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Secret copy to clipboard JavaScript function in Chrome and Firefox?
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63
I believe these are predefined Firebug console functions - at least that seems to be the case fo...
What is the difference between allprojects and subprojects
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123
In a multi-project gradle build, you have a rootProject and the subprojects. The combination of ...
Deprecation warning when using has_many :through :uniq in Rails 4
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238
The uniq option needs to be moved into a scope block. Note that the scope block needs to be the...
ng-options with simple array init
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306
You actually had it correct in your third attempt.
<select ng-model="myselect" ng-options...
Postgres: How to do Composite keys?
... tag1 VARCHAR(20),
tag2 VARCHAR(20),
tag3 VARCHAR(20),
PRIMARY KEY(question_id, tag_id)
);
NOTICE: CREATE TABLE will create implicit sequence "tags_tag_id_seq" for serial column "tags.tag_id"
NOTICE: CREATE TABLE / PRIMARY KEY will creat...
Is there any git hook for pull?
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edited Jul 26 '17 at 20:32
answered Nov 15 '10 at 14:46
C...
What does 'stale file handle' in Linux mean?
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83
When the directory is deleted, the inode for that directory (and the inodes for its contents) ar...
How to preserve line breaks when storing a command output to a variable in bash?
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edited Feb 28 '14 at 17:31
answered Feb 28 '14 at 17:25
j...
Merge git repo into branch of another repo
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3 Answers
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Active
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dplyr summarise: Equivalent of “.drop=FALSE” to keep groups with zero length in output
....drop argument that does just what you asked for:
df = data.frame(a=rep(1:3,4), b=rep(1:2,6))
df$b = factor(df$b, levels=1:3)
df %>%
group_by(b, .drop=FALSE) %>%
summarise(count_a=length(a))
#> # A tibble: 3 x 2
#> b count_a
#> <fct> <int>
#> 1 1 ...