Programs & Examples On #Testcomplete

TestComplete is a functional automated testing platform developed by SmartBear Software. TestComplete gives testers the ability to create automated tests for Microsoft Windows, Web, Android (operating system), and iOS applications.

Removing whitespace between HTML elements when using line breaks

Sorry if this is old but I just found a solution.

Try setting the font-size to 0. Thus the white-spaces in between the images will be 0 in width, and the images won't be affected.

Don't know if this works in all browsers, but I tried it with Chromium and some <li> elements with display: inline-block;.

Is a URL allowed to contain a space?

As per RFC 1738:

Unsafe:

Characters can be unsafe for a number of reasons. The space character is unsafe because significant spaces may disappear and insignificant spaces may be introduced when URLs are transcribed or typeset or subjected to the treatment of word-processing programs. The characters "<" and ">" are unsafe because they are used as the delimiters around URLs in free text; the quote mark (""") is used to delimit URLs in some systems. The character "#" is unsafe and should always be encoded because it is used in World Wide Web and in other systems to delimit a URL from a fragment/anchor identifier that might follow it. The character "%" is unsafe because it is used for encodings of other characters. Other characters are unsafe because gateways and other transport agents are known to sometimes modify such characters. These characters are "{", "}", "|", "\", "^", "~", "[", "]", and "`".

All unsafe characters must always be encoded within a URL. For example, the character "#" must be encoded within URLs even in systems that do not normally deal with fragment or anchor identifiers, so that if the URL is copied into another system that does use them, it will not be necessary to change the URL encoding.

Python Pandas : pivot table with aggfunc = count unique distinct

Do you mean something like this?

In [39]: df2.pivot_table(values='X', rows='Y', cols='Z', 
                         aggfunc=lambda x: len(x.unique()))
Out[39]: 
Z   Z1  Z2  Z3
Y             
Y1   1   1 NaN
Y2 NaN NaN   1

Note that using len assumes you don't have NAs in your DataFrame. You can do x.value_counts().count() or len(x.dropna().unique()) otherwise.

How can I get the count of line in a file in an efficient way?

Old post, but I have a solution that could be usefull for next people. Why not just use file length to know what is the progression? Of course, lines has to be almost the same size, but it works very well for big files:

public static void main(String[] args) throws IOException {
    File file = new File("yourfilehere");
    double fileSize = file.length();
    System.out.println("=======> File size = " + fileSize);
    InputStream inputStream = new FileInputStream(file);
    InputStreamReader inputStreamReader = new InputStreamReader(inputStream, "iso-8859-1");
    BufferedReader bufferedReader = new BufferedReader(inputStreamReader);
    int totalRead = 0;
    try {
        while (bufferedReader.ready()) {
            String line = bufferedReader.readLine();
            // LINE PROCESSING HERE
            totalRead += line.length() + 1; // we add +1 byte for the newline char.
            System.out.println("Progress ===> " + ((totalRead / fileSize) * 100) + " %");
        }
    } finally {
        bufferedReader.close();
    }
}

It allows to see the progression without doing any full read on the file. I know it depends on lot of elements, but I hope it will be usefull :).

[Edition] Here is a version with estimated time. I put some SYSO to show progress and estimation. I see that you have a good time estimation errors after you have treated enough line (I try with 10M lines, and after 1% of the treatment, the time estimation was exact at 95%). I know, some values has to be set in variable. This code is quickly written but has be usefull for me. Hope it will be for you too :).

long startProcessLine = System.currentTimeMillis();
    int totalRead = 0;
    long progressTime = 0;
    double percent = 0;
    int i = 0;
    int j = 0;
    int fullEstimation = 0;
    try {
        while (bufferedReader.ready()) {
            String line = bufferedReader.readLine();
            totalRead += line.length() + 1;
            progressTime = System.currentTimeMillis() - startProcessLine;
            percent = (double) totalRead / fileSize * 100;
            if ((percent > 1) && i % 10000 == 0) {
                int estimation = (int) ((progressTime / percent) * (100 - percent));
                fullEstimation += progressTime + estimation;
                j++;
                System.out.print("Progress ===> " + percent + " %");
                System.out.print(" - current progress : " + (progressTime) + " milliseconds");
                System.out.print(" - Will be finished in ===> " + estimation + " milliseconds");
                System.out.println(" - estimated full time => " + (progressTime + estimation));
            }
            i++;
        }
    } finally {
        bufferedReader.close();
    }
    System.out.println("Ended in " + (progressTime) + " seconds");
    System.out.println("Estimative average ===> " + (fullEstimation / j));
    System.out.println("Difference: " + ((((double) 100 / (double) progressTime)) * (progressTime - (fullEstimation / j))) + "%");

Feel free to improve this code if you think it's a good solution.

How can I convert JSON to CSV?

My simple way to solve this:

Create a new Python file like: json_to_csv.py

Add this code:

import csv, json, sys
#if you are not using utf-8 files, remove the next line
sys.setdefaultencoding("UTF-8")
#check if you pass the input file and output file
if sys.argv[1] is not None and sys.argv[2] is not None:

    fileInput = sys.argv[1]
    fileOutput = sys.argv[2]

    inputFile = open(fileInput)
    outputFile = open(fileOutput, 'w')
    data = json.load(inputFile)
    inputFile.close()

    output = csv.writer(outputFile)

    output.writerow(data[0].keys())  # header row

    for row in data:
        output.writerow(row.values())

After add this code, save the file and run at the terminal:

python json_to_csv.py input.txt output.csv

I hope this help you.

SEEYA!

"Content is not allowed in prolog" when parsing perfectly valid XML on GAE

In my xml file, the header looked like this:

<?xml version="1.0" encoding="utf-16"? />

In a test file, I was reading the file bytes and decoding the data as UTF-8 (not realizing the header in this file was utf-16) to create a string.

byte[] data = Files.readAllBytes(Paths.get(path));
String dataString = new String(data, "UTF-8");

When I tried to deserialize this string into an object, I was seeing the same error:

javax.xml.stream.XMLStreamException: ParseError at [row,col]:[1,1]
Message: Content is not allowed in prolog.

When I updated the second line to

String dataString = new String(data, "UTF-16");

I was able to deserialize the object just fine. So as Romain had noted above, the encodings need to match.

Javascript array search and remove string?

