源自：https://www.cnblogs.com/wotoufahaiduo/p/10548182.html
一、python的数据类型
1.python的基本数据类型包括数值数据类型和字符串数据类型；基本数据类型的特点是不允许改变，如果改变基本数据类型的值，会导致内存的重新分配。
2.数值的相互转换函数
3.变量的三个属性
4.判断某个变量是否是某种类型实例
print(isinstance(3, float))
5.复数类型的使用
a = complex(2,2)
b = complex("3+2j")
print(a)
print(b)
print(a+b)
print(a-b)
print(a*b)
print(a/b)
(2+2j)
(3+2j)
(5+4j)
(-1+0j)
(2+10j)
(0.7692307692307692+0.15384615384615388j)
6.python的字符串类型不像Java可以与数值类型相加，如“str”+1会报错，但python支持字符串与数值相乘，表示将字符串重复多少次。
print("The life is short,i love python\n" * 3)
print("lower".upper())
print("UPPER".lower())
print(" hello python ".strip())
print("##hello python##!".strip("#!"))
print(len("hello"))
print("orange banana apple".split(" "))
print(" ".join(["orange","apple"
,"banana","peach"]))
print("good good study".startswith("go"))
print("day day up".endswith("up"))
print("Python is a nascent programming language.".count("p"))
print("Sometimes your whole life boils down to one insane move.".find("wh"))
print("moive".isdigit())
print("money".isalpha())
print("i declared".isspace())
7.Python的字符串最强大之处是切片操作
str = "Attitude determines altitude."
print(str[0:9])
print(str[0:20:3])
print(str[-5:-1])
8.Python的字符串可以用单引号，双引号，三引号表示，但字符串跨行时只能用三引号或反斜杠
str = '''Be
a
laborious
bee
'''
print(str)
str1 = "Be \
a \
hard-working \
man"
print(str1)
9.实现字符串反转
def strReverse1(str):
return str[::-1]
def strReverse2(str):
newList = list(str)
newList.reverse()
return "".join(newList)
print(strReverse1("python"))
print(strReverse2("python"))
二、输入输出
1、输入函数input()
myStr = input("请输入一个字符串：")
print(myStr)
a,b,c = eval(input("请输入3个数:"))
print(a,b,c)
2.输出函数 print()
print("i","am","studying","python")
print("i","am","studying","python",sep="#",end=" ")
print()
name = "jackson"
age = 22
salary = 5000.0
print("name:%s,age:%d,salary:%.3f" % (name,age,salary))
print("I like eating {} and {}".format("banana", "pear"))
print("His name is {name} and he is a {sex}".format(sex='male',name='judy'))
print("{1} can arm our {0}".format("brain","knowledge"))
print("The happiness rate of chinese citizen is up to {:.3f}".format(0.45))
print("The population of china is {:,d} million".format(1300))
三、集合数据类型
Python的集合数据类型包括列表，元组，字典，集合
1.列表
#四种遍历方式
fruits = ["orange","banana","pear","peach"]
for
item in fruits:
print(item,end=" ")
print()
for item in iter(fruits):
print(item,end=" ")
print()
for i,item in enumerate(fruits):
print(i,"===>",item,end=" ")
print()
for item in range(len(fruits)):
print(fruits[item],end=" ")
print()
#重复列表四次
print(fruits*4) #['orange', 'banana', 'pear', 'peach', 'orange', 'banana', 'pear', 'peach', 'orange', 'banana', 'pear', 'peach', 'orange', 'banana', 'pear', 'peach']
#列表连接
print(fruits+["pineapple","apple"])
#删除指定下标的元素，不提供参数则删除表尾元素
print(fruits.pop(2)) #['orange', 'banana', 'pear', 'peach', 'pineapple', 'apple']
#追加元素 append追加和extend追加有区别
#append追加的是列表
#extend追加的是元素
fruits.append(["Coconut"])
print(fruits) #['orange', 'banana', 'peach', ['Coconut']]
fruits.pop()
fruits.extend(["Coconut"])
print(fruits) #['orange', 'banana', 'peach', 'Coconut']
#列表反转
fruits.reverse()
