for语句格式：for 变量名 in 集合: 语句逻辑：按顺序取“集合”中的每个元素，赋值给“变量”，再去执行语句，如此循环往复，直达取完“集合”中的元素截止 for i in [1, 2, 3, 4, 5]: print(i) range([start,] end [,step]) # 函数 列表生成器start 默认为0 step 默认为1 功能：生成数列 a = range(10)print(a)for x in range(10): print(x)for y in range(2, 20, 3): #3表示步长 print(y) # 同时遍历下标和元素 for index , m in enumerate([1, 2, 3, 4, 5]): #index, m = 下标， 元素 print(index, m) # enumerate 枚举器sum = 0for i in range(1,101): sum = sum +iprint(sum)
二、while循环
while 语句
格式：
while 表达式：
语句
逻辑：表达式为真，执行“语句”
num = 1while num <= 5:
print("num = %d ",%(num))
num += 1
例1# 计算1+2+3.。。。。+100
sum = 1
num = 1
while num <= 100:
sum = sum + num
num +=1print("sum = %d"% (sum))
例2# 打印每一个字符
str = " sunck is a good man "
index = 0while index < len(str):
print("str[%d] = %s" % (index, str[index]))
index += 1
例3#打印出所有三位数中的水仙花数
num = 99
while num<999:
a = num % 10
b = (int(num /10)) % 10
c = int(num / 100)
d = a**3 + b**3 +c**3
if d == num :
print ("num = %d" %(num))
num += 1
例4#告诉我五位数中有多少个回文数
num1 = 10000
i = 0
while num1<100000:
a = num1//10000 # 求高位数
b = num1 % 10 # 求低位数
if a == b:
c = num1 // 1000 % 10
d = num1 //10 %10
if c == d:
i += 1
num1 += 1
print ("回文数个数是：%d 个"%(i))
例6#从控制台输入一个数，判断是否为质素
num = int(input("请输入一个数："))
a = 1
i = 0
while a <= num:
b = num /a
if b == num // a:
i += 1
a += 1
if i > 2:
print("%d不是质数%(num)")
break
if i == 2:
print("%d是质数"%(num))
例7#从控制台输入一个数，分解质因数
num = int(input("输入一个数"))
i = 2
while num != 1:
if num % i == 0:
print(i)
num //= i
else :
i += 1
例8#从控制台输入一个字符串，返回这个字符串中有多少个单词
str = input()#lasdf***aasf aasge age a g easr
str1 = str.strip()
index = 0
count = 0
while index < len(str1):
while str1[indx] != " ":
index += 1
if index == len(str1):
break
count += 1
if index == len(str1):
break
while str1[index] == " ":
index += 1print(count)
例9#从控制台输入一个字符串，打印出这个字符串中所有数字字符的和
str = input("请输入一串字符串")
index = 0
sum = 0
while index < len(str):
if str[index ] >= "0" and str[index] <= "9":
sum += int(str[index])
index += 1print("sum = %d"%(sum))
# 字符串比较大小
# 从第一个字符开始比较,谁的ASCII值大谁就大，如果相等回比较下一个
# 字符的ASCII值大小，那么谁的值大谁就大三、死循环
# 死循环:表达式永远为真的循环
while 1:
print("sunck is a good man !")四、else语句
while 表达式:
语句1
else：
语句2
# 逻辑：在条件语句(表达式)为False时执行else中的语句
a =1
while a<= 3:
print ("sunck is a good man!")
a += 1
else :
print("very very good")print("you are right")五、循环中断语句
break语句：
作用：跳出 for 和 while 循环
注意：只能跳出距离他最近的那一层循环
for i in range(10):
print(i)
if i == 5: #结束循环
break
num = 1
while num <= 10:
print(num)
if num == 3:
break
num += 1
else:
print(num)
注意：循环语句可以有else语句，break导致循环结束，不会执行else语句
continue 语句作用：跳过当前循环中的剩余语句，然后继续下次循环
注意：跳过距离最近的循环，然后进入下次循环
for i in range(10):
print(i)
if i == 3:
continue
print("*")
print("&")
num = 0
while num < 10:
print(num)
if num == 3:
num += 1
continue
num += 1
print("*")
print("&")六、实例
#小甲鱼import random
secret = random.randint(1,10)print("----------小甲鱼---------")
tempt = input ("please input a number :")
guess = int (tempt)while guess != secret:
tempt = input("从新输入数字：")
guess = int(tempt) if guess == secret: print("你是小甲鱼心中的蛔虫吗？") print("哼，猜中了也没有奖励") else : if guess > secret: print("哥，大了，大了") else : print("嘿 ，小了，小了")print("不玩了，不玩了")#小甲鱼print("欢迎进入此游戏")
guess = input("please input a number")
guess = int(guess)if (guess >= 6): print("大了")
guess = input("please input a number once again")
guess = int(guess)if (guess <=4): print("小了")
guess = input("please input a number once again")
guess = int(guess)while True : if guess == 5: print("哇哦，你厉害，猜对了") print("不玩了") break
else : print("游戏没意思，不玩了") breakdef MyFirstFunction(): print("欢迎进入游戏")
number = input("input a number")
number = int (number) while number > 0: print ("恭喜您，中奖了")
number= number-1MyFirstFunction()
list=[1,2,3,4,5,5]for i in list: print(i)# 判断一个三位数是否为水仙花数num = int (input(" 请输入一个三位数"))
a = num % 10
b = num //10 %10
c = num // 100
if num == pow (a,3)+pow(b,3)+pow(c,3):
print ("yes")
else :
print ("no")# 判断是否为回文数num = int(input ("请输入一个五位数"))
a = num % 10 #求低位数，用求余数
b = num //10000 #求高位用整除
if a!=b:
print("no")#比较三个数中的最大值num1 = int(input())
num2 = int(input())
num3 = int(input())
max =num1
if max < num2:
max = num2
else:
if max < num3:
max = num3
print(max) #判断一个年份是否为闰年year = int (input("请输入一个年份:"))
if year % 400 == 0 or (year % 100 != 0 and year % 4 == 0):
print("是闰年")
else :
print ("不是闰年") # 找出一组数中第二大的数listNum = []
num = 0while num < 5:
val = int(input())
listNum.append(val)
num += 1print(listNum)# 升序排序listNum.sort()
count = listNum.count(listNum[len(listNum) - 1])
c = 0while c < count:
listNum.pop()
c += 1print(listNum[len(listNum) - 1])#打印99乘法表for a in range(10):
for b in range(10):
c = a * b
print("%d * %d = %d"%(a, b,c))
if a == b:
break
print("\n")#输入两个数，求着两个数的最大公约数a = int(input())
b = int (input())
min = min (a, b)import mathfor i in range(1,min): for i in range(1, min):
c = a % i
d = b % i if c == 0 and b ==0:
d = 1
d = d * iprint(d)
原文：http://blog.51cto.com/13711245/2107059