Programs & Examples On #Dynamic linking

Dynamic linking is a system which allows libraries to remain separate from programs until loaded, contrast static linking.

Static linking vs dynamic linking

Static linking is a process in compile time when a linked content is copied into the primary binary and becomes a single binary.

Cons:

  • compile time is longer
  • output binary is bigger

Dynamic linking is a process in runtime when a linked content is loaded. This technic allows to:

  • upgrade linked binary without recompiling a primary one that increase an ABI stability[About]
  • has a single shared copy

Cons:

  • start time is slower(linked content should be copied)
  • linker errors are thrown in runtime

[iOS Static vs Dynamic framework]

When to use dynamic vs. static libraries

C++ programs are built in two phases

  1. Compilation - produces object code (.obj)
  2. Linking - produces executable code (.exe or .dll)

Static library (.lib) is just a bundle of .obj files and therefore isn't a complete program. It hasn't undergone the second (linking) phase of building a program. Dlls, on the other hand, are like exe's and therefore are complete programs.

If you build a static library, it isn't linked yet and therefore consumers of your static library will have to use the same compiler that you used (if you used g++, they will have to use g++).

If instead you built a dll (and built it correctly), you have built a complete program that all consumers can use, no matter which compiler they are using. There are several restrictions though, on exporting from a dll, if cross compiler compatibility is desired.

Telling gcc directly to link a library statically

It is possible of course, use -l: instead of -l. For example -l:libXYZ.a to link with libXYZ.a. Notice the lib written out, as opposed to -lXYZ which would auto expand to libXYZ.

How to read a file in other directory in python

Looks like you are trying to open a directory for reading as if it's a regular file. Many OSs won't let you do that. You don't need to anyway, because what you want (judging from your description) is

x_file = open(os.path.join(direct, "5_1.txt"), "r")  

or simply

x_file = open(direct+"/5_1.txt", "r")

Running script upon login mac

tl;dr: use OSX's native process launcher and manager, launchd.

To do so, make a launchctl daemon. You'll have full control over all aspects of the script. You can run once or keep alive as a daemon. In most cases, this is the way to go.

  1. Create a .plist file according to the instructions in the Apple Dev docs here or more detail below.
  2. Place in ~/Library/LaunchAgents
  3. Log in (or run manually via launchctl load [filename.plist])

For more on launchd, the wikipedia article is quite good and describes the system and its advantages over other older systems.


Here's the specific plist file to run a script at login.

Updated 2017/09/25 for OSX El Capitan and newer (credit to José Messias Jr):

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple Computer//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
   <key>Label</key>
   <string>com.user.loginscript</string>
   <key>ProgramArguments</key>
   <array><string>/path/to/executable/script.sh</string></array>
   <key>RunAtLoad</key>
   <true/>
</dict>
</plist>

Replace the <string> after the Program key with your desired command (note that any script referenced by that command must be executable: chmod a+x /path/to/executable/script.sh to ensure it is for all users).

Save as ~/Library/LaunchAgents/com.user.loginscript.plist

Run launchctl load ~/Library/LaunchAgents/com.user.loginscript.plist and log out/in to test (or to test directly, run launchctl start com.user.loginscript)

Tail /var/log/system.log for error messages.

The key is that this is a User-specific launchd entry, so it will be run on login for the given user. System-specific launch daemons (placed in /Library/LaunchDaemons) are run on boot.

If you want a script to run on login for all users, I believe LoginHook is your only option, and that's probably the reason it exists.

How to write to an existing excel file without overwriting data (using pandas)?

Old question, but I am guessing some people still search for this - so...

I find this method nice because all worksheets are loaded into a dictionary of sheet name and dataframe pairs, created by pandas with the sheetname=None option. It is simple to add, delete or modify worksheets between reading the spreadsheet into the dict format and writing it back from the dict. For me the xlsxwriter works better than openpyxl for this particular task in terms of speed and format.

Note: future versions of pandas (0.21.0+) will change the "sheetname" parameter to "sheet_name".

# read a single or multi-sheet excel file
# (returns dict of sheetname(s), dataframe(s))
ws_dict = pd.read_excel(excel_file_path,
                        sheetname=None)

# all worksheets are accessible as dataframes.

# easy to change a worksheet as a dataframe:
mod_df = ws_dict['existing_worksheet']

# do work on mod_df...then reassign
ws_dict['existing_worksheet'] = mod_df

# add a dataframe to the workbook as a new worksheet with
# ws name, df as dict key, value:
ws_dict['new_worksheet'] = some_other_dataframe

# when done, write dictionary back to excel...
# xlsxwriter honors datetime and date formats
# (only included as example)...
with pd.ExcelWriter(excel_file_path,
                    engine='xlsxwriter',
                    datetime_format='yyyy-mm-dd',
                    date_format='yyyy-mm-dd') as writer:

    for ws_name, df_sheet in ws_dict.items():
        df_sheet.to_excel(writer, sheet_name=ws_name)

For the example in the 2013 question:

ws_dict = pd.read_excel('Masterfile.xlsx',
                        sheetname=None)

ws_dict['Main'] = data_filtered[['Diff1', 'Diff2']]

with pd.ExcelWriter('Masterfile.xlsx',
                    engine='xlsxwriter') as writer:

    for ws_name, df_sheet in ws_dict.items():
        df_sheet.to_excel(writer, sheet_name=ws_name)

How to change port number in vue-cli project

As the time of this answer's writing (May 5th 2018), vue-cli has its configuration hosted at <your_project_root>/vue.config.js. To change the port, see below:

// vue.config.js
module.exports = {
  // ...
  devServer: {
    open: process.platform === 'darwin',
    host: '0.0.0.0',
    port: 8080, // CHANGE YOUR PORT HERE!
    https: false,
    hotOnly: false,
  },
  // ...
}

Full vue.config.js reference can be found here: https://cli.vuejs.org/config/#global-cli-config

Note that as stated in the docs, “All options for webpack-dev-server” (https://webpack.js.org/configuration/dev-server/) is available within the devServer section.

Certificate is trusted by PC but not by Android

I've recently ren into this issue with Commodo cert I bought on ssls.com and I've had 3 files:

domain-name.ca-bundle domain-name.crt and domain-name.p7b

I've had to set it up on Nginx and this is the command I ran:

cat domain-name.ca-bundle domain-name.crt > commodo-ssl-bundle.crt

I then used commodo-ssl-bundle.crt inside the Nginx config file and works like a charm.

Reference jars inside a jar

Default implementations of the classloader cannot load from a jar-within-a-jar: in order to do so, the entire 'sub-jar' would have to be loaded into memory, which defeats the random-access benefits of the jar format (reference pending - I'll make an edit once I find the documentation supporting this).

I recommend using a program such as JarSplice to bundle everything for you into one clean executable jar.

Edit: Couldn't find the source reference, but here's an un-resolved RFE off the Sun website describing this exact 'problem': http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=4648386

Also, you could 'test' that your program works by placing the library jar files in a \lib sub-directory of your classes directory, then running from the command line. In other words, with the following directory structure:

classes/org/sai/com/DerbyDemo.class
classes/org/sai/com/OtherClassFiles.class
classes/lib/derby.jar
classes/lib/derbyclient.jar

From the command line, navigate to the above-mentioned 'classes' directory, and type:

java -cp .:lib/* org.sai.com.DerbyDemo

Windows task scheduler error 101 launch failure code 2147943785

The user that is configured to run this scheduled task must have "Log on as a batch job" rights on the computer that hosts the exe you are launching. This can be configured on the local security policy of the computer that hosts the exe. You can change the policy (on the server hosting the exe) under

Administrative Tools -> Local Security Policy -> Local Policies -> User Rights Assignment -> Log On As Batch Job

Add your user to this list (you could also make the user account a local admin on the machine hosting the exe).

Finally, you could also simply copy your exe from the network location to your local computer and run it from there instead.

Note also that a domain policy could be restricting "Log on as a batch job" rights at your organization.

How to create nonexistent subdirectories recursively using Bash?

$ mkdir -p "$BACKUP_DIR/$client/$year/$month/$day"

NUnit vs. MbUnit vs. MSTest vs. xUnit.net

I know this is an old thread, but I thought I'd post a vote for xUnit.NET. While most of the other testing frameworks mentioned are all pretty much the same, xUnit.NET has taken a pretty unique, modern, and flexible approach to unit testing. It changes terminology, so you no longer define TestFixtures and Tests...you specify Facts and Theories about your code, which integrates better with the concept of what a test is from a TDD/BDD perspective.

xUnit.NET is also EXTREMELY extensible. Its FactAttribute and TraitAttribute attribute classes are not sealed, and provide overridable base methods that give you a lot of control over how the methods those attributes decorate should be executed. While xUnit.NET in its default form allows you to write test classes that are similar to NUnit test fixtures with their test methods, you are not confined to this form of unit testing at all. You are free to extend the framework to support BDD-style Concern/Context/Observation specifications, as depicted here.

xUnit.NET also supports fit-style testing directly out of the box with its Theory attribute and corresponding data attributes. Fit input data may be loaded from excel, database, or even a custom data source such as a Word document (by extending the base data attribute.) This allows you to capitalize on a single testing platform for both unit tests and integration tests, which can be huge in reducing product dependencies and required training.

Other approaches to testing may also be implemented with xUnit.NET...the possibilities are pretty limitless. Combined with another very forward looking mocking framework, Moq, the two create a very flexible, extensible, and powerful platform for implementing automated testing.

How to use workbook.saveas with automatic Overwrite

I recommend that before executing SaveAs, delete the file it exists.

If Dir("f:ull\path\with\filename.xls") <> "" Then
    Kill "f:ull\path\with\filename.xls"
End If

It's easier than setting DisplayAlerts off and on, plus if DisplayAlerts remains off due to code crash, it can cause problems if you work with Excel in the same session.

How to split a string of space separated numbers into integers?

text = "42 0"
nums = [int(n) for n in text.split()]

How can I create 2 separate log files with one log4j config file?

Modify your log4j.properties file accordingly:

log4j.rootLogger=TRACE,stdout
...
log4j.logger.debugLog=TRACE,debugLog
log4j.logger.reportsLog=DEBUG,reportsLog

Change the log levels for each logger depending to your needs.

Can an Android App connect directly to an online mysql database

You can use PHP, JSP, ASP or any other server side script to connect with mysql database and and return JSON data that you can parse it to in your android app this link how to do it

PDF Blob - Pop up window not showing content

You need to set the responseType to arraybuffer if you would like to create a blob from your response data:

$http.post('/fetchBlobURL',{myParams}, {responseType: 'arraybuffer'})
   .success(function (data) {
       var file = new Blob([data], {type: 'application/pdf'});
       var fileURL = URL.createObjectURL(file);
       window.open(fileURL);
});

more information: Sending_and_Receiving_Binary_Data

How to get the size of a range in Excel

The overall dimensions of a range are in its Width and Height properties.

Dim r As Range
Set r = ActiveSheet.Range("A4:H12")

Debug.Print r.Width
Debug.Print r.Height

Change all files and folders permissions of a directory to 644/755

Easiest for me to remember is two operations:

chmod -R 644 dirName
chmod -R +X dirName

The +X only affects directories.

What causes the error "undefined reference to (some function)"?

It's a linker error. ld is the linker, so if you get an error message ending with "ld returned 1 exit status", that tells you that it's a linker error.

The error message tells you that none of the object files you're linking against contains a definition for avergecolumns. The reason for that is that the function you've defined is called averagecolumns (in other words: you misspelled the function name when calling the function (and presumably in the header file as well - otherwise you'd have gotten a different error at compile time)).

Why does viewWillAppear not get called when an app comes back from the background?

Swift

Short answer

Use a NotificationCenter observer rather than viewWillAppear.

override func viewDidLoad() {
    super.viewDidLoad()

    // set observer for UIApplication.willEnterForegroundNotification
    NotificationCenter.default.addObserver(self, selector: #selector(willEnterForeground), name: UIApplication.willEnterForegroundNotification, object: nil)

}

// my selector that was defined above
@objc func willEnterForeground() {
    // do stuff
}

Long answer

To find out when an app comes back from the background, use a NotificationCenter observer rather than viewWillAppear. Here is a sample project that shows which events happen when. (This is an adaptation of this Objective-C answer.)

import UIKit
class ViewController: UIViewController {

    // MARK: - Overrides

    override func viewDidLoad() {
        super.viewDidLoad()
        print("view did load")

        // add notification observers
        NotificationCenter.default.addObserver(self, selector: #selector(didBecomeActive), name: UIApplication.didBecomeActiveNotification, object: nil)
        NotificationCenter.default.addObserver(self, selector: #selector(willEnterForeground), name: UIApplication.willEnterForegroundNotification, object: nil)

    }

    override func viewWillAppear(_ animated: Bool) {
        print("view will appear")
    }

    override func viewDidAppear(_ animated: Bool) {
        print("view did appear")
    }

    // MARK: - Notification oberserver methods

    @objc func didBecomeActive() {
        print("did become active")
    }

    @objc func willEnterForeground() {
        print("will enter foreground")
    }

}

On first starting the app, the output order is:

view did load
view will appear
did become active
view did appear

After pushing the home button and then bringing the app back to the foreground, the output order is:

will enter foreground
did become active 

So if you were originally trying to use viewWillAppear then UIApplication.willEnterForegroundNotification is probably what you want.

Note

As of iOS 9 and later, you don't need to remove the observer. The documentation states:

If your app targets iOS 9.0 and later or macOS 10.11 and later, you don't need to unregister an observer in its dealloc method.

How to grep (search) committed code in the Git history

I took Jeet's answer and adapted it to Windows (thanks to this answer):

FOR /F %x IN ('"git rev-list --all"') DO @git grep <regex> %x > out.txt

Note that for me, for some reason, the actual commit that deleted this regex did not appear in the output of the command, but rather one commit prior to it.

Open fancybox from function

You don't have to add you own click event handler at all. Just initialize the element with fancybox:

$(function() {
    $('a[href="#modalMine"]').fancybox({
        'autoScale': true,
        'transitionIn': 'elastic',
        'transitionOut': 'elastic',
        'speedIn': 500,
        'speedOut': 300,
        'autoDimensions': true,
        'centerOnScroll': true  // as MattBall already said, remove the comma
    });
});

Done. Fancybox already binds a click handler that opens the box. Have a look at the HowTo section.


