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Better column names when unnamed objects passed to merge #248

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joshuaulrich opened this issue Jun 17, 2018 · 0 comments
Closed

Better column names when unnamed objects passed to merge #248

joshuaulrich opened this issue Jun 17, 2018 · 0 comments
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@joshuaulrich
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enhancement Enhancement to existing feature
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0.11-2

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@joshuaulrich
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The column names of a merge() result can be monstrous if raw, unnamed objects are passed to merge(). This can occur when merge() is called via do.call(). For example:

data(sample_matrix)
x <- as.xts(sample_matrix)
d <- setNames(lapply(head(x, 2), function(x) { dimnames(x) <- NULL; x }), NULL)

# cbind.xts() calls merge.xts()
do.call(cbind, d)
           c.50.0397819115463..50.2304961977954.
2007-01-02                              50.03978
2007-01-03                              50.23050
           c.50.1177772350145..50.421876002125.
2007-01-02                             50.11778
2007-01-03                             50.42188
           c.49.9504146442813..50.2304961977954.
2007-01-02                              49.95041
2007-01-03                              50.23050
           c.50.1177772350145..50.3976663383861.
2007-01-02                              50.11778
2007-01-03                              50.39767

# zoo is similar
do.call(cbind, lapply(d, as.zoo))
           structure(c(50.0397819115463, 50.2304961977954), .Dim = c(2L, 
2007-01-02                                                       50.03978
2007-01-03                                                       50.23050
           structure(c(50.1177772350145, 50.421876002125), .Dim = c(2L, 
2007-01-02                                                      50.11778
2007-01-03                                                      50.42188
           structure(c(49.9504146442813, 50.2304961977954), .Dim = c(2L, 
2007-01-02                                                       49.95041
2007-01-03                                                       50.23050
           structure(c(50.1177772350145, 50.3976663383861), .Dim = c(2L, 
2007-01-02                                                       50.11778
2007-01-03                                                       50.39767

# matrix is a little nicer
do.call(cbind, lapply(d, as.matrix))
             X[[i]]   X[[i]]   X[[i]]   X[[i]]
2007-01-02 50.03978 50.11778 49.95041 50.11778
2007-01-03 50.23050 50.42188 50.23050 50.39767
@joshuaulrich joshuaulrich added the enhancement Enhancement to existing feature label Jun 17, 2018
@joshuaulrich joshuaulrich mentioned this issue Aug 11, 2018
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joshuaulrich added a commit that referenced this issue Apr 19, 2019
@joshuaulrich
Only call as.character(dots) if necessary
d2ab0f7 
We called as.character(dots) for all objects passed to merge(), even
if we had symbol names. This was incredibly expensive for large
objects.

Now we only call as.character() on the subset of dots that do not have
symbol names. This means we will often not call as.character() at all.

See #248.
@joshuaulrich joshuaulrich self-assigned this Apr 19, 2019
@joshuaulrich joshuaulrich added this to the 0.11-2 milestone Jul 4, 2019
@joshuaulrich joshuaulrich mentioned this issue Nov 3, 2022
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