Programs & Examples On #Delphi 2007

Delphi 2007 is a specific version of Delphi. Delphi 2007 was released in March 2007, and was available as a standalone product or as part of RAD Studio 2007.

Why does CreateProcess give error 193 (%1 is not a valid Win32 app)

If you are Clion/anyOtherJetBrainsIDE user, and yourFile.exe cause this problem, just delete it and let the app create and link it with libs from a scratch. It helps.

Which one is the best PDF-API for PHP?

personally i'd rather go with tcpdf which is an ehnanced and mantained version of fpdf.

How to frame two for loops in list comprehension python

This should do it:

[entry for tag in tags for entry in entries if tag in entry]

Kill detached screen session

add this to your ~/.bashrc:

alias cleanscreen="screen -ls | tail -n +2 | head -n -2 | awk '{print $1}'| xargs -I{} screen -S {} -X quit"

Then use cleanscreen to clean all screen session.

PermGen elimination in JDK 8

Reasons of ignoring these argument is permanent generation has been removed in HotSpot for JDK8 because of following drawbacks

  • Fixed size at startup – difficult to tune.
  • Internal Hotspot types were Java objects : Could move with full GC, opaque, not strongly typed and hard to debug, needed meta-metadata.
  • Simplify full collections : Special iterators for metadata for each collector
  • Want to deallocate class data concurrently and not during GC pause
  • Enable future improvements that were limited by PermGen.

The Permanent Generation (PermGen) space has completely been removed and is kind of replaced by a new space called Metaspace. The consequences of the PermGen removal is that obviously the PermSize and MaxPermSize JVM arguments are ignored and you will never get a java.lang.OutOfMemoryError: PermGen error.

Advantages of MetaSpace

  • Take advantage of Java Language Specification property : Classes and associated metadata lifetimes match class loader’s
  • Per loader storage area – Metaspace
  • Linear allocation only
  • No individual reclamation (except for RedefineClasses and class loading failure)
  • No GC scan or compaction
  • No relocation for metaspace objects

Metaspace Tuning

The maximum metaspace size can be set using the -XX:MaxMetaspaceSize flag, and the default is unlimited, which means that only your system memory is the limit. The -XX:MetaspaceSize tuning flag defines the initial size of metaspace If you don’t specify this flag, the Metaspace will dynamically re-size depending of the application demand at runtime.

Change enables other optimizations and features in the future

  • Application class data sharing
  • Young collection optimizations, G1 class unloading
  • Metadata size reductions and internal JVM footprint projects

There is improved GC performace also.

Could not extract response: no suitable HttpMessageConverter found for response type

As Artem Bilan said, this problem occures because MappingJackson2HttpMessageConverter supports response with application/json content-type only. If you can't change server code, but can change client code(I had such case), you can change content-type header with interceptor:

restTemplate.getInterceptors().add((request, body, execution) -> {
            ClientHttpResponse response = execution.execute(request,body);
            response.getHeaders().setContentType(MediaType.APPLICATION_JSON);
            return response;
        });

Imported a csv-dataset to R but the values becomes factors

I'm new to R as well and faced the exact same problem. But then I looked at my data and noticed that it is being caused due to the fact that my csv file was using a comma separator (,) in all numeric columns (Ex: 1,233,444.56 instead of 1233444.56).

I removed the comma separator in my csv file and then reloaded into R. My data frame now recognises all columns as numbers.

I'm sure there's a way to handle this within the read.csv function itself.

How do I determine the size of my array in C?

The macro ARRAYELEMENTCOUNT(x) that everyone is making use of evaluates incorrectly. This, realistically, is just a sensitive matter, because you can't have expressions that result in an 'array' type.

/* Compile as: CL /P "macro.c" */
# define ARRAYELEMENTCOUNT(x) (sizeof (x) / sizeof (x[0]))

ARRAYELEMENTCOUNT(p + 1);

Actually evaluates as:

(sizeof (p + 1) / sizeof (p + 1[0]));

Whereas

/* Compile as: CL /P "macro.c" */
# define ARRAYELEMENTCOUNT(x) (sizeof (x) / sizeof (x)[0])

ARRAYELEMENTCOUNT(p + 1);

It correctly evaluates to:

(sizeof (p + 1) / sizeof (p + 1)[0]);

This really doesn't have a lot to do with the size of arrays explicitly. I've just noticed a lot of errors from not truly observing how the C preprocessor works. You always wrap the macro parameter, not an expression in might be involved in.


This is correct; my example was a bad one. But that's actually exactly what should happen. As I previously mentioned p + 1 will end up as a pointer type and invalidate the entire macro (just like if you attempted to use the macro in a function with a pointer parameter).

At the end of the day, in this particular instance, the fault doesn't really matter (so I'm just wasting everyone's time; huzzah!), because you don't have expressions with a type of 'array'. But really the point about preprocessor evaluation subtles I think is an important one.

How can I add new array elements at the beginning of an array in Javascript?

Without Mutate

Actually, all unshift/push and shift/pop mutate the origin array.

The unshift/push add an item to the existed array from begin/end and shift/pop remove an item from the beginning/end of an array.

But there are few ways to add items to an array without a mutation. the result is a new array, to add to the end of array use below code:

const originArray = ['one', 'two', 'three'];
const newItem = 4;

const newArray = originArray.concat(newItem); // ES5
const newArray2 = [...originArray, newItem]; // ES6+

To add to begin of original array use below code:

const originArray = ['one', 'two', 'three'];
const newItem = 0;

const newArray = (originArray.slice().reverse().concat(newItem)).reverse(); // ES5
const newArray2 = [newItem, ...originArray]; // ES6+

With the above way, you add to the beginning/end of an array without a mutation.

Mongoose's find method with $or condition does not work properly

I solved it through googling:

var ObjectId = require('mongoose').Types.ObjectId;
var objId = new ObjectId( (param.length < 12) ? "123456789012" : param );
// You should make string 'param' as ObjectId type. To avoid exception, 
// the 'param' must consist of more than 12 characters.

User.find( { $or:[ {'_id':objId}, {'name':param}, {'nickname':param} ]}, 
  function(err,docs){
    if(!err) res.send(docs);
});

ASP.NET Core Web API Authentication

You can implement a middleware which handles Basic authentication.

public async Task Invoke(HttpContext context)
{
    var authHeader = context.Request.Headers.Get("Authorization");
    if (authHeader != null && authHeader.StartsWith("basic", StringComparison.OrdinalIgnoreCase))
    {
        var token = authHeader.Substring("Basic ".Length).Trim();
        System.Console.WriteLine(token);
        var credentialstring = Encoding.UTF8.GetString(Convert.FromBase64String(token));
        var credentials = credentialstring.Split(':');
        if(credentials[0] == "admin" && credentials[1] == "admin")
        {
            var claims = new[] { new Claim("name", credentials[0]), new Claim(ClaimTypes.Role, "Admin") };
            var identity = new ClaimsIdentity(claims, "Basic");
            context.User = new ClaimsPrincipal(identity);
        }
    }
    else
    {
        context.Response.StatusCode = 401;
        context.Response.Headers.Set("WWW-Authenticate", "Basic realm=\"dotnetthoughts.net\"");
    }
    await _next(context);
}

This code is written in a beta version of asp.net core. Hope it helps.

Android Studio Gradle DSL method not found: 'android()' -- Error(17,0)

I also meet that problems,and just delete bottom code:

DELETE THESE LINES:
android {
    compileSdkVersion 22
    buildToolsVersion '22.0.1'
}

it worked?

Can the Unix list command 'ls' output numerical chmod permissions?

You can use the following command

stat -c "%a %n" *

Also you can use any filename or directoryname instead of * to get a specific result.

On Mac, you can use

stat -f '%A %N' *

Why do I get an UnsupportedOperationException when trying to remove an element from a List?

This UnsupportedOperationException comes when you try to perform some operation on collection where its not allowed and in your case, When you call Arrays.asList it does not return a java.util.ArrayList. It returns a java.util.Arrays$ArrayList which is an immutable list. You cannot add to it and you cannot remove from it.

how does array[100] = {0} set the entire array to 0?

It depends where you put this initialisation.

If the array is static as in

char array[100] = {0};

int main(void)
{
...
}

then it is the compiler that reserves the 100 0 bytes in the data segement of the program. In this case you could have omitted the initialiser.

If your array is auto, then it is another story.

int foo(void)
{
char array[100] = {0};
...
}

In this case at every call of the function foo you will have a hidden memset.

The code above is equivalent to

int foo(void)
{ 
char array[100];

memset(array, 0, sizeof(array));
....
}

and if you omit the initializer your array will contain random data (the data of the stack).

If your local array is declared static like in

int foo(void)
{ 
static char array[100] = {0};
...
}

then it is technically the same case as the first one.

Convert any object to a byte[]

You could use the built-in serialization tools in the framework and serialize to a MemoryStream. This may be the most straightforward option, but might produce a larger byte[] than may be strictly necessary for your scenario.

If that is the case, you could utilize reflection to iterate over the fields and/or properties in the object to be serialized and manually write them to the MemoryStream, calling the serialization recursively if needed to serialize non-trivial types. This method is more complex and will take more time to implement, but allows you much more control over the serialized stream.

How to list physical disks?

Might want to include the old A: and B: drives as you never know who might be using them! I got tired of USB drives bumping my two SDHC drives that are just for Readyboost. I had been assigning them to High letters Z: Y: with a utility that will assign drive letters to devices as you wish. I wondered.... Can I make a Readyboost drive letter A: ? YES! Can I put my second SDHC drive letter as B: ? YES!

I've used Floppy Drives back in the day, never thought that A: or B: would come in handy for Readyboost.

My point is, don't assume A: & B: will not be used by anyone for anything You might even find the old SUBST command being used!

What is the difference between `Enum.name()` and `Enum.toString()`?

Use toString() when you want to present information to a user (including a developer looking at a log). Never rely in your code on toString() giving a specific value. Never test it against a specific string. If your code breaks when someone correctly changes the toString() return, then it was already broken.

If you need to get the exact name used to declare the enum constant, you should use name() as toString may have been overridden.

Jquery, set value of td in a table?

use .html() along with selector to get/set HTML:

 $('#detailInfo').html('changed value');

Is it possible to convert char[] to char* in C?

Well, I'm not sure to understand your question...

In C, Char[] and Char* are the same thing.

Edit : thanks for this interesting link.

How to uncommit my last commit in Git

If you commit to the wrong branch

While on the wrong branch:

  1. git log -2 gives you hashes of 2 last commits, let's say $prev and $last
  2. git checkout $prev checkout correct commit
  3. git checkout -b new-feature-branch creates a new branch for the feature
  4. git cherry-pick $last patches a branch with your changes

Then you can follow one of the methods suggested above to remove your commit from the first branch.

How can I modify a saved Microsoft Access 2007 or 2010 Import Specification?

Another great option is the free V-Tools addin for Microsoft Access. Among other helpful tools it has a form to edit and save the Import/Export specifications.

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Note: As of version 1.83, there is a bug in enumerating the code pages on Windows 10. (Apparently due to a missing/changed API function in Windows 10) The tools still works great, you just need to comment out a few lines of code or step past it in the debug window.

This has been a real life-saver for me in editing a complex import spec for our online orders.

Importing PNG files into Numpy?

Using a (very) commonly used package is prefered:

import matplotlib.pyplot as plt
im = plt.imread('image.png')

remove / reset inherited css from an element

Try this: Create a plain div without any style or content outside of the red div. Now you can use a loop over all styles of the plain div and assign then to your inner div to reset all styles.

Of course this doesn't work if someone assigns styles to all divs (i.e. without using a class. CSS would be div { ... }).

The usual solution for problems like this is to give your div a distinct class. That way, web designers of the sites can adjust the styling of your div to fit into the rest of the design.

Yahoo Finance API

Here's a simple scraper I created in c# to get streaming quote data printed out to a console. It should be easily converted to java. Based on the following post:

http://blog.underdog-projects.net/2009/02/bringing-the-yahoo-finance-stream-to-the-shell/

Not too fancy (i.e. no regex etc), just a fast & dirty solution.

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Net;
using System.Text;
using System.Web.Script.Serialization;

namespace WebDataAddin
{
    public class YahooConstants
    {
        public const string AskPrice = "a00";
        public const string BidPrice = "b00";
        public const string DayRangeLow = "g00";
        public const string DayRangeHigh = "h00";
        public const string MarketCap = "j10";
        public const string Volume = "v00";
        public const string AskSize = "a50";
        public const string BidSize = "b60";
        public const string EcnBid = "b30";
        public const string EcnBidSize = "o50";
        public const string EcnExtHrBid = "z03";
        public const string EcnExtHrBidSize = "z04";
        public const string EcnAsk = "b20";
        public const string EcnAskSize = "o40";
        public const string EcnExtHrAsk = "z05";
        public const string EcnExtHrAskSize = "z07";
        public const string EcnDayHigh = "h01";
        public const string EcnDayLow = "g01";
        public const string EcnExtHrDayHigh = "h02";
        public const string EcnExtHrDayLow = "g11";
        public const string LastTradeTimeUnixEpochformat = "t10";
        public const string EcnQuoteLastTime = "t50";
        public const string EcnExtHourTime = "t51";
        public const string RtQuoteLastTime = "t53";
        public const string RtExtHourQuoteLastTime = "t54";
        public const string LastTrade = "l10";
        public const string EcnQuoteLastValue = "l90";
        public const string EcnExtHourPrice = "l91";
        public const string RtQuoteLastValue = "l84";
        public const string RtExtHourQuoteLastValue = "l86";
        public const string QuoteChangeAbsolute = "c10";
        public const string EcnQuoteAfterHourChangeAbsolute = "c81";
        public const string EcnQuoteChangeAbsolute = "c60";
        public const string EcnExtHourChange1 = "z02";
        public const string EcnExtHourChange2 = "z08";
        public const string RtQuoteChangeAbsolute = "c63";
        public const string RtExtHourQuoteAfterHourChangeAbsolute = "c85";
        public const string RtExtHourQuoteChangeAbsolute = "c64";
        public const string QuoteChangePercent = "p20";
        public const string EcnQuoteAfterHourChangePercent = "c82";
        public const string EcnQuoteChangePercent = "p40";
        public const string EcnExtHourPercentChange1 = "p41";
        public const string EcnExtHourPercentChange2 = "z09";
        public const string RtQuoteChangePercent = "p43";
        public const string RtExtHourQuoteAfterHourChangePercent = "c86";
        public const string RtExtHourQuoteChangePercent = "p44";

        public static readonly IDictionary<string, string> CodeMap = typeof(YahooConstants).GetFields().
            Where(field => field.FieldType == typeof(string)).
            ToDictionary(field => ((string)field.GetValue(null)).ToUpper(), field => field.Name);
    }

    public static class StringBuilderExtensions
    {
        public static bool HasPrefix(this StringBuilder builder, string prefix)
        {
            return ContainsAtIndex(builder, prefix, 0);
        }

        public static bool HasSuffix(this StringBuilder builder, string suffix)
        {
            return ContainsAtIndex(builder, suffix, builder.Length - suffix.Length);
        }

