Programs & Examples On #Simulink

Simulink® is an environment developed by The MathWorks for multidomain simulation and Model-Based Design for dynamic and embedded systems.

How to change the style of a DatePicker in android?

To change DatePicker colors (calendar mode) at application level define below properties.

<style name="MyAppTheme" parent="Theme.AppCompat.Light">
    <item name="colorAccent">#ff6d00</item>
    <item name="colorControlActivated">#33691e</item>
    <item name="android:selectableItemBackgroundBorderless">@color/colorPrimaryDark</item>
    <item name="colorControlHighlight">#d50000</item>
</style>

See http://www.zoftino.com/android-datepicker-example for other DatePicker custom styles

zoftino DatePicker examples

load jquery after the page is fully loaded

Include your scripts at the bottom of the page before closing body tag.

More info HERE.

What does PermGen actually stand for?

PermGen stands for Permanent Generation.

Here is a brief blurb on DDJ

Reload the page after ajax success

BrixenDK is right.

.ajaxStop() callback executed when all ajax call completed. This is a best place to put your handler.

$(document).ajaxStop(function(){
    window.location.reload();
});

R: numeric 'envir' arg not of length one in predict()

There are several problems here:

  1. The newdata argument of predict() needs a predictor variable. You should thus pass it values for Coupon, instead of Total, which is the response variable in your model.

  2. The predictor variable needs to be passed in as a named column in a data frame, so that predict() knows what the numbers its been handed represent. (The need for this becomes clear when you consider more complicated models, having more than one predictor variable).

  3. For this to work, your original call should pass df in through the data argument, rather than using it directly in your formula. (This way, the name of the column in newdata will be able to match the name on the RHS of the formula).

With those changes incorporated, this will work:

model <- lm(Total ~ Coupon, data=df)
new <- data.frame(Coupon = df$Coupon)
predict(model, newdata = new, interval="confidence")

Using jq to parse and display multiple fields in a json serially

While both of the above answers work well if key,value are strings, I had a situation to append a string and integer (jq errors using the above expressions)

Requirement: To construct a url out below json

pradeep@seleniumframework>curl http://192.168.99.103:8500/v1/catalog/service/apache-443 | jq .[0]
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100   251  100   251    0     0   155k      0 --:--:-- --:--:-- --:--:--  245k
{
  "Node": "myconsul",
  "Address": "192.168.99.103",
  "ServiceID": "4ce41e90ede4:compassionate_wozniak:443",
  "ServiceName": "apache-443",
  "ServiceTags": [],
  "ServiceAddress": "",
  "ServicePort": 1443,
  "ServiceEnableTagOverride": false,
  "CreateIndex": 45,
  "ModifyIndex": 45
}

Solution:

curl http://192.168.99.103:8500/v1/catalog/service/apache-443 |
jq '.[0] | "http://" + .Address + ":" + "\(.ServicePort)"'

Difference between Date(dateString) and new Date(dateString)

I know this is old but by far the easier solution is to just use

var temp = new Date("2010-08-17T12:09:36");

Set Jackson Timezone for Date deserialization

Just came into this issue and finally realised that LocalDateTime doesn't have any timezone information. If you received a date string with timezone information, you need to use this as the type:

ZonedDateTime

Check this link

Using a .php file to generate a MySQL dump

Please reffer to the following link which contains a scriptlet that will help you: http://davidwalsh.name/backup-mysql-database-php

Note: This script may contain bugs with NULL data types

List of foreign keys and the tables they reference in Oracle DB

Try this:

select * from all_constraints where r_constraint_name in (select constraint_name 
from all_constraints where table_name='YOUR_TABLE_NAME');

Concatenate two JSON objects

var baseArrayOfJsonObjects = [{},{}];
for (var i=0; i<arrayOfJsonObjectsFromAjax.length; i++) {
    baseArrayOfJsonObjects.push(arrayOfJsonObjectsFromAjax[i]);
}

Writing Unicode text to a text file?

Deal exclusively with unicode objects as much as possible by decoding things to unicode objects when you first get them and encoding them as necessary on the way out.

If your string is actually a unicode object, you'll need to convert it to a unicode-encoded string object before writing it to a file:

foo = u'?, ?, ?, ? ?, ?, ?, ?, ?, and ?.'
f = open('test', 'w')
f.write(foo.encode('utf8'))
f.close()

When you read that file again, you'll get a unicode-encoded string that you can decode to a unicode object:

f = file('test', 'r')
print f.read().decode('utf8')

Why is Android Studio reporting "URI is not registered"?

Its a plugins problems.

  1. Restart Your android studio.
  2. It will show a pop window for enable plugins
  3. click on enable plugins and then click on Okay.

then it will automatic restart your studio and works will fine.

hope it will works.

Error in file(file, "rt") : cannot open the connection

Set your working directory one level/folder higher. For example, if it is already set as:

setwd("C:/Users/Z/Desktop/Files/RStudio/Coursera/specdata")

go up one level back and set it as:

setwd("C:/Users/Z/Desktop/Files/RStudio/Coursera")

In other words, do not make "specdata" folder as your working directory.

How can strings be concatenated?

More efficient ways of concatenating strings are:

join():

Very efficent, but a bit hard to read.

>>> Section = 'C_type'  
>>> new_str = ''.join(['Sec_', Section]) # inserting a list of strings 
>>> print new_str 
>>> 'Sec_C_type'

String formatting:

Easy to read and in most cases faster than '+' concatenating

>>> Section = 'C_type'
>>> print 'Sec_%s' % Section
>>> 'Sec_C_type'

How to remove td border with html?

simple solution from my end is to keep another Table with border and insert your table in the outer table.

<table border="1">
<tr>
    <td>
        <table border="0">
            <tr>
                <td>one</td>
                <td>two</td>
            </tr>
            <tr>
                <td>one</td>
                <td>two</td>
            </tr>
        </table>
    </td>
</tr>

</table>

MySQL SELECT WHERE datetime matches day (and not necessarily time)

NEVER EVER use a selector like DATE(datecolumns) = '2012-12-24' - it is a performance killer:

  • it will calculate DATE() for all rows, including those, that don't match
  • it will make it impossible to use an index for the query

It is much faster to use

SELECT * FROM tablename 
WHERE columname BETWEEN '2012-12-25 00:00:00' AND '2012-12-25 23:59:59'

as this will allow index use without calculation.

EDIT

As pointed out by Used_By_Already, in the time since the inital answer in 2012, there have emerged versions of MySQL, where using '23:59:59' as a day end is no longer safe. An updated version should read

SELECT * FROM tablename 
WHERE columname >='2012-12-25 00:00:00'
AND columname <'2012-12-26 00:00:00'

The gist of the answer, i.e. the avoidance of a selector on a calculated expression, of course still stands.

Simple calculations for working with lat/lon and km distance?

Thanks Jim Lewis for his great answer and I would like to illustrate this solution by my function in Swift:

func getRandomLocation(forLocation location: CLLocation, withOffsetKM offset: Double) -> CLLocation {
        let latDistance = (Double(arc4random()) / Double(UInt32.max)) * offset * 2.0 - offset
        let longDistanceMax = sqrt(offset * offset - latDistance * latDistance)
        let longDistance = (Double(arc4random()) / Double(UInt32.max)) * longDistanceMax * 2.0 - longDistanceMax

        let lat: CLLocationDegrees = location.coordinate.latitude + latDistance / 110.574
        let lng: CLLocationDegrees = location.coordinate.longitude + longDistance / (111.320 * cos(lat / .pi / 180))
        return CLLocation(latitude: lat, longitude: lng)
    }

In this function to convert distance I use following formulas:

latDistance / 110.574
longDistance / (111.320 * cos(lat / .pi / 180))

No server in Eclipse; trying to install Tomcat

You can install Tomcat server form Eclipse market place.

Help -> Eclipse Market Place search for 'Tomcat' -> Install Eclipse Tomcat plugin.

enter image description here

After installation restart eclipse.

ValueError: Wrong number of items passed - Meaning and suggestions?

for i in range(100):
try:
  #Your code here
  break
except:
  continue

This one worked for me.

VBA: How to delete filtered rows in Excel?

Use SpecialCells to delete only the rows that are visible after autofiltering:

ActiveSheet.Range("$A$1:$I$" & lines).SpecialCells _
    (xlCellTypeVisible).EntireRow.Delete

If you have a header row in your range that you don't want to delete, add an offset to the range to exclude it:

ActiveSheet.Range("$A$1:$I$" & lines).Offset(1, 0).SpecialCells _
    (xlCellTypeVisible).EntireRow.Delete

Representing null in JSON

Let's evaluate the parsing of each:

http://jsfiddle.net/brandonscript/Y2dGv/

var json1 = '{}';
var json2 = '{"myCount": null}';
var json3 = '{"myCount": 0}';
var json4 = '{"myString": ""}';
var json5 = '{"myString": "null"}';
var json6 = '{"myArray": []}';

console.log(JSON.parse(json1)); // {}
console.log(JSON.parse(json2)); // {myCount: null}
console.log(JSON.parse(json3)); // {myCount: 0}
console.log(JSON.parse(json4)); // {myString: ""}
console.log(JSON.parse(json5)); // {myString: "null"}
console.log(JSON.parse(json6)); // {myArray: []}

The tl;dr here:

The fragment in the json2 variable is the way the JSON spec indicates null should be represented. But as always, it depends on what you're doing -- sometimes the "right" way to do it doesn't always work for your situation. Use your judgement and make an informed decision.


JSON1 {}

This returns an empty object. There is no data there, and it's only going to tell you that whatever key you're looking for (be it myCount or something else) is of type undefined.


JSON2 {"myCount": null}

In this case, myCount is actually defined, albeit its value is null. This is not the same as both "not undefined and not null", and if you were testing for one condition or the other, this might succeed whereas JSON1 would fail.

This is the definitive way to represent null per the JSON spec.


JSON3 {"myCount": 0}

In this case, myCount is 0. That's not the same as null, and it's not the same as false. If your conditional statement evaluates myCount > 0, then this might be worthwhile to have. Moreover, if you're running calculations based on the value here, 0 could be useful. If you're trying to test for null however, this is actually not going to work at all.


JSON4 {"myString": ""}

In this case, you're getting an empty string. Again, as with JSON2, it's defined, but it's empty. You could test for if (obj.myString == "") but you could not test for null or undefined.


JSON5 {"myString": "null"}

This is probably going to get you in trouble, because you're setting the string value to null; in this case, obj.myString == "null" however it is not == null.


JSON6 {"myArray": []}

This will tell you that your array myArray exists, but it's empty. This is useful if you're trying to perform a count or evaluation on myArray. For instance, say you wanted to evaluate the number of photos a user posted - you could do myArray.length and it would return 0: defined, but no photos posted.

Set min-width either by content or 200px (whichever is greater) together with max-width

The problem is that flex: 1 sets flex-basis: 0. Instead, you need

.container .box {
  min-width: 200px;
  max-width: 400px;
  flex-basis: auto; /* default value */
  flex-grow: 1;
}

_x000D_
_x000D_
.container {_x000D_
  display: -webkit-flex;_x000D_
  display: flex;_x000D_
  -webkit-flex-wrap: wrap;_x000D_
  flex-wrap: wrap;_x000D_
}_x000D_
_x000D_
.container .box {_x000D_
  -webkit-flex-grow: 1;_x000D_
  flex-grow: 1;_x000D_
  min-width: 100px;_x000D_
  max-width: 400px;_x000D_
  height: 200px;_x000D_
  background-color: #fafa00;_x000D_
  overflow: hidden;_x000D_
}
_x000D_
<div class="container">_x000D_
  <div class="box">_x000D_
    <table>_x000D_
      <tr>_x000D_
        <td>Content</td>_x000D_
        <td>Content</td>_x000D_
        <td>Content</td>_x000D_
      </tr>_x000D_
    </table>    _x000D_
  </div>_x000D_
  <div class="box">_x000D_
    <table>_x000D_
      <tr>_x000D_
        <td>Content</td>_x000D_
      </tr>_x000D_
    </table>    _x000D_
  </div>_x000D_
  <div class="box">_x000D_
    <table>_x000D_
      <tr>_x000D_
        <td>Content</td>_x000D_
        <td>Content</td>_x000D_
      </tr>_x000D_
    </table>    _x000D_
  </div>_x000D_
</div>
_x000D_
_x000D_
_x000D_

AngularJS routing without the hash '#'

**

It is recommended to use the HTML 5 style (PathLocationStrategy) as location strategy in Angular

** Because

  1. It produces the clean and SEO Friendly URLs that are easier for users to understand and remember.
  2. You can take advantage of the server-side rendering, which will make our application load faster, by rendering the pages in the server first before delivering it the client.

Use Hashlocationstrtegy only if you have to support the older browsers.

Click here to know more

Java Security: Illegal key size or default parameters?

This is a code only solution. No need to download or mess with configuration files.

It's a reflection based solution, tested on java 8

Call this method once, early in your program.

//Imports

import javax.crypto.Cipher;
import java.lang.reflect.Constructor;
import java.lang.reflect.Field;
import java.lang.reflect.Modifier;
import java.util.Map;

//method

public static void fixKeyLength() {
    String errorString = "Failed manually overriding key-length permissions.";
    int newMaxKeyLength;
    try {
        if ((newMaxKeyLength = Cipher.getMaxAllowedKeyLength("AES")) < 256) {
            Class c = Class.forName("javax.crypto.CryptoAllPermissionCollection");
            Constructor con = c.getDeclaredConstructor();
            con.setAccessible(true);
            Object allPermissionCollection = con.newInstance();
            Field f = c.getDeclaredField("all_allowed");
            f.setAccessible(true);
            f.setBoolean(allPermissionCollection, true);

            c = Class.forName("javax.crypto.CryptoPermissions");
            con = c.getDeclaredConstructor();
            con.setAccessible(true);
            Object allPermissions = con.newInstance();
            f = c.getDeclaredField("perms");
            f.setAccessible(true);
            ((Map) f.get(allPermissions)).put("*", allPermissionCollection);

            c = Class.forName("javax.crypto.JceSecurityManager");
            f = c.getDeclaredField("defaultPolicy");
            f.setAccessible(true);
            Field mf = Field.class.getDeclaredField("modifiers");
            mf.setAccessible(true);
            mf.setInt(f, f.getModifiers() & ~Modifier.FINAL);
            f.set(null, allPermissions);

            newMaxKeyLength = Cipher.getMaxAllowedKeyLength("AES");
        }
    } catch (Exception e) {
        throw new RuntimeException(errorString, e);
    }
    if (newMaxKeyLength < 256)
        throw new RuntimeException(errorString); // hack failed
}

Credits: Delthas

Why is 1/1/1970 the "epoch time"?

