Python Pandas AttributeError: 'str' object has no attribute 'isin'

First question here. I am attempting to use pandas to create a new column ('zone') in my dataframe based on the values of other columns in my dataframe. I am using address data.

Here is some sample data, my real dataset has 25k rows. sample_df:

Shipping City Shipping Zip State DISTRICT NAME Garden City 11530 NY NEW YORK 2 San Francisco 94117 CA CALIFORNIA 1 Frisco 75036 TX TEXAS 1 Las Vegas 89139 NV NV-UT Beverly Hills 90212 CA CALIFORNIA 5 

here is sample criteria for the new column:

In general if in mid west or east coast I can use state to assign the zone. for NY: zone_8 TX: zone_6 For California, I want to split into 3 different zones: NorCal, Socal, and central Cal -which will also include Las Vegas and Phoenix. I can use the given 'District Name' column to divide CA only. for special cities I can use 'Shipping City'. he rest of the sample expected results are below:

Expected Result:

 Shipping City | Shipping Zip | State | DISTRICT NAME | Zone ----- | ----- | ----- | ----- | ----- Garden City | 11530 | NY | NEW YORK 2 | zone_8 San Francisco | 94117 | CA | CALIFORNIA 1 | zone_3 Frisco | 75036 | TX | TEXAS 1 | zone_6 Las Vegas | 89139 | NV | NV-UT | zone_2 Beverly Hills | 90212 | CA | CALIFORNIA 5 | zone_2 

I created lists for my expected values:

zone8_state = ['ME', 'NH', 'VT', 'MA', 'RI', 'CT', 'AA', 'HI', 'NY', 'PA', 'NJ', 'MD', 'DE', 'WV', 'OH', 'VA', 'NC', 'SC', 'GA', 'FL', 'MI'] zone7_state = ['KY', 'IN', 'IL', 'WI', 'MN', 'TN', 'AL','LA', 'MS', 'AR'] zone6_state = ['IA', 'MO', 'ND', 'SD', 'NE', 'KS', 'OK', 'TX'] zone5_state = ['MT', 'WV', 'CO', 'NM', 'ID', 'WA', 'OR'] zone4_state = ['UT', 'NV', 'AZ'] norcal = ['CALIFORNIA 1', 'CALIFORNIA 2'] socal = ['CALIFORNIA 4', 'CALIFORNIA 5'] zone3_city = ['CALIFORNIA 3', 'Las Vegas', 'Phoenix'] 

Then I made a function:

def get_zones(sample_df): if sample_df['State'].isin(zone8_state): return 'zone_8' elif sample_df['State'].isin(zone7_state): return 'zone_7' elif sample_df['State'].isin(zone6_state): return 'zone_6' elif sample_df['State'].isin(zone5_state): return 'zone_5' elif sample_df['State'].isin(zone4_state) | sample_df['DISTRICT NAME'].isin(norcal): return 'zone_4' elif sample_df['DISTRICT NAME'].isin(zone3_city) | sample_df['Shipping City'].isin(zone3_city): return 'zone_3' elif sample_df['DISTRICT NAME'].isin(socal): return 'zone_2' else: return 'check the record' 

THen I applied the function to my df:

sample_df['zone'] = sample_df.apply(get_zones, axis=1) 

after I apply though, I get this:

AttributeError: 'str' object has no attribute 'isin'

can you please help me to get my function to work correctly? I also tried using 'contains' instead of 'isin' but also get a similar Attribute error. Thanks.

1 Answer

Think of it like this: when you call .apply with axis=1, the DataFrame gets passed to your get_zones function on a row-by-row basis, and the function will operate on each row individually. So within the get_zones() function, sample_df["State"] (or any other column you index) is a single (str) value corresponding to a specific row's entry for that column. Given this, you could modify your function to use Python's built-in in keyword, since you're just doing a simple membership check. In other words, instead of if sample_df['State'].isin(zone8_state):, try if sample_df['State'] in zone8_state: and so on.

Alternatively, you could abandon .apply and restructure get_zones() to return a list or array of zones corresponding to the rows of the input DataFrame, then just do sample_df["zone"] = get_zones(sample_df).