[Python] MemoryError: Unable to allocate array with shape and data type object

I want to perform an inner join between two dataset which looks like:

theme_ids.head()
id Loan Theme ID Loan Theme Type Partner ID
0 638631 a1050000000skGl General 151
1 640322 a1050000000skGl General 151
2 641006 a1050000002X1ij Higher Education 160
3 641019 a1050000002X1ij Higher Education 160
4 641594 a1050000002VbsW Subsistence Agriculture 336


and

theme_reg.head()
Partner ID Field Partner Name sector Loan Theme ID Loan Theme Type country forkiva region geocode_old ISO ... amount LocationName geocode names geo lat lon mpi_region mpi_geo rural_pct
0 9 KREDIT Microfinance Institution General Financial Inclusion a1050000000slfi Higher Education Cambodia No Banteay Meanchey (13.75, 103.0) KHM ... 450 Banteay Meanchey, Cambodia [(13.6672596, 102.8975098)] Banteay Meanchey Province; Cambodia (13.6672596, 102.8975098) 13.667259 102.897507 Banteay Mean Chey, Cambodia (13.6672596, 102.8975098) 90
1 9 KREDIT Microfinance Institution General Financial Inclusion a10500000068jPe Vulnerable Populations Cambodia No Battambang Province NaN KHM ... 20275 Battambang Province, Cambodia [(13.0286971, 102.989615)] Battambang Province; Cambodia (13.0286971, 102.989615) 13.028697 102.989616 Banteay Mean Chey, Cambodia (13.6672596, 102.8975098) 90
2 9 KREDIT Microfinance Institution General Financial Inclusion a1050000000slfi Higher Education Cambodia No Battambang Province NaN KHM ... 9150 Battambang Province, Cambodia [(13.0286971, 102.989615)] Battambang Province; Cambodia (13.0286971, 102.989615) 13.028697 102.989616 Banteay Mean Chey, Cambodia (13.6672596, 102.8975098) 90
3 9 KREDIT Microfinance Institution General Financial Inclusion a10500000068jPe Vulnerable Populations Cambodia No Kampong Cham Province (12.0, 105.5) KHM ... 604950 Kampong Cham Province, Cambodia [(12.0982918, 105.3131185)] Kampong Cham Province; Cambodia (12.0982918, 105.3131185) 12.098291 105.313118 Kampong Cham, Cambodia (11.9924294, 105.4645408) 90
4 9 KREDIT Microfinance Institution General Financial Inclusion a1050000002X1Uu Sanitation Cambodia No Kampong Cham Province (12.0, 105.5) KHM ... 275 Kampong Cham Province, Cambodia [(12.0982918, 105.3131185)] Kampong Cham Province; Cambodia (12.0982918, 105.3131185) 12.098291 105.313118 Kampong Cham, Cambodia (11.9924294, 105.4645408) 90


I've tried:

data = pd.merge(theme_ids, theme_reg, on='Partner ID', how='inner')


which raises:

MemoryError: Unable to allocate array with shape (15, 144356281) and data type object
​

Continue reading...