Creating a Pandas DataFrame from a Numpy array: How do I specify the index column and column headers?

Question

I have a Numpy array consisting of a list of lists, representing a two-dimensional array with row labels and column names as shown below:

data = array([['','Col1','Col2'],['Row1',1,2],['Row2',3,4]]) 

I'd like the resulting DataFrame to have Row1 and Row2 as index values, and Col1, Col2 as header values

I can specify the index as follows:

df = pd.DataFrame(data,index=data[:,0]), 

however I am unsure how to best assign column headers.

Answer 1

You need to specify data, index and columns to DataFrame constructor, as in:

>>> pd.DataFrame(data=data[1:,1:],    # values ...              index=data[1:,0],    # 1st column as index ...              columns=data[0,1:])  # 1st row as the column names 

edit: as in the @joris comment, you may need to change above to np.int_(data[1:,1:]) to have correct data type.