Matching variable value in pandas CSV

Question

I have a CSV file with a list of Towns, Countys, and Country.

                Town           County  Country      
            Ampthill     Bedfordshire  England      
             Arlesey     Bedfordshire  England

I want to be able to check if a town is in the list, if a town is in the list then I want to know what the country is.
Currently using pandas.

Any thoughts on how to check if a variable value is present in pandas.

Asked By: Jack

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Source

Answer 1

try this :

import pandas as pd
df = pd.read_csv('YOUR_PATH_HERE')

# to check if a single town
country = df.loc[(df['Town'] == 'Arlesey')]['Country']

# using the isin() operator
df.loc[df['Town'].isin(['Arlesey'])]['Country']

output:

1    England

using isin() is a very powerful tool for what you are looking for. It takes a list and returns True if the value is in the list. If you want the entire dataframe, just remove ['Country] at the end:

     Town      County       Country
1   Arlesey Bedfordshire    England

If you need the actual values, you could use pd.series.values

# using values[0] because it is the first element in the array
df.loc[df['Town'].isin(['Arlesey'])]['Country'].values[0]

Answered By: MattR

Answer 2

If you just want the value at the corresponding intersection:

import pandas as pd

df = pd.read_csv('test.csv')

if 'ampthill' in df['town'].values:
    index = df.town[df.town == 'ampthill'].index.tolist()[0]
    country = df.loc[index, 'country']

print(country)
>>> england

Answered By: flevinkelming

Answer 3

So this worked for me…

from pathlib import Path
import pandas as pd
home = str(Path.home())
csv_folder = Path(r"TO_CSV_FOLDER")


csv =  csv_folder / 'town-county-country.csv'
town = 'Ampthill'
with open(csv,'r') as csv:
    ctu = ["Town","County","Country"]
    cas = pd.read_csv(csv,usecols=ctu)
    index = cas.Town[cas.Town == town].index.tolist()[0]
    named = cas.loc[index, 'Country']
    print(named)

Answered By: Daniel

Matching variable value in pandas CSV

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