Part of question regarding out-of-range indices Slice logic automatically clips the indices to the length of the sequence. Allowing slice indices to extend past end points was done for convenience. It would be a pain to have to range check every expression and then adjust the limits manually, so Python does it for you. Consider … Read more
select sequence_owner, sequence_name from dba_sequences; DBA_SEQUENCES — all sequences that exist ALL_SEQUENCES — all sequences that you have permission to see USER_SEQUENCES — all sequences that you own Note that since you are, by definition, the owner of all the sequences returned from USER_SEQUENCES, there is no SEQUENCE_OWNER column in USER_SEQUENCES.
iter(x) will raise a TypeError if x cannot be iterated on — but that check “accepts” sets and dictionaries, though it “rejects” other non-sequences such as None and numbers. On the other hands, strings (which most applications want to consider “single items” rather than sequences) are in fact sequences (so, any test, unless specialcased for … Read more
You’re looking for seq > seq(as.Date(“2011-12-30”), as.Date(“2012-01-04″), by=”days”) [1] “2011-12-30” “2011-12-31” “2012-01-01” “2012-01-02” “2012-01-03” [6] “2012-01-04” Or, you can use : > as.Date(as.Date(“2011-12-30”):as.Date(“2012-01-04″), origin=”1970-01-01”) [1] “2011-12-30” “2011-12-31” “2012-01-01” “2012-01-02” “2012-01-03” [6] “2012-01-04″ Note that with : “Non-numeric arguments are coerced internally”. Thus, we convert back to class Date, using as.Date method for class ‘numeric’ and … Read more
At my job, we use UUID as PKs. What I can tell you from experience is DO NOT USE THEM as PKs (SQL Server by the way). It’s one of those things that when you have less than 1000 records it;s ok, but when you have millions, it’s the worst thing you can do. Why? … Read more
One difference is that conj accepts any number of arguments to insert into a collection, while cons takes just one: (conj ‘(1 2 3) 4 5 6) ; => (6 5 4 1 2 3) (cons 4 5 6 ‘(1 2 3)) ; => IllegalArgumentException due to wrong arity Another difference is in the class … Read more
You can use a generator expression: >>> l = [1, 3, 7, 2, 6, 8, 10] >>> sum(1 for i in l if i % 4 == 3) 2 or even >>> sum(i % 4 == 3 for i in l) 2 which uses the fact that True == 1 and False == 0. Alternatively, … Read more
You can add a column to your data using various techniques. The quotes below come from the “Details” section of the relevant help text, [[.data.frame. Data frames can be indexed in several modes. When [ and [[ are used with a single vector index (x[i] or x[[i]]), they index the data frame as if it … Read more
You can use Enumerable.Range(0, 10);. Example: var seq = Enumerable.Range(0, 10); MSDN page here.
Warning: boost::zip_iterator and boost::combine as of Boost 1.63.0 (2016 Dec 26) will cause undefined behavior if the length of the input containers are not the same (it may crash or iterate beyond the end). Starting from Boost 1.56.0 (2014 Aug 7) you could use boost::combine (the function exists in earlier versions but undocumented): #include <boost/range/combine.hpp> … Read more