python - Pandas DataFrame Advanced Slicing -

i r user , found myself struggling bit moving python, indexing capabilities of pandas.

household_id second column. sorted dataframe based on column , ran following instructions, returning various results (that expect same). expressions same? if so, why see different results?

in [63]: ground_truth.columns out[63]: index([timestamp, household_id, ... (continues)  in [59]: ground_truth.ix[1107177,'household_id'] out[59]: 2  in [60]: ground_truth.ix[1107177,1] out[60]: 2.0  in [61]: ground_truth.iloc[1107177,1] out[61]: 4.0  in [62]: ground_truth['household_id'][1107177] out[62]: 2 

ps: cant post data unfortunately (too big).

note: when sort column, you'll rearrange index, , assuming wasn't sorted way begin you'll have integers labels don't equal linear index in array.

first, ix first try integers labels indices, immediate 59 , 62 same. second, if index not 0:n - 1 1107177 label, not integer index difference between 60 , 61. far float casting goes, looks might using older version of pandas. doesn't happen in git master.

here docs on ix.

here's example toy dataframe:

in [1]:  df = dataframe(randn(10, 3), columns=list('abc')) print df print print df.sort('a')                      b          c 0      -1.80      -0.28      -1.10 1      -0.58       1.00      -0.48 2      -2.50       1.59      -1.42 3      -1.00      -0.12      -0.93 4      -0.65       1.41       1.20 5       0.51       0.96       1.28 6      -0.28       0.13       1.59 7       1.28      -0.84       0.51 8       0.77      -1.26      -0.50 9      -0.59      -1.34      -1.06                      b          c 2      -2.50       1.59      -1.42 0      -1.80      -0.28      -1.10 3      -1.00      -0.12      -0.93 4      -0.65       1.41       1.20 9      -0.59      -1.34      -1.06 1      -0.58       1.00      -0.48 6      -0.28       0.13       1.59 5       0.51       0.96       1.28 8       0.77      -1.26      -0.50 7       1.28      -0.84       0.51 

notice sorted row indices integers , don't map locations.