一些基礎算法（含疑問）

print set("as").issubset("usa")  : 檢查"as"是否"usa"的子集

print 'AB'.lower() 

print 'AB'.upper() 變換大小寫

grid = [[1,0,0], [0,1,0]]
grid_ext = [''.join(str(x) for x in row) for row in grid]
print grid

print grid_ext

output:

[[1, 0, 0], [0, 1, 0]]
['100', '010']

print zip(*grid)

output:

[(1, 0), (0, 1), (0, 0)]

print map(list, zip(*grid))

output:

[[1, 0], [0, 1], [0, 0]]

for key, val in dic.items():
        if val == 1:
            return key尋找 val == 1 的對應的key

train_x_flatten = train_x_orig.reshape(train_x_orig.shape[0], -1).T  
什麼意思 不懂應該是變成一行再轉秩