import timedef main():f = Nonetry:# 一次性读取整个文件内容print('# 一次性读取整个文件内容')with open('beatbox.txt', 'r', encoding='utf-8') as f:print(f.read())# 通过for-in循环逐行读取print('# 通过for-in循环逐行读取')with open('beatbox.txt', 'r') as f:for line in f:print(line, end='')time.sleep(0.5)# 读取文件按行读取到列表中print('# 读取文件按行读取到列表中')with open('beatbox.txt', 'r') as f:lines = f.readlines()print(lines)except FileNotFoundError:print('Can not open file.')except LookupError:print('Specify unknow encoding.')  # 指定未知编码except UnicodeDecodeError:print('Reading file decoding failed.')  # 读取文件时解码错误finally:if f:f.close()if __name__ == '__main__':main()

from math import sqrtdef is_prime(n):"""判断素数的函数"""assert n > 0  # if not n > 0: raise AssertionError()for factor in range(2, int(sqrt(n)) + 1):if n % factor == 0:return Falsereturn True if n != 1 else Falsedef main():filenames = ('a.txt', 'b.txt', 'c.txt')fs_list = []try:for filename in filenames:fs_list.append(open(filename, 'w', encoding='utf-8'))for number in range(1, 10000):if is_prime(number):if number < 100:fs_list[0].write(str(number) + 'n')elif number < 1000:fs_list[1].write(str(number) + 'n')else:fs_list[2].write(str(number) + 'n')except IOError as ex:print(ex)print('写文件时发生错误！')finally:for fs in fs_list:fs.close()print('操作完成！')if __name__ == '__main__':main()

# 读写二进制文件
def main():try:with open('test1.png', 'rb') as f1:data = f1.read()print(type(data))with open('test2.png', 'wb') as f2:f2.write(data)except FileNotFoundError as e:print('指定文件无法打开。')except IOError as e:print('读写文件出现错误。')finally:print('程序执行结束')if __name__ == '__main__':main()

# 使用内置的语法范式代替try/except
# for循环处理了StopIteration异常## should not
# 1.
try:f = open('a.txt')print(f.read())
except IOError as e:print(e)
finally:print('done')
# 2.
class Test:name = 0
try:test = Test()name = test.name  # 不确定我能不能得到name属性
except AttributeError:name = 'default'## should
# 1`.
with open('a.txt') as f:print(f.read())
# 2.
test = Test()
name = getattr(test, 'name', 'default')