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  • [Head First Python]4. summary

    1- strip()方法可以从字符串去除不想要的空白符

    (role, line_spoken) = each_line.split(":", 1)
    line_spoken = line_spoken.strip()

    2- print() BIF的file参数控制将数据发送/保存到哪里

    print(...)
        print(value, ..., sep=' ', end='
    ', file=sys.stdout, flush=False)
        
        Prints the values to a stream, or to sys.stdout by default.
        Optional keyword arguments:
        file:  a file-like object (stream); defaults to the current sys.stdout.
        sep:   string inserted between values, default a space.
        end:   string appended after the last value, default a newline.
        flush: whether to forcibly flush the stream.
    if indent:
        for tab_stop in range(level):
            print("	",end='', file = fn)
    print(each_item, file = fn)

    3- 会向except组传入一个异常对象,并使用as关键字赋至一个标示符

    except IOError as err:
        print('file error' + str(err))
    except pickle.PickleError as perr:
        print('pickle err' + str(perr))

    4- str() BIF可以用来访问任何数据对象的串表示

    5- locals() BIF返回当然作用域中的变量集合 

    1 try:
    2     data = open ('missing')
    3     print(data.read_line(),end = '')
    4 except IOError as err:
    5     print('file error' + str(err))
    6 finally:
    7     if 'data' in locals():
    8         data.close()
    1 try:
    2     with open ('missing.txt','w') as data:
    3         print("this is test",file = data)
    4 except IOError as err:
    5     print('file error' + str(err))

    6- in 操作符用来检查成员关系

    7- + 连接两个字符串

    8- with 会自动处理所有已打开文件的关闭工作,即使出现异常也不例外, with也使用as关键字

    9- sys.stdout 是python中"标准输出", 可以从标准库的sys模块访问

    10- 标准库的pickle模块, 将python数据对象保存到磁盘及从磁盘恢复

    11- pickle.dump() 函数将数据保存到磁盘

    1 try:
    2     with open('man.out', 'wb') as man_out, open('other.out','wb') as other_out:
    3         pickle.dump(man, man_out) 
    4         pickle.dump(other, other_out)

    12- pickle.load() 函数从磁盘恢复数据

    1 new_man = []
    2 try:
    3     with open('man.out', 'rb') as man_file:
    4         new_man = pickle.load(man_file) 
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  • 原文地址:https://www.cnblogs.com/galoishelley/p/3794270.html
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