Use modulus : var len = array.length; var current = array[i]; var previous = array[(i+len-1)%len]; var next = array[(i+1)%len]; Note the +len when getting the previous: the reason we need this is to avoid negative indexes, due to the way modulus works (very unfortunately, -x% is -(x%))
I believe the proper way to do this is to use natatime, from List::MoreUtils: from the docs: natatime BLOCK LIST Creates an array iterator, for looping over an array in chunks of $n items at a time. (n at a time, get it?). An example is probably a better explanation than I could give in …
So how can I properly save the results of the operations in variable names based on the list I iterate over? You don’t need to. Variables registered for a task that has with_items have different format, they contain results for all items. – hosts: localhost gather_facts: no vars: images: – foo – bar tasks: – …
In this situation changing while() to for() is not an optimization. There is simply no way to know from bytecode which one was used in a source code. There are many situations when: while(x) is the same as: for(;x;) Suppose we have a three similar java applications – one with while() statement, and two with …
The answer the majority of the time is it does not matter. The number of items in the loop (even what one might consider a “large” number of items, say in the thousands) isn’t going to have an impact on the code. Of course, if you identify this as a bottleneck in your situation, by …
Yes, just have your block accept an argument: some_value.times{ |index| puts index } #=> 0 #=> 1 #=> 2 #=> … or some_value.times do |index| puts index end #=> 0 #=> 1 #=> 2 #=> …
It is by design. See the docs at https://docs.python.org/3/library/warnings.html: Repetitions of a particular warning for the same source location are typically suppressed. You can override this behavior by adding a filter with the keyword “always”, as in: import warnings warnings.simplefilter(‘always’, UserWarning) for i in range(10): print(i) warnings.warn(‘this is a warning message’)
Stream.forEach is not a loop and it’s not designed for being terminated using something like break. If the stream is a parallel stream the lambda body could be executed on different threads at the same time (not easy to break that and it could easily produce incorrect results). Better use a iterator with a while …
The reasons are optimizations only. If the compiler can assume that all loops without side effects terminate, it does not have to prove that. If the non-terminating loops were allowed, the compiler would be allowed to perform certain optimizations only if it could prove termination, that is impossible in general so it would turn into …