Those of you who are familiar with programming languages probably know that there is an auto-increment ( ++ ) and auto-decrement ( — ) operator in arithmetic operators, it is very common when you’re writing loops. But the ++ and — operator might behave differently in Python operators, and it needs to be noticed.
Take a look at the Python code below.
>>> num = 1 >>> ++num 1 # Python doesn't know the ++ operator >>> num 1
Similarly, Python does not recognize self decrement operators –.
>>> num = 1 >>> --num 1 >>> num 1
Attention! If you need a self increasing operation, you can only honestly use the variable assignment method such as num = num + 1.
Let’s look at below python example code.
>>> x = 1 >>> >>> y = 1 >>> >>> id(x) 4427814032 >>> >>> id(y) 4427814032 >>> >>> x is y True
As you can see, in Python, variables are based on content rather than on variable names. So if a variable’s content is 5, no matter what name you give to the variable, the ID of this variable is the same, which also means that a variable in Python can be accessed by multiple names.