Later if you want to open the box programmatically, raise the click event on that element:

$('a[href="#modalMine"]').click();

How to read a text file directly from Internet using Java?

What really worked to me: (source: oracle documentation "reading url")

 import java.net.*;
 import java.io.*;

 public class UrlTextfile {
public static void main(String[] args) throws Exception {

    URL oracle = new URL("http://yoursite.com/yourfile.txt");
    BufferedReader in = new BufferedReader(
    new InputStreamReader(oracle.openStream()));

    String inputLine;
    while ((inputLine = in.readLine()) != null)
        System.out.println(inputLine);
    in.close();
}
 }

Relative path to absolute path in C#?

This worked for me.

//used in an ASP.NET MVC app
private const string BatchFilePath = "/MyBatchFileDirectory/Mybatchfiles.bat"; 
var batchFile = HttpContext.Current.Server.MapPath(BatchFilePath);

Find records from one table which don't exist in another

SELECT t1.ColumnID,
CASE 
    WHEN NOT EXISTS( SELECT t2.FieldText  
                     FROM Table t2 
                     WHERE t2.ColumnID = t1.ColumnID) 
    THEN t1.FieldText
    ELSE t2.FieldText
END FieldText       
FROM Table1 t1, Table2 t2

Multiple Image Upload PHP form with one input

$total = count($_FILES['txt_gallery']['name']);
            $filename_arr = [];
            $filename_arr1 = [];
            for( $i=0 ; $i < $total ; $i++ ) {
              $tmpFilePath = $_FILES['txt_gallery']['tmp_name'][$i];
              if ($tmpFilePath != ""){
                $newFilePath = "../uploaded/" .date('Ymdhis').$i.$_FILES['txt_gallery']['name'][$i];
                $newFilePath1 = date('Ymdhis').$i.$_FILES['txt_gallery']['name'][$i];
                if(move_uploaded_file($tmpFilePath, $newFilePath)) {
                  $filename_arr[] = $newFilePath;
                  $filename_arr1[] = $newFilePath1;

                }
              }
            }
            $file_names = implode(',', $filename_arr1);
            var_dump($file_names); exit;

Safe Area of Xcode 9

Apple introduced the topLayoutGuide and bottomLayoutGuide as properties of UIViewController way back in iOS 7. They allowed you to create constraints to keep your content from being hidden by UIKit bars like the status, navigation or tab bar. These layout guides are deprecated in iOS 11 and replaced by a single safe area layout guide.

Refer link for more information.

Find location of a removable SD card

The only working solution I found was this one that uses reflection

 /**
 * Get external sd card path using reflection
 * @param mContext
 * @param is_removable is external storage removable
 * @return
 */
private static String getExternalStoragePath(Context mContext, boolean is_removable) {

    StorageManager mStorageManager = (StorageManager) mContext.getSystemService(Context.STORAGE_SERVICE);
    Class<?> storageVolumeClazz = null;
    try {
        storageVolumeClazz = Class.forName("android.os.storage.StorageVolume");
        Method getVolumeList = mStorageManager.getClass().getMethod("getVolumeList");
        Method getPath = storageVolumeClazz.getMethod("getPath");
        Method isRemovable = storageVolumeClazz.getMethod("isRemovable");
        Object result = getVolumeList.invoke(mStorageManager);
        final int length = Array.getLength(result);
        for (int i = 0; i < length; i++) {
            Object storageVolumeElement = Array.get(result, i);
            String path = (String) getPath.invoke(storageVolumeElement);
            boolean removable = (Boolean) isRemovable.invoke(storageVolumeElement);
            if (is_removable == removable) {
                return path;
            }
        }
    } catch (ClassNotFoundException e) {
        e.printStackTrace();
    } catch (InvocationTargetException e) {
        e.printStackTrace();
    } catch (NoSuchMethodException e) {
        e.printStackTrace();
    } catch (IllegalAccessException e) {
        e.printStackTrace();
    }
    return null;
}

How to add/update an attribute to an HTML element using JavaScript?

What seems easy is actually tricky if you want to be completely compatible.

var e = document.createElement('div');

Let's say you have an id of 'div1' to add.

e['id'] = 'div1';
e.id = 'div1';
e.attributes['id'] = 'div1';
e.createAttribute('id','div1')
These will all work except the last in IE 5.5 (which is ancient history at this point but still is XP's default with no updates).

But there are contingencies, of course. Will not work in IE prior to 8:e.attributes['style'] Will not error but won't actually set the class, it must be className:e['class'] .
However, if you're using attributes then this WILL work:e.attributes['class']

In summary, think of attributes as literal and object-oriented.

In literal, you just want it to spit out x='y' and not think about it. This is what attributes, setAttribute, createAttribute is for (except for IE's style exception). But because these are really objects things can get confused.

Since you are going to the trouble of properly creating a DOM element instead of jQuery innerHTML slop, I would treat it like one and stick with the e.className = 'fooClass' and e.id = 'fooID'. This is a design preference, but in this instance trying to treat is as anything other than an object works against you.

It will never backfire on you like the other methods might, just be aware of class being className and style being an object so it's style.width not style="width:50px". Also remember tagName but this is already set by createElement so you shouldn't need to worry about it.

This was longer than I wanted, but CSS manipulation in JS is tricky business.

How to use JQuery with ReactJS

Yes, we can use jQuery in ReactJs. Here I will tell how we can use it using npm.

step 1: Go to your project folder where the package.json file is present via using terminal using cd command.

step 2: Write the following command to install jquery using npm : npm install jquery --save

step 3: Now, import $ from jquery into your jsx file where you need to use.

Example:

write the below in index.jsx

import React from 'react';
import ReactDOM from 'react-dom';
import $ from 'jquery';


//   react code here


$("button").click(function(){
    $.get("demo_test.asp", function(data, status){
        alert("Data: " + data + "\nStatus: " + status);
    });
});

// react code here

write the below in index.html

<!DOCTYPE html>
<html>
<head>
    <script src="index.jsx"></script>
    <!-- other scripting files -->
</head>
<body>
    <!-- other useful tags -->
    <div id="div1">
        <h2>Let jQuery AJAX Change This Text</h2>
    </div>
    <button>Get External Content</button>
</body>
</html>

How to validate email id in angularJs using ng-pattern

I have tried wit the below regex it is working fine.

Email validation : \w+([-+.']\w+)@\w+([-.]\w+).\w+([-.]\w+)*

How do I install Maven with Yum?

yum install -y yum-utils

yum-config-manager --add-repo http://repos.fedorapeople.org/repos/dchen/apache-maven/epel-apache-maven.repo

yum-config-manager --enable epel-apache-maven

yum install -y apache-maven

for JVM developer, this is a SDK manager for all the tool you need.

https://sdkman.io/

Install sdkman:

yum install -y zip unzip

curl -s "https://get.sdkman.io" | bash

source "$HOME/.sdkman/bin/sdkman-init.sh"

Install Maven:

sdk install maven

How do I install the yaml package for Python?

Type in pip3 install yaml or like Connor pip3 install strictyaml

Can not deserialize instance of java.lang.String out of START_OBJECT token

If you do not want to define a separate class for nested json , Defining nested json object as JsonNode should work ,for example :

{"id":2,"socket":"0c317829-69bf-43d6-b598-7c0c550635bb","type":"getDashboard","data":{"workstationUuid":"ddec1caa-a97f-4922-833f-632da07ffc11"},"reply":true}

@JsonProperty("data")
    private JsonNode data;

Build project into a JAR automatically in Eclipse

Creating a builder launcher is an issue since 2 projects cannot have the same external tool build name. Each name has to be unique. I am currently facing this issue to automate my build and copy the JAR to an external location.

I am using IBM's Zip Builder, but that is just a help but not doing the real.

People can try using IBM ZIP Creation plugin. http://www.ibm.com/developerworks/websphere/library/techarticles/0112_deboer/deboer2.html#download

Copy all values from fields in one class to another through reflection

Orika's is simple faster bean mapping framework because it does through byte code generation. It does nested mappings and mappings with different names. For more details, please check here Sample mapping may look complex, but for complex scenarios it would be simple.

MapperFactory factory = new DefaultMapperFactory.Builder().build();
mapperFactory.registerClassMap(mapperFactory.classMap(Book.class,BookDto.class).byDefault().toClassMap());
MapperFacade mapper = factory.getMapperFacade();
BookDto bookDto = mapperFacade.map(book, BookDto.class);

Creating a JSON dynamically with each input value using jquery

same from above example - if you are just looking for json (not an array of object) just use

function getJsonDetails() {
      item = {}
      item ["token1"] = token1val;
      item ["token2"] = token1val;
      return item;
}
console.log(JSON.stringify(getJsonDetails()))

this output ll print as (a valid json)

{ 
   "token1":"samplevalue1",
   "token2":"samplevalue2"
}

PHP/MySQL: How to create a comment section in your website

You can create a 'comment' table, with an id as primary key, then you add a text field to capture the text inserted by the user and you need another field to link the comment table to the article table (foreign key). Plus you need a field to store the user that has entered a comment, this field can be the user's email. Then you capture via GET or POST the user's email and comment and you insert everything in the DB:

"INSERT INTO comment (comment, email, approved) VALUES ('$comment', '$email', '$approved')"

This is a first hint. Of course adding a comment feature it takes a little bit. Then you should think about a form to let the admin to approve the comments and how to publish the comments in the end of articles.

Is it possible to append Series to rows of DataFrame without making a list first?

Maybe an easier way would be to add the pandas.Series into the pandas.DataFrame with ignore_index=True argument to DataFrame.append(). Example -

DF = DataFrame()
for sample,data in D_sample_data.items():
    SR_row = pd.Series(data.D_key_value)
    DF = DF.append(SR_row,ignore_index=True)

Demo -

In [1]: import pandas as pd

In [2]: df = pd.DataFrame([[1,2],[3,4]],columns=['A','B'])

In [3]: df
Out[3]:
   A  B
0  1  2
1  3  4

In [5]: s = pd.Series([5,6],index=['A','B'])

In [6]: s
Out[6]:
A    5
B    6
dtype: int64

In [36]: df.append(s,ignore_index=True)
Out[36]:
   A  B
0  1  2
1  3  4
2  5  6

Another issue in your code is that DataFrame.append() is not in-place, it returns the appended dataframe, you would need to assign it back to your original dataframe for it to work. Example -

DF = DF.append(SR_row,ignore_index=True)

To preserve the labels, you can use your solution to include name for the series along with assigning the appended DataFrame back to DF. Example -

DF = DataFrame()
for sample,data in D_sample_data.items():
    SR_row = pd.Series(data.D_key_value,name=sample)
    DF = DF.append(SR_row)
DF.head()

Could not load dynamic library 'cudart64_101.dll' on tensorflow CPU-only installation

Tensorflow gpu 2.2 and 2.3 nightly

(along CUDA Toolkit 11.0 RC)

To solve the same issue as OP, I just had to find cudart64_101.dll on my disk (in my case C:\Program Files\NVIDIA Corporation\NvStreamSrv) and add it as variable environment (that is add value C:\Program Files\NVIDIA\Corporation\NvStreamSrv)cudart64_101.dll to user's environment variable Path).

SSRS custom number format

You can use

 =Format(Fields!myField.Value,"F2") 

Hibernate show real SQL

select this_.code from true.employee this_ where this_.code=? is what will be sent to your database.

this_ is an alias for that instance of the employee table.

utf-8 special characters not displaying

set meta tag in head as

 <meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1" /> 

use the link http://www.i18nqa.com/debug/utf8-debug.html to replace the symbols character you want.

then use str_replace like

    $find = array('“', '’', '…', '—', '–', '‘', 'é', 'Â', '•', 'Ëœ', 'â€'); // en dash
                        $replace = array('“', '’', '…', '—', '–', '‘', 'é', '', '•', '˜', '”');
$content = str_replace($find, $replace, $content);

Its the method i use and help alot. Thanks!

How to load image files with webpack file-loader

Alternatively you can write the same like

{
    test: /\.(svg|png|jpg|jpeg|gif)$/,
    include: 'path of input image directory',
    use: {
        loader: 'file-loader',
        options: {
            name: '[path][name].[ext]',
            outputPath: 'path of output image directory'
        }
    }
}

and then use simple import

import varName from 'relative path';

and in jsx write like <img src={varName} ..../>

.... are for other image attributes

How to calculate the intersection of two sets?

Use the retainAll() method of Set:

Set<String> s1;
Set<String> s2;
s1.retainAll(s2); // s1 now contains only elements in both sets

If you want to preserve the sets, create a new set to hold the intersection:

Set<String> intersection = new HashSet<String>(s1); // use the copy constructor
intersection.retainAll(s2);

The javadoc of retainAll() says it's exactly what you want:

Retains only the elements in this set that are contained in the specified collection (optional operation). In other words, removes from this set all of its elements that are not contained in the specified collection. If the specified collection is also a set, this operation effectively modifies this set so that its value is the intersection of the two sets.

Set mouse focus and move cursor to end of input using jQuery

Here is another one, a one liner which does not reassign the value:

$("#inp").focus()[0].setSelectionRange(99999, 99999);

How to choose an AWS profile when using boto3 to connect to CloudFront

Do this to use a profile with name 'dev':

session = boto3.session.Session(profile_name='dev')
s3 = session.resource('s3')
for bucket in s3.buckets.all():
    print(bucket.name)

Check if a specific tab page is selected (active)

Assuming you are looking out in Winform, there is a SelectedIndexChanged event for the tab

Now in it you could check for your specific tab and proceed with the logic

private void tab1_SelectedIndexChanged(object sender, EventArgs e)
{
     if (tab1.SelectedTab == tab1.TabPages["tabname"])//your specific tabname
     {
         // your stuff
     }
}

Difference between uint32 and uint32_t

uint32_t is standard, uint32 is not. That is, if you include <inttypes.h> or <stdint.h>, you will get a definition of uint32_t. uint32 is a typedef in some local code base, but you should not expect it to exist unless you define it yourself. And defining it yourself is a bad idea.

Setting POST variable without using form

If you want to set $_POST['text'] to another value, why not use:

$_POST['text'] = $var;

on next.php?

'Invalid update: invalid number of rows in section 0

In my case issue was that numberOfRowsInSection was returning similar number of rows after calling tableView.deleteRows(...).

