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Test if a variable is a list or tuple
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Go ahead and use isinstance if you need it. It is somewhat evil, as it excludes custom sequences, iterators, and other things that you might actually need. However, sometimes you need to behave differently if someone, for instance, passes a string. My preference...
structure vs class in swift language
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Here's an example with a class. Note how when the name is changed, the instance referenced by both variables is updated. Bob is now Sue, everywhere that Bob was ever referenced.
class SomeClass {
var name: String
init(name: String) {
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Python SQL query string formatting
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my application I'd like to log to file all the sql query strings, and it is
important that the string is properly formated.
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What's a concise way to check that environment variables are set in a Unix shell script?
..."}
: ${DEST:?"Need to set DEST non-empty"}
Or, better (see section on 'Position of double quotes' below):
: "${STATE?Need to set STATE}"
: "${DEST:?Need to set DEST non-empty}"
The first variant (using just ?) requires STATE to be set, but STATE="" (an empty string) is OK — not exactly what you ...
Disable Automatic Reference Counting for Some Files
...The ARC converter doesn't work here, because some frameworks, such as JSONKit, cannot be converted to ARC by using the converter.
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Overflow-x:hidden doesn't prevent content from overflowing in mobile browsers
I have a website here .
16 Answers
16
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boost::flat_map and its performance compared to map and unordered_map
It is common knowledge in programming that memory locality improves performance a lot due to cache hits. I recently found out about boost::flat_map which is a vector based implementation of a map. It doesn't seem to be nearly as popular as your typical map / unordered_map so I haven't been able ...
How can I ensure that a division of integers is always rounded up?
... blog in January 2013. Thanks for the great question!
Getting integer arithmetic correct is hard. As has been demonstrated amply thus far, the moment you try to do a "clever" trick, odds are good that you've made a mistake. And when a flaw is found, changing the code to fix the flaw without cons...
How do JavaScript closures work?
How would you explain JavaScript closures to someone with a knowledge of the concepts they consist of (for example functions, variables and the like), but does not understand closures themselves?
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How can I safely create a nested directory?
... is the most elegant way to check if the directory a file is going to be written to exists, and if not, create the directory using Python? Here is what I tried:
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