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How can I delay a method call for 1 second?
...ation/…:
– harms
May 28 '09 at 13:06
Is there any way to something with the return value of the method that gets cal...
How to redirect 404 errors to a page in ExpressJS?
...low,
// this means that Express will attempt
// to match & call routes _before_ continuing
// on, at which point we assume it's a 404 because
// no route has handled the request.
app.use(app.router);
// Since this is the last non-error-handling
// middleware use()d, we assume 404, as nothing e...
Include all existing fields and add new fields to document
...s the new fields.
db.collection.aggregate([
{ "$addFields": { "custom_field": "$obj.obj_field1" } }
])
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How to track down a “double free or corruption” error
...
If you're using glibc, you can set the MALLOC_CHECK_ environment variable to 2, this will cause glibc to use an error tolerant version of malloc, which will cause your program to abort at the point where the double free is done.
You can set this from gdb by using the s...
How does the main() method work in C?
... be handled. */
extern int main(int argc, char **argv, char **envp);
void __start(void)
{
/* This is the real startup function for the executable.
It performs a bunch of library initialization. */
/* ... */
/* And then: */
exit(main(argc_from_somewhere, argv_from_somewhere, envp_from...
How to use if - else structure in a batch file?
...at least was) DOS!
@echo off
set one=1
set two=2
REM Example 1
IF %one%_%two%==1_1 (
echo Example 1 fails
) ELSE IF %one%_%two%==1_2 (
echo Example 1 works correctly
) ELSE (
echo Example 1 fails
)
REM Example 2
set test1result=0
set test2result=0
if %one%==1 if %two%==1 set test1re...
Why does modern Perl avoid UTF-8 by default?
...???????????????????????????????????????????????????????????
Set your PERL_UNICODE envariable to AS. This makes all Perl scripts decode @ARGV as UTF‑8 strings, and sets the encoding of all three of stdin, stdout, and stderr to UTF‑8. Both these are global effects, not lexical ones.
At the top o...
Cleaner way to update nested structures
...ss, and an address in a person:
val addressZipCodeLens = Lens(
get = (_: Address).zipCode,
set = (addr: Address, zipCode: Int) => addr.copy(zipCode = zipCode))
val personAddressLens = Lens(
get = (_: Person).address,
set = (p: Person, addr: Address) => p.copy(address = addr)...
Convert a row of a data frame to vector
...u have to be careful if your row contains a factor. Here is an example:
df_1 = data.frame(V1 = factor(11:15),
V2 = 21:25)
df_1[1,] %>% as.numeric() # you expect 11 21 but it returns
[1] 1 21
Here is another example (by default data.frame() converts characters to factors)
d...
how to return index of a sorted list? [duplicate]
...ray([2,3,1,4,5])
>>> vals
array([2, 3, 1, 4, 5])
>>> sort_index = numpy.argsort(vals)
>>> sort_index
array([2, 0, 1, 3, 4])
If not available, taken from this question, this is the fastest method:
>>> vals = [2,3,1,4,5]
>>> sorted(range(len(vals)), key=...