Since this was the required behaviour in my case, I ended up calling tableView.reloadData() instead of tableView.deleteRows(...) in cases where numberOfRowsInSection will remain same after deleting a row.

Converting PKCS#12 certificate into PEM using OpenSSL

If you can use Python, it is even easier if you have the pyopenssl module. Here it is:

from OpenSSL import crypto

# May require "" for empty password depending on version

with open("push.p12", "rb") as file:
    p12 = crypto.load_pkcs12(file.read(), "my_passphrase")

# PEM formatted private key
print crypto.dump_privatekey(crypto.FILETYPE_PEM, p12.get_privatekey())

# PEM formatted certificate
print crypto.dump_certificate(crypto.FILETYPE_PEM, p12.get_certificate())

How to get last inserted row ID from WordPress database?

I needed to get the last id way after inserting it, so

$lastid = $wpdb->insert_id;

Was not an option.

Did the follow:

global $wpdb;
$id = $wpdb->get_var( 'SELECT id FROM ' . $wpdb->prefix . 'table' . ' ORDER BY id DESC LIMIT 1');

How to copy multiple files in one layer using a Dockerfile?

simple

COPY README.md  package.json gulpfile.js __BUILD_NUMBER ./

from the doc

If multiple resources are specified, either directly or due to the use of a wildcard, then must be a directory, and it must end with a slash /.

How to use LINQ Distinct() with multiple fields

Answering the headline of the question (what attracted people here) and ignoring that the example used anonymous types....

This solution will also work for non-anonymous types. It should not be needed for anonymous types.

Helper class:

/// <summary>
/// Allow IEqualityComparer to be configured within a lambda expression.
/// From https://stackoverflow.com/questions/98033/wrap-a-delegate-in-an-iequalitycomparer
/// </summary>
/// <typeparam name="T"></typeparam>
public class LambdaEqualityComparer<T> : IEqualityComparer<T>
{
    readonly Func<T, T, bool> _comparer;
    readonly Func<T, int> _hash;

    /// <summary>
    /// Simplest constructor, provide a conversion to string for type T to use as a comparison key (GetHashCode() and Equals().
    /// https://stackoverflow.com/questions/98033/wrap-a-delegate-in-an-iequalitycomparer, user "orip"
    /// </summary>
    /// <param name="toString"></param>
    public LambdaEqualityComparer(Func<T, string> toString)
        : this((t1, t2) => toString(t1) == toString(t2), t => toString(t).GetHashCode())
    {
    }

    /// <summary>
    /// Constructor.  Assumes T.GetHashCode() is accurate.
    /// </summary>
    /// <param name="comparer"></param>
    public LambdaEqualityComparer(Func<T, T, bool> comparer)
        : this(comparer, t => t.GetHashCode())
    {
    }

    /// <summary>
    /// Constructor, provide a equality comparer and a hash.
    /// </summary>
    /// <param name="comparer"></param>
    /// <param name="hash"></param>
    public LambdaEqualityComparer(Func<T, T, bool> comparer, Func<T, int> hash)
    {
        _comparer = comparer;
        _hash = hash;
    }

    public bool Equals(T x, T y)
    {
        return _comparer(x, y);
    }

    public int GetHashCode(T obj)
    {
        return _hash(obj);
    }    
}

Simplest usage:

List<Product> products = duplicatedProducts.Distinct(
    new LambdaEqualityComparer<Product>(p =>
        String.Format("{0}{1}{2}{3}",
            p.ProductId,
            p.ProductName,
            p.CategoryId,
            p.CategoryName))
        ).ToList();

The simplest (but not that efficient) usage is to map to a string representation so that custom hashing is avoided. Equal strings already have equal hash codes.

Reference:
Wrap a delegate in an IEqualityComparer

Ajax call Into MVC Controller- Url Issue

starting from mihai-labo's answer, why not skip declaring the requrl variable altogether and put the url generating code directly in front of "url:", like:

 $.ajax({
    type: "POST",
    url: '@Url.Action("Action", "Controller", null, Request.Url.Scheme, null)',
    data: "{queryString:'" + searchVal + "'}",
    contentType: "application/json; charset=utf-8",
    dataType: "html",
    success: function (data) {
        alert("here" + data.d.toString());
    }
});

How to set a Javascript object values dynamically?

myObj.name=value

or

myObj['name']=value     (Quotes are required)

Both of these are interchangeable.

Edit: I'm guessing you meant myObj[prop] = value, instead of myObj[name] = value. Second syntax works fine: http://jsfiddle.net/waitinforatrain/dNjvb/1/

How do I type a TAB character in PowerShell?

TAB has a specific meaning in PowerShell. It's for command completion. So if you enter "getch" and then type a TAB. It changes what you typed into "GetChildItem" (it corrects the case, even though that's unnecessary).

From your question, it looks like TAB completion and command completion would overload the TAB key. I'm pretty sure the PowerShell designers didn't want that.

Android studio takes too much memory

In my case, there were two main sources of memory hogging: the IDE and Gradle:

Android Studio (up to 1.5GB)

The IDE's JVM is configured to have a max heap size. You can see this in the lower-right corner of the main interface:

Android Studio showing 725M max heap size

You can reduce this by editing the memory-related settings in the .vmoptions file. For example, I changed my max heap size to 512MB:

-Xmx512m

Unfortunately, I found that lowering this value increases the frequency of Android Studio temporarily freezing, perhaps to do its garbage collection.

Gradle (up to 1.5GB)

Gradle can also use a lot of RAM after developing for a while. Windows just shows it as Java(TM) Platform SE Binary:

Windows 8.1 Task Manager showing "Java(TM Platform SE binary" using 1,460.5 MB of memory

You can fix this by changing the Gradle JVM options. You can do this on a per-user basis by editing gradle.properties:

  1. Open the gradle.properties file, creating it if it doesn't exist:
    • Windows: %USERPROFILE%\.gradle\gradle.properties
    • Linux/Mac: ~/.gradle/gradle.properties
  2. Update the org.gradle.jvmargs property, creating it if necessary. I set mine to this:

    org.gradle.jvmargs=-Xmx256m -XX:MaxPermSize=256m -XX:+HeapDumpOnOutOfMemoryError -Dfile.encoding=UTF-8
    

I haven't noticed any difference in build performance for my small project with the max heap size set to 256MB (-Xmx256m).

Note that you might need to restart Android Studio so the old Gradle process is killed; otherwise you might end up with both running at the same time.

Emulator

Regarding the emulator taking up a lot of your RAM, your screenshot shows it taking about 800MB. You can choose how much RAM to allocate to the emulator:

  1. Edit the AVD
  2. Press Show Advanced Settings
  3. Reduce the value of RAM

Android Virtual Device RAM configuration

how to increase MaxReceivedMessageSize when calling a WCF from C#

Change the customBinding in the web.config to use larger defaults. I picked 2MB as it is a reasonable size. Of course setting it to 2GB (as your code suggests) will work but it does leave you more vulnerable to attacks. Pick a size that is larger than your largest request but isn't overly large.

Check this : Using Large Message Requests in Silverlight with WCF

<system.serviceModel>
   <behaviors>
     <serviceBehaviors>
       <behavior name="TestLargeWCF.Web.MyServiceBehavior">
         <serviceMetadata httpGetEnabled="true"/>
         <serviceDebug includeExceptionDetailInFaults="false"/>
       </behavior>
     </serviceBehaviors>
   </behaviors>
   <bindings>
     <customBinding>
       <binding name="customBinding0">
         <binaryMessageEncoding />
         <!-- Start change -->
         <httpTransport maxReceivedMessageSize="2097152"
                        maxBufferSize="2097152"
                        maxBufferPoolSize="2097152"/>
         <!-- Stop change -->
       </binding>
     </customBinding>
   </bindings>
   <serviceHostingEnvironment aspNetCompatibilityEnabled="true"/>
   <services>
     <service behaviorConfiguration="Web.MyServiceBehavior" name="TestLargeWCF.Web.MyService">
       <endpoint address=""
                binding="customBinding"
                bindingConfiguration="customBinding0"
                contract="TestLargeWCF.Web.MyService"/>
       <endpoint address="mex"
                binding="mexHttpBinding"
                contract="IMetadataExchange"/>
     </service>
   </services>
 </system.serviceModel> 

How to install python modules without root access?

You can run easy_install to install python packages in your home directory even without root access. There's a standard way to do this using site.USER_BASE which defaults to something like $HOME/.local or $HOME/Library/Python/2.7/bin and is included by default on the PYTHONPATH

To do this, create a .pydistutils.cfg in your home directory:

cat > $HOME/.pydistutils.cfg <<EOF
[install]
user=1
EOF

Now you can run easy_install without root privileges:

easy_install boto

Alternatively, this also lets you run pip without root access:

pip install boto

This works for me.

Source from Wesley Tanaka's blog : http://wtanaka.com/node/8095

difference between new String[]{} and new String[] in java

TL;DR

  • An array variable has to be typed T[]
    (note that T can be an arry type itself -> multidimensional arrays)
  • The length of the array must be determined either by:
    • giving it an explicit size
      (can be int constant or int expression, see n below)
    • initializing all the values inside the array
      (length is implicitly calculated from given elements)
  • Any variable that is typed T[] has one read-only field: length and an index operator [int] for reading/writing data at certain indices.

Replies

1. String[] array= new String[]{}; what is the use of { } here ?

It initializes the array with the values between { }. In this case 0 elements, so array.length == 0 and array[0] throws IndexOutOfBoundsException: 0.

2. what is the diff between String array=new String[]; and String array=new String[]{};

The first won't compile for two reasons while the second won't compile for one reason. The common reason is that the type of the variable array has to be an array type: String[] not just String. Ignoring that (probably just a typo) the difference is:

new String[]   // size not known, compile error
new String[]{} // size is known, it has 0 elements, listed inside {}
new String[0]  // size is known, it has 0 elements, explicitly sized

3. when am writing String array=new String[10]{}; got error why ?

(Again, ignoring the missing [] before array) In this case you're over-eager to tell Java what to do and you're giving conflicting data. First you tell Java that you want 10 elements for the array to hold and then you're saying you want the array to be empty via {}. Just make up your mind and use one of those - Java thinks.

help me i am confused

Examples

String[] noStrings = new String[0];
String[] noStrings = new String[] { };
String[] oneString = new String[] { "atIndex0" };
String[] oneString = new String[1];
String[] oneString = new String[] { null }; // same as previous
String[] threeStrings = new String[] { "atIndex0", "atIndex1", "atIndex2" };
String[] threeStrings = new String[] { "atIndex0", null, "atIndex2" }; // you can skip an index
String[] threeStrings = new String[3];
String[] threeStrings = new String[] { null, null, null }; // same as previous
int[] twoNumbers = new int[2];
int[] twoNumbers = new int[] { 0, 0 }; // same as above
int[] twoNumbers = new int[] { 1, 2 }; // twoNumbers.length == 2 && twoNumbers[0] == 1 && twoNumbers[1] == 2
int n = 2;
int[] nNumbers = new int[n]; // same as [2] and { 0, 0 }
int[] nNumbers = new int[2*n]; // same as new int[4] if n == 2

(Here, "same as" means it will construct the same array.)

How to Get the Current URL Inside @if Statement (Blade) in Laravel 4?

For named routes, I use:

@if(url()->current() == route('routeName')) class="current" @endif

Make Axios send cookies in its requests automatically

What worked for me:

Client Side:

import axios from 'axios';

const url = 'http://127.0.0.1:5000/api/v1';

export default {
  login(credentials) {
    return axios
      .post(`${url}/users/login/`, credentials, {
        withCredentials: true,
        credentials: 'include',
      })
      .then((response) => response.data);
  },
};

Server Side:

const express = require('express');
const cors = require('cors');

const app = express();
const port = process.env.PORT || 5000;

app.use(
  cors({
    origin: [`http://localhost:${port}`, `https://localhost:${port}`],
    credentials: 'true',
  })
);

Failed to load resource 404 (Not Found) - file location error?

Looks like the path you gave doesn't have any bootstrap files in them.

href="~/lib/bootstrap/dist/css/bootstrap.min.css"

Make sure the files exist over there , else point the files to the correct path, which should be in your case

href="~/node_modules/bootstrap/dist/css/bootstrap.min.css"

How to get just the date part of getdate()?

Try this:

SELECT CONVERT(date, GETDATE())

Passing command line arguments to R CMD BATCH

You need to put arguments before my_script.R and use - on the arguments, e.g.

R CMD BATCH -blabla my_script.R

commandArgs() will receive -blabla as a character string in this case. See the help for details:

$ R CMD BATCH --help
Usage: R CMD BATCH [options] infile [outfile]

Run R non-interactively with input from infile and place output (stdout
and stderr) to another file.  If not given, the name of the output file
is the one of the input file, with a possible '.R' extension stripped,
and '.Rout' appended.

Options:
  -h, --help        print short help message and exit
  -v, --version     print version info and exit
  --no-timing           do not report the timings
  --            end processing of options

Further arguments starting with a '-' are considered as options as long
as '--' was not encountered, and are passed on to the R process, which
by default is started with '--restore --save --no-readline'.
See also help('BATCH') inside R.

Setting the height of a DIV dynamically

inspired by @jason-bunting, same thing for either height or width:

function resizeElementDimension(element, doHeight) {
  dim = (doHeight ? 'Height' : 'Width')
  ref = (doHeight ? 'Top' : 'Left')

  var x = 0;
  var body = window.document.body;
  if(window['inner' + dim])
    x = window['inner' + dim]
  else if (body.parentElement['client' + dim])
    x = body.parentElement['client' + dim]
  else if (body && body['client' + dim])
    x = body['client' + dim]

  element.style[dim.toLowerCase()] = ((x - element['offset' + ref]) + "px");
}

How to detect a mobile device with JavaScript?

