TypeError: string indices must be integers when using .apply

I have this simple function:

def q1(x):
    if x['How likely are you to recommend us to a colleague?'] =='Extremely likely':
        return 10
    if x['How likely are you to recommend us to a colleague?']=='Not at all likely':
        return 0
    else:
        return x

The other values are from 1-9.
I’ve tried variations of the below, but I always get the same error

df.loc[:,'How likely are you to recommend us to a colleague?']=df['How likely are you to recommend us to a colleague?'].apply(q1)

I’ve also tried putting 10 and 0 in brackets (return "10" and return "0")

I’ve tried creating a new column instead of replacing but the error is the same.

TypeError: string indices must be integers

>Solution :

Thy this:

def q1(x):
    if x == 'Extremely likely':
        return 10
    if x == 'Not at all likely':
        return 0
    return x

df['How likely are you to recommend us to a colleague?'] = df['How likely are you to recommend us to a colleague?'].apply(q1)

Example:

import pandas as pd

df = pd.DataFrame(
    {
        "How likely are you to recommend us to a colleague?": [
            "Extremely likely",
            "Extremely likely",
            "Not at all likely",
            "Not at all likely",
            "Somewhat likely",
        ]
    }
)
df['How likely are you to recommend us to a colleague?'] = df['How likely are you to recommend us to a colleague?'].apply(q1)
print(df)
# Prints:
"""
  How likely are you to recommend us to a colleague?
0                                                 10
1                                                 10
2                                                  0
3                                                  0
4                                    Somewhat likely
"""