Programs & Examples On #Yui compressor

YUI Compressor is a utility that can minify/compress JavaScript and/or Cascading Style Sheets to reduce the file payload size for web pages. Available in Java and .NET.

In plain English, what does "git reset" do?

Remember that in git you have:

  • the HEAD pointer, which tells you what commit you're working on
  • the working tree, which represents the state of the files on your system
  • the staging area (also called the index), which "stages" changes so that they can later be committed together

Please include detailed explanations about:

--hard, --soft and --merge;

In increasing order of dangerous-ness:

  • --soft moves HEAD but doesn't touch the staging area or the working tree.
  • --mixed moves HEAD and updates the staging area, but not the working tree.
  • --merge moves HEAD, resets the staging area, and tries to move all the changes in your working tree into the new working tree.
  • --hard moves HEAD and adjusts your staging area and working tree to the new HEAD, throwing away everything.

concrete use cases and workflows;

  • Use --soft when you want to move to another commit and patch things up without "losing your place". It's pretty rare that you need this.

--

# git reset --soft example
touch foo                            // Add a file, make some changes.
git add foo                          // 
git commit -m "bad commit message"   // Commit... D'oh, that was a mistake!
git reset --soft HEAD^               // Go back one commit and fix things.
git commit -m "good commit"          // There, now it's right.

--

  • Use --mixed (which is the default) when you want to see what things look like at another commit, but you don't want to lose any changes you already have.

  • Use --merge when you want to move to a new spot but incorporate the changes you already have into that the working tree.

  • Use --hard to wipe everything out and start a fresh slate at the new commit.

Data at the root level is invalid

I found that the example I was using had an xml document specification on the first line. I was using a stylesheet I got at this blog entry and the first line was

<?xmlversion="1.0"encoding="utf-8"?>

which was causing the error. When I removed that line, so that the stylesheet started with the line

<xsl:stylesheet version="1.0" xmlns:DTS="www.microsoft.com/SqlServer/Dts" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">

my transform worked. By the way, that blog post was the first good, easy-to follow example I have found for trying to get information from the XML definition of an SSIS package, but I did have to modify the paths in the example for my SSIS 2008 packages, so you might too. I also created a version to extract the "flow" from the precedence constraints. My final one looks like this:

    <xsl:stylesheet version="1.0" xmlns:DTS="www.microsoft.com/SqlServer/Dts" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
    <xsl:output method="text" encoding="utf-8" />
    <xsl:template match="/">
    <xsl:text>From,To~</xsl:text>
    <xsl:text>
</xsl:text>
    <xsl:for-each select="//DTS:PrecedenceConstraints/DTS:PrecedenceConstraint">
      <xsl:value-of select="@DTS:From"/>
      <xsl:text>,</xsl:text>
      <xsl:value-of select="@DTS:To"/>
       <xsl:text>~</xsl:text>
      <xsl:text>
</xsl:text>
    </xsl:for-each>
    </xsl:template>
</xsl:stylesheet>

and gave me a CSV with the tilde as my line delimiter. I replaced that with a line feed in my text editor then imported into excel to get a with look at the data flow in the package.

How to declare a variable in a template in Angular

Update

We can just create directive like *ngIf and call it *ngVar

ng-var.directive.ts

@Directive({
    selector: '[ngVar]',
})
export class VarDirective {
  @Input()
  set ngVar(context: any) {
    this.context.$implicit = this.context.ngVar = context;
    this.updateView();
  }

  context: any = {};

  constructor(private vcRef: ViewContainerRef, private templateRef: TemplateRef<any>) {}

  updateView() {
    this.vcRef.clear();
    this.vcRef.createEmbeddedView(this.templateRef, this.context);
  }
}

with this *ngVar directive we can use the following

<div *ngVar="false as variable">
      <span>{{variable | json}}</span>
</div>

or

<div *ngVar="false; let variable">
    <span>{{variable | json}}</span>
</div>

or

<div *ngVar="45 as variable">
    <span>{{variable | json}}</span>
</div>

or

<div *ngVar="{ x: 4 } as variable">
    <span>{{variable | json}}</span>
</div>

Plunker Example Angular4 ngVar

See also

Original answer

Angular v4

1) div + ngIf + let

<div *ngIf="{ a: 1, b: 2 }; let variable">
  <span>{{variable.a}}</span>
  <span>{{variable.b}}</span>
</div>

2) div + ngIf + as

view

<div *ngIf="{ a: 1, b: 2, c: 3 + x } as variable">
  <span>{{variable.a}}</span>
  <span>{{variable.b}}</span>
  <span>{{variable.c}}</span>
</div>

component.ts

export class AppComponent {
  x = 5;
}

3) If you don't want to create wrapper like div you can use ng-container

view

<ng-container *ngIf="{ a: 1, b: 2, c: 3 + x } as variable">
  <span>{{variable.a}}</span>
  <span>{{variable.b}}</span>
  <span>{{variable.c}}</span>
</ng-container>

As @Keith mentioned in comments

this will work in most cases but it is not a general solution since it relies on variable being truthy

See update for another approach.

Reading tab-delimited file with Pandas - works on Windows, but not on Mac

Another option would be to add engine='python' to the command pandas.read_csv(filename, sep='\t', engine='python')

Java substring: 'string index out of range'

if (itemdescription != null && itemdescription.length() > 0) {
    pstmt2.setString(3, itemdescription.substring(0, Math.min(itemdescription.length(), 38))); 
} else { 
    pstmt2.setString(3, "_"); 
}

Difference between JSONObject and JSONArray

I always use object, it is more easily extendable, JSON array is not. For example you originally had some data as a json array, then you needed to add a status header on it you'd be a bit stuck, unless you'd nested the data in an object. The only disadvantage is a slight increase in complexity of creation / parsing.

So instead of

[datum0, datum1, datumN]

You'd have

{data: [datum0, datum1, datumN]}

then later you can add more...

{status: "foo", data: [datum0, datum1, datumN]}

How to pip install a package with min and max version range?

An elegant method would be to use the ~= compatible release operator according to PEP 440. In your case this would amount to:

package~=0.5.0

As an example, if the following versions exist, it would choose 0.5.9:

  • 0.5.0
  • 0.5.9
  • 0.6.0

For clarification, each pair is equivalent:

~= 0.5.0
>= 0.5.0, == 0.5.*

~= 0.5
>= 0.5, == 0.*

MySQL : ERROR 1215 (HY000): Cannot add foreign key constraint

Even if this is not directly linked precisely to your situation, it may help further readers to note that you can get exactly the same error output when you type show engine innodb mstatus if you do not respect the order of creating the database tables; meaning you must not add a foreign constraint referencing a table that does not exist yet. The reference table must exist prior to the table which points to it.

This is also true when the table creation order is respected but not the columns involved in the foreign key constraint.

Creating table variable in SQL server 2008 R2

@tableName Table variables are alive for duration of the script running only i.e. they are only session level objects.

To test this, open two query editor windows under sql server management studio, and create table variables with same name but different structures. You will get an idea. The @tableName object is thus temporary and used for our internal processing of data, and it doesn't contribute to the actual database structure.

There is another type of table object which can be created for temporary use. They are #tableName objects declared like similar create statement for physical tables:

Create table #test (Id int, Name varchar(50))

This table object is created and stored in temp database. Unlike the first one, this object is more useful, can store large data and takes part in transactions etc. These tables are alive till the connection is open. You have to drop the created object by following script before re-creating it.

IF OBJECT_ID('tempdb..#test') IS NOT NULL
  DROP TABLE #test 

Hope this makes sense !

DateTime format to SQL format using C#

Let's use the built in SqlDateTime class

new SqlDateTime(DateTime.Now).ToSqlString()

But still need to check for null values. This will throw overflow exception

new SqlDateTime(DateTime.MinValue).ToSqlString()

SqlDateTime overflow. Must be between 1/1/1753 12:00:00 AM and 12/31/9999 11:59:59 PM.

Difference between variable declaration syntaxes in Javascript (including global variables)?

Keeping it simple :

a = 0

The code above gives a global scope variable

var a = 0;

This code will give a variable to be used in the current scope, and under it

window.a = 0;

This generally is same as the global variable.

How to store and retrieve a dictionary with redis

As the basic answer has already give by other people, I would like to add some to it.

Following are the commands in REDIS to perform basic operations with HashMap/Dictionary/Mapping type values.

  1. HGET => Returns value for single key passed
  2. HSET => set/updates value for the single key
  3. HMGET => Returns value for single/multiple keys passed
  4. HMSET => set/updates values for the multiple key
  5. HGETALL => Returns all the (key, value) pairs in the mapping.

Following are their respective methods in redis-py library :-

  1. HGET => hget
  2. HSET => hset
  3. HMGET => hmget
  4. HMSET => hmset
  5. HGETALL => hgetall

All of the above setter methods creates the mapping, if it doesn't exists. All of the above getter methods doesn't raise error/exceptions, if mapping/key in mapping doesn't exists.

Example:
=======
In [98]: import redis
In [99]: conn = redis.Redis('localhost')

In [100]: user = {"Name":"Pradeep", "Company":"SCTL", "Address":"Mumbai", "Location":"RCP"}

In [101]: con.hmset("pythonDict", {"Location": "Ahmedabad"})
Out[101]: True

In [102]: con.hgetall("pythonDict")
Out[102]:
{b'Address': b'Mumbai',
 b'Company': b'SCTL',
 b'Last Name': b'Rajpurohit',
 b'Location': b'Ahmedabad',
 b'Name': b'Mangu Singh'}

In [103]: con.hmset("pythonDict", {"Location": "Ahmedabad", "Company": ["A/C Pri
     ...: sm", "ECW", "Musikaar"]})
Out[103]: True

In [104]: con.hgetall("pythonDict")
Out[104]:
{b'Address': b'Mumbai',
 b'Company': b"['A/C Prism', 'ECW', 'Musikaar']",
 b'Last Name': b'Rajpurohit',
 b'Location': b'Ahmedabad',
 b'Name': b'Mangu Singh'}

In [105]: con.hget("pythonDict", "Name")
Out[105]: b'Mangu Singh'

In [106]: con.hmget("pythonDict", "Name", "Location")
Out[106]: [b'Mangu Singh', b'Ahmedabad']

I hope, it makes things more clear.

How to create global variables accessible in all views using Express / Node.JS?

With the differents answers, I implemented this code to use an external file JSON loaded in "app.locals"

Parameters

{
    "web": {
        "title" : "Le titre de ma Page",
        "cssFile" : "20200608_1018.css"
    }
}

Application

var express     = require('express');
var appli       = express();
var serveur     = require('http').Server(appli);

var myParams    = require('./include/my_params.json');
var myFonctions = require('./include/my_fonctions.js');

appli.locals = myParams;

EJS Page

<!DOCTYPE html>
<html lang="fr">
<head>
    <meta charset="UTF-8">
    <title><%= web.title %></title>
    <link rel="stylesheet" type="text/css" href="/css/<%= web.cssFile %>">
</head>

</body>
</html>

Hoping it will help

Unmarshaling nested JSON objects

Assign the values of nested json to struct until you know the underlying type of json keys:-

package main

import (
    "encoding/json"
    "fmt"
)

// Object
type Object struct {
    Foo map[string]map[string]string `json:"foo"`
    More string `json:"more"`
}

func main(){
    someJSONString := []byte(`{"foo":{ "bar": "1", "baz": "2" }, "more": "text"}`)
    var obj Object
    err := json.Unmarshal(someJSONString, &obj)
    if err != nil{
        fmt.Println(err)
    }
    fmt.Println("jsonObj", obj)
}

How to simulate a touch event in Android?

When using Monkey Script I noticed that DispatchPress(KEYCODE_BACK) is doing nothing which really suck. In many cases this is due to the fact that the Activity doesn't consume the Key event. The solution to this problem is to use a mix of monkey script and adb shell input command in a sequence.

1 Using monkey script gave some great timing control. Wait a certain amount of second for the activity and is a blocking adb call.
2 Finally sending adb shell input keyevent 4 will end the running APK.

EG

adb shell monkey -p com.my.application -v -v -v -f /sdcard/monkey_script.txt 1
adb shell input keyevent 4

grep exclude multiple strings

Two examples of filtering out multiple lines with grep:

Put this in filename.txt:

abc
def
ghi
jkl

grep command using -E option with a pipe between tokens in a string:

grep -Ev 'def|jkl' filename.txt

prints:

abc
ghi

Command using -v option with pipe between tokens surrounded by parens:

egrep -v '(def|jkl)' filename.txt

prints:

abc
ghi

Use .htaccess to redirect HTTP to HTTPs

Here is an alternative solution you can use if you don't want to edit .htaccess:

add_action( 'template_redirect', 'nonhttps_template_redirect', 1 );

function nonhttps_template_redirect() {

    if ( is_ssl() ) {

        if ( 0 === strpos( $_SERVER['REQUEST_URI'], 'https' ) ) {

            wp_redirect( preg_replace( '|^http://|', 'https://', $_SERVER['REQUEST_URI'] ), 301 );

            exit();

        } else {

            wp_redirect( 'https://' . $_SERVER['HTTP_HOST'] . $_SERVER['REQUEST_URI'], 301 );

            exit();

        }

    }

}

You can place this at the bottom of your theme functions.php

Get GPS location via a service in Android

All these answers doesn't work from M - to - Android"O" - 8, Due to Dozer mode that restrict the service - whatever service or any background operation that requires discrete things in background would be no longer able to run.

So the approach would be listening to the system FusedLocationApiClient through BroadCastReciever that always listening the location and work even in Doze mode.

Posting the link would be pointless, please search FusedLocation with Broadcast receiver.

Thanks

how can I connect to a remote mongo server from Mac OS terminal

With Mongo 3.2 and higher just use your connection string as is:

mongo mongodb://username:[email protected]:10011/my_database

Can we have multiple <tbody> in same <table>?

Martin Joiner's problem is caused by a misunderstanding of the <caption> tag.

The <caption> tag defines a table caption.

The <caption> tag must be the first child of the <table> tag.

You can specify only one caption per table.

Also, note that the scope attribute should be placed on a <th> element and not on a <tr> element.

