When importing historical price data for several securities using get_historical(), the ordering of securities is not as specified in the function. I have found it to be arbitrary which is annoying. Sample code here below.
import pandas as pd
import tia.bbg.datamgr as dm
mgr = dm.BbgDataManager()
sids = mgr[['SPGCCIP Index', 'SPGCCLP Index', 'SPGCGCP Index', 'SPGCSIP Index']]
df = sids.get_historical('PX_LAST', '1-Jan-2014', '31-Jan-2014')
#Problem is the order of columns in Dataframe is not consistent with order of sids
print df