Changing Column type using astype does not work

I need to make a join into tables, and for that, I need to make a column type change but Is not changing. This is my code, the dataset is open source.

import pandas as pd
import json

#Get Data
url = 'https://raw.githubusercontent.com/sthemonica/alura-voz/main/Dados/Telco-Customer-Churn.json'
response = urlopen(url)
strfile = response.read().decode('utf-8', 'replace')
jsonfile = json.loads(strfile)
dft = pd.json_normalize(data=jsonfile)

# My Problem
print('Before', dft['Churn'].dtypes)
dft = dft.astype({'Churn': str})
print('After', dft['Churn'].dtypes)

Result:

Before object
After object

note, I also try:

dft = dft.astype({'Churn': "str"})
dft.astype({'Churn': "str"})
dft.astype({'Churn': str})

What I'm doing wrong? This is the join a what to do:

dtemp = [[0, 'No'],
     [1, 'Yes']]
columns_names = ['Id', 'Churn']
df_FromTo = pd.DataFrame(data=dtemp, columns=columns_names)
dft = dft.join(df_FromTo, on='Churn', rsuffix="_del")

Result:

ValueError: You are trying to merge on object and int64 columns. If you wish to proceed you should use pd.concat

CodePudding user response：

 dft = dft.merge(df_FromTo, on='Churn')

CodePudding user response：

See pandas.DataFrame.join on argument explanation

Column or index level name(s) in the caller to join on the index in other, otherwise joins index-on-index.

When you do dft.join(df_FromTo, on='Churn', rsuffix="_del"), caller is dft, other is df_FromTo, you are joining with dft['Churn'] with df_FromTo.index

You can fix with

dft = dft.join(df_FromTo.set_index('Churn'), on='Churn', rsuffix="_del")