In python pandas, how can I re-sample and interpolate a DataFrame?

Assuming column 1 is in the index, you can reindex your dataframe with the original values along with the list you created and then use interpolate to fill in the nan's.

df1 = df.reindex(df.index.union(np.linspace(.11,.25,8)))
df1.interpolate('index')

               2         3         4
0.1100  0.000000  1.000000  5.000000
0.1300  0.000069  0.891794  1.453094
0.1323  0.000077  0.879350  1.045200
0.1500  0.000363  0.793832  0.574093
0.1545  0.000435  0.772090  0.454320
0.1700  0.000976  0.702472  0.325482
0.1768  0.001213  0.671930  0.268960
0.1900  0.001999  0.616698  0.218675
0.1990  0.002535  0.579040  0.184390
0.2100  0.003517  0.537127  0.161364
0.2213  0.004526  0.494070  0.137710
0.2300  0.004526  0.494070  0.137710
0.2500  0.004526  0.494070  0.137710