对不起,我不能在问题标题中更具体,但我正在阅读一些Go代码,我遇到了这种形式的函数声明:
func (h handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
...
}
来自https://github.com/mattermost/platform/blob/master/api/context.go
func (s *GracefulServer) BlockingClose() bool {
...
}
来自https://github.com/braintree/manners/blob/master/server.go
什么是(h handler)与(s *GracefulServer)括号之间是什么意思？考虑到括号之间事物的含义,整个函数声明意味着什么？
这与Go的功能和方法的区别是什么不重复？:这个问题来找我,因为我不知道函数名之前括号中的内容是什么,不是因为我想知道函数和方法之间有什么区别......如果我知道这个声明是一种方法我就不会'我们首先提出了这个问题.如果某人有一天和我有同样的疑问,我不相信她会去寻找"golang方法",因为她不知道情况就是这样.这就像想知道"sigma"字母在数学表达式之前的含义(不知道它意味着求和),并且有人说它是总和与其他事物之间差异的重复.
此外,这个问题的简短回答("它是接收者")无法回答"功能和方法之间的区别".
有没有办法自动更新.cabal文件中的build-depends字段？例如,如果我们从以下文件开始:.cabal
name: HUnit
version: 1.1.1
synopsis: A unit testing framework for Haskell
homepage: http://hunit.sourceforge.net/
category: Testing
author: Dean Herington
license: BSD3
license-file: LICENSE
cabal-version: >= 1.10
build-type: Simple
library
build-depends: base >= 2 && < 4
exposed-modules: Test.HUnit.Base, Test.HUnit.Lang,
Test.HUnit.Terminal, Test.HUnit.Text, Test.HUnit
default-extensions: CPP
然后,安装一个包:
cabal install warp
现在,我必须添加warp >=3.0 && <3.1到该build-depends字段,使文件看起来像这样:
name: HUnit
version: 1.1.1
synopsis: A unit testing framework for Haskell
homepage: http://hunit.sourceforge.net/
category: Testing
author: Dean Herington
license: …我有以下组件:
// Hello.js
export default (React) => ({name}) => {
return (
<div>
Hello {name ? name : 'Stranger'}!
</div>
)
}
// App.js
import createHello from './Hello'
export default (React) => () => {
const Hello = createHello(React)
const helloProps = {
name: 'Jane'
}
return (
<Hello { ...helloProps } />
)
}
// index.js
import React from 'react'
import { render } from 'react-dom'
import createApp from './App'
const App = createApp(React)
render(
<App />,
document.getElementById('app')
) …我有两个型号,Person并且Pet,我希望Person能够有很多宠物,但Pet到属于只有一个人:
defmodule MyApp.Person do
use MyApp.Web, :model
alias MyApp.Pet
schema "persons" do
field :name, :string
has_many :pets, Pet
timestamps()
end
def changeset(struct, params \\ %{}) do
struct
|> cast(params, [])
|> validate_required([])
end
end
和
defmodule MyApp.Pet do
use MyApp.Web, :model
alias MyApp.Person
schema "pets" do
field :name, :string
belongs_to :person, Person
timestamps()
end
def changeset(struct, params \\ %{}) do
struct
|> cast(params, [])
|> validate_required([]) …我想要一个Elixir函数来生成一个n参数出现列表,类似于Haskell的replicate函数:
Input: replicate 3 5
Output: [5,5,5]
Input: replicate 5 "aa"
Output: ["aa","aa","aa","aa","aa"]
Input: replicate 5 'a'
Output: "aaaaa"
我已经创建了一个"复制"整数n时间的函数:
import String
def replicate(number, n)
String.duplicate(to_string(number), n)
|> split("", trim: true)
|> Enum.map(fn n -> String.to_integer(n) end
end
但这与规格不符:(.你能帮帮我吗？
我想将数据用作手动编写的JSON文件,而不是从数据库中获取数据.假设我的数据是这样的:
[
{ "id": 1, "name": "Alice", "email": "alice@example.com" },
{ "id": 2, "name": "Bob", "email": "bob@example" },
{ "id": 3, "name": "Charles", "email": "charles@example.com"}
]
它写在一个名为的文件中MOCK_DATA.json.当我访问localhost:port/api/v1/users网址时,我该怎么做才能呈现此文件？如何localhost:port/api/v1/users/1显示网址{ "id": 1, "name": "Alice", "email": "alice@example.com" }？
我已经实现了以下功能：
/**
* Returns a function h , which is the composition of the functions f and g.
