See this SO question

The docstring should indicate what is not being copied unnecessarily (Indexes, ndarrays, etc.)

Comment From: jreback

IIRC I think the copy parameter only matters here is its a trivial merge and you actually do want it copied (kind I like a reindex with the same index)

Comment From: cpcloud

yep here's the explanation:

if the index join is the same as both indexes in the join it will return None for the indexers and when _JoinUnit.reindex_block is called copy will only take effect if the indexer is None which means what you said: trivial merge

Comment From: cpcloud

still should say something about that....definitely not what i just wrote but something more informative than what's there

Comment From: moaraccounts

take

Comment From: moaraccounts

@jreback @cpcloud I'm having trouble understanding how editing the merge copy parameter documentation resolves this. In the original SO question, OP is using concat, not merge.

It seems like the concat copy parameter needs adjustment, as running through the example from this indicates:

Note It is worth noting that concat() (and therefore append()) makes a full copy of the data, and that constantly reusing this function can create a significant performance hit. If you need to use the operation over several datasets, use a list comprehension.

Maybe I'm missing something?

Comment From: jangorecki

@moaraccounts Maybe this issue is just asking for a different thing than linked SO is about. I subscribed to this issue seeking better "merge" "copy" documentation, not a "concat" copy.

Comment From: TheMellyBee

Can this be closed?

Comment From: Pavanvan

Hi, I'm a new contributor and would like to take this on as my first issue. Could you please assign it to me?

Comment From: jangorecki

Hi, I'm a new contributor and would like to take this on as my first issue. Could you please assign it to me?

Do you know what needs to be done here exactly?