I'm actually updating this thread with a more recent 1-line solution:

let arr = ['A', 'B', 'C'];
arr = arr.filter(e => e !== 'B'); // will return ['A', 'C']

The idea is basically to filter the array by selecting all elements different to the element you want to remove.

Note: will remove all occurrences.

EDIT:

If you want to remove only the first occurence:

t = ['A', 'B', 'C', 'B'];
t.splice(t.indexOf('B'), 1); // will return ['B'] and t is now equal to ['A', 'C', 'B']

Finding duplicate values in MySQL

One very late contribution... in case it helps anyone waaaaaay down the line... I had a task to find matching pairs of transactions (actually both sides of account-to-account transfers) in a banking app, to identify which ones were the 'from' and 'to' for each inter-account-transfer transaction, so we ended up with this:

SELECT 
    LEAST(primaryid, secondaryid) AS transactionid1,
    GREATEST(primaryid, secondaryid) AS transactionid2
FROM (
    SELECT table1.transactionid AS primaryid, 
        table2.transactionid AS secondaryid
    FROM financial_transactions table1
    INNER JOIN financial_transactions table2 
    ON table1.accountid = table2.accountid
    AND table1.transactionid <> table2.transactionid 
    AND table1.transactiondate = table2.transactiondate
    AND table1.sourceref = table2.destinationref
    AND table1.amount = (0 - table2.amount)
) AS DuplicateResultsTable
GROUP BY transactionid1
ORDER BY transactionid1;

The result is that the DuplicateResultsTable provides rows containing matching (i.e. duplicate) transactions, but it also provides the same transaction id's in reverse the second time it matches the same pair, so the outer SELECT is there to group by the first transaction ID, which is done by using LEAST and GREATEST to make sure the two transactionid's are always in the same order in the results, which makes it safe to GROUP by the first one, thus eliminating all the duplicate matches. Ran through nearly a million records and identified 12,000+ matches in just under 2 seconds. Of course the transactionid is the primary index, which really helped.

Oracle: SQL query that returns rows with only numeric values

The complete list of the regexp_like and other regexp functions in Oracle 11.1:

http://66.221.222.85/reference/regexp.html

In your example:

SELECT X
FROM test
WHERE REGEXP_LIKE(X, '^[[:digit:]]$');

What is the difference between Google App Engine and Google Compute Engine?

App Engine is a Platform-as-a-Service. It means that you simply deploy your code, and the platform does everything else for you. For example, if your app becomes very successful, App Engine will automatically create more instances to handle the increased volume.

Read more about App Engine

Compute Engine is an Infrastructure-as-a-Service. You have to create and configure your own virtual machine instances. It gives you more flexibility and generally costs much less than App Engine. The drawback is that you have to manage your app and virtual machines yourself.

Read more about Compute Engine

You can mix both App Engine and Compute Engine, if necessary. They both work well with the other parts of the Google Cloud Platform.

EDIT (May 2016):

One more important distinction: projects running on App Engine can scale down to zero instances if no requests are coming in. This is extremely useful at the development stage as you can go for weeks without going over the generous free quota of instance-hours. Flexible runtime (i.e. "managed VMs") require at least one instance to run constantly.

EDIT (April 2017):

Cloud Functions (currently in beta) is the next level up from App Engine in terms of abstraction - no instances! It allows developers to deploy bite-size pieces of code that execute in response to different events, which may include HTTP requests, changes in Cloud Storage, etc.

The biggest difference with App Engine is that functions are priced per 100 milliseconds, while App Engine's instances shut down only after 15 minutes of inactivity. Another advantage is that Cloud Functions execute immediately, while a call to App Engine may require a new instance - and cold-starting a new instance may take a few seconds or longer (depending on runtime and your code).

This makes Cloud Functions ideal for (a) rare calls - no need to keep an instance live just in case something happens, (b) rapidly changing loads where instances are often spinning and shutting down, and possibly more use cases.

Read more about Cloud Functions

android button selector

You can't achieve text size change with a state list drawable. To change text color and text size do this:

Text color

To change the text color, you can create color state list resource. It will be a separate resource located in res/color/ directory. In layout xml you have to set it as the value for android:textColor attribute. The color selector will then contain something like this:

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:state_pressed="true" android:color="@color/text_pressed" />
    <item android:color="@color/text_normal" />
</selector>

Text size

You can't change the size of the text simply with resources. There's no "dimen selector". You have to do it in code. And there is no straightforward solution.

Probably the easiest solution might be utilizing View.onTouchListener() and handle the up and down events accordingly. Use something like this:

view.setOnTouchListener(new OnTouchListener() {

        @Override
        public boolean onTouch(View v, MotionEvent event) {
            switch (event.getAction()) {
            case MotionEvent.ACTION_DOWN:
                // change text size to the "pressed value"
                return true;
            case MotionEvent.ACTION_UP:
                // change text size to the "normal value"
                return true;
            default:
                return false;
            }
        }
});

A different solution might be to extend the view and override the setPressed(Boolean) method. The method is internally called when the change of the pressed state happens. Then change the size of the text accordingly in the method call (don't forget to call the super).

curl posting with header application/x-www-form-urlencoded

 $curl = curl_init();
 curl_setopt_array($curl, array(
            CURLOPT_URL => "http://example.com",
            CURLOPT_RETURNTRANSFER => true,
            CURLOPT_ENCODING => "",
            CURLOPT_MAXREDIRS => 10,
            CURLOPT_TIMEOUT => 30,
            CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
            CURLOPT_CUSTOMREQUEST => "POST",
            CURLOPT_POSTFIELDS => "value1=111&value2=222",
            CURLOPT_HTTPHEADER => array(
                "cache-control: no-cache",
                "content-type: application/x-www-form-urlencoded"
            ),
        ));
 $response = curl_exec($curl);
 $err = curl_error($curl);

 curl_close($curl);

 if (!$err)
 {
      var_dump($response);
 }

How to use EOF to run through a text file in C?

One possible C loop would be:

#include <stdio.h>
int main()
{
    int c;
    while ((c = getchar()) != EOF)
    {
        /*
        ** Do something with c, such as check against '\n'
        ** and increment a line counter.
        */
    }
}

For now, I would ignore feof and similar functions. Exprience shows that it is far too easy to call it at the wrong time and process something twice in the belief that eof hasn't yet been reached.