*/
def compose[A, B, C](g: B => C, f: A => B): A => C = f.andThen(g)
我正在尝试用ScalaCheck测试它。我可以生成以下测试，这些测试可以编译并通过：
import org.scalatest.prop.PropertyChecks
import org.scalatest.{FlatSpec, Matchers}
class ComposeSpec extends FlatSpec with Matchers with PropertyChecks {
"Compose" should "return a function h , which is the composition of the
functions f and g" in {
forAll { (a: Int, g: Int => Int, f: Int …假设我有以下React组件:
import React from 'react'
import AppBar from 'material-ui/lib/app-bar'
class NavBar extends React.Component {
render () {
return (
<div>
<AppBar
title='My NavBar Title'
/>
</div>
)
}
}
export default NavBar
我想设置一个测试,以确保用户在渲染时看到一个材料-ui AppBarNavBar,使用Tape和Enzyme:
import NavBar from './NavBar'
import React from 'react'
import test from 'tape'
// import { I don't know exactly what to import here. Maybe `shallow`? } from 'enzyme'
test('NavBar component test', (assert) => {
test('I should see …我有两个模型Owner和Property，其中 的架构Owner有一个embeds_many声明，如下所示：
defmodule MyApp.Owner do
use MyApp.Web, :model
alias MyApp.Property
schema "owners" do
field name, :string
embeds_many :properties, Property
timestamps()
end
@doc """
Builds a changeset based on the `struct` and `params`.
"""
def changeset(struct, params \\ %{}) do
struct
|> cast(params, [])
|> validate_required([])
end
end
和这个：
defmodule MyApp.Property do
use MyApp.Web, :model
embedded_schema do
field :name, :string
field :value, :float, default: 0
end
def changeset(struct, params \\ %{}) do
struct …假设我有一个像这样的字符串：
"IgotthistextfromapdfIscraped.HowdoIsplitthis?"
我想制作：
"I got this text from a pdf I scraped. How do I split this?"
我该怎么做？
我想创建一个脚本,对用户提供的参数进行插入排序,如下所示:
$ insertionSort 1 2 110 39
我希望它能回归:
[1 2 39 110]
但它返回:
[1 110 2 39]
我认为这是因为os.Args数组中的元素是字符串.所以,我的问题是如何将os.Args数组的元素转换为整数？这是我的代码:
package main
import (
"fmt"
"os"
"reflect"
"strconv"
)
func main() {
A := os.Args[1:]
for i := 0; i <= len(A); i++ {
strconv.Atoi(A[i])
fmt.Println(reflect.TypeOf(A[i]))
}
for j := 1; j < len(A); j++ {
key := A[j]
i := j - 1
for i >= 0 && A[i] > key {
A[i+1] = A[i]
i = i - 1
A[i+1] …我正在尝试使用以下界面编写Cobol程序:
接收明确的加密密钥和明文,并使用3DES算法返回加密文本.
我尝试了这三种方法:
77 CSNBSYE PIC X(7) VALUE 'CSNBSYE'.
01 CSNBSYE-PARAMETERS.
02 RETURN-CODE PIC 9(8) COMP.
02 REASON-CODE PIC 9(8) COMP.
02 EXIT-DATA-LENGTH PIC 9(8) COMP.
02 EXIT-DATA PIC X(32).
02 RULE-ARRAY-COUNT PIC 9(8) COMP.
02 RULE-ARRAY PIC X(8).
02 KEY-IDENTIFIER-LENGTH PIC 9(8) COMP.
02 KEY-IDENTIFIER PIC X(32).
02 KEY-PARMS-LENGTH PIC 9(8) COMP.
02 KEY-PARMS PIC X(32).
02 BLOCK-SIZE PIC 9(8) COMP.
02 INIT-VECTOR-LENGTH PIC …我一直试图isInfixOf从Data.List模块中理解功能,但无济于事.这是代码:
isInfixOf :: (Eq a) => [a] -> [a] -> Bool
isInfixOf needle haystack = any (isPrefixOf needle) (tails haystack)
-- Example:
--
-- >isInfixOf "Haskell" "I really like Haskell." -> True
-- >isInfixOf "Ial" "I really like Haskell." -> False
该any如果列表中的至少一个项目满足条件,则返回true.它的类型是(a -> Bool) -> [a] -> Bool
该isPrefixOf和tails功能的代码是这些:
isPrefixOf :: (Eq a) => [a] -> [a] -> Bool
isPrefixOf [] _ = True
isPrefixOf _ [] = False …