小编bra*_*orm的帖子

我一直在阅读网络上的文章,以了解以下key类型之间的差异.但这对我来说似乎很难掌握.实例肯定有助于更好地理解.

primary key,
partition key, 
composite key 
clustering key

我的HTML有一个被调用的类.required,它被分配给必需的字段.这是html:

<form action="/accounts/register/" method="post" role="form" class="form-horizontal">
    <input type='hidden' name='csrfmiddlewaretoken' value='brGfMU16YyyG2QEcpLqhb3Zh8AvkYkJt' />
    <div class="form-group required">
       <label class="col-md-2 control-label">Username</label>
       <div class="col-md-4">
         <input class="form-control" id="id_username" maxlength="30" name="username" placeholder="Username" required="required" title="" type="text" />
       </div>
    </div>
    <div class="form-group required"><label class="col-md-2 control-label">E-mail</label><div class="col-md-4"><input class="form-control" id="id_email" name="email" placeholder="E-mail" required="required" title="" type="email" /></div></div>
    <div class="form-group required"><label class="col-md-2 control-label">Password</label><div class="col-md-4"><input class="form-control" id="id_password1" name="password1" placeholder="Password" required="required" title="" type="password" /></div></div>
    <div class="form-group required"><label class="col-md-2 control-label">Password (again)</label><div class="col-md-4"><input class="form-control" id="id_password2" name="password2" placeholder="Password (again)" required="required" title="" type="password" /></div></div>
    <div class="form-group required"><label …

我有一些节点来自我想要映射到图表的脚本.在下面,我想使用箭头从A到D,并且边缘也可能有颜色(红色或其他东西).这基本上就像所有其他节点都存在时从A到D的路径.您可以将每个节点想象为城市,从A到D行进需要方向(带箭头).下面的代码构建了图表

import networkx as nx
import numpy as np
import matplotlib.pyplot as plt

G = nx.Graph()
G.add_edges_from(
    [('A', 'B'), ('A', 'C'), ('D', 'B'), ('E', 'C'), ('E', 'F'),
     ('B', 'H'), ('B', 'G'), ('B', 'F'), ('C', 'G')])

val_map = {'A': 1.0,
           'D': 0.5714285714285714,
           'H': 0.0}

values = [val_map.get(node, 0.25) for node in G.nodes()]

nx.draw(G, cmap = plt.get_cmap('jet'), node_color = values)
plt.show()

但我想要一些像图中所示的东西.

第一个图像的箭头和第二个图像的红色边缘.谢谢

我正在学习用来ExectorService汇集threads和发送任务.我有一个简单的程序如下

import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;


class Processor implements Runnable {

    private int id;

    public Processor(int id) {
        this.id = id;
    }

    public void run() {
        System.out.println("Starting: " + id);

        try {
            Thread.sleep(5000);
        } catch (InterruptedException e) {
            System.out.println("sorry, being interupted, good bye!");
            System.out.println("Interrupted "+Thread.currentThread().getName());
            e.printStackTrace();    
        }

        System.out.println("Completed: " + id);
    }
}


public class ExecutorExample {

    public static void main(String[] args) {
        Boolean isCompleted=false;

        ExecutorService executor = Executors.newFixedThreadPool(2);

        for(int i=0; i<5; i++) {
            executor.execute(new …

n log n > n- 但这就像是一段pseudo-linear感情.如果n=1 billion,log n~30;

所以,n log n将30 billion是30 X n,顺序n.我想知道这个时间复杂度之间n log n and n的差异在现实生活中是否显着.

例如:quick select在未排序数组中查找第k个元素是O(n)使用快速选择算法.

如果我对数组进行排序并找到第k个元素,那就是O(n log n).要排序一个数组1 trillion的元素,我会很60 times慢,如果我做quicksort和index it.

我正在使用弹簧靴1.4.0.RELEASE.我正在为我的控制器类编写测试.我得到以下异常.

org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'com.concur.cognos.authentication.service.ServiceControllerITTest': Unsatisfied dependency expressed through field 'restTemplate': No qualifying bean of type [org.springframework.boot.test.web.client.TestRestTemplate] found for dependency [org.springframework.boot.test.web.client.TestRestTemplate]: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [org.springframework.boot.test.web.client.TestRestTemplate] found for dependency [org.springframework.boot.test.web.client.TestRestTemplate]: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}

这是我的测试课

public class ServiceControllerITTest extends ApplicationTests {

    @Autowired …

来自python wiki: In Py3.0, the cmp parameter was removed entirely (as part of a larger effort to simplify and unify the language, eliminating the conflict between rich comparisons and the __cmp__ methods).

我不明白为什么在py3.0中删除cmp的原因

考虑这个例子:

>>> def numeric_compare(x, y):
        return x - y
>>> sorted([5, 2, 4, 1, 3], cmp=numeric_compare)
[1, 2, 3, 4, 5]

现在考虑这个版本(推荐并与3.0兼容):

def cmp_to_key(mycmp):
    'Convert a cmp= function into a key= function'
    class K(object):
        def __init__(self, obj, *args):
            self.obj = obj
        def __lt__(self, other):
            return …

我们有一个即将投入生产的Spring项目.目前,该项目正在使用Apache Http Client.有一种使用RestTemplateas 的想法HttpClient.

我正在四处寻找使用RestTemplate结束的任何明显优势Apache's.此外,了解RestTemplate在其实现中的HTTP传输是很有趣的.Apache Http Client已被多个团体使用多年,并且享有良好的声誉.

我们有冒险搬到RestTemplate哪儿？

此外,该博客指出需要为生产配置RestTemplate,尽管配置很少.

谢谢

请考虑以下代码:

class AA { }

class BB extends AA { }

public class Testing {

    public static void main(String[] args) {
        BB[] arr = new BB[10];
        AA[] arr2 = arr;

        BB b = new BB();
        AA a = new AA();
        arr2[0] = a; // ArrayStoreException at runtime
        arr2[1] = b;

        List<BB> listBB = new ArrayList<>();
        List listAA = listBB;
        listAA.add("hello world.txt");

    }
}

在上面的例子中,ArrayStoreException我尝试了arr2[0] = a.这意味着数组会记住它必须接受的类型.但是List不记得他们了.它只是编译并运行良好.在ClassCastException当我检索对象将被抛出BB.

所以问题是:

1. 数组如何记住它的类型(我知道它被称为"具体化").这究竟是怎么发生的？

2. 并且为什么只有阵列才能获得这种功率,但是ArrayList …

此链接说明如何使用pytest捕获控制台输出.我尝试了以下简单的代码,但是我收到了错误

import sys
import pytest
def f(name):
    print "hello "+ name

def test_add(capsys):
    f("Tom")
    out,err=capsys.readouterr()
    assert out=="hello Tom"


test_add(sys.stdout)

输出:

python test_pytest.py 
hello Tom
Traceback (most recent call last):
  File "test_pytest.py", line 12, in <module>
    test_add(sys.stdout)
  File "test_pytest.py", line 8, in test_add
    out,err=capsys.readouterr()
AttributeError: 'file' object has no attribute 'readouterr'

什么是错的,需要什么修复？谢谢

编辑:根据评论,我改变了capfd,但我仍然得到相同的错误

import sys
import pytest
def f(name):
    print "hello "+ name

def test_add(capfd):
    f("Tom")
    out,err=capfd.readouterr()
    assert out=="hello Tom"


test_add(sys.stdout)