The proper way to write a multi-header multi-tbody table would be something like this :

_x000D_
_x000D_
<table id="dinner_table">_x000D_
    <caption>This is the only correct place to put a caption.</caption>_x000D_
    <tbody>_x000D_
        <tr class="header">_x000D_
            <th colspan="2" scope="col">First Half of Table (British Dinner)</th>_x000D_
        </tr>_x000D_
        <tr>_x000D_
            <th scope="row">1</th>_x000D_
            <td>Fish</td>_x000D_
        </tr>_x000D_
        <tr>_x000D_
            <th scope="row">2</th>_x000D_
            <td>Chips</td>_x000D_
        </tr>_x000D_
        <tr>_x000D_
            <th scope="row">3</th>_x000D_
            <td>Peas</td>_x000D_
        </tr>_x000D_
        <tr>_x000D_
            <th scope="row">4</th>_x000D_
            <td>Gravy</td>_x000D_
        </tr>_x000D_
    </tbody>_x000D_
    <tbody>_x000D_
        <tr class="header">_x000D_
            <th colspan="2" scope="col">Second Half of Table (Italian Dinner)</th>_x000D_
        </tr>_x000D_
        <tr>_x000D_
            <th scope="row">5</th>_x000D_
            <td>Pizza</td>_x000D_
        </tr>_x000D_
        <tr>_x000D_
            <th scope="row">6</th>_x000D_
            <td>Salad</td>_x000D_
        </tr>_x000D_
        <tr>_x000D_
            <th scope="row">7</th>_x000D_
            <td>Oil</td>_x000D_
        </tr>_x000D_
        <tr>_x000D_
            <th scope="row">8</th>_x000D_
            <td>Bread</td>_x000D_
        </tr>_x000D_
    </tbody>_x000D_
</table>
_x000D_
_x000D_
_x000D_

How to print multiple variable lines in Java

You can do it with 1 printf:

System.out.printf("First Name: %s\nLast Name: %s",firstname, lastname);

Using the "With Clause" SQL Server 2008

Just a poke, but here's another way to write FizzBuzz :) 100 rows is enough to show the WITH statement, I reckon.

;WITH t100 AS (
 SELECT n=number
 FROM master..spt_values
 WHERE type='P' and number between 1 and 100
)                
 SELECT
    ISNULL(NULLIF(
    CASE WHEN n % 3 = 0 THEN 'Fizz' Else '' END +
    CASE WHEN n % 5 = 0 THEN 'Buzz' Else '' END, ''), RIGHT(n,3))
 FROM t100

But the real power behind WITH (known as Common Table Expression http://msdn.microsoft.com/en-us/library/ms190766.aspx "CTE") in SQL Server 2005 and above is the Recursion, as below where the table is built up through iterations adding to the virtual-table each time.

;WITH t100 AS (
 SELECT n=1
 union all
 SELECT n+1
 FROM t100
 WHERE n < 100
)                
 SELECT
    ISNULL(NULLIF(
    CASE WHEN n % 3 = 0 THEN 'Fizz' Else '' END +
    CASE WHEN n % 5 = 0 THEN 'Buzz' Else '' END, ''), RIGHT(n,3))
 FROM t100

To run a similar query in all database, you can use the undocumented sp_msforeachdb. It has been mentioned in another answer, but it is sp_msforeachdb, not sp_foreachdb.

Be careful when using it though, as some things are not what you expect. Consider this example

exec sp_msforeachdb 'select count(*) from sys.objects'

Instead of the counts of objects within each DB, you will get the SAME count reported, begin that of the current DB. To get around this, always "use" the database first. Note the square brackets to qualify multi-word database names.

exec sp_msforeachdb 'use [?]; select count(*) from sys.objects'

For your specific query about populating a tally table, you can use something like the below. Not sure about the DATE column, so this tally table has only the DBNAME and IMG_COUNT columns, but hope it helps you.

create table #tbl (dbname sysname, img_count int);

exec sp_msforeachdb '
use [?];
if object_id(''tbldoc'') is not null
insert #tbl
select ''?'', count(*) from tbldoc'

select * from #tbl

Fastest way of finding differences between two files in unix?

You could try..

comm -13 <(sort file1) <(sort file2) > file3

or

grep -Fxvf file1 file2 > file3

or

diff file1 file2 | grep "<" | sed 's/^<//g'  > file3

or

join -v 2 <(sort file1) <(sort file2) > file3

MySQL Error 1215: Cannot add foreign key constraint

I just wanted to add this case as well for VARCHAR foreign key relation. I spent the last week trying to figure this out in MySQL Workbench 8.0 and was finally able to fix the error.

Short Answer: The character set and collation of the schema, the table, the column, the referencing table, the referencing column and any other tables that reference to the parent table have to match.

Long Answer: I had an ENUM datatype in my table. I changed this to VARCHAR and I can get the values from a reference table so that I don't have to alter the parent table to add additional options. This foreign-key relationship seemed straightforward but I got 1215 error. arvind's answer and the following link suggested the use of

SHOW ENGINE INNODB STATUS;

On using this command I got the following verbose description for the error with no additional helpful information

Cannot find an index in the referenced table where the referenced columns appear as the first columns, or column types in the table and the referenced table do not match for constraint. Note that the internal storage type of ENUM and SET changed in tables created with >= InnoDB-4.1.12, and such columns in old tables cannot be referenced by such columns in new tables. Please refer to http://dev.mysql.com/doc/refman/8.0/en/innodb-foreign-key-constraints.html for correct foreign key definition.

After which I used SET FOREIGN_KEY_CHECKS=0; as suggested by Arvind Bharadwaj and the link here:

This gave the following error message:

Error Code: 1822. Failed to add the foreign key constraint. Missing index for constraint

At this point, I 'reverse engineer'-ed the schema and I was able to make the foreign-key relationship in the EER diagram. On 'forward engineer'-ing, I got the following error:

Error 1452: Cannot add or update a child row: a foreign key constraint fails

When I 'forward engineer'-ed the EER diagram to a new schema, the SQL script ran without issues. On comparing the generated SQL from the attempts to forward engineer, I found that the difference was the character set and collation. The parent table, child table and the two columns had utf8mb4 character set and utf8mb4_0900_ai_ci collation, however, another column in the parent table was referenced using CHARACTER SET = utf8 , COLLATE = utf8_bin ; to a different child table.

For the entire schema, I changed the character set and collation for all the tables and all the columns to the following:

CHARACTER SET = utf8mb4 COLLATE = utf8mb4_general_ci;

This finally solved my problem with 1215 error.

Side Note: The collation utf8mb4_general_ci works in MySQL Workbench 5.0 or later. Collation utf8mb4_0900_ai_ci works just for MySQL Workbench 8.0 or higher. I believe one of the reasons I had issues with character set and collation is due to MySQL Workbench upgrade to 8.0 in between. Here is a link that talks more about this collation.

MySQL JOIN with LIMIT 1 on joined table

SELECT c.id, c.title, p.id AS product_id, p.title
FROM categories AS c
JOIN products AS p ON c.id = p.category_id
GROUP BY c.id

This will return the first data in products (equals limit 1)

Detect if the device is iPhone X

I am trying to make work the previous replies and none of them worked for me. So I found one solution for SwiftUI. Creating a file called UIDevice+Notch.swift

And its content:

extension UIDevice {
    var hasNotch: Bool {
        let bottom = UIApplication.shared.keyWindow?.safeAreaInsets.bottom ?? 0
        return bottom > 0
    }
}

Usage:

if UIDevice.current.hasNotch {
    //... consider notch 
} else {
    //... don't have to consider notch 
}

Parse JSON file using GSON

One thing that to be remembered while solving such problems is that in JSON file, a { indicates a JSONObject and a [ indicates JSONArray. If one could manage them properly, it would be very easy to accomplish the task of parsing the JSON file. The above code was really very helpful for me and I hope this content adds some meaning to the above code.

The Gson JsonReader documentation explains how to handle parsing of JsonObjects and JsonArrays:

  • Within array handling methods, first call beginArray() to consume the array's opening bracket. Then create a while loop that accumulates values, terminating when hasNext() is false. Finally, read the array's closing bracket by calling endArray().
  • Within object handling methods, first call beginObject() to consume the object's opening brace. Then create a while loop that assigns values to local variables based on their name. This loop should terminate when hasNext() is false. Finally, read the object's closing brace by calling endObject().

Identify duplicate values in a list in Python

You can use list compression and set to reduce the complexity.

my_list = [3, 5, 2, 1, 4, 4, 1]
opt = [item for item in set(my_list) if my_list.count(item) > 1]

Is there any good dynamic SQL builder library in Java?

ddlutils is my best choice:http://db.apache.org/ddlutils/api/org/apache/ddlutils/platform/SqlBuilder.html

here is create example(groovy):

Platform platform  = PlatformFactory.createNewPlatformInstance("oracle");//db2,...
//create schema    
def db =        new Database();
def t = new Table(name:"t1",description:"XXX");
def col1 = new Column(primaryKey:true,name:"id",type:"bigint",required:true);
t.addColumn(col1);
t.addColumn(new Column(name:"c2",type:"DECIMAL",size:"8,2"));
t.addColumn( new Column(name:"c3",type:"varchar"));
t.addColumn(new Column(name:"c4",type:"TIMESTAMP",description:"date"));        
db.addTable(t);
println platform.getCreateModelSql(db, false, false)

//you can read Table Object from  platform.readModelFromDatabase(....)
def sqlbuilder = platform.getSqlBuilder();
println "insert:"+sqlbuilder.getInsertSql(t,["id":1,c2:3],false);
println "update:"+sqlbuilder.getUpdateSql(t,["id":1,c2:3],false);
println "delete:"+sqlbuilder.getDeleteSql(t,["id":1,c2:3],false);
//http://db.apache.org/ddlutils/database-support.html

How do I change the background color of the ActionBar of an ActionBarActivity using XML?

When you are Extending Activity use following Code

ActionBar actionbar = getActionBar();
actionbar.setBackgroundDrawable(new ColorDrawable("color"));

When you are Extending AppCompatActivity use following Code

ActionBar actionbar = getSupportActionBar();
actionbar.setBackgroundDrawable(new ColorDrawable("color"));

How to succinctly write a formula with many variables from a data frame?

An extension of juba's method is to use reformulate, a function which is explicitly designed for such a task.

## Create a formula for a model with a large number of variables:
xnam <- paste("x", 1:25, sep="")

reformulate(xnam, "y")
y ~ x1 + x2 + x3 + x4 + x5 + x6 + x7 + x8 + x9 + x10 + x11 + 
    x12 + x13 + x14 + x15 + x16 + x17 + x18 + x19 + x20 + x21 + 
    x22 + x23 + x24 + x25

For the example in the OP, the easiest solution here would be

# add y variable to data.frame d
d <- cbind(y, d)
reformulate(names(d)[-1], names(d[1]))
y ~ x1 + x2 + x3

or

mod <- lm(reformulate(names(d)[-1], names(d[1])), data=d)

Note that adding the dependent variable to the data.frame in d <- cbind(y, d) is preferred not only because it allows for the use of reformulate, but also because it allows for future use of the lm object in functions like predict.

history.replaceState() example?

Suppose https://www.mozilla.org/foo.html executes the following JavaScript:

const stateObj = { foo: 'bar' };

history.pushState(stateObj, '', 'bar.html');

This will cause the URL bar to display https://www.mozilla.org/bar2.html, but won't cause the browser to load bar2.html or even check that bar2.html exists.

Max or Default?

litt late, but I had the same concern...

Rephrasing your code from the original post, you want the max of the set S defined by

(From y In context.MyTable _
 Where y.MyField = value _
 Select y.MyCounter)

Taking in account your last comment

Suffice to say that I know I want 0 when there are no records to select from, which definitely has an impact on the eventual solution

I can rephrase your problem as: You want the max of {0 + S}. And it looks like the proposed solution with concat is semantically the right one :-)

var max = new[]{0}
          .Concat((From y In context.MyTable _
                   Where y.MyField = value _
                   Select y.MyCounter))
          .Max();

Why can't I center with margin: 0 auto?

Why not?

#header {
    text-align: center;
}

#header ul {
    display: inline;
}

How can I get a specific field of a csv file?

#!/usr/bin/env python
"""Print a field specified by row, column numbers from given csv file.

USAGE:
    %prog csv_filename row_number column_number
"""
import csv
import sys

filename = sys.argv[1]
row_number, column_number = [int(arg, 10)-1 for arg in sys.argv[2:])]

with open(filename, 'rb') as f:
     rows = list(csv.reader(f))
     print rows[row_number][column_number]

Example

$ python print-csv-field.py input.csv 2 2
ddddd

Note: list(csv.reader(f)) loads the whole file in memory. To avoid that you could use itertools:

import itertools
# ...
with open(filename, 'rb') as f:
     row = next(itertools.islice(csv.reader(f), row_number, row_number+1))
     print row[column_number]

A CORS POST request works from plain JavaScript, but why not with jQuery?

UPDATE: As TimK pointed out, this isn't needed with jquery 1.5.2 any more. But if you want to add custom headers or allow the use of credentials (username, password, or cookies, etc), read on.


I think I found the answer! (4 hours and a lot of cursing later)

//This does not work!!
Access-Control-Allow-Headers: *

You need to manually specify all the headers you will accept (at least that was the case for me in FF 4.0 & Chrome 10.0.648.204).

jQuery's $.ajax method sends the "x-requested-with" header for all cross domain requests (i think its only cross domain).

So the missing header needed to respond to the OPTIONS request is:

//no longer needed as of jquery 1.5.2
Access-Control-Allow-Headers: x-requested-with

If you are passing any non "simple" headers, you will need to include them in your list (i send one more):

//only need part of this for my custom header
Access-Control-Allow-Headers: x-requested-with, x-requested-by

So to put it all together, here is my PHP:

// * wont work in FF w/ Allow-Credentials
//if you dont need Allow-Credentials, * seems to work
header('Access-Control-Allow-Origin: http://www.example.com');
//if you need cookies or login etc
header('Access-Control-Allow-Credentials: true');
if ($this->getRequestMethod() == 'OPTIONS')
{
  header('Access-Control-Allow-Methods: GET, POST, PUT, DELETE, OPTIONS');
  header('Access-Control-Max-Age: 604800');
  //if you need special headers
  header('Access-Control-Allow-Headers: x-requested-with');
  exit(0);
}

jQuery multiple events to trigger the same function

You can use .on() to bind a function to multiple events:

$('#element').on('keyup keypress blur change', function(e) {
    // e.type is the type of event fired
});

Or just pass the function as the parameter to normal event functions:

var myFunction = function() {
   ...
}

$('#element')
    .keyup(myFunction)
    .keypress(myFunction)
    .blur(myFunction)
    .change(myFunction)

How to sort a HashMap in Java

Sorting HashMap by Value:

As others have pointed out. HashMaps are for easy lookups if you change that or try to sort inside the map itself you will no longer have O(1) lookup.

