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SQL - find records from one table which don't exist in another
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An advantage of this approach (vs. LEFT OUTER JOIN by WOPR) is that it avoids returning multiple rows per row of Call, if there are multiple matching rows in Phone_book. That is, if there is a 1:N relationship between your two tables.
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Is there a way to make GHC provide the type class constraints of typed holes?
...ng out-of-scope types
(use -fprint-potential-instances to see them all)
• In the expression: show _
In an equation for ‘it’: it = show _
<interactive>:3:6: error:
• Found hole: _ :: a0
Where: ‘a0’ is an ambiguous type variable
• In the first argum...
How to parse/read a YAML file into a Python object? [duplicate]
...ame: Node 2
branch2-1:
name: Node 2-1
And you've installed PyYAML like this:
pip install PyYAML
And the Python code looks like this:
import yaml
with open('tree.yaml') as f:
# use safe_load instead load
dataMap = yaml.safe_load(f)
The variable dataMap now contains...
How to start two threads at “exactly” the same time
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// Now if we block on the gate from the main thread, it will open
// and all threads will start to do stuff!
gate.await();
System.out.println("all threads started");
This doesn't have to be a CyclicBarrier, you could also use a CountDownLatch or even a lock.
This still can't make sure that ...
How to reverse a string in Go?
...size of the input in bytes. It does not correspond to its length. - Not all utf8's runes are of the same size. It can be either 1, 2, 4, or 8. - You should use unicode/ut8 package's method RuneCountInString to get the length of the rune.
– Anvesh Checka
M...
Linux - Replacing spaces in the file names
...umber of files in a folder, and I want to replace every space character in all file names with underscores. How can I achieve this?
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Spinlock versus Semaphore
...ck (or, the other way around, a lock is a special case of a semaphore). Usually, but not necessarily, spinlocks are only valid within one process whereas semaphores can be used to synchronize between different processes, too.
A lock works for mutual exclusion, that is one thread at a time can acqui...
How does Apple know you are using private API?
...since I do not work in the Apple review team.
1. otool -L
This will list all libraries the app has linked to. Something clearly you should not use, like IOKit and WebKit can be detected by this.
2. nm -u
This will list all linked symbols. This can detect
Undocumented C functions such as _UIIma...
In Python, how do I indicate I'm overriding a method?
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Based on this and fwc:s answer I created a pip installable package https://github.com/mkorpela/overrides
From time to time I end up here looking at this question.
Mainly this happens after (again) seeing the same bug in our code base: Someone has forgotten some "interface" i...
Redirect all to index.php using htaccess
...le PHP-based MVC-ish framework. I want this framework to be able to be installed in any directory.
7 Answers
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