004.Python运算符

var1 = 10
var2 = 7
res = var1 + var2
print(res)

var1 = 10
var2 = 7
res = var1 - var2
print(res)

var1 = 10
var2 = 7
res = var1 * var2
print(res)

var1 = 10
var2 = 7
res = var1 / var2
print(res)

res = 14 / 7
print(res)

res = 14 // 7
print(res)
# 如果被除数 或者 除数是一个小数,那么结果后面加一个.0
res = 14.3 // 7
print(res)

res = 8 % 3  # 正常取余数
print(res)
res = -8 % 3 #-2 + 3 = 1
print(res)
res = 8 % -3 #2 + (-3) = -1
print(res)
res = -8 % -5 #-3果两者符号都是符号 那么直接取余数跟上一个负号
print(res)

res = 3 ** 2
print(res)
res = 2 ** 4
print(res)

 > < >= <= == != 

# >
var1 = 5
var2 = 3
res = var1 > var2
print(res)

# <
res = var1 < var2
print(res)

# >=
res = var1 >= var2
print(res)
res = 5>=5   #满足一个条件即可 方返回真
print(res)

# <=
res = var1 <= var2
print(res)
res = 5<=5  #满足一个条件即可 方返回真
print(res)

# ==
res = var1 == var2
print(res)

# !=
res = var1 != var2
print(res)

= += -= *= /= //= %= **=

var1 = 8
var2 = 3
# =
var1 = var2
print(var1)

# +=
var1 += var2
‘‘‘var1 = var1 + var2‘‘‘
print(var1)

# -=
var1 -= var2
‘‘‘var1 = var1 - var2‘‘‘
print(var1)

# *=
var1 *= var2
var1 = var1 *var2
print(var1)

# /=
var1 /= var2
‘‘‘var1 = var1 / var2‘‘‘
print(var1)

# //= 地板除运算
var1 //= var2
var1 = var1 // var2
print(var1)

# %= 余运算
var1 %= var2
var1 = var1 % var2
print(var1)

# **= 幂运算
var1 = 4
var1 **= 3
print(var1)

strvar = "吾尝终日而思已，不如须臾之所学也"
res = "吾" in strvar
print(res)
res = "终日"  in strvar
print(res)
res = "不如" in strvar
print(res)

# list tuple set
listvar = ["老子","孔子","孟子","荀子"]
res = "孙子" not in listvar
print(res)
setvar = {"庄子","子路","冉有","颜回"}
print(setvar)
res = "颜回" in setvar
print(res)
tuplevar = ("子渊","冉求","公孙龙")
res = "冉求" not in tuplevar
print(res)

# dict  成员运算符 判断字典时 判断的是键 不是那个所对应的值
dictvar = {"top":"程咬金","bottom":"甄姬","middle":"嫦娥"}
res = "程咬金" in dictvar
print(res)
res = "top" not in dictvar
print(res)

仅仅限定在3.6版本之前 是变量的缓存 ,
判断一个值在某个范围内存在,就不会再另外创建一个相同的值,为了节省内存空间
3.7之后不再划定范围,只要有一份就缓存
提出小数据池 或者变量缓存是为了提升代码执行的效率,减少内存占用空间

# 整型 -5 ~ 正无穷
var1 = 19
var2 = 19
res = var1 is var2
print(res)

# 浮点型  非负数
var1 = -5.52
var2 = -5.52
res = var1 is not var2
print(res)

# 复数 在实数 + 虚数这样的结构中永远不一样 但如果只有虚数 在值相同情况下一样
var1 = 3+4j
var2 = 3+4j
res = var1 is  var2
print(res)
var1 = 6j
var2 = 6j
res = var1 is not var2
print(res)

# bool 在布尔值相同的情况下 id一样
var1 = True
var2 = True
res = var1 is var2
print(res)

# 容器类型数据地址判断

# str 字符串而言，字符串值相同情况下，id一致
var1 = "你"
var2 = "你"
print(var1 is var2)


var1 = (1,23)
var2 = (1,23)
print(var1 is var2)
# 空元组例外
var1 = ()
var2 = ()
print(var1 is var2)

# 剩下的容器类型数据无论什么值都不一样
var1 = [1,2]
var2 = [1,2]
print(var1 is not var2)

and or not 

# and 逻辑与
res  = True and  True
print(res)
res = True and False
print(res)
res = False and True
print(res)
res = False and False
print(res)

# or  逻辑或
res = True or True
print(res)
res = True or False
print(res)
res = False or True
print(res)
res = False or False
print(res)

# not 逻辑非(相当于取反)
res = not True
print(res)
res = not False
print(res)

‘‘‘
一个or或者一个and 情况下
(1)True or something
(2)False and something
‘‘‘

print("<===>")
False or print(123)
True and print(456)

# 逻辑优先级
# () > not > and > or 
res = 5 or 6 and 7
print(res)
res = (5 or 6) and 7 # 5 and 7
print(res)
res = not (5 or 6) and 7 # not 5 and 7 => False and 7 => False
print(res) # 5 or 7

res = 1<2 and 3>4 or 5<6 # True and False or True => False or True
print(res)
res = 1<2 and 3>4 or 5>6 and 7<8 or 9>10 # True and False or False and True or False =>False or False or False => False or False => False        
print(res)

# 这种情况特殊,上来直接短路,后面的不用再按照and or 优先级算了 (例外)
res = 5 or 6 and 7 or 8 and 9 or 10
print(res)
# 如果上来直接是假,不一定结果也是假,要依次向后计算
# False and True or True 


#数据类型判断 isinstance
‘‘‘
int float bool complex str list tuple set dict

isinstance(要判断类型的数据,(类型1,类型2,类型3......))
如果在类型元组当中,返回真
如果不在类型元组当中,返回假
‘‘‘
intvar  = 15
print(isinstance(intvar,int))
strvar = "789"
print(isinstance(strvar,(int,str,list)))

& | ~ ^ << >>

var1 = 19
var2 = 15
# & 按位与
res = var1 & var2
print(res)

10011
01111
00011

var1 = 19
var2 = 15
# & 按位或
res = var1 | var2
print(res)

10011
01111
11111

""" n<<m  n乘以2的m次幂  """
res = 5 << 2  # 相当于5 * 2的2次幂
print (res)

00000101
00010100
4+16 = 20

res = 5 >> 1
"""
00000101
00000010
"""
print(res)

var1 = 19
var2 = 15
res = var1 ^ var2
‘‘‘
10011
01111
11100
‘‘‘
print(res)

res = ~19
res = ~-21
print(res)

res = 5+5 << 6 // 3 is 40 and True    #规范写法   res = (5+5) << (6 // 3) is 40 and True  
print (res)