Pitfall to avoid: using char for the type of c. getchar returns the next character cast to an unsigned char and then to an int. This means that on most [sane] platforms the value of EOF and valid "char" values in c don't overlap so you won't ever accidentally detect EOF for a 'normal' char.

JavaScript calculate the day of the year (1 - 366)

Following OP's edit:

_x000D_
_x000D_
var now = new Date();_x000D_
var start = new Date(now.getFullYear(), 0, 0);_x000D_
var diff = now - start;_x000D_
var oneDay = 1000 * 60 * 60 * 24;_x000D_
var day = Math.floor(diff / oneDay);_x000D_
console.log('Day of year: ' + day);
_x000D_
_x000D_
_x000D_

Edit: The code above will fail when now is a date in between march 26th and October 29th andnow's time is before 1AM (eg 00:59:59). This is due to the code not taking daylight savings time into account. You should compensate for this:

_x000D_
_x000D_
var now = new Date();_x000D_
var start = new Date(now.getFullYear(), 0, 0);_x000D_
var diff = (now - start) + ((start.getTimezoneOffset() - now.getTimezoneOffset()) * 60 * 1000);_x000D_
var oneDay = 1000 * 60 * 60 * 24;_x000D_
var day = Math.floor(diff / oneDay);_x000D_
console.log('Day of year: ' + day);
_x000D_
_x000D_
_x000D_

Move an array element from one array position to another

It is stated in many places (adding custom functions into Array.prototype) playing with the Array prototype could be a bad idea, anyway I combined the best from various posts, I came with this, using modern Javascript:

    Object.defineProperty(Array.prototype, 'immutableMove', {
        enumerable: false,
        value: function (old_index, new_index) {
            var copy = Object.assign([], this)
            if (new_index >= copy.length) {
                var k = new_index - copy.length;
                while ((k--) + 1) { copy.push(undefined); }
            }
            copy.splice(new_index, 0, copy.splice(old_index, 1)[0]);
            return copy
        }
    });

    //how to use it
    myArray=[0, 1, 2, 3, 4];
    myArray=myArray.immutableMove(2, 4);
    console.log(myArray);
    //result: 0, 1, 3, 4, 2

Hope can be useful to anyone

Search and replace in bash using regular expressions

This actually can be done in pure bash:

hello=ho02123ware38384you443d34o3434ingtod38384day
re='(.*)[0-9]+(.*)'
while [[ $hello =~ $re ]]; do
  hello=${BASH_REMATCH[1]}${BASH_REMATCH[2]}
done
echo "$hello"

...yields...

howareyoudoingtodday

Why is visible="false" not working for a plain html table?

For the best practice - use style="display:"

it will work every where..

How can I round down a number in Javascript?

Round towards negative infinity - Math.floor()

+3.5 => +3.0
-3.5 => -4.0

Round towards zero can be done using Math.trunc(). Older browsers do not support this function. If you need to support these, you can use Math.ceil() for negative numbers and Math.floor() for positive numbers.

+3.5 => +3.0 using Math.floor()
-3.5 => -3.0 using Math.ceil()

Does Python have an ordered set?

I can do you one better than an OrderedSet: boltons has a pure-Python, 2/3-compatible IndexedSet type that is not only an ordered set, but also supports indexing (as with lists).

Simply pip install boltons (or copy setutils.py into your codebase), import the IndexedSet and:

>>> from boltons.setutils import IndexedSet
>>> x = IndexedSet(list(range(4)) + list(range(8)))
>>> x
IndexedSet([0, 1, 2, 3, 4, 5, 6, 7])
>>> x - set(range(2))
IndexedSet([2, 3, 4, 5, 6, 7])
>>> x[-1]
7
>>> fcr = IndexedSet('freecreditreport.com')
>>> ''.join(fcr[:fcr.index('.')])
'frecditpo'

Everything is unique and retained in order. Full disclosure: I wrote the IndexedSet, but that also means you can bug me if there are any issues. :)

How do I get the APK of an installed app without root access?

List PackageManager.getInstalledApplications() will give you a list of the installed applications, and ApplicationInfo.sourceDir is the path to the .apk file.

// in oncreate
   PackageManager pm = getPackageManager(); 
   for (ApplicationInfo app : pm.getInstalledApplications(0)) {
 Log.d("PackageList", "package: " + app.packageName + ", sourceDir: " + app.sourceDir);
 }

//output is something like
D/PackageList(5010): package: com.example.xmlparse, sourceDir: /data/app   /com.example.xmlparse-2.apk
D/PackageList(5010): package: com.examples.android.calendar, sourceDir: /data/app/com.examples.android.calendar-2.apk
D/PackageList(5010): package: com.facebook.katana, sourceDir: /data/app/com.facebook.katana-1.apk
D/PackageList(5010): package: com.facebook.samples.profilepicture, sourceDir: /data/app/com.facebook.samples.profilepicture-1.apk
D/PackageList(5010): package: com.facebook.samples.sessionlogin, sourceDir: /data/app/com.facebook.samples.sessionlogin-1.apk
D/PackageList(5010): package: com.fitworld, sourceDir: /data/app/com.fitworld-2.apk
D/PackageList(5010): package: com.flipkart.android, sourceDir: /data/app/com.flipkart.android-1.apk
D/PackageList(5010): package: com.fmm.dm, sourceDir: /system/app/FmmDM.apk
D/PackageList(5010): package: com.fmm.ds, sourceDir: /system/app/FmmDS.apk

Difference between static memory allocation and dynamic memory allocation

There are three types of allocation — static, automatic, and dynamic.

Static Allocation means, that the memory for your variables is allocated when the program starts. The size is fixed when the program is created. It applies to global variables, file scope variables, and variables qualified with static defined inside functions.

