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输入一个字符串，打印所有奇数位上的字符(下标是1，3，5，7…位上的字符)
例如: 输入'abcd1234 ' ** 输出'bd24'**
str1 = input()
for index, each in enumerate(str1):
if index & 1:
print(each, end='')
- 输入用户名，判断用户名是否合法(用户名长度6~10位)
def validate_username(username: str) -> bool:
if isinstance(username, str) and 6 <= len(username) <= 10:
return True
return False
-
输入用户名，判断用户名是否合法(用户名中只能由数字和字母组成)
例如: 'abc' — 合法 '123' — 合法 ‘abc123a’ — 合法
def validate_username(username: str) -> bool:
if not isinstance(username, str):
return False
for each in username:
if not (48 <= ord(each) <= 57 or 65 <= ord(each) <= 90 or 97 <= ord(each) <= 122):
return False
return True
-
输入用户名，判断用户名是否合法(用户名必须包含且只能包含数字和字母，并且第一个字符必须是大写字母)
例如: 'abc' — 不合法 '123' — 不合法 'abc123' — 不合法 'Abc123ahs' — 合法
def validate_username(username: str) -> bool:
if not isinstance(username, str):
return False
isCap = True if len(username) > 0 and 65 <= ord(username[0]) <= 90 else False
hasNum = False
hasWord = False
for each in username:
if not (48 <= ord(each) <= 57 or 65 <= ord(each) <= 90 or 97 <= ord(each) <= 122):
return False
elif 48 <= ord(each) <= 57 and not hasNum:
hasNum = True
elif (65 <= ord(each) <= 90 or 97 <= ord(each) <= 122) and not hasWord:
hasWord = True
return (isCap and hasNum and hasWord)
-
输入一个字符串，将字符串中所有的数字字符取出来产生一个新的字符串
例如：输入'abc1shj23kls99+2kkk' 输出：'123992'
def extract_num(s: str) -> str:
if not isinstance(s, str) and len(s) > 0:
return None
num_str = []
for each in s:
if 48 <= ord(each) <= 57:
num_str.append(each)
return ''.join(num_str)
-
输入一个字符串，将字符串中所有的小写字母变成对应的大写字母输出 (用upper方法和自己写算法两种方式实现)
例如: 输入**'a2h2klm12+' ** 输出 'A2H2KLM12+'
def upper(username: str) -> str:
if not isinstance(username, str) and len(username) > 0:
return None
new_str = []
for each in username:
asc = ord(each)
if 97 <= asc <= 122:
asc -= 32
new_str.append(chr(asc))
return ''.join(new_str)
-
输入一个小于1000的数字，产生对应的学号
例如: 输入'23'，输出'py1901023' 输入'9', 输出'py1901009' 输入'123'，输出'py1901123'
def generate_id(num: int) -> str:
if not isinstance(num, int) and 0 <= num < 1000:
return None
return 'py1901' + str(num).zfill(3)
-
输入一个字符串，统计字符串中非数字字母的字符的个数
例如: 输入'anc2+93-sj胡说' 输出:4 输入'===' 输出:3
def count(string: str) -> int:
if not isinstance(string, str):
return False
count = 0
for each in string:
if not (48 <= ord(each) <= 57 or 65 <= ord(each) <= 90 or 97 <= ord(each) <= 122):
count += 1
return count
-
输入字符串，将字符串的开头和结尾变成'+'，产生一个新的字符串
例如: 输入字符串'abc123', 输出'+bc12+'
def process_str(string: str) -> str:
if not isinstance(string, str):
return None
new_str = list(string)
new_str[0] = '+'
new_str[len(new_str) - 1] = '+'
return ''.join(new_str)
- 输入字符串，获取字符串的中间字符
例如: 输入'abc1234' 输出:'1' 输入'abc123' 输出'c1'
def extract_middle_str(string: str) -> str:
if not isinstance(string, str):
return None
if len(string) <= 2:
return string
i = len(string) // 2
middle_str = string[i] if len(string) & 1 else string[i-1: i+1]
return middle_str
- 写程序实现字符串函数find/index的功能(获取字符串1中字符串2第一次出现的位置)
例如: 字符串1为:how are you? Im fine, Thank you! , 字符串2为:you, 打印8
def find(str1: str, str2: str) -> int:
if not isinstance(str1, str) and not isinstance(str2, str):
return None
list1 = list(str1)
list2 = list(str2)
for index in range(len(list1)):
for ch1, ch2 in zip(list1[index::], list2):
if ch2 != ch1:
break
else:
return index
- 获取两个字符串中公共的字符
例如: 字符串1为:abc123, 字符串2为: huak3 , 打印:公共字符有:a3
def public_str(str1: str, str2: str) -> str:
if not isinstance(str1, str) and not isinstance(str2, str):
return None
list1 = set(str1)
list2 = set(str2)
return ''.join(list1 & list2)