python3：条件判断和循环语句

r囧r小猫 2023-08-17 17:31 168阅读 0赞

**条件判断**

# 条件判断 一定注意if 后面判断语句的冒号 #

# 完整语句 if: elif: else: #

age = 13
    if age>=18:
    	print("your age is ",age)
    	print("old")
    elif age>15:
    	print("15<age<=18",age)
    elif age>12:
    	print("12<age<=15",age)
    else:
    	print("your age is ",age)
    	print("young")

# if 判断条件简写 x是非零数值，非空字符串，非空list，就判断为True #

x=233
    if x:
    	print("True")

# input()返回的类型是str.需要强制转化为int() #

birth =int(input("birth:"))
    
    if birth <2000 :
    	print("00前")
    else:
    	print("00后")

\#循环 for in,把list 或者tuple中数据取出来,注意后面的冒号

# 如下为列表 list，其中name为一个变量，具体为列表中的元素 #

names =["Michal","Bob","Tracy"]
    for name in names:
        print(name)
    
    for mm in names:
        print(mm)
    
    for i in [1,2,3,4,"name1"]:
        print(i)
    
    for j in  (5,6,7,7,"sss",[1,2,3]):
        print(j)

# for x in xxx 就是把每个元素带入变量x，然后执行缩进块的语句 #

# 计算1 到10 的和 #

sum = 0   # 初始化sum
    for x in [1,2,3,4,5,6,7,8,9,10]:
        sum=sum+x # 每次sum值加x
    print(sum)

# range()函数，生成整数序列，再通过list函数转化为list #

# 计算1+2+3…+100的和. for in 一定记得加“” #

list1 = list(range(101)) # range(101) 只的是101个数。 0到100
    print(list1)
    sum = 0
    for x  in list1:
        sum=sum+x
    print(sum)

# in 后面可以直接用序列 range(101)是一个序列，可以转化为列表或者元组 #

sum = 0
    for x  in range(101):
        sum=sum+x
    print(sum)
    
    print(list(range(101))) # range()转化为list
    print(tuple(range(5))) #range()转化为tuple

# while函数 100 以内的奇数之和 #

sum = 0
    n =1
    while  n<100: # 只要条件满足，就不断循环
        sum=sum+n
        n=n+2
    print(sum)

# 对列表中名字依次 打印出 hello,xxx #

list= ["Michal","Tom","Jhon"]
    
    for name in list:
        name="hello,"+name
        print(name)

# break 循环中，提前退出循环 #

n=1
    while n<100:
        print(n)
        n=n+1
        if n>10:
            break  # break 跳出整个while循环

# 只想打印奇数 10 以内的奇数 #

# continue跳出本次循环 #

n = 0
    while n<10:
        n=n+1
        if n%2==0:
            continue
        print(n)