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Head First Python第3、4章学习笔记

Head First Python第3、4章学习笔记

作者: 剑胆琴心python | 来源:发表于2016-04-20 23:36 被阅读0次

    sketch.txt
    Man: Is this the right room for an argument?
    Other Man: I've told you once.
    Man: No you haven't!
    Other Man: Yes I have.
    Man: When?
    Other Man: Just now.
    Man: No you didn't!
    Other Man: Yes I did!
    Man: You didn't!
    Other Man: I'm telling you, I did!
    Man: You did not!
    Other Man: Oh I'm sorry, is this a five minute argument, or the full half hour?
    Man: Ah! (taking out his wallet and paying) Just the five minutes.
    Other Man: Just the five minutes. Thank you.
    Other Man: Anyway, I did.
    Man: You most certainly did not!
    Other Man: Now let's get one thing quite clear: I most definitely told you! #一行多个:
    Man: Oh no you didn't!
    Other Man: Oh yes I did!
    Man: Oh no you didn't!
    Other Man: Oh yes I did!
    Man: Oh look, this isn't an argument!
    (pause) #没有:
    Other Man: Yes it is!
    Man: No it isn't!
    (pause)
    Man: It's just contradiction!
    Other Man: No it isn't!
    Man: It IS!
    Other Man: It is NOT!
    Man: You just contradicted me!
    Other Man: No I didn't!
    Man: You DID!
    Other Man: No no no!
    Man: You did just then!
    Other Man: Nonsense!
    Man: (exasperated) Oh, this is futile!!
    (pause)
    Other Man: No it isn't!
    Man: Yes it is!


    ***=opne()
    ***.close()
    os.chdir()切换目录
    os.getcwd()查看当前目录
    readline()获取一行数据
    seek()回到文件起始位置
    split("*")以某个符号为分隔符,默认尽可能多的分割
    split("",1)分割一次
    无法更改的常量列表叫元组
    数据不符合期望格式ValueError
    数据无法正常访问IOError
    方法一:考虑每种异常
    import os
    if os.path.exists('sketch.txt'):    
        data = open('sketch.txt')
        for each_line in data:
            if not each_line.find(':') == -1:
                (role, line_spoken) = each_line.split(':',1)
                print(role),
                print('said:'),
                print(line_spoken),
        data.close()
    else:
        print("The file is missing!")
    方法二:增加异常处理
    try:
        data = open('sketch.txt')
        for each_line in data:
            try:
                (role, line_spoken) = each_line.split(':')
                print(role),
                print('said:'),
                print(line_spoken),
            except:
                pass
        data.close()
    except:
        print("The file is missing!")
    推荐使用异常处理,但是需要指定异常而不是所有异常统一处理
    

    为代码增加输出
    print("",file=*)
    open("*.out","w")#追加a,写和读w+
    读写都需要close()
    
    输出到屏幕
    man = []
    other = []
    try:
        data = open('sketch.txt')
        for each_line in data:
            try:
                (role, line_spoken) = each_line.split(':',1)
                line_spoken = line_spoken.strip() #删除空白
                if role == 'Man':
                    man.append(line_spoken)
                elif role == 'Other Man':
                    other.append(line_spoken)
            except ValueError:
                pass
        data.close()
    except IOError:
        print("The file is missing!")
    print(man)
    print(other)
    
    输出到文件
    man = []
    other = []
    
    try:
        data = open('sketch.txt',encoding='utf8')
        for each_line in data:
            try:
                (role, line_spoken) = each_line.split(':',1)
                line_spoken = line_spoken.strip()
                if role == 'Man':
                    man.append(line_spoken)
                elif role == 'Other Man':
                    other.append(line_spoken)
            except ValueError:
                pass
        data.close()  
    except IOError:
        print("The file is missing!")
        
    try:
        man_file=open('man_data.txt','w')
        other_file=open('other_data.txt','w')
        print(man,file=man_file)
        print(other,file=other_file)
        #man_file.close()modify:把close移到finally,保证关闭
        #other_file.close()   
    except IOError:
        print('File error.')
    finally:
        if 'man_file' in locals(): #增加文件不存在的判断
            man_file.close()
        if 'other_file' in locals():
            other_file.close()
    
    优化close&&日志版
    man = []
    other = []
    
    try:
        with open('sketch.txt',encoding='utf8') as data: #使用with替代finally
            for each_line in data:
                try:
                    (role, line_spoken) = each_line.split(':',1)
                    line_spoken = line_spoken.strip()
                    if role == 'Man':
                        man.append(line_spoken)
                    elif role == 'Other Man':
                        other.append(line_spoken)
                except ValueError:
                    pass  
    except IOError as Ierr:
        print("error:"+str(Ierr))
        
    try:
        with open('man_data.txt','w') as man_file:
            print(man,file=man_file)
        with open('other_data.txt','w') as other_file:
            print(other,file=other_file)  
    except IOError as err: #输出具体错误
        print('File error:'+str(err)) #BIF要求异常对象为字符串
    
    修改print_lol函数使输出的文件满足一定格式
    
    将输出的文件持久储存
    
    

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