直接引用，间接引用，字符格式化，转义字符的输出，f"{}"格式化输出

容器类型的变量，像list,dict都是间接引用

print('成功的概率为:%s'%(97))
运行结果：成功的概率为:97
print('成功的概率为:%s%%'%(97))
运行结果：成功的概率为:97%

例2：想输出｛｝号
x='egon'
y=18
print(f'name:｛x} age:{y}')
运行结果：name:egon age:18
print(f'name:{{x}} age:{{y}}')
运行结果：name:{x} age:{y}
print(f'name:{{{x}}} age:{{{y}}}')
运行结果：name:{egon} age:{18}

例3：格式化输出内的｛｝内的字符串可被当做表达式运行
f"{print('aaaaa')}"
运行结果：aaaaa

例4：“................................................egon................................................”的输出
x='egon'
y=18
print(f'name:{x} age:{y}')
print(f'name:{{x}} age:{{y}}')
print(f'name:{{{x}}} age:{{{y}}}')
f'{print("aaaaa")}'
print(f'{x:=<10}')
print(f'{x:=>10}')
print(f'{x:=^10}')

print(f'{x:.<10}')
print(f'{x:.>90}')
print(f'{x:.^100}')
运行结果：
name:egon age:18
name:{x} age:{y}
name:{egon} age:{18}
aaaaa
egon======
======egon
=egon=
egon......
......................................................................................egon
................................................egon................................................