        private static bool ContainsAtIndex(this StringBuilder builder, string str, int index)
        {
            if (builder != null && !string.IsNullOrEmpty(str) && index >= 0
                && builder.Length >= str.Length + index)
            {
                return !str.Where((t, i) => builder[index + i] != t).Any();
            }
            return false;
        }
    }

    public class WebDataAddin
    {
        public const string ScriptStart = "<script>";
        public const string ScriptEnd = "</script>";

        public const string MessageStart = "try{parent.yfs_";
        public const string MessageEnd = ");}catch(e){}";

        public const string DataMessage = "u1f(";
        public const string InfoMessage = "mktmcb(";


        protected static T ParseJson<T>(string json)
        {
            // parse json - max acceptable value retrieved from 
            //http://forums.asp.net/t/1343461.aspx
            var deserializer = new JavaScriptSerializer { MaxJsonLength = 2147483647 };
            return deserializer.Deserialize<T>(json);
        }

        public static void Main()
        {
            const string symbols = "GBPUSD=X,SPY,MSFT,BAC,QQQ,GOOG";
            // these are constants in the YahooConstants enum above
            const string attrs = "b00,b60,a00,a50";
            const string url = "http://streamerapi.finance.yahoo.com/streamer/1.0?s={0}&k={1}&r=0&callback=parent.yfs_u1f&mktmcb=parent.yfs_mktmcb&gencallback=parent.yfs_gencb&region=US&lang=en-US&localize=0&mu=1";

            var req = WebRequest.Create(string.Format(url, symbols, attrs));
            req.Proxy.Credentials = CredentialCache.DefaultCredentials;
            var missingCodes = new HashSet<string>();
            var response = req.GetResponse();
            if(response != null)
            {
                var stream = response.GetResponseStream();
                if (stream != null)
                {
                    using (var reader = new StreamReader(stream))
                    {
                        var builder = new StringBuilder();
                        var initialPayloadReceived = false;
                        while (!reader.EndOfStream)
                        {
                            var c = (char)reader.Read();
                            builder.Append(c);
                            if(!initialPayloadReceived)
                            {
                                if (builder.HasSuffix(ScriptStart))
                                {
                                    // chop off the first part, and re-append the
                                    // script tag (this is all we care about)
                                    builder.Clear();
                                    builder.Append(ScriptStart);
                                    initialPayloadReceived = true;
                                }
                            }
                            else
                            {
                                // check if we have a fully formed message
                                // (check suffix first to avoid re-checking 
                                // the prefix over and over)
                                if (builder.HasSuffix(ScriptEnd) &&
                                    builder.HasPrefix(ScriptStart))
                                {
                                    var chop = ScriptStart.Length + MessageStart.Length;
                                    var javascript = builder.ToString(chop,
                                        builder.Length - ScriptEnd.Length - MessageEnd.Length - chop);

                                    if (javascript.StartsWith(DataMessage))
                                    {
                                        var json = ParseJson<Dictionary<string, object>>(
                                            javascript.Substring(DataMessage.Length));

                                        // parse out the data. key should be the symbol

                                        foreach(var symbol in json)
                                        {
                                            Console.WriteLine("Symbol: {0}", symbol.Key);
                                            var symbolData = (Dictionary<string, object>) symbol.Value;
                                            foreach(var dataAttr in symbolData)
                                            {
                                                var codeKey = dataAttr.Key.ToUpper();
                                                if (YahooConstants.CodeMap.ContainsKey(codeKey))
                                                {
                                                    Console.WriteLine("\t{0}: {1}", YahooConstants.
                                                        CodeMap[codeKey], dataAttr.Value);
                                                } else
                                                {
                                                    missingCodes.Add(codeKey);
                                                    Console.WriteLine("\t{0}: {1} (Warning! No Code Mapping Found)", 
                                                        codeKey, dataAttr.Value);
                                                }
                                            }
                                            Console.WriteLine();
                                        }

                                    } else if(javascript.StartsWith(InfoMessage))
                                    {
                                        var json = ParseJson<Dictionary<string, object>>(
                                            javascript.Substring(InfoMessage.Length));

                                        foreach (var dataAttr in json)
                                        {
                                            Console.WriteLine("\t{0}: {1}", dataAttr.Key, dataAttr.Value);
                                        }
                                        Console.WriteLine();
                                    } else
                                    {
                                        throw new Exception("Cannot recognize the message type");
                                    }
                                    builder.Clear();
                                }
                            }
                        }
                    }
                }
            }
        }
    }
}

XAMPP on Windows - Apache not starting

I spent over 3 hours to find out solution. Actually port 80 was being used by "system" service so I tried to change port from 80 to 8080 in "httpd" file but same problem raised "port 80 is used by system". It had driven me mad for 3 hours as every thing was changed like port , localhost server etc pointing to 8080.

At last I found mistake that was server root. Basically "Server Root" in "httpd" should be pointing to apache foler of xampp. In my case that's was

ServerRoot "xampp/apache"

I just changed it as follows:

ServerRoot "C:/xampp/apache" 

It has worked successfully and now everything is running with OK status.

Sum values in a column based on date

Use pivot tables, it will definitely save you time. If you are using excel 2007+ use tables (structured references) to keep your table dynamic. However if you insist on using functions, go with Smandoli's suggestion. Again, if you are on 2007+ use SUMIFS, it's faster compared to SUMIF.

No found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations:

Look at the exception:

No qualifying bean of type [edu.java.spring.ws.dao.UserDao] found for dependency

This means that there's no bean available to fulfill that dependency. Yes, you have an implementation of the interface, but you haven't created a bean for that implementation. You have two options:

  • Annotate UserDaoImpl with @Component or @Repository, and let the component scan do the work for you, exactly as you have done with UserService.
  • Add the bean manually to your xml file, the same you have done with UserBoImpl.

Remember that if you create the bean explicitly you need to put the definition before the component scan. In this case the order is important.

Converting from byte to int in java

if you want to combine the 4 bytes into a single int you need to do

int i= (rno[0]<<24)&0xff000000|
       (rno[1]<<16)&0x00ff0000|
       (rno[2]<< 8)&0x0000ff00|
       (rno[3]<< 0)&0x000000ff;

I use 3 special operators | is the bitwise logical OR & is the logical AND and << is the left shift

in essence I combine the 4 8-bit bytes into a single 32 bit int by shifting the bytes in place and ORing them together

I also ensure any sign promotion won't affect the result with & 0xff

how to use getSharedPreferences in android

//Set Preference
SharedPreferences myPrefs = getSharedPreferences("myPrefs", MODE_WORLD_READABLE);
SharedPreferences.Editor prefsEditor;  
prefsEditor = myPrefs.edit();  
//strVersionName->Any value to be stored  
prefsEditor.putString("STOREDVALUE", strVersionName);  
prefsEditor.commit();

//Get Preferenece  
SharedPreferences myPrefs;    
myPrefs = getSharedPreferences("myPrefs", MODE_WORLD_READABLE);  
String StoredValue=myPrefs.getString("STOREDVALUE", "");

Try this..

c++ boost split string

My best guess at why you had problems with the ----- covering your first result is that you actually read the input line from a file. That line probably had a \r on the end so you ended up with something like this:

-----------test2-------test3

What happened is the machine actually printed this:

test-------test2-------test3\r-------

That means, because of the carriage return at the end of test3, that the dashes after test3 were printed over the top of the first word (and a few of the existing dashes between test and test2 but you wouldn't notice that because they were already dashes).

Android: checkbox listener

Try this:

satView = (CheckBox) findViewById(R.id.sateliteCheckBox);

satView.setOnCheckedChangeListener(new OnCheckedChangeListener() {
    @Override 
    public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
          if (buttonView.isChecked()) { 
                // checked
          } 
          else 
          {
                // not checked
          }
    }

});

Hope this helps.

What are the Android SDK build-tools, platform-tools and tools? And which version should be used?

About the version of Android SDK Build-tools, the answer is

By default, the Android SDK uses the most recent downloaded version of the Build Tools.

Source

In Eclipse, you can choose a specific version by using the sdk.buildtools property in the project.properties file.

There seems to be no official page explaining all the build tools. Here is what the Android team says about this.

The [build] tools, such as aidl, aapt, dexdump, and dx, are typically called by the Android build tools or Android Development Tools (ADT), so you rarely need to invoke these tools directly. As a general rule, you should rely on the build tools or the ADT plugin to call them as needed.

Source

Anyway, here is a synthesis of the differences between tools, platform-tools and build-tools:

  • Android SDK Tools
    • Location: $ANDROID_HOME/tools
    • Main tools: ant scripts (to build your APKs) and ddms (for debugging)
  • Android SDK Platform-tools
    • Location: $ANDROID_HOME/platform-tools
    • Main tool: adb (to manage the state of an emulator or an Android device)
  • Android SDK Build-tools
    • Location: $ANDROID_HOME/build-tools/$VERSION/
    • Documentation
    • Main tools: aapt (to generate R.java and unaligned, unsigned APKs), dx (to convert Java bytecode to Dalvik bytecode), and zipalign (to optimize your APKs)

Recursive sub folder search and return files in a list python

You should be using the dirpath which you call root. The dirnames are supplied so you can prune it if there are folders that you don't wish os.walk to recurse into.

import os
result = [os.path.join(dp, f) for dp, dn, filenames in os.walk(PATH) for f in filenames if os.path.splitext(f)[1] == '.txt']

Edit:

After the latest downvote, it occurred to me that glob is a better tool for selecting by extension.

import os
from glob import glob
result = [y for x in os.walk(PATH) for y in glob(os.path.join(x[0], '*.txt'))]

Also a generator version

from itertools import chain
result = (chain.from_iterable(glob(os.path.join(x[0], '*.txt')) for x in os.walk('.')))

Edit2 for Python 3.4+

from pathlib import Path
result = list(Path(".").rglob("*.[tT][xX][tT]"))

How to get RegistrationID using GCM in android

Here I have written a few steps for How to Get RegID and Notification starting from scratch

  1. Create/Register App on Google Cloud
  2. Setup Cloud SDK with Development
  3. Configure project for GCM
  4. Get Device Registration ID
  5. Send Push Notifications
  6. Receive Push Notifications

You can find a complete tutorial here:

Getting Started with Android Push Notification : Latest Google Cloud Messaging (GCM) - step by step complete tutorial

enter image description here

Code snippet to get Registration ID (Device Token for Push Notification).

Configure project for GCM


Update AndroidManifest file

To enable GCM in our project we need to add a few permissions to our manifest file. Go to AndroidManifest.xml and add this code: Add Permissions

<uses-permission android:name="android.permission.INTERNET”/>
<uses-permission android:name="android.permission.GET_ACCOUNTS" />
<uses-permission android:name="android.permission.WAKE_LOCK" />

<uses-permission android:name="android.permission.VIBRATE" />

<uses-permission android:name=“.permission.RECEIVE" />
<uses-permission android:name=“<your_package_name_here>.permission.C2D_MESSAGE" />
<permission android:name=“<your_package_name_here>.permission.C2D_MESSAGE"
        android:protectionLevel="signature" />

Add GCM Broadcast Receiver declaration in your application tag:

<application
        <receiver
            android:name=".GcmBroadcastReceiver"
            android:permission="com.google.android.c2dm.permission.SEND" ]]>
            <intent-filter]]>
                <action android:name="com.google.android.c2dm.intent.RECEIVE" />
                <category android:name="" />
            </intent-filter]]>

        </receiver]]>
     
<application/>

Add GCM Service declaration

<application
     <service android:name=".GcmIntentService" />
<application/>

Get Registration ID (Device Token for Push Notification)

Now Go to your Launch/Splash Activity

Add Constants and Class Variables

private final static int PLAY_SERVICES_RESOLUTION_REQUEST = 9000;
public static final String EXTRA_MESSAGE = "message";
public static final String PROPERTY_REG_ID = "registration_id";
private static final String PROPERTY_APP_VERSION = "appVersion";
private final static String TAG = "LaunchActivity";
protected String SENDER_ID = "Your_sender_id";
private GoogleCloudMessaging gcm =null;
private String regid = null;
private Context context= null;

Update OnCreate and OnResume methods

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_launch);
    context = getApplicationContext();
    if (checkPlayServices()) {
        gcm = GoogleCloudMessaging.getInstance(this);
        regid = getRegistrationId(context);

        if (regid.isEmpty()) {
            registerInBackground();
        } else {
            Log.d(TAG, "No valid Google Play Services APK found.");
        }
    }
}

@Override
protected void onResume() {
    super.onResume();
    checkPlayServices();
}


// # Implement GCM Required methods(Add below methods in LaunchActivity)

private boolean checkPlayServices() {
    int resultCode = GooglePlayServicesUtil.isGooglePlayServicesAvailable(this);
    if (resultCode != ConnectionResult.SUCCESS) {
        if (GooglePlayServicesUtil.isUserRecoverableError(resultCode)) {
            GooglePlayServicesUtil.getErrorDialog(resultCode, this,
                PLAY_SERVICES_RESOLUTION_REQUEST).show();
        } else {
            Log.d(TAG, "This device is not supported - Google Play Services.");
            finish();
        }
        return false;
    }
    return true;
}

private String getRegistrationId(Context context) {
    final SharedPreferences prefs = getGCMPreferences(context);
    String registrationId = prefs.getString(PROPERTY_REG_ID, "");
    if (registrationId.isEmpty()) {
        Log.d(TAG, "Registration ID not found.");
        return "";
    }
    int registeredVersion = prefs.getInt(PROPERTY_APP_VERSION, Integer.MIN_VALUE);
    int currentVersion = getAppVersion(context);
    if (registeredVersion != currentVersion) {
        Log.d(TAG, "App version changed.");
        return "";
    }
    return registrationId;
}

private SharedPreferences getGCMPreferences(Context context) {
    return getSharedPreferences(LaunchActivity.class.getSimpleName(),
        Context.MODE_PRIVATE);
}

private static int getAppVersion(Context context) {
    try {
        PackageInfo packageInfo = context.getPackageManager()
            .getPackageInfo(context.getPackageName(), 0);
        return packageInfo.versionCode;
    } catch (NameNotFoundException e) {
        throw new RuntimeException("Could not get package name: " + e);
    }
}


private void registerInBackground() {
    new AsyncTask() {
        @Override
        protected Object doInBackground(Object...params) {
            String msg = "";
            try {
                if (gcm == null) {
                    gcm = GoogleCloudMessaging.getInstance(context);
                }
                regid = gcm.register(SENDER_ID);
                Log.d(TAG, "########################################");
                Log.d(TAG, "Current Device's Registration ID is: " + msg);
            } catch (IOException ex) {
                msg = "Error :" + ex.getMessage();
            }
            return null;
        }
        protected void onPostExecute(Object result) {
            //to do here
        };
    }.execute(null, null, null);
}

Note : please store REGISTRATION_KEY, it is important for sending PN Message to GCM. Also keep in mind: this key will be unique for all devices and GCM will send Push Notifications by REGISTRATION_KEY only.

What does the Java assert keyword do, and when should it be used?