print(fruits) #['Coconut', 'peach', 'banana', 'orange']
#指定位置插入
fruits.insert(2, "nothing")
print(fruits) #['Coconut', 'peach', 'nothing', 'banana', 'orange']
#删除列表切片
del fruits[1:3]
print(fruits) #['Coconut', 'banana', 'orange']
2.元组
myTuple1 = ("bird","plane","vehicle","subway")
#不能对单个元素重新赋值(报错)
#myTuple1[0] = "parrot"
#但可以对整个元组赋值
myTuple1 = ("python","c++","java")
print(myTuple1) #('python', 'c++', 'java')
#创建空元组
emptyTuple = ()
print(emptyTuple) #()
#注意创建一个元素的元组要在结尾加逗号
oneTuple = (1)
print(oneTuple) #1 不加逗号编译器会认为括号是进行算数运算，而不是创建元组
oneTuple = (1,)
print(oneTuple) #(1,)
#元组的取值
print(myTuple1[0]) #python
print(myTuple1[:]) #('python', 'c++', 'java')
print(myTuple1[:1]) #('python',)
print(myTuple1[len(myTuple1)-1:]) #('java',)
#元组的重复
print(myTuple1 *4) #('python', 'c++', 'java', 'python', 'c++', 'java', 'python', 'c++', 'java', 'python', 'c++', 'java')
#元组相加
print(myTuple1 + ("one","two","three")) #('python', 'c++', 'java', 'one', 'two', 'three')
3.字典
myDict = {"one":1,"two":343.33,"three":True}
print(myDict["one"
])
print("three" in myDict)
myDict["one"] = 100
print(myDict)
myDict.clear()
print(myDict)
4.集合
#以字符串创建set，自动去除重复元素
mySet = set("hello")
print(mySet) #{'o', 'l', 'e', 'h'}
#以list创建set
mySet1 = set(["a","m","e","o"])
print(mySet1) #{'o', 'a', 'm', 'e'}
#以map创建set，值为map的键
mySet2 = set({"name":1,"age":2})
print(mySet2) #{'name', 'age'}
#交集
print(mySet & mySet1) #{'e', 'o'}
#并集
print(mySet | mySet1) #{'l', 'a', 'e', 'h', 'm', 'o'}
#差集
print(mySet - mySet1) #{'l', 'h'}
#对称差分运算
print(mySet ^ mySet1) #{'l', 'a', 'h', 'm'}
四、强大的列表解析功能
import random
list1 = [random.randint(0,100) for i in range(0,10)]
for item in list1:
print(item,end=" ")
print()
list2 = [i*i for i in range(1,21)]
for num in list2:
print(num,end=" ")
list3 = [i for i in list2 if i % 2 == 0]
for num in list3:
print(num)
list4 = [[1,2,3,4],[5,6,7,8],[2,3,4
,5],[6,7,8,9]]
list5 = [[1,4,5,6],[2,1,3,4],[3,4,2,1],[7,8,2,1]]
print([row for row in list4])
print([list4[row][1] for row in range(len(list4))])
print([list4[i][i] for i in range(len(list4))])
print([list4[row][col] for row in range(len(list4)) for col in range(len(list4[row]))])
print([list4[row][col] + list5[row][col] for row in range(list4.__len__()) for col in range(list4[row].__len__())])
print([row for row in zip(*list4)])
students = ["jack","shirely","kangkang","mary"]
maxLen = max([len(item) for item in students])
print(maxLen)
maxStr = [temp for temp in students if len(temp) == maxLen]
print(maxStr)
五、内置函数
f = lambda ch:{"0":0,"1"
:1,"2":2,"3":3,"4":4,"5":5,"6":6,"7":7,"8":8,"9":9}[ch]
f1 = lambda ch:int(ch)
print(list(map(f,"322")))
def str2Decimal(x,y):
return x*10 + y
print(reduce(str2Decimal,map(f,"232")))
seq = range(2,51)
for i in seq:
f = lambda x : x == i or x % i
seq = list(filter(f,seq))
print(list(seq))
rules = lambda x:x.lower()
reles2 = lambda x:x["age"]
students = ["jack","Nacy","Kangkang","asia"]
aMap = [{"name":"kangknag","age":25},{"name":"ag","age":13},{
"name":"wnag","age":23}]
newlist = sorted(students, key=rules, reverse=False)
print(sorted(aMap,key=reles2))
print(newlist)
