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What is the Java string pool and how is “s” different from new String(“s”)? [duplicate]
... a reference to an instance of class String, and is derived from a CONSTANT_String_info structure (§4.4.3) in the binary representation of a class or interface. The CONSTANT_String_info structure gives the sequence of Unicode code points constituting the string literal.
The Java programming la...
How to replace NaN values by Zeroes in a column of a Pandas Dataframe?
...ange any values (as of pandas 0.15):
idx = pd.IndexSlice
df.loc[idx[:,mask_1],idx[mask_2,:]].fillna(value=0,inplace=True)
The "problem" is that the chaining breaks the fillna ability to update the original dataframe. I put "problem" in quotes because there are good reasons for the design decision...
Ways to implement data versioning in MongoDB
...nt contain a dictionary of time-stamped diffs. Something like this:
{
_id : "id of address book record",
changes : {
1234567 : { "city" : "Omaha", "state" : "Nebraska" },
1234568 : { "city" : "Kansas City", "state" : "Missouri" }
}
}
To make...
Getting the class name from a static method in Java
...ass<?>> myself = StackWalker.getInstance(StackWalker.Option.RETAIN_CLASS_REFERENCE) .walk(s -> s.map(StackWalker.StackFrame::getDeclaringClass) .findFirst());, but of course, that’s connected to the fact that it will be much more powerful.
– Holger
...
Swift - Convert to absolute value
...alue.magnitude) // prints: 5
#2. Get absolute value of an Int from abs(_:) method
Swift has a global numeric function called abs(_:) method. abs(_:) has the following declaration:
func abs<T>(_ x: T) -> T where T : Comparable, T : SignedNumeric
Returns the absolute value of the g...
Redirecting Output from within Batch file
...olution offered by @dbenham. So for example, this:
@echo off
> filename_prefix-%DATE:~-4%-%DATE:~4,2%-%DATE:~7,2%_%time:~0,2%%time:~3,2%%time:~6,2%.log (
echo Your Name Here
echo Beginning Date/Time: %DATE:~-4%-%DATE:~4,2%-%DATE:~7,2%_%time:~0,2%%time:~3,2%%time:~6,2%.log
REM do some stuff here
...
How to easily resize/optimize an image size with iOS?
...r(portrait) on right side plz give me solution
– Nag_iphone
Oct 24 '11 at 11:17
1
...
How to manually expand a special variable (ex: ~ tilde) in bash
...
+1 -- I was needing to expand ~$some_other_user and eval works fine when $HOME will not work because I don't need the current user home.
– olivecoder
Sep 10 '13 at 11:30
...
How to clear MemoryCache?
...ntHandler<SignaledChangeEventArgs> Signaled;
private string _name;
private string _uniqueId = Guid.NewGuid().ToString("N", CultureInfo.InvariantCulture);
public override string UniqueId
{
get { return _uniqueId; }
}
public Signaled...
Count number of records returned by group by
...rGroup,
COUNT(*) OVER () AS TotalRecords
from temptable
group by column_1, column_2, column_3, column_4
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