Assert is very useful when developing. You use it when something just cannot happen if your code is working correctly. It's easy to use, and can stay in the code for ever, because it will be turned off in real life.

If there is any chance that the condition can occur in real life, then you must handle it.

I love it, but don't know how to turn it on in Eclipse/Android/ADT . It seems to be off even when debugging. (There is a thread on this, but it refers to the 'Java vm', which does not appear in the ADT Run Configuration).

On postback, how can I check which control cause postback in Page_Init event

If you need to check which control caused the postback, then you could just directly compare ["__EVENTTARGET"] to the control you are interested in:

if (specialControl.UniqueID == Page.Request.Params["__EVENTTARGET"])
{
    /*do special stuff*/
}

This assumes you're just going to be comparing the result from any GetPostBackControl(...) extension method anyway. It may not handle EVERY situation, but if it works it is simpler. Plus, you won't scour the page looking for a control you didn't care about to begin with.

How to disable text selection using jQuery?

If you use jQuery UI, there is a method for that, but it can only handle mouse selection (i.e. CTRL+A is still working):

$('.your-element').disableSelection(); // deprecated in jQuery UI 1.9

The code is realy simple, if you don't want to use jQuery UI :

$(el).attr('unselectable','on')
     .css({'-moz-user-select':'-moz-none',
           '-moz-user-select':'none',
           '-o-user-select':'none',
           '-khtml-user-select':'none', /* you could also put this in a class */
           '-webkit-user-select':'none',/* and add the CSS class here instead */
           '-ms-user-select':'none',
           'user-select':'none'
     }).bind('selectstart', function(){ return false; });

How to skip to next iteration in jQuery.each() util?

Javascript sort of has the idea of 'truthiness' and 'falsiness'. If a variable has a value then, generally 9as you will see) it has 'truthiness' - null, or no value tends to 'falsiness'. The snippets below might help:

var temp1; 
if ( temp1 )...  // false

var temp2 = true;
if ( temp2 )...  // true

var temp3 = "";
if ( temp3 ).... // false

var temp4 = "hello world";
if ( temp4 )...  // true

Hopefully that helps?

Also, its worth checking out these videos from Douglas Crockford

update: thanks @cphpython for spotting the broken links - I've updated to point at working versions now

The Javascript language

Javascript - The Good Parts

Running Windows batch file commands asynchronously

You can use the start command to spawn background processes without launching new windows:

start /b foo.exe

The new process will not be interruptable with CTRL-C; you can kill it only with CTRL-BREAK (or by closing the window, or via Task Manager.)

Build a basic Python iterator

I see some of you doing return self in __iter__. I just wanted to note that __iter__ itself can be a generator (thus removing the need for __next__ and raising StopIteration exceptions)

class range:
  def __init__(self,a,b):
    self.a = a
    self.b = b
  def __iter__(self):
    i = self.a
    while i < self.b:
      yield i
      i+=1

Of course here one might as well directly make a generator, but for more complex classes it can be useful.

Multiple radio button groups in MVC 4 Razor

Ok here's how I fixed this

My model is a list of categories. Each category contains a list of its subcategories.
with this in mind, every time in the foreach loop, each RadioButton will have its category's ID (which is unique) as its name attribue.
And I also used Html.RadioButton instead of Html.RadioButtonFor.

Here's the final 'working' pseudo-code:

@foreach (var cat in Model.Categories)
{
  //A piece of code & html here
  @foreach (var item in cat.SubCategories)
  {
     @Html.RadioButton(item.CategoryID.ToString(), item.ID)
  }    
}

The result is:

<input name="127" type="radio" value="110">

Please note that I HAVE NOT put all these radio button groups inside a form. And I don't know if this solution will still work properly in a form.

Thanks to all of the people who helped me solve this ;)

How can I align text directly beneath an image?

I am not an expert in HTML but here is what worked for me:

<div class="img-with-text-below">
    <img src="your-image.jpg" alt="alt-text" />
    <p><center>Your text</center></p>
</div>

CSS how to make scrollable list

As per your question vertical listing have a scrollbar effect.

CSS / HTML :

_x000D_
_x000D_
nav ul{height:200px; width:18%;}_x000D_
nav ul{overflow:hidden; overflow-y:scroll;}
_x000D_
<!DOCTYPE html>_x000D_
<html>_x000D_
    <head>_x000D_
        <meta charset="utf-8">_x000D_
        <title>JS Bin</title>_x000D_
    </head>_x000D_
    <body>_x000D_
        <header>header area</header>_x000D_
        <nav>_x000D_
            <ul>_x000D_
                <li>Link 1</li>_x000D_
                <li>Link 2</li>_x000D_
                <li>Link 3</li>_x000D_
                <li>Link 4</li>_x000D_
                <li>Link 5</li>_x000D_
                <li>Link 6</li> _x000D_
                <li>Link 7</li> _x000D_
                <li>Link 8</li>_x000D_
                <li>Link 9</li>_x000D_
                <li>Link 10</li>_x000D_
                <li>Link 11</li>_x000D_
                <li>Link 13</li>_x000D_
                <li>Link 13</li>_x000D_
_x000D_
            </ul>_x000D_
        </nav>_x000D_
        _x000D_
        <footer>footer area</footer>_x000D_
    </body>_x000D_
</html>
_x000D_
_x000D_
_x000D_

SQL Sum Multiple rows into one

I tried this, but the query won't run telling me my field is invalid in the select statement because it is not contained in either an aggregate function or the GROUP BY clause. It's forcing me to keep it there. Is there a way around this?

You need to do a self-join. You can't both aggregate and preserve non-aggregated data in the same subquery. E.g.

select q2.AccountNumber, q2.Bill, q2.BillDate, q1.BillSum
from
(
SELECT AccountNumber, SUM(Bill) as BillSum
FROM Table1
GROUP BY AccountNumber
) q1,
(
select AccountNumber, Bill, BillDate
from table1
) q2
where q1.AccountNumber = q2.AccountNumber

log4j:WARN No appenders could be found for logger in web.xml

If still help, verify the name of archive, it must be exact "log4j.properties" or "log4j.xml" (case sensitive), and follow the hint by "Alain O'Dea". I was geting the same error, but after make these changes everthing works fine. just like a charm :-). hope this helps.

How can I transform string to UTF-8 in C#?

string utf8String = "Acción";
string propEncodeString = string.Empty;

byte[] utf8_Bytes = new byte[utf8String.Length];
for (int i = 0; i < utf8String.Length; ++i)
{
   utf8_Bytes[i] = (byte)utf8String[i];
}

propEncodeString = Encoding.UTF8.GetString(utf8_Bytes, 0, utf8_Bytes.Length);

Output should look like

Acción

day’s displays day's

call DecodeFromUtf8();

private static void DecodeFromUtf8()
{
    string utf8_String = "day’s";
    byte[] bytes = Encoding.Default.GetBytes(utf8_String);
    utf8_String = Encoding.UTF8.GetString(bytes);
}

php REQUEST_URI

You can either use regex, or keep on using str_replace.

Eg.

$url = parse_url($_SERVER['REQUEST_URI']);

if ($url != '/') {
    parse_str($url['query']);
    echo $id;
    echo $othervar;
}

Output will be: http://www.testing.com/123/123

Selenium webdriver click google search

Most of the answers on this page are outdated.
Here's an updated python version to search google and get all results href's:

import urllib.parse
import re
from selenium import webdriver
driver.get("https://google.com/")
q = driver.find_element_by_name('q')
q.send_keys("always look on the bright side of life monty python")
q.submit();
sleep(1)
links= driver.find_elements_by_xpath("//h3[@class='r']//a")
for link in links:
    url = urllib.parse.unquote(webElement.get_attribute("href")) # decode the url
    url = re.sub("^.*?(?:url\?q=)(.*?)&sa.*", r"\1", url, 0, re.IGNORECASE) # get the clean url

Please note that the element id/name/class (@class='r') ** will change depending on the user agent**.
The above code used PhantomJS default user agent.

In Mongoose, how do I sort by date? (node.js)

Sorting in Mongoose has evolved over the releases such that some of these answers are no longer valid. As of the 4.1.x release of Mongoose, a descending sort on the date field can be done in any of the following ways:

    Room.find({}).sort('-date').exec((err, docs) => { ... });
    Room.find({}).sort({date: -1}).exec((err, docs) => { ... });
    Room.find({}).sort({date: 'desc'}).exec((err, docs) => { ... });
    Room.find({}).sort({date: 'descending'}).exec((err, docs) => { ... });
    Room.find({}).sort([['date', -1]]).exec((err, docs) => { ... });
    Room.find({}, null, {sort: '-date'}, (err, docs) => { ... });
    Room.find({}, null, {sort: {date: -1}}, (err, docs) => { ... });

For an ascending sort, omit the - prefix on the string version or use values of 1, asc, or ascending.

How to switch databases in psql?

At the PSQL prompt, you can do:

\connect (or \c) dbname

How do I update Ruby Gems from behind a Proxy (ISA-NTLM)

This totally worked:

gem install --http-proxy http://COMPANY.PROXY.ADDRESS $gem_name

Does overflow:hidden applied to <body> work on iPhone Safari?

After many days trying, I found this solution that worked for me:

touch-action: none;
-ms-touch-action: none;

HttpClient 4.0.1 - how to release connection?

To answer my own question: to release the connection (and any other resources associated with the request) you must close the InputStream returned by the HttpEntity:

InputStream is = entity.getContent();

.... process the input stream ....

is.close();       // releases all resources

From the docs

Unlocking tables if thread is lost

how will I know that some tables are locked?

You can use SHOW OPEN TABLES command to view locked tables.

how do I unlock tables manually?

If you know the session ID that locked tables - 'SELECT CONNECTION_ID()', then you can run KILL command to terminate session and unlock tables.

Pretty Printing a pandas dataframe

If you are in Jupyter notebook, you could run the following code to interactively display the dataframe in a well formatted table.

This answer builds on the to_html('temp.html') answer above, but instead of creating a file displays the well formatted table directly in the notebook:

from IPython.display import display, HTML

display(HTML(df.to_html()))

Credit for this code due to example at: Show DataFrame as table in iPython Notebook

Convert Pandas Column to DateTime

If you have more than one column to be converted you can do the following:

df[["col1", "col2", "col3"]] = df[["col1", "col2", "col3"]].apply(pd.to_datetime)

Setting the Vim background colors

Using set bg=dark with a white background can produce nearly unreadable text in some syntax highlighting schemes. Instead, you can change the overall colorscheme to something that looks good in your terminal. The colorscheme file should set the background attribute for you appropriately. Also, for more information see:

:h color

Batch / Find And Edit Lines in TXT file

You can always use "FAR" = "Find and Replace". It's written under java, so it works where Java works (pretty much everywhere). Works with directories and subdirectories, searches and replaces within files, also can renames them. Also can rename bulk files.Licence = free, for both individuals or comapnies. Very fast and maintained by the developer. Find it here: http://findandreplace.sourceforge.net/

Also you can use GrepWin. Works pretty much the same. You can find it here: http://tools.tortoisesvn.net/grepWin.html

Opening database file from within SQLite command-line shell

The command within the Sqlite shell to open a database is .open

The syntax is,

sqlite> .open dbasename.db

If it is a new database that you would like to create and open, it is

sqlite> .open --new dbasename.db

If the database is existing in a different folder, the path has to be mentioned like this:

sqlite> .open D:/MainFolder/SubFolder/...database.db

In Windows Command shell, you should use '\' to represent a directory, but in SQLite directories are represented by '/'. If you still prefer to use the Windows notation, you should use an escape sequence for every '\'

How to remove all white spaces in java

Try:

  string output = YourString.replaceAll("\\s","")

s - indicates space character (tab characters etc)

What are good ways to prevent SQL injection?

SQL injection can be a tricky problem but there are ways around it. Your risk is reduced your risk simply by using an ORM like Linq2Entities, Linq2SQL, NHibrenate. However you can have SQL injection problems even with them.

The main thing with SQL injection is user controlled input (as is with XSS). In the most simple example if you have a login form (I hope you never have one that just does this) that takes a username and password.

SELECT * FROM Users WHERE Username = '" + username + "' AND password = '" + password + "'"

If a user were to input the following for the username Admin' -- the SQL Statement would look like this when executing against the database.

SELECT * FROM Users WHERE Username = 'Admin' --' AND password = ''

In this simple case using a paramaterized query (which is what an ORM does) would remove your risk. You also have a the issue of a lesser known SQL injection attack vector and that's with stored procedures. In this case even if you use a paramaterized query or an ORM you would still have a SQL injection problem. Stored procedures can contain execute commands, and those commands themselves may be suceptable to SQL injection attacks.

CREATE PROCEDURE SP_GetLogin @username varchar(100), @password varchar(100) AS
DECLARE @sql nvarchar(4000)
SELECT @sql = ' SELECT * FROM users' +
              ' FROM Product Where username = ''' + @username + ''' AND password = '''+@password+''''

EXECUTE sp_executesql @sql

So this example would have the same SQL injection problem as the previous one even if you use paramaterized queries or an ORM. And although the example seems silly you'd be surprised as to how often something like this is written.

My recommendations would be to use an ORM to immediately reduce your chances of having a SQL injection problem, and then learn to spot code and stored procedures which can have the problem and work to fix them. I don't recommend using ADO.NET (SqlClient, SqlCommand etc...) directly unless you have to, not because it's somehow not safe to use it with parameters but because it's that much easier to get lazy and just start writing a SQL query using strings and just ignoring the parameters. ORMS do a great job of forcing you to use parameters because it's just what they do.

Next Visit the OWASP site on SQL injection https://www.owasp.org/index.php/SQL_Injection and use the SQL injection cheat sheet to make sure you can spot and take out any issues that will arise in your code. https://www.owasp.org/index.php/SQL_Injection_Prevention_Cheat_Sheet finally I would say put in place a good code review between you and other developers at your company where you can review each others code for things like SQL injection and XSS. A lot of times programmers miss this stuff because they're trying to rush out some feature and don't spend too much time on reviewing their code.

Query to list number of records in each table in a database

You could try this:

SELECT  OBJECT_SCHEMA_NAME(ps.object_Id) AS [schemaname],
        OBJECT_NAME(ps.object_id) AS [tablename],
        row_count AS [rows]
FROM sys.dm_db_partition_stats ps
WHERE OBJECT_SCHEMA_NAME(ps.object_Id) <> 'sys' AND ps.index_id < 2
ORDER BY 
        OBJECT_SCHEMA_NAME(ps.object_Id),
        OBJECT_NAME(ps.object_id)

C++/CLI Converting from System::String^ to std::string

I spent hours trying to convert a windows form listbox ToString value to a standard string so that I could use it with fstream to output to a txt file. My Visual Studio didn't come with marshal header files which several answers I found said to use. After so much trial and error I finally found a solution to the problem that just uses System::Runtime::InteropServices:

void MarshalString ( String ^ s, string& os ) {
   using namespace Runtime::InteropServices;
   const char* chars = 
      (const char*)(Marshal::StringToHGlobalAnsi(s)).ToPointer();
   os = chars;
   Marshal::FreeHGlobal(IntPtr((void*)chars));
}

//this is the code to use the function:
scheduleBox->SetSelected(0,true);
string a = "test";
String ^ c = gcnew String(scheduleBox->SelectedItem->ToString());
MarshalString(c, a);
filestream << a;

And here is the MSDN page with the example: http://msdn.microsoft.com/en-us/library/1b4az623(v=vs.80).aspx

I know it's a pretty simple solution but this took me HOURS of troubleshooting and visiting several forums to finally find something that worked.