Similar to several of the answers above. This simple function, works very well for me. It is current as of 2019

function IsMobileCard()
{
var check =  false;

(function(a){if(/(android|bb\d+|meego).+mobile|avantgo|bada\/|blackberry|blazer|compal|elaine|fennec|hiptop|iemobile|ip(hone|od)|iris|kindle|lge |maemo|midp|mmp|mobile.+firefox|netfront|opera m(ob|in)i|palm( os)?|phone|p(ixi|re)\/|plucker|pocket|psp|series(4|6)0|symbian|treo|up\.(browser|link)|vodafone|wap|windows ce|xda|xiino/i.test(a)||/1207|6310|6590|3gso|4thp|50[1-6]i|770s|802s|a wa|abac|ac(er|oo|s\-)|ai(ko|rn)|al(av|ca|co)|amoi|an(ex|ny|yw)|aptu|ar(ch|go)|as(te|us)|attw|au(di|\-m|r |s )|avan|be(ck|ll|nq)|bi(lb|rd)|bl(ac|az)|br(e|v)w|bumb|bw\-(n|u)|c55\/|capi|ccwa|cdm\-|cell|chtm|cldc|cmd\-|co(mp|nd)|craw|da(it|ll|ng)|dbte|dc\-s|devi|dica|dmob|do(c|p)o|ds(12|\-d)|el(49|ai)|em(l2|ul)|er(ic|k0)|esl8|ez([4-7]0|os|wa|ze)|fetc|fly(\-|_)|g1 u|g560|gene|gf\-5|g\-mo|go(\.w|od)|gr(ad|un)|haie|hcit|hd\-(m|p|t)|hei\-|hi(pt|ta)|hp( i|ip)|hs\-c|ht(c(\-| |_|a|g|p|s|t)|tp)|hu(aw|tc)|i\-(20|go|ma)|i230|iac( |\-|\/)|ibro|idea|ig01|ikom|im1k|inno|ipaq|iris|ja(t|v)a|jbro|jemu|jigs|kddi|keji|kgt( |\/)|klon|kpt |kwc\-|kyo(c|k)|le(no|xi)|lg( g|\/(k|l|u)|50|54|\-[a-w])|libw|lynx|m1\-w|m3ga|m50\/|ma(te|ui|xo)|mc(01|21|ca)|m\-cr|me(rc|ri)|mi(o8|oa|ts)|mmef|mo(01|02|bi|de|do|t(\-| |o|v)|zz)|mt(50|p1|v )|mwbp|mywa|n10[0-2]|n20[2-3]|n30(0|2)|n50(0|2|5)|n7(0(0|1)|10)|ne((c|m)\-|on|tf|wf|wg|wt)|nok(6|i)|nzph|o2im|op(ti|wv)|oran|owg1|p800|pan(a|d|t)|pdxg|pg(13|\-([1-8]|c))|phil|pire|pl(ay|uc)|pn\-2|po(ck|rt|se)|prox|psio|pt\-g|qa\-a|qc(07|12|21|32|60|\-[2-7]|i\-)|qtek|r380|r600|raks|rim9|ro(ve|zo)|s55\/|sa(ge|ma|mm|ms|ny|va)|sc(01|h\-|oo|p\-)|sdk\/|se(c(\-|0|1)|47|mc|nd|ri)|sgh\-|shar|sie(\-|m)|sk\-0|sl(45|id)|sm(al|ar|b3|it|t5)|so(ft|ny)|sp(01|h\-|v\-|v )|sy(01|mb)|t2(18|50)|t6(00|10|18)|ta(gt|lk)|tcl\-|tdg\-|tel(i|m)|tim\-|t\-mo|to(pl|sh)|ts(70|m\-|m3|m5)|tx\-9|up(\.b|g1|si)|utst|v400|v750|veri|vi(rg|te)|vk(40|5[0-3]|\-v)|vm40|voda|vulc|vx(52|53|60|61|70|80|81|83|85|98)|w3c(\-| )|webc|whit|wi(g |nc|nw)|wmlb|wonu|x700|yas\-|your|zeto|zte\-/i.test(a.substr(0,4))) check = true;})(navigator.userAgent||navigator.vendor||window.opera);

return check;   
}

How to prevent scanf causing a buffer overflow in C?

In their book The Practice of Programming (which is well worth reading), Kernighan and Pike discuss this problem, and they solve it by using snprintf() to create the string with the correct buffer size for passing to the scanf() family of functions. In effect:

int scanner(const char *data, char *buffer, size_t buflen)
{
    char format[32];
    if (buflen == 0)
        return 0;
    snprintf(format, sizeof(format), "%%%ds", (int)(buflen-1));
    return sscanf(data, format, buffer);
}

Note, this still limits the input to the size provided as 'buffer'. If you need more space, then you have to do memory allocation, or use a non-standard library function that does the memory allocation for you.


Note that the POSIX 2008 (2013) version of the scanf() family of functions supports a format modifier m (an assignment-allocation character) for string inputs (%s, %c, %[). Instead of taking a char * argument, it takes a char ** argument, and it allocates the necessary space for the value it reads:

char *buffer = 0;
if (sscanf(data, "%ms", &buffer) == 1)
{
    printf("String is: <<%s>>\n", buffer);
    free(buffer);
}

If the sscanf() function fails to satisfy all the conversion specifications, then all the memory it allocated for %ms-like conversions is freed before the function returns.

Is Ruby pass by reference or by value?

Is Ruby pass by reference or by value?

Ruby is pass-by-reference. Always. No exceptions. No ifs. No buts.

Here is a simple program which demonstrates that fact:

def foo(bar)
  bar.object_id
end

baz = 'value'

puts "#{baz.object_id} Ruby is pass-by-reference #{foo(baz)} because object_id's (memory addresses) are always the same ;)"

=> 2279146940 Ruby is pass-by-reference 2279146940 because object_id's (memory addresses) are always the same ;)

def bar(babar)
  babar.replace("reference")
end

bar(baz)

puts "some people don't realize it's reference because local assignment can take precedence, but it's clearly pass-by-#{baz}"

=> some people don't realize it's reference because local assignment can take precedence, but it's clearly pass-by-reference

Macro to Auto Fill Down to last adjacent cell

Untested....but should work.

Dim lastrow as long

lastrow = range("D65000").end(xlup).Row

ActiveCell.FormulaR1C1 = _
        "=IF(MONTH(RC[-1])>3,"" ""&YEAR(RC[-1])&""-""&RIGHT(YEAR(RC[-1])+1,2),"" ""&YEAR(RC[-1])-1&""-""&RIGHT(YEAR(RC[-1]),2))"
    Selection.AutoFill Destination:=Range("E2:E" & lastrow)
    'Selection.AutoFill Destination:=Range("E2:E"& lastrow)
    Range("E2:E1344").Select

Only exception being are you sure your Autofill code is perfect...

Filter an array using a formula (without VBA)

Sounds like you're just trying to do a classic two-column lookup. http://www.dailydoseofexcel.com/archives/2009/04/21/vlookup-on-two-columns/

Tons of solutions for this, most simple is probably the following (which doesn't require an array formula):

=SUMPRODUCT((Lookup!A:A=Param!A1)*(Lookup!B:B=Param!B1)*(Lookup!C:C))

To translate your specific example, you would use:

=SUMPRODUCT((A1:A3=A2)*(B1:B3="B")*(C1:C3))

How to find if a given key exists in a C++ std::map

m.find == m.end() // not found 

If you want to use other API, then find go for m.count(c)>0

 if (m.count("f")>0)
      cout << " is an element of m.\n";
    else 
      cout << " is not an element of m.\n";

Where are the python modules stored?

On Windows machine python modules are located at (system drive and python version may vary):

C:\Users\Administrator\AppData\Local\Programs\Python\Python38\Lib

How can I increase the JVM memory?

Right click on project -> Run As -> Run Configurations..-> Select Arguments tab -> In VM Arguments you can increase your JVM memory allocation. Java HotSpot document will help you to setup your VM Argument HERE

I will not prefer to make any changes into eclipse.ini as minor mistake cause lot of issues. It's easier to play with VM Args

angularjs - ng-repeat: access key and value from JSON array object

Solution I have json object which has data

[{"name":"Ata","email":"[email protected]"}]

You can use following approach to iterate through ng-repeat and use table format instead of list.

<div class="container" ng-controller="fetchdataCtrl">    
  <ul ng-repeat="item in numbers">
    <li>            
      {{item.name}}: {{item.email}}
    </li>
  </ul>     
</div>

how to convert a string to an array in php

here, Use explode() function to convert string into array, by a string

click here to know more about explode()

$str = "this is string";
$delimiter = ' ';  // use any string / character by which, need to split string into Array
$resultArr = explode($delimiter, $str);  
var_dump($resultArr);

Output :

Array
(
    [0] => "this",
    [1] => "is",
    [2] => "string "
)

it is same as the requirements:

  arr[0]="this";
  arr[1]="is";
  arr[2]="string";

set div height using jquery (stretch div height)

The correct way to do this is with good-old CSS:

#content{
    width:100%;
    position:absolute;
    top:35px;
    bottom:35px;
}

And the bonus is that you don't need to attach to the window.onresize event! Everything will adjust as the document reflows. All for the low-low price of four lines of CSS!

How can I use grep to show just filenames on Linux?

From the grep(1) man page:

  -l, --files-with-matches
          Suppress  normal  output;  instead  print the name of each input
          file from which output would normally have  been  printed.   The
          scanning  will  stop  on  the  first match.  (-l is specified by
          POSIX.)

check if a file is open in Python

If all you care about is the current process, an easy way is to use the file object attribute "closed"

f = open('file.py')
if f.closed:
  print 'file is closed'

This will not detect if the file is open by other processes!

source: http://docs.python.org/2.4/lib/bltin-file-objects.html

Scanner is never closed

I am assuming you are using java 7, thus you get a compiler warning, when you don't close the resource you should close your scanner usually in a finally block.

Scanner scanner = null;
try {
    scanner = new Scanner(System.in);
    //rest of the code
}
finally {
    if(scanner!=null)
        scanner.close();
}

Or even better: use the new Try with resource statement:

try(Scanner scanner = new Scanner(System.in)){
    //rest of your code
}

How to set thymeleaf th:field value from other variable

The correct approach is to use preprocessing

For example

th:field="*{__${myVar}__}"

How to generate a core dump in Linux on a segmentation fault?

Ubuntu 19.04

All other answers themselves didn't help me. But the following sum up did the job

Create ~/.config/apport/settings with the following content:

[main]
unpackaged=true

(This tells apport to also write core dumps for custom apps)

check: ulimit -c. If it outputs 0, fix it with

ulimit -c unlimited

Just for in case restart apport:

sudo systemctl restart apport

Crash files are now written in /var/crash/. But you cannot use them with gdb. To use them with gdb, use

apport-unpack <location_of_report> <target_directory>

Further information:

  • Some answers suggest changing core_pattern. Be aware, that that file might get overwritten by the apport service on restarting.
  • Simply stopping apport did not do the job
  • The ulimit -c value might get changed automatically while you're trying other answers of the web. Be sure to check it regularly during setting up your core dump creation.

References:

How do I install a module globally using npm?

If you want to install a npm module globally, make sure to use the new -g flag, for example:

npm install forever -g

The general recommendations concerning npm module installation since 1.0rc (taken from blog.nodejs.org):

  • If you’re installing something that you want to use in your program, using require('whatever'), then install it locally, at the root of your project.
  • If you’re installing something that you want to use in your shell, on the command line or something, install it globally, so that its binaries end up in your PATH environment variable.

I just recently used this recommendations and it went down pretty smoothly. I installed forever globally (since it is a command line tool) and all my application modules locally.

However, if you want to use some modules globally (i.e. express or mongodb), take this advice (also taken from blog.nodejs.org):

Of course, there are some cases where you want to do both. Coffee-script and Express both are good examples of apps that have a command line interface, as well as a library. In those cases, you can do one of the following:

  • Install it in both places. Seriously, are you that short on disk space? It’s fine, really. They’re tiny JavaScript programs.
  • Install it globally, and then npm link coffee-script or npm link express (if you’re on a platform that supports symbolic links.) Then you only need to update the global copy to update all the symlinks as well.

The first option is the best in my opinion. Simple, clear, explicit. The second is really handy if you are going to re-use the same library in a bunch of different projects. (More on npm link in a future installment.)

I did not test one of those variations, but they seem to be pretty straightforward.

How to get a reversed list view on a list in Java?

You can also invert the position when you request an object:

Object obj = list.get(list.size() - 1 - position);

What is this spring.jpa.open-in-view=true property in Spring Boot?

The OSIV Anti-Pattern

Instead of letting the business layer decide how it’s best to fetch all the associations that are needed by the View layer, OSIV (Open Session in View) forces the Persistence Context to stay open so that the View layer can trigger the Proxy initialization, as illustrated by the following diagram.

enter image description here

  • The OpenSessionInViewFilter calls the openSession method of the underlying SessionFactory and obtains a new Session.
  • The Session is bound to the TransactionSynchronizationManager.
  • The OpenSessionInViewFilter calls the doFilter of the javax.servlet.FilterChain object reference and the request is further processed
  • The DispatcherServlet is called, and it routes the HTTP request to the underlying PostController.
  • The PostController calls the PostService to get a list of Post entities.
  • The PostService opens a new transaction, and the HibernateTransactionManager reuses the same Session that was opened by the OpenSessionInViewFilter.
  • The PostDAO fetches the list of Post entities without initializing any lazy association.
  • The PostService commits the underlying transaction, but the Session is not closed because it was opened externally.
  • The DispatcherServlet starts rendering the UI, which, in turn, navigates the lazy associations and triggers their initialization.
  • The OpenSessionInViewFilter can close the Session, and the underlying database connection is released as well.

At first glance, this might not look like a terrible thing to do, but, once you view it from a database perspective, a series of flaws start to become more obvious.

The service layer opens and closes a database transaction, but afterward, there is no explicit transaction going on. For this reason, every additional statement issued from the UI rendering phase is executed in auto-commit mode. Auto-commit puts pressure on the database server because each transaction issues a commit at end, which can trigger a transaction log flush to disk. One optimization would be to mark the Connection as read-only which would allow the database server to avoid writing to the transaction log.

There is no separation of concerns anymore because statements are generated both by the service layer and by the UI rendering process. Writing integration tests that assert the number of statements being generated requires going through all layers (web, service, DAO) while having the application deployed on a web container. Even when using an in-memory database (e.g. HSQLDB) and a lightweight webserver (e.g. Jetty), these integration tests are going to be slower to execute than if layers were separated and the back-end integration tests used the database, while the front-end integration tests were mocking the service layer altogether.

The UI layer is limited to navigating associations which can, in turn, trigger N+1 query problems. Although Hibernate offers @BatchSize for fetching associations in batches, and FetchMode.SUBSELECT to cope with this scenario, the annotations are affecting the default fetch plan, so they get applied to every business use case. For this reason, a data access layer query is much more suitable because it can be tailored to the current use case data fetch requirements.

