# len：获取元组的长度 t = (1,2,3,4,5) len(t)
5
# max，min：最大最小值 print(max(t)) print(min(t))
5 1
# tuple：转化或建立元组 l = (1,2,3,4,5) t = tuple(l) print(t) t = tuple() print(t)
(1, 2, 3, 4, 5) ()
# count：计算指定数据出现的次数 t = (2,1,2,3,45,1,1,2,) print(t.count(2)) # index：求指定元素在元组中的索引位置 print(t.index(45)) # 若是须要的查找的数字是多个，则返回第一个 print(t.index(1))
3 4 1
# 两个变量交换值
a = 1
b = 3
print(a)
print(b)
print("*" * 20)
# java程序员会这么写：
c = a
a = b
b = c
print(a)
print(b)
print("*" * 20)
# python写法
a,b = b,a
print(a)
print(b)
1 3 ******************** 3 1 ******************** 1 3
# 集合的定义
s = set()
print(type(s))
print(s)
# 此时，大括号内必定要有值，不然定义出的是一个dict
s = {1,2,3,4,5,6,7}
print(type(s))
print(s)
<class 'set'>
set()
<class 'set'>
{1, 2, 3, 4, 5, 6, 7}
# 若是只是用大括号定义，则定义的是一个dict类型
d = {}
print(type(d))
print(d)
<class 'dict'>
{}
# 成员检测
# in，not in
s = {4,5,"i", "love", "you"}
print(s)
if "love" in s:
print("Yes")
if "haha" not in s:
print("Yes")
{'you', 4, 5, 'love', 'i'}
Yes
Yes
# for 循环
s = {4,5,"i", "love", "you"}
for i in s:
print(i)
you 4 5 love i
# 带有元组的集合遍历
s = {(1,2,3,), ("i", "love", "you"), (4,5,6)}
for k,m,n in s:
print(k, "--", m, "--", n)
for k in s:
print(k)
i -- love -- you
4 -- 5 -- 6
1 -- 2 -- 3
('i', 'love', 'you')
(4, 5, 6)
(1, 2, 3)
# 普通集合内涵
# 如下集合在初始化后自动过滤掉重复元素
s = {23,223,233,2,4,5,6,3,4,1,5,3}
print(s)
# 普通集合内涵
ss = {i for i in s}
print(ss)
{1, 2, 3, 4, 5, 6, 233, 23, 223}
{1, 2, 3, 4, 5, 6, 233, 23, 223}
# 带条件的集合内涵
sss = {i for i in s if i % 2 == 0}
print(sss)
{2, 4, 6}
# 多循环的集合内涵
s1 = {1,2,3,4}
s2 = {"i", "love", "you"}
s = {m*n for m in s2 for n in s1}
print(s)
s = {m*n for m in s2 for n in s1 if n == 2}
print(s)
{'you', 'youyou', 'love', 'lovelovelovelove', 'lovelovelove', 'lovelove', 'iii', 'youyouyouyou', 'ii', 'i', 'iiii', 'youyouyou'}
{'lovelove', 'youyou', 'ii'}
# len，max，min：跟其余基本的函数一致
s = {23,54,72,3,5,3,3,6,1,543}
print(len(s))
print(max(s))
print(min(s))
8 543 1
# set：生成一个集合
l = {1,2,3,4,5,4,3,2,1}
s = set(l)
print(s)
{1, 2, 3, 4, 5}
# add：向集合内添加元素
s = {1}
s.add(3)
print(s)
{1, 3}
# clear
s = {1,2,3,4,5}
print(id(s))
s.clear()
print(id(s))
# 结果代表clear函数是原地清空数据
1370773843528 1370773843528
# copy：拷贝
# remove：移除指定的值，直接改变原有值，若是要删除的值不存在，报错
# discard：移除集合中指定的值跟remove同样，可是若是要删除的话，不报错
s = {23,4,3,5,1,2,3}
s.remove(4)
print(s)
s.discard(1)
print(s)
print("*" * 20)
s.discard(100)
print(s)
s.remove(100)
print(s)
{1, 2, 3, 5, 23}
{2, 3, 5, 23}
********************
{2, 3, 5, 23}
---------------------------------------------------------------------------
KeyError Traceback (most recent call last)
<ipython-input-35-0113522ad176> in <module>
12 print(s)
13
---> 14 s.remove(100)
15 print(s)
KeyError: 100
# pop 随机移除一个元素
s = {1,2,3,4,5,6,7}
d = s.pop()
print(d)
print(s)
1
{2, 3, 4, 5, 6, 7}
# 集合函数
# intersection：交集
# difference：差集
# union：并集
# issubset：检查一个集合是否为另外一个子集
# issuperset：检查一个集合是否为另外一个超集
s1 = {1,2,3,4,5,6}
s2 = {5,6,7,8,9}
s_1 = s1.intersection(s2)
print(s_1)
s_2 = s1.difference(s2)
print(s_2)
s_3 = s1.issubset(s2)
print(s_3)
s_4 = s1.issuperset(s2)
print(s_4)
{5, 6}
{1, 2, 3, 4}
False
False
# 集合数学操做
s1 = {1,2,3,4,5,6}
