def modify_file(filename,old,new):

    import os

    with open(filename,'r',encoding='utf-8') as read_f,\

        open('.bak.swap','w',encoding='utf-8') as write_f:

        for line in read_f:

            if old in line:

                line=line.replace(old,new)

            write_f.write(line)

    os.remove(filename)

    os.rename('.bak.swap',filename)

modify_file('/Users/jieli/PycharmProjects/爬虫/a.txt','alex','SB')

def check_str(msg):

    res={

        'num':0,

        'string':0,

        'space':0,

        'other':0,

    }

    for s in msg:

        if s.isdigit():

            res['num']+=1

        elif s.isalpha():

            res['string']+=1

        elif s.isspace():

            res['space']+=1

        else:

            res['other']+=1

    return res

res=check_str('hello name:aSB passowrd:alex3714')

print(res)

def func(dac):

    if len(dac)>5

        print('真')

    else:

        print('假')

def func(dac):

    if len(dac)>2:

        dac=dac[0:2]

    return dac

print(func,[1,2,3,4])

def func(dac):

    return dac[::2]

print(func([1,2,3,4,5,6,7,8,9]))

dic = {"k1": "v1v1", "k2": [11,22,33,44]}

def mothod(dic):

    for key,val in dic.items():

        if len(val) > 2:

            dic[key] = val[:2]

    return dic

res = mothod(dic)

print(res)