Automatic memory allocation occurs for (non-static) variables defined inside functions, and is usually stored on the stack (though the C standard doesn't mandate that a stack is used). You do not have to reserve extra memory using them, but on the other hand, have also limited control over the lifetime of this memory. E.g: automatic variables in a function are only there until the function finishes.

void func() {
    int i; /* `i` only exists during `func` */
}

Dynamic memory allocation is a bit different. You now control the exact size and the lifetime of these memory locations. If you don't free it, you'll run into memory leaks, which may cause your application to crash, since at some point of time, system cannot allocate more memory.

int* func() {
    int* mem = malloc(1024);
    return mem;
}

int* mem = func(); /* still accessible */

In the upper example, the allocated memory is still valid and accessible, even though the function terminated. When you are done with the memory, you have to free it:

free(mem);

Remove empty strings from a list of strings

As reported by Aziz Alto filter(None, lstr) does not remove empty strings with a space ' ' but if you are sure lstr contains only string you can use filter(str.strip, lstr)

>>> lstr = ['hello', '', ' ', 'world', ' ']
>>> lstr
['hello', '', ' ', 'world', ' ']
>>> ' '.join(lstr).split()
['hello', 'world']
>>> filter(str.strip, lstr)
['hello', 'world']

Compare time on my pc

>>> from timeit import timeit
>>> timeit('" ".join(lstr).split()', "lstr=['hello', '', ' ', 'world', ' ']", number=10000000)
3.356455087661743
>>> timeit('filter(str.strip, lstr)', "lstr=['hello', '', ' ', 'world', ' ']", number=10000000)
5.276503801345825

The fastest solution to remove '' and empty strings with a space ' ' remains ' '.join(lstr).split().

As reported in a comment the situation is different if your strings contain spaces.

>>> lstr = ['hello', '', ' ', 'world', '    ', 'see you']
>>> lstr
['hello', '', ' ', 'world', '    ', 'see you']
>>> ' '.join(lstr).split()
['hello', 'world', 'see', 'you']
>>> filter(str.strip, lstr)
['hello', 'world', 'see you']

You can see that filter(str.strip, lstr) preserve strings with spaces on it but ' '.join(lstr).split() will split this strings.

"End of script output before headers" error in Apache

Since no answer is accepted, I would like to provide one possible solution. If your script is written on Windows and uploaded to a Linux server(through FTP), then the problem will raise usually. The reason is that Windows uses CRLF to end each line while Linux uses LF. So you should convert it from CRLF to LF with the help of an editor, such Atom, as following enter image description here

Can't connect to local MySQL server through socket '/tmp/mysql.sock

For me, the mysql server was not running. So, i started the mysql server through

mysql.server start

then

mysql_secure_installation

to secure the server and now I can visit the MySQL server through

mysql -u root -p

or

sudo mysql -u root -p

depending on your installation.

How to change the background color of the options menu?

protected void setMenuBackground() {
    getLayoutInflater().setFactory(new Factory() {
        @Override
        public View onCreateView (String name, Context context, AttributeSet attrs) {
            if (name.equalsIgnoreCase("com.android.internal.view.menu.IconMenuItemView")) {
                try {
                    // Ask our inflater to create the view
                    LayoutInflater f = getLayoutInflater();
                    final View view = f.createView(name, null, attrs);
                    // Kind of apply our own background
                    new Handler().post( new Runnable() {
                        public void run () {
                            view.setBackgroundResource(R.drawable.gray_gradient_background);
                        }
                    });
                    return view;
                }
                catch (InflateException e) {
                }
                catch (ClassNotFoundException e) {
                }
            }
            return null;
        }
    });
}

this is XML file

gradient 
    android:startColor="#AFAFAF" 
    android:endColor="#000000"
    android:angle="270"
shape

CSS Border Not Working

The height is a 100% unsure, try putting display: block; or display: inline-block;

Username and password in command for git push

It is possible but, before git 2.9.3 (august 2016), a git push would print the full url used when pushing back to the cloned repo.
That would include your username and password!

But no more: See commit 68f3c07 (20 Jul 2016), and commit 882d49c (14 Jul 2016) by Jeff King (peff).
(Merged by Junio C Hamano -- gitster -- in commit 71076e1, 08 Aug 2016)

push: anonymize URL in status output

Commit 47abd85 (fetch: Strip usernames from url's before storing them, 2009-04-17, Git 1.6.4) taught fetch to anonymize URLs.
The primary purpose there was to avoid sticking passwords in merge-commit messages, but as a side effect, we also avoid printing them to stderr.

The push side does not have the merge-commit problem, but it probably should avoid printing them to stderr. We can reuse the same anonymizing function.

Note that for this to come up, the credentials would have to appear either on the command line or in a git config file, neither of which is particularly secure.
So people should be switching to using credential helpers instead, which makes this problem go away.

But that's no excuse not to improve the situation for people who for whatever reason end up using credentials embedded in the URL.

MySQL with Node.js

Check out the node.js module list

  • node-mysql — A node.js module implementing the MySQL protocol
  • node-mysql2 — Yet another pure JS async driver. Pipelining, prepared statements.
  • node-mysql-libmysqlclient — MySQL asynchronous bindings based on libmysqlclient

node-mysql looks simple enough:

var mysql      = require('mysql');
var connection = mysql.createConnection({
  host     : 'example.org',
  user     : 'bob',
  password : 'secret',
});

connection.connect(function(err) {
  // connected! (unless `err` is set)
});

Queries:

var post  = {id: 1, title: 'Hello MySQL'};
var query = connection.query('INSERT INTO posts SET ?', post, function(err, result) {
  // Neat!
});
console.log(query.sql); // INSERT INTO posts SET `id` = 1, `title` = 'Hello MySQL'

Query to search all packages for table and/or column

Sometimes the column you are looking for may be part of the name of many other things that you are not interested in.

For example I was recently looking for a column called "BQR", which also forms part of many other columns such as "BQR_OWNER", "PROP_BQR", etc.

So I would like to have the checkbox that word processors have to indicate "Whole words only".

Unfortunately LIKE has no such functionality, but REGEXP_LIKE can help.

SELECT *
  FROM user_source
 WHERE regexp_like(text, '(\s|\.|,|^)bqr(\s|,|$)');

This is the regular expression to find this column and exclude the other columns with "BQR" as part of the name:

(\s|\.|,|^)bqr(\s|,|$)

The regular expression matches white-space (\s), or (|) period (.), or (|) comma (,), or (|) start-of-line (^), followed by "bqr", followed by white-space, comma or end-of-line ($).