History.

The earliest versions of Unix time had a 32-bit integer incrementing at a rate of 60 Hz, which was the rate of the system clock on the hardware of the early Unix systems. The value 60 Hz still appears in some software interfaces as a result. The epoch also differed from the current value. The first edition Unix Programmer's Manual dated November 3, 1971 defines the Unix time as "the time since 00:00:00, Jan. 1, 1971, measured in sixtieths of a second".

Destroy or remove a view in Backbone.js

You could use the way to solve the problem!

initialize:function(){
    this.trigger('remove-compnents-cart');
    var _this = this;
    Backbone.View.prototype.on('remove-compnents-cart',function(){
        //Backbone.View.prototype.remove;
        Backbone.View.prototype.off();
        _this.undelegateEvents();
    })
}

Another way:Create a global variable,like this:_global.routerList

initialize:function(){
    this.routerName = 'home';
    _global.routerList.push(this);
}
/*remove it in memory*/
for (var i=0;i<_global.routerList.length;i++){
    Backbone.View.prototype.remove.call(_global.routerList[i]);
}

Rename all files in directory from $filename_h to $filename_half?

I had a similar question: In the manual, it describes rename as

rename [option] expression replacement file

so you can use it in this way

rename _h _half *.png

In the code: '_h' is the expression that you are looking for. '_half' is the pattern that you want to replace with. '*.png' is the range of files that you are looking for your possible target files.

Hope this can help c:

How to force Laravel Project to use HTTPS for all routes?

Place this in the AppServiceProvider in the boot() method

if($this->app->environment('production')) {
    \URL::forceScheme('https');
}

Getting NetworkCredential for current user (C#)

If the web service being invoked uses windows integrated security, creating a NetworkCredential from the current WindowsIdentity should be sufficient to allow the web service to use the current users windows login. However, if the web service uses a different security model, there isn't any way to extract a users password from the current identity ... that in and of itself would be insecure, allowing you, the developer, to steal your users passwords. You will likely need to provide some way for your user to provide their password, and keep it in some secure cache if you don't want them to have to repeatedly provide it.

Edit: To get the credentials for the current identity, use the following:

Uri uri = new Uri("http://tempuri.org/");
ICredentials credentials = CredentialCache.DefaultCredentials;
NetworkCredential credential = credentials.GetCredential(uri, "Basic");

How to copy commits from one branch to another?

Suppose I have committed changes to master branch.I will get the commit id(xyz) of the commit now i have to go to branch for which i need to push my commits.

Single commit id xyx

git checkout branch-name
git cherry-pick xyz
git push origin branch-name

Multiple commit id's xyz abc qwe

git checkout branch-name
git cherry-pick xyz abc qwe
git push origin branch-name

How to write a std::string to a UTF-8 text file

std::wstring text = L"??????";
QString qstr = QString::fromStdWString(text);
QByteArray byteArray(qstr.toUtf8());    
std::string str_std( byteArray.constData(), byteArray.length());

jQuery callback for multiple ajax calls

$.ajax({type:'POST', url:'www.naver.com', dataType:'text', async:false,
    complete:function(xhr, textStatus){},
    error:function(xhr, textStatus){},
    success:function( data ){
        $.ajax({type:'POST', 
            ....
            ....
            success:function(data){
                $.ajax({type:'POST',
                    ....
                    ....
            }
        }
    });

I'm sorry but I can't explain what I worte cuz I'm a Korean who can't speak even a word in english. but I think you can easily understand it.

A non-blocking read on a subprocess.PIPE in Python

Try the asyncproc module. For example:

import os
from asyncproc import Process
myProc = Process("myprogram.app")

while True:
    # check to see if process has ended
    poll = myProc.wait(os.WNOHANG)
    if poll != None:
        break
    # print any new output
    out = myProc.read()
    if out != "":
        print out

The module takes care of all the threading as suggested by S.Lott.

SQL Update Multiple Fields FROM via a SELECT Statement

I just had to solve a similar problem where I added a Sequence number (so that items as grouped by a parent ID, have a Sequence that I can order by (and presumably the user can change the sequence number to change the ordering).

In my case, it's insurance for a Patient, and the user gets to set the order they are assigned, so just going by the primary key isn't useful for long-term, but is useful for setting a default.

The problem with all the other solutions is that certain aggregate functions aren't allowed outside of a SELECT

This SELECT gets you the new Sequence number:

select PatientID,
       PatientInsuranceID, 
       Sequence, 
       Row_Number() over(partition by PatientID order by PatientInsuranceID) as RowNum
from PatientInsurance
order by PatientID, PatientInsuranceID

This update command, would be simple, but isn't allowed:

update PatientInsurance
set Sequence = Row_Number() over(partition by PatientID order by PatientInsuranceID)

The solution that worked (I just did it), and is similar to eKek0's solution:

UPDATE PatientInsurance
SET  PatientInsurance.Sequence = q.RowNum
FROM (select PatientInsuranceID, 
             Row_Number() over(partition by PatientID order by PatientInsuranceID) as RowNum
      from PatientInsurance
     ) as q 
WHERE PatientInsurance.PatientInsuranceID=q.PatientInsuranceID 

this lets me select the ID I need to match things up to, and the value I need to set for that ID. Other solutions would have been fine IF I wasn't using Row_Number() which won't work outside of a SELECT.

Given that this is a 1 time operation, it's coding is still simple, and run-speed is fast enough for 4000+ rows

Limiting the number of characters in a string, and chopping off the rest

For readability, I prefer this:

if (inputString.length() > maxLength) {
    inputString = inputString.substring(0, maxLength);
}

over the accepted answer.

int maxLength = (inputString.length() < MAX_CHAR)?inputString.length():MAX_CHAR;
inputString = inputString.substring(0, maxLength);

How to create relationships in MySQL

as ehogue said, put this in your CREATE TABLE

FOREIGN KEY (customer_id) REFERENCES customers(customer_id) 

alternatively, if you already have the table created, use an ALTER TABLE command:

ALTER TABLE `accounts`
  ADD CONSTRAINT `FK_myKey` FOREIGN KEY (`customer_id`) REFERENCES `customers` (`customer_id`) ON DELETE CASCADE ON UPDATE CASCADE;

One good way to start learning these commands is using the MySQL GUI Tools, which give you a more "visual" interface for working with your database. The real benefit to that (over Access's method), is that after designing your table via the GUI, it shows you the SQL it's going to run, and hence you can learn from that.

Convert integer to hexadecimal and back again

string HexFromID(int ID)
{
    return ID.ToString("X");
}

int IDFromHex(string HexID)
{
    return int.Parse(HexID, System.Globalization.NumberStyles.HexNumber);
}

I really question the value of this, though. You're stated goal is to make the value shorter, which it will, but that isn't a goal in itself. You really mean either make it easier to remember or easier to type.

If you mean easier to remember, then you're taking a step backwards. We know it's still the same size, just encoded differently. But your users won't know that the letters are restricted to 'A-F', and so the ID will occupy the same conceptual space for them as if the letter 'A-Z' were allowed. So instead of being like memorizing a telephone number, it's more like memorizing a GUID (of equivalent length).

If you mean typing, instead of being able to use the keypad the user now must use the main part of the keyboard. It's likely to be more difficult to type, because it won't be a word their fingers recognize.

A much better option is to actually let them pick a real username.

What is the best way to conditionally apply a class?

partial

  <div class="col-md-4 text-right">
      <a ng-class="campaign_range === 'thismonth' ? 'btn btn-blue' :  'btn btn-link'" href="#" ng-click='change_range("thismonth")'>This Month</a>
      <a ng-class="campaign_range === 'all' ? 'btn btn-blue' :  'btn btn-link'" href="#" ng-click='change_range("all")'>All Time</a>
  </div>

controller

  $scope.campaign_range = "all";
  $scope.change_range = function(range) { 
        if (range === "all")
        {
            $scope.campaign_range = "all"
        }
        else
        {  
            $scope.campaign_range = "thismonth"
        }
  };

Laravel where on relationship object

@Cermbo's answer is not related to this question. In their answer, Laravel will give you all Events if each Event has 'participants' with IdUser of 1.

But if you want to get all Events with all 'participants' provided that all 'participants' have a IdUser of 1, then you should do something like this :

Event::with(["participants" => function($q){
    $q->where('participants.IdUser', '=', 1);
}])

N.B:

in where use your table name, not Model name.

Write a file on iOS

Swift

func saveFile() {
    let paths = NSSearchPathForDirectoriesInDomains(.DocumentDirectory, .UserDomainMask, true)
    let documentsDirectory = paths[0] as! String
    let fileName = "\(documentsDirectory)/textFile.txt"
    let content = "Hello World"
    content.writeToFile(fileName, atomically: false, encoding: NSUTF8StringEncoding, error: nil)
}

func loadFile() {
    let paths = NSSearchPathForDirectoriesInDomains(.DocumentDirectory, .UserDomainMask, true)
    let documentsDirectory = paths[0] as! String
    let fileName = "\(documentsDirectory)/textFile.txt"
    let content: String = String(contentsOfFile: fileName, encoding: NSUTF8StringEncoding, error: nil)!
    println(content)
}

Swift 2

func saveFile() {
    let paths = NSSearchPathForDirectoriesInDomains(.DocumentDirectory, .UserDomainMask, true)
    let documentsDirectory = paths[0]
    let fileName = "\(documentsDirectory)/textFile.txt"
    let content = "Hello World"
    do{
        try content.writeToFile(fileName, atomically: false, encoding: NSUTF8StringEncoding)
    }catch _ {

    }

}

func loadFile()->String {
    let paths = NSSearchPathForDirectoriesInDomains(.DocumentDirectory, .UserDomainMask, true)
    let documentsDirectory = paths[0] 
    let fileName = "\(documentsDirectory)/textFile.txt"
    let content: String
    do{
       content = try String(contentsOfFile: fileName, encoding: NSUTF8StringEncoding)
    }catch _{
        content=""
    }
    return content;
}

Swift 3

func saveFile() {
    let paths = NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true)
    let documentsDirectory = paths[0]
    let fileName = "\(documentsDirectory)/textFile.txt"
    let content = "Hello World"
    do{
        try content.write(toFile: fileName, atomically: false, encoding: String.Encoding.utf8)
    }catch _ {

    }

}

func loadFile()->String {
    let paths = NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true)
    let documentsDirectory = paths[0]
    let fileName = "\(documentsDirectory)/textFile.txt"
    let content: String
    do{
        content = try String(contentsOfFile: fileName, encoding: String.Encoding.utf8)
    } catch _{
        content=""
    }
    return content;
}

How to change legend title in ggplot

There's another very simple answer which can work for some simple graphs.

Just add a call to guide_legend() into your graph.

ggplot(...) + ... + guide_legend(title="my awesome title")

As shown in the very nice ggplot docs.

If that doesn't work, you can more precisely set your guide parameters with a call to guides:

ggplot(...) + ... + guides(fill=guide_legend("my awesome title"))

You can also vary the shape/color/size by specifying these parameters for your call to guides as well.

FTP/SFTP access to an Amazon S3 Bucket

Answer from 2014 for the people who are down-voting me:

Well, S3 isn't FTP. There are lots and lots of clients that support S3, however.

Pretty much every notable FTP client on OS X has support, including Transmit and Cyberduck.

If you're on Windows, take a look at Cyberduck or CloudBerry.

Updated answer for 2019:

AWS has recently released the AWS Transfer for SFTP service, which may do what you're looking for.

Printing all variables value from a class

From Implementing toString:

public String toString() {
  StringBuilder result = new StringBuilder();
  String newLine = System.getProperty("line.separator");

  result.append( this.getClass().getName() );
  result.append( " Object {" );
  result.append(newLine);

  //determine fields declared in this class only (no fields of superclass)
  Field[] fields = this.getClass().getDeclaredFields();

  //print field names paired with their values
  for ( Field field : fields  ) {
    result.append("  ");
    try {
      result.append( field.getName() );
      result.append(": ");
      //requires access to private field:
      result.append( field.get(this) );
    } catch ( IllegalAccessException ex ) {
      System.out.println(ex);
    }
    result.append(newLine);
  }
  result.append("}");

  return result.toString();
}

Full-screen iframe with a height of 100%

Only this worked for me (but for "same-domain"):

function MakeIframeFullHeight(iframeElement){
    iframeElement.style.width   = "100%";
    var ifrD = iframeElement.contentDocument || iframeElement.contentWindow.document;
    var mHeight = parseInt( window.getComputedStyle( ifrD.documentElement).height );  // Math.max( ifrD.body.scrollHeight, .. offsetHeight, ....clientHeight,
    var margins = ifrD.body.style.margin + ifrD.body.style.padding + ifrD.documentElement.style.margin + ifrD.documentElement.style.padding;
    if(margins=="") { margins=0;  ifrD.body.style.margin="0px"; }
    (function(){
       var interval = setInterval(function(){
        if(ifrD.readyState  == 'complete' ){
            iframeElement.style.height  = (parseInt(window.getComputedStyle( ifrD.documentElement).height) + margins+1) +"px";
            setTimeout( function(){ clearInterval(interval); }, 1000 );
        } 
       },1000)
    })();
}

you can use either:

MakeIframeFullHeight(document.getElementById("iframe_id"));

or

<iframe .... onload="MakeIframeFullHeight(this);" ....

Creating threads - Task.Factory.StartNew vs new Thread()

Your first block of code tells CLR to create a Thread (say. T) for you which is can be run as background (use thread pool threads when scheduling T ). In concise, you explicitly ask CLR to create a thread for you to do something and call Start() method on thread to start.

Your second block of code does the same but delegate (implicitly handover) the responsibility of creating thread (background- which again run in thread pool) and the starting thread through StartNew method in the Task Factory implementation.

This is a quick difference between given code blocks. Having said that, there are few detailed difference which you can google or see other answers from my fellow contributors.

Create a directory if it doesn't exist

OpenCV Specific

Opencv supports filesystem, probably through its dependency Boost.

#include <opencv2/core/utils/filesystem.hpp>
cv::utils::fs::createDirectory(outputDir);

How to tell git to use the correct identity (name and email) for a given project?

git config user.email "[email protected]"

Doing that one inside a repo will set the configuration on THAT repo, and not globally.

Seems like that's pretty much what you're after, unless I'm misreading you.

Relationship between hashCode and equals method in Java

A contract is: If two objects are equal then they should have the same hashcode and if two objects are not equal then they may or may not have same hash code.

