No.9 else和with语句 一、else语句 1、与if搭配 语法：if (条件): 执行语句（条件为真时） else: 执行语句（条件为假时） 2、与循环语句for或while搭配 e.g.def showMaxFactor(num): count=num//2 while count>1: if num%count==0 print(%d最大的约数是%d’%(num.count)) break count-=1 else: print(’%d是素数！’%num) 3、与异常处理搭配 e.g. try: print(int(‘abc’)) except ValueError as reason: print(‘出错啦:’ + str(reason)) else: print(‘没有任何错误’) 二、with语句 e.g. try: with open(‘data.txt’,‘m’) as f: for each_line in f: print(each_line) except OSError as reason: print(‘出错啦：’+str(reason))