The code for your sorting is as follows:

class Obj implements Comparable<Obj>{
    String key;
    ArrayList<Integer> val;
    Obj(String key, ArrayList<Integer> val)
    {
    this.key=key;
    this.val=val;
    }
    public int compareTo(Obj o)
    {
     /* Write your sorting logic here. 
     this.val compared to o.val*/
     return 0;
    }
}

public void sortByValue(Map<String, ArrayList<>> mp){

    ArrayList<Obj> arr=new ArrayList<Obj>();
    for(String z:mp.keySet())//Make an object and store your map into the arrayList
    {

        Obj o=new Obj(z,mp.get(z));
        arr.add(o);
    }
    System.out.println(arr);//Unsorted
    Collections.sort(arr);// This sorts based on the conditions you coded in the compareTo function.
    System.out.println(arr);//Sorted
}

jQuery UI Dialog Box - does not open after being closed

I had the same problem with jquery-ui overlay dialog box - it would work only once and then stop unless i reload the page. I found the answer in one of their examples -
Multiple overlays on a same page
flowplayer_tools_multiple_open_close
- who would have though, right?? :-) -

the important setting appeared to be

oneInstance: false

so, now i have it like this -

$(document).ready(function() {

 var overlays = null;

 overlays = jQuery("a[rel]");

 for (var n = 0; n < overlays.length; n++) {

    $(overlays[n]).overlay({
        oneInstance: false, 
        mask: '#669966',
        effect: 'apple',
        onBeforeLoad: function() {
            overlay_before_load(this);
        }
    });

  }

}

and everything works just fine

hope this helps somebody

O.

What port is a given program using?

"netstat -natp" is what I always use.

Android: checkbox listener

You get the error because you imported wrong package.You should import android.widget.CompoundButton.OnCheckedChangeListener;

So the callback should be :

        box.setOnCheckedChangeListener(new OnCheckedChangeListener() {

        @Override
        public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
            // TODO Auto-generated method stub

        }
    });

How to read existing text files without defining path

You absolutely need to know where the files to be read can be located. However, this information can be relative of course so it may be well adapted to other systems.

So it could relate to the current directory (get it from Directory.GetCurrentDirectory()) or to the application executable path (eg. Application.ExecutablePath comes to mind if using Windows Forms or via Assembly.GetEntryAssembly().Location) or to some special Windows directory like "Documents and Settings" (you should use Environment.GetFolderPath() with one element of the Environment.SpecialFolder enumeration).

Note that the "current directory" and the path of the executable are not necessarily identical. You need to know where to look!

In either case, if you need to manipulate a path use the Path class to split or combine parts of the path.

Redirecting a request using servlets and the "setHeader" method not working

Alternatively, you could try the following,

resp.setStatus(301);
resp.setHeader("Location", "index.jsp");
resp.setHeader("Connection", "close");

Get Substring - everything before certain char

The LINQy way

String.Concat( "223232-1.jpg".TakeWhile(c => c != '-') )

(But, you do need to test for null ;)

Android WebView progress bar

For a horizontal progress bar, you first need to define your progress bar and link it with your XML file like this, in the onCreate:

final TextView txtview = (TextView)findViewById(R.id.tV1);
final ProgressBar pbar = (ProgressBar) findViewById(R.id.pB1);

Then, you may use onProgressChanged Method in your WebChromeClient:

MyView.setWebChromeClient(new WebChromeClient() {
            public void onProgressChanged(WebView view, int progress) {
               if(progress < 100 && pbar.getVisibility() == ProgressBar.GONE){
                   pbar.setVisibility(ProgressBar.VISIBLE);
                   txtview.setVisibility(View.VISIBLE);
               }

               pbar.setProgress(progress);
               if(progress == 100) {
                   pbar.setVisibility(ProgressBar.GONE);
                   txtview.setVisibility(View.GONE);
               }
            }
        });

After that, in your layout you have something like this

<TextView android:text="Loading, . . ." 
    android:textAppearance="?android:attr/textAppearanceSmall"
    android:id="@+id/tV1" android:layout_height="wrap_content"
    android:layout_width="wrap_content"
    android:textColor="#000000"></TextView>

<ProgressBar android:id="@+id/pB1"
    style="?android:attr/progressBarStyleHorizontal" android:layout_width="fill_parent"
    android:layout_height="wrap_content" android:layout_centerVertical="true"
    android:padding="2dip">
</ProgressBar>

This is how I did it in my app.

How to create a GUID/UUID in Python

This function is fully configurable and generates unique uid based on the format specified

eg:- [8, 4, 4, 4, 12] , this is the format mentioned and it will generate the following uuid

LxoYNyXe-7hbQ-caJt-DSdU-PDAht56cMEWi

 import random as r

 def generate_uuid():
        random_string = ''
        random_str_seq = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
        uuid_format = [8, 4, 4, 4, 12]
        for n in uuid_format:
            for i in range(0,n):
                random_string += str(random_str_seq[r.randint(0, len(random_str_seq) - 1)])
            if n != 12:
                random_string += '-'
        return random_string

Hibernate Error: org.hibernate.NonUniqueObjectException: a different object with the same identifier value was already associated with the session

Check if you forgot to put @GenerateValue for @Id column. I had same problem with many to many relationship between Movie and Genre. The program threw Hibernate Error: org.hibernate.NonUniqueObjectException: a different object with the same identifier value was already associated with the session error. I found out later that I just have to make sure you have @GenerateValue to the GenreId get method.

How to create directory automatically on SD card

With API 8 and greater, the location of the SD card has changed. @fiXedd's answer is good, but for safer code, you should use Environment.getExternalStorageState() to check if the media is available. Then you can use getExternalFilesDir() to navigate to the directory you want (assuming you're using API 8 or greater).

You can read more in the SDK documentation.

Python, how to check if a result set is empty?

I had issues with rowcount always returning -1 no matter what solution I tried.

I found the following a good replacement to check for a null result.

c.execute("SELECT * FROM users WHERE id=?", (id_num,))
row = c.fetchone()
if row == None:
   print("There are no results for this query")

ansible : how to pass multiple commands

Here is worker like this. \o/

- name: "Exec items"
  shell: "{{ item }}"
  with_items:
    - echo "hello"
    - echo "hello2"

Make div fill remaining space along the main axis in flexbox

Basically I was trying to get my code to have a middle section on a 'row' to auto-adjust to the content on both sides (in my case, a dotted line separator). Like @Michael_B suggested, the key is using display:flex on the row container and at least making sure your middle container on the row has a flex-grow value of at least 1 higher than the outer containers (if outer containers don't have any flex-grow properties applied, middle container only needs 1 for flex-grow).

Here's a pic of what I was trying to do and sample code for how I solved it.

enter image description here

_x000D_
_x000D_
.row {
  background: lightgray;
  height: 30px;
  width: 100%;
  display: flex;
  align-items:flex-end;
  margin-top:5px;
}
.left {
  background:lightblue;
}
.separator{
  flex-grow:1;
  border-bottom:dotted 2px black;
}
.right {
  background:coral;
}
_x000D_
<div class="row">
  <div class="left">Left</div>
  <div class="separator"></div>
  <div class="right">Right With Text</div>
</div>
<div class="row">
  <div class="left">Left With More Text</div>
  <div class="separator"></div>
  <div class="right">Right</div>
</div>
<div class="row">
  <div class="left">Left With Text</div>
  <div class="separator"></div>
  <div class="right">Right With More Text</div>
</div>
_x000D_
_x000D_
_x000D_

What is the problem with shadowing names defined in outer scopes?

It depends how long the function is. The longer the function, the greater the chance that someone modifying it in future will write data thinking that it means the global. In fact, it means the local, but because the function is so long, it's not obvious to them that there exists a local with that name.

For your example function, I think that shadowing the global is not bad at all.

GetType used in PowerShell, difference between variables

Select-Object creates a new psobject and copies the properties you requested to it. You can verify this with GetType():

PS > $a.GetType().fullname
System.DayOfWeek

PS > $b.GetType().fullname
System.Management.Automation.PSCustomObject

Find an item in List by LINQ?

You can use FirstOfDefault with the Where Linq extension to get a MessageAction class from the IEnumerable. Reme

var action = Message.Actions.Where(e => e.targetByName == className).FirstOrDefault();

where

List Actions { get; set; }

Best way to concatenate List of String objects?

If you are developing for Android, there is TextUtils.join provided by the SDK.

How to add a list item to an existing unordered list?

Instead of

$("#header ul li:last")

try

$("#header ul")

How to import JSON File into a TypeScript file?

Angular 10

You should now edit the tsconfig.app.json (notice the "app" in the name) file instead.

There you'll find the compilerOptions, and you simply add resolveJsonModule: true.

So, for example, the file in a brand new project should look like this:

/* To learn more about this file see: https://angular.io/config/tsconfig. */
{
  "extends": "./tsconfig.base.json",
  "compilerOptions": {
    "outDir": "./out-tsc/app",
    "types": [],
    "resolveJsonModule": true
  },
  "files": [
    "src/main.ts",
    "src/polyfills.ts"
  ],
  "include": [
    "src/**/*.d.ts"
  ]
}

Creating a selector from a method name with parameters

You can't pass a parameter in a @selector().

It looks like you're trying to implement a callback. The best way to do that would be something like this:

[object setCallbackObject:self withSelector:@selector(myMethod:)];

Then in your object's setCallbackObject:withSelector: method: you can call your callback method.

-(void)setCallbackObject:(id)anObject withSelector:(SEL)selector {
    [anObject performSelector:selector];
}

Copy files on Windows Command Line with Progress

The Esentutl /y option allows copyng (single) file files with progress bar like this :

enter image description here

the command should look like :

esentutl /y "FILE.EXT" /d "DEST.EXT" /o

The command is available on every windows machine but the y option is presented in windows vista. As it works only with single files does not look very useful for a small ones. Other limitation is that the command cannot overwrite files. Here's a wrapper script that checks the destination and if needed could delete it (help can be seen by passing /h).

Broadcast receiver for checking internet connection in android app

Checking internet status every time using Broadcast Receiver:

internet status implementation

Full source code available on Google Drive.

AndroidManifest.xml

<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>
<uses-permission android:name="android.permission.INTERNET"/>
<receiver android:name=".receivers.NetworkChangeReceiver">
            <intent-filter>
                <action android:name="android.net.conn.CONNECTIVITY_CHANGE" />
            </intent-filter>
</receiver>

BroadcastReciever

package com.keshav.networkchangereceiverexample.receivers;

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.util.Log;

import static com.keshav.networkchangereceiverexample.MainActivity.dialog;

public class NetworkChangeReceiver extends BroadcastReceiver
{
    @Override
    public void onReceive(Context context, Intent intent)
    {
        try
        {
            if (isOnline(context)) {
                dialog(true);
                Log.e("keshav", "Online Connect Intenet ");
            } else {
                dialog(false);
                Log.e("keshav", "Conectivity Failure !!! ");
            }
        } catch (NullPointerException e) {
            e.printStackTrace();
        }
    }

    private boolean isOnline(Context context) {
        try {
            ConnectivityManager cm = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
            NetworkInfo netInfo = cm.getActiveNetworkInfo();
            //should check null because in airplane mode it will be null
            return (netInfo != null && netInfo.isConnected());
        } catch (NullPointerException e) {
            e.printStackTrace();
            return false;
        }
    }
}

MainActivity.java

package com.keshav.networkchangereceiverexample;

import android.content.BroadcastReceiver;
import android.content.Intent;
import android.content.IntentFilter;
import android.graphics.Color;
import android.net.ConnectivityManager;
import android.os.Build;
import android.os.Handler;
import android.os.Looper;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.view.animation.Animation;
import android.view.animation.AnimationUtils;
import android.widget.TextView;

import com.keshav.networkchangereceiverexample.receivers.NetworkChangeReceiver;

public class MainActivity extends AppCompatActivity {

    private BroadcastReceiver mNetworkReceiver;
    static TextView tv_check_connection;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        tv_check_connection=(TextView) findViewById(R.id.tv_check_connection);
        mNetworkReceiver = new NetworkChangeReceiver();
        registerNetworkBroadcastForNougat();

    }

    public static void dialog(boolean value){

        if(value){
            tv_check_connection.setText("We are back !!!");
            tv_check_connection.setBackgroundColor(Color.GREEN);
            tv_check_connection.setTextColor(Color.WHITE);

            Handler handler = new Handler();
            Runnable delayrunnable = new Runnable() {
                @Override
                public void run() {
                    tv_check_connection.setVisibility(View.GONE);
                }
            };
            handler.postDelayed(delayrunnable, 3000);
        }else {
            tv_check_connection.setVisibility(View.VISIBLE);
            tv_check_connection.setText("Could not Connect to internet");
            tv_check_connection.setBackgroundColor(Color.RED);
            tv_check_connection.setTextColor(Color.WHITE);
        }
    }


    private void registerNetworkBroadcastForNougat() {
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
            registerReceiver(mNetworkReceiver, new IntentFilter(ConnectivityManager.CONNECTIVITY_ACTION));
        }
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
            registerReceiver(mNetworkReceiver, new IntentFilter(ConnectivityManager.CONNECTIVITY_ACTION));
        }
    }

    protected void unregisterNetworkChanges() {
        try {
            unregisterReceiver(mNetworkReceiver);
        } catch (IllegalArgumentException e) {
            e.printStackTrace();
        }
    }

    @Override
    public void onDestroy() {
        super.onDestroy();
        unregisterNetworkChanges();
    }
}

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.keshav.networkchangereceiverexample.MainActivity">

    <TextView
        android:id="@+id/tv_check_connection"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Connection establised !"
        android:padding="25dp"
        app:layout_constraintBottom_toBottomOf="parent"
        android:gravity="center"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

</LinearLayout>

Overflow-x:hidden doesn't prevent content from overflowing in mobile browsers

The only way to fix this issue for my bootstrap modal (containing a form) was to add the following code to my CSS:

.modal {
    -webkit-overflow-scrolling: auto!important;
}

adding to window.onload event?

This might not be a popular option, but sometimes the scripts end up being distributed in various chunks, in that case I've found this to be a quick fix

if(window.onload != null){var f1 = window.onload;}
window.onload=function(){
    //do something

    if(f1!=null){f1();}
}

then somewhere else...

if(window.onload != null){var f2 = window.onload;}
window.onload=function(){
    //do something else

    if(f2!=null){f2();}
}

this will update the onload function and chain as needed

Quicker way to get all unique values of a column in VBA?

Loading the values in an array would be much faster:

Dim data(), dict As Object, r As Long
Set dict = CreateObject("Scripting.Dictionary")

data = ActiveSheet.UsedRange.Columns(1).Value

For r = 1 To UBound(data)
    dict(data(r, some_column_number)) = Empty
Next

data = WorksheetFunction.Transpose(dict.keys())

You should also consider early binding for the Scripting.Dictionary:

Dim dict As New Scripting.Dictionary  ' requires `Microsoft Scripting Runtime` '

Note that using a dictionary is way faster than Range.AdvancedFilter on large data sets.

