pandas comparison raises TypeError: cannot compare a dtyped [float64] array with a scalar of type [bool]

I have the following structure to my dataFrame: ``` Index: 1008 entries, Trial1.0 to Trial3.84 Data columns (total 5 columns): CHUNK_NAME 1008 non-null values LAMBDA 1008 non-null values BETA 1008 non-null values HIT_RATE 1008 non-null values AVERAGE_RECIPROCAL_HITRATE 1008 non-null values chunks=['300_321','322_343','344_365','366_387','388_408','366_408','344_408','322_408','300_408'] lam_beta=[(lambda1,beta1),(lambda1,beta2),(lambda1,beta3),...(lambda1,beta_n),(lambda2,beta1),(lambda2,beta2)...(lambda2,beta_n),........] my_df.ix[my_df.CHUNK_NAME==chunks[0]&my_df.LAMBDA==lam_beta[0][0]] ``` I want to get the rows of the DataFrame for a particular chunk lets say `chunks[0]` and particular `lambda` value. So in this case, the output should be all rows in the DataFrame having `CHUNK_NAME='300_321'` and `LAMBDA=lambda1`. There would be n rows one for each `beta` value that would be returned. But instead I get the following error. Any help in solving this problem would be appreciated. ``` TypeError: cannot compare a dtyped [float64] array with a scalar of type [bool] ```