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Check if a string has white space
... "/" characters are sufficient.
/^\s+$/ is checking whether the string is ALL whitespace:
^ matches the start of the string.
\s+ means at least 1, possibly more, spaces.
$ matches the end of the string.
Try replacing the regex with /\s/ (and no quotes)
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How can I add a help method to a shell script?
... into a shell script? I would like to display a help message when a user calls myscript.sh -h .
6 Answers
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Which parts of Real World Haskell are now obsolete or considered bad practice?
...move return from Monad, so the Monad instance in Real World Haskell will really be out of sync with the real world.
That being said, it's still a useful resource for general guidelines. But keep in mind that many libraries changed since its release.
Something you can read along while reading RWH i...
'IF' in 'SELECT' statement - choose output value based on column values
...tp://dev.mysql.com/doc/refman/5.0/en/control-flow-functions.html.
Additionally, you could handle when the condition is null. In the case of a null amount:
SELECT id,
IF(type = 'P', IFNULL(amount,0), IFNULL(amount,0) * -1) as amount
FROM report
The part IFNULL(amount,0) means when amount ...
Does Android keep the .apk files? if so where?
After android installs an application from the Marketplace, does it keep the .apk file?
19 Answers
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In Python, how do you convert a `datetime` object to seconds?
...datetime(1970,1,1)).total_seconds()
1256083200.0
The starting date is usually specified in UTC, so for proper results the datetime you feed into this formula should be in UTC as well. If your datetime isn't in UTC already, you'll need to convert it before you use it, or attach a tzinfo class that ...
Php multiple delimiters in explode
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You can take the first string, replace all the @ with vs using str_replace, then explode on vs or vice versa.
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LINQ .Any VS .Exists - What's the difference?
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I later made a post in another thread where I listed all the Linq "equivalents" of the .NET 2 List<> instance methods.
– Jeppe Stig Nielsen
Dec 1 '15 at 8:44
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How to choose the right bean scope?
...s as long as you're interacting with the same JSF view by postbacks which call action methods returning null/void without any navigation/redirect. A @FlowScoped bean lives as long as you're navigating through the specified collection of views registered in the flow configuration file. A @SessionScop...
JPA: How to have one-to-many relation of the same Entity type
...em.persist(daughter);
em.getTransaction().commit();
}
In this case, all three entity instances must be persisted before transaction commit. If I fail to persist one of the entities in the graph of parent-child relationships, then an exception is thrown on commit(). On Eclipselink, this is a...