Replace non-ASCII characters with a single space

If the replacement character can be '?' instead of a space, then I'd suggest result = text.encode('ascii', 'replace').decode():

"""Test the performance of different non-ASCII replacement methods."""


import re
from timeit import timeit


# 10_000 is typical in the project that I'm working on and most of the text
# is going to be non-ASCII.
text = 'Æ' * 10_000


print(timeit(
    """
result = ''.join([c if ord(c) < 128 else '?' for c in text])
    """,
    number=1000,
    globals=globals(),
))

print(timeit(
    """
result = text.encode('ascii', 'replace').decode()
    """,
    number=1000,
    globals=globals(),
))

Results:

0.7208260721400134
0.009975979187503592

Getting the 'external' IP address in Java

As @Donal Fellows wrote, you have to query the network interface instead of the machine. This code from the javadocs worked for me:

The following example program lists all the network interfaces and their addresses on a machine:

import java.io.*;
import java.net.*;
import java.util.*;
import static java.lang.System.out;

public class ListNets {

    public static void main(String args[]) throws SocketException {
        Enumeration<NetworkInterface> nets = NetworkInterface.getNetworkInterfaces();
        for (NetworkInterface netint : Collections.list(nets))
            displayInterfaceInformation(netint);
    }

    static void displayInterfaceInformation(NetworkInterface netint) throws SocketException {
        out.printf("Display name: %s\n", netint.getDisplayName());
        out.printf("Name: %s\n", netint.getName());
        Enumeration<InetAddress> inetAddresses = netint.getInetAddresses();
        for (InetAddress inetAddress : Collections.list(inetAddresses)) {
            out.printf("InetAddress: %s\n", inetAddress);
        }
        out.printf("\n");
     }
} 

The following is sample output from the example program:

Display name: TCP Loopback interface
Name: lo
InetAddress: /127.0.0.1

Display name: Wireless Network Connection
Name: eth0
InetAddress: /192.0.2.0

From docs.oracle.com

scp from remote host to local host

There must be a user in the AllowUsers section, in the config file /etc/ssh/ssh_config, in the remote machine. You might have to restart sshd after editing the config file.

And then you can copy for example the file "test.txt" from a remote host to the local host

scp [email protected]:test.txt /local/dir


@cool_cs you can user ~ symbol ~/Users/djorge/Desktop if it's your home dir.

In UNIX, absolute paths must start with '/'.

How to grant "grant create session" privilege?

You can grant system privileges with or without the admin option. The default being without admin option.

GRANT CREATE SESSION TO username

or with admin option:

GRANT CREATE SESSION TO username WITH ADMIN OPTION

The Grantee with the ADMIN OPTION can grant and revoke privileges to other users

Fundamental difference between Hashing and Encryption algorithms

Well, you could look it up in Wikipedia... But since you want an explanation, I'll do my best here:

Hash Functions

They provide a mapping between an arbitrary length input, and a (usually) fixed length (or smaller length) output. It can be anything from a simple crc32, to a full blown cryptographic hash function such as MD5 or SHA1/2/256/512. The point is that there's a one-way mapping going on. It's always a many:1 mapping (meaning there will always be collisions) since every function produces a smaller output than it's capable of inputting (If you feed every possible 1mb file into MD5, you'll get a ton of collisions).

The reason they are hard (or impossible in practicality) to reverse is because of how they work internally. Most cryptographic hash functions iterate over the input set many times to produce the output. So if we look at each fixed length chunk of input (which is algorithm dependent), the hash function will call that the current state. It will then iterate over the state and change it to a new one and use that as feedback into itself (MD5 does this 64 times for each 512bit chunk of data). It then somehow combines the resultant states from all these iterations back together to form the resultant hash.

Now, if you wanted to decode the hash, you'd first need to figure out how to split the given hash into its iterated states (1 possibility for inputs smaller than the size of a chunk of data, many for larger inputs). Then you'd need to reverse the iteration for each state. Now, to explain why this is VERY hard, imagine trying to deduce a and b from the following formula: 10 = a + b. There are 10 positive combinations of a and b that can work. Now loop over that a bunch of times: tmp = a + b; a = b; b = tmp. For 64 iterations, you'd have over 10^64 possibilities to try. And that's just a simple addition where some state is preserved from iteration to iteration. Real hash functions do a lot more than 1 operation (MD5 does about 15 operations on 4 state variables). And since the next iteration depends on the state of the previous and the previous is destroyed in creating the current state, it's all but impossible to determine the input state that led to a given output state (for each iteration no less). Combine that, with the large number of possibilities involved, and decoding even an MD5 will take a near infinite (but not infinite) amount of resources. So many resources that it's actually significantly cheaper to brute-force the hash if you have an idea of the size of the input (for smaller inputs) than it is to even try to decode the hash.

Encryption Functions

They provide a 1:1 mapping between an arbitrary length input and output. And they are always reversible. The important thing to note is that it's reversible using some method. And it's always 1:1 for a given key. Now, there are multiple input:key pairs that might generate the same output (in fact there usually are, depending on the encryption function). Good encrypted data is indistinguishable from random noise. This is different from a good hash output which is always of a consistent format.

Use Cases

Use a hash function when you want to compare a value but can't store the plain representation (for any number of reasons). Passwords should fit this use-case very well since you don't want to store them plain-text for security reasons (and shouldn't). But what if you wanted to check a filesystem for pirated music files? It would be impractical to store 3 mb per music file. So instead, take the hash of the file, and store that (md5 would store 16 bytes instead of 3mb). That way, you just hash each file and compare to the stored database of hashes (This doesn't work as well in practice because of re-encoding, changing file headers, etc, but it's an example use-case).

Use a hash function when you're checking validity of input data. That's what they are designed for. If you have 2 pieces of input, and want to check to see if they are the same, run both through a hash function. The probability of a collision is astronomically low for small input sizes (assuming a good hash function). That's why it's recommended for passwords. For passwords up to 32 characters, md5 has 4 times the output space. SHA1 has 6 times the output space (approximately). SHA512 has about 16 times the output space. You don't really care what the password was, you care if it's the same as the one that was stored. That's why you should use hashes for passwords.

Use encryption whenever you need to get the input data back out. Notice the word need. If you're storing credit card numbers, you need to get them back out at some point, but don't want to store them plain text. So instead, store the encrypted version and keep the key as safe as possible.

Hash functions are also great for signing data. For example, if you're using HMAC, you sign a piece of data by taking a hash of the data concatenated with a known but not transmitted value (a secret value). So, you send the plain-text and the HMAC hash. Then, the receiver simply hashes the submitted data with the known value and checks to see if it matches the transmitted HMAC. If it's the same, you know it wasn't tampered with by a party without the secret value. This is commonly used in secure cookie systems by HTTP frameworks, as well as in message transmission of data over HTTP where you want some assurance of integrity in the data.

