Python入门day09(输出变量的方式,编码解码,isinstance)

输出变量的方法

#%s字符串 %d整数 %f浮点数
#也可用直接用%s

a = 1.2
b = 21
c = 'zyt'

#1.用%s,%d,%f形式
print("I am %s,my age is %d,i have %f"%(c,b,a))
#I am zyt,my age is 21,i have 1.200000
print("I am %s,my age is %s,i have %s"%(c,b,a))
#I am zyt,my age is 21,i have 1.2

#2.用{}.format形式
print("I am {},my age is {},i have {}".format(c,b,a))
#I am zyt,my age is 21,i have 1.2
print("I am {s1},my age is {s2},i have {s3}".format(s3 = a,s2 = b,s1 = c))
#I am zyt,my age is 21,i have 1.2

#3.用f"{}"形式
print(f"I am {c},my age is {b},i have {a}")
#I am zyt,my age is 21,i have 1.2

编码解码

#字符串编码解码：
#str:unicode =>只能在Python内存中存在，不能网络传输和硬盘保存
#bytes:bytes => 经过编码后的字符串，适合网络传输和硬盘保存
#unicode => bytes 经过指定的编码方式
#bytes => unicode 通过和bytes原来的解码方式一致的解码方式

#字符串编码解码
a = 'hello'
b = a.encode('utf-8')
c = b.decode('utf-8')

print(type(b))
print(b)
# <class 'bytes'>
# b'hello'

print(type(c))
print(c)
#<class 'str'>
#hello

type及isinstance

#type()判断数据类型
#isinstance()判断数据类型是否相同
str1 = [1,2]
print(type(str1))
print(isinstance(str1,list))
#<class 'list'>
#True