[FIXED] pandas insert a string and a list into the dataframe

Issue

I made this code that allows me to create a table in an excel file. Only I wanted to add at the beginning of the column a string and then afterwards attach a list of elements to it.

def CreateExcel(metric,consumo, writer):
    df = pd.DataFrame({
        'metricID': metric,
        'consumo' : consumo,
    })
    df = df.sort_values('consumo', ascending=False)
    df.to_excel(writer, sheet_name="foglio1", startrow=1, header=False, index=False)
    workbook = writer.book
    worksheet = writer.sheets["foglio1"]
    (max_row, max_col) = df.shape
    column_settings = [{"header":column} for column in df.columns]
    worksheet.add_table(0, 0, max_row, max_col - 1, {"columns":column_settings})
    worksheet.set_column(0, max_col - 1, 70)

this is the working code, but I would like to add a string like this

df = pd.DataFrame({
        'metricID': "timeframe" + metric,
        'consumo' : "2022-11-10 2022-12-10" + consumo,
    })

python does not give me a syntax error, but in running the code it gives me this error:

    'metricID': "timeframe" + metric,
            ~~~~~~~~~~~~^~~~~~~
TypeError: can only concatenate str (not "list") to str

keeping in mind that the elements in the list are sorted in the function later on, I need to have those two strings be at the beginning of the table, so that then they are not put randomly in the list

Solution

We cannot reproduce without actual data, but I understand your question such that consumo and metric are lists that you want to extend by strings. So this is not a problem with pandas but a general one:

s = "hello"
l = ["world"]
result = [s] + l # concatenate the string (as a list) with an existing list
print(result)  # ["hello", "world"]

so the changes in your code are only subtle. Note that I added the list brackets to turn your string into a list.

def CreateExcel(metric,consumo, writer):
    df = pd.DataFrame({
        'metricID': ["timeframe"] + metric,
        'consumo' : ["2022-11-10 2022-12-10"] + consumo,
    })
    df = df.sort_values('consumo', ascending=False)
    df.to_excel(writer, sheet_name="foglio1", startrow=1, header=False, index=False)
    workbook = writer.book
    worksheet = writer.sheets["foglio1"]
    (max_row, max_col) = df.shape
    column_settings = [{"header":column} for column in df.columns]
    worksheet.add_table(0, 0, max_row, max_col - 1, {"columns":column_settings})
    worksheet.set_column(0, max_col - 1, 70)

Answered By - Klops