Today I'm going to introduce you to the Number variable in python, which is a bit different from c++ and java, so let's introduce it to you.
You don't have to declare the type of a variable in python, but you do have to assign a value to it before you can use it; without a value it's meaningless, and the compiler won't pass it.
I : Integer -----int.
The usage of int in python is more or less the same as in c++: the
a=12
print a
The printout is :12
I'd like to start by introducing you to a couple of functions
type(): returns the type of the data in parentheses.
a='hello' print type(a) >>>><type 'string'>
len(): Returns the length of the variable in parentheses.
Note: You can't use int with the len() method.
a='hello world' print len(a) >> >11
II : Floating point type ------float
Floating point consists of an integer part and a decimal part, which can also be expressed in scientific notation.
a=1.23 print type(a) >> <type 'float'>
III: Plural
Complex numbers are made up of a real part and an imaginary part,you can use a+bj or complex(a,b),the real part a and the imaginary part b of a complex number are floating point type
IV: Data type conversion
int(x) : convert x to an integer
float(x) : converts x to a floating point number
complex(x) : convert x to a complex number with real part x and imaginary part 0
a=1.23
print complex(a)
>>>(1.23+0j)
complex(x,y) : converts x and y to a complex number with the real part being x and x and y being numeric expressions
V: Constants
Two of the more common constants in python are PI and E
PI: the mathematical constant pi (pi).
E: mathematical constant e. i.e. natural number
summarize
The above is a small introduction to the Python language to recognize and operate the variables, I hope to help you, if you have any questions please leave me a message, I will reply to you in time. Here also thank you very much for your support of my website!