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Does the join order matter in SQL?
Disregarding performance, will I get the same result from query A and B below? How about C and D?
4 Answers
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How can I parse a YAML file in Python
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The easiest and purest method without relying on C headers is PyYaml (documentation), which can be installed via pip install pyyaml:
#!/usr/bin/env python
import yaml
with open("example.yaml", 'r') as stream:
try:
print(yam...
Can I serve multiple clients using just Flask app.run() as standalone?
...h Apache or other web servers. But, I was thinking of running Flask as a standalone server serving multiple clients simultaneously.
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How to prune local tracking branches that do not exist on remote anymore
...es.
This line should do the trick (requires bash or zsh, won't work with standard Bourne shell):
git branch -r | awk '{print $1}' | egrep -v -f /dev/fd/0 <(git branch -vv | grep origin) | awk '{print $1}' | xargs git branch -d
This string gets the list of remote branches and passes it into egrep...
Java ArrayList copy
... l1 of size 10. I assign l1 to new list reference type l2 . Will l1 and l2 point to same ArrayList object? Or is a copy of the ArrayList object assigned to l2 ?
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Understand homebrew and keg-only dependencies
I've recently started using homebrew, and I'm a bit confused as to what happens when I brew something onto my system, but its brewed dependencies are keg-only, meaning that they are linked under /usr/local .
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redirect COPY of stdout to log file from within bash script itself
...ptured - i.e. your
# log file would not contain any error messages.
# SEE (and upvote) the answer by Adam Spiers, which keeps STDERR
# as a separate stream - I did not want to steal from him by simply
# adding his answer to mine.
exec 2>&1
echo "foo"
echo "bar" >&2
Note that this is...
Find() vs. Where().FirstOrDefault()
I often see people using Where.FirstOrDefault() to do a search and grab the first element. Why not just use Find() ? Is there an advantage to the other? I couldn't tell a difference.
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How to implement WiX installer upgrade?
...omatic upgrades. It prevents downgrades, giving a localised error message, and also prevents upgrading an already existing identical version (i.e. only lower versions are upgraded):
<MajorUpgrade
AllowDowngrades="no" DowngradeErrorMessage="!(loc.NewerVersionInstalled)"
AllowSameVersionUp...
Detect changes in the DOM
...need to create your own domChanged API - with a function or custom event - and trigger/call it everywhere you modify things.
The DOM Level-2 has Mutation event types, but older version of IE don't support it. Note that the mutation events are deprecated in the DOM3 Events spec and have a performan...