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How do I provide custom cast support for my class?
...ou want users to have to cast it or whether you want it to happen automagically. Generally, one direction will always work, that's where you use implicit, and the other direction can sometimes fail, that's where you use explicit.
The syntax is like this:
public static implicit operator dbInt64(Byt...
How to copy a row and insert in same table with a autoincrement field in MySQL?
....)
select c1, c2, ...
from your_table
where id = 1
where c1, c2, ... are all the columns except id. If you want to explicitly insert with an id of 2 then include that in your INSERT column list and your SELECT:
insert into your_table (id, c1, c2, ...)
select 2, c1, c2, ...
from your_table
where i...
How can I wait for a thread to finish with .NET?
I've never really used threading before in C# where I need to have two threads, as well as the main UI thread. Basically, I have the following.
...
How does BLAS get such extreme performance?
...e optimization. This boost significantly exceeds the second boost from parallelism and other hardware optimizations.
By the way, most (or even all) of the high performance BLAS implementations are NOT implemented in Fortran. ATLAS is implemented in C. GotoBLAS/OpenBLAS is implemented in C and i...
How do I test a camera in the iPhone simulator?
...n send it through the pipelined to be treated like a normal photo. Essentially providing the feel of a very fast camera.
CGSize sz = UIDeviceOrientationIsPortrait([[UIDevice currentDevice] orientation]) ? CGSizeMake(2448, 3264) : CGSizeMake(3264, 2448);
UIGraphicsBeginImageContextWithOptions(sz, Y...
AWS S3: how do I see how much disk space is using
...
Yippe - an update to AWS CLI allows you to recursively ls through buckets...
aws s3 ls s3://<bucketname> --recursive | grep -v -E "(Bucket: |Prefix: |LastWriteTime|^$|--)" | awk 'BEGIN {total=0}{total+=$3}END{print total/1024/1024" MB"}'
...
Get Image size WITHOUT loading image into memory
...
As the comments allude, PIL does not load the image into memory when calling .open. Looking at the docs of PIL 1.1.7, the docstring for .open says:
def open(fp, mode="r"):
"Open an image file, without loading the raster data"
There ar...
What does the “expand” option do in grunt-contrib-copy? The examples all use it but the docs say not
...n API:
Set expand to true to enable the following options:
cwd All src matches are relative to (but don't include) this path.
src Pattern(s) to match, relative to the cwd.
dest Destination path prefix.
ext Replace any existing extension with this value in generated dest paths.
ex...
Which SQL query is faster? Filter on Join criteria or Where clause?
...
Performance-wise, they are the same (and produce the same plans)
Logically, you should make the operation that still has sense if you replace INNER JOIN with a LEFT JOIN.
In your very case this will look like this:
SELECT *
FROM TableA a
LEFT JOIN
TableXRef x
ON x.TableAID = ...
Python extract pattern matches
...h a standard python REPL, the last result is stored in a special variable called _. It isn't valid outside anywhere else.
– UltraInstinct
Mar 13 '19 at 2:25
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