错误和异常86

# while True: print('Hello World!')
print('异常有不同的类型，这些类型都作为信息的一部分打印出来：以下例子中的类型有ZeroDivisiongError，NameError和TypeError')
# print(10*(1/0))

# print(4+spam*3)

# print('2'+2)

print('Enter a number,if not give a exception')
while True:
    try:
        str = int(input('Please enter a number'))
        # break
    except ValueError:
        print('Oops,That was no valid number .Try again ')

print('except(RuntimeError,ValueError,TypeError,NameError)')
import sys
try:

    f = open('E:\foo.txt')
    s = f.readline()
    i = int(s.strip())
except OSError as err:
    print('OS error:{}'.format(err))

except ValueError:
    print('Could not conver a data to a integer.')
except:
    print('Unexpected error:',sys.exc_info()[0])
    raise

print('example2----------------------------------------------------------')
import sys
for foo in sys.argv[1:]:
    try:
        f = open(foo,'r')
    except IOError:
        print('cannot open',foo)
    else:
        print(foo,'has',len(f.readlines()),'lines')
        f.close()

print('heheda-------------------------------------')
def this_fails():
    x = 1/0
try:
    this_fails()
except ZeroDivisionError as err:
    print('Handling run-time error:',err)

print('hehda-------------------------------------')
raise NameError('HiThere')
try:
    raise NameError('HiThere')
except NameError:
    print('An exception flew by!')
    raise

print('hehda----------------------------------------------')
class MyError(Exception):
    def __init__(self,value):
        self.value = value
    def __str__(self):
        return repr(self.value)
try:
    raise MyError(2*2)
except MyError as e:
    print('My exception occurred,value:'.format(e.value))

print('hehda----------------------------------------------')


class MyError(Exception):
    def __init__(self, value):
        self.value = value

    def __str__(self):
        return repr(self.value)

try:
    raise MyError(2 * 2)
except MyError as e:
    print('My exception occurred,value:'.format(e.value))

raise MyError('oops!')