As a bonus, here's a procedure similare to Range.RemoveDuplicates to remove duplicates from a 2D array:

Public Sub RemoveDuplicates(data, ParamArray columns())
    Dim ret(), indexes(), ids(), r As Long, c As Long
    Dim dict As New Scripting.Dictionary  ' requires `Microsoft Scripting Runtime` '

    If VarType(data) And vbArray Then Else Err.Raise 5, , "Argument data is not an array"

    ReDim ids(LBound(columns) To UBound(columns))

    For r = LBound(data) To UBound(data)         ' each row '
        For c = LBound(columns) To UBound(columns)   ' each column '
            ids(c) = data(r, columns(c))                ' build id for the row
        Next
        dict(Join$(ids, ChrW(-1))) = r  ' associate the row index to the id '
    Next

    indexes = dict.Items()
    ReDim ret(LBound(data) To LBound(data) + dict.Count - 1, LBound(data, 2) To UBound(data, 2))

    For c = LBound(ret, 2) To UBound(ret, 2)  ' each column '
        For r = LBound(ret) To UBound(ret)      ' each row / unique id '
            ret(r, c) = data(indexes(r - 1), c)   ' copy the value at index '
        Next
    Next

    data = ret
End Sub

How to add a second css class with a conditional value in razor MVC 4

You can add property to your model as follows:

    public string DetailsClass { get { return Details.Count > 0 ? "show" : "hide" } }

and then your view will be simpler and will contain no logic at all:

    <div class="details @Model.DetailsClass"/>

This will work even with many classes and will not render class if it is null:

    <div class="@Model.Class1 @Model.Class2"/>

with 2 not null properties will render:

    <div class="class1 class2"/>

if class1 is null

    <div class=" class2"/>

Self-references in object literals / initializers

You could do something like:

var foo = {
   a: 5,
   b: 6,
   init: function() {
       this.c = this.a + this.b;
       return this;
   }
}.init();

This would be some kind of one time initialization of the object.

Note that you are actually assigning the return value of init() to foo, therefore you have to return this.

Temporarily switch working copy to a specific Git commit

If you are at a certain branch mybranch, just go ahead and git checkout commit_hash. Then you can return to your branch by git checkout mybranch. I had the same game bisecting a bug today :) Also, you should know about git bisect.

"The system cannot find the file C:\ProgramData\Oracle\Java\javapath\java.exe"

<>\Common Files\Oracle\Java\javapath\ is now created as a junction, no symlinks anymore

How can I use external JARs in an Android project?

create a folder (like lib) inside your project, copy your jar to that folder. now go to configure build path from right click on project, there in build path select

'add jar' browse to the folder you created and pick the jar.

Submitting HTML form using Jquery AJAX

var postData = "text";
      $.ajax({
            type: "post",
            url: "url",
            data: postData,
            contentType: "application/x-www-form-urlencoded",
            success: function(responseData, textStatus, jqXHR) {
                alert("data saved")
            },
            error: function(jqXHR, textStatus, errorThrown) {
                console.log(errorThrown);
            }
        })

Maven: Failed to retrieve plugin descriptor error

I had the same issue in Windows

and it worked since my proxy configuration in settings.xml file was changed

So locate and edit the file inside the \conf folder, for example : C:\Program Files\apache-maven-3.2.5\conf

<proxies>
    <!-- proxy
     | Specification for one proxy, to be used in connecting to the network.
     |
    <proxy>
      <id>optional</id>
      <active>true</active>
      <protocol>http</protocol>
      <username>jorgesys</username>
      <password>supercalifragilisticoespialidoso</password>
      <host>proxyjorgesys</host>
      <port>8080</port>
      <nonProxyHosts>local.net|some.host.com</nonProxyHosts>
    </proxy>
    -->
  </proxies>
  • In my case i had to chage from port 80 to 8080
  • If you can´t edit this file that is located inside /program files you can make a copy, edit the file and replace the file located into /program files folder.

$this->session->set_flashdata() and then $this->session->flashdata() doesn't work in codeigniter

To set flashdata you need to redirect controller function

$this->session->set_flashdata('message_name', 'This is test message');

//redirect to some function
redirect("controller/function_name");

//echo in view or controller
$this->session->flashdata('message_name');

Returning a promise in an async function in TypeScript

It's complicated.

First of all, in this code

const p = new Promise((resolve) => {
    resolve(4);
});

the type of p is inferred as Promise<{}>. There is open issue about this on typescript github, so arguably this is a bug, because obviously (for a human), p should be Promise<number>.

Then, Promise<{}> is compatible with Promise<number>, because basically the only property a promise has is then method, and then is compatible in these two promise types in accordance with typescript rules for function types compatibility. That's why there is no error in whatever1.

But the purpose of async is to pretend that you are dealing with actual values, not promises, and then you get the error in whatever2 because {} is obvioulsy not compatible with number.

So the async behavior is the same, but currently some workaround is necessary to make typescript compile it. You could simply provide explicit generic argument when creating a promise like this:

const whatever2 = async (): Promise<number> => {
    return new Promise<number>((resolve) => {
        resolve(4);
    });
};

Python: how to capture image from webcam on click using OpenCV

i'm not too experienced with open cv but if you want the code in the for loop to be called when a key is pressed, you can use a while loop and an raw_input and a condition to prevent the loop from executing forever

import cv2

camera = cv2.VideoCapture(0)
i = 0
while i < 10:
    raw_input('Press Enter to capture')
    return_value, image = camera.read()
    cv2.imwrite('opencv'+str(i)+'.png', image)
    i += 1
del(camera)

Remove rows not .isin('X')

You have many options. Collating some of the answers above and the accepted answer from this post you can do:
1. df[-df["column"].isin(["value"])]
2. df[~df["column"].isin(["value"])]
3. df[df["column"].isin(["value"]) == False]
4. df[np.logical_not(df["column"].isin(["value"]))]

Note: for option 4 for you'll need to import numpy as np

Update: You can also use the .query method for this too. This allows for method chaining:
5. df.query("column not in @values").
where values is a list of the values that you don't want to include.

Programmatically Install Certificate into Mozilla

Firefox now (since 58) uses a SQLite database cert9.db instead of legacy cert8.db. I have made a fix to a solution presented here to make it work with new versions of Firefox:

certificateFile="MyCa.cert.pem"
certificateName="MyCA Name" 
for certDB in $(find  ~/.mozilla* ~/.thunderbird -name "cert9.db")
do
  certDir=$(dirname ${certDB});
  #log "mozilla certificate" "install '${certificateName}' in ${certDir}"
  certutil -A -n "${certificateName}" -t "TCu,Cuw,Tuw" -i ${certificateFile} -d sql:${certDir}
done

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

You don't need to declare them as arrays if you want to use use them as pointers. You can simply reference pointers as if they were multi-dimensional arrays. Just create it as a pointer to a pointer and use malloc:

int i;
int M=30, N=25;
int ** buf;
buf = (int**) malloc(M * sizeof(int*));
for(i=0;i<M;i++)
    buf[i] = (int*) malloc(N * sizeof(int));

and then you can reference buf[3][5] or whatever.

Connecting to a network folder with username/password in Powershell

This is not a PowerShell-specific answer, but you could authenticate against the share using "NET USE" first:

net use \\server\share /user:<domain\username> <password>

And then do whatever you need to do in PowerShell...

How to break out from a ruby block?

If you want your block to return a useful value (e.g. when using #map, #inject, etc.), next and break also accept an argument.

Consider the following:

def contrived_example(numbers)
  numbers.inject(0) do |count, x|
    if x % 3 == 0
      count + 2
    elsif x.odd?
      count + 1
    else 
      count
    end
  end
end

The equivalent using next:

def contrived_example(numbers)
  numbers.inject(0) do |count, x|
    next count if x.even?
    next (count + 2) if x % 3 == 0
    count + 1
  end
end

Of course, you could always extract the logic needed into a method and call that from inside your block:

def contrived_example(numbers)
  numbers.inject(0) { |count, x| count + extracted_logic(x) }
end

def extracted_logic(x)
  return 0 if x.even?
  return 2 if x % 3 == 0
  1
end

Adding a regression line on a ggplot

I found this function on a blog

 ggplotRegression <- function (fit) {

    `require(ggplot2)

    ggplot(fit$model, aes_string(x = names(fit$model)[2], y = names(fit$model)[1])) + 
      geom_point() +
      stat_smooth(method = "lm", col = "red") +
      labs(title = paste("Adj R2 = ",signif(summary(fit)$adj.r.squared, 5),
                         "Intercept =",signif(fit$coef[[1]],5 ),
                         " Slope =",signif(fit$coef[[2]], 5),
                         " P =",signif(summary(fit)$coef[2,4], 5)))
    }`

once you loaded the function you could simply

ggplotRegression(fit)

you can also go for ggplotregression( y ~ x + z + Q, data)

Hope this helps.

Plot size and resolution with R markdown, knitr, pandoc, beamer

I think that is a frequently asked question about the behavior of figures in beamer slides produced from Pandoc and markdown. The real problem is, R Markdown produces PNG images by default (from knitr), and it is hard to get the size of PNG images correct in LaTeX by default (I do not know why). It is fairly easy, however, to get the size of PDF images correct. One solution is to reset the default graphical device to PDF in your first chunk:

```{r setup, include=FALSE}
knitr::opts_chunk$set(dev = 'pdf')
```

Then all the images will be written as PDF files, and LaTeX will be happy.

Your second problem is you are mixing up the HTML units with LaTeX units in out.width / out.height. LaTeX and HTML are very different technologies. You should not expect \maxwidth to work in HTML, or 200px in LaTeX. Especially when you want to convert Markdown to LaTeX, you'd better not set out.width / out.height (use fig.width / fig.height and let LaTeX use the original size).

pandas GroupBy columns with NaN (missing) values

This is mentioned in the Missing Data section of the docs:

NA groups in GroupBy are automatically excluded. This behavior is consistent with R

One workaround is to use a placeholder before doing the groupby (e.g. -1):

In [11]: df.fillna(-1)
Out[11]: 
   a   b
0  1   4
1  2  -1
2  3   6

In [12]: df.fillna(-1).groupby('b').sum()
Out[12]: 
    a
b    
-1  2
4   1
6   3

That said, this feels pretty awful hack... perhaps there should be an option to include NaN in groupby (see this github issue - which uses the same placeholder hack).

However, as described in another answer, "from pandas 1.1 you have better control over this behavior, NA values are now allowed in the grouper using dropna=False"

How can I interrupt a running code in R with a keyboard command?

Self Answer (pretty much summary of other's comments and answers):

  • In RStudio, Esc works, on windows, Mac, and ubuntu (and I would guess on other linux distributions as well).

  • If the process is ran in say ubuntu shell (and this is not R specific), for example using:

    Rscript my_file.R
    

    Ctrl + c kills the process

    Ctrl + z suspends the process

  • Within R shell, Ctrl + C kills helps you escape it

Angularjs on page load call function

It's not the angular way, remove the function from html body and use it in controller, or use

angular.element(document).ready

More details are available here: https://stackoverflow.com/a/18646795/4301583

PHPExcel Make first row bold

$objPHPExcel->getActiveSheet()->getStyle("A1:".$objPHPExcel->getActiveSheet()->getHighestDataColumn()."1")->getFont()->setBold(true);

I found this to be a working solution, you can replace the two instances of 1 with the row number. The HighestDataColumn function returns for example C or Z, it gives you the last/highest column that's in the sheet containing any data. There is also getHighestColumn(), that one would include cells that are empty but have styling or are part of other functionality.

JSON.net: how to deserialize without using the default constructor?

A bit late and not exactly suited here, but I'm gonna add my solution here, because my question had been closed as a duplicate of this one, and because this solution is completely different.

I needed a general way to instruct Json.NET to prefer the most specific constructor for a user defined struct type, so I can omit the JsonConstructor attributes which would add a dependency to the project where each such struct is defined.

I've reverse engineered a bit and implemented a custom contract resolver where I've overridden the CreateObjectContract method to add my custom creation logic.

public class CustomContractResolver : DefaultContractResolver {

    protected override JsonObjectContract CreateObjectContract(Type objectType)
    {
        var c = base.CreateObjectContract(objectType);
        if (!IsCustomStruct(objectType)) return c;

        IList<ConstructorInfo> list = objectType.GetConstructors(BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic).OrderBy(e => e.GetParameters().Length).ToList();
        var mostSpecific = list.LastOrDefault();
        if (mostSpecific != null)
        {
            c.OverrideCreator = CreateParameterizedConstructor(mostSpecific);
            c.CreatorParameters.AddRange(CreateConstructorParameters(mostSpecific, c.Properties));
        }

        return c;
    }

    protected virtual bool IsCustomStruct(Type objectType)
    {
        return objectType.IsValueType && !objectType.IsPrimitive && !objectType.IsEnum && !objectType.Namespace.IsNullOrEmpty() && !objectType.Namespace.StartsWith("System.");
    }

    private ObjectConstructor<object> CreateParameterizedConstructor(MethodBase method)
    {
        method.ThrowIfNull("method");
        var c = method as ConstructorInfo;
        if (c != null)
            return a => c.Invoke(a);
        return a => method.Invoke(null, a);
    }
}

I'm using it like this.

public struct Test {
  public readonly int A;
  public readonly string B;

  public Test(int a, string b) {
    A = a;
    B = b;
  }
}

var json = JsonConvert.SerializeObject(new Test(1, "Test"), new JsonSerializerSettings {
  ContractResolver = new CustomContractResolver()
});
var t = JsonConvert.DeserializeObject<Test>(json);
t.A.ShouldEqual(1);
t.B.ShouldEqual("Test");

What is the difference between ArrayList.clear() and ArrayList.removeAll()?

Unless there is a specific optimization that checks if the argument passed to removeAll() is the collection itself (and I highly doubt that such an optimization is there) it will be significantly slower than a simple .clear().

Apart from that (and at least equally important): arraylist.removeAll(arraylist) is just obtuse, confusing code. It is a very backwards way of saying "clear this collection". What advantage would it have over the very understandable arraylist.clear()?

Check if a string is html or not

Since the original request is not say the solution had to be a RegExp, just that an attempt to use a RegExp was being made. I will offer this up. It says something is HTML if a single child element can be parsed. Note, this will return false if the body contains only comments or CDATA or server directives.

const isHTML = (text) => {
  try {
    const fragment = new DOMParser().parseFromString(text,"text/html");
    return fragment.body.children.length>0
  } catch(error) { ; }  
  return false;
}

How to delete zero components in a vector in Matlab?

If you just wish to remove the zeros, leaving the non-zeros behind in a, then the very best solution is

a(a==0) = [];

This deletes the zero elements, using a logical indexing approach in MATLAB. When the index to a vector is a boolean vector of the same length as the vector, then MATLAB can use that boolean result to index it with. So this is equivalent to

a(find(a==0)) = [];

And, when you set some array elements to [] in MATLAB, the convention is to delete them.

