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How to wait for several Futures?
...ave several futures and need to wait until either any of them fails or all of them succeed.
8 Answers
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Include all existing fields and add new fields to document
...t aggregation stage where I can instruct it to add a new field and include all existing fields, without having to list all the existing fields.
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Run certain code every n seconds [duplicate]
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This seems not to resolve the question at all... it does not repeat every second.
– Yan King Yin
Jul 5 '13 at 15:28
9
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What is time_t ultimately a typedef to?
...IX-compliant systems implement the time_t type as a signed
integer (typically 32 or 64 bits wide)
which represents the number of seconds
since the start of the Unix epoch:
midnight UTC of January 1, 1970 (not
counting leap seconds). Some systems
correctly handle negative time values,
w...
Is there a performance difference between a for loop and a for-each loop?
... iterator or index variable
completely. The resulting idiom
applies equally to collections and
arrays:
// The preferred idiom for iterating over collections and arrays
for (Element e : elements) {
doSomething(e);
}
When you see the colon (:), read it as
“in.” Thus, the loop ab...
How do arrays in C# partially implement IList?
...ional, zero-based arrays, as far as the language is concerned, the array really does implement IList<T> too. Section 12.1.2 of the C# specification says so. So whatever the underlying implementation does, the language has to behave as if the type of T[] implements IList<T> as with any ot...
Batch File; List files in directory, only filenames?
...s is probably a very simple question, but I'm having trouble with it. Basically, I am trying to write a Batch File and I need it to list all the files in a certain directory. The dir command will do this, but it also gives a bunch of other information; I want it to list ONLY the file names and e...
Can comments be used in JSON?
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No.
The JSON should all be data, and if you include a comment, then it will be data too.
You could have a designated data element called "_comment" (or something) that would be ignored by apps that use the JSON data.
You would probably be bett...
SQL Server - Create a copy of a database table and place it in the same database?
...a new table with the same column structure (just like he said) and inserts all data into the new table for you.
– user5855178
Apr 5 '17 at 14:14
1
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cannot convert data (type interface {}) to type string: need type assertion
...]i to its value type, we have to do it individually:
// var items []i
for _, item := range items {
value, ok := item.(T)
dosomethingWith(value)
}
Performance
As for performance, it can be slower than direct access to the actual value as show in this stackoverflow answer.
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