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Grouping functions (tapply, by, aggregate) and the *apply family
...ss 2nd and 3rd dimension
apply(M, 1, sum)
# Result is one-dimensional
[1] 120 128 136 144
# Apply sum across each M[*, *, ] - i.e Sum across 3rd dimension
apply(M, c(1,2), sum)
# Result is two-dimensional
[,1] [,2] [,3] [,4]
[1,] 18 26 34 42
[2,] 20 28 36 44
[3,] 22 30 38...
Implicit type conversion rules in C++ operators
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edited Jun 20 at 9:12
Community♦
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answered Apr 6 '11 at 7:49
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Javascript infamous Loop issue? [duplicate]
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edited Jun 20 at 9:12
Community♦
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answered Sep 20 '09 at 13:43
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Retrieve a single file from a repository
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answered Aug 20 '13 at 9:23
Yisrael DovYisrael Dov
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Python: Checking if a 'Dictionary' is empty doesn't seem to work
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edited Apr 20 '14 at 1:37
answered Apr 20 '14 at 1:31
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Computed / calculated / virtual / derived columns in PostgreSQL
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answered Dec 13 '15 at 20:06
ElmerElmer
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How to equalize the scales of x-axis and y-axis in Python matplotlib?
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edited Apr 30 '19 at 10:20
Georgy
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answered Dec...
What is the difference between assert, expect and should in Chai?
...ue");
– user5325596
Mar 29 '16 at 9:20
I cannot get any custom message to appear with expect, using the latest versio...
PostgreSQL: How to make “case-insensitive” query
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Also specify varchar_pattern_ops if you want the index to work with LIKE 'xxx%' query, i.e. CREATE INDEX ix_groups_name ON groups (lower(na...
How to reuse an ostringstream?
...; ends;
– user34537
Jun 6 '11 at 16:20
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