笔记4_分之循环与逻辑表达式2
#分支语句 x=0 if x<0: print("aa") elif x==0: print("bb") else: print("cc") 1:逻辑表达式 and 逻辑与 or 逻辑或 not 逻辑非 #循环语句 while a<10: print('a=%i'%a) a=a+1 #a += 1 a++不对 #for语句 >>> for char in 'hello': print char >>> for ii in range(10): #输出0~9 print ii >>> for ii in range(1,11): #输出1到10 print ii >>> for ii in range(1,11,2): #range([start ,] stop [, step]) print(ii) #break和continue >>> for ii in range(1,11): print(ii) if ii==5: break #循环+else:循环完成,进入else number = int(raw_input('输入一个自然数')) factor = number/2 while factor>1: if number%factor ==0: print number,'具有因子',factor,'不是素数' break factor = factor-1 else: print number,'是素数' #pass空操作 for x in range(10): pass #什么也不做,有例外时处理