If you want to put the zeros into a new result b, while leaving a unchanged, the best way is probably

b = a(a ~= 0);

Again, logical indexing is used here. You could have used the equivalent version (in terms of the result) of

b = a(find(a ~= 0));

but mlint will end up flagging the line as one where the purely logical index was more efficient, and thus more appropriate.

As always, beware EXACT tests for zero or for any number, if you would have accepted elements of a that were within some epsilonic tolerance of zero. Do those tests like this

b = a(abs(a) >= tol);

This retains only those elements of a that are at least as large as your tolerance.

MVC web api: No 'Access-Control-Allow-Origin' header is present on the requested resource

@Mihai-Andrei Dinculescu's answer worked for me, e.g.:

  • Adding a <httpProtocol>in the web.config's <system.webServer> section
  • Returning empty response for OPTIONS requests via the mentioned Application_BeginRequest() in global.asax

Except that his check for Request.Headers.AllKeys.Contains("Origin") did NOT work for me, because the request contained an origing, so with lowercase. I think my browser (Chrome) sends it like this for CORS requests.

I solved this a bit more generically by using a case insensitive variant of his Contains check instead: if (culture.CompareInfo.IndexOf(string.Join(",", Request.Headers.AllKeys), "Origin", CompareOptions.IgnoreCase) >= 0) {

How do you use youtube-dl to download live streams (that are live)?

I have Written a small script to download the live youtube video, you may use as single command as well. script it can be invoked simply as,

~/ytdl_lv.sh <URL> <output file name>

e.g.

~/ytdl_lv.sh https://www.youtube.com/watch?v=BLIGxsYLyjc myfile.mp4

script is as simple as below,

#!/bin/bash 

# ytdl_lv.sh
# Author Prashant
# 

URL=$1 
OUTNAME=$2
streamlink --hls-live-restart -o ${OUTNAME} ${URL} best

here the best is the stream quality, it also can be 144p (worst), 240p, 360p, 480p, 720p (best)

Reliable way to convert a file to a byte[]

Others have noted that you can use the built-in File.ReadAllBytes. The built-in method is fine, but it's worth noting that the code you post above is fragile for two reasons:

  1. Stream is IDisposable - you should place the FileStream fs = new FileStream(filename, FileMode.Open,FileAccess.Read) initialization in a using clause to ensure the file is closed. Failure to do this may mean that the stream remains open if a failure occurs, which will mean the file remains locked - and that can cause other problems later on.
  2. fs.Read may read fewer bytes than you request. In general, the .Read method of a Stream instance will read at least one byte, but not necessarily all bytes you ask for. You'll need to write a loop that retries reading until all bytes are read. This page explains this in more detail.

How to filter for multiple criteria in Excel?

Maybe not as elegant but another possibility would be to write a formula to do the check and fill it in an adjacent column. You could then filter on that column.

The following looks in cell b14 and would return true for all the file types you mention. This assumes that the file extension is by itself in the column. If it's not it would be a little more complicated but you could still do it this way.

=OR(B14=".pdf",B14=".doc",B14=".docx",B14=".xls",B14=".xlsx",B14=".rtf",B14=".txt",B14=".csv",B14=".pps")

Like I said, not as elegant as the advanced filters but options are always good.

Getting a random value from a JavaScript array

The shortest version:

var myArray = ['January', 'February', 'March']; 
var rand = myArray[(Math.random() * myArray.length) | 0]

Deep-Learning Nan loss reasons

The reason for nan, inf or -inf often comes from the fact that division by 0.0 in TensorFlow doesn't result in a division by zero exception. It could result in a nan, inf or -inf "value". In your training data you might have 0.0 and thus in your loss function it could happen that you perform a division by 0.0.

a = tf.constant([2., 0., -2.])
b = tf.constant([0., 0., 0.])
c = tf.constant([1., 1., 1.])
print((a / b) + c)

Output is the following tensor:

tf.Tensor([ inf  nan -inf], shape=(3,), dtype=float32)

Adding a small eplison (e.g., 1e-5) often does the trick. Additionally, since TensorFlow 2 the opteration tf.math.division_no_nan is defined.

How do I remove packages installed with Python's easy_install?

If the problem is a serious-enough annoyance to you, you might consider virtualenv. It allows you to create an environment that encapsulates python libraries. You install packages there rather than in the global site-packages directory. Any scripts you run in that environment have access to those packages (and optionally, your global ones as well). I use this a lot when evaluating packages that I am not sure I want/need to install globally. If you decide you don't need the package, it's easy enough to just blow that virtual environment away. It's pretty easy to use. Make a new env:

$>virtualenv /path/to/your/new/ENV

virtual_envt installs setuptools for you in the new environment, so you can do:

$>ENV/bin/easy_install

You can even create your own boostrap scripts that setup your new environment. So, with one command, you can create a new virtual env with, say, python 2.6, psycopg2 and django installed by default (you can can install an env-specific version of python if you want).

CSS last-child selector: select last-element of specific class, not last child inside of parent?

I guess that the most correct answer is: Use :nth-child (or, in this specific case, its counterpart :nth-last-child). Most only know this selector by its first argument to grab a range of items based on a calculation with n, but it can also take a second argument "of [any CSS selector]".

Your scenario could be solved with this selector: .commentList .comment:nth-last-child(1 of .comment)

But being technically correct doesn't mean you can use it, though, because this selector is as of now only implemented in Safari.

For further reading:

How to get the last character of a string in a shell?

another solution using awk script:

last 1 char:

echo $str | awk '{print substr($0,length,1)}'

last 5 chars:

echo $str | awk '{print substr($0,length-5,5)}'

How to set the java.library.path from Eclipse

If you are adding it as a VM argument, make sure you prefix it with -D:

-Djava.library.path=blahblahblah...

TypeError: can't pickle _thread.lock objects

I had the same problem with Pool() in Python 3.6.3.

Error received: TypeError: can't pickle _thread.RLock objects

Let's say we want to add some number num_to_add to each element of some list num_list in parallel. The code is schematically like this:

class DataGenerator:
    def __init__(self, num_list, num_to_add)
        self.num_list = num_list # e.g. [4,2,5,7]
        self.num_to_add = num_to_add # e.g. 1 

        self.run()

    def run(self):
        new_num_list = Manager().list()

        pool = Pool(processes=50)
        results = [pool.apply_async(run_parallel, (num, new_num_list)) 
                      for num in num_list]
        roots = [r.get() for r in results]
        pool.close()
        pool.terminate()
        pool.join()

    def run_parallel(self, num, shared_new_num_list):
        new_num = num + self.num_to_add # uses class parameter
        shared_new_num_list.append(new_num)

The problem here is that self in function run_parallel() can't be pickled as it is a class instance. Moving this parallelized function run_parallel() out of the class helped. But it's not the best solution as this function probably needs to use class parameters like self.num_to_add and then you have to pass it as an argument.

Solution:

def run_parallel(num, shared_new_num_list, to_add): # to_add is passed as an argument
    new_num = num + to_add
    shared_new_num_list.append(new_num)

class DataGenerator:
    def __init__(self, num_list, num_to_add)
        self.num_list = num_list # e.g. [4,2,5,7]
        self.num_to_add = num_to_add # e.g. 1

        self.run()

    def run(self):
        new_num_list = Manager().list()

        pool = Pool(processes=50)
        results = [pool.apply_async(run_parallel, (num, new_num_list, self.num_to_add)) # num_to_add is passed as an argument
                      for num in num_list]
        roots = [r.get() for r in results]
        pool.close()
        pool.terminate()
        pool.join()

Other suggestions above didn't help me.

what is an illegal reflective access

Just look at setAccessible() method used to access private fields and methods:

https://docs.oracle.com/javase/8/docs/api/java/lang/reflect/AccessibleObject.html#setAccessible-boolean-

https://docs.oracle.com/javase/9/docs/api/java/lang/reflect/AccessibleObject.html#setAccessible-boolean-

Now there is a lot more conditions required for this method to work. The only reason it doesn't break almost all of older software is that modules autogenerated from plain JARs are very permissive (open and export everything for everyone).

How to uninstall a Windows Service when there is no executable for it left on the system?

found here

I just tried on windows XP, it worked

local computer: sc \\. delete [service-name]

  Deleting services in Windows Server 2003

  We can use sc.exe in the Windows Server 2003 to control services, create services and delete services. Since some people thought they must directly modify the registry to delete a service, I would like to share how to use sc.exe to delete a service without directly modifying the registry so that decreased the possibility for system failures.

  To delete a service: 

  Click “start“ - “run“, and then enter “cmd“ to open Microsoft Command Console.

  Enter command:

  sc servername delete servicename

  For instance, sc \\dc delete myservice

  (Note: In this example, dc is my Domain Controller Server name, which is not the local machine, myservice is the name of the service I want to delete on the DC server.)

  Below is the official help of all sc functions:

  DESCRIPTION:
    SC is a command line program used for communicating with the
    NT Service Controller and services. 
  USAGE:
          sc

How to solve java.lang.NoClassDefFoundError?

NoClassDefFoundError means that the class is present in the classpath at Compile time, but it doesn't exist in the classpath at Runtime.

If you're using Eclipse, make sure you have the shapes, linepoints and the spaceobjects as entries in the .classpath file.

Save a list to a .txt file

If you have more then 1 dimension array

with open("file.txt", 'w') as output:
    for row in values:
        output.write(str(row) + '\n')

Code to write without '[' and ']'

with open("file.txt", 'w') as file:
        for row in values:
            s = " ".join(map(str, row))
            file.write(s+'\n')

Compile/run assembler in Linux?

If you are using NASM, the command-line is just

nasm -felf32 -g -Fdwarf file.asm -o file.o

where 'file.asm' is your assembly file (code) and 'file.o' is an object file you can link with gcc -m32 or ld -melf_i386. (Assembling with nasm -felf64 will make a 64-bit object file, but the hello world example below uses 32-bit system calls, and won't work in a PIE executable.)

Here is some more info:

http://www.nasm.us/doc/nasmdoc2.html#section-2.1

You can install NASM in Ubuntu with the following command:

apt-get install nasm

Here is a basic Hello World in Linux assembly to whet your appetite:

http://web.archive.org/web/20120822144129/http://www.cin.ufpe.br/~if817/arquivos/asmtut/index.html

I hope this is what you were asking...

Check whether values in one data frame column exist in a second data frame

Use %in% as follows

A$C %in% B$C

Which will tell you which values of column C of A are in B.

What is returned is a logical vector. In the specific case of your example, you get:

A$C %in% B$C
# [1]  TRUE FALSE  TRUE  TRUE

Which you can use as an index to the rows of A or as an index to A$C to get the actual values:

# as a row index
A[A$C %in% B$C,  ]  # note the comma to indicate we are indexing rows

# as an index to A$C
A$C[A$C %in% B$C]
[1] 1 3 4  # returns all values of A$C that are in B$C

We can negate it too:

A$C[!A$C %in% B$C]
[1] 2   # returns all values of A$C that are NOT in B$C



If you want to know if a specific value is in B$C, use the same function:

  2 %in% B$C   # "is the value 2 in B$C ?"  
  # FALSE

  A$C[2] %in% B$C  # "is the 2nd element of A$C in B$C ?"  
  # FALSE

Best way to get identity of inserted row?

I'm saying the same thing as the other guys, so everyone's correct, I'm just trying to make it more clear.

@@IDENTITY returns the id of the last thing that was inserted by your client's connection to the database.
Most of the time this works fine, but sometimes a trigger will go and insert a new row that you don't know about, and you'll get the ID from this new row, instead of the one you want

SCOPE_IDENTITY() solves this problem. It returns the id of the last thing that you inserted in the SQL code you sent to the database. If triggers go and create extra rows, they won't cause the wrong value to get returned. Hooray

IDENT_CURRENT returns the last ID that was inserted by anyone. If some other app happens to insert another row at an unforunate time, you'll get the ID of that row instead of your one.

If you want to play it safe, always use SCOPE_IDENTITY(). If you stick with @@IDENTITY and someone decides to add a trigger later on, all your code will break.

Check if $_POST exists

if( isset($_POST['fromPerson']) ) is right.

You can use a function and return, better then directing echo.

RecyclerView and java.lang.IndexOutOfBoundsException: Inconsistency detected. Invalid view holder adapter positionViewHolder in Samsung devices

I had a similar problem.

Problem in error code below:

int prevSize = messageListHistory.size();
// some insert
adapter.notifyItemRangeInserted(prevSize - 1, messageListHistory.size() -1);

Solution:

int prevSize = messageListHistory.size();
// some insert
adapter.notifyItemRangeInserted(prevSize, messageListHistory.size() -prevSize);

Spring Boot, Spring Data JPA with multiple DataSources

I checked the source code you provided on GitHub. There were several mistakes / typos in the configuration.

In CustomerDbConfig / OrderDbConfig you should refer to customerEntityManager and packages should point at existing packages:

@Configuration
@EnableJpaRepositories(
    entityManagerFactoryRef = "customerEntityManager",
    transactionManagerRef = "customerTransactionManager",
    basePackages = {"com.mm.boot.multidb.repository.customer"})
public class CustomerDbConfig {

The packages to scan in customerEntityManager and orderEntityManager were both not pointing at proper package:

em.setPackagesToScan("com.mm.boot.multidb.model.customer");

Also the injection of proper EntityManagerFactory did not work. It should be:

@Bean(name = "customerTransactionManager")
public PlatformTransactionManager transactionManager(EntityManagerFactory customerEntityManager){

}

The above was causing the issue and the exception. While providing the name in a @Bean method you are sure you get proper EMF injected.

The last thing I have done was to disable to automatic configuration of JpaRepositories:

@EnableAutoConfiguration(exclude = JpaRepositoriesAutoConfiguration.class)

And with all fixes the application starts as you probably expect!

How to change fonts in matplotlib (python)?

Say you want Comic Sans for the title and Helvetica for the x label.

csfont = {'fontname':'Comic Sans MS'}
hfont = {'fontname':'Helvetica'}

plt.title('title',**csfont)
plt.xlabel('xlabel', **hfont)
plt.show()

Send form data using ajax

as far as we want to send all the form input fields which have name attribute, you can do this for all forms, regardless of the field names:

First Solution

function submitForm(form){
    var url = form.attr("action");
    var formData = {};
    $(form).find("input[name]").each(function (index, node) {
        formData[node.name] = node.value;
    });
    $.post(url, formData).done(function (data) {
        alert(data);
    });
}

Second Solution: in this solution you can create an array of input values:

function submitForm(form){
    var url = form.attr("action");
    var formData = $(form).serializeArray();
    $.post(url, formData).done(function (data) {
        alert(data);
    });
}

bootstrap datepicker change date event doesnt fire up when manually editing dates or clearing date

I have this version about datetimepicker https://tempusdominus.github.io/bootstrap-4/ and for any reason doesn`t work the change event with jquery but with JS vanilla it does

I figure out like this

document.getElementById('date').onchange = function(){ ...the jquery code...}

I hope work for you

How to remove element from ArrayList by checking its value?

