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| Both sides previous revision Previous revision Next revision | Previous revision | ||
| python [2020/01/03 15:08] admin | python [2021/05/06 11:15] (current) admin | ||
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| - | ### Create a list of objects from a class | + | ## Data Type | 
| + | |||
| + | ^ Example  ^ Data Type ^ | ||
| + | | x = "Hello World"  | str | | ||
| + | | x = 20 | int | | ||
| + | | x = 20.5 | float | | ||
| + | | x = 1j | complex  | | ||
| + | | x = ["apple", "banana", "cherry"]  | list | | ||
| + | | x = ("apple", "banana", "cherry")  | tuple | | ||
| + | | x = range(6)  | range | | ||
| + | | x = {"name" : "John", "age" : 36} | dict | | ||
| + | | x = {"apple", "banana", "cherry"}  | set | | ||
| + | | x = frozenset({"apple", "banana", "cherry"})  | frozenset  | | ||
| + | | x = True | bool | | ||
| + | | x = b"Hello"  | bytes | | ||
| + | | x = bytearray(5)  | bytearray  | | ||
| + | | x = memoryview(bytes(5))  | | | ||
| + | |||
| + | ref: https://medium.com/@shawnren527/learn-about-python-3-data-types-numbers-and-strings-76c75a917c9b | ||
| + | |||
| + | ### Class | ||
| + | ref:https://www.w3schools.com/python/python_classes.asp | ||
| + | |||
| + | ## Create a list of objects from a class | ||
| ```python | ```python | ||
| - | swatchList = [] | + | swatchList = [] | 
| - | swatchList.append(Swatch("Sky1",22,40,76)) | + | swatchList.append(Swatch("Sky1",22,40,76)) | 
| - | # Swatch is the name of the class | + | # Swatch is the name of the class | 
| ``` | ``` | ||
| <wrap lo> | <wrap lo> | ||
| Line 10: | Line 33: | ||
| </wrap> | </wrap> | ||
| - | ### Format Variables | + | ## Format Variables | 
| ```python | ```python | ||
| print('%s %.2f' % ("hue =",swSky1.hue)) | print('%s %.2f' % ("hue =",swSky1.hue)) | ||
| print('{0} {1:.2f}'.format("hue =",swSky1.hue)) | print('{0} {1:.2f}'.format("hue =",swSky1.hue)) | ||
| print("hue =", format(swSky1.hue,'.2f')) | print("hue =", format(swSky1.hue,'.2f')) | ||
| + | # f:float, x:hex, s:string | ||
| ``` | ``` | ||
| The three lines above give the same result ````hue = 220.00````.\\ | The three lines above give the same result ````hue = 220.00````.\\ | ||
| Line 25: | Line 49: | ||
| - | ### Plot (matplotlib) | + | ## Plot (matplotlib) | 
| py37-matplotlib has the following notes:\\ | py37-matplotlib has the following notes:\\ | ||
| The default backend is the interactive Mac OS X backend. Different backends can be specified using the | The default backend is the interactive Mac OS X backend. Different backends can be specified using the | ||
| Line 31: | Line 55: | ||
| https://matplotlib.org/tutorials/introductory/usage.html#backends | https://matplotlib.org/tutorials/introductory/usage.html#backends | ||
| + | ```python | ||
| + | import matplotlib.pyplot as plt | ||
| + | plt.plot(x, y, color='black', linestyle = 'none', marker='o', markerfacecolor=(swatch.r/255.0,swatch.g/255.0,swatch.b/255.0), markersize=12) | ||
| + | ``` | ||
| + | |||
| + | Note: ```markerfacecolor``` accept RGB, HEX and simple color text description: ```markerfacecolor=(r,g,b)```, ```markerfacecolor='#333399'```, ``` markerfacecolor='green'``` | ||
| + | |||
| + | ### 3D plot: | ||
| + | https://jakevdp.github.io/PythonDataScienceHandbook/04.12-three-dimensional-plotting.html | ||
| - | ### Common Error | + | ## Common Error | 
| ```python | ```python | ||
| File "main.py", line 15 | File "main.py", line 15 | ||