A note on hashes for passwords:

A key feature of cryptographic hash functions is that they should be very fast to create, and very difficult/slow to reverse (so much so that it's practically impossible). This poses a problem with passwords. If you store sha512(password), you're not doing a thing to guard against rainbow tables or brute force attacks. Remember, the hash function was designed for speed. So it's trivial for an attacker to just run a dictionary through the hash function and test each result.

Adding a salt helps matters since it adds a bit of unknown data to the hash. So instead of finding anything that matches md5(foo), they need to find something that when added to the known salt produces md5(foo.salt) (which is very much harder to do). But it still doesn't solve the speed problem since if they know the salt it's just a matter of running the dictionary through.

So, there are ways of dealing with this. One popular method is called key strengthening (or key stretching). Basically, you iterate over a hash many times (thousands usually). This does two things. First, it slows down the runtime of the hashing algorithm significantly. Second, if implemented right (passing the input and salt back in on each iteration) actually increases the entropy (available space) for the output, reducing the chances of collisions. A trivial implementation is:

var hash = password + salt;
for (var i = 0; i < 5000; i++) {
    hash = sha512(hash + password + salt);
}

There are other, more standard implementations such as PBKDF2, BCrypt. But this technique is used by quite a few security related systems (such as PGP, WPA, Apache and OpenSSL).

The bottom line, hash(password) is not good enough. hash(password + salt) is better, but still not good enough... Use a stretched hash mechanism to produce your password hashes...

Another note on trivial stretching

Do not under any circumstances feed the output of one hash directly back into the hash function:

hash = sha512(password + salt); 
for (i = 0; i < 1000; i++) {
    hash = sha512(hash); // <-- Do NOT do this!
}

The reason for this has to do with collisions. Remember that all hash functions have collisions because the possible output space (the number of possible outputs) is smaller than then input space. To see why, let's look at what happens. To preface this, let's make the assumption that there's a 0.001% chance of collision from sha1() (it's much lower in reality, but for demonstration purposes).

hash1 = sha1(password + salt);

Now, hash1 has a probability of collision of 0.001%. But when we do the next hash2 = sha1(hash1);, all collisions of hash1 automatically become collisions of hash2. So now, we have hash1's rate at 0.001%, and the 2nd sha1() call adds to that. So now, hash2 has a probability of collision of 0.002%. That's twice as many chances! Each iteration will add another 0.001% chance of collision to the result. So, with 1000 iterations, the chance of collision jumped from a trivial 0.001% to 1%. Now, the degradation is linear, and the real probabilities are far smaller, but the effect is the same (an estimation of the chance of a single collision with md5 is about 1/(2128) or 1/(3x1038). While that seems small, thanks to the birthday attack it's not really as small as it seems).

Instead, by re-appending the salt and password each time, you're re-introducing data back into the hash function. So any collisions of any particular round are no longer collisions of the next round. So:

hash = sha512(password + salt);
for (i = 0; i < 1000; i++) {
    hash = sha512(hash + password + salt);
}

Has the same chance of collision as the native sha512 function. Which is what you want. Use that instead.

Save PL/pgSQL output from PostgreSQL to a CSV file

In pgAdmin III there is an option to export to file from the query window. In the main menu it's Query -> Execute to file or there's a button that does the same thing (it's a green triangle with a blue floppy disk as opposed to the plain green triangle which just runs the query). If you're not running the query from the query window then I'd do what IMSoP suggested and use the copy command.

How do you round UP a number in Python?

If working with integers, one way of rounding up is to take advantage of the fact that // rounds down: Just do the division on the negative number, then negate the answer. No import, floating point, or conditional needed.

rounded_up = -(-numerator // denominator)

For example:

>>> print(-(-101 // 5))
21

javascript jquery radio button click

this should be good

$(document).ready(function() {
    $('input:radio').change(function() {
       alert('ole');
    });
});

Which font is used in Visual Studio Code Editor and how to change fonts?

In the default settings, VS Code uses the following fonts (14 pt) in descending order:

  • Monaco
  • Menlo
  • Consolas
  • "Droid Sans Mono"
  • "Inconsolata"
  • "Courier New"
  • monospace (fallback)

How to verify: VS Code runs in a browser. In the first version, you could hit F12 to open the Developer Tools. Inspecting the DOM, you can find a containing several s that make up that line of code. Inspecting one of those spans, you can see that font-family is just the list above.

relevant areas

Protecting cells in Excel but allow these to be modified by VBA script

A basic but simple to understand answer:

Sub Example()
    ActiveSheet.Unprotect
    Program logic...
    ActiveSheet.Protect
End Sub

Notepad++ add to every line

In order to do it in one go:

  1. Copy and paste the following example text in your notepad++ window:

http:\blahblah.com

http:\blahnotblah.com

http:\blahandgainblah.com

  1. Press Ctrl+H on the notepad++ window
  2. In the Find what box type: ^(.+)$. Here ^ represents the start of the line. $ represents the end of the line. (.+) means any character in between the start and the end of the line and it would be group 1.
  3. In the Replace with box type: WhateverFrontText(\1)WhatEverEndText. Here (\1) means whatever text in a line.
  4. Check the check box Wrap around
  5. Search mode: Regular expression
  6. Result:

WhateverFrontTexthttp:\blahblah.comWhatEverEndText

WhateverFrontTexthttp:\blahnotblah.comWhatEverEndText

WhateverFrontTexthttp:\blahandgainblah.comWhatEverEndText

  1. Screenshot of the notepad++ options and result: enter image description here

How to create named and latest tag in Docker?

You can have multiple tags when building the image:

$ docker build -t whenry/fedora-jboss:latest -t whenry/fedora-jboss:v2.1 .

Reference: https://docs.docker.com/engine/reference/commandline/build/#tag-image-t

How to read a PEM RSA private key from .NET

Check http://msdn.microsoft.com/en-us/library/dd203099.aspx

under Cryptography Application Block.

Don't know if you will get your answer, but it's worth a try.

Edit after Comment.

