Python-如何将动态系列名称和DataFrame名称作为函数参数传递？

Question

I want to write a function that receives a Panda data-frame and a given series name and retrieves the unique values of this series and their frequencies in the dataset.

def getUniqueValuesByField(dataframe, fieldname):
    ''' Retrive for non-numerical series the unique values and their frequencies '''
    result = dataframe.fieldname.apply(lambda x: pd.Series(x)).unstack().value_counts(normalize=True, sort=True, ascending=False, bins=None, dropna=True)

    #dataframe[fieldname].unique()
    return  result

Then, I can call this function as following:

 df = pd.DataFrame.from_dict(RequestsDict)

getUniqueValuesByField(df, 'detected_language')
getUniqueValuesByField(df, 'detected_vertical')

Is it possible? I tried to concatenate strings and use the eval() function but i'm not sure this is the correct way to do that.

Answer 1

Use .value_counts() like so:

In [35]: df = pd.DataFrame(['foo','bar','baz', 'foo','bar'], columns=['test'])

In [36]: df['test'].value_counts()
Out[36]: 
foo    2
bar    2
baz    1
dtype: int64