问题列表 - 第47622页

假设我有以下表格结构:

t1
-------------
id // row id
userID_follower // this user is a follows another member
userID_following  // other member that this user 

是否可以运行单个查询来组合以下两个:

1. 这个人关注了多少用户

   从t1 WHERE userID_follower =".$ myID"中选择COUNT(id).".

2. 有多少用户关注此人

   从t1 WHERE userID_following =".$ myID"中选择COUNT(id).

谢谢.

如何用javascript在浏览器html输出中打印常用语言的源代码？

我的意思是有一些缩进和代码格式.目前我只有 http://alexgorbatchev.com/SyntaxHighlighter/ 用于着色语法.但我还想要一些缩进和其他格式.

示例:user放入一些代码.系统格式并突出显示浏览器视图中的代码.so->是否有用于格式化代码的通用代码格式化程序？最好的JavaScript

我很感激任何帮助.

我目前正在使用liquibase.xml文件来创建表table_a.我的一个领域是<column name="state" type="ENUM('yes','no')"> 我使用postgresql作为我的DBMS.有什么像枚举数据类型？我在这里读过http://wiki.postgresql.org/wiki/Enum

postgresql没有这样的数据类型.CREATE TYPE函数用于创建此数据类型.我仍然不知道如何在liquibase中制作它.

有什么建议？

我输入了以下程序:

#include <stdio.h>

int main(void) {
    int a = 3;
    int b = 42;

    printf("a = %d\nb = %d\n", a, b);

    printf("Exchanging values.\n");
    a ^= b ^= a ^= b;

    printf("a = %d\nb = %d\n", a, b);

    return 0;
}

没关系 当我尝试编译它时,我得到了这个:

$ gcc test.c -o test -Wall -Wextra -ansi -pedantic-errors
test.c: In function ‘main’:
test.c:11: warning: operation on ‘a’ may be undefined

这几乎是标准代码,不是吗？

为什么会触发警告？据我所知,int只要您使用C的标准实现,就会默认实现按位XOR .

非常感谢你.

我有一个看起来像这样的数组.

[{"title"=>"ga:browser=Internet Explorer", "dimensions"=>[{:browser=>"Internet Explorer"}], "metrics"=>[{:pageviews=>2047}], "id"=>"http://www.google.com/analytics/feeds/data?ids=ga:12316&ga:browser=Internet%20Explorer&start-date=2010-02-27&end-date=2011-02-27", "updated"=>#}, {"title"=>"ga:browser=Safari", "dimensions"=>[{:browser=>"Safari"}], "metrics"=>[{:pageviews=>1196}], "id"=>"http://www.google.com/analytics/feeds/data?ids=ga:12316&ga:browser=Safari&start-date=2010-02-27&end-date=2011-02-27", "updated"=>#}, {"title"=>"ga:browser=Firefox", "dimensions"=>[{:browser=>"Firefox"}], "metrics"=>[{:pageviews=>835}], "id"=>"http://www.google.com/analytics/feeds/data?ids=ga:12316&ga:browser=Firefox&start-date=2010-02-27&end-date=2011-02-27", "updated"=>#}, {"title"=>"ga:browser=Chrome", "dimensions"=>[{:browser=>"Chrome"}], "metrics"=>[{:pageviews=>227}], "id"=>"http://www.google.com/analytics/feeds/data?ids=ga:12316&ga:browser=Chrome&start-date=2010-02-27&end-date=2011-02-27", "updated"=>#}, {"title"=>"ga:browser=Mozilla Compatible Agent", "dimensions"=>[{:browser=>"Mozilla Compatible Agent"}], "metrics"=>[{:pageviews=>60}], "id"=>"http://www.google.com/analytics/feeds/data?ids=ga:12316&ga:browser=Mozilla%20Compatible%20Agent&start-date=2010-02-27&end-date=2011-02-27", "updated"=>#}, {"title"=>"ga:browser=Opera", "dimensions"=>[{:browser=>"Opera"}], "metrics"=>[{:pageviews=>33}], "id"=>"http://www.google.com/analytics/feeds/data?ids=ga:12316&ga:browser=Opera&start-date=2010-02-27&end-date=2011-02-27", "updated"=>#}, {"title"=>"ga:browser=BlackBerry9700", "dimensions"=>[{:browser=>"BlackBerry9700"}], "metrics"=>[{:pageviews=>8}], "id"=>"http://www.google.com/analytics/feeds/data?ids=ga:12316&ga:browser=BlackBerry9700&start-date=2010-02-27&end-date=2011-02-27", "updated"=>#}, {"title"=>"ga:browser=BlackBerry8900", "dimensions"=>[{:browser=>"BlackBerry8900"}], "metrics"=>[{:pageviews=>7}], "id"=>"http://www.google.com/analytics/feeds/data?ids=ga:12316&ga:browser=BlackBerry8900&start-date=2010-02-27&end-date=2011-02-27", "updated"=>#}, {"title"=>"ga:browser=Mozilla", "dimensions"=>[{:browser=>"Mozilla"}], "metrics"=>[{:pageviews=>2}], "id"=>"http://www.google.com/analytics/feeds/data?ids=ga:12316&ga:browser=Mozilla&start-date=2010-02-27&end-date=2011-02-27", "updated"=>#}, {"title"=>"ga:browser=Camino", "dimensions"=>[{:browser=>"Camino"}], "metrics"=>[{:pageviews=>1}], "id"=>"http://www.google.com/analytics/feeds/data?ids=ga:12316&ga:browser=Camino&start-date=2010-02-27&end-date=2011-02-27", "updated"=>#}]

有没有一种简单的方法来展平它,使它成为:

[2047,1196,835,227,60,33,8,7,2,1]

并且

['Internet Explorer','Firefox','Chrome','Mozilla Compatible Agent','Opera','BlackBerry9700','Mozilla','Camino']

我需要的是返回token对象作为adapter.authenticate()放置在线程中的操作的结果.不知道如何从那里返回一个物体,请指教.谢谢.

public Token authenticate(final String email, final String password) {

        Thread mThread = new Thread(new Runnable() {

            @Override
            public void run() {
                try {
                    token = adapter.authenticate(email, password); // I need token to return with authenticate() method.