MySQL - Using If Then Else in MySQL UPDATE or SELECT Queries

Here's a query to update a table based on a comparison of another table. If record is not found in tableB, it will update the "active" value to "n". If it's found, will set the value to NULL

UPDATE tableA
LEFT JOIN tableB ON tableA.id = tableB.id
SET active = IF(tableB.id IS NULL, 'n', NULL)";

Hope this helps someone else.

Command not found error in Bash variable assignment

When you define any variable then you do not have to put in any extra spaces.

E.g.

name = "Stack Overflow"  
// it is not valid, you will get an error saying- "Command not found"

So remove spaces:

name="Stack Overflow" 

and it will work fine.

Put search icon near textbox using bootstrap

You can do it in pure CSS using the :after pseudo-element and getting creative with the margins.

Here's an example, using Font Awesome for the search icon:

_x000D_
_x000D_
.search-box-container input {_x000D_
  padding: 5px 20px 5px 5px;_x000D_
}_x000D_
_x000D_
.search-box-container:after {_x000D_
    content: "\f002";_x000D_
    font-family: FontAwesome;_x000D_
    margin-left: -25px;_x000D_
    margin-right: 25px;_x000D_
}
_x000D_
<!-- font awesome -->_x000D_
<link href="https://maxcdn.bootstrapcdn.com/font-awesome/4.7.0/css/font-awesome.min.css" rel="stylesheet"/>_x000D_
_x000D_
_x000D_
<div class="search-box-container">_x000D_
  <input type="text" placeholder="Search..."  />_x000D_
</div>
_x000D_
_x000D_
_x000D_

Replace all double quotes within String

The following regex will work for both:

  text = text.replaceAll("('|\")", "\\\\$1");

Deleting an element from an array in PHP

unset doesn't change the index, but array_splice does:

$arrayName = array('1' => 'somevalue',
                   '2' => 'somevalue1',
                   '3' => 'somevalue3',
                   500 => 'somevalue500',
                  );


    echo $arrayName['500'];
    //somevalue500
    array_splice($arrayName, 1, 2);

    print_r($arrayName);
    //Array ( [0] => somevalue [1] => somevalue500 )


    $arrayName = array( '1' => 'somevalue',
                        '2' => 'somevalue1',
                        '3' => 'somevalue3',
                        500 => 'somevalue500',
                      );


    echo $arrayName['500'];
    //somevalue500
    unset($arrayName[1]);

    print_r($arrayName);
    //Array ( [0] => somevalue [1] => somevalue500 )

How do I split a string on a delimiter in Bash?

Without setting the IFS

If you just have one colon you can do that:

a="foo:bar"
b=${a%:*}
c=${a##*:}

you will get:

b = foo
c = bar

ldap query for group members

The query should be:

(&(objectCategory=user)(memberOf=CN=Distribution Groups,OU=Mybusiness,DC=mydomain.local,DC=com))

You missed & and ()

How to add border radius on table row

You can only apply border-radius to td, not tr or table. I've gotten around this for rounded corner tables by using these styles:

table { border-collapse: separate; }
td { border: solid 1px #000; }
tr:first-child td:first-child { border-top-left-radius: 10px; }
tr:first-child td:last-child { border-top-right-radius: 10px; }
tr:last-child td:first-child { border-bottom-left-radius: 10px; }
tr:last-child td:last-child { border-bottom-right-radius: 10px; }

Be sure to provide all the vendor prefixes. Here's an example of it in action.

'LIKE ('%this%' OR '%that%') and something=else' not working

Break out the LIKE clauses into 2 separate statements, i.e.:

(fieldname1 LIKE '%this%' or fieldname1 LIKE '%that%' ) and something=else

Is ASCII code 7-bit or 8-bit?

ASCII was indeed originally conceived as a 7-bit code. This was done well before 8-bit bytes became ubiquitous, and even into the 1990s you could find software that assumed it could use the 8th bit of each byte of text for its own purposes ("not 8-bit clean"). Nowadays people think of it as an 8-bit coding in which bytes 0x80 through 0xFF have no defined meaning, but that's a retcon.

There are dozens of text encodings that make use of the 8th bit; they can be classified as ASCII-compatible or not, and fixed- or variable-width. ASCII-compatible means that regardless of context, single bytes with values from 0x00 through 0x7F encode the same characters that they would in ASCII. You don't want to have anything to do with a non-ASCII-compatible text encoding if you can possibly avoid it; naive programs expecting ASCII tend to misinterpret them in catastrophic, often security-breaking fashion. They are so deprecated nowadays that (for instance) HTML5 forbids their use on the public Web, with the unfortunate exception of UTF-16. I'm not going to talk about them any more.

A fixed-width encoding means what it sounds like: all characters are encoded using the same number of bytes. To be ASCII-compatible, a fixed-with encoding must encode all its characters using only one byte, so it can have no more than 256 characters. The most common such encoding nowadays is Windows-1252, an extension of ISO 8859-1.

There's only one variable-width ASCII-compatible encoding worth knowing about nowadays, but it's very important: UTF-8, which packs all of Unicode into an ASCII-compatible encoding. You really want to be using this if you can manage it.

As a final note, "ASCII" nowadays takes its practical definition from Unicode, not its original standard (ANSI X3.4-1968), because historically there were several dozen variations on the ASCII 127-character repertoire -- for instance, some of the punctuation might be replaced with accented letters to facilitate the transmission of French text. Nowadays all of those variations are obsolescent, and when people say "ASCII" they mean that the bytes with value 0x00 through 0x7F encode Unicode codepoints U+0000 through U+007F. This will probably only matter to you if you ever find yourself writing a technical standard.

If you're interested in the history of ASCII and the encodings that preceded it, start with the paper "The Evolution of Character Codes, 1874-1968" (samizdat copy at http://falsedoor.com/doc/ascii_evolution-of-character-codes.pdf) and then chase its references (many of which are not available online and may be hard to find even with access to a university library, I regret to say).

How to declare a static const char* in your header file?

The error is that you cannot initialize a static const char* within the class. You can only initialize integer variables there.

You need to declare the member variable in the class, and then initialize it outside the class:

// header file

class Foo {
    static const char *SOMETHING;
    // rest of class
};

// cpp file

const char *Foo::SOMETHING = "sommething";

If this seems annoying, think of it as being because the initialization can only appear in one translation unit. If it was in the class definition, that would usually be included by multiple files. Constant integers are a special case (which means the error message perhaps isn't as clear as it might be), and compilers can effectively replace uses of the variable with the integer value.

In contrast, a char* variable points to an actual object in memory, which is required to really exist, and it's the definition (including initialization) which makes the object exist. The "one definition rule" means you therefore don't want to put it in a header, because then all translation units including that header would contain the definition. They could not be linked together, even though the string contains the same characters in both, because under current C++ rules you've defined two different objects with the same name, and that's not legal. The fact that they happen to have the same characters in them doesn't make it legal.

Using @property versus getters and setters

In complex projects I prefer using read-only properties (or getters) with explicit setter function:

class MyClass(object):
...        
@property
def my_attr(self):
    ...

def set_my_attr(self, value):
    ...

In long living projects debugging and refactoring takes more time than writing the code itself. There are several downsides for using @property.setter that makes debugging even harder:

1) python allows creating new attributes for an existing object. This makes a following misprint very hard to track:

my_object.my_atttr = 4.

If your object is a complicated algorithm then you will spend quite some time trying to find out why it doesn't converge (notice an extra 't' in the line above)

2) setter sometimes might evolve to a complicated and slow method (e.g. hitting a database). It would be quite hard for another developer to figure out why the following function is very slow. He might spend a lot of time on profiling do_something() method, while my_object.my_attr = 4. is actually the cause of slowdown:

def slow_function(my_object):
    my_object.my_attr = 4.
    my_object.do_something()

How to style the menu items on an Android action bar

I did this way:

<style name="AppTheme" parent="Theme.AppCompat.Light.DarkActionBar">
    <item name="colorPrimary">@color/colorPrimary</item>
    <item name="colorPrimaryDark">@color/colorPrimaryDark</item>
    <item name="colorAccent">@color/colorAccent</item>
    <item name="actionMenuTextAppearance">@style/MenuTextAppearance</item>
    <item name="android:actionMenuTextAppearance">@style/MenuTextAppearance</item>
    <item name="actionMenuTextColor">@color/colorAccent</item>
</style>

<style name="MenuTextAppearance" >
    <item name="android:textAppearance">@android:style/TextAppearance.Large</item>
    <item name="android:textSize">20sp</item>
    <item name="android:textStyle">bold</item>
</style>

Highest Salary in each department

Use the below quesry:

select employee_name,salary,department_id from emp where salary in(select max(salary) from emp group by department_id);

Converting map to struct

Hashicorp's https://github.com/mitchellh/mapstructure library does this out of the box:

import "github.com/mitchellh/mapstructure"

mapstructure.Decode(myData, &result)

The second result parameter has to be an address of the struct.

'ssh-keygen' is not recognized as an internal or external command

for all windows os

cd C:\Program Files (x86)\Git\bin
ssh-keygen

How can I set NODE_ENV=production on Windows?

I wrote a module win-node-env with which you can run your command just like you would in *nix.

NODE_ENV=production node myapp/app.js

It works by creating a NODE_ENV.cmd that sets the NODE_ENV environment variable and spawns a child process with the rest of the command and its args.

Just install it (globally), and run your npm script commands, it should automatically make them work.

npm install -g win-node-env

String is immutable. What exactly is the meaning?

I think the following code clears the difference:

String A = new String("Venugopal");
String B = A;

A = A +"mitul";

System.out.println("A is " + A);
System.out.println("B is " + B);

StringBuffer SA = new StringBuffer("Venugopal");
StringBuffer SB = SA;

SA = SA.append("mitul");

System.out.println("SA is " + SA);
System.out.println("SB is " + SB);

How do you rename a MongoDB database?

NOTE: Hopefully this changed in the latest version.

You cannot copy data between a MongoDB 4.0 mongod instance (regardless of the FCV value) and a MongoDB 3.4 and earlier mongod instance. https://docs.mongodb.com/v4.0/reference/method/db.copyDatabase/

ALERT: Hey folks just be careful while copying the database, if you don't want to mess up the different collections under single database.

The following shows you how to rename

> show dbs;
testing
games
movies

To rename you use the following syntax

db.copyDatabase("old db name","new db name")

Example:

db.copyDatabase('testing','newTesting')

Now you can safely delete the old db by the following way

use testing;

db.dropDatabase(); //Here the db **testing** is deleted successfully

Now just think what happens if you try renaming the new database name with existing database name

Example:

db.copyDatabase('testing','movies'); 

So in this context all the collections (tables) of testing will be copied to movies database.

Image library for Python 3

If you are on Python3 you can also use the library PILasOPENCV which works in Python 2 and 3. Function api calls are the same as in PIL or pillow but internally it works with OpenCV and numpy to load, save and manipulate images. Have a look at https://github.com/bunkahle/PILasOPENCV or install it with pip install PILasOPENCV. Not all PIL functions have been simulated but the most common functions work.

Can't get ScriptManager.RegisterStartupScript in WebControl nested in UpdatePanel to work

I had an issue with Page.ClientScript.RegisterStartUpScript - I wasn't using an update panel, but the control was cached. This meant that I had to insert the script into a Literal (or could use a PlaceHolder) so when rendered from the cache the script is included.

A similar solution might work for you.

iOS Remote Debugging

Even I am looking for the same feature, and as of today, its yet to be implemented. I can think of two options however,

  1. I noticed that the behavior of Chrome and Safari are quite identical; Chrome even supports the Gyroscope and other related events which are supported by Safari. I am currently debugging my Web App by enabling the debug console on Safari (Through Settings->Safari)

  2. Also try Adobe Shadow, which allows remote debugging/inspection and Sync.

HTH.

check if a key exists in a bucket in s3 using boto3

The easiest way I found (and probably the most efficient) is this:

import boto3
from botocore.errorfactory import ClientError

s3 = boto3.client('s3')
try:
    s3.head_object(Bucket='bucket_name', Key='file_path')
except ClientError:
    # Not found
    pass

Oracle Installer:[INS-13001] Environment does not meet minimum requirements

its awful oracle installer:

[INS-13001]

I got it as I used MY_PC as NETBIOS name instead of MYPC (Underscore is bad for it..)

Can be an historical reason.. but message is obscure.

iPhone hide Navigation Bar only on first page

The currently accepted answer does not match the intended behavior described in the question. The question asks for the navigation bar to be hidden on the root view controller, but visible everywhere else, but the accepted answer hides the navigation bar on a particular view controller. What happens when another instance of the first view controller is pushed onto the stack? It will hide the navigation bar even though we are not looking at the root view controller.

Instead, @Chad M.'s strategy of using the UINavigationControllerDelegate is a good one, and here is a more complete solution. Steps:

  1. Subclass UINavigationController
  2. Implement the -navigationController:willShowViewController:animated method to show or hide the navigation bar based on whether it is showing the root view controller
  3. Override the initialization methods to set the UINavigationController subclass as its own delegate

Complete code for this solution can be found in this Gist. Here's the navigationController:willShowViewController:animated implementation:

- (void)navigationController:(UINavigationController *)navigationController willShowViewController:(UIViewController *)viewController animated:(BOOL)animated
{
    /* Hide navigation bar if root controller */
    if ([viewController isEqual:[self.viewControllers firstObject]]) {
        [self setNavigationBarHidden:YES animated:animated];
    } else {
        [self setNavigationBarHidden:NO animated:animated];
    }
}

Which MySQL data type to use for storing boolean values

If you use the BOOLEAN type, this is aliased to TINYINT(1). This is best if you want to use standardised SQL and don't mind that the field could contain an out of range value (basically anything that isn't 0 will be 'true').

ENUM('False', 'True') will let you use the strings in your SQL, and MySQL will store the field internally as an integer where 'False'=0 and 'True'=1 based on the order the Enum is specified.

In MySQL 5+ you can use a BIT(1) field to indicate a 1-bit numeric type. I don't believe this actually uses any less space in the storage but again allows you to constrain the possible values to 1 or 0.

All of the above will use approximately the same amount of storage, so it's best to pick the one you find easiest to work with.

How do you increase the max number of concurrent connections in Apache?

change the MaxClients directive. it is now on 256.

How to export a mysql database using Command Prompt?

