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add a 1-based seqence column to a petl table
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| ''' | |
| Versioned here: | |
| https://gist.github.com/kwmiebach/362a41b0fbf0cad6db36a1e037bcfbe6 | |
| ''' | |
| def add_seq(tab,name='seq',position=0): | |
| # NO, PETL IS CURRENTLY BROKEN - depending on python version | |
| # tab = ETL.addrownumbers(tab, 'seq') | |
| import petl as ETL | |
| inner = _add_seq_gen(tab,name,position) | |
| return ETL.wrap(inner) | |
| def _add_seq_gen(tab,name='seq',position=0): | |
| # Adds a new column with the given name | |
| # default name: 'seq' at the given position | |
| # (default: most left position). | |
| # The content is a 1 based sequence number. | |
| # You can use negative position to count from the right. | |
| # Make it iterable: | |
| itab = iter(tab) | |
| # Get first row (header) | |
| hd_list = next(itab, None) | |
| if hd_list is None: | |
| # empty table -> return an empty table | |
| # this is done by not yielding anything. hopefully this is ok. | |
| return | |
| # insert name at position | |
| hd_list = list(hd_list) | |
| hd_count = len(hd_list) | |
| # position = 0 means most left position | |
| # fix negative position or position > hd_count | |
| if position < 0: | |
| position = hd_count + position + 1 | |
| if position < 0: | |
| position = 0 | |
| if position > hd_count: | |
| position = hd_count | |
| hd_list.insert(position, name) | |
| yield tuple(hd_list) | |
| # all remaining rows: | |
| for idx, row in enumerate(itab, 1): # start enumerate from 1 as you want 1-based sequence | |
| row_as_list = list(row) | |
| row_as_list.insert(position, idx) | |
| yield tuple(row_as_list) |
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