为什么不写入文件?
问题描述:
所以我的代码:为什么不写入文件?
def logdata(x, y):
try:
f = open('multlog.txt', 'a')
f.write("{0:g} * {1:g} = {2:g}\n".format(x,y, (x*y)))
except ValueError:
f.write("Error, you tried to multiply by something that wasn't a number")
raise
finally:
f.close()
print("This is a test program, it logs data in a text file, 'multlog.txt'")
fn = input("Enter the first number you'd like to multiply by: ")
sn = input("Enter the second number you'd like to multiply by: ")
logdata(int(fn), int(sn))
而且我希望它做的事情,就是当它达到一个值误差,为它写入文件,“错误,你试图通过一些WASN繁殖'数字'。但是,如果用户输入字母(如“j”,如ValueError: invalid literal for int() with base 10: 'j'
),文件达到值错误,则不会写入文件!
答
至少存在两个问题:
- 该文件未打开在
except
块的写入(或追加)。 - 作为@DSM在评论所指出的,ValueError异常被当你调用
int()
我会改写成类似下面的例子提出。
如果您使用with
语句,则可以不使用finally
块。
def logdata(x, y):
with open('multlog.txt', 'a') as f:
try:
x = int(x); y = int(y)
f.write("{0:g} * {1:g} = {2:g}\n".format(x,y, (x*y)))
except ValueError:
f.write("Error")
print("This is a test program, it logs data in a text file, 'multlog.txt'")
fn = input("Enter the first number you'd like to multiply by: ")
sn = input("Enter the second number you'd like to multiply by: ")
logdata(fn, sn)
仍然没有做到这一点,即使我把F =开放(“multlog.txt”,“A”)中,除了块... – Billjk 2012-03-12 04:31:29
我认为错误是在其它方面:ValueError异常被引发在int()调用中,不在函数内部,所以不会被捕获。 – DSM 2012-03-12 04:31:44
谢谢,@DSM。我也注意到了。据此编辑答案。 – bernie 2012-03-12 04:36:25