I have installed my wamp server in D: drive so u have to go to the following path from ur command line->(and if u have installed ur wamp in c: drive then just replace the d: wtih c: here)

D:\>cd wamp
D:\wamp>cd bin
D:\wamp\bin>cd mysql
D:\wamp\bin\mysql>cd mysql5.5.8 (whatever ur verserion will be displayed here use keyboard Tab button and select the currently working mysql version on your server if you have more than one mysql versions)
D:\wamp\bin\mysql\mysql5.5.8>cd bin
D:\wamp\bin\mysql\mysql5.5.8\bin>mysqldump -u root -p password db_name > "d:\backupfile.sql"

here root is user of my phpmyadmin password is the password for phpmyadmin so if u haven't set any password for root just nothing type at that place, db_name is the database (for which database u r taking the backup) ,backupfile.sql is the file in which u want ur backup of ur database and u can also change the backup file location(d:\backupfile.sql) from to any other place on your computer

What is the difference between '@' and '=' in directive scope in AngularJS?

I created a little HTML file that contains Angular code demonstrating the differences between them:

<!DOCTYPE html>
<html>
  <head>
    <title>Angular</title>
    <script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.3.15/angular.min.js"></script>
  </head>
  <body ng-app="myApp">
    <div ng-controller="myCtrl as VM">
      <a my-dir
        attr1="VM.sayHi('Juan')" <!-- scope: "=" -->
        attr2="VM.sayHi('Juan')" <!-- scope: "@" -->
        attr3="VM.sayHi('Juan')" <!-- scope: "&" -->
      ></a>
    </div>
    <script>
    angular.module("myApp", [])
    .controller("myCtrl", [function(){
      var vm = this;
      vm.sayHi = function(name){
        return ("Hey there, " + name);
      }
    }])
    .directive("myDir", [function(){
      return {
        scope: {
          attr1: "=",
          attr2: "@",
          attr3: "&"
        },
        link: function(scope){
          console.log(scope.attr1);   // =, logs "Hey there, Juan"
          console.log(scope.attr2);   // @, logs "VM.sayHi('Juan')"
          console.log(scope.attr3);   // &, logs "function (a){return h(c,a)}"
          console.log(scope.attr3()); // &, logs "Hey there, Juan"
        }
      }
    }]);
    </script>
  </body>
</html>

Why when I transfer a file through SFTP, it takes longer than FTP?

Your results make sense. Since FTP operates over a non-encrypted channel it is faster than SFTP (which is subsystem on top of the SSH version 2 protocol). Also remember that SFTP is a packet based protocol unlike FTP which is command based.

Each packet in SFTP is encrypted before being written to the outgoing socket from the client and subsequently decrypted when received by the server. This of-course leads to slow transfer rates but very secure transfer. Using compression such as zlib with SFTP improves the transfer time but still it won't be anywhere near plain text FTP. Perhaps a better comparison is to compare SFTP with FTPS which both use encryption?

Speed for SFTP depends on the cipher used for encryption/decryption, the compression used e.g. zlib, packet sizes and buffer sizes used for the socket connection.

error: request for member '..' in '..' which is of non-class type

If you want to declare a new substance with no parameter (knowing that the object have default parameters) don't write

 type substance1();

but

 type substance;

Xampp localhost/dashboard

Here's what's actually happening localhost means that you want to open htdocs. First it will search for any file named index.php or index.html. If one of those exist it will open the file. If neither of those exist then it will open all folder/file inside htdocs directory which is what you want.

So, the simplest solution is to rename index.php or index.html to index2.php etc.

Are there dictionaries in php?

No, there are no dictionaries in php. The closest thing you have is an array. However, an array is different than a dictionary in that arrays have both an index and a key. Dictionaries only have keys and no index. What do I mean by that?

$array = array(
    "foo" => "bar",
    "bar" => "foo"
);

// as of PHP 5.4
$array = [
    "foo" => "bar",
    "bar" => "foo",
];

The following line is allowed with the above array but would give an error if it was a dictionary.

print $array[0]

Python has both arrays and dictionaries.

How to read file from relative path in Java project? java.io.File cannot find the path specified

While the answer provided by BalusC works for this case, it will break when the file path contains spaces because in a URL, these are being converted to %20 which is not a valid file name. If you construct the File object using a URI rather than a String, whitespaces will be handled correctly:

URL url = getClass().getResource("ListStopWords.txt");
File file = new File(url.toURI());

How to Lazy Load div background images

I've found this on the plugin's official site:

<div class="lazy" data-original="img/bmw_m1_hood.jpg" style="background-image: url('img/grey.gif'); width: 765px; height: 574px;"></div>

$("div.lazy").lazyload({
      effect : "fadeIn"
});

Source: http://www.appelsiini.net/projects/lazyload/enabled_background.html

How to export a Vagrant virtual machine to transfer it

You have two ways to do this, I'll call it dirty way and clean way:

1. The dirty way

Create a box from your current virtual environment, using vagrant package command:

http://docs.vagrantup.com/v2/cli/package.html

Then copy the box to the other pc, add it using vagrant box add and run it using vagrant up as usual.

Keep in mind that files in your working directory (the one with the Vagrantfile) are shared when the virtual machine boots, so you need to copy it to the other pc as well.

2. The clean way

Theoretically it should never be necessary to do export/import with Vagrant. If you have the foresight to use provisioning for configuring the virtual environment (chef, puppet, ansible), and a version control system like git for your working directory, copying an environment would be at this point simple as running:

git clone <your_repo>
vagrant up

Handling NULL values in Hive

I use below sql to exclude the null string and empty string lines.

select * from table where length(nvl(column1,0))>0

Because, the length of empty string is 0.

select length('');
+-----------+--+
| length()  |
+-----------+--+
| 0         |
+-----------+--+

What are the First and Second Level caches in (N)Hibernate?

There's a pretty good explanation of first level caching on the Streamline Logic blog.

Basically, first level caching happens on a per session basis where as second level caching can be shared across multiple sessions.

For each row in an R dataframe

you can do something for a list object,

data("mtcars")
rownames(mtcars)
data <- list(mtcars ,mtcars, mtcars, mtcars);data

out1 <- NULL 
for(i in seq_along(data)) { 
  out1[[i]] <- data[[i]][rownames(data[[i]]) != "Volvo 142E", ] } 
out1

Or a data frame,

data("mtcars")
df <- mtcars
out1 <- NULL 
for(i in 1:nrow(df)) {
  row <- rownames(df[i,])
  # do stuff with row
  out1 <- df[rownames(df) != "Volvo 142E",]
  
}
out1 

JOIN queries vs multiple queries

Will it be faster in terms of throughput? Probably. But it also potentially locks more database objects at a time (depending on your database and your schema) and thereby decreases concurrency. In my experience people are often mislead by the "fewer database round-trips" argument when in reality on most OLTP systems where the database is on the same LAN, the real bottleneck is rarely the network.

How to create a String with carriage returns?

Try append characters .append('\r').append('\n'); instead of String .append("\\r\\n");

Partial Dependency (Databases)

Partial dependence is solved for arriving to a relation in 2NF but 2NF is a "stepping stone" (C. Date) for solving any transitive dependency and arriving to a relation in 3NF (which is the operational target). However, the most interested thing on partial dependence is that it is a particular case of the own transitive dependency. This was demostrated by P. A. Berstein in 1976: IF {(x•y)?z but y?z} THEN {(x•y)?y & y?z}. The 3NF synthesizer algorithm of Berstein does not need doing distintions among these two type of relational defects.

Xcode process launch failed: Security

In iOS 9.2 they renamed the 'Profiles' to 'Device Management'

This is how you should do it now:

  1. Settings -> General -> Device Management
  2. Verify the app

TypeError: 'builtin_function_or_method' object is not subscriptable

Can't believe this thread was going on for so long. You would get this error if you got distracted and used [] instead of (), at least my case.

Pop is a method on the list data type, https://docs.python.org/2/tutorial/datastructures.html#more-on-lists

Therefore, you shouldn't be using pop as if it was a list itself, pop[0]. It's a method that takes an optional parameter representing an index, so as Tushar Palawat pointed out in one of the answers that didn't get approved, the correct adjustment which will fix the example above is:

listb.pop(0)

If you don't believe, run a sample such as:

if __name__ == '__main__':
  listb = ["-test"]
  if( listb[0] == "-test"):
    print(listb.pop(0))

Other adjustments would work as well, but it feels as they are abusing the Python language. This thread needs to get fixed, not to confuse users.

Addition, a.pop() removes and returns the last item in the list. As a result, a.pop()[0] will get the first character of that last element. It doesn't seem that is what the given code snippet is aiming to achieve.

Solr vs. ElasticSearch

Add an nested document in solr very complex and nested data search also very complex. but Elastic Search easy to add nested document and search

VC++ fatal error LNK1168: cannot open filename.exe for writing

Start your program as an administrator. The program can't rewrite your files cause your files are in a protected location on your hard drive.

Uncaught TypeError: undefined is not a function while using jQuery UI

use jQuery.noConflict()

var j = jQuery.noConflict();
j(document).ready(function(){
    j('#datetimepicker').datepicker();
})

Is an entity body allowed for an HTTP DELETE request?

In case anyone is running into this issue testing, No it is not universally supported.

I am currently testing with Sahi Pro and it is very apparent a http DELETE call strips any provided body data (a large list of id's to delete in bulk as per endpoint design).

I have been in contact with them several times as well as sent in three separate packages of scrips, images, logs for them to review and they still have not confirmed this. A failed patch, and a missed conference calls by their support later and I still haven't gotten a solid answer.

I am certain Sahi does not support this, and I would imagine many other tools follow suite.

Using % for host when creating a MySQL user

Going to provide a slightly different answer to those provided so far.

If you have a row for an anonymous user from localhost in your users table ''@'localhost' then this will be treated as more specific than your user with wildcard'd host 'user'@'%'. This is why it is necessary to also provide 'user'@'localhost'.

You can see this explained in more detail at the bottom of this page.

What is the best way to get the count/length/size of an iterator?

for Java 8 you could use,

public static int getIteratorSize(Iterator iterator){
        AtomicInteger count = new AtomicInteger(0);
        iterator.forEachRemaining(element -> {
            count.incrementAndGet();
        });
        return count.get();
    }

error_reporting(E_ALL) does not produce error

In your php.ini file check for display_errors. I think it is off.

<?php
error_reporting(E_ALL);
ini_set('display_errors', TRUE);
ini_set('display_startup_errors', TRUE);

Node.js: Python not found exception due to node-sass and node-gyp

I found the same issue with Node 12.19.0 and yarn 1.22.5 on Windows 10. I fixed the problem by installing latest stable python 64-bit with adding the path to Environment Variables during python installation. After python installation, I restarted my machine for env vars.

Call an angular function inside html

Yep, just add parenthesis (calling the function). Make sure the function is in scope and actually returns something.

<ul class="ui-listview ui-radiobutton" ng-repeat="meter in meters">
  <li class = "ui-divider">
    {{ meter.DESCRIPTION }}
    {{ htmlgeneration() }}
  </li>
</ul>

Creating a dictionary from a CSV file

You can also use numpy for this.

from numpy import loadtxt
key_value = loadtxt("filename.csv", delimiter=",")
mydict = { k:v for k,v in key_value }

How to change JDK version for an Eclipse project

Click on the Add Library button. It brings your screen to point to the Java location.

Select "Directory", button right besides JRE home and point to the installed folder location.

Even though you want to just 1.5 compiler project, you can achieve it by changing compiler settings in Eclipse instead of removing 1.6 JRE and add 1.5 JRE.

GOTO -->JAVA--Compiler---> and change compiler level to `1.5` instead of `1.6`

As davidfmatheson suggested,

Just be careful, especially if you're setting this up for a team of people to work on. If anyone uses anything that is new or changed in 1.6, it will compile, but not run in an environment with JRE 1.5.

Change project name on Android Studio

Just find the name " android:label="AppName" " from the Android Manifest . Just rename the label name (eg: "AppName" here) all such android:label in the AndroidManifest.xml . Just save it ! When you run the app you will see the new Name

Assign result of dynamic sql to variable

You should try this while getting SEQUENCE value in a variable from the dynamic table.

DECLARE @temp table (#temp varchar (MAX));
DECLARE @SeqID nvarchar(150);
DECLARE @Name varchar(150); 

SET @Name = (Select Name from table)
SET @SeqID = 'SELECT NEXT VALUE FOR '+ @Name + '_Sequence'
insert @temp exec (@SeqID)

SET @SeqID = (select * from @temp )
PRINT @SeqID

Result:

(1 row(s) affected)
 1

Why do I need 'b' to encode a string with Base64?

There is all you need:

expected bytes, not str

The leading b makes your string binary.

What version of Python do you use? 2.x or 3.x?

Edit: See http://docs.python.org/release/3.0.1/whatsnew/3.0.html#text-vs-data-instead-of-unicode-vs-8-bit for the gory details of strings in Python 3.x

Compare string with all values in list

In Python you may use the in operator. You can do stuff like this:

>>> "c" in "abc"
True

Taking this further, you can check for complex structures, like tuples:

>>> (2, 4, 8) in ((1, 2, 3), (2, 4, 8))
True

MySQL direct INSERT INTO with WHERE clause

The INSERT INTO Statement
The INSERT INTO statement is used to insert a new row in a table.
SQL INSERT INTO Syntax

It is possible to write the INSERT INTO statement in two forms.

The first form doesn't specify the column names where the data will be inserted, only their values:

INSERT INTO table_name
VALUES (value1, value2, value3,...)

The second form specifies both the column names and the values to be inserted:

INSERT INTO table_name (column1, column2, column3,...)
VALUES (value1, value2, value3,...)

How to check if a number is between two values?

I prefer to put the variable on the inside to give an extra hint that the code is validating my variable is between a range values

if (500 < size && size < 600) { doStuff(); }

What is the difference between char array and char pointer in C?

What is the difference between char array vs char pointer in C?

C99 N1256 draft

There are two different uses of character string literals:

  1. Initialize char[]:

    char c[] = "abc";      
    

    This is "more magic", and described at 6.7.8/14 "Initialization":

    An array of character type may be initialized by a character string literal, optionally enclosed in braces. Successive characters of the character string literal (including the terminating null character if there is room or if the array is of unknown size) initialize the elements of the array.

    So this is just a shortcut for:

    char c[] = {'a', 'b', 'c', '\0'};
    

    Like any other regular array, c can be modified.

  2. Everywhere else: it generates an:

    So when you write:

    char *c = "abc";
    

    This is similar to:

    /* __unnamed is magic because modifying it gives UB. */
    static char __unnamed[] = "abc";
    char *c = __unnamed;
    

    Note the implicit cast from char[] to char *, which is always legal.

    Then if you modify c[0], you also modify __unnamed, which is UB.

    This is documented at 6.4.5 "String literals":

    5 In translation phase 7, a byte or code of value zero is appended to each multibyte character sequence that results from a string literal or literals. The multibyte character sequence is then used to initialize an array of static storage duration and length just sufficient to contain the sequence. For character string literals, the array elements have type char, and are initialized with the individual bytes of the multibyte character sequence [...]

    6 It is unspecified whether these arrays are distinct provided their elements have the appropriate values. If the program attempts to modify such an array, the behavior is undefined.

6.7.8/32 "Initialization" gives a direct example:

EXAMPLE 8: The declaration

char s[] = "abc", t[3] = "abc";

defines "plain" char array objects s and t whose elements are initialized with character string literals.