Try using your object as key in HashMap (edited after comment from joachim-sauer), and you will start facing trouble. A contract is a guideline, not something forced upon you.

How to remove all CSS classes using jQuery/JavaScript?

You can just try

$(document).ready(function() {
   $('body').find('#item').removeClass();
});

If you have to access to that element without class name, for example you have to add a new class name, you can do that:

$(document).ready(function() {
   $('body').find('#item').removeClass().addClass('class-name');
});

I use that function in my projet to remove and add class in a html builder. Good luck.

What does Visual Studio mean by normalize inconsistent line endings?

The Wikipedia newline article might help you out. Here is an excerpt:

The different newline conventions often cause text files that have been transferred between systems of different types to be displayed incorrectly. For example, files originating on Unix or Apple Macintosh systems may appear as a single long line on some programs running on Microsoft Windows. Conversely, when viewing a file originating from a Windows computer on a Unix system, the extra CR may be displayed as ^M or at the end of each line or as a second line break.

When should you use a class vs a struct in C++?

I never use "struct" in C++.

I can't ever imagine a scenario where you would use a struct when you want private members, unless you're willfully trying to be confusing.

It seems that using structs is more of a syntactic indication of how the data will be used, but I'd rather just make a class and try to make that explicit in the name of the class, or through comments.

E.g.

class PublicInputData {
    //data members
 };

How to do "If Clicked Else .."

This is all you need: http://api.jquery.com/click/

Having an "else" doesn't apply in this scenario, else would mean "did not click", in which case you just wouldn't do anything.

Downloading a large file using curl

<?php
set_time_limit(0);
//This is the file where we save the    information
$fp = fopen (dirname(__FILE__) . '/localfile.tmp', 'w+');
//Here is the file we are downloading, replace spaces with %20
$ch = curl_init(str_replace(" ","%20",$url));
curl_setopt($ch, CURLOPT_TIMEOUT, 50);
// write curl response to file
curl_setopt($ch, CURLOPT_FILE, $fp); 
curl_setopt($ch, CURLOPT_FOLLOWLOCATION, true);
// get curl response
curl_exec($ch); 
curl_close($ch);
fclose($fp);
?>

Converting HTML files to PDF

If you have the funding, nothing beats Prince XML as this video shows

Java: Get month Integer from Date

If you can't use Joda time and you still live in the dark world :) ( Java 5 or lower ) you can enjoy this :

Note: Make sure your date is allready made by the format : dd/MM/YYYY

/**
Make an int Month from a date
*/
public static int getMonthInt(Date date) {

    SimpleDateFormat dateFormat = new SimpleDateFormat("MM");
    return Integer.parseInt(dateFormat.format(date));
}

/**
Make an int Year from a date
*/
public static int getYearInt(Date date) {

    SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy");
    return Integer.parseInt(dateFormat.format(date));
}

How to install XCODE in windows 7 platform?

X-code is primarily made for OS-X or iPhone development on Mac systems. Versions for Windows are not available. However this might help!

There is no way to get Xcode on Windows; however you can use a different SDK like Corona instead although it will not use Objective-C (I believe it uses Lua). I have however heard that it is horrible to use.

Source: classroomm.com

Dart/Flutter : Converting timestamp

If you are using firestore (and not just storing the timestamp as a string) a date field in a document will return a Timestamp. The Timestamp object contains a toDate() method.

Using timeago you can create a relative time quite simply:

_ago(Timestamp t) {
  return timeago.format(t.toDate(), 'en_short');
}

build() {
  return  Text(_ago(document['mytimestamp'])));
}

Make sure to set _firestore.settings(timestampsInSnapshotsEnabled: true); to return a Timestamp instead of a Date object.

How to delete a workspace in Perforce (using p4v)?

In P4V click View > Workspaces

If the workspace to be deleted is not visible in the list you may have to uncheck the box Show only workspaces available for use on this computer

Right-click the workspace to be deleted and choose Edit Workspace 'My_workspace'

On the Advanced tab uncheck the box Locked: only the owner can edit workspace settings > then click OK

Now back on the Workspaces tab of Perforce right-click the workspace to be deleted and choose Delete Workspace 'My_workspace'

P4V should remove the item from the drop-down list when clicking on it.

There is a case where a previously deleted workspace remains in the drop-down list, and P4V displays the following error:

P4V Workspace Switch Error. This workspace cannot be used on this computer either because the host field does not match your computer name or the workspace root cannot be used on this computer.

If this error occurs, the workspace(possibly on another host) may have only been unloaded. Click the P4V Workspaces Recycle bin

P4V Recycle

In the resulting Unloaded Workspaces window right-click the offending workspace and choose Delete Workspace 'My_workspace'. P4V should now remove the workspace item from the drop-down list.

Appending to list in Python dictionary

dates_dict[key] = dates_dict.get(key, []).append(date) sets dates_dict[key] to None as list.append returns None.

In [5]: l = [1,2,3]

In [6]: var = l.append(3)

In [7]: print var
None

You should use collections.defaultdict

import collections
dates_dict = collections.defaultdict(list)

How to make child process die after parent exits?

Install a trap handler to catch SIGINT, which kills off your child process if it's still alive, though other posters are correct that it won't catch SIGKILL.

Open a .lockfile with exclusive access and have the child poll on it trying to open it - if the open succeeds, the child process should exit

Reset the Value of a Select Box

I found a little utility function a while back and I've been using it for resetting my form elements ever since (source: http://www.learningjquery.com/2007/08/clearing-form-data):

function clearForm(form) {
  // iterate over all of the inputs for the given form element
  $(':input', form).each(function() {
    var type = this.type;
    var tag = this.tagName.toLowerCase(); // normalize case
    // it's ok to reset the value attr of text inputs, 
    // password inputs, and textareas
    if (type == 'text' || type == 'password' || tag == 'textarea')
      this.value = "";
    // checkboxes and radios need to have their checked state cleared 
    // but should *not* have their 'value' changed
    else if (type == 'checkbox' || type == 'radio')
      this.checked = false;
    // select elements need to have their 'selectedIndex' property set to -1
    // (this works for both single and multiple select elements)
    else if (tag == 'select')
      this.selectedIndex = -1;
  });
};

... or as a jQuery plugin...

$.fn.clearForm = function() {
  return this.each(function() {
    var type = this.type, tag = this.tagName.toLowerCase();
    if (tag == 'form')
      return $(':input',this).clearForm();
    if (type == 'text' || type == 'password' || tag == 'textarea')
      this.value = '';
    else if (type == 'checkbox' || type == 'radio')
      this.checked = false;
    else if (tag == 'select')
      this.selectedIndex = -1;
  });
};

Contains method for a slice

func Contain(target interface{}, list interface{}) (bool, int) {
    if reflect.TypeOf(list).Kind() == reflect.Slice || reflect.TypeOf(list).Kind() == reflect.Array {
        listvalue := reflect.ValueOf(list)
        for i := 0; i < listvalue.Len(); i++ {
            if target == listvalue.Index(i).Interface() {
                return true, i
            }
        }
    }
    if reflect.TypeOf(target).Kind() == reflect.String && reflect.TypeOf(list).Kind() == reflect.String {
        return strings.Contains(list.(string), target.(string)), strings.Index(list.(string), target.(string))
    }
    return false, -1
}

Convert javascript array to string

I needed an array to became a String rappresentation of an array I mean I needed that

var a = ['a','b','c'];
//became a "real" array string-like to pass on query params so was easy to do:
JSON.stringify(a); //-->"['a','b','c']"

maybe someone need it :)

Excel VBA - Sum up a column

Here is what you can do if you want to add a column of numbers in Excel. ( I am using Excel 2010 but should not make a difference.)

Example: Lets say you want to add the cells in Column B form B10 to B100 & want the answer to be in cell X or be Variable X ( X can be any cell or any variable you create such as Dim X as integer, etc). Here is the code:

Range("B5") = "=SUM(B10:B100)"

or

X = "=SUM(B10:B100)

There are no quotation marks inside the parentheses in "=Sum(B10:B100) but there are quotation marks inside the parentheses in Range("B5"). Also there is a space between the equals sign and the quotation to the right of it.

It will not matter if some cells are empty, it will simply see them as containing zeros!

This should do it for you!

Round to 2 decimal places

Don't use doubles. You can lose some precision. Here's a general purpose function.

public static double round(double unrounded, int precision, int roundingMode)
{
    BigDecimal bd = new BigDecimal(unrounded);
    BigDecimal rounded = bd.setScale(precision, roundingMode);
    return rounded.doubleValue();
}

You can call it with

round(yourNumber, 3, BigDecimal.ROUND_HALF_UP);

"precision" being the number of decimal points you desire.

How to run cron once, daily at 10pm

The syntax for crontab

* * * * * 

Minute(0-59) Hour(0-24) Day_of_month(1-31) Month(1-12) Day_of_week(0-6) Command_to_execute

Your syntax

* 22 * * * test > /dev/null

your job will Execute every minute at 22:00 hrs all week, month and year.

adding an option (0-59) at the minute place will run it once at 22:00 hrs all week, month and year.

0 22 * * * command_to_execute 

Source https://www.adminschoice.com/crontab-quick-reference

What does it mean when an HTTP request returns status code 0?

As detailed by this answer on this page, a status code of 0 means the request failed for some reason, and a javascript library interpreted the fail as a status code of 0.

To test this you can do either of the following:

1) Use this chrome extension, Requestly to redirect your url from the https version of your url to the http version, as this will cause a mixed content security error, and ultimately generate a status code of 0. The advantage of this approach is that you don't have to change your app at all, and you can simply "rewrite" your url using this extension.

2) Change the code of your app to optionally make your endpoint redirect to the http version of your url instead of the https version (or vice versa). If you do this, the request will fail with status code 0.

What is the format for the PostgreSQL connection string / URL?

The following worked for me

const conString = "postgres://YourUserName:YourPassword@YourHostname:5432/YourDatabaseName";

What are the recommendations for html <base> tag?

The hash "#" currently works for jump links in conjunction with the base element, but only in the latest versions of Google Chrome and Firefox, NOT IE9.

IE9 appears to cause the page to be reloaded, without jumping anywhere. If you are using jump links on the outside of an iframe, while directing the frame to load the jump links on a separate page within the frame, you will instead get a second copy of the jump link page loaded inside the frame.

git status shows fatal: bad object HEAD

In my case the error came out of nowhere, but didn't let me push to the remote branch.

git fetch origin

And that solved it.

I agree this may not solve the issue for everyone, but before trying a more complex approach give it a shot at this one, nothing to loose.

How to check whether a select box is empty using JQuery/Javascript

To check whether select box has any values:

if( $('#fruit_name').has('option').length > 0 ) {

To check whether selected value is empty:

if( !$('#fruit_name').val() ) { 

What is the best way to prevent session hijacking?

To reduce the risk you can also associate the originating IP with the session. That way an attacker has to be within the same private network to be able to use the session.

Checking referer headers can also be an option but those are more easily spoofed.

Call PowerShell script PS1 from another PS1 script inside Powershell ISE

One line solution:

& ((Split-Path $MyInvocation.InvocationName) + "\MyScript1.ps1")

When and where to use GetType() or typeof()?

You may find it easier to use the is keyword:

if (mycontrol is TextBox)

What is a "callback" in C and how are they implemented?

It is lot easier to understand an idea through example. What have been told about callback function in C so far are great answers, but probably the biggest benefit of using the feature is to keep the code clean and uncluttered.

Example

The following C code implements quick sorting. The most interesting line in the code below is this one, where we can see the callback function in action:

qsort(arr,N,sizeof(int),compare_s2b);

The compare_s2b is the name of function which qsort() is using to call the function. This keeps qsort() so uncluttered (hence easier to maintain). You just call a function by name from inside another function (of course, the function prototype declaration, at the least, must precde before it can be called from another function).

The Complete Code

#include <stdio.h>
#include <stdlib.h>

int arr[]={56,90,45,1234,12,3,7,18};
//function prototype declaration 

int compare_s2b(const void *a,const void *b);

int compare_b2s(const void *a,const void *b);

//arranges the array number from the smallest to the biggest
int compare_s2b(const void* a, const void* b)
{
    const int* p=(const int*)a;
    const int* q=(const int*)b;

    return *p-*q;
}

//arranges the array number from the biggest to the smallest
int compare_b2s(const void* a, const void* b)
{
    const int* p=(const int*)a;
    const int* q=(const int*)b;

    return *q-*p;
}

int main()
{
    printf("Before sorting\n\n");

    int N=sizeof(arr)/sizeof(int);

    for(int i=0;i<N;i++)
    {
        printf("%d\t",arr[i]);
    }

    printf("\n");

    qsort(arr,N,sizeof(int),compare_s2b);

    printf("\nSorted small to big\n\n");

    for(int j=0;j<N;j++)
    {
        printf("%d\t",arr[j]);
    }

    qsort(arr,N,sizeof(int),compare_b2s);

    printf("\nSorted big to small\n\n");

    for(int j=0;j<N;j++)
    {
        printf("%d\t",arr[j]);
    }

    exit(0);
}

Where can I get a list of Countries, States and Cities?

Geonames has a lot of data on places (including towns and cities) but it seems to be contributed and perhaps not complete.

Perhaps also try SQL Dumpster, I've used this website a lot for these kinds of databases, cities, provinces, etc. Unfortunately it's not free but only appears to be a one-time fee.

Check if a variable is null in plsql

In PL/SQL you can't use operators such as '=' or '<>' to test for NULL because all comparisons to NULL return NULL. To compare something against NULL you need to use the special operators IS NULL or IS NOT NULL which are there for precisely this purpose. Thus, instead of writing

IF var = NULL THEN...

you should write

IF VAR IS NULL THEN...

In the case you've given you also have the option of using the NVL built-in function. NVL takes two arguments, the first being a variable and the second being a value (constant or computed). NVL looks at its first argument and, if it finds that the first argument is NULL, returns the second argument. If the first argument to NVL is not NULL, the first argument is returned. So you could rewrite

IF var IS NULL THEN
  var := 5;
END IF;

as

var := NVL(var, 5);

I hope this helps.

EDIT

And because it's nearly ten years since I wrote this answer, let's celebrate by expanding it just a bit.

The COALESCE function is the ANSI equivalent of Oracle's NVL. It differs from NVL in a couple of IMO good ways:

  1. It takes any number of arguments, and returns the first one which is not NULL. If all the arguments passed to COALESCE are NULL, it returns NULL.

