Python Pandas ValueError DataFrame constructor not properly called

Question

I am trying to create a Python Pandas Dataframe using this code:

df1=pd.DataFrame('Email')

But I am getting this error:

ValueError: DataFrame constructor not properly called!

Answer 1

The syntax is not right. The right syntax is as follows:

Df1=pd.DataFrame(columns=[‘Email’])

Answer 2

You are providing a string representation of a dict to the DataFrame constructor, and not a dict itself. So this is the reason you get that error.

So if you want to use your code, you could do:

df = DataFrame(eval(data))

But better would be to not create the string in the first place, but directly putting it in a dict. Something roughly like:

data = []
for row in result_set:
    data.append({'value': row["tag_expression"], 'key': row["tag_name"]})

But probably even this is not needed, as depending on what is exactly in your result_set you could probably:

• provide this directly to a DataFrame: DataFrame(result_set)
• or use the pandas read_sql_query function to do this for you.

Answer 3

It seems you need list:

df2 = pd.DataFrame(['Test'])
print (df2)
      0
0  Test

EDIT:

It seems you need:

def multiple_dfs(file_name, sheet, *args):
    """
    Put multiple dataframes into one xlsx sheet
    """

    row=2
    writer = pd.ExcelWriter(file_name)

    df = pd.DataFrame({'user': ['Bob', 'Jane', 'Alice'], 
               'income': [40000, 50000, 42000]})
    df2 = pd.DataFrame({'amount': [100, 500, 1000], 
               'income': [40000, 50000, 42000]})
    df3 = pd.DataFrame(['Title'])

    df.to_excel(writer, sheet, startrow=row, index=False)
    row += len(df) + 1
    df2.to_excel(writer, sheet, startrow=row, index=False)
    df3.to_excel(writer, sheet, startrow=0, startcol=0, header=None, \
             index=False)

multiple_dfs('file.xlsx','Sheet1')