This declaration is identical to

char s[] = { 'a', 'b', 'c', '\0' },
t[] = { 'a', 'b', 'c' };

The contents of the arrays are modifiable. On the other hand, the declaration

char *p = "abc";

defines p with type "pointer to char" and initializes it to point to an object with type "array of char" with length 4 whose elements are initialized with a character string literal. If an attempt is made to use p to modify the contents of the array, the behavior is undefined.

GCC 4.8 x86-64 ELF implementation

Program:

#include <stdio.h>

int main(void) {
    char *s = "abc";
    printf("%s\n", s);
    return 0;
}

Compile and decompile:

gcc -ggdb -std=c99 -c main.c
objdump -Sr main.o

Output contains:

 char *s = "abc";
8:  48 c7 45 f8 00 00 00    movq   $0x0,-0x8(%rbp)
f:  00 
        c: R_X86_64_32S .rodata

Conclusion: GCC stores char* it in .rodata section, not in .text.

If we do the same for char[]:

 char s[] = "abc";

we obtain:

17:   c7 45 f0 61 62 63 00    movl   $0x636261,-0x10(%rbp)

so it gets stored in the stack (relative to %rbp).

Note however that the default linker script puts .rodata and .text in the same segment, which has execute but no write permission. This can be observed with:

readelf -l a.out

which contains:

 Section to Segment mapping:
  Segment Sections...
   02     .text .rodata

PowerShell: Store Entire Text File Contents in Variable

To get the entire contents of a file:

$content = [IO.File]::ReadAllText(".\test.txt")

Number of lines:

([IO.File]::ReadAllLines(".\test.txt")).length

or

(gc .\test.ps1).length

Sort of hackish to include trailing empty line:

[io.file]::ReadAllText(".\desktop\git-python\test.ps1").split("`n").count

You need to install postgresql-server-dev-X.Y for building a server-side extension or libpq-dev for building a client-side application

I was using a virtual environment on Ubuntu 18.04, and since I only wanted to install it as a client, I only had to do:

sudo apt install libpq-dev
pip install psycopg2

And installed without problems. Of course, you can use the binary as other answers said, but I preferred this solution since it was stated in a requirements.txt file.

How to resolve "git pull,fatal: unable to access 'https://github.com...\': Empty reply from server"

I had tried most of the answers here but didn't manage to resolve the issue (on Windows 10).

What resolved the problem was simply to upgrade version from git version 2.8.1.windows.1 to the latest version git version 2.10.1.windows.1

Reading serial data in realtime in Python

A very good solution to this can be found here:

Here's a class that serves as a wrapper to a pyserial object. It allows you to read lines without 100% CPU. It does not contain any timeout logic. If a timeout occurs, self.s.read(i) returns an empty string and you might want to throw an exception to indicate the timeout.

It is also supposed to be fast according to the author:

The code below gives me 790 kB/sec while replacing the code with pyserial's readline method gives me just 170kB/sec.

class ReadLine:
    def __init__(self, s):
        self.buf = bytearray()
        self.s = s

    def readline(self):
        i = self.buf.find(b"\n")
        if i >= 0:
            r = self.buf[:i+1]
            self.buf = self.buf[i+1:]
            return r
        while True:
            i = max(1, min(2048, self.s.in_waiting))
            data = self.s.read(i)
            i = data.find(b"\n")
            if i >= 0:
                r = self.buf + data[:i+1]
                self.buf[0:] = data[i+1:]
                return r
            else:
                self.buf.extend(data)

ser = serial.Serial('COM7', 9600)
rl = ReadLine(ser)

while True:

    print(rl.readline())

What are .a and .so files?

They are used in the linking stage. .a files are statically linked, and .so files are sort-of linked, so that the library is needed whenever you run the exe.

You can find where they are stored by looking at any of the lib directories... /usr/lib and /lib have most of them, and there is also the LIBRARY_PATH environment variable.

How to extract code of .apk file which is not working?

Note: All of the following instructions apply universally (aka to all OSes) unless otherwise specified.


Prerequsites

You will need:

  • A working Java installation
  • A working terminal/command prompt
  • A computer
  • An APK file

Steps

Step 1: Changing the file extension of the APK file

  1. Change the file extension of the .apk file by either adding a .zip extension to the filename, or to change .apk to .zip.

    For example, com.example.apk becomes com.example.zip, or com.example.apk.zip. Note that on Windows and macOS, it may prompt you whether you are sure you want to change the file extension. Click OK or Add if you're using macOS:

macOS add extension confirm dialog

Step 2: Extracting Java files from APK

  1. Extract the renamed APK file in a specific folder. For example, let that folder be demofolder.

    • If it didn't work, try opening the file in another application such as WinZip or 7-Zip.

    • For macOS, you can try running unzip in Terminal (available at /Applications/Terminal.app), where it takes one or more arguments: the file to unzip + optional arguments. See man unzip for documentation and arguments.

  2. Download dex2jar (see all releases on GitHub) and extract that zip file in the same folder as stated in the previous point.

  3. Open command prompt (or a terminal) and change your current directory to the folder created in the previous point and type the command d2j-dex2jar.bat classes.dex and press enter. This will generate classes-dex2jar.jar file in the same folder.

    • macOS/Linux users: Replace d2j-dex2jar.bat with d2j-dex2jar.sh. In other words, run d2j-jar2dex.sh classes.dex in the terminal and press enter.
  4. Download Java Decompiler (see all releases on Github) and extract it and start (aka double click) the executable/application.

  5. From the JD-GUI window, either drag and drop the generated classes-dex2jar.jar file into it, or go to File > Open File... and browse for the jar.

  6. Next, in the menu, go to File > Save All Sources (Windows: Ctrl+Alt+S, macOS: ?+?+S). This should open a dialog asking you where to save a zip file named `classes-dex2jar.jar.src.zip" consisting of all packages and java files. (You can rename the zip file to be saved)

  7. Extract that zip file (classes-dex2jar.jar.src.zip) and you should get all java files of the application.

Step 3: Getting xml files from APK

  • For more info, see the apktool website for installation instructions and more
  • Windows:

    1. Download the wrapper script (optional) and the apktool jar (required) and place it in the same folder (for example, myxmlfolder).
    2. Change your current directory to the myxmlfolder folder and rename the apktool jar file to apktool.jar.
    3. Place the .apk file in the same folder (i.e myxmlfolder).
    4. Open the command prompt (or terminal) and change your current directory to the folder where apktool is stored (in this case, myxmlfolder). Next, type the command apktool if framework-res.apk.

      What we're doing here is that we are installing a framework. For more info, see the docs.

    5. The above command should result in "Framework installed ..."
    6. In the command prompt, type the command apktool d filename.apk (where filename is the name of apk file). This should decode the file. For more info, see the docs.

      This should result in a folder filename.out being outputted, where filename is the original name of the apk file without the .apk file extension. In this folder are all the XML files such as layout, drawables etc.

Source: How to get source code from APK file - Comptech Blogspot

PHP Warning Permission denied (13) on session_start()

You don't appear to have write permission to the /tmp directory on your server. This is a bit weird, but you can work around it. Before the call to session_start() put in a call to session_save_path() and give it the name of a directory writable by the server. Details are here.

How to read and write xml files?

Here is a quick DOM example that shows how to read and write a simple xml file with its dtd:

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<!DOCTYPE roles SYSTEM "roles.dtd">
<roles>
    <role1>User</role1>
    <role2>Author</role2>
    <role3>Admin</role3>
    <role4/>
</roles>

and the dtd:

<?xml version="1.0" encoding="UTF-8"?>
<!ELEMENT roles (role1,role2,role3,role4)>
<!ELEMENT role1 (#PCDATA)>
<!ELEMENT role2 (#PCDATA)>
<!ELEMENT role3 (#PCDATA)>
<!ELEMENT role4 (#PCDATA)>

First import these:

import javax.xml.parsers.*;
import javax.xml.transform.*;
import javax.xml.transform.dom.*;
import javax.xml.transform.stream.*;
import org.xml.sax.*;
import org.w3c.dom.*;

Here are a few variables you will need:

private String role1 = null;
private String role2 = null;
private String role3 = null;
private String role4 = null;
private ArrayList<String> rolev;

Here is a reader (String xml is the name of your xml file):

public boolean readXML(String xml) {
        rolev = new ArrayList<String>();
        Document dom;
        // Make an  instance of the DocumentBuilderFactory
        DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
        try {
            // use the factory to take an instance of the document builder
            DocumentBuilder db = dbf.newDocumentBuilder();
            // parse using the builder to get the DOM mapping of the    
            // XML file
            dom = db.parse(xml);

            Element doc = dom.getDocumentElement();

            role1 = getTextValue(role1, doc, "role1");
            if (role1 != null) {
                if (!role1.isEmpty())
                    rolev.add(role1);
            }
            role2 = getTextValue(role2, doc, "role2");
            if (role2 != null) {
                if (!role2.isEmpty())
                    rolev.add(role2);
            }
            role3 = getTextValue(role3, doc, "role3");
            if (role3 != null) {
                if (!role3.isEmpty())
                    rolev.add(role3);
            }
            role4 = getTextValue(role4, doc, "role4");
            if ( role4 != null) {
                if (!role4.isEmpty())
                    rolev.add(role4);
            }
            return true;

        } catch (ParserConfigurationException pce) {
            System.out.println(pce.getMessage());
        } catch (SAXException se) {
            System.out.println(se.getMessage());
        } catch (IOException ioe) {
            System.err.println(ioe.getMessage());
        }

        return false;
    }

And here a writer:

public void saveToXML(String xml) {
    Document dom;
    Element e = null;

    // instance of a DocumentBuilderFactory
    DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
    try {
        // use factory to get an instance of document builder
        DocumentBuilder db = dbf.newDocumentBuilder();
        // create instance of DOM
        dom = db.newDocument();

        // create the root element
        Element rootEle = dom.createElement("roles");

        // create data elements and place them under root
        e = dom.createElement("role1");
        e.appendChild(dom.createTextNode(role1));
        rootEle.appendChild(e);

        e = dom.createElement("role2");
        e.appendChild(dom.createTextNode(role2));
        rootEle.appendChild(e);

        e = dom.createElement("role3");
        e.appendChild(dom.createTextNode(role3));
        rootEle.appendChild(e);

        e = dom.createElement("role4");
        e.appendChild(dom.createTextNode(role4));
        rootEle.appendChild(e);

        dom.appendChild(rootEle);

        try {
            Transformer tr = TransformerFactory.newInstance().newTransformer();
            tr.setOutputProperty(OutputKeys.INDENT, "yes");
            tr.setOutputProperty(OutputKeys.METHOD, "xml");
            tr.setOutputProperty(OutputKeys.ENCODING, "UTF-8");
            tr.setOutputProperty(OutputKeys.DOCTYPE_SYSTEM, "roles.dtd");
            tr.setOutputProperty("{http://xml.apache.org/xslt}indent-amount", "4");

            // send DOM to file
            tr.transform(new DOMSource(dom), 
                                 new StreamResult(new FileOutputStream(xml)));

        } catch (TransformerException te) {
            System.out.println(te.getMessage());
        } catch (IOException ioe) {
            System.out.println(ioe.getMessage());
        }
    } catch (ParserConfigurationException pce) {
        System.out.println("UsersXML: Error trying to instantiate DocumentBuilder " + pce);
    }
}

getTextValue is here:

private String getTextValue(String def, Element doc, String tag) {
    String value = def;
    NodeList nl;
    nl = doc.getElementsByTagName(tag);
    if (nl.getLength() > 0 && nl.item(0).hasChildNodes()) {
        value = nl.item(0).getFirstChild().getNodeValue();
    }
    return value;
}

Add a few accessors and mutators and you are done!

Mysql: Select rows from a table that are not in another

Try:

SELECT * FROM table1
    LEFT OUTER JOIN table2
    ON table1.FirstName = table2.FirstName and table1.LastName=table2.LastName
    WHERE table2.BirthDate IS NULL

ipynb import another ipynb file

Run

!pip install ipynb

and then import the other notebook as

from ipynb.fs.full.<notebook_name> import *

or

from ipynb.fs.full.<notebook_name> import <function_name>

Make sure that all the notebooks are in the same directory.

Edit 1: You can see the official documentation here - https://ipynb.readthedocs.io/en/stable/

Also, if you would like to import only class & function definitions from a notebook (and not the top level statements), you can use ipynb.fs.defs instead of ipynb.fs.full. Full uppercase variable assignment will get evaluated as well.

How to capture Curl output to a file?

There are several options to make curl output to a file

 # saves it to myfile.txt
curl http://www.example.com/data.txt -o myfile.txt

# The #1 will get substituted with the url, so the filename contains the url
curl http://www.example.com/data.txt -o "file_#1.txt" 

# saves to data.txt, the filename extracted from the URL
curl http://www.example.com/data.txt -O 

# saves to filename determined by the Content-Disposition header sent by the server.
curl http://www.example.com/data.txt -O -J 

How to use jQuery to show/hide divs based on radio button selection?

<script type="text/javascript">
$(function() {
    $("[name=toggler]").click(function(){
            $('.toHide').hide();
            $("#blk-"+$(this).val()).show('slow');
    });
 });
</script>
</head>
<body>
<label><input id="rdb1" type="radio" name="toggler" value="1" />Book</label>
<label><input id="rdb2" type="radio" name="toggler" value="2" />Non-Book</label>

<div id="blk-1" class="toHide" style="display:none">

    <form action="success1.html">

        Name1:<input type="text" name="name">
             <input type="submit" name="submit">

    </form>

</div>
<div id="blk-2" class="toHide" style="display:none">

    <form action="success1.html">

        Name2:<input type="text" name="name">
             <input type="submit" name="submit">

    </form>
</div>

How can I check if a key exists in a dictionary?

If you want to retrieve the key's value if it exists, you can also use

try:
    value = a[key]
except KeyError:
    # Key is not present
    pass

If you want to retrieve a default value when the key does not exist, use value = a.get(key, default_value). If you want to set the default value at the same time in case the key does not exist, use value = a.setdefault(key, default_value).

Check variable equality against a list of values

var a = [1,2,3];

if ( a.indexOf( 1 ) !== -1 ) { }

Note that indexOf is not in the core ECMAScript. You'll need to have a snippet for IE and possibly other browsers that dont support Array.prototype.indexOf.

if (!Array.prototype.indexOf)
{
  Array.prototype.indexOf = function(searchElement /*, fromIndex */)
  {
    "use strict";

    if (this === void 0 || this === null)
      throw new TypeError();

    var t = Object(this);
    var len = t.length >>> 0;
    if (len === 0)
      return -1;

    var n = 0;
    if (arguments.length > 0)
    {
      n = Number(arguments[1]);
      if (n !== n)
        n = 0;
      else if (n !== 0 && n !== (1 / 0) && n !== -(1 / 0))
        n = (n > 0 || -1) * Math.floor(Math.abs(n));
    }

    if (n >= len)
      return -1;

    var k = n >= 0
          ? n
          : Math.max(len - Math.abs(n), 0);

    for (; k < len; k++)
    {
      if (k in t && t[k] === searchElement)
        return k;
    }
    return -1;
  };
}

Push to GitHub without a password using ssh-key

Additionally for gists, it seems you must leave out the username

git remote set-url origin [email protected]:<Project code>

What is the optimal algorithm for the game 2048?