  2. In contrast to NVL, COALESCE only evaluates arguments if it must, while NVL evaluates both of its arguments and then determines if the first one is NULL, etc. So COALESCE can be more efficient, because it doesn't spend time evaluating things which won't be used (and which can potentially cause unwanted side effects), but it also means that COALESCE is not a 100% straightforward drop-in replacement for NVL.

How to Compare a long value is equal to Long value

It works as expected,

Try checking IdeOneDemo

 public static void main(String[] args) {
        long a = 1111;
        Long b = 1113l;

        if (a == b) {
            System.out.println("Equals");
        } else {
            System.out.println("not equals");
        }
    }

prints

not equals for me

Use compareTo() to compare Long, == wil not work in all case as far as the value is cached

Make the first character Uppercase in CSS

I would recommend that you use the following code in CSS:

    text-transform:uppercase; 

Make sure you put it in your class.

Header div stays at top, vertical scrolling div below with scrollbar only attached to that div

Here is a demo. Use position:fixed; top:0; left:0; so the header always stay on top.

?#header {
    background:red;
    height:50px;
    width:100%;
    position:fixed;
    top:0;
    left:0;    
}.scroller {
    height:300px; 
    overflow:scroll;    
}

How do I make an editable DIV look like a text field?

I would suggest this for matching Chrome's style, extended from Jarish's example. Notice the cursor property which previous answers have omitted.

cursor: text;
border: 1px solid #ccc;
font: medium -moz-fixed;
font: -webkit-small-control;
height: 200px;
overflow: auto;
padding: 2px;
resize: both;
-moz-box-shadow: inset 0px 1px 2px #ccc;
-webkit-box-shadow: inset 0px 1px 2px #ccc;
box-shadow: inset 0px 1px 2px #ccc;

What is the Angular equivalent to an AngularJS $watch?

This behaviour is now part of the component lifecycle.

A component can implement the ngOnChanges method in the OnChanges interface to get access to input changes.

Example:

import {Component, Input, OnChanges} from 'angular2/core';


@Component({
  selector: 'hero-comp',
  templateUrl: 'app/components/hero-comp/hero-comp.html',
  styleUrls: ['app/components/hero-comp/hero-comp.css'],
  providers: [],
  directives: [],

  pipes: [],
  inputs:['hero', 'real']
})
export class HeroComp implements OnChanges{
  @Input() hero:Hero;
  @Input() real:string;
  constructor() {
  }
  ngOnChanges(changes) {
      console.log(changes);
  }
}

Can you do a partial checkout with Subversion?

Or do a non-recursive checkout of /trunk, then just do a manual update on the 3 directories you need.

react-native: command not found

If who have error , try it with sudo:

sudo npm install -g react-native-cli

switch case statement error: case expressions must be constant expression

It was throwing me this error when I using switch in a function with variables declared in my class:

private void ShowCalendar(final Activity context, Point p, int type) 
{
    switch (type) {
        case type_cat:
            break;

        case type_region:
            break;

        case type_city:
            break;

        default:
            //sth
            break;
    }
}

The problem was solved when I declared final to the variables in the start of the class:

final int type_cat=1, type_region=2, type_city=3;

How to make a simple rounded button in Storyboard?

I found the easiest way to do this, is by setting the cornerRadius to half of the height of the view.

button.layer.cornerRadius = button.bounds.size.height/2

Regular Expression to find a string included between two characters while EXCLUDING the delimiters

Most updated solution

If you are using Javascript, the best solution that I came up with is using match instead of exec method. Then, iterate matches and remove the delimiters with the result of the first group using $1

const text = "This is a test string [more or less], [more] and [less]";
const regex = /\[(.*?)\]/gi;
const resultMatchGroup = text.match(regex); // [ '[more or less]', '[more]', '[less]' ]
const desiredRes = resultMatchGroup.map(match => match.replace(regex, "$1"))
console.log("desiredRes", desiredRes); // [ 'more or less', 'more', 'less' ]

As you can see, this is useful for multiple delimiters in the text as well

View more than one project/solution in Visual Studio

You can have multiple projects in one instance of Visual Studio. The point of a VS solution is to bring together all the projects you want to work with in one place, so you can't have multiple solutions in one instance. You'd have to open each solution separately.

C# event with custom arguments

public enum MyEvents
{
    Event1
}

public class CustomEventArgs : EventArgs
{
    public MyEvents MyEvents { get; set; }
}


private EventHandler<CustomEventArgs> onTrigger;

public event EventHandler<CustomEventArgs> Trigger
{
    add
    {
        onTrigger += value;
    }
    remove
    {
        onTrigger -= value;
    }
}

protected void OnTrigger(CustomEventArgs e)
{
    if (onTrigger != null)
    {
        onTrigger(this, e);
    }
}

Test for existence of nested JavaScript object key

I was looking for the value to be returned if the property exists, so I modified the answer by CMS above. Here's what I came up with:

_x000D_
_x000D_
function getNestedProperty(obj, key) {_x000D_
  // Get property array from key string_x000D_
  var properties = key.split(".");_x000D_
_x000D_
  // Iterate through properties, returning undefined if object is null or property doesn't exist_x000D_
  for (var i = 0; i < properties.length; i++) {_x000D_
    if (!obj || !obj.hasOwnProperty(properties[i])) {_x000D_
      return;_x000D_
    }_x000D_
    obj = obj[properties[i]];_x000D_
  }_x000D_
_x000D_
  // Nested property found, so return the value_x000D_
  return obj;_x000D_
}_x000D_
_x000D_
_x000D_
Usage:_x000D_
_x000D_
getNestedProperty(test, "level1.level2.level3") // "level3"_x000D_
getNestedProperty(test, "level1.level2.foo") // undefined
_x000D_
_x000D_
_x000D_

How to make a HTML list appear horizontally instead of vertically using CSS only?

You will have to use something like below

_x000D_
_x000D_
#menu ul{_x000D_
  list-style: none;_x000D_
}_x000D_
#menu li{_x000D_
  display: inline;_x000D_
}_x000D_
 
_x000D_
<div id="menu">_x000D_
  <ul>_x000D_
    <li>First menu item</li>_x000D_
    <li>Second menu item</li>_x000D_
    <li>Third menu item</li>_x000D_
  </ul>_x000D_
</div>
_x000D_
_x000D_
_x000D_

"unrecognized import path" with go get

I installed Go with brew on OSX 10.11, and found I had to set GOROOT to:

/usr/local/Cellar/go/1.5.1/libexec

(Of course replace the version in this path with go version you have)

Brew uses symlinks, which were fooling the gotool. So follow the links home.

How do I get the last word in each line with bash

there are many ways. as awk solutions shows, it's the clean solution

sed solution is to delete anything till the last space. So if there is no space at the end, it should work

sed 's/.* //g' <file>

you can avoid sed also and go for a while loop.

while read line
do [ -z "$line" ] && continue ;
echo $line|rev|cut -f1 -d' '|rev
done < file

it reads a line, reveres it, cuts the first (i.e. last in the original) and restores back

the same can be done in a pure bash way

while read line
do [ -z "$line" ] && continue ;
echo ${line##* }
done < file

it is called parameter expansion

How do you change Background for a Button MouseOver in WPF?

A slight more difficult answer that uses ControlTemplate and has an animation effect (adapted from https://docs.microsoft.com/en-us/dotnet/framework/wpf/controls/customizing-the-appearance-of-an-existing-control)

In your resource dictionary define a control template for your button like this one:

<ControlTemplate TargetType="Button" x:Key="testButtonTemplate2">
    <Border Name="RootElement">
        <Border.Background>
            <SolidColorBrush x:Name="BorderBrush" Color="Black"/>
        </Border.Background>

        <Grid Margin="4" >
            <Grid.Background>
                <SolidColorBrush x:Name="ButtonBackground" Color="Aquamarine"/>
            </Grid.Background>
            <ContentPresenter HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" VerticalAlignment="{TemplateBinding VerticalContentAlignment}" Margin="4,5,4,4"/>
        </Grid>
        <VisualStateManager.VisualStateGroups>
            <VisualStateGroup x:Name="CommonStates">
                <VisualState x:Name="Normal"/>
                <VisualState x:Name="MouseOver">
                    <Storyboard>
                        <ColorAnimation Storyboard.TargetName="ButtonBackground" Storyboard.TargetProperty="Color" To="Red"/>
                    </Storyboard>
                </VisualState>
                <VisualState x:Name="Pressed">
                    <Storyboard>
                        <ColorAnimation Storyboard.TargetName="ButtonBackground" Storyboard.TargetProperty="Color" To="Red"/>
                    </Storyboard>
                </VisualState>
            </VisualStateGroup>
        </VisualStateManager.VisualStateGroups>
    </Border>
</ControlTemplate>

in your XAML you can use the template above for your button as below:

Define your button

<Button Template="{StaticResource testButtonTemplate2}" 
HorizontalAlignment="Center" VerticalAlignment="Center" 
Foreground="White">My button</Button>

Hope it helps

detect key press in python?

Python has a keyboard module with many features. Install it, perhaps with this command:

pip3 install keyboard

Then use it in code like:

import keyboard  # using module keyboard
while True:  # making a loop
    try:  # used try so that if user pressed other than the given key error will not be shown
        if keyboard.is_pressed('q'):  # if key 'q' is pressed 
            print('You Pressed A Key!')
            break  # finishing the loop
    except:
        break  # if user pressed a key other than the given key the loop will break

Are there inline functions in java?

What you said above is correct. Sometimes final methods are created as inline, but there is no other way to explicitly create an inline function in java.

Laravel Migration Change to Make a Column Nullable

He're the full migration for Laravel 5:

public function up()
{
    Schema::table('users', function (Blueprint $table) {
        $table->unsignedInteger('user_id')->nullable()->change();
    });
}

public function down()
{
    Schema::table('users', function (Blueprint $table) {
        $table->unsignedInteger('user_id')->nullable(false)->change();
    });
}

The point is, you can remove nullable by passing false as an argument.

How to set cornerRadius for only top-left and top-right corner of a UIView?

Try this code,

UIBezierPath *maskPath = [UIBezierPath bezierPathWithRoundedRect:view.bounds byRoundingCorners:( UIRectCornerTopLeft | UIRectCornerTopRight) cornerRadii:CGSizeMake(5.0, 5.0)];

CAShapeLayer *maskLayer = [[CAShapeLayer alloc] init];
maskLayer.frame = self.view.bounds;
maskLayer.path  = maskPath.CGPath;

view.layer.mask = maskLayer;

How can I debug a .BAT script?

or, open a cmd window, then call the batch from there, the output will be on the screen.

How to compare two columns in Excel (from different sheets) and copy values from a corresponding column if the first two columns match?

Vlookup is good if the reference values (column A, sheet 1) are in ascending order. Another option is Index and Match, which can be used no matter the order (As long as the values in column a, sheet 1 are unique)

This is what you would put in column B on sheet 2

=INDEX(Sheet1!A$1:B$6,MATCH(A1,Sheet1!A$1:A$6),2)

Setting Sheet1!A$1:B$6 and Sheet1!A$1:A$6 as named ranges makes it a little more user friendly.

How to flush output of print function?

Using the -u command-line switch works, but it is a little bit clumsy. It would mean that the program would potentially behave incorrectly if the user invoked the script without the -u option. I usually use a custom stdout, like this:

class flushfile:
  def __init__(self, f):
    self.f = f

  def write(self, x):
    self.f.write(x)
    self.f.flush()

import sys
sys.stdout = flushfile(sys.stdout)

... Now all your print calls (which use sys.stdout implicitly), will be automatically flushed.

Iterate through a C++ Vector using a 'for' loop

A correct way of iterating over the vector and printing its values is as follows:

#include<vector>

// declare the vector of type int
vector<int> v;

// insert elements in the vector
for (unsigned int i = 0; i < 5; ++i){
    v.push_back(i);
}

// print those elements
for (auto it = v.begin(); it != v.end(); ++it){
    std::cout << *it << std::endl;
}

But at least in the present case it is nicer to use a range-based for loop:
for (auto x: v) std::cout << x << "\n";
(You may also add & after auto to make x a reference to the elements rather than a copy of them. It is then very similar to the above iterator-based approach, but easier to read and write.)

How can I stop redis-server?

If you are running redis in a docker container, none of the present answers will help. You have to stop redis container. Otherwise, redis process will keep respawning.

$ docker ps
CONTAINER ID        IMAGE                    PORTS                             
e1c008ab04a2        bitnami/redis:4.0.8-r0   0.0.0.0:6379->6379/tcp

$ docker stop e1c008ab04a2
e1c008ab04a2

"Cannot GET /" with Connect on Node.js

var connect = require('connect');
var serveStatic = require('serve-static');
var app = connect(); 
app.use(serveStatic('../angularjs'),  {default: 'angular.min.js'}); app.listen(3000); 

Unable to run Java code with Intellij IDEA

If you are just opened a new java project then create a new folder src/ in the man project location.

Then cut and paste all your package in that folder.

Then Right click on src directory and select option Mark Directory As > Sources Root.

How do I declare class-level properties in Objective-C?

If you have many class level properties then a singleton pattern might be in order. Something like this:

// Foo.h
@interface Foo

+ (Foo *)singleton;

@property 1 ...
@property 2 ...
@property 3 ...

@end

And

// Foo.m

#import "Foo.h"

@implementation Foo

static Foo *_singleton = nil;

+ (Foo *)singleton {
    if (_singleton == nil) _singleton = [[Foo alloc] init];

    return _singleton;
}

@synthesize property1;
@synthesize property2;
@synthesise property3;

@end

Now access your class-level properties like this:

[Foo singleton].property1 = value;
value = [Foo singleton].property2;

curl_exec() always returns false

This happened to me yesterday and in my case was because I was following a PDF manual to develop some module to communicate with an API and while copying the link directly from the manual, for some odd reason, the hyphen from the copied link was in a different encoding and hence the curl_exec() was always returning false because it was unable to communicate with the server.

It took me a couple hours to finally understand the diference in the characters bellow:

https://www.e-example.com/api
https://www.e-example.com/api

Every time I tried to access the link directly from a browser it converted to something likehttps://www.xn--eexample-0m3d.com/api.

It may seem to you that they are equal but if you check the encoding of the hyphens here you'll see that the first hyphen is a unicode characters U+2010 and the other is a U+002D.

Hope this helps someone.

includes() not working in all browsers

One more solution is to use contains which will return true or false

_.contains($(".right-tree").css("background-image"), "stage1")

Hope this helps

AttributeError: 'module' object has no attribute

You have mutual top-level imports, which is almost always a bad idea.

