How to replace a value in python pandas using a for loop

Question

I am analyzing data from an experiment, and have to combine measurements from two devices (variables "data" and "behavioral").

I want to be able to walk through the recordings in the "data" data frame, and then, if a specific condition is met (if x == Stimulus/S 2), I want it to be replaced with the corresponding value in the "behavior" datarame.

This is my code so far:

import os
import csv
import pandas as pd

os.chdir('C:/Users/eeg1/Desktop/NSM-Pilot')

col_names2 = ['Stimulus Name', 'Stimulus Content', 'Trials', 'This Rep Number', 'trials.thisTrialN', 'trials.thisN', 'trials.thisIndex', 'Button Box Keys', 'Button Box RT', 'Date', 'Frame Rate', 'expName', 'Session', 'Participant' ]
behavioral = pd.read_csv('NSM-01-behavioral.csv', names=col_names2, skiprows=[0])
counter2 = 0
for y in behavioral['Stimulus Content']:
    counter2 += 1

col_names = ['Event Number', 'Onset', 'Duration', 'Description']
data = pd.read_csv(r'NSM-01-01.csv', names=col_names, skiprows=[0])
counter = 0
for x in data['Description']:
    if x == 'Stimulus/S  2':
        x = behavioral['Stimulus Content'][counter]
        counter += 1

The problem is that this part seems to have no effect:

x = behavioral['Stimulus Content'][counter]

Please see https://stackoverflow.com/questions/20109391/how-to-make-good-reproducible-pandas-examples -- there's no point referencing a csv file we don't have access to. — butterflyknife, Dec 15 '21 at 08:11
Try: `data.loc[data['Description'] == 'Stimulus/S 2', 'Description'] = behavioral['Stimulus Content']`? — Corralien, Dec 15 '21 at 08:24
Update your post with the output of `behavioral.head(5)` and `data.head(5)` please to get help. — Corralien, Dec 15 '21 at 08:26

How to replace a value in python pandas using a for loop

0 Answers0