python pandas flatten a dataframe to a list
Solution 1:
You can use .flatten() on the DataFrame converted to a NumPy array:
df.to_numpy().flatten()
and you can also add .tolist() if you want the result to be a Python list.
Edit
In previous versions of Pandas, the values attributed was used instead of the .to_numpy() method, as mentioned in the comments below.
Solution 2:
Maybe use stack?
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.)