slice

问题 I have a sized byte array that I got after doing md5.Sum() . data := []byte("testing") var pass string var b [16]byte b = md5.Sum(data) pass = string(b) The error: cannot convert b (type [16]byte) to type string I find the solution at this problem Change to: pass = string(b[:]) But why can not use it like this? pass = string(b) 回答1: Short answer is because the Go Language Specification does not permit it. Quoting from the Go Language Specification: Conversions: A non-constant value x can be

问题 I was trying to understand what is the difference between spread syntax vs slice method in the following approach. suppose I want to make an actual copy of an array, I can probably easily do it using spread syntax var fruits = ["Banana", "Chips" , "Orange", "Lemon", "Apple", "Mango"] var newCitrus = [...fruits] If I console.log this ["Banana", "Chips", "Orange", "Lemon", "Apple", "Mango"] but I can also create a copy of an array using the slice method. Considering the same array above, if I

问题 I'm looking for a way to easily determine if all not None items in a list occur in a single continuous slice. I'll use integers as examples of not None items. For example, the list [None, None, 1, 2, 3, None, None] meets my requirements for continuous integer entries. By contrast, [1, 2, None, None, 3, None] is not continuous, because there are None entries between integers. Some more examples to make this a clear as possible. Continuous : [1, 2, 3, None, None] [None, None, 1, 2, 3] [None, 1,

问题 As I only now noticed after commenting on this answer, slices in Python 3 return shallow copies of whatever they're slicing rather than views. Why is this still the case? Even leaving aside numpy's usage of views rather than copies for slicing, the fact that dict.keys , dict.values , and dict.items all return views in Python 3, and that there are many other aspects of Python 3 geared towards greater use of iterators, makes it seem that there would have been a movement towards slices becoming

问题 I have a NSMutableArray whose count is 10 and I want to extract the last 5 values and store them in another array. How can I do this? 回答1: I think that - (NSArray *) subarrayWithRange:(NSRange)range (doc) might help you. NSRange theRange; theRange.location = [wholeArray count] - 5; theRange.length = 5; NSArray *result = [wholeArray subarrayWithRange:theRange]; EDIT : Be careful to check that your array has at least five elements, else, subarrayWithRange will throw an exception. 回答2: Use

问题 I have some code where I repeatedly need to repeatedly broadcast arrays in complex ways, for example: a = b[np.newaxis, ..., :, np.newaxis] * c[..., np.newaxis, np.newaxis, :] Is there an object to which I can store these slicing specifications? i.e. (but obviously this doesn't work): s1 = magic([np.newaxis, ..., :, np.newaxis]) s2 = magic([..., np.newaxis, np.newaxis, :]) Edit: perhaps this could be done with numpy.broadcast_to, but it's unclear how exactly while making sure that the correct

问题 This is my first post so please "Go" easy on me. :) ... I am quite familiar with many traditional programming languages but I am new to Go and having trouble understanding the use of slices and ranges. The program code and comments below illustrate my consternation. Thank you! package main import ( "fmt" "time" ) type myStruct struct { Name string Count int } Wrote my own Mod function because I could not find on in the Go libraries. func modMe(mod int, value int) int { var m int var ret int m

问题 I'm developing a network application in Golang. I have a slice of IP addresses. Each time a request comes I use net.LookupIP(host) to find out IP address of host which returns a slice of net.IP . What is the best approach to compare these? By the way in Python we have a set data structure which makes above question so easy to resolve but what about Go? 回答1: With a "set" Building our set There is no builtin Set type in Go, but you can elegantly use a map[Type]bool as a set, e.g.: // Create a

问题 I have the following array: var arr = ["Toyota", "Hyundai", "Honda", "Mazda"]; I want to slice each element backwards, like: var arr = ["Toyota", "Hyundai", "Honda", "Mazda"].slice(-2); so it will return: arr = ["Toyo", "Hyund", "Hon", "Maz"]; Is it possible? or is there anyway of doing this? 回答1: You can't use slice directly, as it has a different meaning with an array and will return you a list of array elements. var arr = ["Toyota", "Hyundai", "Honda", "Mazda"] arr.slice(0, -2) // returns

问题 I was reading through Go's compress/flate package, and I found this odd piece of code [1]: n := int32(len(list)) list = list[0 : n+1] list[n] = maxNode() In context, list is guaranteed to be pointing to an array with more data after. This is a private function, so it can't be misused outside the library. To me, this seems like a scary hack that should be a runtime exception. For example, the following D code generates a RangeError: auto x = [1, 2, 3]; auto y = x[0 .. 2]; y = y[0 .. 3];