Last but not least, the database connection is held throughout the UI rendering phase which increases connection lease time and limits the overall transaction throughput due to congestion on the database connection pool. The more the connection is held, the more other concurrent requests are going to wait to get a connection from the pool.

Spring Boot and OSIV

Unfortunately, OSIV (Open Session in View) is enabled by default in Spring Boot, and OSIV is really a bad idea from a performance and scalability perspective.

So, make sure that in the application.properties configuration file, you have the following entry:

spring.jpa.open-in-view=false

This will disable OSIV so that you can handle the LazyInitializationException the right way.

Starting with version 2.0, Spring Boot issues a warning when OSIV is enabled by default, so you can discover this problem long before it affects a production system.

How do I assign a port mapping to an existing Docker container?

I'm also interested in this problem.

As @Thasmo mentioned, port forwardings can be specified ONLY with docker run (and docker create) command.
Other commands, docker start does not have -p option and docker port only displays current forwardings.

To add port forwardings, I always follow these steps,

  1. stop running container

    docker stop test01
    
  2. commit the container

    docker commit test01 test02
    

    NOTE: The above, test02 is a new image that I'm constructing from the test01 container.

  3. re-run from the commited image

    docker run -p 8080:8080 -td test02
    

Where the first 8080 is the local port and the second 8080 is the container port.

How to change the name of an iOS app?

You change the bundle display name in the info.plist. It's as simple as that.

Changing the 'bundle display name' (as opposed to 'bundle name') is the only way to include characters like '+' in your applications name. Including special characters in the project name will cause an error when uploading to the app store!

POST JSON to API using Rails and HTTParty

I solved this by adding .to_json and some heading information

@result = HTTParty.post(@urlstring_to_post.to_str, 
    :body => { :subject => 'This is the screen name', 
               :issue_type => 'Application Problem', 
               :status => 'Open', 
               :priority => 'Normal', 
               :description => 'This is the description for the problem'
             }.to_json,
    :headers => { 'Content-Type' => 'application/json' } )

unknown error: Chrome failed to start: exited abnormally (Driver info: chromedriver=2.9

In Linux adding these lines to my code helped me.

from selenium import webdriver
from selenium.webdriver.chrome.options import Options


chrome_options = Options()
chrome_options.add_argument("--disable-extensions")
chrome_options.add_argument("--disable-gpu")
chrome_options.add_argument("--no-sandbox")
driver = webdriver.Chrome(options=chrome_options)

driver.get("www.counterviews.online")

jQuery Scroll To bottom of the page

$("div").scrollTop(1000);

Works for me. Scrolls to the bottom.

How can I use UserDefaults in Swift?

In class A, set value for key:

let text = "hai"  
UserDefaults.standard.setValue(text, forKey: "textValue")

In class B, get the value for the text using the key which declared in class A and assign it to respective variable which you need:

var valueOfText  = UserDefaults.value(forKey: "textValue")

What is the difference between a deep copy and a shallow copy?

char * Source = "Hello, world.";

char * ShallowCopy = Source;    

char * DeepCopy = new char(strlen(Source)+1);
strcpy(DeepCopy,Source);        

'ShallowCopy' points to the same location in memory as 'Source' does. 'DeepCopy' points to a different location in memory, but the contents are the same.

Convert a JSON String to a HashMap

Brief and Useful:

/**
 * @param jsonThing can be a <code>JsonObject</code>, a <code>JsonArray</code>,
 *                     a <code>Boolean</code>, a <code>Number</code>,
 *                     a <code>null</code> or a <code>JSONObject.NULL</code>.
 * @return <i>Appropriate Java Object</i>, that may be a <code>Map</code>, a <code>List</code>,
 * a <code>Boolean</code>, a <code>Number</code> or a <code>null</code>.
 */
public static Object jsonThingToAppropriateJavaObject(Object jsonThing) throws JSONException {
    if (jsonThing instanceof JSONArray) {
        final ArrayList<Object> list = new ArrayList<>();

        final JSONArray jsonArray = (JSONArray) jsonThing;
        final int l = jsonArray.length();
        for (int i = 0; i < l; ++i) list.add(jsonThingToAppropriateJavaObject(jsonArray.get(i)));
        return list;
    }

    if (jsonThing instanceof JSONObject) {
        final HashMap<String, Object> map = new HashMap<>();

        final Iterator<String> keysItr = ((JSONObject) jsonThing).keys();
        while (keysItr.hasNext()) {
            final String key = keysItr.next();
            map.put(key, jsonThingToAppropriateJavaObject(((JSONObject) jsonThing).get(key)));
        }
        return map;
    }

    if (JSONObject.NULL.equals(jsonThing)) return null;

    return jsonThing;
}

Thank @Vikas Gupta.

Run jar file in command prompt

Try this

java -jar <jar-file-name>.jar

Adding an onclick function to go to url in JavaScript?

Simply use this

onclick="location.href='pageurl.html';"

Include an SVG (hosted on GitHub) in MarkDown

Update 2020: how they made it work while avoiding XSS attacks

GitHub appears to use two security approaches, this is a good article: https://digi.ninja/blog/svg_xss.php see also: https://security.stackexchange.com/questions/148507/how-to-prevent-xss-in-svg-file-upload

Update 2017

A GitHub dev is currently looking into this: https://github.com/github/markup/issues/556#issuecomment-306103203

Update 2014-12: GitHub now renders SVG on blob show, so I don't see any reason why not to render on README renderings:

Also note that that SVG does have an XSS attempt but it does not run: https://raw.githubusercontent.com/cirosantilli/test/2144a93333be144152e8b0d4144b77b211afce63/svg.svg

The billion laugh SVG does make Firefox 44 Freeze, but Chromium 48 is OK: https://github.com/cirosantilli/web-cheat/blob/master/svg-billion-laughs.svg

Petah mentioned that blobs are fine because the SVG is inside an iframe.

Possible rationale for GitHub not serving SVG images

The following questions asks about the risks of SVG in general: https://security.stackexchange.com/questions/11384/exploits-or-other-security-risks-with-svg-upload

How to keep indent for second line in ordered lists via CSS?

The following CSS did the trick:

ul{
    margin-left: 1em;
}

li{
    list-style-position: outside;
    padding-left: 0.5em;
}

What is the worst real-world macros/pre-processor abuse you've ever come across?

I like this example, it uses the macro to approximate the value of PI. The larger the circle, the more accurate the approximation.

#define _ -F<00||--F-OO--;
int F=00,OO=00;main(){F_OO();printf("%1.3f\n",4.*-F/OO/OO);}F_OO()
{
            _-_-_-_
       _-_-_-_-_-_-_-_-_
    _-_-_-_-_-_-_-_-_-_-_-_
  _-_-_-_-_-_-_-_-_-_-_-_-_-_
 _-_-_-_-_-_-_-_-_-_-_-_-_-_-_
 _-_-_-_-_-_-_-_-_-_-_-_-_-_-_
_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_
_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_
_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_
_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_
 _-_-_-_-_-_-_-_-_-_-_-_-_-_-_
 _-_-_-_-_-_-_-_-_-_-_-_-_-_-_
  _-_-_-_-_-_-_-_-_-_-_-_-_-_
    _-_-_-_-_-_-_-_-_-_-_-_
        _-_-_-_-_-_-_-_
            _-_-_-_
}

Another is the c program

c

To compile you need to define c as

-Dc="#include <stdio.h> int main() { char *t =\"Hello World\n\"; while(*t) putc(*t++, stdout); return 0; }"

How to return multiple values?

You can return an object of a Class in Java.

If you are returning more than 1 value that are related, then it makes sense to encapsulate them into a class and then return an object of that class.

If you want to return unrelated values, then you can use Java's built-in container classes like Map, List, Set etc. Check the java.util package's JavaDoc for more details.

Can angularjs routes have optional parameter values?

Please see @jlareau answer here: https://stackoverflow.com/questions/11534710/angularjs-how-to-use-routeparams-in-generating-the-templateurl

You can use a function to generate the template string:

var app = angular.module('app',[]);

app.config(
    function($routeProvider) {
        $routeProvider.
            when('/', {templateUrl:'/home'}).
            when('/users/:user_id', 
                {   
                    controller:UserView, 
                    templateUrl: function(params){ return '/users/view/' + params.user_id;   }
                }
            ).
            otherwise({redirectTo:'/'});
    }
);

Best way to find the months between two dates

Start by defining some test cases, then you will see that the function is very simple and needs no loops

from datetime import datetime

def diff_month(d1, d2):
    return (d1.year - d2.year) * 12 + d1.month - d2.month

assert diff_month(datetime(2010,10,1), datetime(2010,9,1)) == 1
assert diff_month(datetime(2010,10,1), datetime(2009,10,1)) == 12
assert diff_month(datetime(2010,10,1), datetime(2009,11,1)) == 11
assert diff_month(datetime(2010,10,1), datetime(2009,8,1)) == 14

You should add some test cases to your question, as there are lots of potential corner cases to cover - there is more than one way to define the number of months between two dates.

Change UITableView height dynamically

Use simple and easy code

func tableView(tableView: UITableView, heightForRowAtIndexPath indexPath: NSIndexPath) -> CGFloat {
        let myCell = tableView.dequeueReusableCellWithIdentifier("mannaCustumCell") as! CustomCell
        let heightForCell = myCell.bounds.size.height;

        return heightForCell;
    }

No connection could be made because the target machine actively refused it 127.0.0.1

If you have config file transforms then ensure you have the correct config selected within your publish profile. (Publish > Settings > Configuration)

Dropdownlist width in IE

A full fledged jQuery plugin is available. It supports non-breaking layout and keyboard interactions, check out the demo page: http://powerkiki.github.com/ie_expand_select_width/

disclaimer: I coded that thing, patches welcome

How can I strip first and last double quotes?

If the quotes you want to strip are always going to be "first and last" as you said, then you could simply use:

string = string[1:-1]

How to customize the background color of a UITableViewCell?

You need to set the backgroundColor of the cell's contentView to your color. If you use accessories (such as disclosure arrows, etc), they'll show up as white, so you may need to roll custom versions of those.

How to print (using cout) a number in binary form?

Is this what you're looking for?

std::cout << std::hex << val << std::endl;

How do you print in Sublime Text 2

There is also the Simple Print package, which uses enscript to do the actual printing.

Similar to kenorb's answer, open the palette (ctrl/cmd+shift+p), "Install package", "Simple Print Function"

you MUST install enscript and here is how:

https://github.com/svenax/SublimePrint

How to read until EOF from cin in C++

Using loops:

#include <iostream>
using namespace std;
...
// numbers
int n;
while (cin >> n)
{
   ...
}
// lines
string line;
while (getline(cin, line))
{
   ...
}
// characters
char c;
while (cin.get(c))
{
   ...
}

resource

How to convert an iterator to a stream?

Another way to do this on Java 9+ using Stream::iterate(T, Predicate, UnaryOperator):

Stream.iterate(iterator, Iterator::hasNext, UnaryOperator.identity())
        .map(Iterator::next)
        .forEach(System.out::println);

Difference between Iterator and Listiterator?

There are two differences:

  1. We can use Iterator to traverse Set and List and also Map type of Objects. While a ListIterator can be used to traverse for List-type Objects, but not for Set-type of Objects.

    That is, we can get a Iterator object by using Set and List, see here:

    By using Iterator we can retrieve the elements from Collection Object in forward direction only.

    Methods in Iterator:

    1. hasNext()
    2. next()
    3. remove()
    Iterator iterator = Set.iterator();
    Iterator iterator = List.iterator();
  2. But we get ListIterator object only from the List interface, see here:

    where as a ListIterator allows you to traverse in either directions (Both forward and backward). So it has two more methods like hasPrevious() and previous() other than those of Iterator. Also, we can get indexes of the next or previous elements (using nextIndex() and previousIndex() respectively )

    Methods in ListIterator:

    1. hasNext()
    2. next()
    3. previous()
    4. hasPrevious()
    5. remove()
    6. nextIndex()
    7. previousIndex()
    ListIterator listiterator = List.listIterator();

    i.e., we can't get ListIterator object from Set interface.

Reference : - What is the difference between Iterator and ListIterator ?

CSS: Center block, but align contents to the left

First, create a parent div that centers its child content with text-align: center. Next, create a child div that uses display: inline-block to adapt to the width of its children and text-align: left to make the content it holds align to the left as desired.

_x000D_
_x000D_
<div style="text-align: center;">_x000D_
    <div style="display: inline-block; text-align: left;">_x000D_
        Centered<br />_x000D_
        Content<br />_x000D_
        That<br />_x000D_
        Is<br />_x000D_
        Left<br />_x000D_
        Aligned_x000D_
    </div>_x000D_
</div>
_x000D_
_x000D_
_x000D_

Getting a list item by index

Visual Basic, C#, and C++ all have syntax for accessing the Item property without using its name. Instead, the variable containing the List is used as if it were an array.

List[index]

See for instance: https://msdn.microsoft.com/en-us/library/0ebtbkkc(v=vs.110).aspx

Get name of current script in Python

If you're doing an unusual import (e.g., it's an options file), try:

import inspect
print (inspect.getfile(inspect.currentframe()))

Note that this will return the absolute path to the file.

Static Initialization Blocks

There are a few actual reasons that it is required to exist:

  1. initializing static final members whose initialization might throw an exception
  2. initializing static final members with calculated values

People tend to use static {} blocks as a convenient way to initialize things that the class depends on within the runtime as well - such as ensuring that particular class is loaded (e.g., JDBC drivers). That can be done in other ways; however, the two things that I mention above can only be done with a construct like the static {} block.

Scala list concatenation, ::: vs ++

A different point is that the first sentence is parsed as:

scala> List(1,2,3).++(List(4,5))
res0: List[Int] = List(1, 2, 3, 4, 5)

Whereas the second example is parsed as:

scala> List(4,5).:::(List(1,2,3))
res1: List[Int] = List(1, 2, 3, 4, 5)

So if you are using macros, you should take care.

Besides, ++ for two lists is calling ::: but with more overhead because it is asking for an implicit value to have a builder from List to List. But microbenchmarks did not prove anything useful in that sense, I guess that the compiler optimizes such calls.