I'm the author of the AI program that others have mentioned in this thread. You can view the AI in action or read the source.

Currently, the program achieves about a 90% win rate running in javascript in the browser on my laptop given about 100 milliseconds of thinking time per move, so while not perfect (yet!) it performs pretty well.

Since the game is a discrete state space, perfect information, turn-based game like chess and checkers, I used the same methods that have been proven to work on those games, namely minimax search with alpha-beta pruning. Since there is already a lot of info on that algorithm out there, I'll just talk about the two main heuristics that I use in the static evaluation function and which formalize many of the intuitions that other people have expressed here.

Monotonicity

This heuristic tries to ensure that the values of the tiles are all either increasing or decreasing along both the left/right and up/down directions. This heuristic alone captures the intuition that many others have mentioned, that higher valued tiles should be clustered in a corner. It will typically prevent smaller valued tiles from getting orphaned and will keep the board very organized, with smaller tiles cascading in and filling up into the larger tiles.

Here's a screenshot of a perfectly monotonic grid. I obtained this by running the algorithm with the eval function set to disregard the other heuristics and only consider monotonicity.

A perfectly monotonic 2048 board

Smoothness

The above heuristic alone tends to create structures in which adjacent tiles are decreasing in value, but of course in order to merge, adjacent tiles need to be the same value. Therefore, the smoothness heuristic just measures the value difference between neighboring tiles, trying to minimize this count.

A commenter on Hacker News gave an interesting formalization of this idea in terms of graph theory.

Here's a screenshot of a perfectly smooth grid, courtesy of this excellent parody fork.

A perfectly smooth 2048 board

Free Tiles

And finally, there is a penalty for having too few free tiles, since options can quickly run out when the game board gets too cramped.

And that's it! Searching through the game space while optimizing these criteria yields remarkably good performance. One advantage to using a generalized approach like this rather than an explicitly coded move strategy is that the algorithm can often find interesting and unexpected solutions. If you watch it run, it will often make surprising but effective moves, like suddenly switching which wall or corner it's building up against.

Edit:

Here's a demonstration of the power of this approach. I uncapped the tile values (so it kept going after reaching 2048) and here is the best result after eight trials.

4096

Yes, that's a 4096 alongside a 2048. =) That means it achieved the elusive 2048 tile three times on the same board.

Shell script to delete directories older than n days

OR

rm -rf `find /path/to/base/dir/* -type d -mtime +10`

Updated, faster version of it:

find /path/to/base/dir/* -mtime +10 -print0 | xargs -0 rm -f

download and install visual studio 2008

Try this one: http://www.asp.net/downloads/essential This has web developer and VS2008 express

Netbeans 8.0.2 The module has not been deployed

the solution to this problem differs because each time you deploy the application will give you the same sentence or the problem is different, so you should see the tomcat server log for the exact problem.

HTML not loading CSS file

This may be a 'special' case but was fiddling with this piece of code:

ForceType application/x-httpd-php SetHandler application/x-httpd-php

As a quick test for extentionless file handling, when a similar problem occurred.

Some but not all php files thereafter treated the css files as php and thus succesfully loaded the css but not handled it as css, thus zero rules were executed when checking f12 style editor.

Perhaps something similar might occur to any-one else here and this tidbit might help.

How to get the size of the current screen in WPF?

This will give you the current screen based on the top left of the window just call this.CurrentScreen() to get info on the current screen.

using System.Windows;
using System.Windows.Forms;

namespace Common.Helpers
{
    public static class WindowHelpers
     {
        public static Screen CurrentScreen(this Window window)
         {
             return Screen.FromPoint(new System.Drawing.Point((int)window.Left,(int)window.Top));
         }
     }
}

Differences between cookies and sessions?

Google JSESSIONID. This will explain how the Servlet API initially uses URL re-writing and then, if cookies are enabled, cookies to manage sessions.

HTTP is stateless so the client browser must send the id of its session to the server with each request. The server, through whatever means, uses this id to retrieve any data for that session making it available for the lifetime of the request.

Axios Delete request with body and headers?

axios.delete is passed a url and an optional configuration.

axios.delete(url[, config])

The fields available to the configuration can include the headers.

This makes it so that the API call can be written as:

const headers = {
  'Authorization': 'Bearer paperboy'
}
const data = {
  foo: 'bar'
}

axios.delete('https://foo.svc/resource', {headers, data})

How to set aliases in the Git Bash for Windows?

  • Go to: C:\Users\ [youruserdirectory] \bash_profile

  • In your bash_profile file type - alias desk='cd " [DIRECTORY LOCATION] "'

  • Refresh your User directory where the bash_profile file exists then reopen your CMD or Git Bash window

Type in desk to see if you get to the Desktop location or the location you want in the "DIRECTORY LOCATION" area above

Note: [ desk ] can be what ever name that you choose and should get you to the location you want to get to when typed in the CMD window.

jquery AJAX and json format

You aren't actually sending JSON. You are passing an object as the data, but you need to stringify the object and pass the string instead.

Your dataType: "json" only tells jQuery that you want it to parse the returned JSON, it does not mean that jQuery will automatically stringify your request data.

Change to:

$.ajax({
        type: "POST",
        url: hb_base_url + "consumer",
        contentType: "application/json",
        dataType: "json",
        data: JSON.stringify({
            first_name: $("#namec").val(),
            last_name: $("#surnamec").val(),
            email: $("#emailc").val(),
            mobile: $("#numberc").val(),
            password: $("#passwordc").val()
        }),
        success: function(response) {
            console.log(response);
        },
        error: function(response) {
            console.log(response);
        }
});

Undefined reference to pthread_create in Linux

Sometimes, if you use multiple library, check the library dependency. (e.g. -lpthread -lSDL... <==> ... -lSDL -lpthread)

Find a private field with Reflection?

You can do it just like with a property:

FieldInfo fi = typeof(Foo).GetField("_bar", BindingFlags.NonPublic | BindingFlags.Instance);
if (fi.GetCustomAttributes(typeof(SomeAttribute)) != null)
    ...

Calling a JavaScript function named in a variable

This is kinda ugly, but its the first thing that popped in my head. This also should allow you to pass in arguments:

eval('var myfunc = ' + variable);  myfunc(args, ...);

If you don't need to pass in arguments this might be simpler.

eval(variable + '();');

Standard dry-code warning applies.

How to do a case sensitive search in WHERE clause (I'm using SQL Server)?

Can be done via changing the Collation. By default it is case insensitive.

Excerpt from the link:

SELECT 1
FROM dbo.Customers
WHERE   CustID = @CustID COLLATE SQL_Latin1_General_CP1_CS_AS
    AND CustPassword = @CustPassword COLLATE SQL_Latin1_General_CP1_CS_AS

Or, change the columns to be case sensitive.

JQuery get data from JSON array

I think you need something like:

var text= data.response.venue.tips.groups[0].items[1].text;

How to do an update + join in PostgreSQL?

For those actually wanting to do a JOIN you can also use:

UPDATE a
SET price = b_alias.unit_price
FROM      a AS a_alias
LEFT JOIN b AS b_alias ON a_alias.b_fk = b_alias.id
WHERE a_alias.unit_name LIKE 'some_value' 
AND a.id = a_alias.id;

You can use the a_alias in the SET section on the right of the equals sign if needed. The fields on the left of the equals sign don't require a table reference as they are deemed to be from the original "a" table.

Vertical dividers on horizontal UL menu

This can also be done via CSS:pseudo-classes. Support isn't quite as wide and the answer above gives you the same result, but it's pure CSS-y =)

.ULHMenu li { border-left: solid 2px black; }
.ULHMenu li:first-child { border: 0px; }

OR:

.ULHMenu li { border-right: solid 2px black; }
.ULHMenu li:last-child { border: 0px; }

See: http://www.quirksmode.org/css/firstchild.html
Or: http://www.w3schools.com/cssref/sel_firstchild.asp

Laravel 5: Display HTML with Blade

There is another way. If object purpose is to render html you can implement \Illuminate\Contracts\Support\Htmlable contract that has toHtml() method.

Then you can render that object from blade like this: {{ $someObject }} (note, no need for {!! !!} syntax).

Also if you want to return html property and you know it will be html, use \Illuminate\Support\HtmlString class like this:

public function getProductDescription()
{
    return new HtmlString($this->description);
}

and then use it like {{ $product->getProductDescription() }}.

Of course be responsible when directly rendering raw html on page.

Adding Jar files to IntellijIdea classpath

On the Mac version I was getting the error when trying to run JSON-Clojure.json.clj, which is the script to export a database table to JSON. To get it to work I had to download the latest Clojure JAR from http://clojure.org/ and then right-click on PHPStorm app in the Finder and "Show Package Contents". Then go to Contents in there. Then open the lib folder, and see a bunch of .jar files. Copy the clojure-1.8.0.jar file from the unzipped archive I downloaded from clojure.org into the aforementioned lib folder inside the PHPStorm.app/Contents/lib. Restart the app. Now it freaking works.

EDIT: You also have to put the JSR-223 script engine into PHPStorm.app/Contents/lib. It can be built from https://github.com/ato/clojure-jsr223 or downloaded from https://www.dropbox.com/s/jg7s0c41t5ceu7o/clojure-jsr223-1.5.1.jar?dl=0 .

React eslint error missing in props validation

Issue: 'id1' is missing in props validation, eslintreact/prop-types

<div id={props.id1} >
    ...
</div>

Below solution worked, in a function component:

let { id1 } = props;

<div id={id1} >
    ...
</div>

Hope that helps.

"Javac" doesn't work correctly on Windows 10

now i got it finally! make sure that there are no spaces before and after the path and put the semi-colon on both sides without spaces

from list of integers, get number closest to a given value

Iterate over the list and compare the current closest number with abs(currentNumber - myNumber):

def takeClosest(myList, myNumber):
    closest = myList[0]
    for i in range(1, len(myList)):
        if abs(i - myNumber) < closest:
            closest = i
    return closest

How do I update a formula with Homebrew?

You will first need to update the local formulas by doing

brew update

and then upgrade the package by doing

brew upgrade formula-name

An example would be if i wanted to upgrade mongodb, i would do something like this, assuming mongodb was already installed :

brew update && brew upgrade mongodb && brew cleanup mongodb

Displaying standard DataTables in MVC

This is not "wrong" at all, it's just not what the cool guys typically do with MVC. As an aside, I wish some of the early demos of ASP.NET MVC didn't try to cram in Linq-to-Sql at the same time. It's pretty awesome and well suited for MVC, sure, but it's not required. There is nothing about MVC that prevents you from using ADO.NET. For example:

Controller action:

public ActionResult Index()
{
    ViewData["Message"] = "Welcome to ASP.NET MVC!";

    DataTable dt = new DataTable("MyTable");
    dt.Columns.Add(new DataColumn("Col1", typeof(string)));
    dt.Columns.Add(new DataColumn("Col2", typeof(string)));
    dt.Columns.Add(new DataColumn("Col3", typeof(string)));

    for (int i = 0; i < 3; i++)
    {
        DataRow row = dt.NewRow();
        row["Col1"] = "col 1, row " + i;
        row["Col2"] = "col 2, row " + i;
        row["Col3"] = "col 3, row " + i;
        dt.Rows.Add(row);
    }

    return View(dt); //passing the DataTable as my Model
}

View: (w/ Model strongly typed as System.Data.DataTable)

<table border="1">
    <thead>
        <tr>
            <%foreach (System.Data.DataColumn col in Model.Columns) { %>
                <th><%=col.Caption %></th>
            <%} %>
        </tr>
    </thead>
    <tbody>
    <% foreach(System.Data.DataRow row in Model.Rows) { %>
        <tr>
            <% foreach (var cell in row.ItemArray) {%>
                <td><%=cell.ToString() %></td>
            <%} %>
        </tr>
    <%} %>         
    </tbody>
</table>

Now, I'm violating a whole lot of principles and "best-practices" of ASP.NET MVC here, so please understand this is just a simple demonstration. The code creating the DataTable should reside somewhere outside of the controller, and the code in the View might be better isolated to a partial, or html helper, to name a few ways you should do things.

You absolutely are supposed to pass objects to the View, if the view is supposed to present them. (Separation of concerns dictates the view shouldn't be responsible for creating them.) In this case I passed the DataTable as the actual view Model, but you could just as well have put it in ViewData collection. Alternatively you might make a specific IndexViewModel class that contains the DataTable and other objects, such as the welcome message.

I hope this helps!

Get current url in Angular

other.component.ts

So final correct solution is :

import { Component, OnInit } from '@angular/core';
import { Location } from '@angular/common';
import { Router } from '@angular/router'; 

/* 'router' it must be in small case */

    @Component({
      selector: 'app-other',
      templateUrl: './other.component.html',
      styleUrls: ['./other.component.css']
    })

    export class OtherComponent implements OnInit {

        public href: string = "";
        url: string = "asdf";

        constructor(private router : Router) {} // make variable private so that it would be accessible through out the component

        ngOnInit() {
            this.href = this.router.url;
            console.log(this.router.url);
        }
    }

Simulating Key Press C#

You can use the Win32 API FindWindow or FindWindowEx to find the window handle of the open browser and then just call SendMessage with WM_KEYDOWN. Typically it's easiest just to pass the window caption to FindWindowEx and have it find the associated window handle for you.

If you are starting the browser process yourself via a Process process object then you can use process.MainWindowHandle instead of calling FindWindowEx.

Spy++ is a very useful tool when you want to start working with other windows. It basically allows you to learn another program's hierarchy of UI elements. You can also monitor all of the messages that go into the window you're monitoring. I have more info in this thread.

The F5 keystroke has this virtual key code:

const int VK_F5 = 0x74;

The p/invoke signature for FindWindowEx in C# is:

[DllImport("user32.dll", SetLastError = true)]
static extern IntPtr FindWindowEx(IntPtr hwndParent, IntPtr hwndChildAfter, string lpszClass, string lpszWindow);

You can p/invoke (bring in) the Win32 API SendMessage like this:

[DllImport("user32.dll", CharSet = CharSet.Auto)]
static extern IntPtr SendMessage(IntPtr hWnd, UInt32 Msg, IntPtr wParam, IntPtr lParam);

So to recap, you call FindWindowEx directly from your C# code after having the above code somewhere inside your class. FindWindowEx will return a window handle. Then once you have the window handle, you can send any keystroke(s) to the window, or call many other Win32 API calls on the window handle. Or even find a child window by using another call to FindWindowEx. For example you could select the edit control of the browser even and then change it's text.

If all else goes wrong and you think you're sending the right key to the window, you can use spy++ to see what messages are sent to the window when you manually set focus to the browser and manually press F5.

How to access parameters in a Parameterized Build?

