【九月打卡】第5天Python第五章变量与运算符

课程名称：全面系统Python3.8入门+进阶（程序员必备第二语言）

课程章节：  5-10 成员运算符   5-11 身份运算符

主讲老师：7七月

课程内容：

今天学习的内容包括：

成员运算符

身份运算符

课程收获：

5-10 成员运算符

在  ，不在

a = 1

a 是否在[1,2,3,4,5]

a in [1,2,3,4,5]  -----True

b = 6

b in [1,2,3,4,5]  ----False

b not in [1,2,3,4,5]  -----True

b = 'h'

b in 'hello' ---- True

b not in (1,2,3,4,5)----True

b not in {1,2,3,4,5} ----True

字典的成员运算符

b = 'a'

b in {'c':1}-----False

b = 1

b in {'c':1} ------False

b = 'c'

b in  {'c':1} ----- True

#规律：说明，字典的成员运算时肯定key：value 键值对立面的键来判断的。他判断的是key。

5-11 身份运算符

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1","marks":[{"type":"color","value":"#403ED6"}]}]}],"state":{}},{"type":"block","id":"GPz0-1661762634787","name":"paragraph","data":{"version":1},"nodes":[{"type":"text","id":"Md4i-1661762634786","leaves":[{"text":"b =1","marks":[{"type":"color","value":"#403ED6"}]}]}],"state":{}},{"type":"block","id":"wi9j-1661762637846","name":"paragraph","data":{"version":1},"nodes":[{"type":"text","id":"fVnz-1661762637844","leaves":[{"text":"a is b ------True","marks":[{"type":"color","value":"#403ED6"}]}]}],"state":{}},{"type":"block","id":"1wAC-1661762645016","name":"paragraph","data":{"version":1},"nodes":[{"type":"text","id":"m3gJ-1661762645014","leaves":[{"text":"a = " hello'","marks":[{"type":"color","value":"#403ed6"}]}]}],"state":{}},{"type":"block","id":"ebpa-1661762652105","name":"paragraph","data":{"version":1},"nodes":[{"type":"text","id":"40jn-1661762652104","leaves":[{"text":"b="world" ","marks":[]}]}],"state":{}},{"type":"block","id":"twsm-1661762657652","name":"paragraph","data":{"version":1},"nodes":[{"type":"text","id":"mr4j-1661762657650","leaves":[{"text":"a="" is="" b="" -----false","marks":[]}]}],"state":{}},{"type":"block","id":"igjt-1661762664718","name":"paragraph","data":{"version":1},"nodes":[{"type":"text","id":"b2cf-1661762664716","leaves":[{"text":"c="hello" ","marks":[{"type":"color","value":"#403ed6"}]}]}],"state":{}},{"type":"block","id":"ogts-1661762672920","name":"paragraph","data":{"version":1},"nodes":[{"type":"text","id":"0vrv-1661762672919","leaves":[{"text":"a="" c="" ------true","marks":[{"type":"color","value":"#403ed6"}]}]}],"state":{}},{"type":"block","id":"irzi-1661762528428","name":"paragraph","data":{"version":1},"nodes":[{"type":"text","id":"bapv-1661762528427","leaves":[{"text":"2个变量他们的取值相等的时候，身份运算符才会返回true。","marks":[]}]}],"state":{}},{"type":"block","id":"gzup-1661762681577","name":"paragraph","data":{"version":1},"nodes":[{"type":"text","id":"ayum-1661762681576","leaves":[{"text":"is="" 和关系运算符="=有什么区别。","marks":[]}]}],"state":{}},{"type":"block","id":"l0qk-1661762759425","name":"paragraph","data":{"version":1},"nodes":[{"type":"text","id":"g2RN-1661762759423","leaves":[{"text":"a" =="" 