CODEWITHSUNDEEP
pythonnumpypython-3.6
Mass17
Mass17

Reputation: 1605

Adding up the values with the same index using numpy/python

I am a newbie to python and numpy. I want to find the total rainfall days (ie. sum of column E for each year, attach the image herewith). I am using numpy.unique to find the unique elements of array year.

following is my attempt;

import numpy as np
data = np.genfromtxt("location/ofthe/file", delimiter = " ")
unique_year = np.unique(data[:,0], return_index=True)
print(unique_year)
j= input('select one of the unique year: >>>  ')
#Then I want to give the sum of the rainfall days in that year.

I would appreciate if someone could help me. Thanks in advance.

enter image description here

Upvotes: 1

Views: 77

Answers (1)

jpp
jpp

Reputation: 164673

For such tasks, Pandas (which builds on NumPy) is more easily adaptable.

Here, you can use GroupBy to create a series mapping. You can then use your input to query your series:

import pandas as pd

# read file into dataframe
df = pd.read_excel('file.xlsx')

# create series mapping from GroupBy object
rain_days_by_year = df.groupby('year')['Rain days(in numbers)'].sum()

# get input as integer
j = int(input('select one of the unique year: >>>  '))

# extract data
res = rain_days_by_year[j]

Upvotes: 1

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