AttributeError: 'numpy.ndarray' object has no attribute 'apply'

Question

Department = input("Is there a list you would like to view")


readfile = pd.read_csv('6.csv')
filevalues= readfile.loc[readfile['Customer'].str.contains(Department, na=False), 'June-18\nQty'] 
filevalues = filevalues.fillna(int(0))

int_series = filevalues.values.astype(int) 
calculated_series = int_series.apply(lambda x: filevalues*1.3)


print(filevalues)

I am getting this error : AttributeError: 'numpy.ndarray' object has no attribute 'apply'

I have looked through this website and no solutions seems to work. I simply want to multiply the data by 1.3 in this series. Thank you

Answer 1

There's two issues here.

1. By taking .values you actually access the underlying numpy array; you no longer have a pandas.Series. numpy arrays do not have an apply method.
2. You are trying to use apply for a simple multiplication, which will be orders of magnitude slower than using a vectorized approach.

See below:

import pandas as pd
import numpy as np

df = pd.DataFrame({'a': np.arange(1000, dtype=np.float64)})
print(type(df['a']))
# Gives pandas.core.series.Series

print(type(df['a'].values))
# Gives numpy.ndarray

# The vectorized approach
df['a'] = df['a'] * 1.3