Ok then check this code.

using System.Security.Cryptography;


public static string DecryptEncryptedData(stringBase64EncryptedData, stringPathToPrivateKeyFile) { 
    X509Certificate2 myCertificate; 
    try{ 
        myCertificate = new X509Certificate2(PathToPrivateKeyFile); 
    } catch{ 
        throw new CryptographicException("Unable to open key file."); 
    } 

    RSACryptoServiceProvider rsaObj; 
    if(myCertificate.HasPrivateKey) { 
         rsaObj = (RSACryptoServiceProvider)myCertificate.PrivateKey; 
    } else 
        throw new CryptographicException("Private key not contained within certificate."); 

    if(rsaObj == null) 
        return String.Empty; 

    byte[] decryptedBytes; 
    try{ 
        decryptedBytes = rsaObj.Decrypt(Convert.FromBase64String(Base64EncryptedData), false); 
    } catch { 
        throw new CryptographicException("Unable to decrypt data."); 
    } 

    //    Check to make sure we decrpyted the string 
   if(decryptedBytes.Length == 0) 
        return String.Empty; 
    else 
        return System.Text.Encoding.UTF8.GetString(decryptedBytes); 
} 

How to check for empty value in Javascript?

First, I would check what i gets initialized to, to see if the elements returned by getElementsByName are what you think they are. Maybe split the problem by trying it with a hard-coded name like timetemp0, without the concatenation. You can also run the code through a browser debugger (FireBug, Chrome Dev Tools, IE Dev Tools).

Also, for your if-condition, this should suffice:

if (!timetemp[0].value) {
    // The value is empty.
}
else {
    // The value is not empty.
}

The empty string in Javascript is a falsey value, so the logical negation of that will get you into the if-block.

How to Detect Browser Window /Tab Close Event?

Solution Posted Here

After my initial research i found that when we close a browser, the browser will close all the tabs one by one to completely close the browser. Hence, i observed that there will be very little time delay between closing the tabs. So I taken this time delay as my main validation point and able to achieve the browser and tab close event detection.

//Detect Browser or Tab Close Events
$(window).on('beforeunload',function(e) {
  e = e || window.event;
  var localStorageTime = localStorage.getItem('storagetime')
  if(localStorageTime!=null && localStorageTime!=undefined){
    var currentTime = new Date().getTime(),
        timeDifference = currentTime - localStorageTime;

    if(timeDifference<25){//Browser Closed
       localStorage.removeItem('storagetime');
    }else{//Browser Tab Closed
       localStorage.setItem('storagetime',new Date().getTime());
    }

  }else{
    localStorage.setItem('storagetime',new Date().getTime());
  }
});

JSFiddle Link

How to install Python packages from the tar.gz file without using pip install

You may use pip for that without using the network. See in the docs (search for "Install a particular source archive file"). Any of those should work:

pip install relative_path_to_seaborn.tar.gz    
pip install absolute_path_to_seaborn.tar.gz    
pip install file:///absolute_path_to_seaborn.tar.gz    

Or you may uncompress the archive and use setup.py directly with either pip or python:

cd directory_containing_tar.gz
tar -xvzf seaborn-0.10.1.tar.gz
pip install seaborn-0.10.1
python setup.py install

Of course, you should also download required packages and install them the same way before you proceed.

WebForms UnobtrusiveValidationMode requires a ScriptResourceMapping for 'jquery'. Please add a ScriptResourceMapping named jquery(case-sensitive)

Unobtrusive validation is enabled by default in new version of ASP.NET. Unobtrusive validation aims to decrease the page size by replacing the inline JavaScript for performing validation with a small JavaScript library that uses jQuery.

You can either disable it by editing web.config to include the following:

<appSettings>
  <add key="ValidationSettings:UnobtrusiveValidationMode" value="None" />
</appSettings>

Or better yet properly configure it by modifying the Application_Start method in global.asax:

void Application_Start(object sender, EventArgs e) 
{
    RouteConfig.RegisterRoutes(System.Web.Routing.RouteTable.Routes);
    ScriptManager.ScriptResourceMapping.AddDefinition("jquery",
        new ScriptResourceDefinition
        {
            Path = "/~Scripts/jquery-2.1.1.min.js"
        }
    );
}

Page 399 of Beginning ASP.NET 4.5.1 in C# and VB provides a discussion on the benefit of unobtrusive validation and a walkthrough for configuring it.

For those looking for RouteConfig. It is added automatically when you make a new project in visual studio to the App_Code folder. The contents look something like this:

using System;
using System.Collections.Generic;
using System.Web;
using System.Web.Routing;
using Microsoft.AspNet.FriendlyUrls;

namespace @default
{
    public static class RouteConfig
    {
        public static void RegisterRoutes(RouteCollection routes)
        {
            var settings = new FriendlyUrlSettings();
            settings.AutoRedirectMode = RedirectMode.Permanent;
            routes.EnableFriendlyUrls(settings);
        }
    }
}

How to set recurring schedule for xlsm file using Windows Task Scheduler

I referred a blog by Kim for doing this and its working fine for me. See the blog

The automated execution of macro can be accomplished with the help of a VB Script file which is being invoked by Windows Task Scheduler at specified times.

Remember to replace 'YourWorkbook' with the name of the workbook you want to open and replace 'YourMacro' with the name of the macro you want to run.

See the VB Script File (just named it RunExcel.VBS):

    ' Create a WshShell to get the current directory
Dim WshShell
Set WshShell = CreateObject("WScript.Shell")

' Create an Excel instance
Dim myExcelWorker
Set myExcelWorker = CreateObject("Excel.Application") 

' Disable Excel UI elements
myExcelWorker.DisplayAlerts = False
myExcelWorker.AskToUpdateLinks = False
myExcelWorker.AlertBeforeOverwriting = False
myExcelWorker.FeatureInstall = msoFeatureInstallNone

' Tell Excel what the current working directory is 
' (otherwise it can't find the files)
Dim strSaveDefaultPath
Dim strPath
strSaveDefaultPath = myExcelWorker.DefaultFilePath
strPath = WshShell.CurrentDirectory
myExcelWorker.DefaultFilePath = strPath

' Open the Workbook specified on the command-line 
Dim oWorkBook
Dim strWorkerWB
strWorkerWB = strPath & "\YourWorkbook.xls"

Set oWorkBook = myExcelWorker.Workbooks.Open(strWorkerWB)