If you really must have mutual imports in Python, the way to do it is to import them within a function:

# In b.py:
def cause_a_to_do_something():
    import a
    a.do_something()

Now a.py can safely do import b without causing problems.

(At first glance it might appear that cause_a_to_do_something() would be hugely inefficient because it does an import every time you call it, but in fact the import work only gets done the first time. The second and subsequent times you import a module, it's a quick operation.)

convert string to specific datetime format?

More formats:

 require 'date'

 date = "01/07/2016 09:17AM"
 DateTime.parse(date).strftime("%A, %b %d")
 #=> Friday, Jul 01

 DateTime.parse(date).strftime("%m/%d/%Y")
 #=> 07/01/2016

 DateTime.parse(date).strftime("%m-%e-%y %H:%M")
 #=> 07- 1-16 09:17

 DateTime.parse(date).strftime("%b %e")
 #=> Jul  1

 DateTime.parse(date).strftime("%l:%M %p")
 #=>  9:17 AM

 DateTime.parse(date).strftime("%B %Y")
 #=> July 2016
 DateTime.parse(date).strftime("%b %d, %Y")
 #=> Jul 01, 2016
 DateTime.parse(date).strftime("%a, %e %b %Y %H:%M:%S %z")
 #=> Fri,  1 Jul 2016 09:17:00 +0200
 DateTime.parse(date).strftime("%Y-%m-%dT%l:%M:%S%z")
 #=> 2016-07-01T 9:17:00+0200
 DateTime.parse(date).strftime("%I:%M:%S %p")
 #=> 09:17:00 AM
 DateTime.parse(date).strftime("%H:%M:%S")
 #=> 09:17:00
 DateTime.parse(date).strftime("%e %b %Y %H:%M:%S%p")
 #=>  1 Jul 2016 09:17:00AM
 DateTime.parse(date).strftime("%d.%m.%y")
 #=> 01.07.16
 DateTime.parse(date).strftime("%A, %d %b %Y %l:%M %p")
 #=> Friday, 01 Jul 2016  9:17 AM

Preventing HTML and Script injections in Javascript

Use this,

function restrict(elem){
  var tf = _(elem);
  var rx = new RegExp;
  if(elem == "email"){
       rx = /[ '"]/gi;
  }else if(elem == "search" || elem == "comment"){
    rx = /[^a-z 0-9.,?]/gi;
  }else{
      rx =  /[^a-z0-9]/gi;
  }
  tf.value = tf.value.replace(rx , "" );
}

On the backend, for java , Try using StringUtils class or a custom script.

public static String HTMLEncode(String aTagFragment) {
        final StringBuffer result = new StringBuffer();
        final StringCharacterIterator iterator = new
                StringCharacterIterator(aTagFragment);
        char character = iterator.current();
        while (character != StringCharacterIterator.DONE )
        {
            if (character == '<')
                result.append("&lt;");
            else if (character == '>')
                result.append("&gt;");
            else if (character == '\"')
                result.append("&quot;");
            else if (character == '\'')
                result.append("&#039;");
            else if (character == '\\')
                result.append("&#092;");
            else if (character == '&')
                result.append("&amp;");
            else {
            //the char is not a special one
            //add it to the result as is
                result.append(character);
            }
            character = iterator.next();
        }
        return result.toString();
    }

How to take MySQL database backup using MySQL Workbench?

For Workbench 6.0

Open MySql workbench. To take database backup you need to create New Server Instance(If not available) within Server Administration.

Steps to Create New Server Instance:

  1. Select New Server Instance option within Server Administrator.
  2. Provide connection details.

After creating new server instance , it will be available in Server Administration list. Double click on Server instance you have created OR Click on Manage Import/Export option and Select Server Instance.

Now, From DATA EXPORT/RESTORE select DATA EXPORT option,Select Schema and Schema Object for backup.

You can take generate backup file in different way as given below-

Q.1) Backup file(.sql) contains both Create Table statements and Insert into Table Statements

ANS:

  1. Select Start Export Option

Q.2) Backup file(.sql) contains only Create Table Statements, not Insert into Table statements for all tables

ANS:

  1. Select Skip Table Data(no-data) option

  2. Select Start Export Option

Q.3) Backup file(.sql) contains only Insert into Table Statements, not Create Table statements for all tables

ANS:

  1. Select Advance Option Tab, Within Tables Panel- select no-create info-Do not write CREATE TABLE statement that re-create each dumped table option.
  2. Select Start Export Option

For Workbench 6.3

  1. Click on Management tab at left side in Navigator Panel
  2. Click on Data Export Option
  3. Select Schema
  4. Select Tables
  5. Select required option from dropdown below the tables list as per your requirement
  6. Select Include Create schema checkbox
  7. Click on Advance option
  8. Select Complete insert checkbox in Inserts Panel
  9. Start Export Workbench 6.3 export

For Workbench 8.0

  1. Go to Server tab
  2. Go to Database Export

This opens up something like this

MySQL Workbench

  1. Select the schema to export in the Tables to export
  2. Click on Export to Self-Contained file
  3. Check if Advanced Options... are exactly as you want the export
  4. Click the button Start Export

Do you need to dispose of objects and set them to null?

Objects never go out of scope in C# as they do in C++. They are dealt with by the Garbage Collector automatically when they are not used anymore. This is a more complicated approach than C++ where the scope of a variable is entirely deterministic. CLR garbage collector actively goes through all objects that have been created and works out if they are being used.

An object can go "out of scope" in one function but if its value is returned, then GC would look at whether or not the calling function holds onto the return value.

Setting object references to null is unnecessary as garbage collection works by working out which objects are being referenced by other objects.

In practice, you don't have to worry about destruction, it just works and it's great :)

Dispose must be called on all objects that implement IDisposable when you are finished working with them. Normally you would use a using block with those objects like so:

using (var ms = new MemoryStream()) {
  //...
}

EDIT On variable scope. Craig has asked whether the variable scope has any effect on the object lifetime. To properly explain that aspect of CLR, I'll need to explain a few concepts from C++ and C#.

Actual variable scope

In both languages the variable can only be used in the same scope as it was defined - class, function or a statement block enclosed by braces. The subtle difference, however, is that in C#, variables cannot be redefined in a nested block.

In C++, this is perfectly legal:

int iVal = 8;
//iVal == 8
if (iVal == 8){
    int iVal = 5;
    //iVal == 5
}
//iVal == 8

In C#, however you get a a compiler error:

int iVal = 8;
if(iVal == 8) {
    int iVal = 5; //error CS0136: A local variable named 'iVal' cannot be declared in this scope because it would give a different meaning to 'iVal', which is already used in a 'parent or current' scope to denote something else
}

This makes sense if you look at generated MSIL - all the variables used by the function are defined at the start of the function. Take a look at this function:

public static void Scope() {
    int iVal = 8;
    if(iVal == 8) {
        int iVal2 = 5;
    }
}

Below is the generated IL. Note that iVal2, which is defined inside the if block is actually defined at function level. Effectively this means that C# only has class and function level scope as far as variable lifetime is concerned.

.method public hidebysig static void  Scope() cil managed
{
  // Code size       19 (0x13)
  .maxstack  2
  .locals init ([0] int32 iVal,
           [1] int32 iVal2,
           [2] bool CS$4$0000)

//Function IL - omitted
} // end of method Test2::Scope

C++ scope and object lifetime

Whenever a C++ variable, allocated on the stack, goes out of scope it gets destructed. Remember that in C++ you can create objects on the stack or on the heap. When you create them on the stack, once execution leaves the scope, they get popped off the stack and gets destroyed.

if (true) {
  MyClass stackObj; //created on the stack
  MyClass heapObj = new MyClass(); //created on the heap
  obj.doSomething();
} //<-- stackObj is destroyed
//heapObj still lives

When C++ objects are created on the heap, they must be explicitly destroyed, otherwise it is a memory leak. No such problem with stack variables though.

C# Object Lifetime

In CLR, objects (i.e. reference types) are always created on the managed heap. This is further reinforced by object creation syntax. Consider this code snippet.

MyClass stackObj;

In C++ this would create an instance on MyClass on the stack and call its default constructor. In C# it would create a reference to class MyClass that doesn't point to anything. The only way to create an instance of a class is by using new operator:

MyClass stackObj = new MyClass();

In a way, C# objects are a lot like objects that are created using new syntax in C++ - they are created on the heap but unlike C++ objects, they are managed by the runtime, so you don't have to worry about destructing them.

Since the objects are always on the heap the fact that object references (i.e. pointers) go out of scope becomes moot. There are more factors involved in determining if an object is to be collected than simply presence of references to the object.

C# Object references

Jon Skeet compared object references in Java to pieces of string that are attached to the balloon, which is the object. Same analogy applies to C# object references. They simply point to a location of the heap that contains the object. Thus, setting it to null has no immediate effect on the object lifetime, the balloon continues to exist, until the GC "pops" it.

Continuing down the balloon analogy, it would seem logical that once the balloon has no strings attached to it, it can be destroyed. In fact this is exactly how reference counted objects work in non-managed languages. Except this approach doesn't work for circular references very well. Imagine two balloons that are attached together by a string but neither balloon has a string to anything else. Under simple ref counting rules, they both continue to exist, even though the whole balloon group is "orphaned".

.NET objects are a lot like helium balloons under a roof. When the roof opens (GC runs) - the unused balloons float away, even though there might be groups of balloons that are tethered together.

.NET GC uses a combination of generational GC and mark and sweep. Generational approach involves the runtime favouring to inspect objects that have been allocated most recently, as they are more likely to be unused and mark and sweep involves runtime going through the whole object graph and working out if there are object groups that are unused. This adequately deals with circular dependency problem.

Also, .NET GC runs on another thread(so called finalizer thread) as it has quite a bit to do and doing that on the main thread would interrupt your program.

How to install XNA game studio on Visual Studio 2012?

There seems to be some confusion over how to get this set up for the Express version specifically. Using the Windows Desktop (WD) version of VS Express 2012, I followed the instructions in Steve B's and Rick Martin's answers with the modifications below.

  • In step 2 rather than copying to "C:\Program Files (x86)\Microsoft Visual Studio 11.0\Common7\IDE\Extensions\Microsoft\XNA Game Studio 4.0", copy to "C:\Program Files (x86)\Microsoft Visual Studio 11.0\Common7\IDE\WDExpressExtensions\Microsoft\XNA Game Studio 4.0"
  • In step 4, after making the changes also add the line <Edition>WDExpress</Edition> (you should be able to see where it makes sense)
  • In step 5, replace devenv.exe with WDExpress.exe
  • In Rick Martin's step, replace "%LocalAppData%\Microsoft\VisualStudio\11.0\Extensions" with "%LocalAppData%\Microsoft\WDExpress\11.0\Extensions"

I haven't done a lot of work since then, but I did manage to create a new game project and it seems fine so far.

Should operator<< be implemented as a friend or as a member function?

The signature:

bool operator<<(const obj&, const obj&);

Seems rather suspect, this does not fit the stream convention nor the bitwise convention so it looks like a case of operator overloading abuse, operator < should return bool but operator << should probably return something else.

If you meant so say:

ostream& operator<<(ostream&, const obj&); 

Then since you can't add functions to ostream by necessity the function must be a free function, whether it a friend or not depends on what it has to access (if it doesn't need to access private or protected members there's no need to make it friend).

C# Wait until condition is true

After digging a lot of stuff, finally, I came up with a good solution that doesn't hang the CI :) Suit it to your needs!

public static Task WaitUntil<T>(T elem, Func<T, bool> predicate, int seconds = 10)
{
    var tcs = new TaskCompletionSource<int>();
    using(var cancellationTokenSource = new CancellationTokenSource(TimeSpan.FromSeconds(seconds)))
    {
        cancellationTokenSource.Token.Register(() =>
        {
            tcs.SetException(
                new TimeoutException($"Waiting predicate {predicate} for {elem.GetType()} timed out!"));
            tcs.TrySetCanceled();
        });

        while(!cancellationTokenSource.IsCancellationRequested)
        {
            try
            {
                if (!predicate(elem))
                {
                    continue;
                }
            }
            catch(Exception e)
            {
                tcs.TrySetException(e);
            }

            tcs.SetResult(0);
            break;
        }

        return tcs.Task;
    }
}

Way to read first few lines for pandas dataframe

I think you can use the nrows parameter. From the docs:

nrows : int, default None

    Number of rows of file to read. Useful for reading pieces of large files

which seems to work. Using one of the standard large test files (988504479 bytes, 5344499 lines):

In [1]: import pandas as pd

In [2]: time z = pd.read_csv("P00000001-ALL.csv", nrows=20)
CPU times: user 0.00 s, sys: 0.00 s, total: 0.00 s
Wall time: 0.00 s

In [3]: len(z)
Out[3]: 20

In [4]: time z = pd.read_csv("P00000001-ALL.csv")
CPU times: user 27.63 s, sys: 1.92 s, total: 29.55 s
Wall time: 30.23 s

Multiple GitHub Accounts & SSH Config

As a complement of @stefano 's answer, It is better to use command with -f when generate a new SSH key for another account,

ssh-keygen -t rsa -f ~/.ssh/id_rsa_work -C "[email protected]"

Since id_rsa_work file doesn't exist in path ~/.ssh/, and I create this file manually, and it doesn't work :(

Converting a pointer into an integer

Several answers have pointed at uintptr_t and #include <stdint.h> as 'the' solution. That is, I suggest, part of the answer, but not the whole answer. You also need to look at where the function is called with the message ID of FOO.

Consider this code and compilation:

$ cat kk.c
#include <stdio.h>
static void function(int n, void *p)
{
    unsigned long z = *(unsigned long *)p;
    printf("%d - %lu\n", n, z);
}

int main(void)
{
    function(1, 2);
    return(0);
}
$ rmk kk
        gcc -m64 -g -O -std=c99 -pedantic -Wall -Wshadow -Wpointer-arith \
            -Wcast-qual -Wstrict-prototypes -Wmissing-prototypes \
            -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE kk.c -o kk 
kk.c: In function 'main':
kk.c:10: warning: passing argument 2 of 'func' makes pointer from integer without a cast
$

You will observe that there is a problem at the calling location (in main()) — converting an integer to a pointer without a cast. You are going to need to analyze your function() in all its usages to see how values are passed to it. The code inside my function() would work if the calls were written:

unsigned long i = 0x2341;
function(1, &i);

Since yours are probably written differently, you need to review the points where the function is called to ensure that it makes sense to use the value as shown. Don't forget, you may be finding a latent bug.

