Use Python to detect your computer system and name
I work on several computers, sometimes Widows, sometimes Linux, so I got a problem after I pull my project file from Git. That is the file path. To cope with this problem, I have to find out which computer I…
Read an Image with python
If you want to read an image, you will need the ‘image’ package: import Image read the image: Image.open(filename) convert the Image to grey scale: Image.open(filename).convert(‘L’) convert the image to array: numpy.asarray(Image.open(filename).convert(‘L’)) Notice: Here is a introduction to “Image” package…
Use the np.array.argsort() and list.sort() to get the rank of the number
I have a list and I want to get the rank for each member. This is important for many data mining algorithm, for example kNN (k-Nearest-Neighbor), you want to know the rank of a certain record. For example: myList =…
sort 2d array in python
There are many ways to sort a 2d arrays. In general, you can use the sorted(), np.array.sort(),… But you should also understand what is meaning of list1.sort(list2) ravel() vs. flatten() what return the key function back in sorted() what will…
the crazy * in zip()
I just want to reshape the List without use the numpy, so I found a piece of crazy code in stackoverflow: output: [(‘a’, ‘b’), (‘c’, ‘d’), (‘e’, ‘f’)] After the long consideration, I understand the code at last. The python…
the asterik * in python
Asterik in python is usually very confused for the beginner. Some times it appears one time before a variable like *args, some times it appears two times like **args. Usually it appears in function definition: * and ** allow arbitrary…