"""
@Author       : 李晓华 (北京大学)
@Email        : chinapkulxh@pku.edu.cn
@Project      : 数据科学实战系列课程
@lecture      : Python预科班
@Organization : 光环国际 (http://aura.cn/)
"""

"""
    1，字符串 str
    
    2，定义：单引号，双引号，三单引号，三双引号！！！
    
    
"""

s1 = '光环国际'

print(s1)

s2 = "数据科学"

print(s2)

s3 = '''李晓华'''

print(s3)

s4 = """老师"""

print(s4)

print(print.__doc__)

s4 = 'Li Lei\'s girl friend'
s5 = "Li Lei's girl friend"
print(s4)
print(s5)

"""
    1，+  *
    

"""

s6 = "Hello, world."
print(s6 * 3)

"""
    1，索引
    
    IndexError: string index out of range

    
    2，切片
    
    
"""

s1 = "Hello"
print(s1)
print(s1[1])
print(s1[2])
print(s1[-3])
# print(s1[100])

print(s1[1] + s1[2])

print(s1[1:3])  # 1, 2  前闭后开

s2 = "234"
print(type(s2))
int1 = int(s2)
print(int1)
print(type(int1))

"""

    ValueError: invalid literal for int() with base 10: '234.0'
"""

s3 = "234.0"

print(int(float(s3)))

s1 = "   Hello, world.  "
print(s1)
print(s1.upper())
print(s1.lower())
print(s1.strip())
print(s1.lstrip())
print(s1.rstrip())

print(len(s1))

""""
    1，拼接字符串
    姓名：李晓华；性别：男；年龄：18.
    
"""

print("姓名：{}；性别：{}；年龄：{}".format("Tom", "女", 20))

"""
    1，编码
    

"""

s1 = "李晓华"
"""
    1，解铃还须系铃人
    
    UnicodeDecodeError: 'utf-8' codec can't decode byte 0xc0 in position 0: invalid start byte
    UnicodeDecodeError: 'gbk' codec can't decode byte 0x8e in position 8: incomplete multibyte sequence
"""

print(s1.encode(encoding="gbk"))
print(s1.encode(encoding="utf-8").decode(encoding="gbk"))