Also, if you are going to format the value of the void * parameter (as converted), look carefully at the <inttypes.h> header (instead of stdint.hinttypes.h provides the services of stdint.h, which is unusual, but the C99 standard says [t]he header <inttypes.h> includes the header <stdint.h> and extends it with additional facilities provided by hosted implementations) and use the PRIxxx macros in your format strings.

Also, my comments are strictly applicable to C rather than C++, but your code is in the subset of C++ that is portable between C and C++. The chances are fair to good that my comments apply.

How to add empty spaces into MD markdown readme on GitHub?

I'm surprised no one mentioned the HTML entities &ensp; and &emsp; which produce horizontal white space equivalent to the characters n and m, respectively. If you want to accumulate horizontal white space quickly, those are more efficient than &nbsp;.

  1. no space
  2.  &nbsp;
  3. &ensp;
  4. &emsp;

Along with <space> and &thinsp;, these are the five entities HTML provides for horizontal white space.

Note that except for &nbsp;, all entities allow breaking. Whatever text surrounds them will wrap to a new line if it would otherwise extend beyond the container boundary. With &nbsp; it would wrap to a new line as a block even if the text before &nbsp; could fit on the previous line.

Depending on your use case, that may be desired or undesired. For me, unless I'm dealing with things like names (John&nbsp;Doe), addresses or references (see eq.&nbsp;5), breaking as a block is usually undesired.

How to determine when a Git branch was created?

Try this

  git for-each-ref --format='%(committerdate) %09 %(authorname) %09 %(refname)'

How do I add a foreign key to an existing SQLite table?

In case somebody else needs info on SQLiteStudio, you can easily do it form it's GUI.

Double-click on the column and double-click foreign key row, then tick foreign key and click configure. You can add the reference column, then click OK in every window.

Finally click on the green tick to commit changes in the structure.

BE AWARE THAT THESE STEPS CREATE SQL SCRIPTS THAT DELETES THE TABLE AND RECREATES IT!!

Backup your data from the database.

SQL Server converting varbinary to string

I know this is an old question, but here is an alternative approach that I have found more useful in some situations. I believe the master.dbo.fn_varbintohexstr function has been available in SQL Server at least since SQL2K. Adding it here just for completeness. Some readers may also find it instructive to look at the source code of this function.

declare @source varbinary(max);
set @source = 0x21232F297A57A5A743894A0E4A801FC3;
select varbin_source = @source
,string_result = master.dbo.fn_varbintohexstr (@source)

Java 8, Streams to find the duplicate elements

Basic example. First-half builds the frequency-map, second-half reduces it to a filtered list. Probably not as efficient as Dave's answer, but more versatile (like if you want to detect exactly two etc.)

List<Integer> duplicates = IntStream.of( 1, 2, 3, 2, 1, 2, 3, 4, 2, 2, 2 )
   .boxed()
   .collect( Collectors.groupingBy( Function.identity(), Collectors.counting() ) )
   .entrySet()
   .stream()
   .filter( p -> p.getValue() > 1 )
   .map( Map.Entry::getKey )
   .collect( Collectors.toList() );

How to use PHP string in mySQL LIKE query?

You have the syntax wrong; there is no need to place a period inside a double-quoted string. Instead, it should be more like

$query = mysql_query("SELECT * FROM table WHERE the_number LIKE '$prefix%'");

You can confirm this by printing out the string to see that it turns out identical to the first case.

Of course it's not a good idea to simply inject variables into the query string like this because of the danger of SQL injection. At the very least you should manually escape the contents of the variable with mysql_real_escape_string, which would make it look perhaps like this:

$sql = sprintf("SELECT * FROM table WHERE the_number LIKE '%s%%'",
               mysql_real_escape_string($prefix));
$query = mysql_query($sql);

Note that inside the first argument of sprintf the percent sign needs to be doubled to end up appearing once in the result.

Is it possible to use JS to open an HTML select to show its option list?

<select id="myDropDown">
  <option>html5</option>
  <option>javascript</option>
  <option>jquery</option>
  <option>css</option>
  <option>sencha</option>
</select>

By jQuery:

var myDropDown=$("#myDropDown");
var length = $('#myDropDown> option').length;
//open dropdown
myDropDown.attr('size',length);
//close dropdown
myDropDown.attr('size',0);

By javascript:

var myDropDown=document.getElementById("myDropDown");
var length = myDropDown.options.length;
//open dropdown
myDropDown.size = length;
//close dropdown
myDropDown.size = 0;

Copied from: Open close select

Where does git config --global get written to?

.gitconfig file location

macOS testing OK

global

# global config
$ cd ~/.gitconfig

# view global config
$ git config --global -l

local

# local config
$ cd .git/config

# view local config
$ git config -l


maybe a bonus for you:Vim or VSCode for edit git config


# open config with Vim

# global config
$ vim ~/.gitconfig

# local config
$ vim .git/config


# open config with VSCode

# global config
$ code ~/.gitconfig

# local config
$ code .git/config

How to destroy a DOM element with jQuery?

Not sure if it's just me, but using .remove() doesn't seem to work if you are selecting by an id.

Ex: $("#my-element").remove();

I had to use the element's class instead, or nothing happened.

Ex: $(".my-element").remove();

What is considered a good response time for a dynamic, personalized web application?

Not only does it depend on what keeps your users happy, but how much development time do you have? What kind of resources can you throw at the problem (software, hardware, and people)?

I don't mind a couple-few second delay for hosted applications if they're doing something "complex". If it's really simple, delays bother me.

get data from mysql database to use in javascript

To do with javascript you could do something like this:

<script type="Text/javascript">
var text = <?= $text_from_db; ?>
</script>

Then you can use whatever you want in your javascript to put the text var into the textbox.

Remove object from a list of objects in python

if you wanna remove the last one just do your_list.pop(-1) if you wanna remove the first one your_list.pop(0) or any index you wish to remove

How to get JavaScript caller function line number? How to get JavaScript caller source URL?

This is often achieved by throwing an error from the current context; then analyzing error object for properties like lineNumber and fileName (which some browsers have)

function getErrorObject(){
  try { throw Error('') } catch(err) { return err; }
}

var err = getErrorObject();

err.fileName;
err.lineNumber; // or `err.line` in WebKit

Don't forget that callee.caller property is deprecated (and was never really in ECMA 3rd ed. in the first place).

Also remember that function decompilation is specified to be implementation dependent and so might yield quite unexpected results. I wrote about it here and here.

HTML 5: Is it <br>, <br/>, or <br />?

  1. If you are outputting HTML on a regular website you can use <br> or <br/>, both are valid anytime you are serving HTML5 as text/html.

  2. If you are serving HTML5 as XHTML (i.e. content type application/xhtml+xml, with an XML declaration) then you must use a self closing tag like so: <br/>.

    If you don't the some browsers may flat out refuse to render your page (Firefox in particular is very strict about rendering only valid xhtml+xml pages).

    As noted in 1. <br/> is also valid for HTML5 that happens to be generated as XML but served as a regular text/html without an XML declaration (such as from an XSL Transform that generates web pages, or something similar).

To clear up confusion: Putting a space before the slash isn't required in HTML5 and doesn't make any difference to how the page is rendered (if anyone can cite an example I'll retract this, but I don't believe it's true - but IE certainly does a lot of other odd things with all forms of <br> tags).

The excellent validator at http://validator.w3.org is really helpful for checking what's valid (although I'm not sure you can rely on it to also check content-type).

How much data can a List can hold at the maximum?

Numbering an items in the java array should start from zero. This was i think we can have access to Integer.MAX_VALUE+1 an items.

Using wget to recursively fetch a directory with arbitrary files in it

wget -r http://mysite.com/configs/.vim/

works for me.

Perhaps you have a .wgetrc which is interfering with it?

Laravel 4: Redirect to a given url

Both Redirect::to() and Redirect::away() should work.

Difference

Redirect::to() does additional URL checks and generations. Those additional steps are done in Illuminate\Routing\UrlGenerator and do the following, if the passed URL is not a fully valid URL (even with protocol):

Determines if URL is secure
rawurlencode() the URL
trim() URL

src : https://medium.com/@zwacky/laravel-redirect-to-vs-redirect-away-dd875579951f

fatal error LNK1104: cannot open file 'kernel32.lib'

Change the platform toolset to: "Windows7.1SDK" under project properties->configuration properties->general

Kotlin - Property initialization using "by lazy" vs. "lateinit"

Everything is correct above, but one of facts simple explanation LAZY----There are cases when you want to delay the creation of an instance of your object until its first usage. This technique is known as lazy initialization or lazy instantiation. The main purpose of lazy initialization is to boost performance and reduce your memory footprint. If instantiating an instance of your type carries a large computational cost and the program might end up not actually using it, you would want to delay or even avoid wasting CPU cycles.

AngularJS multiple filter with custom filter function

Hope below answer in this link will help, Multiple Value Filter

And take a look into the fiddle with example

arrayOfObjectswithKeys | filterMultiple:{key1:['value1','value2','value3',...etc],key2:'value4',key3:[value5,value6,...etc]}

fiddle

Installing a pip package from within a Jupyter Notebook not working

This worked for me in Jupyter nOtebook /Mac Platform /Python 3 :

import sys
!{sys.executable} -m pip install -r requirements.txt

Render partial view with dynamic model in Razor view engine and ASP.NET MVC 3

Here's a way to pass a dynamic object to a view (or partial view)

Add the following class anywhere in your solution (use System namespace, so its ready to use without having to add any references) -

    namespace System
    {
        public static class ExpandoHelper
        {
            public static ExpandoObject ToExpando(this object anonymousObject)
            {
                IDictionary<string, object> anonymousDictionary = HtmlHelper.AnonymousObjectToHtmlAttributes(anonymousObject);
                IDictionary<string, object> expando = new ExpandoObject();
                foreach (var item in anonymousDictionary)
                    expando.Add(item);
                return (ExpandoObject)expando;
            }

        }
    }

When you send the model to the view, convert it to Expando :

    return View(new {x=4, y=6}.ToExpando());

Cheers

How do android screen coordinates work?

This picture will remove everyone's confusion hopefully which is collected from there.

Android screen coordinate

How do I use MySQL through XAMPP?

XAMPP Apache + MariaDB + PHP + Perl (X -any OS)

  • After successful installation execute xampp-control.exe in XAMPP folder
  • Start Apache and MySQL enter image description here

  • Open browser and in url type localhost or 127.0.0.1

  • then you are welcomed with dashboard

By default your port is listing with 80.If you want you can change it to your desired port number in httpd.conf file.(If port 80 is already using with other app then you have to change it).

For example you changed port number 80 to 8090 then you can run as 'localhost:8090' or '127.0.0.1:8090'

Iterating through all the cells in Excel VBA or VSTO 2005

In Excel VBA, this function will give you the content of any cell in any worksheet.

Function getCellContent(Byref ws As Worksheet, ByVal rowindex As Integer, ByVal colindex As Integer) as String
    getCellContent = CStr(ws.Cells(rowindex, colindex))
End Function

So if you want to check the value of cells, just put the function in a loop, give it the reference to the worksheet you want and the row index and column index of the cell. Row index and column index both start from 1, meaning that cell A1 will be ws.Cells(1,1) and so on.

Output (echo/print) everything from a PHP Array

For nice & readable results, use this:

function printVar($var) {
    echo '<pre>';
    var_dump($var); 
    echo '</pre>';
}

The above function will preserve the original formatting, making it (more)readable in a web browser.

Read int values from a text file in C

How about this?

fscanf(file,"%d %d %d %d %d %d %d",&line1_1,&line1_2, &line1_3, &line2_1, &line2_2, &line3_1, &line3_2); 

In this case spaces in fscanf match multiple occurrences of any whitespace until the next token in found.

How do you change the launcher logo of an app in Android Studio?

Here are my steps for the task:

  1. Create PNG image file of size 512x512 pixels
  2. In Android Studio, in project view, highlight a mipmap directory
  3. In menu, go to File>New>Image Asset
  4. Click Image Button in Asset type button row
  5. Click on 3 Dot Box at right of Path Box.
  6. Drag image to source asset box
  7. Click Next (Note: Existing launcher files will be overwritten)
  8. Click Finish

How to connect to a remote Windows machine to execute commands using python?

Maybe you can use SSH to connect to a remote server.

Install freeSSHd on your windows server.

SSH Client connection Code:

import paramiko

hostname = "your-hostname"
username = "your-username"
password = "your-password"
cmd = 'your-command'

try:
    ssh = paramiko.SSHClient()
    ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy())
    ssh.connect(hostname,username=username,password=password)
    print("Connected to %s" % hostname)
except paramiko.AuthenticationException:
    print("Failed to connect to %s due to wrong username/password" %hostname)
    exit(1)
except Exception as e:
    print(e.message)    
    exit(2)

Execution Command and get feedback:

try:
    stdin, stdout, stderr = ssh.exec_command(cmd)
except Exception as e:
    print(e.message)

err = ''.join(stderr.readlines())
out = ''.join(stdout.readlines())
final_output = str(out)+str(err)
print(final_output)

GroupBy pandas DataFrame and select most common value

A slightly clumsier but faster approach for larger datasets involves getting the counts for a column of interest, sorting the counts highest to lowest, and then de-duplicating on a subset to only retain the largest cases. The code example is following:

>>> import pandas as pd
>>> source = pd.DataFrame(
        {
            'Country': ['USA', 'USA', 'Russia', 'USA'], 
            'City': ['New-York', 'New-York', 'Sankt-Petersburg', 'New-York'],
            'Short name': ['NY', 'New', 'Spb', 'NY']
        }
    )
>>> grouped_df = source\
        .groupby(['Country','City','Short name'])[['Short name']]\
        .count()\
        .rename(columns={'Short name':'count'})\
        .reset_index()\
        .sort_values('count', ascending=False)\
        .drop_duplicates(subset=['Country', 'City'])\
        .drop('count', axis=1)
>>> print(grouped_df)
  Country              City Short name
1     USA          New-York         NY
0  Russia  Sankt-Petersburg        Spb

Notification Icon with the new Firebase Cloud Messaging system

atm they are working on that issue https://github.com/firebase/quickstart-android/issues/4

when you send a notification from the Firebase console is uses your app icon by default, and the Android system will turn that icon solid white when in the notification bar.

