确定 object 是字符串还是 dataframe

Question

I have some variables and single column dataframes.

I'm trying to arrange them (concat) into a single dataframe.

The problem is that some are single strings, some single column dataframes and I'm trying to loop through them, so I have to use different methods for the different types.

I've tried the following to determine if a single string or a dataframe is being passed.

data = {'Column Name':  ['First value', 'Second value']}
a_dataframe = pd.DataFrame (data, columns = ['Column Name'])

a_single_string = 'text'
another_string = 'more text'

feature_cols = ['a_single_string', 'a_dataframe', 'another_string']

for column in feature_cols:
    if column in locals():
        if isinstance(column, str):
            print("str: " + column)

        elif isinstance(column, pd.DataFrame):
            print("df: " + column)

But it sees the strings and dataframe as strings.
Any solutions?

Answer 1

Your code defines feature_cols as a list of strings. So your isinstance() test is returning the type of the string 'a_dataframe' , which is not the same thing as the variable a_dataframe .

This will fix your test:

feature_cols = [a_single_string, a_dataframe, another_string]

You also won't be able to do if column in locals(): because that expects the name as a string (as in your original code) not the variable.