Per email from Brad Maggard on 2015-09-16, addfieldusingcontext() doe…

[rogerkwoodley]

Per email from Brad Maggard on 2015-09-16, addfieldusingcontext() doesn't have access to the new field, making calculations like running sum more complicated.

The generator yields the tuple from the original table. It now creates a new Record() object with the additional field and the previous row's value, providing access to the prior row's new field.

I profiled both time and memory usage - the extra step of creating the Record() instance is minimal.

On a random table of 1MM rows, it added 100KB of memory at runtime and changed execution time from 63 seconds to 65 seconds on my test.

[alimanfoo]

Thanks a lot Roger, I'll review asap.

On Wednesday, September 16, 2015, Roger Woodley notifications@github.com
wrote:

Per email from Brad Maggard on 2015-09-16, addfieldusingcontext() doesn't
have access to the new field, making calculations like running sum more
complicated.

The generator yields the tuple from the original table. It now creates a
new Record() object with the additional field and the previous row's value,
providing access to the prior row's new field.

I profiled both time and memory usage - the extra step of creating the
Record() instance is minimal.

On a random table of 1MM rows, it added 100KB of memory at runtime and

changed execution time from 63 seconds to 65 seconds on my test.

You can view, comment on, or merge this pull request online at:

#343
Commit Summary

• Per email from Brad Maggard on 2015-09-16, addfieldusingcontext()
  doesn't have access to the new field, making calculations like running sum
  more complicated.

File Changes

• M petl/test/transform/test_basics.py
  https://github.com/alimanfoo/petl/pull/343/files#diff-0 (33)
• M petl/transform/basics.py
  https://github.com/alimanfoo/petl/pull/343/files#diff-1 (5)

Patch Links:

• https://github.com/alimanfoo/petl/pull/343.patch
• https://github.com/alimanfoo/petl/pull/343.diff

—
Reply to this email directly or view it on GitHub
#343.

Alistair Miles
Head of Epidemiological Informatics
Centre for Genomics and Global Health http://cggh.org
The Wellcome Trust Centre for Human Genetics
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Oxford
OX3 7BN
United Kingdom
Web: http://purl.org/net/aliman
Email: alimanfoo@googlemail.com alimanfoo@gmail.com
Tel: +44 (0)1865 287721

[alimanfoo]

Thank you Roger, sorry it took so long to get to this.

[rogerkwoodley]

Oh, no need to apologize - you have your regular life, managing releases, etc. to worry about.