If you are unhappy with that result you should implement FirebaseMessagingService and create the notifications manually when you receive a message. We are working on a way to improve this but for now that's the only way.

edit: with SDK 9.8.0 add to AndroidManifest.xml

<meta-data android:name="com.google.firebase.messaging.default_notification_icon" android:resource="@drawable/my_favorite_pic"/>

Save a file in json format using Notepad++

You can do using a simple notepad and save as FILENAME.json

That's all.

use jQuery's find() on JSON object

For one dimension json you can use this:

function exist (json, modulid) {
    var ret = 0;
    $(json).each(function(index, data){
        if(data.modulId == modulid)
            ret++;
    })
    return ret > 0;
}

Python: Assign Value if None Exists

Here is the easiest way I use, hope works for you,

var1 = var1 or 4

This assigns 4 to var1 only if var1 is None , False or 0

How to Refresh a Component in Angular

Other way to refresh (hard way) a page in angular 2 like this it's look like f5

import { Location } from '@angular/common';

constructor(private location: Location) {}

pageRefresh() {
   location.reload();
}

OpenSSL Command to check if a server is presenting a certificate

I encountered the write:errno=104 attempting to test connecting to an SSL-enabled RabbitMQ broker port with openssl s_client.

The issue turned out to be simply that the user RabbitMQ was running as did not have read permissions on the certificate file. There was little-to-no useful logging in RabbitMQ.

MySQL - SELECT all columns WHERE one column is DISTINCT

The problem comes from instinctively believing that DISTINCT is a local pre-modifier for a column.

Hence, you "should" be able to type

XXbadXX SELECT col1, DISTINCT col2 FROM mytable XXbadXX

and have it return unique values for col2. Sadly, no. DISTINCT is actually a global post-modifier for SELECT, that is, as opposed to SELECT ALL (returning all answers) it is SELECT DISTINCT (returning all unique answers). So a single DISTINCT acts on ALL the columns that you give it.

This makes it real hard to use DISTINCT on a single column, while getting the other columns, without doing major extremely ugly backflips.

The correct answer is to use a GROUP BY on the columns that you want to have unique answers: SELECT col1, col2 FROM mytable GROUP BY col2 will give you arbitrary unique col2 rows, with their col1 data as well.

Class has been compiled by a more recent version of the Java Environment

Go to Project section, click on properties > then to Java compiler > check compiler compliance level is 1.8 , or there should be no yellow warning at bottom

how to convert Lower case letters to upper case letters & and upper case letters to lower case letters

If you look at characters a-z, you'll see that all of them have the 6th bit is set to 1. Where in A-Z 6th bit is not set.

A = 1000001    a = 1100001
B = 1000010    b = 1100010
C = 1000011    c = 1100011
D = 1000100    d = 1100100     
...
Z = 1011010    z = 1111010

So all we need to do is to iterate through each character from a given string and then do XOR(^) with 32. In this way, the 6th bit can swap.

Look at the below code for simply changing the string case without using any if-else conditions.

public final class ChangeStringCase {
    public static void main(String[] args) {
        String str = "Hello World";
        for (int i = 0; i < str.length(); i++) {
            char ans = (char)(str.charAt(i) ^ 32);
            System.out.print(ans); // Final Output: hELLO wORLD
        }
    }
}

Time Complexity: O(N) where N = Length of the string.

Space Complexity: O(1)

Check if a class is derived from a generic class

Try this code

static bool IsSubclassOfRawGeneric(Type generic, Type toCheck) {
    while (toCheck != null && toCheck != typeof(object)) {
        var cur = toCheck.IsGenericType ? toCheck.GetGenericTypeDefinition() : toCheck;
        if (generic == cur) {
            return true;
        }
        toCheck = toCheck.BaseType;
    }
    return false;
}

Safely remove migration In Laravel

 php artisan migrate:fresh

Should do the job, if you are in development and the desired outcome is to start all over.

In production, that maybe not the desired thing, so you should be adverted. (The migrate:fresh command will drop all tables from the database and then execute the migrate command).

How to mkdir only if a directory does not already exist?

mkdir foo works even if the directory exists. To make it work only if the directory named "foo" does not exist, try using the -p flag.

Example:

mkdir -p foo

This will create the directory named "foo" only if it does not exist. :)

Batch file to copy files from one folder to another folder

You can use esentutl to copy (mainly big) files with a progress bar:

esentutl /y "my.file" /d "another.file" /o

the progress bar looks like this:

enter image description here

Proper use of const for defining functions in JavaScript

There are special cases where arrow functions just won't do the trick:

  1. If we're changing a method of an external API, and need the object's reference.

  2. If we need to use special keywords that are exclusive to the function expression: arguments, yield, bind etc. For more information: Arrow function expression limitations

Example:

I assigned this function as an event handler in the Highcharts API. It's fired by the library, so the this keyword should match a specific object.

export const handleCrosshairHover = function (proceed, e) {
  const axis = this; // axis object
  proceed.apply(axis, Array.prototype.slice.call(arguments, 1)); // method arguments
};

With an arrow function, this would match the declaration scope, and we won't have access to the API obj:

export const handleCrosshairHover = (proceed, e) => {
  const axis = this; // this = undefined
  proceed.apply(axis, Array.prototype.slice.call(arguments, 1)); // compilation error
};

Converting a number with comma as decimal point to float

Assuming they are in a file or array just do the replace as a batch (i.e. on all at once):

$input = str_replace(array('.', ','), array('', '.'), $input); 

and then process the numbers from there taking full advantage of PHP's loosely typed nature.

How to make for loops in Java increase by increments other than 1

If you have a for loop like this:

for(j = 0; j<=90; j++){}

In this loop you are using shorthand provided by java language which means a postfix operator(use-then-change) which is equivalent to j=j+1 , so the changed value is initialized and used for next operation.

for(j = 0; j<=90; j+3){}

In this loop you are just increment your value by 3 but not initializing it back to j variable, so the value of j remains changed.

"Rate This App"-link in Google Play store app on the phone

Here is my version using the BuildConfig class:

Intent marketIntent = new Intent(Intent.ACTION_VIEW, uri);

marketIntent.addFlags(Intent.FLAG_ACTIVITY_NO_HISTORY | Intent.FLAG_ACTIVITY_MULTIPLE_TASK);

if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
    marketIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_DOCUMENT);
}

try {
    startActivity(marketIntent);
} catch (ActivityNotFoundException e) {
    startActivity(new Intent(Intent.ACTION_VIEW, Uri.parse("https://play.google.com/store/apps/details?id=" + BuildConfig.APPLICATION_ID)));
}

What's the best way to identify hidden characters in the result of a query in SQL Server (Query Analyzer)?

I have faced the same problem with a character that I never managed to match with a where query - CHARINDEX, LIKE, REPLACE, etc. did not work. Then I have used a brute force solution which is awful, heavy but works:

Step 1: make a copy of the complete data set - keep track of the original names with an source_id referencing the pk of the source table (and keep this source id in all the subsequent tables). Step 2: LTRIM RTRIM the data, and replace all double spaces, tab, etc (basically all the CHAR(1) to CHAR(32) by one space. Lowercase the whole set as well. Step 3: replace all the special characters that you know (get the list of all the quotes, double quotes, etc.) by something from a-z (I suggest z). Basically replace everything that is not standard English characters by a z (using nested REPLACE of REPLACE in a loop). Step 4: split by word into a second copy, where each word is in a separate row - the split is a SUBSTRING based on the position of the space characters - at this point, we should miss the ones where there's a hidden space that we did not catche earlier. Step 5: split each word into a third copy, where each letter is in a separate row (I know it makes a very large table) - keep track of the charindex of each letter in a separate column. Step 6: Select everything in the above table which is not LIKE [a-z]. This is the list of the unidentified characters we want to exclude.

From the output of step 6 we have enough data to make a series of substring of the source to select everything but the unknown character we want to exclude.

Note 1: there are smart ways to optimize this, depending on the size of the original expression (steps 4, 5 and 6 can be made in one go).

Note 2: this is not very fast, but the fastest way to get this done for a large data set, because the split of lines into words and words into letters is made by substring, which slices all the table into one character slices. However, this is quite heavy to build. With a smaller set, it may be enough to parse each record one by one and search for character which is not in a list of all English characters plus all special characters.

Ignore .pyc files in git repository

Put it in .gitignore. But from the gitignore(5) man page:

  ·   If the pattern does not contain a slash /, git treats it as a shell
       glob pattern and checks for a match against the pathname relative
       to the location of the .gitignore file (relative to the toplevel of
       the work tree if not from a .gitignore file).

  ·   Otherwise, git treats the pattern as a shell glob suitable for
       consumption by fnmatch(3) with the FNM_PATHNAME flag: wildcards in
       the pattern will not match a / in the pathname. For example,
       "Documentation/*.html" matches "Documentation/git.html" but not
       "Documentation/ppc/ppc.html" or
       "tools/perf/Documentation/perf.html".

So, either specify the full path to the appropriate *.pyc entry, or put it in a .gitignore file in any of the directories leading from the repository root (inclusive).

A failure occurred while executing com.android.build.gradle.internal.tasks

search your code you must be referring to color in color.xml in an xml drawable. go and give hex code instead of referencing....

Example: in drawable.xml you must have called

android:fillColor="@color/blue"

change it to android:fillColor="#ffaacc" hope it solve your problem...

Convert dateTime to ISO format yyyy-mm-dd hh:mm:ss in C#

To add a little bit more information that confused me; I had always thought the same result could be achieved like so;

theDate.ToString("yyyy-MM-dd HH:mm:ss")

However, If your Current Culture doesn't use a colon(:) as the hour separator, and instead uses a full-stop(.) it could return as follow:

2009-06-15 13.45.30

Just wanted to add why the answer provided needs to be as it is;

theDate.ToString("yyyy-MM-dd HH':'mm':'ss")

:-)

outline on only one border

The great thing about HTML/CSS is that there's usually more than one way to achieve the same effect. Here's another solution that does what you want:

<nav id="menu1">
    <ul>
        <li><a href="#">Menu Link 1</a></li>
        <li><a href="#">Menu Link 2</a></li>
    </ul>
</nav>

nav {
    background:#666;
    margin:1em;
    padding:.5em 0;
}
nav ul {
    border-top:1px dashed #fff;
    list-style:none;
    padding:.5em;
}
nav ul li {
    display:inline-block;
}
nav ul li a {
    color:#fff;
}

http://jsfiddle.net/10basetom/uCX3G/1/

How can I get the name of an html page in Javascript?

Current page: It's possible to do even shorter. This single line sound more elegant to find the current page's file name:

var fileName = location.href.split("/").slice(-1); 

or...

var fileName = location.pathname.split("/").slice(-1)

This is cool to customize nav box's link, so the link toward the current is enlighten by a CSS class.

JS:

$('.menu a').each(function() {
    if ($(this).attr('href') == location.href.split("/").slice(-1)){ $(this).addClass('curent_page'); }
});

CSS:

a.current_page { font-size: 2em; color: red; }

How to prevent caching of my Javascript file?

You can add a random (or datetime string) as query string to the url that points to your script. Like so:

<script type="text/javascript" src="test.js?q=123"></script> 

Every time you refresh the page you need to make sure the value of 'q' is changed.

using extern template (C++11)

You should only use extern template to force the compiler to not instantiate a template when you know that it will be instantiated somewhere else. It is used to reduce compile time and object file size.

For example:

// header.h

template<typename T>
void ReallyBigFunction()
{
    // Body
}

// source1.cpp

#include "header.h"
void something1()
{
    ReallyBigFunction<int>();
}

// source2.cpp

#include "header.h"
void something2()
{
    ReallyBigFunction<int>();
}

This will result in the following object files:

source1.o
    void something1()
    void ReallyBigFunction<int>()    // Compiled first time

source2.o
    void something2()
    void ReallyBigFunction<int>()    // Compiled second time

If both files are linked together, one void ReallyBigFunction<int>() will be discarded, resulting in wasted compile time and object file size.

To not waste compile time and object file size, there is an extern keyword which makes the compiler not compile a template function. You should use this if and only if you know it is used in the same binary somewhere else.

Changing source2.cpp to:

// source2.cpp

#include "header.h"
extern template void ReallyBigFunction<int>();
void something2()
{
    ReallyBigFunction<int>();
}

Will result in the following object files:

source1.o
    void something1()
    void ReallyBigFunction<int>() // compiled just one time

source2.o
    void something2()
    // No ReallyBigFunction<int> here because of the extern

When both of these will be linked together, the second object file will just use the symbol from the first object file. No need for discard and no wasted compile time and object file size.

This should only be used within a project, like in times when you use a template like vector<int> multiple times, you should use extern in all but one source file.

This also applies to classes and function as one, and even template member functions.

Fetch first element which matches criteria

When you write a lambda expression, the argument list to the left of -> can be either a parenthesized argument list (possibly empty), or a single identifier without any parentheses. But in the second form, the identifier cannot be declared with a type name. Thus:

this.stops.stream().filter(Stop s-> s.getStation().getName().equals(name));

is incorrect syntax; but

this.stops.stream().filter((Stop s)-> s.getStation().getName().equals(name));

is correct. Or:

this.stops.stream().filter(s -> s.getStation().getName().equals(name));

is also correct if the compiler has enough information to figure out the types.

R: invalid multibyte string

If you want an R solution, here's a small convenience function I sometimes use to find where the offending (multiByte) character is lurking. Note that it is the next character to what gets printed. This works because print will work fine, but substr throws an error when multibyte characters are present.

find_offending_character <- function(x, maxStringLength=256){  
  print(x)
  for (c in 1:maxStringLength){
    offendingChar <- substr(x,c,c)
    #print(offendingChar) #uncomment if you want the indiv characters printed
    #the next character is the offending multibyte Character
  }    
}

string_vector <- c("test", "Se\x96ora", "works fine")

lapply(string_vector, find_offending_character)

I fix that character and run this again. Hope that helps someone who encounters the invalid multibyte string error.

What characters are valid for JavaScript variable names?

Javascript variables can have letters, digits, dollar signs ($) and underscores (_). They can't start with digits.

Usually libraries use $ and _ as shortcuts for functions that you'll be using everywhere. Although the names $ or _ aren't meaningful, they're useful for their shortness and since you'll be using the function everywhere you're expected to know what they mean.

If your library doesn't consist on getting a single function being used everywhere, I'd recommend that you use more meaningful names as those will help you and others understand what your code is doing without necessarily compromising the source code niceness.

You could for instance take a look at the awesome DateJS library and at the syntatic sugar it allows without the need of any symbol or short-named variables.

You should first get your code to be practical, and only after try making it pretty.

