assert to check the value available in the column of dataframe-CodePudding

def director_release_year(director_df,filter_column,director_name):
    if filter_column not in director_df.columns:
        raise Exception("the column is not available in the DataFrame")
    # Tests that the the column value is in the dataframe
    if director_name in director_df[filter_column].tolist()== False:
           raise ValueError("the column don't have the value")
    
    #filter the dataframe based on the given director_name
    df=director_df[director_df[filter_column]==director_name]
    
    # return the result
    return df

if i give the unavailable value for director_name the output is a empty df instead of this exception error

    movie_title release_date    hero    villian song    name    director    release_year

I tried the following assert , but the result is one or other error not the exact assert i set for

 assert director_name in director_df[director_name].values,"The name does not exist in the director column"
o/p:

KeyError: 'siva'


 assert director_df[filter_column].isin([director_name]),"The name does not exist in the director column"
o/p:

The truth value of a Series is ambiguous. Use a.empty, a.bool(), a.item(), a.any() or a.all().

CodePudding user response：

I think you can write

if (director_df[filter_column] != director_name).all():
    raise ValueError("the column don't have the value")

The condition above basically checks if all values in director_df[filter_column] does not equal director_name.

CodePudding user response：

As you are checking a string director_name in a dataframe director_df, it results in a series of bool values. So its better to check for conditionality using .any() or .all(). This concept is clearly explained in this Reference link.

if not (director_df['filter_column'] == director_name).any():
    raise ValueError