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Nesting await in Parallel.ForEach
...ix” that by blocking the ForEach() threads, but that defeats the whole point of async-await.
What you could do is to use TPL Dataflow instead of Parallel.ForEach(), which supports asynchronous Tasks well.
Specifically, your code could be written using a TransformBlock that transforms each id int...
Is there a regular expression to detect a valid regular expression?
...n directly. (The (?1) and (?R) constructs.) The recursion would have to be converted to counting balanced groups:
^ # start of string
(?:
(?: [^?+*{}()[\]\\|]+ # literals and ^, $
| \\. # escaped charact...
Label encoding across multiple columns in scikit-learn
...
We don't need a LabelEncoder.
You can convert the columns to categoricals and then get their codes. I used a dictionary comprehension below to apply this process to every column and wrap the result back into a dataframe of the same shape with identical indices a...
Error java.lang.OutOfMemoryError: GC overhead limit exceeded
...t'll be hard to tell which one is misbehaving. Separating the applications into distinct JVMs might be the easiest solution.
– Joachim Sauer
Mar 1 '12 at 11:48
...
What is the advantage of using abstract classes instead of traits?
...ure even traits can have constructor parameters
Abstract classes are fully interoperable with Java. You can call them from Java code without any wrappers. Traits are fully interoperable only if they do not contain any implementation code
...
Check if a string matches a regex in Bash script
...is in the correct format, it is best to parse it with date and ask date to convert the string to the correct format. If both strings are identical, you have a valid format and valid date.
if [[ "$datestr" == $(date -d "$datestr" "+%Y%m%d" 2>/dev/null) ]]; then
echo "Valid date"
else
e...
The constant cannot be marked static
...tance to reference the const value).
I want to also add this important point: When you link against (reference) an assembly with a public const, that value is copied into your assembly. So if the const value in the referenced assembly changes, your assembly will still have the originally compiled-...
MySQL - Rows to Columns
...three-step process (with an optional fourth step):
select the columns of interest, i.e. y-values and x-values
extend the base table with extra columns -- one for each x-value
group and aggregate the extended table -- one group for each y-value
(optional) prettify the aggregated table
Let's apply...
How to check whether an array is empty using PHP?
...er(): If no callback is supplied, all entries of array equal to FALSE (see converting to boolean) will be removed.
If you'd like to remove all NULL, FALSE and empty strings (''), but leave zero values (0), you can use strlen as a callback, e.g.:
$is_empty = array_filter($playerlist, 'strlen') == ...
Multiple Updates in MySQL
...u can use INSERT ... ON DUPLICATE KEY UPDATE.
Using your example:
INSERT INTO table (id,Col1,Col2) VALUES (1,1,1),(2,2,3),(3,9,3),(4,10,12)
ON DUPLICATE KEY UPDATE Col1=VALUES(Col1),Col2=VALUES(Col2);
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