Convert an object to an XML string

This is my solution, for any list object you can use this code for convert to xml layout. KeyFather is your principal tag and KeySon is where start your Forech.

public string BuildXml<T>(ICollection<T> anyObject, string keyFather, string keySon)
    {
        var settings = new XmlWriterSettings
        {
            Indent = true
        };
        PropertyDescriptorCollection props = TypeDescriptor.GetProperties(typeof(T));
        StringBuilder builder = new StringBuilder();
        using (XmlWriter writer = XmlWriter.Create(builder, settings))
        {
            writer.WriteStartDocument();
            writer.WriteStartElement(keyFather);
            foreach (var objeto in anyObject)
            {
                writer.WriteStartElement(keySon);
                foreach (PropertyDescriptor item in props)
                {
                    writer.WriteStartElement(item.DisplayName);
                    writer.WriteString(props[item.DisplayName].GetValue(objeto).ToString());
                    writer.WriteEndElement();
                }
                writer.WriteEndElement();
            }
            writer.WriteFullEndElement();
            writer.WriteEndDocument();
            writer.Flush();
            return builder.ToString();
        }
    }

Python Create unix timestamp five minutes in the future

You can use datetime.strftime to get the time in Epoch form, using the %s format string:

def expires():
    future = datetime.datetime.now() + datetime.timedelta(seconds=5*60)
    return int(future.strftime("%s"))

Note: This only works under linux, and this method doesn't work with timezones.

Vim multiline editing like in sublimetext?

Ctrl-v ................ start visual block selection
6j .................... go down 6 lines
I" .................... inserts " at the beginning
<Esc><Esc> ............ finishes start
2fdl. ................. second 'd' l (goes right) . (repeats insertion)

How to access a dictionary element in a Django template?

To echo / extend upon Jeff's comment, what I think you should aim for is simply a property in your Choice class that calculates the number of votes associated with that object:

class Choice(models.Model):
    text = models.CharField(max_length=200)

    def calculateVotes(self):
        return Vote.objects.filter(choice=self).count()

    votes = property(calculateVotes)

And then in your template, you can do:

{% for choice in choices %}
    {{choice.choice}} - {{choice.votes}} <br />
{% endfor %}

The template tag, is IMHO a bit overkill for this solution, but it's not a terrible solution either. The goal of templates in Django is to insulate you from code in your templates and vice-versa.

I'd try the above method and see what SQL the ORM generates as I'm not sure off the top of my head if it will pre-cache the properties and just create a subselect for the property or if it will iteratively / on-demand run the query to calculate vote count. But if it generates atrocious queries, you could always populate the property in your view with data you've collected yourself.

Java Reflection: How to get the name of a variable?

It is not possible at all. Variable names aren't communicated within Java (and might also be removed due to compiler optimizations).

EDIT (related to comments):

If you step back from the idea of having to use it as function parameters, here's an alternative (which I wouldn't use - see below):

public void printFieldNames(Object obj, Foo... foos) {
    List<Foo> fooList = Arrays.asList(foos);
    for(Field field : obj.getClass().getFields()) {
         if(fooList.contains(field.get()) {
              System.out.println(field.getName());
         }
    }
}

There will be issues if a == b, a == r, or b == r or there are other fields which have the same references.

EDIT now unnecessary since question got clarified

Select default option value from typescript angular 6

<select class="form-control" [value]="defaultSelectedCurrency" formControlName="currency">
<option *ngFor="let item of currency" [value]="item.value" [selected]="item.isSelected">{{item.key}}</option>
</select>

currency = [
    { key: 'USD', value: 'USD', isSelected: true },
    { key: 'AUD', value: 'AUD', isSelected: false }
  ];
  defaultSelectedCurrency: string;

 ngOnInit() {
    this.defaultSelectedCurrency = this.currency[0].value;
}

How to write log base(2) in c/c++

All the above answers are correct. This answer of mine below can be helpful if someone needs it. I have seen this requirement in many questions which we are solving using C.

log2 (x) = logy (x) / logy (2)

However, if you are using C language and you want the result in integer, you can use the following:

int result = (int)(floor(log(x) / log(2))) + 1;

Hope this helps.

Read String line by line

Since Java 11, there is a new method String.lines:

/**
 * Returns a stream of lines extracted from this string,
 * separated by line terminators.
 * ...
 */
public Stream<String> lines() { ... }

Usage:

"line1\nline2\nlines3"
    .lines()
    .forEach(System.out::println);

ActionBarCompat: java.lang.IllegalStateException: You need to use a Theme.AppCompat

I just get my application move from ActionBarSherlock to ActionBarCompat. Try declare your old theme like this:

<style name="Theme.Event" parent="Theme.AppCompat">

Then set the theme in your AndroidManifest.xml:

<application
    android:debuggable="true"
    android:name=".activity.MyApplication"
    android:allowBackup="true"
    android:icon="@drawable/ic_launcher"
    android:label="@string/app_name"
    android:theme="@style/Theme.Event.Home"
     >

C compile error: Id returned 1 exit status

You may compiling your program while another program may be running in background. Firstly, see if another program is running .Close it and then try ro compile.

ERROR 1115 (42000): Unknown character set: 'utf8mb4'

As some suggested here, replacing utf8mb4 with utf8 will help you resolve the issue. IMHO, I used sed to find and replace them to avoid losing data. In addition, opening a large file into any graphical editor is potential pain. My MySQL data grows up 2 GB. The ultimate command is

sed 's/utf8mb4_unicode_520_ci/utf8_unicode_ci/g' original-mysql-data.sql > updated-mysql-data.sql
sed 's/utf8mb4/utf8/g' original-mysql-data.sql > updated-mysql-data.sql

Done!

Scale the contents of a div by a percentage?

This cross-browser lib seems safer - just zoom and moz-transform won't cover as many browsers as jquery.transform2d's scale().

http://louisremi.github.io/jquery.transform.js/

For example

$('#div').css({ transform: 'scale(.5)' });

Update

OK - I see people are voting this down without an explanation. The other answer here won't work in old Safari (people running Tiger), and it won't work consistently in some older browsers - that is, it does scale things but it does so in a way that's either very pixellated or shifts the position of the element in a way that doesn't match other browsers.

http://www.browsersupport.net/CSS/zoom

Or just look at this question, which this one is likely just a dupe of:

complete styles for cross browser CSS zoom

How to make JQuery-AJAX request synchronous

Can you try this,

var ajaxSubmit = function(formE1) {

            var password = $.trim($('#employee_password').val());

             $.ajax({
                type: "POST",
                async: "false",
                url: "checkpass.php",
                data: "password="+password,
                success: function(html) {
                    var arr=$.parseJSON(html);
                    if(arr == "Successful")
                    { 
                         **$("form[name='form']").submit();**
                        return true;
                    }
                    else
                    {    return false;
                    }
                }
            });
              **return false;**
        }

Difference between logical addresses, and physical addresses?

  1. An address generated by the CPU is commonly referred to as a logical address. The set of all logical addresses generated by a program is known as logical address space. Whereas, an address seen by the memory unit- that is, the one loaded into the memory-address register of the memory- is commonly referred to as physical address. The set of all physical addresses corresponding to the logical addresses is known as physical address space.
  2. The compile-time and load-time address-binding methods generate identical logical and physical addresses. However, in the execution-time address-binding scheme, the logical and physical-address spaces differ.
  3. The user program never sees the physical addresses. The program creates a pointer to a logical address, say 346, stores it in memory, manipulate it, compares it to other logical addresses- all as the number 346. Only when a logical address is used as memory address, it is relocated relative to the base/relocation register. The memory-mapping hardware device called the memory- management unit(MMU) converts logical addresses into physical addresses.
  4. Logical addresses range from 0 to max. User program that generates logical address thinks that the process runs in locations 0 to max. Logical addresses must be mapped to physical addresses before they are used. Physical addresses range from (R+0) to (R + max) for a base/relocation register value R.
  5. Example: enter image description here Mapping from logical to physical addresses using memory management unit (MMU) and relocation/base register The value in relocation/base register is added to every logical address generated by a user process, at the time it is sent to memory, to generate corresponding physical address. In the above figure, base/ relocation value is 14000, then an attempt by the user to access the location 346 is mapped to 14346.

The way to check a HDFS directory's size?

With this you will get size in GB

hdfs dfs -du PATHTODIRECTORY | awk '/^[0-9]+/ { print int($1/(1024**3)) " [GB]\t" $2 }'

lexical or preprocessor issue file not found occurs while archiving?

I had this problem after changed project name. I used all the methods mentioned on the internet but still doesn't work. Then I realized that all the header files not found was from cocoapods, so I re-installed the cocoapods using pod install, and thus solved the problem.

Hope this could help.

How to remove a key from Hash and get the remaining hash in Ruby/Rails?

There are many ways to remove a key from a hash and get the remaining hash in Ruby.

  1. .slice => It will return selected keys and not delete them from the original hash. Use slice! if you want to remove the keys permanently else use simple slice.

    2.2.2 :074 > hash = {"one"=>1, "two"=>2, "three"=>3}
     => {"one"=>1, "two"=>2, "three"=>3} 
    2.2.2 :075 > hash.slice("one","two")
     => {"one"=>1, "two"=>2} 
    2.2.2 :076 > hash
     => {"one"=>1, "two"=>2, "three"=>3} 
    
  2. .delete => It will delete the selected keys from the original hash(it can accept only one key and not more than one).

    2.2.2 :094 > hash = {"one"=>1, "two"=>2, "three"=>3}
     => {"one"=>1, "two"=>2, "three"=>3} 
    2.2.2 :095 > hash.delete("one")
     => 1 
    2.2.2 :096 > hash
     => {"two"=>2, "three"=>3} 
    
  3. .except => It will return the remaining keys but not delete anything from the original hash. Use except! if you want to remove the keys permanently else use simple except.

    2.2.2 :097 > hash = {"one"=>1, "two"=>2, "three"=>3}
     => {"one"=>1, "two"=>2, "three"=>3} 
    2.2.2 :098 > hash.except("one","two")
     => {"three"=>3} 
    2.2.2 :099 > hash
     => {"one"=>1, "two"=>2, "three"=>3}         
    
  4. .delete_if => In case you need to remove a key based on a value. It will obviously remove the matching keys from the original hash.

    2.2.2 :115 > hash = {"one"=>1, "two"=>2, "three"=>3, "one_again"=>1}
     => {"one"=>1, "two"=>2, "three"=>3, "one_again"=>1} 
    2.2.2 :116 > value = 1
     => 1 
    2.2.2 :117 > hash.delete_if { |k,v| v == value }
     => {"two"=>2, "three"=>3} 
    2.2.2 :118 > hash
     => {"two"=>2, "three"=>3} 
    
  5. .compact => It is used to remove all nil values from the hash. Use compact! if you want to remove the nil values permanently else use simple compact.

    2.2.2 :119 > hash = {"one"=>1, "two"=>2, "three"=>3, "nothing"=>nil, "no_value"=>nil}
     => {"one"=>1, "two"=>2, "three"=>3, "nothing"=>nil, "no_value"=>nil} 
    2.2.2 :120 > hash.compact
     => {"one"=>1, "two"=>2, "three"=>3}
    

Results based on Ruby 2.2.2.

How do I get the last day of a month?

To get last day of a month in a specific calendar - and in an extension method -:

public static int DaysInMonthBy(this DateTime src, Calendar calendar)
{
    var year = calendar.GetYear(src);                   // year of src in your calendar
    var month = calendar.GetMonth(src);                 // month of src in your calendar
    var lastDay = calendar.GetDaysInMonth(year, month); // days in month means last day of that month in your calendar
    return lastDay;
}

List all files and directories in a directory + subdirectories

A littlebit simple and slowly but working!! if you do not give a filepath basicly use the "fixPath" this is just example.... you can search the correct fileType what you want, i did a mistake when i chosen the list name because the "temporaryFileList is the searched file list so carry on that.... and the "errorList" is speaks for itself

 static public void Search(string path, string fileType, List<string> temporaryFileList, List<string> errorList)
    {

        List<string> temporaryDirectories = new List<string>();

        //string fix = @"C:\Users\" + Environment.UserName + @"\";
        string fix = @"C:\";
        string folders = "";
        //Alap útvonal megadása 
        if (path.Length != 0)
        { folders = path; }
        else { path = fix; }

        int j = 0;
        int equals = 0;
        bool end = true;

        do
        {

            equals = j;
            int k = 0;

            try
            {

                int foldersNumber = 
                Directory.GetDirectories(folders).Count();
                int fileNumber = Directory.GetFiles(folders).Count();

                if ((foldersNumber != 0 || fileNumber != 0) && equals == j)
                {

                    for (int i = k; k < 
                    Directory.GetDirectories(folders).Length;)
                    {

             temporaryDirectories.Add(Directory.GetDirectories(folders)[k]);
                        k++;
                    }

                    if (temporaryDirectories.Count == j)
                    {
                        end = false;
                        break;
                    }
                    foreach (string files in Directory.GetFiles(folders))
                    {
                        if (files != string.Empty)
                        {
                            if (fileType.Length == 0)
                            {
                                temporaryDirectories.Add(files);
                            }
                            else
                            {

                                if (files.Contains(fileType))
                                {
                                    temporaryDirectories.Add(files);

                                }
                            }
                        }
                        else
                        {
                            break;
                        }
                    }

                }

                equals++;

                for (int i = j; i < temporaryDirectories.Count;)
                {
                    folders = temporaryDirectories[i];
                    j++;
                    break;
                }

            }
            catch (Exception ex)
            {
                errorList.Add(folders);

                for (int i = j; i < temporaryDirectories.Count;)
                {
                    folders = temporaryDirectories[i];
                    j++;
                    break;
                }
            }
        } while (end);
    }

A reference to the dll could not be added

I had this issue after my PC has been restarted during building the solution. My two references gone, so I had to rebuild my two projects manually and then I could add references without error.

How to set environment variables in Python?

if i do os.environ["DEBUSSY"] = 1, it complains saying that 1 has to be string.

Then do

os.environ["DEBUSSY"] = "1"

I also want to know how to read the environment variables in python(in the later part of the script) once i set it.

Just use os.environ["DEBUSSY"], as in

some_value = os.environ["DEBUSSY"]

Can an XSLT insert the current date?

For MSXML parser, try this:

<xsl:stylesheet version="1.0"
                xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
                xmlns:msxsl="urn:schemas-microsoft-com:xslt"
                xmlns:my="urn:sample" extension-element-prefixes="msxml">

    <msxsl:script language="JScript" implements-prefix="my">
       function today()
       {
          return new Date(); 
       } 
    </msxsl:script> 
    <xsl:template match="/">

        Today = <xsl:value-of select="my:today()"/>

    </xsl:template> 
</xsl:stylesheet>

Also read XSLT Stylesheet Scripting using msxsl:script and Extending XSLT with JScript, C#, and Visual Basic .NET