2 # 3 : 1 # 2 : 3
(2)列表排序:
data = [(1, 2), (3, 1), (2, 3)] data = sorted(data, key=lambda x: x[1], reverse=True) print(data) # [(2, 3), (1, 2), (3, 1)]
(3)字典遍历
data = dict({'a': 1, 'b': '2', 'c': [3, 4]}) for k, v in data.items(): print(k, '=>', v) # a => 1 # b => 2 # c => [3, 4]
(4)字典合并
data1 = {'a': 1, 'b': 2} data2 = {'b': 3, 'c': 4} #方法一 data1.update(data2) print(data1) # {'a': 1, 'b': 3, 'c': 3} #方法二 result={**data1,**data2} print(result) # {'a': 1, 'b': 3, 'c': 3}
(5)字典setdefault方法
data = {'a': 1, 'b': [1,2]} x = data.setdefault('b', []) x.append(3) x = data.setdefault('c', []) x.append(4) print(data) # {'a': 1, 'b': [1, 2, 3], 'c': [4]}