closures

问题 This question already has an answer here : When should I add mut to closures? (1 answer) Closed last month . Why do I need to make this closure variable mutable? The closure isn't returning anything, therefore nothing is being stored in the closure variable. This closure is only capturing a value from the environment and incrementing it. fn main() { let mut x = 1; let mut y = || x = x + 1; y(); println!("{}", x); } 回答1: Essentially, this is a consequence of one of Rust's soundness rules – you

问题 I am wanting to return multiple values from the apply() function and place them in separate columns in R but I keep getting errors. What I am trying to do is this: experiments$result1, experiments$result2, experiments$result3 <- apply(experiments, 1, function(row) #Some analysis here #return x, y, and z for column result1, result2, and result3 x, y, z ) Maybe this is the wrong approach to the problem. Experiments is a data frame with several columns of data. I am wanting to append columns

问题 func (this *l) PostUpload(ctx *Context) { //ctx.Response.Status = 500 l, err := models.NewL(this.Config) go func() { err = l.Save(file) if err != nil { ctx.Response.Status = 500 ctx.Response.Body = err } else { ctx.Response.Status = 204 } }() } How to change ctx.Response.Status value inside the goroutine closure? 回答1: You have no guarantee to observe changes made to the value of a variable in another goroutine without synchronization . See The Go Memory Model for details. So if you want to

问题 func (this *l) PostUpload(ctx *Context) { //ctx.Response.Status = 500 l, err := models.NewL(this.Config) go func() { err = l.Save(file) if err != nil { ctx.Response.Status = 500 ctx.Response.Body = err } else { ctx.Response.Status = 204 } }() } How to change ctx.Response.Status value inside the goroutine closure? 回答1: You have no guarantee to observe changes made to the value of a variable in another goroutine without synchronization . See The Go Memory Model for details. So if you want to

问题 This question already has answers here : How to mock external dependencies in tests? [duplicate] (1 answer) How to mock specific methods but not all of them in Rust? (2 answers) How can I test stdin and stdout? (1 answer) Is there a way of detecting whether code is being called from tests in Rust? (1 answer) What is the proper way to use the `cfg!` macro to choose between multiple implementations? (1 answer) Closed 8 days ago . I'm trying to run unit tests on a function reducer . reducer

问题 I am trying a very simple tentative to insert and select to/from MySql using vertx for the first time. It is funny to me that I can build and debug the application but I never get either ar.succeeded or failed. How to execute the insert and select bellow? Do I have to enclose somehow client.query and subscribe it? I am complete stuck. All examples on internet I see follow this approach. package com.mybank import io.vertx.kotlin.mysqlclient.mySQLConnectOptionsOf import io.vertx.kotlin

问题 I am trying a very simple tentative to insert and select to/from MySql using vertx for the first time. It is funny to me that I can build and debug the application but I never get either ar.succeeded or failed. How to execute the insert and select bellow? Do I have to enclose somehow client.query and subscribe it? I am complete stuck. All examples on internet I see follow this approach. package com.mybank import io.vertx.kotlin.mysqlclient.mySQLConnectOptionsOf import io.vertx.kotlin

来源： https://stackoverflow.com/questions/64496302/in-swift-5-what-is-a-way-to-compare-pointers-to-two-closures

来源： https://stackoverflow.com/questions/63966103/how-to-tell-when-a-variable-goes-out-of-scope

来源： https://stackoverflow.com/questions/23100401/creating-a-list-of-functions-in-python-python-function-closure-bug