Self-developed artificial intelligence ------ variable understanding and operations in Python,

Self-developed artificial intelligence ------ variable understanding and operations in Python,

Today, I will introduce the Number variable in python, which is somewhat different from c ++ and java. Let's introduce it to you as follows:

In python, you do not need to declare the variable type, but you need to assign a value to the variable before using it. It is meaningless to have no variable worth it, and the compiler will not pass

I. Integer ----- int:

The usage of int in python is roughly the same as that in c ++:

A = 12

Print

The printed result is: 12.

Here I will first introduce several functions

Type (): return the Data type in parentheses.

A = 'hello'

Print type ()

>>>> <Type 'string'>

 

Len (): returns the length of the variable in parentheses.

Note: The len () method cannot be of the int type.

A = 'Hello world'

Print len ()

>>> 11

Ii. Floating Point ------ float

Float is composed of integer and decimal parts. It can also be expressed by scientific notation.

A = 1.23

Print type ()

>>< Type 'float'>

 

Iii. Plural

The plural part is composed of the real number and the virtual number. a + bj or comple (a, B) can be used. The real part a and the virtual Part B of the plural are float.

 

Iv. Data Type Conversion

Int (x): converts x to an integer.

Float (x): converts x to a floating point number.

Complex (x): converts x to a plural number. The real part is x, and the virtual part is 0.

A = 1.23

Print complex ()

>>> (1.23 + 0j)

Complex (x, y): converts x and y into a plural number. The real number is x, and x and y are numeric expressions.

 

5. Constants

Python has two common constants, PI and E.

PI: mathematical constant pi (circumference rate)

E: mathematical constant e. It is a natural number.

 

Now, today's introduction is over, hoping to help you.