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Or versus OrElse
... the right operand won't even be evaluated (this is useful in cases like:
string a;
//...
if (a is null) or (a = "Hi") //...
to avoid a NullReferenceException throw by the right-hand operand.
I'm sincerely astonished that this (lazy evaluation) isn't the default behaviour of or and and as it is ...
Scala best way of turning a Collection into a Map-by-key?
...sult into a variable argument.
scala> val list = List("this", "maps", "string", "to", "length") map {s => (s, s.length)}
list: List[(java.lang.String, Int)] = List((this,4), (maps,4), (string,6), (to,2), (length,6))
scala> val list = List("this", "is", "a", "bunch", "of", "strings")
list:...
How to replace a hash key with another key
...
If all the keys are strings and all of them have the underscore prefix, then you can patch up the hash in place with this:
h.keys.each { |k| h[k[1, k.length - 1]] = h[k]; h.delete(k) }
The k[1, k.length - 1] bit grabs all of k except the firs...
Why do people say there is modulo bias when using a random number generator?
... particularly hard to avoid in computing, where numbers are represented as strings of bits: 0s and 1s. Finding truly random sources of randomness is also extremely difficult, but is beyond the scope of this discussion. For the remainder of this answer, assume that there exists an unlimited source of...
Does reading an entire file leave the file handle open?
...
Instead of retrieving the file content as a single string,
it can be handy to store the content as a list of all lines the file comprises:
with open('Path/to/file', 'r') as content_file:
content_list = content_file.read().strip().split("\n")
As can be seen, one needs t...
How to list the contents of a package using YUM?
...s taken with spacing):
Loaded plugins: fastestmirror
base | 3.6 kB 00:00
extras | 3.4 kB 00:00
updates | 3.4 kB 00:00
(1/4): extras/7/x86_64/primary_db | 166 kB 00:00
(2/4): base/7/x86_64/group_gz | 155 kB 00:00
(3/4): updates/7/x86_64/primary_db | 9.1 MB 00:04
(4/4): base/7/x86_64/primary_db...
Comparing two dictionaries and checking how many (key, value) pairs are equal
...th possibly different attribute values as in the example). However, if an "extra" attribute is present is one of the dicts, json.dumps() fails with
TypeError: Object of type PrettyOrderedSet is not JSON serializable
Solution: use diff.to_json() and json.loads() / json.dumps() to pretty-print:
im...
How to split strings across multiple lines in CMake?
... But with CMake I get the problem that I do not know how to split a simple string into multiple lines to avoid one huge line. Consider this basic code:
...
Is it possible to implement a Python for range loop without an iterator variable?
...'myapplication')
_ = gettext.gettext
# ...
print _('This is a translatable string.')
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When saving, how can you check if a field has changed?
...
Really perfect, and do not perform extra query. Thanks a lot !
– Stéphane
Mar 4 '13 at 10:26
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