Python基础知识一：字符串的方法 & 柳叶扉鸿

内容目录
"""
#   1、判断字符串是否以 XX 开头？得到一个布尔值:startswith

v1 = "叨逼叨的一天，烦死了"
result = v1.startswith("叨逼")
print(result)  # True

## 案例
# v1 = input("请输入住址：")
# if v1.startswith("北京市"):
#     print("北京人口")
# else:
#     print("非北京人口")
"""

"""
#   2、判断字符串是否以 XX 结尾？得到一个布尔值:endswith
v1 = "叨逼叨的一天，烦死了"
result = v1.endswith("烦死了")
print(result)  # 值为 True

# # 案例
# address = input("请输入地址：")
# if address.endswith('村'):
#     print("农业户口")
# else:
#     print("非农户口")
"""

"""
#   3、判断字符串是否为十进制数？得到一个布尔值：isdecimal
# v1 = "1238871"
# result = v1.isdecimal()
# print(result)  # True

## 案例,两个数相加。
# v1 = input("请输入值：")  # ”666“
# v2 = input("请输入值：")  # ”999“
# if v1.isdecimal() and v2.isdecimal():
#     data = int(v1) + int(v2)
#     print(data)
# else:
#     print("请正确输入数字！")

v1 = "123"
print(v1.isdecimal())  # T  rue,得到布尔值
v2 = "①"
print(v2.isdecimal())  # False

v3 = "123"
print(v3.isdigit())  # True
v4 = "①"
print(v4.isdigit())  # True
"""

"""
4、去除字符串两边的 空格、换行符、制表符，得到一个新字符串:strip、lstrip、rstrip

# data = input("请输入内容：")  # 武沛齐,武沛齐
# print(data)

# msg = " H e ll o 啊，树哥 "
# data = msg.strip()  # 将 msg 两边的空格去掉，得到“H e ll o 啊，树哥”
# print(data)
# data1 = msg.lstrip()  # 将 msg 左边的空格去掉，得到“H e ll o 啊，树哥 ”
# print(data1)
# data2 = msg.rstrip()  # 将 msg 右边的空格去掉，得到“ H e ll o 啊，树哥”
# print(data2)
# msg = " H e ll o 啊，树哥 "
# data = msg.strip("l")  # strip 只将 msg 两边的空格去掉，其他内部元素无效，得到“ H e ll o 啊，树哥 ”
# print(data)

# 补充 strip 用法：去除 空格、换行符、制表符。
# 案例
code = input("请输入 4 位验证码：")  # FB87
data = code.strip()
if data == "FB87":
    print('验证码正确')
else:
    print("验证码错误")
    
# 再补充：去除字符串两边指定的内容
# msg = "哥 H e ll o 啊，树哥"
# data = msg.strip("哥")
# print(data)  # 将 msg 两边的“哥”去掉，得到“H e ll o 啊，树”

# msg = "哥 H e ll o 啊，树哥"
# data = msg.lstrip("哥")
# print(data)  # 将 msg 左边的“哥”去掉，得到“H e ll o 啊，树哥”
# 
# msg = "哥 H e ll o 啊，树哥"
# data = msg.rstrip("哥")
# print(data)  # 将 msg 右边的“哥”去掉，得到“哥 H e ll o 啊，树”
"""

"""
5、字符串变大写，得到一个新字符串:upper

# msg = "my name is oliver queen"
# data = msg.upper()  # 将字符串变为大写，MY NAME IS OLIVER QUEEN
# print(data)

# # 案例
# code = input("请输入 4 位验证码：")  # FB88   fb88
# value = code.upper()  # 将字符变为大写
# data = value.strip()  # 将字符串的前后空格去除
# if data == "FB88":
#     print("验证码正确。")
# else:
#     print("验证码错误！")
#     
# # 注意事项
# code 的值"fb88 "
# value 的值"FB88 "
# data 的值"FB88"
"""

"""
# 6、字符串变小写，得到一个新字符串:lower

# msg = "My Name Is Oliver Queen"
# data = msg.lower()
# print(data)  # 将字符串变为小写，my name is oliver queen

# 案例
code = input("请输入 4 位验证码：")
value = code.lower().strip()
if value == "fb87":
    print('验证码正确')
else:
    print("验证码错误")
"""

