Python 字符串的相关操作

s = "abcdefg"
s1 = s.capitalize() # 把首字母变成大写, 返回给你一个新的字符串
print(s)
print(s1)

s = "alex sb dsb wusir bigsb"
s2 = s.title() #标题,把字符串中的每个单词的首字母大写
print(s2)

s = "alex sb dsb bigsb"
s3 = s.upper()  #搜有字母变成大写字母(重点)
print(s3)

while True:
    content = input("请输入你要说的话,出入Q退出:")
    if content.upper() == "Q": #当需要忽略大小写的时候
        break
    print("你想对打野说",content)

# 验证码
verifyCode = "aEmn"
veri = input("请输入你的验证码(%s)" % verifyCode)
if veri.upper() == verifyCode.upper(): #忽略掉用户输入的大小写
    print("验证码是正确的")
else:
    print("验证码错误")

# 小写

s = "Alex Is Not A Good mAN"
s4 = s.lower()  #有问题的,对欧洲特殊文字是不识别的
print(s4)

s = "Alex Is Not A Good mAN"
s5 = s.casefold() #支持特殊文字
print(s5)

s = "wusir 昨天 Love 了 女神. guo fen 了"
print(s.swapcase()) # 大变小,小变大

# center()
s = "alex"
s6 = s.center(10,"_") #长度 用_填充
print(s6)

s = "      alex    is     sb     "
s7 = s.strip()  # 去掉左右两端的空白(空格,\t,\n)
print(s7)

# 应用
uname = input("请输入你的用户名:").strip() # 干掉用户的空格
upws = input("请输入你的密码:").strip()
if uname == "alex" and upws == "123":
    print("登陆成功")
else:
    print("登录失败")

s = "sbalexsbwusirsb"
print(s.strip("sb"))

# 字符串替换
s = "good alex good wusir good 大虾 good 胡辣汤"
s8 = s.replace("good","sb") #把s中的good替换成sb
print(s8)
s9 = s.replace(" ","")
print(s9)
s10 = s.replace("good","sb",2) #字符串替换2次
print(s10)

# 字符串切割
s = "alex_taibai_taihei_liang"
lst = s.split("_") # 切出来的结果会放在列表中, 刀如果把头了,
print(lst)

# 格式化输出
name = "alex"
age = 18
hobby = "wusir"
print("领导叫%s","今年%d","喜欢%s" % (name,age,hobby))
print("领导叫{}","今年{}","喜欢{}".format(name,age,hobby))
print("领导叫{1}","今年{0}","喜欢{2}".format(name,age,hobby))
print("领导叫{name}","今年{age}","喜欢{hobby}".format(name = name,age = age,hobby = hobby))

print(f"领导叫{name}","今年{age}","喜欢{hobby")

# 判断字符串是否以xxx开头
s = "java_python_区块链_大数据"
print(s.startswith("python")) # 判断xxx是否已xxx开头.

name = input("请输入你的名字:")  #张开 致青春
if name.startswith("张"):
    print("领钱")
else:
    print("不领钱")

# 以xxx结尾 endwith()

#数数
s = "alex is big sb"
print(s.count("i"))  #计数

# find 查找, 如果存在, 返回索引, 如果不存在返回-1   用这个
s = "滋滋冒油的猪蹄子"
print(s.find("冒油"))
  # index()如果找到了返回索引, 找不到, 报错
print(s.index("牛"))

s = "alex 昨天去wusir家了, 发现太白在里面"
print(s.isalpha()) #是否是由基本的文字组成,是否是由字母组成(包括中文)

# 判断是否是数字组成
s = "123456789"  #digit 数字 %d
print(s.isdigit())   #阿拉伯数字

s = "123456789一二三四壹仟叁佰"
print(s.isnumeric())

s = "我叫xxx,我喜欢bbb"
print(len(s)) #字符串长度

# 把一句话中的没一个字符拿到
s = "风扇哥门神灯神没吃饱"
# 用while循环,获取到没一个字符
i = 0 #索引
while i  < len(s):
    print(s[i])
    i += 1

# for循环来遍历字符串
# for:循环
# c:变量
# in:固定的
# s:你要遍历的内容
# for c in s: #把字符串s中的没一个元素拿到赋值给前面的c
#     print(c)

# for循环又一个先决条件, 必须是可迭代对象
# 遍历钱包
# 缺点: 无法看到字符的索引
'''
for 变量 in 可迭代对象:
    循环体(break, continu)
'''