python pandas将数据框展平为列表

python pandas flatten a dataframe to a list

提问by jason

I have a df like so:

我有一个像这样的 df：

import pandas
a=[['1/2/2014', 'a', '6', 'z1'], 
   ['1/2/2014', 'a', '3', 'z1'], 
   ['1/3/2014', 'c', '1', 'x3'],
   ]
df = pandas.DataFrame.from_records(a[1:],columns=a[0])

I want to flatten the df so it is one continuous list like so:

我想展平 df 所以它是一个连续的列表，如下所示：

['1/2/2014', 'a', '6', 'z1', '1/2/2014', 'a', '3', 'z1','1/3/2014', 'c', '1', 'x3']

['1/2/2014', 'a', '6', 'z1', '1/2/2014', 'a', '3', 'z1','1/3/2014', 'c', '1', 'x3']

I can loop through the rows and extendto a list, but is a much easier way to do it?

我可以遍历行和extend列表，但有更简单的方法吗？

采纳答案by Saullo G. P. Castro

You can just use .flatten()on the DataFrame:

您可以只.flatten()在 DataFrame 上使用：

df.values.flatten()

and you can also add .tolist()if you want the result to be a Python list.

.tolist()如果您希望结果为 Python ，您也可以添加list。

Edit

编辑

As suggested in the comments, now .to_numpy()is recommended instead of .values.

正如评论中.to_numpy()所建议的那样，推荐使用now而不是.values。

回答by Chitrasen

You can try with numpy

你可以试试 numpy

import numpy as np
np.reshape(df.values, (1,df.shape[0]*df.shape[1]))

回答by meloncholy

Maybe use stack?

也许使用堆栈？

df.stack().values
array(['1/2/2014', 'a', '3', 'z1', '1/3/2014', 'c', '1', 'x3'], dtype=object)

(Edit:Incidentally, the DF in the Q uses the first row as labels, which is why they're not in the output here.)

（编辑：顺便说一句，Q 中的 DF 使用第一行作为标签，这就是为什么它们不在此处的输出中。）