- numpy：数值计算库
- scipy：统计分析库
- python版本：python 2.x与python 3.x之间没有向后兼容性，python 3.x编写的代码不能被python 2.x执行
(base) zsx@LAPTOP-BJTHAGI7:~$ python --version
Python 3.7.3
(base) zsx@LAPTOP-BJTHAGI7:~$ python
Python 3.7.3 (default, Mar 27 2019, 22:11:17)
[GCC 7.3.0] :: Anaconda, Inc. on linux
Type "help", "copyright", "credits" or "license" for more information.
>>>
- 数据类型：使用
type(data)
>>> type(12)
<class 'int'>
>>> type(1.2)
<class 'float'>
>>> type('str')
<class 'str'>
>>> type([1,2,3])
<class 'list'>
>>> type((1,2,3))
<class 'tuple'>
>>> type({1,2,3})
<class 'set'>
>>> type({'1':1,'2':2,'3':3})
<class 'dict'>
- python是
动态类型语言的编程语言，动态是指变量的类型是根据情况自动决定的，python根据变量赋值的类型判断变量的数据类型
-
list与dict的关系：list根据索引，按照0,1, 2, ...的顺序存储值，而dict根据键值对的形式存储值
- class
class MyClass:
def __init__(self, param1, ...): # constructor
self.param1=param1
...
def fun_1(self, param1, ...): # method 1
...
def fun_2(self, param1, ...): # method 2
...
- matplotlib的两个examples
import numpy as np
import matplotlib.pyplot as plt
x = np.arange(0,6,0.1)
y1 = np.sine(x)
y2 = np.cos(x)
plt.plot(x, y1, label="sin")
plt.plot(x, y2, linestyple="--", label="cos")
plt.xlabel("x")
plt.ylabel("y")
plt.title("sin & cos")
plt.legend()
plt.show()
import matplotlib.pyplot as plt
from matplotlib.image import imread
img=imread("lena.png") # read image file
plt.imshow(img) # show image
plt.show()
