# How IOS developers learn python programming 3-operator 2

2022-01-31 04:41:32

This is my participation 11 Yue Gengwen challenges 3 God , Check out the activity details ：2021 The last time Gengwen challenge .

### member operator

`in` And `not in` yes `Python` Unique operators （ It's all lowercase ）. Used to determine whether an object belongs to a collection , Very fast . Back to `True` perhaps `False`.

1. Judge `a` Whether in `list1` In the list ：
``````list1 = [1, 2, 3, 4, 5]
a = 1

for i in list1:
if i == a:
print("a stay list1 in ")
else:
print('a be not in list1 in ')

flag = False
for i in list1:
if i == a:
flag = True
break
if flag:
print("a yes list1 One of the elements of ")
else:
print("a No list1 The elements of ")

#  If you use in Operator , There's no need for such trouble
list1 = [1, 2, 3, 4, 5]
a = 1
if a in list1:
print("a yes list1 One of the elements of ")
else:
print("a No list1 The elements of ")list1 = [1, 2, 3, 4, 5]
a = 1

for i in list1:
if i == a:
print("a stay list1 in ")
else:
print('a be not in list1 in ')

flag = False
for i in list1:
if i == a:
flag = True
break
if flag:
print("a yes list1 One of the elements of ")
else:
print("a No list1 The elements of ")

#  If you use in Operator , There's no need for such trouble
list1 = [1, 2, 3, 4, 5]
a = 1
if a in list1:
print("a yes list1 One of the elements of ")
else:
print("a No list1 The elements of ")list1 = [1, 2, 3, 4, 5]
a = 1

for i in list1:
if i == a:
print("a stay list1 in ")
else:
print('a be not in list1 in ')

flag = False
for i in list1:
if i == a:
flag = True
break
if flag:
print("a yes list1 One of the elements of ")
else:
print("a No list1 The elements of ")

#  If you use in Operator , There's no need for such trouble
list1 = [1, 2, 3, 4, 5]
a = 1
if a in list1:
print("a yes list1 One of the elements of ")
else:
print("a No list1 The elements of ")
Copy code ``````

### Identity operator

`Python` Characteristic grammar （ It's all lowercase ）：

• `is` Used to judge whether the reference of two variables is the same object （ You can use `id()` Get objects ）.
• `is not` opposite .

️ Be careful ： `is` And comparison operators `==` The difference between ：

• `==` Used to determine whether the values of objects referenced by variables are equal .
``````>>> a = [1,2,3]
>>> b = [1,2,3]
>>> a is b
False
>>> a == b
True

>>> a = 2
>>> b = 2.0 #  It can be done by id() Check the memory address
>>> a is b
False
>>> a == b
True
Copy code ``````

### Ternary operator

`python` The representation of the trinary operator in ：

``````True_statements if expression else False_statements
Copy code ``````

for example ：

``````a = 1
b = 2
if a+b>3:
print(a+b)
else:
print(b-a)

a+b if a+b>3 else b-a   #  Ternary operator
Copy code ``````

### Operator priority

The following table lists all operators from the highest to the lowest priority . Operators with higher priority have priority in calculation or processing , The same level is calculated from left to right （ Except for assignment operators , It's in right to left order ）：

Operator describe
** Index （ The highest priority ）
~ + - Flip by bit , One yuan plus sign and minus sign （ The last two methods are called [email protected] and [email protected]
* / % // ride 、 except 、 modulus 、 Divide and conquer
+ - Add 、 Subtraction
>> << Move right 、 Move left
& position AND
^
<= < > >= Comparison operator
<> == != Equals operator
= %= /= //= -= += *= **= Assignment operator
is is not Identity operator
in not in member operator
not or and Logical operators

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