numpy, pandas,collections.Counter
--------------------------numpy---------------------------------------------
1.产生随机矩阵:np.random.rand(2,3,5)
产生整形矩阵:np.random.randint(0,10,(4,3))
正态分布:np.random.binomial(5, 0.5, size=(2,3))
2.搜索最大数,np.max(a,axis=0)
搜索最大数位置: np.where
3.保存到txt,np.savetxt()
-----------------------------pandas ------------------------------------------------
1.读取csv: pd.read_csv
2.合并dataframe: pd.concat(df1,df2), 参数见链接https://www.cnblogs.com/guxh/p/9451532.html
3.onehot 其中几列: pd.get_dummies(df, columns = ["s"])
或者 size_mapping = {'XL': 3, 'L': 2,'M': 1}
df['size'] = df['size'].map(size_mapping
4.转化成list: df.values.tolist()
-------------------------------collections--------------------------------------
1.Counter :
Counter