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

@RafaelC I was attempting to multiply every value in my list by 1.3. I used this method because supposedly it is supposed to convert the series into an int. — Michael Norman
– Michael Norman, Commented Jul 17, 2018 at 18:27
int_series * 1.3 does multiply every value in the series by 1.3 — roganjosh
– roganjosh, Commented Jul 17, 2018 at 18:30
@roganjosh Okay, but then do you know the reason for my error? — Michael Norman
– Michael Norman, Commented Jul 17, 2018 at 18:30
The reason is simple: there is no apply function in numpy arrays. There are, though, in pandas.Series objects, which you would have if you did filevalues.astype(int) instead of filevalues.values.astype(int) — rafaelc
– rafaelc, Commented Jul 17, 2018 at 18:32

roganjosh · Accepted Answer · 2018-07-17 18:40:14Z

1

There's two issues here.

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.
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

answered Jul 17, 2018 at 18:40

roganjosh

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Min4t0 · Accepted Answer · 2018-07-17 18:39:40Z

0

numpy.ndarray does not have the 'apply' attribute. https://docs.scipy.org/doc/numpy/reference/generated/numpy.ndarray.html

answered Jul 17, 2018 at 18:39

Min4t0

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