"""
7、字符串内容替换，得到一个新的字符串:replace

data = "你是个好人，但是好人不合适我"
value = data.replace("好人", "坏人、贱人")
print(data)  # 你是个好人，但是好人不合适我
print(value)  # 你是个坏人、贱人，但是坏人、贱人不合适我

# 案例
video_file_name = "高清无码爱情动作片.mp4"
new_file_name = video_file_name.replace("mp4", "avi")
final_file_name = new_file_name.replace("无码", "步兵")
print(final_file_name)

# 案例
content = input("请输入评论信息")  # alex 是一个草包
content = content.replace("草", "**")
content = content.replace("尼玛", "**")
print(content)

char_list = ["cao", "草", "尼玛"]
content = input("请输入评论信息:")
for item in char_list:
    content = content.replace(item, "***")
print(content)

# char_list = ["草拟吗", "逗比", "二蛋", "钢球"]
# content = input("请输入评论信息")
# for item in char_list:
#     content = content.replace(item, "**")
# # AttributeError: 'str' object has no attribute 'repalce'
# print(content)
"""

"""
8、字符串切割，得到一个列表:split\rsplit

data = "武沛齐|root|wupeiqi@qq.com"
result = data.split("|")    # 以"|"为分隔
print(result)   # ['武沛齐', 'root', 'wupeiqi@qq.com']

# 案例：判断用户名密码是否正确
info = "武沛齐,root"  # 备注：字符串中存储了用户名和密码
user_list = info.split(",")
# print(user_list)    # ['武沛齐', 'root']
# print(user_list[0]) # 武沛齐
# print(user_list[1]) # root
user = input("请输入用户名：")
pwd = input("请输入密码：")
if user == user_list[0] and pwd == user_list[1]:
    print("登录成功，您的用户名密码正确！")
else:
    print("你的用户名或密码错误！")

# 扩展
data = "武沛齐|root|wupeiqi@qq.com"
v1 = data.split("|")
print(v1)  # ['武沛齐', 'root', 'wupeiqi@qq.com']
v2 = data.split("|", 1)
print(v2)  # ['武沛齐', 'root|wupeiqi@qq.com']
v3 = data.split("|", 2)
print(v3)  # ['武沛齐', 'root', 'wupeiqi@qq.com']
v4 = data.split("|", 0)
print(v4)  # ['武沛齐|root|wupeiqi@qq.com']

# 再扩展
data = "武沛齐,root,wupeiqi@qq.com"
v1 = data.rsplit(',')
print(v1)  # ['武沛齐', 'root', 'wupeiqi@qq.com']
v2 = data.rsplit(',', 1)
print(v2)  # ['武沛齐,root', 'wupeiqi@qq.com']

# 应用场景
file_path = "xxx/xxxx/xx.xx/xxx.mp4"
data_list = file_path.rsplit(".", 1)  # ["xxx/xxxx/xx.xx/xxx","mp4"]
print(data_list)
# data_list[0]
# data_list[1]

"""

"""
9|字符串拼接，得到一个新的字符串:join
data_list = ["alex", "是", "大烧饼"]
v1 = "_".join(data_list)    # alex_ 是 _ 大烧饼
print(v1)

"""

"""
11、字符串转换为字节类型:encode、decode

data = "嫂子"  # unicode，字符串类型

v1 = data.encode("utf-8")  # utf-8，字节类型
v2 = data.encode("gbk")  # gbk，字节类型

print(v1)  # b'\xe5\xab\x82 \xe5\xad\x90'
print(v2)  # b'\xc9\xa9 \xd7\xd3'

s1 = v1.decode("utf-8")  # 嫂子
s2 = v2.decode("gbk")  # 嫂子
print(s1)
print(s2)

v3 = data.encode("gb2312")
print(v3)   # b'\xc9\xa9\xd7\xd3'
"""

"""
# 12、将字符串内容居中、居左、居右展示:center、ljust、rjust

v1 = "王老汉"
data = v1.center(21, "-")
print(data)  # ---------王老汉---------

data = v1.ljust(21, "-")
print(data)  # 王老汉------------------

data = v1.rjust(21, "-")
print(data)  # ------------------王老汉
"""

# 13、帮助你填充 0：zfill
data = "alex"
v1 = data.zfill(10)
print(v1)  # 000000alex

# 应用场景：处理二进制数据
data = "101"  # "00000101"
v1 = data.zfill(8)
print(v1)  # "00000101"