T Test on Multiple Columns in Dataframe

Question

Dataframe looks something like:

decade     rain     snow
1910       0.2      0.2
1910       0.3      0.4
2000       0.4      0.5
2010       0.1      0.1

I'd love some help with a function in python to run a t test comparing decade combinations for a given column. This function works great except does not take an input column such as rain or snow.

from itertools import combinations

def ttest_run(c1, c2):
    results = st.ttest_ind(cat1, cat2,nan_policy='omit')
    df = pd.DataFrame({'dec1': c1,
                       'dec2': c2,
                       'tstat': results.statistic,
                       'pvalue': results.pvalue}, 
                       index = [0])    
    return df

df_list = [ttest_run(i, j) for i, j in combinations(data['decade'].unique().tolist(), 2)]

final_df = pd.concat(df_list, ignore_index = True)