循环（while,for,continue,break.函数注释）

循环

while循环

• 1.在一定条件下，重复做某件事件（代码）

• 2.while循环

• • 1.当条件表达式 == True 才执行循环内容

• • 2.循环的递增变量

          sumData = 0
          cnt = 1
          while cnt <101:
              sumData += cnt
              cnt += 1
          print(sumData)
    

• 3.死循环，不一定是bug，有优点，有用途

• 4.一般功能上的死循环都是结合一定条件下的 break

   	     while True:
   	         psw = input("请输入密码：")
   	         print("你在循环中，按q退出！")
   	         if psw == "q":
   	             break
  

for 循环

• 先体验下while

   			 alist = ["a", "b", "c", "d", "e", "f"]
   			 cnt = 0
   			 while cnt <6:
   			     print(alist[cnt])
   			     cnt += 1
  

					'''
					结果：
					a
					b
					c
					d
					e
					f
					'''

• 再看for 遍历

   		 alist = ["a", "b", "c", "d", "e", "f"]
   		 for i in alist:
   		     print(i)
  

‘’’

			结果：
			a
			b
			c
			d
			e
			f
			'''

• 打印1到10 range左含右不含

   	 for i in range (1,11):
   	     print(i)
  

‘’’

			1
			2
			3
			4
			5
			6
			7
			8
			9
			10
			'''

• 打印1到100的和

   			 sumData = 0
   			 for i in range (1,101):
   			     sumData += i
   			 print(sumData)
  

• break 跳出本层循环

   		 alist = ["a", "b", "c", "d", "e", "f"]
   		 for i in range(0,2):  #两次 0 1
   		     for name in alist:
   		         print(name)
   		         if name == "b":
   		             break
   		 print("over")
  

					# 结果：
					'''
					a
					b
					a
					b
					over
					'''

• continue 跳出本次循环

   		alist = ["a", "b", "c", "d", "e", "f"]
   		for i in range(0, 2):  # 两次 0 1
   		    for name in alist:
   		        if name == "b":
   		            continue
   		        print(name)
   		print("over")
  

							```
							# 结果
							'''
							a
							c
							d
							e
							f
							a
							c
							d
							e
							f
							over
							'''

• 函数内部注释

   			def func():
   			    "这个是函数的注释"
   			    print("函数")
  
  
   			print(func.__doc__)
   			#结果：这个是函数的注释