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Conveniently Declaring Compile-Time Strings in C++
...
I haven't seen anything to match the elegance of Scott Schurr's str_const presented at C++ Now 2012. It does require constexpr though.
Here's how you can use it, and what it can do:
int
main()
{
constexpr str_const my_string = "Hello, world!";
static_assert(my_string.size() == 13,...
What is in your Mathematica tool bag? [closed]
...and Sow which mimics/extends the behavior of GatherBy:
SelectEquivalents[x_List,f_:Identity, g_:Identity, h_:(#2&)]:=
Reap[Sow[g[#],{f[#]}]&/@x, _, h][[2]];
This allows me to group lists by any criteria and transform them in the process. The way it works is that a criteria function (f...
Does reading an entire file leave the file handle open?
...file is closed, is this pattern:
with open('Path/to/file', 'r') as content_file:
content = content_file.read()
which will always close the file immediately after the block ends; even if an exception occurs.
Edit: To put a finer point on it:
Other than file.__exit__(), which is "automatical...
How to printf uint64_t? Fails with: “spurious trailing ‘%’ in format”
I wrote a very simple test code of printf uint64_t:
3 Answers
3
...
Convert objective-c typedef to its string equivalent
... XML,
Atom,
RSS
} FormatType;
extern NSString * const FormatType_toString[];
// In a source file
// initialize arrays with explicit indices to make sure
// the string match the enums properly
NSString * const FormatType_toString[] = {
[JSON] = @"JSON",
[XML] = @"XML",
[Atom]...
How to find out if an installed Eclipse is 32 or 64 bit version?
...e the line with text:
plugins/org.eclipse.equinox.launcher.win32.win32.x86_64_1.0.200.v20090519
then it is 64 bit.
If it would be plugins/org.eclipse.equinox.launcher.win32.win32.x86_32_1.0.200.v20090519 then it is 32 bit.
...
Why doesn't list have safe “get” method like dictionary?
...f your list).
Of course, you can easily implement this yourself:
def safe_list_get (l, idx, default):
try:
return l[idx]
except IndexError:
return default
You could even monkeypatch it onto the __builtins__.list constructor in __main__, but that would be a less pervasive change since...
Why dict.get(key) instead of dict[key]?
...ide a default value if the key is missing:
dictionary.get("bogus", default_value)
returns default_value (whatever you choose it to be), whereas
dictionary["bogus"]
would raise a KeyError.
If omitted, default_value is None, such that
dictionary.get("bogus") # <-- No default specified --...
foreach vs someList.ForEach(){}
...lException(ExceptionArgument.match);
}
for (int i = 0; i < this._size; i++)
{
action(this._items[i]);
}
}
Similarly, the MoveNext in Enumerator which is what is used by foreach is this:
public bool MoveNext()
{
if (this.version != this.list._version)
{
T...
In where shall I use isset() and !empty()
.....) contains some non-empty data.
To answer question 1 :
$str = '';
var_dump(isset($str));
gives
boolean true
Because the variable $str exists.
And question 2 :
You should use isset to determine whether a variable exists ; for instance, if you are getting some data as an array, you migh...