start index at 1 for Pandas DataFrame

Index is an object, and default index starts from 0:

>>> result.index
Int64Index([0, 1, 2], dtype=int64)

You can shift this index by 1 with

>>> result.index += 1 
>>> result.index
Int64Index([1, 2, 3], dtype=int64)

Just set the index before writing to CSV.

df.index = np.arange(1, len(df))

And then write it normally.

source: In Python pandas, start row index from 1 instead of zero without creating additional column

Working example:

import pandas as pdas
dframe = pdas.read_csv(open(input_file))
dframe.index = dframe.index + 1

Another way in one line:

df.shift()[1:]

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