Use a iterator to loop through list and then delete the required object.

    Iterator itr = a.iterator();
    while(itr.hasNext()){
        if(itr.next().equals("acbd"))
            itr.remove();
    }

SQL to Entity Framework Count Group-By

Edit: EF Core 2.1 finally supports GroupBy

But always look out in the console / log for messages. If you see a notification that your query could not be converted to SQL and will be evaluated locally then you may need to rewrite it.


Entity Framework 7 (now renamed to Entity Framework Core 1.0 / 2.0) does not yet support GroupBy() for translation to GROUP BY in generated SQL (even in the final 1.0 release it won't). Any grouping logic will run on the client side, which could cause a lot of data to be loaded.

Eventually code written like this will automagically start using GROUP BY, but for now you need to be very cautious if loading your whole un-grouped dataset into memory will cause performance issues.

For scenarios where this is a deal-breaker you will have to write the SQL by hand and execute it through EF.

If in doubt fire up Sql Profiler and see what is generated - which you should probably be doing anyway.

https://blogs.msdn.microsoft.com/dotnet/2016/05/16/announcing-entity-framework-core-rc2

What's the difference between ISO 8601 and RFC 3339 Date Formats?

RFC 3339 is mostly a profile of ISO 8601, but is actually inconsistent with it in borrowing the "-00:00" timezone specification from RFC 2822. This is described in the Wikipedia article.

remove space between paragraph and unordered list

I ended up using a definition list with an unordered list inside it. It solves the issue of the unwanted space above the list without needing to change every paragraph tag.

<dl><dt>Text</dt>
<dd><ul><li>First item</li>
<li>Second item</li></ul></dd></dl>

How to add to an NSDictionary

You want to ask is "what is the difference between a mutable and a non-mutable array or dictionary." Many times there different terms are used to describe things that you already know about. In this case, you can replace the term "mutable" with "dynamic." So, a mutuable dictionary or array is one that is "dynamic" and can change at runtime, whereas a non-mutable dictionary or array is one that is "static" and defined in your code and does not change at runtime (in other words, you will not be adding, deleting or possibly sorting the elements.)

As to how it is done, you are asking us to repeat the documentation here. All you need to do is to search in sample code and the Xcode documentation to see exactly how it is done. But the mutable thing threw me too when I was first learning, so I'll give you that one!

How to add elements to a list in R (loop)

You should not add to your list using c inside the loop, because that can result in very very slow code. Basically when you do c(l, new_element), the whole contents of the list are copied. Instead of that, you need to access the elements of the list by index. If you know how long your list is going to be, it's best to initialise it to this size using l <- vector("list", N). If you don't you can initialise it to have length equal to some large number (e.g if you have an upper bound on the number of iterations) and then just pick the non-NULL elements after the loop has finished. Anyway, the basic point is that you should have an index to keep track of the list element and add using that eg

i <- 1
while(...) {
    l[[i]] <- new_element
    i <- i + 1
}

For more info have a look at Patrick Burns' The R Inferno (Chapter 2).

TypeError: cannot perform reduce with flexible type

It looks like your 'trainData' is a list of strings:

['-214' '-153' '-58' ..., '36' '191' '-37']

Change your 'trainData' to a numeric type.

 import numpy as np
 np.array(['1','2','3']).astype(np.float)

How to sort an array of associative arrays by value of a given key in PHP?

You can use usort with anonymous function, e.g.

usort($inventory, function ($a, $b) { return strnatcmp($a['price'], $b['price']); });

How to split a delimited string in Ruby and convert it to an array?

>> "1,2,3,4".split(",")
=> ["1", "2", "3", "4"]

Or for integers:

>> "1,2,3,4".split(",").map { |s| s.to_i }
=> [1, 2, 3, 4]

Or for later versions of ruby (>= 1.9 - as pointed out by Alex):

>> "1,2,3,4".split(",").map(&:to_i)
=> [1, 2, 3, 4]

Why am I getting tree conflicts in Subversion?

This can be caused by not using the same version clients all over.

Using a version 1.5 client and a version 1.6 client towards the same repository can create this kind of problem. (I was just bitten myself.)

How can I get the Google cache age of any URL or web page?

you can Use CachedPages website

Cached pages are usually saved and stored by large companies with powerful web servers. Since such servers are usually very fast, a cached page can often be accessed faster than the live page itself:

  • Google usually keeps a recent copy of the page (1 to 15 days old).
  • Coral also keeps a recent copy, although it's usually not as recent as Google.
  • Through Archive.org, you can access several copies of a web page saved throughout the years.

Ternary operator ?: vs if...else

In C A ternary operator " ? : " is available to construct conditional expressions of the form

exp1 ? exp2:exp3

where exp1,exp2 and exp3 are expressions

for Example

        a=20;
        b=25;
        x=(a>b)?a:b;

        in the above example x value will be assigned to b;

This can be written using if..else statement as follows

            if (a>b)
             x=a;
             else
             x=b;

**Hence there is no difference between these two. This for the programmer to write easily, but for compiler both are same.*

How do I link object files in C? Fails with "Undefined symbols for architecture x86_64"

Add foo1.c , foo2.c , foo3.c and makefile in one folder the type make in bash

if you do not want to use the makefile, you can run the command

gcc -c foo1.c foo2.c foo3.c

then

gcc -o output foo1.o foo2.o foo3.o

foo1.c

#include <stdio.h>
#include <string.h>

void funk1();

void funk1() {
    printf ("\nfunk1\n");
}


int main(void) {

    char *arg2;
    size_t nbytes = 100;

    while ( 1 ) {

        printf ("\nargv2 = %s\n" , arg2);
        printf ("\n:> ");
        getline (&arg2 , &nbytes , stdin);
        if( strcmp (arg2 , "1\n") == 0 ) {
            funk1 ();
        } else if( strcmp (arg2 , "2\n") == 0 ) {
            funk2 ();
        } else if( strcmp (arg2 , "3\n") == 0 ) {
            funk3 ();
        } else if( strcmp (arg2 , "4\n") == 0 ) {
            funk4 ();
        } else {
            funk5 ();
        }
    }
}

foo2.c

#include <stdio.h>
void funk2(){
    printf("\nfunk2\n");
}
void funk3(){
    printf("\nfunk3\n");
}

foo3.c

#include <stdio.h>

void funk4(){
    printf("\nfunk4\n");
}
void funk5(){
    printf("\nfunk5\n");
}

makefile

outputTest: foo1.o foo2.o foo3.o
    gcc -o output foo1.o foo2.o foo3.o
    make removeO

outputTest.o: foo1.c foo2.c foo3.c
    gcc -c foo1.c foo2.c foo3.c

clean:
    rm -f *.o output

removeO:
    rm -f *.o

changing kafka retention period during runtime

The correct config key is retention.ms

$ bin/kafka-topics.sh --zookeeper zk.prod.yoursite.com --alter --topic as-access --config retention.ms=86400000
Updated config for topic "my-topic".

Using Switch Statement to Handle Button Clicks

Hi its quite simple to make switch between buttons using switch case:-

 package com.example.browsebutton;


    import android.app.Activity;
    import android.os.Bundle;
    import android.view.View;
    import android.view.View.OnClickListener;
    import android.widget.Button;
    import android.widget.Toast;

        public class MainActivity extends Activity implements OnClickListener {
        Button b1,b2;
            @Override
            protected void onCreate(Bundle savedInstanceState) {
                super.onCreate(savedInstanceState);
                setContentView(R.layout.activity_main);
                b1=(Button)findViewById(R.id.button1);

                b2=(Button)findViewById(R.id.button2);
                b1.setOnClickListener(this);
                b2.setOnClickListener(this);
            }



            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub

                 int id=v.getId();
                 switch(id) {
                    case R.id.button1:
                  Toast.makeText(getBaseContext(), "btn1", Toast.LENGTH_LONG).show();
                //Your Operation

                  break;

                    case R.id.button2:
                          Toast.makeText(getBaseContext(), "btn2", Toast.LENGTH_LONG).show();


                          //Your Operation
                          break;
            }

        }}

How to use string.substr() function?

Possible solution without using substr()

#include<iostream>
#include<string>

using namespace std;


int main() {
    string c="12345";
    int p=0;

    for(int i=0;i<c.length();i++) {
        cout<<c[i];
        p++;

        if (p % 2 == 0 && i != c.length()-1) {
            cout<<" "<<c[i];
            p++;
        }
    }
}

How to set Navigation Drawer to be opened from right to left

I have solved this problem by changing the gravity of the navigationview

android:layout_gravity

to end instead of start

<android.support.design.widget.NavigationView
        android:id="@+id/nav_view"
        android:layout_width="wrap_content"
        android:layout_height="match_parent"
        android:layout_gravity="end"
        android:fitsSystemWindows="true"
        app:headerLayout="@layout/nav_header"
        app:menu="@menu/activity_drawer" />

It worked for me.

How to hide the keyboard when I press return key in a UITextField?

set delegate of UITextField, and over ride, textFieldShouldReturn method, in that method just write following two lines:

[textField resignFirstResponder];
return YES;

that's it. Before writing a code dont forget to set delegate of a UITextField and set Return key type to "Done" from properties window.(command + shift + I).

Is it possible only to declare a variable without assigning any value in Python?

I usually initialize the variable to something that denotes the type like

var = ""

or

var = 0

If it is going to be an object then don't initialize it until you instantiate it:

var = Var()

Finding partial text in range, return an index

I just found this when googling to solve the same problem, and had to make a minor change to the solution to make it work in my situation, as I had 2 similar substrings, "Sun" and "Sunstruck" to search for. The offered solution was locating the wrong entry when searching for "Sun". Data in column B

I added another column C, formulaes C1=" "&B1&" " and changed the search to =COUNTIF(B1:B10,"* "&A1&" *")>0, the extra column to allow finding the first of last entry in the concatenated string.

Logical operators ("and", "or") in DOS batch

Try the negation operand - 'not'!

Well, if you can perform 'AND' operation on an if statement using nested 'if's (refer previous answers), then you can do the same thing with 'if not' to perform an 'or' operation.

If you haven't got the idea quite as yet, read on. Otherwise, just don't waste your time and get back to programming.

Just as nested 'if's are satisfied only when all conditions are true, nested 'if not's are satisfied only when all conditions are false. This is similar to what you want to do with an 'or' operand, isn't it?

Even when any one of the conditions in the nested 'if not' is true, the whole statement remains non-satisfied. Hence, you can use negated 'if's in succession by remembering that the body of the condition statement should be what you wanna do if all your nested conditions are false. The body that you actually wanted to give should come under the else statement.

And if you still didn't get the jist of the thing, sorry, I'm 16 and that's the best I can do to explain.

In R, how to find the standard error of the mean?

y <- mean(x, na.rm=TRUE)

sd(y) for standard deviation var(y) for variance.

Both derivations use n-1 in the denominator so they are based on sample data.

How to select and change value of table cell with jQuery?

$("td:contains('c')").html("new");

or, more precisely $("#table_headers td:contains('c')").html("new");

and maybe for reuse you could create a function to call

function ReplaceCellContent(find, replace)
{
    $("#table_headers td:contains('" + find + "')").html(replace);
}

How to find and replace string?

Not exactly that, but std::string has many replace overloaded functions.

Go through this link to see explanation of each, with examples as to how they're used.

Also, there are several versions of string::find functions (listed below) which you can use in conjunction with string::replace.

  • find
  • rfind
  • find_first_of
  • find_last_of
  • find_first_not_of
  • find_last_not_of

Also, note that there are several versions of replace functions available from <algorithm> which you can also use (instead of string::replace):

  • replace
  • replace_if
  • replace_copy
  • replace_copy_if

How to apply a low-pass or high-pass filter to an array in Matlab?

You can design a lowpass Butterworth filter in runtime, using butter() function, and then apply that to the signal.

fc = 300; % Cut off frequency
fs = 1000; % Sampling rate

[b,a] = butter(6,fc/(fs/2)); % Butterworth filter of order 6
x = filter(b,a,signal); % Will be the filtered signal

Highpass and bandpass filters are also possible with this method. See https://www.mathworks.com/help/signal/ref/butter.html

Are nested try/except blocks in Python a good programming practice?

While in Java it's indeed a bad practice to use exceptions for flow control (mainly because exceptions force the JVM to gather resources (more here)), in Python you have two important principles: duck typing and EAFP. This basically means that you are encouraged to try using an object the way you think it would work, and handle when things are not like that.

In summary, the only problem would be your code getting too much indented. If you feel like it, try to simplify some of the nestings, like lqc suggested in the suggested answer above.

How to take screenshot of a div with JavaScript?

<script src="/assets/backend/js/html2canvas.min.js"></script>


<script>
    $("#download").on('click', function(){
        html2canvas($("#printform"), {
            onrendered: function (canvas) {
                var url = canvas.toDataURL();

                var triggerDownload = $("<a>").attr("href", url).attr("download", getNowFormatDate()+"????????.jpeg").appendTo("body");
                triggerDownload[0].click();
                triggerDownload.remove();
            }
        });
    })
</script>

quotation

Python: IndexError: list index out of range

I think you mean to put the rolling of the random a,b,c, etc within the loop:

a = None # initialise
while not (a in winning_numbers):
    # keep rolling an a until you get one not in winning_numbers
    a = random.randint(1,30)
    winning_numbers.append(a)

Otherwise, a will be generated just once, and if it is in winning_numbers already, it won't be added. Since the generation of a is outside the while (in your code), if a is already in winning_numbers then too bad, it won't be re-rolled, and you'll have one less winning number.

That could be what causes your error in if guess[i] == winning_numbers[i]. (Your winning_numbers isn't always of length 5).

Razor/CSHTML - Any Benefit over what we have?

  1. Everything is encoded by default!!! This is pretty huge.

  2. Declarative helpers can be compiled so you don't need to do anything special to share them. I think they will replace .ascx controls to some extent. You have to jump through some hoops to use an .ascx control in another project.

  3. You can make a section required which is nice.

"cannot be used as a function error"

Your compiler is right. You can't use the growthRate variable you declared in main as a function.

Maybe you should pick different names for your variables so they don't override function names?

