Python can perform simple calculator functions: such as >>2+2 ==> 4,1/2==>0.5 or write 1/2.0==>0.5 (take float) 1//2 ==>0 ("//" will force rounding) -3**4 ==>- 81 (Power function operation level is higher than the first operation, similar to ==>-(3**4)), if you want to achieve the result is positive write: (-3) **4 can also be written as function pow (3,4) abs ( -1) ==>1 (ABS rounding) round (0.6) ==> 1 (Round rounding) Reference module: Import math (preferably with this) and then call Math.floor (12.7) ==>12 (rounding down) from math import sqrt (so that the reference module is not prefixed) for example: sqrt ( ==>4.0 of course, you can also use variables to kill methods such as: PF = MATH.SQRTPF (4) ==>2.0math.sqrt () can only handle floating point numbers, the remaining imaginary numbers (and the sum of the real and imaginary numbers) with cmath.sqrt (-16) = =>4jpython can handle large integers but need to add l to the end of the CountFor example: 1000000000000000000000000L variable names can be in letters, underscores (_) numbersbut you can't start with numbers .int (x [, Base]) converts x to an integer long (x [, Base]) converts x to a long integer, float (x) converts x to a floating-point number complex (R EAL [, Imag]) creates a complex number str (x) to convert an object x to a string repr (x) to convert an object x to an expression string eval (str) Used to calculate a valid in stringPythonExpression and returns an object tuple (s) to convert the sequence s to a tuple list (s) to convert the sequence s into a listing Chr (x) will be a Converts an integer to a character unichr (x) converts an integer to a Unicode character, Ord (x) converts a character to its integer value, Hex (x) Converts an integer to a hexadecimal string Oct (x) converts an integer to an octal stringThere are two types of running code:1, >>> return immediately execute 2, plain text code and can be divided into two modes 1) Open the CMD input. The absolute path of PY 2) directly inside the IDE CTRL+F5The first python runs the program code as follows:Name = input ("What is your name?") #为变量name赋值print ("Hello" +name+ "!") #打印input ("press<enter>") #避免窗口闪退转义符 ("\") Example: "\" hello!\ "she said" ==> ' "hello!" she said ' "\ n" is a newline character, but sometimes I don't want him to escape in use for example: print ("C:\nwhere") ==>c:where now if we want ' C : \nwhere ' has two methods to implement 1, use ' \ ' escape characters such as print ("C:\\nwhere") ==>c:\nwhere2, take advantage of original characters such as: print (r "C:\nwhere") ==>c:\ Nwhere #原始字符最后一个字符不能为 ' \ ', otherwise python will not be able to recognize whether the string should end if you need to add ' \ ' after the original field to write print (r "C:\nwhere" "\") ==>c:\nwhere\ Continue learning data Structures tomorrow
First, the Python Expression Foundation