s2 = {5,6,7,8,9}
# 如下不支持
s_1 = s1 - s2
print(s_1)
s_2 = s1 + s2
print(s_2)
{1, 2, 3, 4}
---------------------------------------------------------------------------
TypeError Traceback (most recent call last)
<ipython-input-45-fac787d752ea> in <module>
7 print(s_1)
8
----> 9 s_2 = s1 + s2
10 print(s_2)
TypeError: unsupported operand type(s) for +: 'set' and 'set'
# 建立 s = frozenset() print(type(s)) print(s)
<class 'frozenset'> frozenset()
# 字典的建立
# 建立空字典1
d = {}
print(type(d))
print(d)
# 建立空字典2
d = dict()
print(d)
# 建立有值的字典，每一组数据用冒号隔开，每一对键值对用逗号隔开
d = {"one":1, "two":2, "three":3}
print(d)
# 用dict建立有内容字典1
d = dict({"one":1, "two":2, "three":3})
print(d)
# 用dict建立有内字典2
# 利用关键参数
d = dict(one=1, two=2, three=3)
print(d)
#
d = dict( [("one",1), ("two",2), ("three",3)])
print(d)
<class 'dict'>
{}
{}
{'one': 1, 'two': 2, 'three': 3}
{'one': 1, 'two': 2, 'three': 3}
{'one': 1, 'two': 2, 'three': 3}
{'one': 1, 'two': 2, 'three': 3}
字典中的数据每一个都有键值对组成，即kv对java
# 访问数据
d = {"one":1, "two":2, "three":3}
# 注意访问格式
# 中括号内是键值
print(d["one"])
d["one"] = "eins"
print(d)
# 删除某个操做
# 使用del操做
del d["one"]
print(d)
1
{'one': 'eins', 'two': 2, 'three': 3}
{'two': 2, 'three': 3}
# 成员检测：in，not in
# 成员检测检测时的key内容
d = {"one":1, "two":2, "three":3}
if 2 in d:
print("value")
if "two" in d:
print("key")
if ("two,2") in d:
print("kv")
key
# 遍历在python2 和 3 中区别比较大，代码不通用
# 按key值使用for循环
d = {"one":1, "two":2, "three":3}
# 使用for循环，直接按keu值访问
for k in d:
print(k, d[k])
# 上述代码能够改写以下
for k in d.keys():
print(k, d[k])
# 只访问字典的值
for v in d.values():
print(v)
# 注意如下特殊用法
for k,v in d.items():
print(k, "--", v)
one 1 two 2 three 3 one 1 two 2 three 3 1 2 3 one -- 1 two -- 2 three -- 3
d = {"one":1, "two":2, "three":3}
# 常规字典生成式
dd = {k:v for k,v in d.items()}
print(dd)
# 加限制条件的字典生成式
dd = {k:v for k,v in d.items() if v % 2 == 0}
print(dd)
{'one': 1, 'two': 2, 'three': 3}
{'two': 2}
# 通用函数：len，max，min，dict
# str(字典)：用于返回字典的字符串格式
d = {"one":1, "two":2, "three":3}
print(str(d))
{'one': 1, 'two': 2, 'three': 3}
# clear：清空字典
# items：返回字典的键值对组成的元组格式
d = {"one":1, "two":2, "three":3}
i = d.items()
print(type(i))
print(i)
<class 'dict_items'>
dict_items([('one', 1), ('two', 2), ('three', 3)])
# keys：返回字典的键组成的一个结构 k = d.keys() print(type(k)) print(k)
<class 'dict_keys'> dict_keys(['one', 'two', 'three'])
# values：同理，一个可迭代的结构 v = d.values() print(type(v)) print(v)
<class 'dict_values'> dict_values([1, 2, 3])
# get：根据指定键返回相应的值，好处是，能够生成默认值
d = {"one":1, "two":2, "three":3}
print(d.get("oner"))
# get默认值是None，能够设置
print(d.get("one", 100))
print(d.get("one33", 100))
print(d['on333'])
None
1
100
---------------------------------------------------------------------------
KeyError Traceback (most recent call last)
<ipython-input-86-f8c01a58018e> in <module>
8 print(d.get("one33", 100))
9
---> 10 print(d['on333'])
KeyError: 'on333'
# fromkeys：使用指定的序列做为键，使用一个值做为字典的全部键的值 l = ["eins", "zwei", "dree"] # 注意fromkeys两个参数的类型 # 注意fromkeys的调用主体 d = dict.fromkeys(l, "hahahahaha") print(d)
{'eins': 'hahahahaha', 'zwei': 'hahahahaha', 'dree': 'hahahahaha'}