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SQL Server - stop or break execution of a SQL script
...hi
Msg 2745, Level 16, State 2, Line 1
Process ID 51 has raised user error 50000, severity 20. SQL Server is terminating this process.
Msg 50000, Level 20, State 1, Line 1
Oh no a fatal error
Msg 0, Level 20, State 0, Line 0
A severe error occurred on the current command. The results, if any, shoul...
What's the fastest way to merge/join data.frames in R?
...w data.table and dplyr :)
Larger data set:
N <- 1e8
g1 <- sample(1:50000, N, replace = TRUE)
g2<- sample(1:50000, N, replace = TRUE)
d <- data.frame(x=sample(N,N), y=rnorm(N), g1, g2)
Took around 10-13GB of ram just to hold the data before running the benchmark.
Results:
...
How to get last N records with activerecord?
...t(5)
because:
Something.last(5).class
=> Array
so:
Something.last(50000).count
will likely blow up your memory or take forever.
Good approach:
Something.limit(5).order('id desc')
because:
Something.limit(5).order('id desc').class
=> Image::ActiveRecord_Relation
Something.limit(5)...
Count number of occurences for each unique value
...
This works for me. Take your vector v
length(summary(as.factor(v),maxsum=50000))
Comment: set maxsum to be large enough to capture the number of unique values
or with the magrittr package
v %>% as.factor %>% summary(maxsum=50000) %>% length
...
Very large matrices using Python and NumPy
...begins to struggle with anything much larger (trying to create a matrix of 50000 x 50000 fails). Obviously, this is because of the massive memory requirements.
...
Convert timestamp in milliseconds to string formatted time in Java
...
Division is not associative: 50000 / (1000 * 60) = 0.8333333333 while 50000 / 1000 * 60= 3000.
– farnett
Feb 16 '15 at 22:05
3
...
Counting the number of True Booleans in a Python List
... my results:
>>> a = [bool(random.getrandbits(1)) for x in range(50000)]
>>> len(a)
50000
>>> a.count(False)
24884
>>> a.count(True)
25116
>>> def count_it(a):
... curr = time.time()
... counting = a.count(True)
... print("Count it = " + str(time.t...
GROUP_CONCAT ORDER BY
...
You can use ORDER BY inside the GROUP_CONCAT function in this way:
SELECT li.client_id, group_concat(li.percentage ORDER BY li.views ASC) AS views,
group_concat(li.percentage ORDER BY li.percentage ASC)
FROM li GROUP BY client_id
...
Redis strings vs Redis hashes to represent JSON: efficiency?
...
> redis.pipelined{ 10000.times{ |i| redis.me_set( "t:#{i}", txt[rand(50000), 63] ) } }; :done
=> :done
> ap redis.info(:memory)
{
"used_memory" => "1251944",
**"used_memory_human" => "1.19M"**, # ~ 72b per key/value
.....
}
> redis.fl...
String concatenation: concat() vs “+” operator
....
Firstly, there's a slight difference in semantics. If a is null, then a.concat(b) throws a NullPointerException but a+=b will treat the original value of a as if it were null. Furthermore, the concat() method only accepts String values while the + operator will silently convert the argument to a ...