The difference between division in python2 and 3

Division in python2 means that an integer (a number without a decimal part) is divided by another integer, and the decimal part of the calculation result is truncated, leaving only the integer part. Sometimes, this function is more useful. For example, when doing something that needs to take a number of digits, you can use this feature to end a loop, etc., but usually, you don't need this.

>>>1/2
0

So, there are two solutions:

1) Use real numbers (numbers including decimal points) instead of integers Operation

Real numbers are called floating-point numbers (Float, or Float-point number) in Python. As long as one of the numbers participating in the operation is a floating-point number, it is a floating-point number operation, and the result of the operation is also a floating-point number. , the decimal part will not be truncated.

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such as

>>>1.0/2.0
0.5
>>>1/2.0
0.5
>>>1.2/2
0.5
>>>1/2.
0.5

2) Let Python change the default execution method of division

You can add the following statement to the program, or execute it in the interpreter:

>>>from_future_import division

There is another method. If you run Python through the command line (such as on a Linux system), you can use the command switch - Qnew

uses the above two methods. You can just perform ordinary division operations.

>>>1/2
0.5

At this time, the single slash is no longer used as a divisor, but Python provides another operator for implementing integer division-double slash:

>>>1//2
0

Even if it is a floating point number , double slashes will also perform integer division

>>>1.0/2.0
0

In versions after Pytho3.0

becomes true division in Python3.0 (decimals will be maintained regardless of type parts, even integer divisions are represented as floating point numbers).

>>> 3/2
1.5
>>> 3/2.0
1.5
>>> 4/2
2.0
>>> 4/2.0
2.0

Note:

Everyone must pay attention to the division in python3. The result is a decimal. This needs to be noted.

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