Use double quotes instead of single quotes

e.g. echo "$foo" as opposed to echo '$foo'

If you configured your pipeline to accept parameters using the Build with Parameters option, those parameters are accessible as Groovy variables of the same name. See Here.

You can drop the semicolon (;), drop the parentheses (( and )), and use single quotes (') instead of double (") if you do not need to perform variable substitutions. See Here. This clued me into my problem, though I've found that only the double (") is required to make it work.

Bootstrap Navbar toggle button not working

Wasted several hours only to realize that viewport meta was missing from my code. Adding here just in case some one else misses it out.

As soon as I added this, the toggle started working fine.

<meta name="viewport" content="width=device-width, initial-scale=1">

How to create a GUID/UUID using iOS

Reviewing the Apple Developer documentation I found the CFUUID object is available on the iPhone OS 2.0 and later.

No signing certificate "iOS Distribution" found

Our solution was to run

fastlane match

as I forgot we setup a Matchfile.

bash shell nested for loop

One one line (semi-colons necessary):

for i in 0 1 2 3 4 5 6 7 8 9; do for j in 0 1 2 3 4 5 6 7 8 9; do echo "$i$j"; done; done

Formatted for legibility (no semi-colons needed):

for i in 0 1 2 3 4 5 6 7 8 9
do
    for j in 0 1 2 3 4 5 6 7 8 9
    do 
        echo "$i$j"
    done
done

There are different views on how the shell code should be laid out over multiple lines; that's about what I normally use, unless I put the next operation on the same line as the do (saving two lines here).

XPath - Selecting elements that equal a value

Try

//*[text()='qwerty'] because . is your current element

MySQL config file location - redhat linux server

Default options are read from the following files in the given order:

/etc/mysql/my.cnf 
/etc/my.cnf 
~/.my.cnf 

How to exclude rows that don't join with another table?

Another solution is:

SELECT * FROM TABLE1 WHERE id NOT IN (SELECT id FROM TABLE2)

How to select an element by classname using jqLite?

Essentially, and as-noted by @kevin-b:

// find('#id')
angular.element(document.querySelector('#id'))

//find('.classname'), assumes you already have the starting elem to search from
angular.element(elem.querySelector('.classname'))

Note: If you're looking to do this from your controllers you may want to have a look at the "Using Controllers Correctly" section in the developers guide and refactor your presentation logic into appropriate directives (such as <a2b ...>).

Should you use rgba(0, 0, 0, 0) or rgba(255, 255, 255, 0) for transparency in CSS?

There are two ways of storing a color with alpha. The first is exactly as you see it, with each component as-is. The second is to use pre-multiplied alpha, where the color values are multiplied by the alpha after converting it to the range 0.0-1.0; this is done to make compositing easier. Ordinarily you shouldn't notice or care which way is implemented by any particular engine, but there are corner cases where you might, for example if you tried to increase the opacity of the color. If you use rgba(0, 0, 0, 0) you are less likely to to see a difference between the two approaches.

Zero an array in C code

Note: You can use memset with any character.

Example:

int arr[20];
memset(arr, 'A', sizeof(arr));

Also could be partially filled

int arr[20];
memset(&arr[5], 0, 10);

But be carefull. It is not limited for the array size, you could easily cause severe damage to your program doing something like this:

int arr[20];
memset(arr, 0, 200);

It is going to work (under windows) and zero memory after your array. It might cause damage to other variables values.

Removing all unused references from a project in Visual Studio projects

All you need is stone and bare knuckle then you can do it like a caveman.

  1. Remove unused namespaces (for each class)
  2. Run Debug build
  3. Copy your executable and remaining namespace references to new location
  4. Run the executable
  5. Missing Reference DLL error will occur
  6. Copy required DLL from Debug folder
  7. Repeat 4-6
  8. Gu Gu Ga Ga?
  9. Throw your stone

You can also rely on your build tools to let you know which reference is still required. It's the era of VS 2017, caveman still survived.

Print range of numbers on same line

Another single-line Python 3 option but with explicit separator:

print(*range(1,11), sep=' ')

How to concatenate strings with padding in sqlite

The || operator is "concatenate" - it joins together the two strings of its operands.

From http://www.sqlite.org/lang_expr.html

For padding, the seemingly-cheater way I've used is to start with your target string, say '0000', concatenate '0000423', then substr(result, -4, 4) for '0423'.

Update: Looks like there is no native implementation of "lpad" or "rpad" in SQLite, but you can follow along (basically what I proposed) here: http://verysimple.com/2010/01/12/sqlite-lpad-rpad-function/

-- the statement below is almost the same as
-- select lpad(mycolumn,'0',10) from mytable

select substr('0000000000' || mycolumn, -10, 10) from mytable

-- the statement below is almost the same as
-- select rpad(mycolumn,'0',10) from mytable

select substr(mycolumn || '0000000000', 1, 10) from mytable

Here's how it looks:

SELECT col1 || '-' || substr('00'||col2, -2, 2) || '-' || substr('0000'||col3, -4, 4)

it yields

"A-01-0001"
"A-01-0002"
"A-12-0002"
"C-13-0002"
"B-11-0002"

Android Facebook style slide

I think facebook app is not written in native code (by native code I mean, using layouts in Android) but they have used webview for it and have used some javascript ui libraries like sencha. It can be easily achieved using sencha framework.

enter image description here

How do I pretty-print existing JSON data with Java?

I think for pretty-printing something, it's very helpful to know its structure.

To get the structure you have to parse it. Because of this, I don't think it gets much easier than first parsing the JSON string you have and then using the pretty-printing method toString mentioned in the comments above.

Of course you can do similar with any JSON library you like.

"google is not defined" when using Google Maps V3 in Firefox remotely

Add the type for the script

<script src="https://maps.googleapis.com/maps/api/js" type="text/javascript"></script>

So the important part is the type text/javascript.

Could not complete the operation due to error 80020101. IE

I dont know why but it worked for me. If you have comments like

//Comment

Then it gives this error. To fix this do

/*Comment*/

Doesn't make sense but it worked for me.

C# How can I check if a URL exists/is valid?

i have a more simple way to determine weather a url is valid.

if (Uri.IsWellFormedUriString(uriString, UriKind.RelativeOrAbsolute))
{
   //...
}

"Could not find Developer Disk Image"

Older XCode version has no developer disk image for newer iOS version. If you don't want upgrade XCode you can find ready developer disk images for latest versions in this answer: https://stackoverflow.com/a/39865199/286361

C-like structures in Python

The following solution to a struct is inspired by the namedtuple implementation and some of the previous answers. However, unlike the namedtuple it is mutable, in it's values, but like the c-style struct immutable in the names/attributes, which a normal class or dict isn't.

_class_template = """\
class {typename}:
def __init__(self, *args, **kwargs):
    fields = {field_names!r}

    for x in fields:
        setattr(self, x, None)            

    for name, value in zip(fields, args):
        setattr(self, name, value)

    for name, value in kwargs.items():
        setattr(self, name, value)            

def __repr__(self):
    return str(vars(self))

def __setattr__(self, name, value):
    if name not in {field_names!r}:
        raise KeyError("invalid name: %s" % name)
    object.__setattr__(self, name, value)            
"""

def struct(typename, field_names):

    class_definition = _class_template.format(
        typename = typename,
        field_names = field_names)

    namespace = dict(__name__='struct_%s' % typename)
    exec(class_definition, namespace)
    result = namespace[typename]
    result._source = class_definition

    return result

Usage:

Person = struct('Person', ['firstname','lastname'])
generic = Person()
michael = Person('Michael')
jones = Person(lastname = 'Jones')


In [168]: michael.middlename = 'ben'
Traceback (most recent call last):

  File "<ipython-input-168-b31c393c0d67>", line 1, in <module>
michael.middlename = 'ben'

  File "<string>", line 19, in __setattr__

KeyError: 'invalid name: middlename'

Change the class from factor to numeric of many columns in a data frame

I know this question is long resolved, but I recently had a similar issue and think I've found a little more elegant and functional solution, although it requires the magrittr package.

library(magrittr)
cols = c(1, 3, 4, 5)
df[,cols] %<>% lapply(function(x) as.numeric(as.character(x)))

The %<>% operator pipes and reassigns, which is very useful for keeping data cleaning and transformation simple. Now the list apply function is much easier to read, by only specifying the function you wish to apply.

Access an arbitrary element in a dictionary in Python

Subclassing dict is one method, though not efficient. Here if you supply an integer it will return d[list(d)[n]], otherwise access the dictionary as expected:

class mydict(dict):
    def __getitem__(self, value):
        if isinstance(value, int):
            return self.get(list(self)[value])
        else:
            return self.get(value)

d = mydict({'a': 'hello', 'b': 'this', 'c': 'is', 'd': 'a',
            'e': 'test', 'f': 'dictionary', 'g': 'testing'})

d[0]    # 'hello'
d[1]    # 'this'
d['c']  # 'is'

Using find to locate files that match one of multiple patterns

This works on AIX korn shell.

find *.cbl *.dms -prune -type f -mtime -1

This is looking for *.cbl or *.dms which are 1 day old, in current directory only, skipping the sub-directories.

How to install JDK 11 under Ubuntu?

First check the default-jdk package, good chance it already provide you an OpenJDK >= 11.
ref: https://packages.ubuntu.com/search?keywords=default-jdk&searchon=names&suite=all&section=all

Ubuntu 18.04 LTS +

So starting from Ubuntu 18.04 LTS it should be ok.

sudo apt update -qq
sudo apt install -yq default-jdk

note: don't forget to set JAVA_HOME

export JAVA_HOME=/usr/lib/jvm/default-java
mvn -version

Ubuntu 16.04 LTS

For Ubuntu 16.04 LTS, only openjdk-8-jdk is provided in the official repos so you need to find it in a ppa:

sudo add-apt-repository -y ppa:openjdk-r/ppa
sudo apt update -qq
sudo apt install -yq openjdk-11-jdk

note: don't forget to set JAVA_HOME

export JAVA_HOME=/usr/lib/jvm/java-11-openjdk-amd64
mvn -version

How to enable Bootstrap tooltip on disabled button?

You can simply override Bootstrap's "pointer-events" style for disabled buttons via CSS e.g.

.btn[disabled] {
 pointer-events: all !important;
}

Better still be explicit and disable specific buttons e.g.

#buttonId[disabled] {
 pointer-events: all !important;
}

Set cURL to use local virtual hosts

EDIT: While this is currently accepted answer, readers might find this other answer by user John Hart more adapted to their needs. It uses an option which, according to user Ken, was introduced in version 7.21.3 (which was released in December 2010, i.e. after this initial answer).


In your edited question, you're using the URL as the host name, whereas it needs to be the host name only.

Try:

curl -H 'Host: project1.loc' http://127.0.0.1/something

where project1.loc is just the host name and 127.0.0.1 is the target IP address.

(If you're using curl from a library and not on the command line, make sure you don't put http:// in the Host header.)

How to call a php script/function on a html button click

You can also use

   $(document).ready(function() {

    //some even that will run ajax request - for example click on a button

    var uname = $('#username').val();
    $.ajax({
    type: 'POST',
    url: 'func.php', //this should be url to your PHP file
    dataType: 'html',
    data: {func: 'toptable', user_id: uname},
    beforeSend: function() {
        $('#right').html('checking');
    },
    complete: function() {},
    success: function(html) {
        $('#right').html(html);
    }
    });

    });
And your func.php:

  function toptable()
 {
  echo 'something happens in here';
 }

Hope it helps somebody

storing user input in array

You're not actually going out after the values. You would need to gather them like this:

var title   = document.getElementById("title").value;
var name    = document.getElementById("name").value;
var tickets = document.getElementById("tickets").value;

You could put all of these in one array:

var myArray = [ title, name, tickets ];

Or many arrays:

var titleArr   = [ title ];
var nameArr    = [ name ];
var ticketsArr = [ tickets ];

Or, if the arrays already exist, you can use their .push() method to push new values onto it:

var titleArr = [];

function addTitle ( title ) {
  titleArr.push( title );
  console.log( "Titles: " + titleArr.join(", ") );
}

Your save button doesn't work because you refer to this.form, however you don't have a form on the page. In order for this to work you would need to have <form> tags wrapping your fields:

I've made several corrections, and placed the changes on jsbin: http://jsbin.com/ufanep/2/edit

The new form follows:

<form>
  <h1>Please enter data</h1>
  <input id="title" type="text" />
  <input id="name" type="text" />
  <input id="tickets" type="text" />
  <input type="button" value="Save" onclick="insert()" />
  <input type="button" value="Show data" onclick="show()" />
</form>
<div id="display"></div>

There is still some room for improvement, such as removing the onclick attributes (those bindings should be done via JavaScript, but that's beyond the scope of this question).

I've also made some changes to your JavaScript. I start by creating three empty arrays:

var titles  = [];
var names   = [];
var tickets = [];

Now that we have these, we'll need references to our input fields.

var titleInput  = document.getElementById("title");
var nameInput   = document.getElementById("name");
var ticketInput = document.getElementById("tickets");

I'm also getting a reference to our message display box.

var messageBox  = document.getElementById("display");

The insert() function uses the references to each input field to get their value. It then uses the push() method on the respective arrays to put the current value into the array.

Once it's done, it cals the clearAndShow() function which is responsible for clearing these fields (making them ready for the next round of input), and showing the combined results of the three arrays.

function insert ( ) {
 titles.push( titleInput.value );
 names.push( nameInput.value );
 tickets.push( ticketInput.value );

 clearAndShow();
}

This function, as previously stated, starts by setting the .value property of each input to an empty string. It then clears out the .innerHTML of our message box. Lastly, it calls the join() method on all of our arrays to convert their values into a comma-separated list of values. This resulting string is then passed into the message box.

function clearAndShow () {
  titleInput.value = "";
  nameInput.value = "";
  ticketInput.value = "";

  messageBox.innerHTML = "";

  messageBox.innerHTML += "Titles: " + titles.join(", ") + "<br/>";
  messageBox.innerHTML += "Names: " + names.join(", ") + "<br/>";
  messageBox.innerHTML += "Tickets: " + tickets.join(", ");
}

The final result can be used online at http://jsbin.com/ufanep/2/edit

How to create a HTML Cancel button that redirects to a URL

Thats what i am using try it.

<a href="index.php"><button style ="position:absolute;top:450px;left:1100px;height:30px;width:200px;"> Cancel </button></a>

Concatenate text files with Windows command line, dropping leading lines

In powershell:

Get-Content file1.txt | Out-File out.txt
Get-Content file2.txt | Select-Object -Skip 1 | Out-File -Append out.txt

"use database_name" command in PostgreSQL

The basic problem while migrating from MySQL I faced was, I thought of the term database to be same in PostgreSQL also, but it is not. So if we are going to switch the database from our application or pgAdmin, the result would not be as expected. As in my case, we have separate schemas (Considering PostgreSQL terminology here.) for each customer and separate admin schema. So in application, I have to switch between schemas.

For this, we can use the SET search_path command. This does switch the current schema to the specified schema name for the current session.

example:

SET search_path = different_schema_name;

This changes the current_schema to the specified schema for the session. To change it permanently, we have to make changes in postgresql.conf file.