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Adding :default => true to boolean in existing Rails column
...dding a default boolean value to an existing column. So I tried the change_column suggestion but I mustn't be doing it right.
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What are POD types in C++?
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In C++11, you can do std::is_pod<MyType>() to tell whether MyType is POD.
– allyourcode
Mar 31 '14 at 21:24
7
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Django Model - Case-insensitive Query / Filtering
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I solved it like this:
MyClass.objects.filter(name__iexact=my_parameter)
There is even a way to use it for substring search:
MyClass.objects.filter(name__icontains=my_parameter)
There's a link to the documentation.
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Read url to string in few lines of java code
... Scanner(new URL(requestURL).openStream(),
StandardCharsets.UTF_8.toString()))
{
scanner.useDelimiter("\\A");
return scanner.hasNext() ? scanner.next() : "";
}
}
share
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How much is the overhead of smart pointers compared to normal pointers in C++?
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std::unique_ptr has memory overhead only if you provide it with some non-trivial deleter.
std::shared_ptr always has memory overhead for reference counter, though it is very small.
std::unique_ptr has time overhead only during constru...
Is git's semi-secret empty tree object reliable, and why is there not a symbolic name for it?
...n SHA?": it is SHA-2, since Git 2.19 (Q3 2018)
With Git 2.25 (Q1 2020), tests are preparing for a SHA-2 transition, and is involving the empty tree.
See commit fa26d5e, commit cf02be8, commit 38ee26b, commit 37ab8eb, commit 0370b35, commit 0253e12, commit 45e2ef2, commit 79b0edc, commit 840624f,...
Exact difference between CharSequence and String in java [duplicate]
...e equals, == and they are both a String and a CharSequence.
I suggest you test this code, showing in action what I just wrote:
public static void main(String[] args) {
CharSequence obj = "hello";
String str = "hello";
System.out.println("Type of obj: " + obj.getClass().getSimpleName())...
Summarizing multiple columns with dplyr? [duplicate]
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Need test on the large dataset.
– Artem Klevtsov
Mar 1 '16 at 19:21
1
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How do I concatenate two lists in Python?
...>>> l1 = [1, 2, 3]
>>> l2 = [4, 5, 6]
>>> joined_list = [*l1, *l2] # unpack both iterables in a list literal
>>> print(joined_list)
[1, 2, 3, 4, 5, 6]
This functionality was defined for Python 3.5 it hasn't been backported to previous versions in the 3.x family...
When should you use constexpr capability in C++11?
...lues over and over?
int func (int n) {
static std::map<int, int> _cached;
if (_cached.find (n) == _cached.end ())
_cached[n] = n > 0 ? n + func (n-1) : n;
return _cached[n];
}
The result
By introducing your silly optimization, you just broke every usage of your function th...