Disclaimer: I am not asking if the upper-bound stopargument of slice()and range() is exclusive or how to use these functions. Calls to the rangeand slicefunctions, as well as the slice notation [start:stop] all refer to sets of integers. range([start], stop[, step]) slice([start], stop[, step]) In all these, the stop integer is excluded. I am wondering … Read more
We can easily do that with maps: item, ok := myMap[“index”] But not with slices: item, ok := mySlice[3] // panic! Surprised this wasn’t asked before. Maybe I’m on the wrong mental model with Go slices? Answer There is no sparse slices in Go, so you could simply check the length: if len(mySlice) > 3 … Read more
Is there an equivalent of list slicing [1:] from Python in C++ with vectors? I simply want to get all but the first element from a vector. Python’s list slicing operator: list1 = [1, 2, 3] list2 = list1[1:] print(list2) # [2, 3] C++ Desired result: std::vector<int> v1 = {1, 2, 3}; std::vector<int> v2; v2 … Read more
Powershell’s array notation has rather bizarre, albeit documented, behavior for slicing the end of arrays. This section from the official documentation sums up the bizarreness rather well: Negative numbers count from the end of the array. For example, “-1” refers to the last element of the array. To display the last three elements of the … Read more
id = ’01d0′; document.write(‘<br/>’+id.substr(0,-2)); How can I take a string like ’01d0and get the01` (all except the last two chars)? In PHP I would use substr(0,-2) but this doesn’t seem to work in JavaScript. How can I make this work? Answer You are looking for slice() (also see MDC) id.slice(0, -2) AttributionSource : Link , … Read more
Is it possible to initialize an slice with all 1’s like in python? PYTHON: onesArray = np.ones(5) onesList = [1]*5 GOLANG onesSlice := make([]int, 5) for i:= 0; i < len(onesSlice); i++{ onesSlice[i] = 1 } Is it possible to do better than this? Answer Yes but you have to use a different syntax. oneSlice … Read more
How would you extract items 3..6 efficiently, elegantly and pythonically from the following deque without altering it: from collections import deque q = deque(”,maxlen=10) for i in range(10,20): q.append(i) the slice notation doesn’t seem to work with deque… Answer import itertools output = list(itertools.islice(q, 3, 7)) For example: >>> import collections, itertools >>> q = … Read more
I have an array of strings, and I’d like to exclude values that start in foo_ OR are longer than 7 characters. I can loop through each element, run the if statement, and add it to a slice along the way. But I was curious if there was an idiomatic or more golang-like way of … Read more
Situation: I’ve a slice of values and need to pick up a randomly chosen value from it. Then I want to concatenate it with a fixed string. This is my code so far: func main() { //create the reasons slice and append reasons to it reasons := make([]string, 0) reasons = append(reasons, “Locked out”, “Pipes … Read more
I’m having some trouble figuring out how to slice python lists, it is illustrated as follows: >>> test = range(10) >>> test [0, 1, 2, 3, 4, 5, 6, 7, 8, 9] >>> test[3:-1] [3, 4, 5, 6, 7, 8] >>> test[3:0] [] >>> test[3:1] [] >>> test [0, 1, 2, 3, 4, 5, 6, … Read more