How to determine if .NET Core is installed

Using Powershell:

Runtimes:

(dir (Get-Command dotnet).Path.Replace('dotnet.exe', 'shared\Microsoft.NETCore.App')).Name

SDKs:

(dir (Get-Command dotnet).Path.Replace('dotnet.exe', 'sdk')).Name

Reading data from XML

as per @Jon Skeet 's comment, you should use a XmlReader only if your file is very big. Here's how to use it. Assuming you have a Book class

public class Book {
    public string Title {get; set;}
    public string Author {get; set;}
}

you can read the XML file line by line with a small memory footprint, like this:

public static class XmlHelper {
    public static IEnumerable<Book> StreamBooks(string uri) {
        using (XmlReader reader = XmlReader.Create(uri)) {
            string title = null;
            string author = null;

            reader.MoveToContent();
            while (reader.Read()) {
                if (reader.NodeType == XmlNodeType.Element
                    && reader.Name == "Book") {
                    while (reader.Read()) {
                        if (reader.NodeType == XmlNodeType.Element &&
                            reader.Name == "Title") {
                            title = reader.ReadString();
                            break;
                        }
                    }
                    while (reader.Read()) {
                        if (reader.NodeType == XmlNodeType.Element &&
                            reader.Name == "Author") {
                            author =reader.ReadString();
                            break;
                        }
                    }
                    yield return new Book() {Title = title, Author = author};
                }
            }       
        }
    }

Example of usage:

string uri = @"c:\test.xml"; // your big XML file

foreach (var book in XmlHelper.StreamBooks(uri)) {
    Console.WriteLine("Title, Author: {0}, {1}", book.Title, book.Author);  
}

Datatables on-the-fly resizing

The code below is the combination of Chintan Panchal's answer along with Antoine Leclair's comment (placing the code in the windows resize event). (I didn't need the debounce mentioned by Antoine Leclair, however that could be a best practice.)

  $(window).resize( function() {
      $("#example").DataTable().columns.adjust().draw();
  });

This was the approach that worked in my case.

Allowing the "Enter" key to press the submit button, as opposed to only using MouseClick

 switch(KEYEVENT.getKeyCode()){
      case KeyEvent.VK_ENTER:
           // I was trying to use case 13 from the ascii table.
           //Krewn Generated method stub... 
           break;
 }

String Padding in C

Oh okay, makes sense. So I did this:

    char foo[10] = "hello";
    char padded[16];
    strcpy(padded, foo);
    printf("%s", StringPadRight(padded, 15, " "));

Thanks!

Do I cast the result of malloc?

In the C language, a void pointer can be assigned to any pointer, which is why you should not use a type cast. If you want "type safe" allocation, I can recommend the following macro functions, which I always use in my C projects:

#include <stdlib.h>
#define NEW_ARRAY(ptr, n) (ptr) = malloc((n) * sizeof *(ptr))
#define NEW(ptr) NEW_ARRAY((ptr), 1)

With these in place you can simply say

NEW_ARRAY(sieve, length);

For non-dynamic arrays, the third must-have function macro is

#define LEN(arr) (sizeof (arr) / sizeof (arr)[0])

which makes array loops safer and more convenient:

int i, a[100];

for (i = 0; i < LEN(a); i++) {
   ...
}

I have Python on my Ubuntu system, but gcc can't find Python.h

I found the answer in ubuntuforums (ubuntuforums), you can just add this to your gcc '$(python-config --includes)'

gcc $(python-config --includes) urfile.c

How do I create a timer in WPF?

In WPF, you use a DispatcherTimer.

System.Windows.Threading.DispatcherTimer dispatcherTimer = new System.Windows.Threading.DispatcherTimer();
dispatcherTimer.Tick += new EventHandler(dispatcherTimer_Tick);
dispatcherTimer.Interval = new TimeSpan(0,5,0);
dispatcherTimer.Start();


private void dispatcherTimer_Tick(object sender, EventArgs e)
{
  // code goes here
}

How to access the local Django webserver from outside world

install ngrok in terminal

sudo apt-get install -y ngrok-client

after that run:

ngrok http 8000
or 
ngrok http example.com:9000 

Java word count program

My implementation, not using StringTokenizer:

Map<String, Long> getWordCounts(List<String> sentences, int maxLength) {
    Map<String, Long> commonWordsInEventDescriptions = sentences
        .parallelStream()
        .map(sentence -> sentence.replace(".", ""))
        .map(string -> string.split(" "))
        .flatMap(Arrays::stream)
        .map(s -> s.toLowerCase())
        .filter(word -> word.length() >= 2 && word.length() <= maxLength)
        .collect(groupingBy(Function.identity(), counting()));
    }

Then, you could call it like this, as an example:

getWordCounts(list, 9).entrySet().stream()
                .filter(pair -> pair.getValue() <= 3 && pair.getValue() >= 1)
                .findFirst()
                .orElseThrow(() -> 
    new RuntimeException("No matching word found.")).getKey();

Perhaps flipping the method to return Map<Long, String> might be better.

Subtract 1 day with PHP

Answear taken from Php manual strtotime function comments :

echo date( "Y-m-d", strtotime( "2009-01-31 -1 day"));

Or

$date = "2009-01-31";
echo date( "Y-m-d", strtotime( $date . "-1 day"));

static constructors in C++? I need to initialize private static objects

Is this a solution?

class Foo
{
public:
    size_t count;
    Foo()
    {
        static size_t count = 0;
        this->count = count += 1;
    }
};

Eclipse: Java was started but returned error code=13

This error occurs because your Eclipse version is 64-bit. You should download and install 64-bit JRE and add the path to it in eclipse.ini. For example:

...
--launcher.appendVmargs
-vm
C:\Program Files\Java\jre1.8.0_45\bin\javaw.exe
-vmargs
...

Note: The -vm parameter should be just before -vmargs and the path should be on a separate line. It should be the full path to the javaw.exe file. Do not enclose the path in double quotes (").

If your Eclipse is 32-bit, install a 32-bit JRE and use the path to its javaw.exe file.

Twitter Bootstrap 3.0 how do I "badge badge-important" now

Well, this is a terribly late answer but I think I'll still put my two cents in... I could have posted this as a comment because this answer doesn't essentially add any new solution but it does add value to the post as yet another alternative. But in a comment I wouldn't be able to give all the details because of character limit.

NOTE: This needs an edit to bootstrap CSS file - move style definitions for .badge above .label-default. Couldn't find any practical side effects due to the change in my limited testing.

While broc.seib's solution is probably the best way to achieve the requirement of OP with minimal addition to CSS, it is possible to achieve the same effect without any extra CSS at all just like Jens A. Koch's solution or by using .label-xxx contextual classes because they are easy to remember compared to progress-bar-xxx classes. I don't think that .alert-xxx classes give the same effect.

All you have to do is just use .badge and .label-xxx classes together (but in this order). Don't forget to make the changes mentioned in NOTE above.

<a href="#">Inbox <span class="badge label-warning">42</span></a> looks like this:

Badge with warning bg

IMPORTANT: This solution may break your styles if you decide to upgrade and forget to make the changes in your new local CSS file. My solution for this challenge was to copy all .label-xxx styles in my custom CSS file and load it after all other CSS files. This approach also helps when I use a CDN for loading BS3.

**P.S: ** Both the top rated answers have their pros and cons. It's just the way you prefer to do your CSS because there is no "only correct way" to do it.

An error occurred while updating the entries. See the inner exception for details

Click "View Detail..." a window will open where you can expand the "Inner Exception" my guess is that when you try to delete the record there is a reference constraint violation. The inner exception will give you more information on that so you can modify your code to remove any references prior to deleting the record.

enter image description here

Take nth column in a text file

For the sake of completeness:

while read _ _ one _ two _; do
    echo "$one $two"
done < file.txt

Instead of _ an arbitrary variable (such as junk) can be used as well. The point is just to extract the columns.

Demo:

$ while read _ _ one _ two _; do echo "$one $two"; done < /tmp/file.txt
1657 19.6117
1410 18.8302
3078 18.6695
2434 14.0508
3129 13.5495

How can I send an HTTP POST request to a server from Excel using VBA?

To complete the response of the other users:

For this I have created an "WinHttp.WinHttpRequest.5.1" object.

Send a post request with some data from Excel using VBA:

Dim LoginRequest As Object
Set LoginRequest = CreateObject("WinHttp.WinHttpRequest.5.1")
LoginRequest.Open "POST", "http://...", False
LoginRequest.setRequestHeader "Content-type", "application/x-www-form-urlencoded"
LoginRequest.send ("key1=value1&key2=value2")

Send a get request with token authentication from Excel using VBA:

Dim TCRequestItem As Object
Set TCRequestItem = CreateObject("WinHttp.WinHttpRequest.5.1")
TCRequestItem.Open "GET", "http://...", False
TCRequestItem.setRequestHeader "Content-Type", "application/xml"
TCRequestItem.setRequestHeader "Accept", "application/xml"
TCRequestItem.setRequestHeader "Authorization", "Bearer " & token
TCRequestItem.send

Why am I getting InputMismatchException?

Since you have the manual user input loop, after the scanner has read your first input it will pass the carriage/return into the next line which will also be read; of course, that is not what you wanted.

You can try this

try {
    // ...
} catch (InputMismatchException e) {
    reader.next(); 
}

or alternatively, you can consume that carriage return before reading your next double input by calling

reader.next()

How to zip a whole folder using PHP

I did some small improvement in the script.

  <?php
    $directory = "./";
    //create zip object
    $zip = new ZipArchive();
    $zip_name = time().".zip";
    $zip->open($zip_name,  ZipArchive::CREATE);
    $files = new RecursiveIteratorIterator(
        new RecursiveDirectoryIterator($directory),
        RecursiveIteratorIterator::LEAVES_ONLY
    );
    foreach ($files as $file) {
        $path = $file->getRealPath();
        //check file permission
        if(fileperms($path)!="16895"){
            $zip->addFromString(basename($path),  file_get_contents($path)) ;
            echo "<span style='color:green;'>{$path} is added to zip file.<br /></span> " ;
        }
        else{
            echo"<span style='color:red;'>{$path} location could not be added to zip<br /></span>";
        }
    }
    $zip->close();
    ?>

Passing html values into javascript functions

Try: if(parseInt(order)>0){....

Is it bad to have my virtualenv directory inside my git repository?

If you know which operating systems your application will be running on, I would create one virtualenv for each system and include it in my repository. Then I would make my application detect which system it is running on and use the corresponding virtualenv.

The system could e.g. be identified using the platform module.

In fact, this is what I do with an in-house application I have written, and to which I can quickly add a new system's virtualenv in case it is needed. This way, I do not have to rely on that pip will be able to successfully download the software my application requires. I will also not have to worry about compilation of e.g. psycopg2 which I use.

If you do not know which operating system your application may run on, you are probably better off using pip freeze as suggested in other answers here.

How do I install Keras and Theano in Anaconda Python on Windows?

Anaconda with Windows

  • Run anaconda prompt with administrator privilages
  • conda update conda
  • conda update --all
  • conda install mingw libpython
  • conda install theano

After conda commands it's required to accept process - Proceed ([y]/n)?

ASP.NET MVC Ajax Error handling

After googling I write a simple Exception handing based on MVC Action Filter:

public class HandleExceptionAttribute : HandleErrorAttribute
{
    public override void OnException(ExceptionContext filterContext)
    {
        if (filterContext.HttpContext.Request.IsAjaxRequest() && filterContext.Exception != null)
        {
            filterContext.HttpContext.Response.StatusCode = (int)HttpStatusCode.InternalServerError;
            filterContext.Result = new JsonResult
            {
                JsonRequestBehavior = JsonRequestBehavior.AllowGet,
                Data = new
                {
                    filterContext.Exception.Message,
                    filterContext.Exception.StackTrace
                }
            };
            filterContext.ExceptionHandled = true;
        }
        else
        {
            base.OnException(filterContext);
        }
    }
}

and write in global.ascx:

 public static void RegisterGlobalFilters(GlobalFilterCollection filters)
 {
      filters.Add(new HandleExceptionAttribute());
 }

and then write this script on the layout or Master page:

<script type="text/javascript">
      $(document).ajaxError(function (e, jqxhr, settings, exception) {
                       e.stopPropagation();
                       if (jqxhr != null)
                           alert(jqxhr.responseText);
                     });
</script>

Finally you should turn on custom error. and then enjoy it :)

How I can get web page's content and save it into the string variable

You can use the WebClient

Using System.Net;
    
WebClient client = new WebClient();
string downloadString = client.DownloadString("http://www.gooogle.com");

How to run a script as root on Mac OS X?

In order for sudo to work the way everyone suggest, you need to be in the admin group.

Does document.body.innerHTML = "" clear the web page?

I clear my screen using is function that

var clear_body = function (){
    var lista = document.body.childNodes;
    for (var i = lista.length - 1; i >= 0 ;i--){
        document.body.removeChild(lista[i])
    }
}

Warning message: In `...` : invalid factor level, NA generated

Here is a flexible approach, it can be used in all cases, in particular:

  1. to affect only one column, or
  2. the dataframe has been obtained from applying previous operations (e.g. not immediately opening a file, or creating a new data frame).

First, un-factorize a string using the as.character function, and, then, re-factorize with the as.factor (or simply factor) function:

fixed <- data.frame("Type" = character(3), "Amount" = numeric(3))

# Un-factorize (as.numeric can be use for numeric values)
#              (as.vector  can be use for objects - not tested)
fixed$Type <- as.character(fixed$Type)
fixed[1, ] <- c("lunch", 100)

# Re-factorize with the as.factor function or simple factor(fixed$Type)
fixed$Type <- as.factor(fixed$Type)

How to create a private class method?

I too, find Ruby (or at least my knowledge of it) short of the mark in this area. For instance the following does what I want but is clumsy,

class Frob
    attr_reader :val1, :val2

    Tolerance = 2 * Float::EPSILON

    def initialize(val1, val2)
        @val2 = val1
        @val2 = val2
        ...
    end

    # Stuff that's likely to change and I don't want part
    # of a public API.  Furthermore, the method is operating
    # solely upon 'reference' and 'under_test' and will be flagged as having
    # low cohesion by quality metrics unless made a class method.
    def self.compare(reference, under_test)
        # special floating point comparison
        (reference - under_test).abs <= Tolerance
    end
    private_class_method :compare

    def ==(arg)
        self.class.send(:compare, val1, arg.val1) &&
        self.class.send(:compare, val2, arg.val2) &&
        ...
    end
end

My problems with the code above is that the Ruby syntax requirements and my code quality metrics conspire to made for cumbersome code. To have the code both work as I want and to quiet the metrics, I must make compare() a class method. Since I don't want it to be part of the class' public API, I need it to be private, yet 'private' by itself does not work. Instead I am force to use 'private_class_method' or some such work-around. This, in turn, forces the use of 'self.class.send(:compare...' for each variable I test in '==()'. Now that's a bit unwieldy.

string in namespace std does not name a type

You need to

#include <string>

<iostream> declares cout, cin, not string.

How to start new line with space for next line in Html.fromHtml for text view in android

Did you try <br/>, <br><br/> or simply \n ? <br> should be supported according to this source, though.

Supported HTML tags

What are the differences between Deferred, Promise and Future in JavaScript?

