函数练习：
1、写函数，，用户传入修改的文件名，与要修改的内容，执行函数，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、写函数，计算传入字符串中【数字】、【字母】、【空格] 以及 【其他】的个数
def str_count(): str_u = input(‘请输入>>: ‘) 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(‘数字:%s 字母:%s 空格:%s 其他:%s‘ % (digit_count, alpha_count, space_count, other_count)) str_count()
3、写函数，判断用户传入的对象（字符串、列表、元组）长度是否大于5。
def func3(seq): if len(seq) > 5: return True else: return False print(func3([1,2,3,4,5,6]))
4、写函数，检查传入列表的长度，如果大于2，那么仅保留前两个长度的内容，并将新内容返回给调用者。
def func1(seq): if len(seq) > 2: return seq[0:2] print(func1([1,2,3,4]))
5、写函数，检查获取传入列表或元组对象的所有奇数位索引对应的元素，并将其作为新列表返回给调用者。
def func2(seq): return seq[::2] print(func2([1,2,3,4,5,6,7]))
6、写函数，检查字典的每一个value的长度, 如果大于2，那么仅保留前两个长度的内容，并将新内容返回给调用者。
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、编写认证功能函数，注意：后台存储的用户名密码来自于文件
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(‘验证成功‘) break else: print(‘用户名或密码错误‘) auth()
8、编写注册功能函数，将用户的信息储存到文件中
def func8(): name_inp = input(‘username>>: ‘).strip() pwd_inp = input(‘password>>: ‘) pwd_inp2 = input(‘password>>: ‘) if pwd_inp == pwd_inp2: print(‘注册成功‘) with open(‘db‘,‘at‘,encoding=‘utf-8‘) as f1: f1.write(‘%s:%s\n‘ %(name_inp,pwd_inp)) else: print(‘两次密码不一致‘) func8()
9、编写查看用户信息的函数，用户的信息是事先存放于文件中的
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(‘用户不存在‘) func9()
明日默写
1、修改文件的两种方式
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、注册功能
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、认证功能
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(‘验证通过‘) break else: print(‘用户名或密码错误‘)
原文：https://www.cnblogs.com/xujinjin18/p/9157965.html