如何使用多个 numpy 1d 数组创建一个 Pandas DataFrame?

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时间:2020-09-14 04:08:07  来源:igfitidea点击:

How to create a pandas DataFrame with several numpy 1d arrays?

pythonarrayspandasnumpy

提问by laurenz

I've created some np.arrays to do some calculation with them. (All have the same size [100,1]) Now I want to create a pandas Dataframe and each array shoud be one column of that DF. The Names of the arrays should be the header of the DataFrame.

我创建了一些 np.arrays 来对它们进行一些计算。(都具有相同的大小 [100,1])现在我想创建一个 Pandas Dataframe,并且每个数组都应该是该 DF 的一列。数组的名称应该是 DataFrame 的标题。

In Matlab I would easily do it like that:

在 Matlab 中,我会很容易地这样做:

Table = table(array1, array2, array3, ... );

Table = table(array1, array2, array3, ... );

How can I do this in Python?

我怎样才能在 Python 中做到这一点?

thanks in advance!

提前致谢!

回答by ayhan

Let's say these are your arrays:

假设这些是您的数组:

arr1, arr2, arr3 = np.zeros((3, 100, 1))

arr1.shape
Out: (100, 1)

You can use hstackto stack them and pass the resulting 2D array to the DataFrame constructor:

您可以使用hstack来堆叠它们并将生成的二维数组传递给 DataFrame 构造函数:

df = pd.DataFrame(np.hstack((arr1, arr2, arr3)))

df.head()
Out: 
     0    1    2
0  0.0  0.0  0.0
1  0.0  0.0  0.0
2  0.0  0.0  0.0
3  0.0  0.0  0.0
4  0.0  0.0  0.0

Or name the columns as arr1, arr2, ...:

或将列命名为arr1, arr2, ...:

df = pd.DataFrame(np.hstack((arr1, arr2, arr3)), 
                  columns=['arr{}'.format(i+1) for i in range(3)])

which gives

这使

df.head()
Out: 
   arr1  arr2  arr3
0   0.0   0.0   0.0
1   0.0   0.0   0.0
2   0.0   0.0   0.0
3   0.0   0.0   0.0
4   0.0   0.0   0.0

回答by jezrael

Solution with numpy.concatenatefor 2d array and DataFrameconstructor:

numpy.concatenate二维数组和DataFrame构造函数的解决方案:

df = pd.DataFrame(np.concatenate([arr1, arr2, arr3], axis=1), columns= ['a','b','c'])