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This article mainly explains "how to use the basic module of Python". The content of the explanation is simple and clear, and it is easy to learn and understand. Please follow the editor's train of thought to study and learn "how to use the basic module of Python".

1. Import of module

There are three ways:

First: import module name

The second type: import module name as new name

The third type: from module name import function name

Import math # the first way

Import numpy as np # the second way

Import matplotlib as mpl # the second way

# import matplotlib.pyplot as plt

From matplotlib import pyplot as plt # the third way

# import seaborn

Def calc_e_small (x):

N = 10

F = np.arange (1, n = 1) .cumprod ()

B = np.array ([x] * n) .cumprod ()

Return np.sum (b / f) + 1

Def calc_e (x):

Reverse = False

If x < 0: # handles negative numbers

X =-x

Reverse = True

Ln2 = 0.69314718055994530941723212145818

C = x / ln2

A = int (cis 0.5)

B = x-a*ln2

Y = (2 * * a) * calc_e_small (b)

If reverse:

Return 1/y

Return y

If _ name__ = = "_ _ main__":

T1 = np.linspace (- 2,0,10, endpoint=False)

T2 = np.linspace (0,4,20)

T = np.concatenate ((T1, T2))

Print (t) # horizontal axis data

Y = np.empty_like (t)

For I, x in enumerate (t):

Y [I] = calc_e (x)

Print ('e ^', x,'=', y [I],'(approximate)\ tasking, math.exp (x),'(true value)')

Plt.figure (facecolor='w')

Mpl.rcParams ['font.sans-serif'] = [' SimHei']

Mpl.rcParams ['axes.unicode_minus'] = False

Plt.plot (t, y, 'rMurray, t, y, 'go', linewidth=2, markeredgecolor='k')

Plt.title (Application of Taylor expansion-exponential function, fontsize=18)

Plt.xlabel ('Xerox, fontsize=15) how much is the http://www.zykdyjyy.com/ of Zhengzhou expelling birthmark Hospital

Plt.ylabel ('exp (X)', fontsize=15)

Plt.grid (True, ls=':')

Plt.show ()

2.if name = = "main" statement

Python is a scripting language. Unlike compiled languages, programs are compiled into binary and then run, but are dynamically interpreted line by line. That is, to run from the first line of the script, there is no unified entry.

When there is this sentence in a Python file, it is like the main function main in C language, where the program starts. This statement prevents some statements in the imported file under the current file from being executed by the line-by-line mechanism of Python.

Because if a .py file (module) is run directly, its _ _ name__ value is _ _ main__, that is, the module name is _ _ main__.

So, if name = 'main' means that when the .py file is run directly, the code block under if name =' main' will be run; when the .py file is imported as a module, the code block under if name = 'main' will not be run.

Thank you for reading, the above is the content of "how to use the Python basic module". After the study of this article, I believe you have a deeper understanding of how to use the Python basic module, and the specific use needs to be verified in practice. Here is, the editor will push for you more related knowledge points of the article, welcome to follow!

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