' Build the macro name with the full path to the workbook
Dim strMacroName
strMacroName = "'" & strPath & "\YourWorkbook" & "!Sheet1.YourMacro"
on error resume next 
   ' Run the calculation macro
   myExcelWorker.Run strMacroName
   if err.number <> 0 Then
      ' Error occurred - just close it down.
   End If
   err.clear
on error goto 0 

oWorkBook.Save 

myExcelWorker.DefaultFilePath = strSaveDefaultPath

' Clean up and shut down
Set oWorkBook = Nothing

' Don’t Quit() Excel if there are other Excel instances 
' running, Quit() will shut those down also
if myExcelWorker.Workbooks.Count = 0 Then
   myExcelWorker.Quit
End If

Set myExcelWorker = Nothing
Set WshShell = Nothing

You can test this VB Script from command prompt:

>> cscript.exe RunExcel.VBS

Once you have the VB Script file and workbook tested so that it does what you want, you can then use Microsoft Task Scheduler (Control Panel-> Administrative Tools--> Task Scheduler) to execute ‘cscript.exe RunExcel.vbs’ automatically for you.

Please note the path of the macro should be in correct format and inside single quotes like:

strMacroName = "'" & strPath & "\YourWorkBook.xlsm'" & 
"!ModuleName.MacroName"

How to start rails server?

On rails 3, the simpliest way is rails s. In rails 2, you can use ./script/server start.

You can also use another servers, like thin or unicorn, that also provide more performance.

I use unicorn, you can easily start it with unicorn_rails.

BTW, if you use another things, like a worker (sidekiq, resque, etc), I strongly recommend you to use foreman, so you can start all your jobs in one terminal windows with one command and get a unified log.

Make a Bash alias that takes a parameter?

You don't have to do anything, alias does this automatically.

For example, if i want to make git pull origin master parameterized, i can simply create an alias as follows:

alias gpull = 'git pull origin '

and when actually calling it, you can pass 'master' (the branch name) as a parameter, like this:

gpull master
//or any other branch
gpull mybranch

Read and write a String from text file

Swift 3.x - 5.x

The Best Example is to Create a Local Logfile with an Extension .txt that can visible and show in the "Files App" with current date and Time as a File Name

just add this code in info.plist enable these two features

  UIFileSharingEnabled
  LSSupportsOpeningDocumentsInPlace

and this Function Below

var logfileName : String = ""
func getTodayString() -> String{

    let date = Date()
    let calender = Calendar.current
    let components = calender.dateComponents([.year,.month,.day,.hour,.minute,.second], from: date)

    let year = components.year
    let month = components.month
    let day = components.day
    let hour = components.hour
    let minute = components.minute
    let second = components.second

    let today_string = String(year!) + "-" + String(month!) + "-" + String(day!) + "-" + String(hour!)  + "" + String(minute!) + "" +  String(second!)+".txt"

    return today_string

}

func LogCreator(){
    logfileName = getTodayString()

    print("LogCreator: Logfile Generated Named: \(logfileName)")

    let file = logfileName //this is the file. we will write to and read from it

    let text = "some text" //just a text

    if let dir = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first {

        let fileURL = dir.appendingPathComponent(file)
        let documentPath = NSSearchPathForDirectoriesInDomains(.documentDirectory,.userDomainMask, true)[0]
        print("LogCreator: The Logs are Stored at location \(documentPath)")


        //writing
        do {
            try text.write(to: fileURL, atomically: false, encoding: .utf8)
        }
        catch {/* error handling here */}

        //reading
        do {
            let text2 = try String(contentsOf: fileURL, encoding: .utf8)
            print("LogCreator: The Detail log are :-\(text2)")
        }
        catch {/* error handling here */}
    }
}


  [1]: https://i.stack.imgur.com/4eg12.png

How do I check particular attributes exist or not in XML?

You can use LINQ to XML,

XDocument doc = XDocument.Load(file);

var result = (from ele in doc.Descendants("section")
              select ele).ToList();

foreach (var t in result)
{
    if (t.Attributes("split").Count() != 0)
    {
        // Exist
    }

    // Suggestion from @UrbanEsc
    if(t.Attributes("split").Any())
    {

    }
}

OR

 XDocument doc = XDocument.Load(file);

 var result = (from ele in doc.Descendants("section").Attributes("split")
               select ele).ToList();

 foreach (var t in result)
 {
     // Response.Write("<br/>" +  t.Value);
 }

Convert double/float to string

Use snprintf() from stdlib.h. Worked for me.

double num = 123412341234.123456789; 
char output[50];

snprintf(output, 50, "%f", num);

printf("%s", output);

How to search for a string in text files?

Here's another way to possibly answer your question using the find function which gives you a literal numerical value of where something truly is

open('file', 'r').read().find('')

in find write the word you want to find and 'file' stands for your file name

Ajax passing data to php script

Try sending the data like this:

var data = {};
data.album = this.title;

Then you can access it like

$_POST['album']

Notice not a 'GET'

Access host database from a docker container

From Docker 17.06 onwards, a special Mac-only DNS name is available in docker containers that resolves to the IP address of the host. It is:

docker.for.mac.localhost

The documentation is here: https://docs.docker.com/docker-for-mac/networking/#httphttps-proxy-support

Alternate table with new not null Column in existing table in SQL

Choose either:

a) Create not null with some valid default value
b) Create null, fill it, alter to not null

Correct way to write loops for promise.

Here's another method (ES6 w/std Promise). Uses lodash/underscore type exit criteria (return === false). Note that you could easily add an exitIf() method in options to run in doOne().

const whilePromise = (fnReturningPromise,options = {}) => { 
    // loop until fnReturningPromise() === false
    // options.delay - setTimeout ms (set to 0 for 1 tick to make non-blocking)
    return new Promise((resolve,reject) => {
        const doOne = () => {
            fnReturningPromise()
            .then((...args) => {
                if (args.length && args[0] === false) {
                    resolve(...args);
                } else {
                    iterate();
                }
            })
        };
        const iterate = () => {
            if (options.delay !== undefined) {
                setTimeout(doOne,options.delay);
            } else {
                doOne();
            }
        }
        Promise.resolve()
        .then(iterate)
        .catch(reject)
    })
};

About .bash_profile, .bashrc, and where should alias be written in?

Check out http://mywiki.wooledge.org/DotFiles for an excellent resource on the topic aside from man bash.

Summary:

  • You only log in once, and that's when ~/.bash_profile or ~/.profile is read and executed. