user =input('請輸入用戶名:')if'A'<= user[0]<='Z':count =0for x in user[1:]:ifnot('0'<= x <='9'or'a'<= x <='z'or'A'<= x <='Z'):print('不合法')breakelse:if'0'<= x <='9':count +=1else:if count ==0:print('不合法')else:print('合法')else:print('不合法')
輸入一個字符串,將字符串中所有的數字字符取出來產生一個新的字符串
例如:輸入**‘abc1shj23kls99+2kkk’** 輸出:'123992’
str2 ='abc1shj23kls99+2kkk'
result2 =''.join([x for x in str2 if'0'<= x <='9'])print(result2)
str3 ='a2h2klm12+'print(str3.upper())str3 ='a2h2klm12+'
new_str3 =''for x in str3:if'a'<= x <='z':new_str3 +=chr(ord(x)-32)else:new_str3 += x
print(new_str3)# 方法二print(''.join(chr(ord(x)-32)if x.islower()else x for x in str3))
str=input('請輸入一個小于1000的數字:')
str1 ='py1901'
str2 =''for x instr:iflen(str)==1:str2 ='00'+streliflen(str)==2:str2 ='0'+streliflen(str)==3:str2 =strelse:print('請輸入一個小于1000的數字:')print(str1 + str2)#方法二
num =9
num_str =str(num)
count =len(num_str)print('py1901'+'0'*(3-count)+num_str)
輸入一個字符串,統計字符串中非數字字母的字符的個數
例如: 輸入**‘anc2+93-sj胡說’** 輸出:4 輸入**’===’** 輸出:3
str=input('請輸入一個字符串:')
str1 =[]for x instr:if'0'<= x <='9'or'a'<= x <='z'or'A'<= x <='Z':passelse:str1 += x
print(len(str1))# 方法二
str1 ='anc2+93-sj胡說'
count =0for x in str1:ifnot(x.isdigit()or x.islower()or x.isupper()):count +=1print(count)
輸入字符串,將字符串的開頭和結尾變成’+’,產生一個新的字符串
例如: 輸入字符串**‘abc123’, 輸出’+bc12+’**
str=input('請輸入一個字符串:')
str1 =''.join([x for x instr[1:-1:]])print('+'+ str1 +'+')
str=input('請輸入一個字符串:')
str1 =[x for x inrange(len(str))]
str2 =''iflen(str1)%2!=0:str2 =str[len(str)//2]iflen(str1)%2==0:str2 =str[len(str)//2-1]+str[len(str)//2]print(str2)
寫程序實現字符串函數find/index的功能(獲取字符串1中字符串2第一次出現的位置)
例如: 字符串1為:how are you? Im fine, Thank you! , 字符串2為:you, 打印8
str1 ='how are you? Im fine, Thank you!'print(str1.find('you'))