Micro-Benchmarks after warming up.

scala>def time(a: => Unit): Long = { val t = System.currentTimeMillis; a; System.currentTimeMillis - t}
scala>def average(a: () => Long) = (for(i<-1 to 100) yield a()).sum/100

scala>average (() => time { (List[Int]() /: (1 to 1000)) { case (l, e) => l ++ List(e) } })
res1: Long = 46
scala>average (() => time { (List[Int]() /: (1 to 1000)) { case (l, e) => l ::: List(e ) } })
res2: Long = 46

As Daniel C. Sobrai said, you can append the content of any collection to a list using ++, whereas with ::: you can only concatenate lists.

How to install wget in macOS?

You need to do

./configure --with-ssl=openssl --with-libssl-prefix=/usr/local/ssl

Instead of this

./configure --with-ssl=openssl

Visual Studio setup problem - 'A problem has been encountered while loading the setup components. Canceling setup.'

Windows 7 suggested to "Uninstall using recommended settings" after hitting OK in the error message. It solved the problem.

Get a list of checked checkboxes in a div using jQuery

This works for me.

var selecteditems = [];

$("#Div").find("input:checked").each(function (i, ob) { 
    selecteditems.push($(ob).val());
});

Docker: How to delete all local Docker images

docker rmi $(docker images -q) --force

Angular Directive refresh on parameter change

angular.module('app').directive('conversation', function() {
    return {
        restrict: 'E',
        link: function ($scope, $elm, $attr) {
            $scope.$watch("some_prop", function (newValue, oldValue) {
                  var typeId = $attr.type-id;
                  // Your logic.
            });
        }
    };
}

Injection of autowired dependencies failed;

The error shows that com.bd.service.ArticleService is not a registered bean. Add the packages in which you have beans that will be autowired in your application context:

<context:component-scan base-package="com.bd.service"/>
<context:component-scan base-package="com.bd.controleur"/>

Alternatively, if you want to include all subpackages in com.bd:

<context:component-scan base-package="com.bd">
     <context:include-filter type="aspectj" expression="com.bd.*" />
</context:component-scan>

As a side note, if you're using Spring 3.1 or later, you can take advantage of the @ComponentScan annotation, so that you don't have to use any xml configuration regarding component-scan. Use it in conjunction with @Configuration.

@Controller
@RequestMapping("/Article/GererArticle")
@Configuration
@ComponentScan("com.bd.service") // No need to include component-scan in xml
public class ArticleControleur {

    @Autowired
    ArticleService articleService;
    ...
}

You might find this Spring in depth section on Autowiring useful.

How to fix request failed on channel 0

I occasionally see this when spinning up a VM. Our automation system starts applying updates, so depending on timing can hit an update to critical packages.

Upshot - this might happen if ssh or other related packages are being updated on the destination machine.

How to catch and print the full exception traceback without halting/exiting the program?

traceback.format_exception

If you only have the exception object, you can get the traceback as a string from any point of the code in Python 3 with:

import traceback

''.join(traceback.format_exception(None, exc_obj, exc_obj.__traceback__))

Full example:

#!/usr/bin/env python3

import traceback

def f():
    g()

def g():
    raise Exception('asdf')

try:
    g()
except Exception as e:
    exc = e

tb_str = ''.join(traceback.format_exception(None, exc_obj, exc_obj.__traceback__))
print(tb_str)

Output:

Traceback (most recent call last):
  File "./main.py", line 12, in <module>
    g()
  File "./main.py", line 9, in g
    raise Exception('asdf')
Exception: asdf

Documentation: https://docs.python.org/3.7/library/traceback.html#traceback.format_exception

See also: Extract traceback info from an exception object

Tested in Python 3.7.3.

SQL Server Group by Count of DateTime Per Hour?

Alternatively, just GROUP BY the hour and day:

SELECT  CAST(Startdate as DATE) as 'StartDate', 
        CAST(DATEPART(Hour, StartDate) as varchar) + ':00' as 'Hour', 
        COUNT(*) as 'Ct'
FROM #Events
GROUP BY CAST(Startdate as DATE), DATEPART(Hour, StartDate)
ORDER BY CAST(Startdate as DATE) ASC

output:

StartDate   Hour    Ct
2007-01-01  0:00    3
2007-01-02  5:00    2
2007-01-03  4:00    1
2007-01-07  3:00    1

Java - how do I write a file to a specified directory

You should use the secondary constructor for File to specify the directory in which it is to be symbolically created. This is important because the answers that say to create a file by prepending the directory name to original name, are not as system independent as this method.

Sample code:

String dirName = /* something to pull specified dir from input */;

String fileName = "test.txt";
File dir = new File (dirName);
File actualFile = new File (dir, fileName);

/* rest is the same */

Hope it helps.

Why does dividing two int not yield the right value when assigned to double?

For the same reasons above, you'll have to convert one of 'a' or 'b' to a double type. Another way of doing it is to use:

double c = (a+0.0)/b;

The numerator is (implicitly) converted to a double because we have added a double to it, namely 0.0.

How to append text to an existing file in Java?

In Java-7 it also can be done such kind:

import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.nio.file.StandardOpenOption;

//---------------------

Path filePath = Paths.get("someFile.txt");
if (!Files.exists(filePath)) {
    Files.createFile(filePath);
}
Files.write(filePath, "Text to be added".getBytes(), StandardOpenOption.APPEND);

UIView's frame, bounds, center, origin, when to use what?

The properties center, bounds and frame are interlocked: changing one will update the others, so use them however you want. For example, instead of modifying the x/y params of frame to recenter a view, just update the center property.

How do you allow spaces to be entered using scanf?

getline()

Now part of POSIX, none-the-less.

It also takes care of the buffer allocation problem that you asked about earlier, though you have to take care of freeing the memory.

Getting DOM node from React child element

I found an easy way using the new callback refs. You can just pass a callback as a prop to the child component. Like this:

class Container extends React.Component {
  constructor(props) {
    super(props)
    this.setRef = this.setRef.bind(this)
  }

  setRef(node) {
    this.childRef = node
  }

  render() {
    return <Child setRef={ this.setRef }/>
  }
}

const Child = ({ setRef }) => (
    <div ref={ setRef }>
    </div>
)

Here's an example of doing this with a modal:

class Container extends React.Component {
  constructor(props) {
    super(props)
    this.state = {
      modalOpen: false
    }
    this.open = this.open.bind(this)
    this.close = this.close.bind(this)
    this.setModal = this.setModal.bind(this)
  }

  open() {
    this.setState({ open: true })
  }

  close(event) {
    if (!this.modal.contains(event.target)) {
      this.setState({ open: false })
    }
  }

  setModal(node) {
    this.modal = node
  }

  render() {
    let { modalOpen } = this.state
    return (
      <div>
        <button onClick={ this.open }>Open</button>
        {
          modalOpen ? <Modal close={ this.close } setModal={ this.setModal }/> : null
        }
      </div>
    )
  }
}

const Modal = ({ close, setModal }) => (
  <div className='modal' onClick={ close }>
    <div className='modal-window' ref={ setModal }>
    </div>
  </div>
)

What is "Linting"?

Linting is a process by a linter program that analyzes source code in a particular programming language and flag potential problems like syntax errors, deviations from a prescribed coding style or using constructs known to be unsafe.

For example, a JavaScript linter would flag the first use of parseInt below as unsafe:

// without a radix argument - Unsafe
var count = parseInt(countString);

// with a radix paremeter specified - Safe
var count = parseInt(countString, 10);

How to run a cron job inside a docker container?

So, my problem was the same. The fix was to change the command section in the docker-compose.yml.

From

command: crontab /etc/crontab && tail -f /etc/crontab

To

command: crontab /etc/crontab

command: tail -f /etc/crontab

The problem was the '&&' between the commands. After deleting this, it was all fine.

CS0234: Mvc does not exist in the System.Web namespace

add Microsoft.AspNet.Mvc nuget package.

Foreach in a Foreach in MVC View

Assuming your controller's action method is something like this:

public ActionResult AllCategories(int id = 0)
{
    return View(db.Categories.Include(p => p.Products).ToList());
}

Modify your models to be something like this:

public class Product
{
    [Key]
    public int ID { get; set; }
    public int CategoryID { get; set; }
    //new code
    public virtual Category Category { get; set; }
    public string Title { get; set; }
    public string Description { get; set; }
    public string Path { get; set; }

    //remove code below
    //public virtual ICollection<Category> Categories { get; set; }
}

public class Category
{
    [Key]
    public int CategoryID { get; set; }
    public string Name { get; set; }
    //new code
    public virtual ICollection<Product> Products{ get; set; }
}

Then your since now the controller takes in a Category as Model (instead of a Product):

foreach (var category in Model)
{
    <h3><u>@category.Name</u></h3>
    <div>
        <ul>    
            @foreach (var product in Model.Products)
            {
                // cut for brevity, need to add back more code from original
                <li>@product.Title</li>
            }
        </ul>
    </div>
}

UPDATED: Add ToList() to the controller return statement.

CSS table-cell equal width

Here is a working fiddle with indeterminate number of cells: http://jsfiddle.net/r9yrM/1/

You can fix a width to each parent div (the table), otherwise it'll be 100% as usual.

The trick is to use table-layout: fixed; and some width on each cell to trigger it, here 2%. That will trigger the other table algorightm, the one where browsers try very hard to respect the dimensions indicated.
Please test with Chrome (and IE8- if needed). It's OK with a recent Safari but I can't remember the compatibility of this trick with them.

CSS (relevant instructions):

div {
    display: table;
    width: 250px;
    table-layout: fixed;
}

div > div {
    display: table-cell;
    width: 2%; /* or 100% according to OP comment. See edit about Safari 6 below */
}

EDIT (2013): Beware of Safari 6 on OS X, it has table-layout: fixed; wrong (or maybe just different, very different from other browsers. I didn't proof-read CSS2.1 REC table layout ;) ). Be prepared to different results.

Bootstrap 3 Glyphicons are not working

I just renamed the font from bootstrap.css using Ctrl+c, Ctrl+v and it worked.

Remove Null Value from String array in java

Quite similar approve as already posted above. However it's easier to read.

/**
 * Remove all empty spaces from array a string array
 * @param arr array
 * @return array without ""
 */
public static String[] removeAllEmpty(String[] arr) {
    if (arr == null)
        return arr;

    String[] result = new String[arr.length];
    int amountOfValidStrings = 0;

    for (int i = 0; i < arr.length; i++) {
        if (!arr[i].equals(""))
            result[amountOfValidStrings++] = arr[i];
    }

    result = Arrays.copyOf(result, amountOfValidStrings);

    return result;
}

Full examples of using pySerial package

Blog post Serial RS232 connections in Python

import time
import serial

# configure the serial connections (the parameters differs on the device you are connecting to)
ser = serial.Serial(
    port='/dev/ttyUSB1',
    baudrate=9600,
    parity=serial.PARITY_ODD,
    stopbits=serial.STOPBITS_TWO,
    bytesize=serial.SEVENBITS
)

ser.isOpen()

print 'Enter your commands below.\r\nInsert "exit" to leave the application.'

input=1
while 1 :
    # get keyboard input
    input = raw_input(">> ")
        # Python 3 users
        # input = input(">> ")
    if input == 'exit':
        ser.close()
        exit()
    else:
        # send the character to the device
        # (note that I happend a \r\n carriage return and line feed to the characters - this is requested by my device)
        ser.write(input + '\r\n')
        out = ''
        # let's wait one second before reading output (let's give device time to answer)
        time.sleep(1)
        while ser.inWaiting() > 0:
            out += ser.read(1)

        if out != '':
            print ">>" + out

Apache HttpClient Interim Error: NoHttpResponseException

Although accepted answer is right, but IMHO is just a workaround.

To be clear: it's a perfectly normal situation that a persistent connection may become stale. But unfortunately it's very bad when the HTTP client library cannot handle it properly.

Since this faulty behavior in Apache HttpClient was not fixed for many years, I definitely would prefer to switch to a library that can easily recover from a stale connection problem, e.g. OkHttp.

Why?

  1. OkHttp pools http connections by default.
  2. It gracefully recovers from situations when http connection becomes stale and request cannot be retried due to being not idempotent (e.g. POST). I cannot say it about Apache HttpClient (mentioned NoHttpResponseException).
  3. Supports HTTP/2.0 from early drafts and beta versions.

When I switched to OkHttp, my problems with NoHttpResponseException disappeared forever.

How to pass a variable to the SelectCommand of a SqlDataSource?

You need to define a valid type of SelectParameter. This MSDN article describes the various types and how to use them.

How do you return the column names of a table?

SELECT *
FROM INFORMATION_SCHEMA.COLUMNS
WHERE TABLE_NAME = N'TableName'

Error: unmappable character for encoding UTF8 during maven compilation

I too faced a similar issue and my resolution was different. I went to the line of code mentioned and traversed to the character (For SpanishTest.java[31, 81], go to 31st line and 81th character including spaces). I observed an apostrophe in comment which was causing the issue. Though not a mistake, the maven compiler reports issue and in my case it was possible to remove maven's 'illegal' character.. lol.

Insert a string at a specific index

You could prototype your own splice() into String.

Polyfill

if (!String.prototype.splice) {
    /**
     * {JSDoc}
     *
     * The splice() method changes the content of a string by removing a range of
     * characters and/or adding new characters.
     *
     * @this {String}
     * @param {number} start Index at which to start changing the string.
     * @param {number} delCount An integer indicating the number of old chars to remove.
     * @param {string} newSubStr The String that is spliced in.
     * @return {string} A new string with the spliced substring.
     */
    String.prototype.splice = function(start, delCount, newSubStr) {
        return this.slice(0, start) + newSubStr + this.slice(start + Math.abs(delCount));
    };
}

Example

_x000D_
_x000D_
String.prototype.splice = function(idx, rem, str) {_x000D_
    return this.slice(0, idx) + str + this.slice(idx + Math.abs(rem));_x000D_
};_x000D_
_x000D_
var result = "foo baz".splice(4, 0, "bar ");_x000D_
_x000D_
document.body.innerHTML = result; // "foo bar baz"
_x000D_
_x000D_
_x000D_


EDIT: Modified it to ensure that rem is an absolute value.

Does VBScript have a substring() function?

Yes, Mid.

Dim sub_str
sub_str = Mid(source_str, 10, 5)

The first parameter is the source string, the second is the start index, and the third is the length.

@bobobobo: Note that VBScript strings are 1-based, not 0-based. Passing 0 as an argument to Mid results in "invalid procedure call or argument Mid".

