slice

How to insert a new element in between all elements of a Ruby array?

匿名 (未验证) 提交于 2019-12-03 03:08:02
可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效,请关闭广告屏蔽插件后再试): 问题: I have an Array and want to insert a new element in between all elements, someway like the join method. For example, I have [1, [], "333"] and what I need is [1, {}, [], {}, "333"] Note a new empty hash was inserted in between all elements. Edit: Currently what I have is: irb(main):028:0> a = [1, [], "333"] => [1, [], "333"] irb(main):029:0> a = a.inject([]){|x, y| x << y; x << {}; x} => [1, {}, [], {}, "333", {}] irb(main):030:0> a.pop => {} irb(main):031:0> a => [1, {}, [], {}, "333"] irb(main):032:0> I want to know the best way. 回答1: [1,

How does one write a DELETE CASCADE for postgres?

匿名 (未验证) 提交于 2019-12-03 03:04:01
可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效,请关闭广告屏蔽插件后再试): 问题: I'm manually constructing a DELETE CASCADE statement for postgres. I have a 'transaction' and a 'slice' table, related as shown below: Table "public.slice" Column | Type | Modifiers ----------+------+----------- id | text | not null name | text | Referenced by: TABLE "transaction" CONSTRAINT "transaction_slice_id_fkey" FOREIGN KEY (slice_id) REFERENCES slice(id) Table "public.transaction" Column | Type | Modifiers ----------+------+----------- id | text | not null slice_id | text | Referenced by: TABLE "classification_item" CONSTRAINT

How to avoid re-implementing sort.Interface for similar golang structs

匿名 (未验证) 提交于 2019-12-03 03:03:02
可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效,请关闭广告屏蔽插件后再试): 问题: There is one problem bothering me in Golang. Say I have 2 structs: type Dog struct { Name string Breed string Age int } type Cat struct { Name string FavoriteFood string Age int } And when I try to sort []*Dog and []*Cat by Age, I have to define 2 different sort struct like: type SortCat []*Cat func (c SortCat) Len() int {//..} func (c SortCat) Swap(i, j int) {//..} func (c SortCat) Less(i, j int) bool {//..} type SortDog []*Dog func (c SortDog) Len() int {//..} func (c SortDog) Swap(i, j int) {//..} func (c SortDog) Less(i, j int) bool {//.

Go: Append if unique

旧时模样 提交于 2019-12-03 02:55:26
问题 Is there a way to check slices/maps for the presence of a value? I would like to add a value to a slice only if it does not exist in the slice. This works, but it seems verbose. Is there a beter way to do this? orgSlice := []int{1, 2, 3} newSlice := []int{} newInt := 2 newSlice = append(newSlice, newInt) for _, v := range orgSlice { if v != newInt { newSlice = append(newSlice, v) } } newSlice == [2 1 3] 回答1: Your approach would take linear time for each insertion. A better way would be to use

How to use AVSampleBufferDisplayLayer in iOS 8 for RTP H264 Streams with GStreamer?

匿名 (未验证) 提交于 2019-12-03 02:50:02
可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效,请关闭广告屏蔽插件后再试): 问题: After getting notice of the HW-H264-Decoder being available to programmers in iOS 8, I want to use it now. There is a nice introduction to 'Direct Access to Video Encoding and Decoding' from WWDC 2014 out there. You can take a look here . Based on Case 1 there, I started to develop an Application, that should be able to get an H264-RTP-UDP-Stream from GStreamer, sink it into an 'appsink'-element to get direct access to the NAL Units and do the conversion to create CMSampleBuffers, which my AVSampleBufferDisplayLayer can display then. The

How to slice a deque? [duplicate]

匿名 (未验证) 提交于 2019-12-03 02:50:02
可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效,请关闭广告屏蔽插件后再试): 问题: This question already has an answer here: Use slice notation with collections.deque 4 answers I've changed some code that used a list to using a deque. I can no longer slice into it, as I get the error: TypeError: sequence index must be integer, not 'slice' Here's a REPL that shows the problem. >>> import collections >>> d = collections.deque() >>> for i in range(3): ... d.append(i) ... >>> d deque([0, 1, 2]) >>> d[2:] Traceback (most recent call last): File "<stdin>", line 1, in <module> TypeError: sequence index must be integer, not 'slice

How To Stop Installation of Multiple Slice APK In Android Studio 2.3

匿名 (未验证) 提交于 2019-12-03 02:47:02
可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效,请关闭广告屏蔽插件后再试): 问题: After updating the android studio to version 2.3. i am facing issue during installation on android device from android studio. here attaching the output raised in console before and after updating the android studio. Before updated to android studio 2.3 $ adb push E:\mynewapp\TestDemo\TestDemo\app\build\outputs\apk\app-debug.apk /data/local/tmp/com.example.gangsofcoder.testdemo $ adb shell pm install -r "/data/local/tmp/com.example.gangsofcoder.testdemo" pkg: /data/local/tmp/com.example.gangsofcoder.testdemo Success After updated to android

Convert array to slice in Go

匿名 (未验证) 提交于 2019-12-03 02:47:02
可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效,请关闭广告屏蔽插件后再试): 问题: This seems like it would be a fairly common thing and abundant examples across the interwebs, but I can't seem to find an example of how to convert an [32]byte to []byte . I have a function that I call from an external lib that returns an array func Foo() [32]byte {...} I then need to pass that result to a different function for further processing. func Bar(b []byte) { ... } Unforunately, if I try to call d := Foo() Bar(d) I get cannot convert d (type [32]byte) to type []byte Doing []byte(d) isn't much better. How do I do this, especially

Golang append an item to a slice

匿名 (未验证) 提交于 2019-12-03 02:44:02
可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效,请关闭广告屏蔽插件后再试): 由 翻译 强力驱动 问题: Why does a remain the same? Does append() generate a new slice? package main import ( "fmt" ) var a = make ([] int , 7 , 8 ) func Test ( slice [] int ) { slice = append ( slice , 100 ) fmt . Println ( slice ) } func main () { for i := 0 ; i < 7 ; i ++ { a [ i ] = i } Test ( a ) fmt . Println ( a ) } 回答1: In your example the slice argument of the Test function receives a copy of the variable a in the caller's scope. Since a slice variable holds a "slice descriptor" which merely references an underlying array, in your Test function

ClassNotFoundException: Didn&#039;t find class “android.support.constraint.ConstraintLayout” on path

匿名 (未验证) 提交于 2019-12-03 02:41:02
可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效,请关闭广告屏蔽插件后再试): 问题: I was working with some libraries so I had to edit Gradle settings. Since my app wasn't working, I restored it with Local history in Android studio but It still doesn't work. Errors returned are reported here 05-04 23:26:34.953 28017-28017/? I/art: Late-enabling -Xcheck:jni 05-04 23:26:35.217 28017-28017/com.quintabi.facchini.myshop W/System: ClassLoader referenced unknown path: /data/app/com.quintabi.facchini.myshop-2/lib/arm 05-04 23:26:35.233 28017-28017/com.quintabi.facchini.myshop I/InstantRun: starting instant run server: is main