1","marks":[{"type":"color","value":"#403ed6"}]}]}],"state":{}},{"type":"block","id":"plca-1661762759763","name":"paragraph","data":{"version":1},"nodes":[{"type":"text","id":"2oj2-1661762759764","leaves":[{"text":"b="1","marks":[{"type":"color","value":"#403ED6"}]}]}],"state":{}},{"type":"block","id":"6ZHJ-1661762759765","name":"paragraph","data":{"version":1},"nodes":[{"type":"text","id":"Octq-1661762759766","leaves":[{"text":"a" ------true","marks":[{"type":"color","value":"#403ed6"}]}]}],"state":{}},{"type":"block","id":"b1el-1661762761507","name":"paragraph","data":{"version":1},"nodes":[{"type":"text","id":"wxmb-1661762761506","leaves":[{"text":"a="=" -----true","marks":[{"type":"color","value":"#403ed6"}]}]}],"state":{}},{"type":"block","id":"vkgb-1661762768214","name":"paragraph","data":{"version":1},"nodes":[{"type":"text","id":"tjtf-1661762768212","leaves":[{"text":"a="1","marks":[{"type":"color","value":"#FF0001"}]}]}],"state":{}},{"type":"block","id":"BCL2-1661762771959","name":"paragraph","data":{"version":1},"nodes":[{"type":"text","id":"gnAQ-1661762771958","leaves":[{"text":"b" 1.0","marks":[{"type":"color","value":"#ff0001"}]}]}],"state":{}},{"type":"block","id":"mmce-1661762781309","name":"paragraph","data":{"version":1},"nodes":[{"type":"text","id":"bdxx-1661762781307","leaves":[{"text":"a="=" ----true","marks":[{"type":"color","value":"#ff0001"}]}]}],"state":{}},{"type":"block","id":"1mof-1661762794802","name":"paragraph","data":{"version":1},"nodes":[{"type":"text","id":"kzjc-1661762794800","leaves":[{"text":"a="" ----false","marks":[{"type":"color","value":"#ff0001"}]}]}],"state":{}},{"type":"block","id":"wdkj-1661762799621","name":"paragraph","data":{"version":1},"nodes":[{"type":"text","id":"1qe4-1661762799620","leaves":[{"text":"is和="=" 还是有区别的，关系运算符他所比较的是2个变量的值是否相等；is他不是比较值相等，他比较是2个变量身份是否相等。内存地址是否相等。","marks":[{"type":"color","value":"#ff0001"}]}]}],"state":{}},{"type":"block","id":"cqk8-1661762891490","name":"paragraph","data":{"version":1},"nodes":[{"type":"text","id":"uumg-1661762891489","leaves":[{"text":"id(a)="" -----1825007744","marks":[{"type":"color","value":"#ff0001"}]}]}],"state":{}},{"type":"block","id":"qoc9-1661762904414","name":"paragraph","data":{"version":1},"nodes":[{"type":"text","id":"su5p-1661762904412","leaves":[{"text":"id(b)="" ----68997248","marks":[{"type":"color","value":"#ff0001"}]}]}],"state":{}},{"type":"block","id":"fn0p-1661762919544","name":"paragraph","data":{"version":1},"nodes":[{"type":"text","id":"bzue-1661762919543","leaves":[{"text":"is="" 一个变量的身份是否和另一个变量相等，not="" 一个变量的身份是否和另一个变相不等。","marks":[{"type":"color","value":"#6ddeff"}]}]}],"state":{}},{"type":"block","id":"yzet-1661763114403","name":"paragraph","data":{"version":1},"nodes":[{"type":"text","id":"1ara-1661763114402","leaves":[{"text":"集合是无序的{}，元组属于序列他是有序的。所以="=ab为True，cd为False","marks":[{"type":"color","value":"#6DDEFF"}]}]}],"state":{}}]'">

最终返回结果同样是布尔值。

a = 1

b =2

a is b ----- False

a = 1

b =1

a is b ------True

a = 'hello'

b = 'world'

a is b -----False

c = 'hello'

a is c  ------True

2个变量他们的取值相等的时候，身份运算符才会返回True。

is 和关系运算符==有什么区别。

a = 1

b =1

a is b ------True

a == b -----True

a = 1

b = 1.0

a == b ----True

a is b ----False

is和== 还是有区别的，关系运算符他所比较的是2个变量的值是否相等；is他不是比较值相等，他比较是2个变量身份是否相等。内存地址是否相等。

id(a) -----1825007744

id(b) ----68997248

is  一个变量的身份是否和另一个变量相等，not is 一个变量的身份是否和另一个变相不等。

集合是无序的{}，元组属于序列他是有序的。所以==ab为True，cd为False