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pythonmultiprocessingpool

TypeError: object of type 'IMapIterator' has no len() for pool.imap

I am getting following error:

df_OP = pd.DataFrame([excel_write_data[idx].__dict__ for idx in range(0, 
len(excel_write_data))])

TypeError: object of type 'IMapIterator' has no len().

I am using imap for parrallel processing but I am getting above error 

excel_write_data = pool.imap(pre_process, excel_read_data)

How can i overcome this error . can any one help

Solution

  • So IMapIterator is an iterable, but you need something that acts like a list (has a len()). So, make it a list:

    excel_write_data = list(pool.imap(pre_process, excel_read_data))