函數練習：
1、寫函數，，用戶傳入修改的文件名，與要修改的內容，執行函數，完成批了修改操作

方式一：小文件修改
def change_file(file,old,new):
    with open(file,‘rt‘,encoding=‘utf-8‘) as read_f:
        data = read_f.read()
        data = data.replace(old,new)
    with open(file,‘wt‘,encoding=‘utf-8‘) as write_f:
        write_f.write(data)
    print(‘
 
success‘)
file_u = input(‘filename>>: ‘)
old_u = input(‘old>>: ‘)
new_u = input(‘new>>: ‘)
change_file(file_u,old_u,new_u)

方式二：大文件修改
def change_file(file,old,new):
    import os
    file1 = file+‘.swap‘
    with open(file,‘rt‘,encoding=‘utf-8‘) as read_f,            open(file1,‘wt
 
‘,encoding=‘utf-8‘) as write_f:
        for line in read_f:
            line = line.replace(old,new)
            write_f.write(line)
    os.remove(file)
    os.rename(file1,file)
    print(‘success‘)
file_u = input(‘filename>>: ‘)
old_u = input(‘old>>: ‘)
new_u = input(‘new>>: ‘)
change_file(file_u,old_u,new_u)
 

2、寫函數，計算傳入字符串中【數字】、【字母】、【空格] 以及 【其他】的個數

def str_count():
    str_u = input(‘請輸入>>: ‘)
    digit_count = 0
    alpha_count = 0
    space_count = 0
    other_count = 0
    for i in str_u:
        if i.isdigit():
            digit_count += 1
        elif i.isalpha():
            alpha_count += 1
        elif i.isspace():
            space_count += 1
        else:
            other_count += 1
    print(‘數字:%s 字母:%s 空格:%s 其他:%s‘ % (digit_count, alpha_count, space_count, other_count))
str_count()

3、寫函數，判斷用戶傳入的對象（字符串、列表、元組）長度是否大於5。

def func3(seq):
    if len(seq) > 5:
        return True
    else:
        return False
print(func3([1,2,3,4,5,6]))

4、寫函數，檢查傳入列表的長度，如果大於2，那麽僅保留前兩個長度的內容，並將新內容返回給調用者。

def func1(seq):
    if len(seq) > 2:
        return seq[0:2]
print(func1([1,2,3,4]))

5、寫函數，檢查獲取傳入列表或元組對象的所有奇數位索引對應的元素，並將其作為新列表返回給調用者。

def func2(seq):
    return seq[::2]
print(func2([1,2,3,4,5,6,7]))

6、寫函數，檢查字典的每一個value的長度, 如果大於2，那麽僅保留前兩個長度的內容，並將新內容返回給調用者。
dic = {"k1": "v1v1", "k2": [11, 22, 33, 44]}
PS:字典中的value只能是字符串或列表

dic = {"k1": "v1v1", "k2": [11, 22, 33, 44]}
def func6(seq):
    for k in seq:
        if len(seq[k]) > 2:
            seq[k] = seq[k][:2]
    return seq
print(func6(dic))

7、編寫認證功能函數，註意：後臺存儲的用戶名密碼來自於文件

def auth():
    name_inp = input(‘username>>: ‘).strip()
    pwd_inp = input(‘password>>: ‘)
    with open(‘db‘,‘rt‘,encoding=‘utf-8‘) as f:
        for line in f:
            line = line.strip(‘\n‘).split(‘:‘)
            if name_inp == line[0] and pwd_inp == line[1]:
                print(‘驗證成功‘)
                break
        else:
            print(‘用戶名或密碼錯誤‘)
auth()

8、編寫註冊功能函數，將用戶的信息儲存到文件中

def func8():
    name_inp = input(‘username>>: ‘).strip()
    pwd_inp = input(‘password>>: ‘)
    pwd_inp2 = input(‘password>>: ‘)
    if pwd_inp == pwd_inp2:
        print(‘註冊成功‘)
        with open(‘db‘,‘at‘,encoding=‘utf-8‘) as f1:
            f1.write(‘%s:%s\n‘ %(name_inp,pwd_inp))
    else:
        print(‘兩次密碼不一致‘)
func8()

9、編寫查看用戶信息的函數，用戶的信息是事先存放於文件中的

def func9():
    name = input(‘username>>: ‘).strip()
    with open(‘db‘,‘rt‘,encoding=‘utf-8‘) as f:
        for line in f:
            line = line.strip(‘\n‘).split(‘:‘)
            if name == line[0]:
                print(line)
                break
        else:
            print(‘用戶不存在‘)
func9()

明日默寫
1、修改文件的兩種方式

with open(‘db‘,‘rt‘,encoding=‘uf-8‘) as read_f:
    data = read_f.read()
    data = data.replace(‘old‘,‘new‘)
with open(‘db‘,‘wt‘,encoding=‘utf-8‘) as write_f:
    write_f.write(data)

import os
with open(‘db‘,‘rt‘,encoding=‘utf-8‘) as f2,        open(‘db.swap‘,‘wt‘,encoding=‘utf-8‘) as f3:
    for line in f2:
        f3.write(line.replace(‘old‘,‘new‘))
os.remove(‘db‘)
os.rename(‘db.swap‘,‘db‘)

2、註冊功能

name_inp = input(‘username>>: ‘).strip()
pwd_inp = input(‘password>>: ‘)
pwd_inp2 = input(‘password>>: ‘)
if pwd_inp == pwd_inp2:
    with open(‘db‘,‘at‘,encoding=‘utf-8‘) as f:
        f.write(‘%s:%s\n‘ %(name_inp,pwd_inp))

3、認證功能

name_inp = input(‘name>>: ‘).strip()
pwd_inp = input(‘password>>: ‘)
with open(‘db‘,‘rt‘,encoding=‘utf-8‘) as f:
    for line in f:
        line = line.strip(‘\n‘).split(‘:‘)
        if name_inp == line[0] and pwd_inp == line[1]:
            print(‘驗證通過‘)
            break
    else:
        print(‘用戶名或密碼錯誤‘)

python-code-04