Remove all subviews?

For ios6 using autolayout I had to add a little bit of code to remove the constraints too.

NSMutableArray * constraints_to_remove = [ @[] mutableCopy] ;
for( NSLayoutConstraint * constraint in tagview.constraints) {
    if( [tagview.subviews containsObject:constraint.firstItem] ||
       [tagview.subviews containsObject:constraint.secondItem] ) {
        [constraints_to_remove addObject:constraint];
    }
}
[tagview removeConstraints:constraints_to_remove];

[ [tagview subviews] makeObjectsPerformSelector:@selector(removeFromSuperview)];

I'm sure theres a neater way to do this, but it worked for me. In my case I could not use a direct [tagview removeConstraints:tagview.constraints] as there were constraints set in XCode that were getting cleared.

how to resolve DTS_E_OLEDBERROR. in ssis

I had this same problem and it seemed to be related to using the same database connection for concurrent tasks. There might be some alternative solutions (maybe better), but I solved it by setting MaxConcurrentExecutables to 1.

How to deal with floating point number precision in JavaScript?

For the mathematically inclined: http://docs.oracle.com/cd/E19957-01/806-3568/ncg_goldberg.html

The recommended approach is to use correction factors (multiply by a suitable power of 10 so that the arithmetic happens between integers). For example, in the case of 0.1 * 0.2, the correction factor is 10, and you are performing the calculation:

> var x = 0.1
> var y = 0.2
> var cf = 10
> x * y
0.020000000000000004
> (x * cf) * (y * cf) / (cf * cf)
0.02

A (very quick) solution looks something like:

var _cf = (function() {
  function _shift(x) {
    var parts = x.toString().split('.');
    return (parts.length < 2) ? 1 : Math.pow(10, parts[1].length);
  }
  return function() { 
    return Array.prototype.reduce.call(arguments, function (prev, next) { return prev === undefined || next === undefined ? undefined : Math.max(prev, _shift (next)); }, -Infinity);
  };
})();

Math.a = function () {
  var f = _cf.apply(null, arguments); if(f === undefined) return undefined;
  function cb(x, y, i, o) { return x + f * y; }
  return Array.prototype.reduce.call(arguments, cb, 0) / f;
};

Math.s = function (l,r) { var f = _cf(l,r); return (l * f - r * f) / f; };

Math.m = function () {
  var f = _cf.apply(null, arguments);
  function cb(x, y, i, o) { return (x*f) * (y*f) / (f * f); }
  return Array.prototype.reduce.call(arguments, cb, 1);
};

Math.d = function (l,r) { var f = _cf(l,r); return (l * f) / (r * f); };

In this case:

> Math.m(0.1, 0.2)
0.02

I definitely recommend using a tested library like SinfulJS

Regarding 'main(int argc, char *argv[])'

The comp.lang.c FAQ deals with the question

"What's the correct declaration of main()?"
in Question 11.12a.

How to compare two dates in php

Not answering the OPs actual problem, but answering just the title. Since this is the top result for "comparing dates in php".

Pretty simple to use Datetime Objects (php >= 5.3.0) and Compare them directly

$date1 = new DateTime("2009-10-11");
$date2 = new DateTime("tomorrow"); // Can use date/string just like strtotime.
var_dump($date1 < $date2);

Where do I find the definition of size_t?

In minimalistic programs where a size_t definition was not loaded "by chance" in some include but I still need it in some context (for example to access std::vector<double>), then I use that context to extract the correct type. For example typedef std::vector<double>::size_type size_t.

(Surround with namespace {...} if necessary to make the scope limited.)

Error occurred during initialization of VM Could not reserve enough space for object heap Could not create the Java virtual machine

Eureka ! Finally I found a solution on this.

This is caused by Windows update that stops any 32-bit processes from consuming more than 1200 MB on a 64-bit machine. The only way you can repair this is by using the System Restore option on Win 7.

Start >> All Programs >> Accessories >> System Tools >> System Restore.

And then restore to a date on which your Java worked fine. This worked for me. What is surprising here is Windows still pushes system updates under the name of "Critical Updates" even when you disable all windows updates. ^&%)#* Windows :-)

git pull keeping local changes

Incase their is local uncommitted changes and avoid merge conflict while pulling.

git stash save
git pull
git stash pop

refer - https://happygitwithr.com/pull-tricky.html

Remove unwanted parts from strings in a column

I often use list comprehensions for these types of tasks because they're often faster.

There can be big differences in performance between the various methods for doing things like this (i.e. modifying every element of a series within a DataFrame). Often a list comprehension can be fastest - see code race below for this task:

import pandas as pd
#Map
data = pd.DataFrame({'time':['09:00','10:00','11:00','12:00','13:00'], 'result':['+52A','+62B','+44a','+30b','-110a']})
%timeit data['result'] = data['result'].map(lambda x: x.lstrip('+-').rstrip('aAbBcC'))
10000 loops, best of 3: 187 µs per loop
#List comprehension
data = pd.DataFrame({'time':['09:00','10:00','11:00','12:00','13:00'], 'result':['+52A','+62B','+44a','+30b','-110a']})
%timeit data['result'] = [x.lstrip('+-').rstrip('aAbBcC') for x in data['result']]
10000 loops, best of 3: 117 µs per loop
#.str
data = pd.DataFrame({'time':['09:00','10:00','11:00','12:00','13:00'], 'result':['+52A','+62B','+44a','+30b','-110a']})
%timeit data['result'] = data['result'].str.lstrip('+-').str.rstrip('aAbBcC')
1000 loops, best of 3: 336 µs per loop

Unable to create requested service [org.hibernate.engine.jdbc.env.spi.JdbcEnvironment]

I had this error with MySQL as my database and the only solution was reinstall all components of MySQL, because before I installed just the server.

So try to download other versions of PostgreSQL and get all the components

Adding items to an object through the .push() method

This is really easy: Example

//my object
var sendData = {field1:value1, field2:value2};

//add element
sendData['field3'] = value3;

How does Git handle symbolic links?

Git just stores the contents of the link (i.e. the path of the file system object that it links to) in a 'blob' just like it would for a normal file. It then stores the name, mode and type (including the fact that it is a symlink) in the tree object that represents its containing directory.

When you checkout a tree containing the link, it restores the object as a symlink regardless of whether the target file system object exists or not.

If you delete the file that the symlink references it doesn't affect the Git-controlled symlink in any way. You will have a dangling reference. It is up to the user to either remove or change the link to point to something valid if needed.

Sanitizing strings to make them URL and filename safe?

This is a good function:

public function getFriendlyURL($string) {
    setlocale(LC_CTYPE, 'en_US.UTF8');
    $string = iconv('UTF-8', 'ASCII//TRANSLIT//IGNORE', $string);
    $string = preg_replace('~[^\-\pL\pN\s]+~u', '-', $string);
    $string = str_replace(' ', '-', $string);
    $string = trim($string, "-");
    $string = strtolower($string);
    return $string;
} 

Checking for a null int value from a Java ResultSet

Another solution:

public class DaoTools {
    static public Integer getInteger(ResultSet rs, String strColName) throws SQLException {
        int nValue = rs.getInt(strColName);
        return rs.wasNull() ? null : nValue;
    }
}

How can I use NSError in my iPhone App?

Please refer following tutorial

i hope it will helpful for you but prior you have to read documentation of NSError

This is very interesting link i found recently ErrorHandling

Extract data from log file in specified range of time

Use grep and regular expressions, for example if you want 4 minutes interval of logs:

grep "31/Mar/2002:19:3[1-5]" logfile

will return all logs lines between 19:31 and 19:35 on 31/Mar/2002. Supposing you need the last 5 days starting from today 27/Sep/2011 you may use the following:

grep "2[3-7]/Sep/2011" logfile

How do I modify a MySQL column to allow NULL?

Your syntax error is caused by a missing "table" in the query

ALTER TABLE mytable MODIFY mycolumn varchar(255) null;

What's the difference between [ and [[ in Bash?

In bash, contrary to [, [[ prevents word splitting of variable values.

Check if element is visible in DOM

This is a way to determine it for all css properties including visibility:

html:

<div id="element">div content</div>

css:

#element
{
visibility:hidden;
}

javascript:

var element = document.getElementById('element');
 if(element.style.visibility == 'hidden'){
alert('hidden');
}
else
{
alert('visible');
}

It works for any css property and is very versatile and reliable.

.htaccess rewrite to redirect root URL to subdirectory

I was surprised that nobody mentioned this:

RedirectMatch ^/$ /store/

Basically, it redirects the root and only the root URL. The answer originated from this link

Java/Groovy - simple date reformatting

Your DateFormat pattern does not match you input date String. You could use

new SimpleDateFormat("dd-MMM-yyyy")

Removing a list of characters in string

Python 3, single line list comprehension implementation.

from string import ascii_lowercase # 'abcdefghijklmnopqrstuvwxyz'
def remove_chars(input_string, removable):
  return ''.join([_ for _ in input_string if _ not in removable])

print(remove_chars(input_string="Stack Overflow", removable=ascii_lowercase))
>>> 'S O'

Get month and year from a datetime in SQL Server 2005

That format doesn't exist. You need to do a combination of two things,

select convert(varchar(4),getdate(),100)  + convert(varchar(4),year(getdate()))

Why is 2 * (i * i) faster than 2 * i * i in Java?

More of an addendum. I did repro the experiment using the latest Java 8 JVM from IBM:

java version "1.8.0_191"
Java(TM) 2 Runtime Environment, Standard Edition (IBM build 1.8.0_191-b12 26_Oct_2018_18_45 Mac OS X x64(SR5 FP25))
Java HotSpot(TM) 64-Bit Server VM (build 25.191-b12, mixed mode)

And this shows very similar results:

0.374653912 s
n = 119860736
0.447778698 s
n = 119860736

(second results using 2 * i * i).

Interestingly enough, when running on the same machine, but using Oracle Java:

Java version "1.8.0_181"
Java(TM) SE Runtime Environment (build 1.8.0_181-b13)
Java HotSpot(TM) 64-Bit Server VM (build 25.181-b13, mixed mode)

results are on average a bit slower:

0.414331815 s
n = 119860736
0.491430656 s
n = 119860736

Long story short: even the minor version number of HotSpot matter here, as subtle differences within the JIT implementation can have notable effects.

What's the difference between getRequestURI and getPathInfo methods in HttpServletRequest?

I will put a small comparison table here (just to have it somewhere):

Servlet is mapped as /test%3F/* and the application is deployed under /app.

http://30thh.loc:8480/app/test%3F/a%3F+b;jsessionid=S%3F+ID?p+1=c+d&p+2=e+f#a

Method              URL-Decoded Result           
----------------------------------------------------
getContextPath()        no      /app
getLocalAddr()                  127.0.0.1
getLocalName()                  30thh.loc
getLocalPort()                  8480
getMethod()                     GET
getPathInfo()           yes     /a?+b
getProtocol()                   HTTP/1.1
getQueryString()        no      p+1=c+d&p+2=e+f
getRequestedSessionId() no      S%3F+ID
getRequestURI()         no      /app/test%3F/a%3F+b;jsessionid=S+ID
getRequestURL()         no      http://30thh.loc:8480/app/test%3F/a%3F+b;jsessionid=S+ID
getScheme()                     http
getServerName()                 30thh.loc
getServerPort()                 8480
getServletPath()        yes     /test?
getParameterNames()     yes     [p 2, p 1]
getParameter("p 1")     yes     c d

In the example above the server is running on the localhost:8480 and the name 30thh.loc was put into OS hosts file.

Comments

  • "+" is handled as space only in the query string

  • Anchor "#a" is not transferred to the server. Only the browser can work with it.

  • If the url-pattern in the servlet mapping does not end with * (for example /test or *.jsp), getPathInfo() returns null.

If Spring MVC is used

  • Method getPathInfo() returns null.

  • Method getServletPath() returns the part between the context path and the session ID. In the example above the value would be /test?/a?+b

  • Be careful with URL encoded parts of @RequestMapping and @RequestParam in Spring. It is buggy (current version 3.2.4) and is usually not working as expected.

Vertical dividers on horizontal UL menu

Quite and simple without any "having to specify the first element". CSS is more powerful than most think (e.g. the first-child:before is great!). But this is by far the cleanest and most proper way to do this, at least in my opinion it is.

#navigation ul
{
    margin: 0;
    padding: 0;
}

#navigation ul li
{
    list-style-type: none;
    display: inline;
}

#navigation li:not(:first-child):before {
    content: " | ";
}

Now just use a simple unordered list in HTML and it'll populate it for you. HTML should look like this:

<div id="navigation">
    <ul>
        <li><a href="#">Home</a></li>
        <li><a href="#">About Us</a></li>
        <li><a href="#">Support</a></li>
    </ul>
</div><!-- navigation -->

The result will be just like this:

HOME | ABOUT US | SUPPORT

Now you can indefinitely expand and never have to worry about order, changing links, or your first entry. It's all automated and works great!

CakePHP find method with JOIN

        $services = $this->Service->find('all', array(
            'limit' =>4,
            'fields' => array('Service.*','ServiceImage.*'),
            'joins' => array(
                array(
                        'table' => 'services_images',
                        'alias' => 'ServiceImage',
                        'type' => 'INNER',
                        'conditions' => array(
                        'ServiceImage.service_id' =>'Service.id'
                        )
                    ),
                ),
            )
        );

It goges to array is null.

How to add Action bar options menu in Android Fragments

in AndroidManifest.xml set theme holo like this:

<activity
android:name="your Fragment or activity"
android:label="@string/xxxxxx"
android:theme="@android:style/Theme.Holo" >

How can I pretty-print JSON using node.js?

JSON.stringify's third parameter defines white-space insertion for pretty-printing. It can be a string or a number (number of spaces). Node can write to your filesystem with fs. Example:

var fs = require('fs');

fs.writeFile('test.json', JSON.stringify({ a:1, b:2, c:3 }, null, 4));
/* test.json:
{
     "a": 1,
     "b": 2,
     "c": 3,
}
*/

See the JSON.stringify() docs at MDN, Node fs docs

Using both Python 2.x and Python 3.x in IPython Notebook

These instructions explain how to install a python2 and python3 kernel in separate virtual environments for non-anaconda users. If you are using anaconda, please find my other answer for a solution directly tailored to anaconda.

