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Multiply entire column with a constant with pandas in python
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Multiply entire column with a constant with pandas in python
#1
I want to multiply '1' column which is numbered automatically as (0,1,2,3). I am getting "KeyError: 1".
What's wrong in my codes?
inpExcelFile = 'data_' + gridCells[str(i+1)][j].replace(', ', '_') + '.csv'  
            df = pd.read_csv(inpExcelFile, delimiter=' ')
            df = df ['1'] * 10000
            df.to_csv('word.csv', header=False, index=False)
Thank you.
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#2
If your dataframe is read with no headers then your index will be an integer, not a string.

For example take this data saved as fake.csv
Output:
4, 2, 6, 7, 4, 8 8, 1, 5, 4, 2, 7
We can multiply the second column like so:
import pandas as pd

myfile = open("fake.csv")
df = pd.read_csv(myfile, header=None)

print(df, end="\n\n")

df[1] *= 100

print(df)
Output:
Output:
0 1 2 3 4 5 0 4 2 6 7 4 8 1 8 1 5 4 2 7 0 1 2 3 4 5 0 4 200 6 7 4 8 1 8 100 5 4 2 7
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