                } catch (NotAuthenticatedException e) {

                }
            }
        });
        mThread.start();
    }

我创建了一个微型ec2实例.安装了所有必要的网络软件,mysql和git.从该实例中创建了一个AMI.由于该实例使用EBS作为其根设备,因此在创建AMI时也使用了EBS快照.

我终止了正在运行的实例.然后,我尝试创建一个亚马逊机器映像(AMI)的实例,新实例启动以及新的EBS卷附加到实例.

现在,当我使用我的密钥对通过我的ssh密钥登录到该实例时,使用命令作为其公共DNS地址

ssh -i aws/mykey.pem ubuntu@thepublicdnsname

它说

ssh: connect to host <thepublickdnsname> port 22: Connection refused

为什么会这样呢？我能够通过ssh使用相同的密钥连接到我的第一个实例.现在新实例是精确的副本,我无法登录它.对此有任何帮助......？我错过了什么吗？

我使用相同的密钥对从AMI创建第二个新实例.

我有一个EditText,一个按钮和一个微调器.单击该按钮时,微调器将添加一个新项目,其中包含您在EditText中输入的名称.但这是问题,我的adapter.add()方法似乎不起作用...这是我的代码:

  bt1 = (Button)this.findViewById(R.id.AddBtn);
            et = (EditText)this.findViewById(R.id.newSpinnerItemText);  
            spinner = (Spinner)this.findViewById(R.id.dynamicSpinner);

            adapter = ArrayAdapter.createFromResource(
                    this, R.array.simple_from_length, android.R.layout.simple_spinner_item);

            adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);

            spinner.setAdapter(adapter);

            bt1.setOnClickListener(new View.OnClickListener() {

                @Override
                public void onClick(View v) {
                    String temp = et.getText().toString();

                    adapter.add(temp);
                //    adapter.notifyDataSetChanged();
                    spinner.setAdapter(adapter);

                }
            });

这个文件的错误:

02-27 18:01:17.728: ERROR/AndroidRuntime(1982): java.lang.UnsupportedOperationException
02-27 18:01:17.728: ERROR/AndroidRuntime(1982):     at java.util.AbstractList.add(AbstractList.java:410)
02-27 18:01:17.728: ERROR/AndroidRuntime(1982):     at java.util.AbstractList.add(AbstractList.java:432)
02-27 18:01:17.728: ERROR/AndroidRuntime(1982):     at android.widget.ArrayAdapter.add(ArrayAdapter.java:178)
02-27 18:01:17.728: ERROR/AndroidRuntime(1982):     at org.example.SpinnerKiran.SpinnerKiran$1.onClick(SpinnerKiran.java:56)
02-27 18:01:17.728: ERROR/AndroidRuntime(1982):     at android.view.View.performClick(View.java:2179)
02-27 18:01:17.728: ERROR/AndroidRuntime(1982):     at android.view.View.onTouchEvent(View.java:3828)
02-27 18:01:17.728: ERROR/AndroidRuntime(1982):     at android.widget.TextView.onTouchEvent(TextView.java:6291)
02-27 18:01:17.728: ERROR/AndroidRuntime(1982): …

我尝试使用DirectAdmin导入,当我选择CSV而不使用LOAD DATA时 - 我收到错误"第1行的CSV输入中的字段计数无效".

当我尝试使用LOAD DATA时,我收到以下错误:"#1148 - 此MySQL版本不允许使用该命令."

CSV是从MS Access数据库的MS Access中创建的.

这是前两行:

"product_id","vendor_id"," product_parent_id","product_sku","product_s_desc ","product_desc","product_thumb_image ","product_full_image","product_publish","product_weight","product_weight_uom ","product_length ","product_width","product_height ","product_lwh_uom ","disp_order","price","sale","product_url ","product_in_stock","product_available_date","product_availability ","product_special ","product_discount_id ","ship_code_id ","cdate ","mdate ","product_name ","product_sales ","attribute ","custom_attribute ","product_tax_id ","product_unit ","product_packaging ","child_options ","quantity_options ","child_option_ids ","product_order_levels "
41,2,0,1,,,"resized/Krug-Rose-Champagne-lg.jpg","Krug-Rose-Champagne-lg.jpg","Y","750.0000","grams","4.0000","4.0000",14,,14,3516,0,,,1296518400,,"N",0,"NULL ",1296574622,1297953843,"???? ????",0,,,2,"piece ",65537,"N,N,N,N,N,Y,20%,10%, ","none,0,0,1 ",,"0,0 "

Python中的8个皇后问题.

嗨!我只是开始教Python,所以有人可以解释下面写的代码(在Internet上找到)吗？有些代码对我来说很复杂.请解释一下.谢谢.问题接近代码.

BOARD_SIZE = 8

def under_attack(col, queens): # (col, queens) What is their meaning? What do I need to write it this field? 
    left = right = col
    for r, c in reversed(queens): # What does reversed means in this loop? For what reson do we need r and c (their meaning is 0 by default?)?
        left, right = left-1, right+1
        if c in (left, col, right):
            return True
    return False

def solve(n):
    if n == 0: return [[]] …