I assume that you already have jupyter notebook installed.


First make sure that you have a python2 and a python3 interpreter with pip available.

On ubuntu you would install these by:

sudo apt-get install python-dev python3-dev python-pip python3-pip

Next prepare and register the kernel environments

python -m pip install virtualenv --user

# configure python2 kernel
python -m virtualenv -p python2 ~/py2_kernel
source ~/py2_kernel/bin/activate
python -m pip install ipykernel
ipython kernel install --name py2 --user
deactivate

# configure python3 kernel
python -m virtualenv -p python3 ~/py3_kernel
source ~/py3_kernel/bin/activate
python -m pip install ipykernel
ipython kernel install --name py3 --user
deactivate

To make things easier, you may want to add shell aliases for the activation command to your shell config file. Depending on the system and shell you use, this can be e.g. ~/.bashrc, ~/.bash_profile or ~/.zshrc

alias kernel2='source ~/py2_kernel/bin/activate'
alias kernel3='source ~/py3_kernel/bin/activate'

After restarting your shell, you can now install new packages after activating the environment you want to use.

kernel2
python -m pip install <pkg-name>
deactivate

or

kernel3
python -m pip install <pkg-name>
deactivate

Splitting a C++ std::string using tokens, e.g. ";"

You could use a string stream and read the elements into the vector.

Here are many different examples...

A copy of one of the examples:

std::vector<std::string> split(const std::string& s, char seperator)
{
   std::vector<std::string> output;

    std::string::size_type prev_pos = 0, pos = 0;

    while((pos = s.find(seperator, pos)) != std::string::npos)
    {
        std::string substring( s.substr(prev_pos, pos-prev_pos) );

        output.push_back(substring);

        prev_pos = ++pos;
    }

    output.push_back(s.substr(prev_pos, pos-prev_pos)); // Last word

    return output;
}

Multiple FROMs - what it means

The first answer is too complex, historic, and uninformative for my tastes.


It's actually rather simple. Docker provides for a functionality called multi-stage builds the basic idea here is to,

  • Free you from having to manually remove what you don't want, by forcing you to whitelist what you do want,
  • Free resources that would otherwise be taken up because of Docker's implementation.

Let's start with the first. Very often with something like Debian you'll see.

RUN apt-get update \ 
  && apt-get dist-upgrade \
  && apt-get install <whatever> \
  && apt-get clean

We can explain all of this in terms of the above. The above command is chained together so it represents a single change with no intermediate Images required. If it was written like this,

RUN apt-get update ;
RUN apt-get dist-upgrade;
RUN apt-get install <whatever>;
RUN apt-get clean;

It would result in 3 more temporary intermediate Images. Having it reduced to one image, there is one remaining problem: apt-get clean doesn't clean up artifacts used in the install. If a Debian maintainer includes in his install a script that modifies the system that modification will also be present in the final solution (see something like pepperflashplugin-nonfree for an example of that).

By using a multi-stage build you get all the benefits of a single changed action, but it will require you to manually whitelist and copy over files that were introduced in the temporary image using the COPY --from syntax documented here. Moreover, it's a great solution where there is no alternative (like an apt-get clean), and you would otherwise have lots of un-needed files in your final image.

See also

How to delete row in gridview using rowdeleting event?

protected void GridView1_RowDeleting(object sender, GridViewDeleteEventArgs e)
{
    MySqlCommand cmd;
    string id1 = GridView1.DataKeys[e.RowIndex].Value.ToString();
    con.Open();
    cmd = new MySqlCommand("delete from tableName where refno='" + id1 + "'", con);
    cmd.ExecuteNonQuery();
    con.Close();
    BindView();
}
private void BindView()
{
    GridView1.DataSource = ms.dTable("select * from table_name");
    GridView1.DataBind();
}

How to change RGB color to HSV?

This is the VB.net version which works fine for me ported from the C code in BlaM's post.

There's a C implementation here:

http://www.cs.rit.edu/~ncs/color/t_convert.html

Should be very straightforward to convert to C#, as almost no functions are called - just > calculations.


Public Sub HSVtoRGB(ByRef r As Double, ByRef g As Double, ByRef b As Double, ByVal h As Double, ByVal s As Double, ByVal v As Double)
    Dim i As Integer
    Dim f, p, q, t As Double

    If (s = 0) Then
        ' achromatic (grey)
        r = v
        g = v
        b = v
        Exit Sub
    End If

    h /= 60 'sector 0 to 5
    i = Math.Floor(h)
    f = h - i 'factorial part of h
    p = v * (1 - s)
    q = v * (1 - s * f)
    t = v * (1 - s * (1 - f))

    Select Case (i)
        Case 0
            r = v
            g = t
            b = p
            Exit Select
        Case 1
            r = q
            g = v
            b = p
            Exit Select
        Case 2
            r = p
            g = v
            b = t
            Exit Select
        Case 3
            r = p
            g = q
            b = v
            Exit Select
        Case 4
            r = t
            g = p
            b = v
            Exit Select
        Case Else   'case 5:
            r = v
            g = p
            b = q
            Exit Select
    End Select
End Sub

data.map is not a function

There is an error on $.map() invocation, try this:

    function getData(data) {
        this.productID = data.product_id;
        this.productData = data.product_data;
        this.imageID = data.product_data.image_id;
        this.text = data.product_data.text;
        this.link = data.product_data.link;
        this.imageUrl = data.product_data.image_url;
    }

    $.getJSON("json.json?sdfsdfg").done(function (data) {

        var allPosts = $.map(data,function (item) {

            for (var i = 0; i < item.length; i++) {
                new getData(item[i]);
            };

        });

    }); 

The error in your code was that you made return in your AJAX call, so it executed only one time.

java.lang.RuntimeException: Failure delivering result ResultInfo{who=null, request=1888, result=0, data=null} to activity

Adding this first conditional should work:

protected void onActivityResult(int requestCode, int resultCode, Intent data) { 
    if(resultCode != RESULT_CANCELED){
        if (requestCode == CAMERA_REQUEST) {  
            Bitmap photo = (Bitmap) data.getExtras().get("data"); 
            imageView.setImageBitmap(photo);
        }
    }
}

How to create a Jar file in Netbeans

Please do right click on the project and go to properties. Then go to Build and Packaging. You can see the JAR file location that is produced by defualt setting of netbean in the dist directory.

Convert a string to a double - is this possible?

Use doubleval(). But be very careful about using decimals in financial transactions, and validate that user input very carefully.

How can I output a UTF-8 CSV in PHP that Excel will read properly?

you can convert your CSV String with iconv. for example:

$csvString = "Möckmühl;in Möckmühl ist die Hölle los\n";
file_put_contents('path/newTest.csv',iconv("UTF-8", "ISO-8859-1//TRANSLIT",$csvString) );

iOS download and save image inside app

Since we are on IO5 now, you no longer need to write images to disk neccessarily.
You are now able to set "allow external storage" on an coredata binary attribute. According to apples release notes it means the following:

Small data values like image thumbnails may be efficiently stored in a database, but large photos or other media are best handled directly by the file system. You can now specify that the value of a managed object attribute may be stored as an external record - see setAllowsExternalBinaryDataStorage: When enabled, Core Data heuristically decides on a per-value basis if it should save the data directly in the database or store a URI to a separate file which it manages for you. You cannot query based on the contents of a binary data property if you use this option.

How to increment variable under DOS?

Indeed, set in DOS has no option to allow for arithmetic. You could do a giant lookup table, though:

if %COUNTER%==249 set COUNTER=250
...
if %COUNTER%==3 set COUNTER=4
if %COUNTER%==2 set COUNTER=3
if %COUNTER%==1 set COUNTER=2
if %COUNTER%==0 set COUNTER=1

Should CSS always preceed Javascript?

I think this wont be true for all the cases. Because css will download parallel but js cant. Consider for the same case,

Instead of having single css, take 2 or 3 css files and try it out these ways,

1) css..css..js 2) css..js..css 3) js..css..css

I'm sure css..css..js will give better result than all others.

How to run iPhone emulator WITHOUT starting Xcode?

The easiest way without fiddling with command line:

  1. launch Xcode once.
  2. run ios simulator
  3. drag the ios simulator icon to dock it.

Next time you want to use it, just click on the ios simulator icon in the dock.

Setting the default Java character encoding

I think a better approach than setting the platform's default character set, especially as you seem to have restrictions on affecting the application deployment, let alone the platform, is to call the much safer String.getBytes("charsetName"). That way your application is not dependent on things beyond its control.

I personally feel that String.getBytes() should be deprecated, as it has caused serious problems in a number of cases I have seen, where the developer did not account for the default charset possibly changing.

How to append in a json file in Python?

Assuming you have a test.json file with the following content:

{"67790": {"1": {"kwh": 319.4}}}

Then, the code below will load the json file, update the data inside using dict.update() and dump into the test.json file:

import json

a_dict = {'new_key': 'new_value'}

with open('test.json') as f:
    data = json.load(f)

data.update(a_dict)

with open('test.json', 'w') as f:
    json.dump(data, f)

Then, in test.json, you'll have:

{"new_key": "new_value", "67790": {"1": {"kwh": 319.4}}}

Hope this is what you wanted.

SQL count rows in a table

The index statistics likely need to be current, but this will return the number of rows for all tables that are not MS_SHIPPED.

select o.name, i.rowcnt 
from sys.objects o join sys.sysindexes i 
on o.object_id = i.id
where o.is_ms_shipped = 0
and i.rowcnt > 0
order by o.name

Purpose of __repr__ method?

When we create new types by defining classes, we can take advantage of certain features of Python to make the new classes convenient to use. One of these features is "special methods", also referred to as "magic methods".

Special methods have names that begin and end with two underscores. We define them, but do not usually call them directly by name. Instead, they execute automatically under under specific circumstances.

It is convenient to be able to output the value of an instance of an object by using a print statement. When we do this, we would like the value to be represented in the output in some understandable unambiguous format. The repr special method can be used to arrange for this to happen. If we define this method, it can get called automatically when we print the value of an instance of a class for which we defined this method. It should be mentioned, though, that there is also a str special method, used for a similar, but not identical purpose, that may get precedence, if we have also defined it.

If we have not defined, the repr method for the Point3D class, and have instantiated my_point as an instance of Point3D, and then we do this ...

print my_point ... we may see this as the output ...

Not very nice, eh?

So, we define the repr or str special method, or both, to get better output.

**class Point3D(object):
    def __init__(self,a,b,c):
        self.x = a
        self.y = b
        self.z = c
    def __repr__(self):
        return "Point3D(%d, %d, %d)" % (self.x, self.y, self.z)
    def __str__(self):
        return "(%d, %d, %d)" % (self.x, self.y, self.z)
my_point = Point3D(1, 2, 3)
print my_point # __repr__ gets called automatically
print my_point # __str__ gets called automatically**

Output ...

(1, 2, 3) (1, 2, 3)

How to SELECT the last 10 rows of an SQL table which has no ID field?

That can be done using the limit function, this might not seem new but i have added something.The code should go:

SELECT * FROM table_name LIMIT 100,10;

for the above case assume that you have 110 rows from the table and you want to select the last ten, 100 is the row you want to start to print(if you are to print), and ten shows how many rows you want to pick from the table. For a more precised way you can start by selecting all the rows you want to print out and then you grab the last row id if you have an id column(i recommend you put one) then subtract ten from the last id number and that will be where you want to start, this will make your program to function autonomously and for any number of rows, but if you write the value directly i think you will have to change the code every time data is inserted into your table.I think this helps.Pax et Bonum.

How to avoid 'undefined index' errors?

You can use isset() without losing the concatenation:

//snip
$str = 'something'
 . ( isset($output['alternate_title']) ? $output['alternate_title'] : '' )
 . ( isset($output['access_info']) ? $output['access_info'] : '' )
 . //etc.

You could also write a function to return the string if it is set - this probably isn't very efficient:

function getIfSet(& $var) {
    if (isset($var)) {
        return $var;
    }
    return null;
}

$str = getIfSet($output['alternate_title']) . getIfSet($output['access_info']) //etc

You won't get a notice because the variable is passed by reference.

JAX-RS — How to return JSON and HTTP status code together?

I'm not using JAX-RS, but I've got a similar scenario where I use:

response.setStatus(HttpStatus.INTERNAL_SERVER_ERROR.value());

How to handle the modal closing event in Twitter Bootstrap?

Bootstrap Modal Events:

  1. hide.bs.modal => Occurs when the modal is about to be hidden.
  2. hidden.bs.modal => Occurs when the modal is fully hidden (after CSS transitions have completed).
<script type="text/javascript">
    $("#salesitems_modal").on('hide.bs.modal', function () {
        //actions you want to perform after modal is closed.
    });
</script>

I hope this will Help.

How to change content on hover

This little and simple trick I just learnt may help someone trying to avoid :before or :after pseudo elements altogether (for whatever reason) in changing text on hover. You can add both texts in the HTML, but vary the CSS 'display' property based on hover. Assuming the second text 'Add' has a class named 'add-label'; here is a little modification:

span.add-label{
 display:none;
}
.item:hover span.align{
 display:none;
}
.item:hover span.add-label{
 display:block;
}

Here is a demonstration on codepen: https://codepen.io/ifekt/pen/zBaEVJ

Jenkins Host key verification failed

Jenkins is a service account, it doesn't have a shell by design. It is generally accepted that service accounts. shouldn't be able to log in interactively.

To resolve "Jenkins Host key verification failed", do the following steps. I have used mercurial with jenkins.

1)Execute following commands on terminal

             $ sudo su -s /bin/bash jenkins

provide password

2)Generate public private key using the following command:

              ssh-keygen

you can see output as ::

Generating public/private rsa key pair. 
Enter file in which to save the key (/var/lib/jenkins/.ssh/id_rsa): 
Enter passphrase (empty for no passphrase): 
Enter same passphrase again: 

3)Press Enter --> Do not give any passphrase--> press enter

             Key has been generated

4) go to --> cat /var/lib/jenkins/.ssh/id_rsa.pub

5) Copy key from id_rsa.pub

6)Exit from bash

7) ssh@yourrepository

8) vi .ssh/authorized_keys

9) Paste the key

10) exit

11)Manually login to mercurial server

Note: Pls do manually login otherwise jenkins will again give error "host verification failed"

12)once manually done, Now go to Jenkins and give build

Enjoy!!!

Good Luck