"Python Data Analysis" NumPy module

NumPy modules can efficiently process data, provide array support, and many modules rely on him, such as: Pandas, SciPy, matplotlib

Installing NumPy

First to the website: https://www.lfd.uci.edu/~gohlke/pythonlibs/Find NUMPY+MKL

My Python version is 3.6.1, the system is 64-bit

So the package that corresponds to the download is:

After downloading the package, go to the directory where the package is located (for example: D:\ installation package \ installation package ~PYTHON\NUMPY-1.13.3+MKL-CP36-CP36M-WIN_AMD64.WHL).

Use the following command to install

Pip Install NUMPY-1.13.3+MKL-CP36-CP36M-WIN_AMD64.WHL

The first installation error is as follows:

The above error occurs because the environment variable is not configured

Solution:

Add a path to an environment variable

After the add is complete, re-execute

Pip Install NUMPY-1.13.3+MKL-CP36-CP36M-WIN_AMD64.WHL

After the installation is successful, then we can use NumPy.

NumPy Tutorials

(1) NumPy create a one-dimensional array

Syntax: Numpy.array ([element 1, Element 2,..., element n])

Import numpyx = Numpy.array (["1","2","5  ","one"])print(x)

Run Result: [' 1 ' 2 ' 5 ' 11 ']

(2) NumPy create a two-dimensional array

Syntax: Numpy.array ([[Element 1, Element 2,..., element n],[element 1, Element 2,..., element n],..., [element 1, Element 2,..., element N]])

Import= Numpy.array ([[11,4,2],[2,6,1],[32,6,42]])print(y)

Operation Result:

[[11 4 2]
[2 6 1]
[32 6 42]]

(3) Sort by using sort

ImportNumPy#Numpy.array ([element 1, Element 2,..., element n])x = Numpy.array (["m","2","5"," One"])#sort xX.sort ()Print(x)#Numpy.array ([[Element 1, Element 2,..., element n],[element 1, Element 2,..., element n],..., [element 1, Element 2,..., element N]])y = Numpy.array ([[11,4,2],[2,6,1],[32,6,42]])#Sort yY.sort ()Print(y)

Post-order results:

[' One ' 2 ' 5 ' m ']
[[2 4 11]
[1 2 6]
[6 32 42]]

Description: The following actions are based on the sorted array

(4) Get the values in the array

For example, get the 6 value of the array y

# gets the 6 value of the array y y1 = y[1][2]print(y1)

(5) Get maximum and minimum values

# gets the maximum value in Y and the minimum value y2 = y.max ()print(y2)# operation result is: 1=  Y.min ()print(y3)# operation result is:

(6) Slicing

Gets the value in the array according to the defined subscript value

Syntax: array [start subscript: End subscript +1]

 #   slice  x1 = X[1:3] #   print   (x1)  #   run result: [' 2 ' 5 ']  x2  = x[:2] #   Take the element from the beginning to the subscript 1  print   (x2)  #   run result: [' one ' 2 ']   x3  = x[1:] #   The element labeled 1 from the bottom has been taken to the last  print   (x3)  #   run result: [' 2 ' 5 ' m ']  

Python Data Analysis NumPy module