A Promise represents a proxy for a value not necessarily known when the promise is created. It allows you to associate handlers to an asynchronous action's eventual success value or failure reason. This lets asynchronous methods return values like synchronous methods: instead of the final value, the asynchronous method returns a promise of having a value at some point in the future.

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise

The deferred.promise() method allows an asynchronous function to prevent other code from interfering with the progress or status of its internal request. The Promise exposes only the Deferred methods needed to attach additional handlers or determine the state (then, done, fail, always, pipe, progress, state and promise), but not ones that change the state (resolve, reject, notify, resolveWith, rejectWith, and notifyWith).

If target is provided, deferred.promise() will attach the methods onto it and then return this object rather than create a new one. This can be useful to attach the Promise behavior to an object that already exists.

If you are creating a Deferred, keep a reference to the Deferred so that it can be resolved or rejected at some point. Return only the Promise object via deferred.promise() so other code can register callbacks or inspect the current state.

Simply we can say that a Promise represents a value that is not yet known where as a Deferred represents work that is not yet finished.


enter image description here

Python csv string to array

Simple - the csv module works with lists, too:

>>> a=["1,2,3","4,5,6"]  # or a = "1,2,3\n4,5,6".split('\n')
>>> import csv
>>> x = csv.reader(a)
>>> list(x)
[['1', '2', '3'], ['4', '5', '6']]

Maven Installation OSX Error Unsupported major.minor version 51.0

Do this in your .profile -

export JAVA_HOME=`/usr/libexec/java_home`

(backticks make sure to execute the command and place its value in JAVA_HOME)

Sort a Map<Key, Value> by values

Best thing is to convert HashMap to TreeMap. TreeMap sort keys on its own. If you want to sort on values than quick fix can be you can switch values with keys if your values are not duplicates.

PHP MySQL Google Chart JSON - Complete Example

Some might encounter this error (I got it while implementing PHP-MySQLi-JSON-Google Chart Example):

You called the draw() method with the wrong type of data rather than a DataTable or DataView.

The solution would be: replace jsapi and just use loader.js with:

google.charts.load('current', {packages: ['corechart']}) and 
google.charts.setOnLoadCallback 

-- according to the release notes --> The version of Google Charts that remains available via the jsapi loader is no longer being updated consistently. Please use the new gstatic loader from now on.

Adding options to a <select> using jQuery?

That works well.

If adding more than one option element, I'd recommend performing the append once as opposed to performing an append on each element.

Error on line 2 at column 1: Extra content at the end of the document

The problem is database connection string, one of your MySQL database connection function parameter is not correct ,so there is an error message in the browser output, Just right click output webpage and view html source code you will see error line followed by correct XML output data(file). I had same problem and the above solution worked perfectly.

How to get URL parameters with Javascript?

function getURLParameter(name) {
  return decodeURIComponent((new RegExp('[?|&]' + name + '=' + '([^&;]+?)(&|#|;|$)').exec(location.search) || [null, ''])[1].replace(/\+/g, '%20')) || null;
}

So you can use:

myvar = getURLParameter('myvar');

How can I get the "network" time, (from the "Automatic" setting called "Use network-provided values"), NOT the time on the phone?

This seemed to work for me:

LocationManager locMan = (LocationManager) activity.getSystemService(activity.LOCATION_SERVICE);
long networkTS = locMan.getLastKnownLocation(LocationManager.NETWORK_PROVIDER).getTime();

Working on Android 2.2 API (Level 8)

How to detect when keyboard is shown and hidden

You may just need addObserver in viewDidLoad. But having addObserver in viewWillAppear and removeObserver in viewWillDisappear prevents rare crashes which happens when you are changing your view.

Swift 4.2

override func viewWillAppear(_ animated: Bool) {
    super.viewWillAppear(animated)
    NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillDisappear), name: UIResponder.keyboardWillHideNotification, object: nil)
    NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillAppear), name: UIResponder.keyboardWillShowNotification, object: nil)
}

@objc func keyboardWillAppear() {
    //Do something here
}

@objc func keyboardWillDisappear() {
    //Do something here
}

override func viewWillDisappear(_ animated: Bool) {
    super.viewWillDisappear(animated)
    NotificationCenter.default.removeObserver(self)
}

Swift 3 and 4

override func viewWillAppear(_ animated: Bool) {
    super.viewWillAppear(animated)
    NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillDisappear), name: Notification.Name.UIKeyboardWillHide, object: nil)
    NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillAppear), name: Notification.Name.UIKeyboardWillShow, object: nil)
}

@objc func keyboardWillAppear() {
    //Do something here
}

@objc func keyboardWillDisappear() {
    //Do something here
}

override func viewWillDisappear(_ animated: Bool) {
    super.viewWillDisappear(animated)
    NotificationCenter.default.removeObserver(self)
}

Older Swift

override func viewWillAppear(animated: Bool) {
    super.viewWillAppear(animated)

    NSNotificationCenter.defaultCenter().addObserver(self, selector:"keyboardWillAppear:", name: UIKeyboardWillShowNotification, object: nil)
    NSNotificationCenter.defaultCenter().addObserver(self, selector:"keyboardWillDisappear:", name: UIKeyboardWillHideNotification, object: nil)
}

func keyboardWillAppear(notification: NSNotification){
    // Do something here
}

func keyboardWillDisappear(notification: NSNotification){
    // Do something here
}

override func viewWillDisappear(animated: Bool) {
    super.viewWillDisappear(animated)
    NSNotificationCenter.defaultCenter().removeObserver(self)
}

PHP decoding and encoding json with unicode characters

A hacky way of doing JSON_UNESCAPED_UNICODE in PHP 5.3. Really disappointed by PHP json support. Maybe this will help someone else.

$array = some_json();
// Encode all string children in the array to html entities.
array_walk_recursive($array, function(&$item, $key) {
    if(is_string($item)) {
        $item = htmlentities($item);
    }
});
$json = json_encode($array);

// Decode the html entities and end up with unicode again.
$json = html_entity_decode($rson);

how to save DOMPDF generated content to file?

I did test your code and the only problem I could see was the lack of permission given to the directory you try to write the file in to.

Give "write" permission to the directory you need to put the file. In your case it is the current directory.

Use "chmod" in linux.

Add "Everyone" with "write" enabled to the security tab of the directory if you are in Windows.

How to set min-height for bootstrap container

Usually, if you are using bootstrap you can do this to set a min-height of 100%.

 <div class="container-fluid min-vh-100"></div>

this will also solve the footer not sticking at the bottom.

you can also do this from CSS with the following class

.stickDamnFooter{min-height: 100vh;}

if this class does not stick your footer just add position: fixed; to that same css class and you will not have this issue in a lifetime. Cheers.

How to sort an ArrayList?

You can do like this:

List<String> yourList = new ArrayList<String>();
Collections.sort(yourList, Collections.reverseOrder());

Collection has a default Comparator that can help you with that.

Also, if you want to use some Java 8 new features, you can do like that:

List<String> yourList = new ArrayList<String>();
yourList = yourList.stream().sorted(Collections.reverseOrder()).collect(Collectors.toList());

How to merge two arrays in JavaScript and de-duplicate items

Using a Set (ECMAScript 2015), it will be as simple as that:

_x000D_
_x000D_
const array1 = ["Vijendra", "Singh"];_x000D_
const array2 = ["Singh", "Shakya"];_x000D_
console.log(Array.from(new Set(array1.concat(array2))));
_x000D_
_x000D_
_x000D_

The best way to remove duplicate values from NSMutableArray in Objective-C?

Here is the code of removing duplicates values from NSMutable Array..it will work for you. myArray is your Mutable Array that you want to remove duplicates values..

for(int j = 0; j < [myMutableArray count]; j++){
    for( k = j+1;k < [myMutableArray count];k++){
    NSString *str1 = [myMutableArray objectAtIndex:j];
    NSString *str2 = [myMutableArray objectAtIndex:k];
    if([str1 isEqualToString:str2])
        [myMutableArray removeObjectAtIndex:k];
    }
 } // Now print your array and will see there is no repeated value

Simplest way to do a recursive self-join?

Using CTEs you can do it this way

DECLARE @Table TABLE(
        PersonID INT,
        Initials VARCHAR(20),
        ParentID INT
)

INSERT INTO @Table SELECT     1,'CJ',NULL
INSERT INTO @Table SELECT     2,'EB',1
INSERT INTO @Table SELECT     3,'MB',1
INSERT INTO @Table SELECT     4,'SW',2
INSERT INTO @Table SELECT     5,'YT',NULL
INSERT INTO @Table SELECT     6,'IS',5

DECLARE @PersonID INT

SELECT @PersonID = 1

;WITH Selects AS (
        SELECT *
        FROM    @Table
        WHERE   PersonID = @PersonID
        UNION ALL
        SELECT  t.*
        FROM    @Table t INNER JOIN
                Selects s ON t.ParentID = s.PersonID
)
SELECT  *
FROm    Selects

Swift convert unix time to date and time

You can get a date with that value by using the NSDate(withTimeIntervalSince1970:) initializer:

let date = NSDate(timeIntervalSince1970: 1415637900)

How do I convert 2018-04-10T04:00:00.000Z string to DateTime?

Update: Using DateTimeFormat, introduced in java 8:

The idea is to define two formats: one for the input format, and one for the output format. Parse with the input formatter, then format with the output formatter.

Your input format looks quite standard, except the trailing Z. Anyway, let's deal with this: "yyyy-MM-dd'T'HH:mm:ss.SSS'Z'". The trailing 'Z' is the interesting part. Usually there's time zone data here, like -0700. So the pattern would be ...Z, i.e. without apostrophes.

The output format is way more simple: "dd-MM-yyyy". Mind the small y -s.

Here is the example code:

DateTimeFormatter inputFormatter = DateTimeFormatter.ofPattern("yyyy-MM-dd'T'HH:mm:ss.SSS'Z'", Locale.ENGLISH);
DateTimeFormatter outputFormatter = DateTimeFormatter.ofPattern("dd-MM-yyy", Locale.ENGLISH);
LocalDate date = LocalDate.parse("2018-04-10T04:00:00.000Z", inputFormatter);
String formattedDate = outputFormatter.format(date);
System.out.println(formattedDate); // prints 10-04-2018

Original answer - with old API SimpleDateFormat

SimpleDateFormat inputFormat = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSS'Z'");
SimpleDateFormat outputFormat = new SimpleDateFormat("dd-MM-yyyy");
Date date = inputFormat.parse("2018-04-10T04:00:00.000Z");
String formattedDate = outputFormat.format(date);
System.out.println(formattedDate); // prints 10-04-2018

Add key value pair to all objects in array

You can do this with map()

_x000D_
_x000D_
var arrOfObj = [{_x000D_
  name: 'eve'_x000D_
}, {_x000D_
  name: 'john'_x000D_
}, {_x000D_
  name: 'jane'_x000D_
}];_x000D_
_x000D_
var result = arrOfObj.map(function(o) {_x000D_
  o.isActive = true;_x000D_
  return o;_x000D_
})_x000D_
_x000D_
console.log(result)
_x000D_
_x000D_
_x000D_

If you want to keep original array you can clone objects with Object.assign()

_x000D_
_x000D_
var arrOfObj = [{_x000D_
  name: 'eve'_x000D_
}, {_x000D_
  name: 'john'_x000D_
}, {_x000D_
  name: 'jane'_x000D_
}];_x000D_
_x000D_
var result = arrOfObj.map(function(el) {_x000D_
  var o = Object.assign({}, el);_x000D_
  o.isActive = true;_x000D_
  return o;_x000D_
})_x000D_
_x000D_
console.log(arrOfObj);_x000D_
console.log(result);
_x000D_
_x000D_
_x000D_

Adding a newline character within a cell (CSV)

I have the same issue, when I try to export the content of email to csv and still keep it break line when importing to excel.

I export the conent as this: ="Line 1"&CHAR(10)&"Line 2"

When I import it to excel(google), excel understand it as string. It still not break new line.

We need to trigger excel to treat it as formula by: Format -> Number | Scientific.

This is not the good way but it resolve my issue.

C# difference between == and Equals()

Really great answers and examples!

I would just like to add the fundamental difference between the two,

Operators such as == are not polymorphic, while Equals is

With that concept in mind, if you work out any example (by looking at left hand and right hand reference type, and checking/knowing if the type actually has == operator overloaded and Equals being overriden) you are certain to get the right answer.

ValidateAntiForgeryToken purpose, explanation and example

The basic purpose of ValidateAntiForgeryToken attribute is to prevent cross-site request forgery attacks.

A cross-site request forgery is an attack in which a harmful script element, malicious command, or code is sent from the browser of a trusted user. For more information on this please visit http://www.asp.net/mvc/overview/security/xsrfcsrf-prevention-in-aspnet-mvc-and-web-pages.

It is simple to use, you need to decorate method with ValidateAntiForgeryToken attribute as below:

[HttpPost]  
[ValidateAntiForgeryToken]  
public ActionResult CreateProduct(Product product)  
{
  if (ModelState.IsValid)  
  {
    //your logic 
  }
  return View(ModelName);
}

It is derived from System.Web.Mvc namespace.

And in your view, add this code to add the token so it is used to validate the form upon submission.

@Html.AntiForgeryToken()

Docker remove <none> TAG images

Its simple and clear,

Even I took 3 days to understand this simple and crisp error.

The docker image is not built successfully

Step 7/13 : COPY jupyter_notebook_config.py /root/.jupyter/
 ---> bf29ce6fe6dc
Step 8/13 : COPY notebooks /notebooks
COPY failed: stat /var/lib/docker/tmp/docker-builder776981166/notebooks: no such file or directory
anarchist@anarchist-desktop:~/Documents/sam/dockerDem$ docker images
REPOSITORY          TAG                 IMAGE ID            CREATED             SIZE
<none>              <none>              bf29ce6fe6dc        9 seconds ago       1.27GB
ubuntu              16.04               a51debf7e1eb        3 weeks ago         116MB

Then I removed the 8th line from Dockerfile, it was signal success this time.

Successfully built b6724370f8ca
Successfully tagged dem:expo
anarchist@anarchist-desktop:~/Documents/sam/dockerDem$ docker run -it -p 8888:8888 dem:expo
[I 06:11:38.984 NotebookApp] Writing notebook server cookie secret to /root/.local/share/jupyter/runtime/notebook_cookie_secret
[I 06:11:39.011 NotebookApp] Serving notebooks from local directory: /
[I 06:11:39.011 NotebookApp] The Jupyter Notebook is running at:
[I 06:11:39.011 NotebookApp] http://(296d81166725 or 127.0.0.1):8888/?token=496feb282ef749c05277ef57a51e8a56fedb1c6b337b9f92

It says successfully tagged dem:expo, this line is imp during docker process.