You can check the value of $- to see the current options; if it contains an x, it was set. You can check like so: old_setting=${-//[^x]/} … if [[ -n “$old_setting” ]]; then set -x; else set +x; fi In case it’s not familiar to you: the ${} above is a Bash Substring Replacement, which … Read more
Your understanding is correct: the only difference is that ifilter returns an iterator, while using filter is like calling: list(ifilter(…)) You may also be interested in what PEP 289 says about filter and ifilter: List comprehensions greatly reduced the need for filter() and map(). Likewise, generator expressions are expected to minimize the need for itertools.ifilter() … Read more
EDIT As of groovy 1.8.6 you can use the collate method on lists def origList = [1, 2, 3, 4, 5, 6, 7, 8, 9] assert [[1, 2, 3, 4], [5, 6, 7, 8], [9]] == origList.collate(4) Another method using inject and metaClasses List.metaClass.partition = { size -> def rslt = delegate.inject( [ [] ] … Read more
There is no easy way to do this like with MySQL, but there are some options: One: Some wrapper-libraries have something like this built-in. But to find a wrapper library you would probably first need to identify the target language. Perl DBI? Python? C++? Two: I would not (in any way) recommend the following for … Read more
Objects in Python can have attributes — data attributes and functions to work with those (methods). Actually, every object has built-in attributes (try dir(None), dir(True), dir(…), dir(dir) in Python console). For example you have an object person, that has several attributes: name, gender, etc. You access these attributes (be it methods or data objects) usually … Read more
It stands for “ordinal”. The earliest use of ord that I remember was in Pascal. There, ord() returned the ordinal value of its argument. For characters this was defined as the ASCII code. The same convention was also used in Modula-2. Later, Python (as well as PHP, some dialects of SQL etc) followed this convention, … Read more
Check this out. https://docs.python.org/3/howto/descriptor.html#class-methods You can also take a look at the source code for class and static method objects, in funcobject.c: http://hg.python.org/cpython/file/69b416cd1727/Objects/funcobject.c Class method object definition starts on line 694, while static method object definition starts on line 852. (I do find it kind of funny that they have items titled “method” in funcobject.c … Read more
There’s no special reason, to my knowledge – I’d guess that the reason is that for so many applications the highly-tuned dict and set implementations (which are hash tables) work well. They’re good enough in most cases. There are definitely situations where you need the performance characteristics of balanced binary search trees (like ordered traversal … Read more