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How to select the rows with maximum values in each group with dplyr? [duplicate]
...imum value (in this example, it will take one of the corresponding rows randomly)
library(dplyr)
df %>% group_by(A, B) %>%
mutate(the_rank = rank(-value, ties.method = "random")) %>%
filter(the_rank == 1) %>% select(-the_rank)
...
javascript check for not null
...
this will do the trick for you
if (!!val) {
alert("this is not null")
} else {
alert("this is null")
}
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What is the purpose of Order By 1 in SQL select statement?
...ve noticed that there are several views with an order by 1 clause. What does this accomplish?
8 Answers
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how to break the _.each function in underscore.js
...() method, but can't find the solution. jQuery .each() can break if you do return false .
11 Answers
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How to fix PCH error?
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This is often a caching problem. Usually it can be resolved by holding down the Option key and choosing Product > Clean Build Folder...
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How can I use Spring Security without sessions?
... on Amazon EC2 and use Amazon's Elastic Load Balancers. Unfortunately, ELB does not support sticky sessions, so I need to ensure my application works properly without sessions.
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How to display unique records from a has_many through relationship?
..._many :products, :through => :orders, :uniq => true
From the Rails documentation:
:uniq
If true, duplicates will be omitted from the collection. Useful in conjunction with :through.
UPDATE FOR RAILS 4:
In Rails 4, has_many :products, :through => :orders, :uniq => true is de...
Using awk to remove the Byte-order mark
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It seems that the dot in the middle of the sub statement is too much (at least, my awk complains about it). Beside this it's exactly what I searched, thanks!
– Boldewyn
Jul 1 '09 at 12:21
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Set a persistent environment variable from cmd.exe
I have to set environment variables on different windows machines, but I don't want to be bothered changing them manually by getting on the properties screen of "My Computer"
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Override configured user for a single git commit
... tracks both.
To set what name to use for just this repository, you could do:
git config user.name "Your Name"
git config user.email "Your email"
Notice the absence of the --global option. This will set the configuration in this repository only.
Alternatively, you can do this for only a sing...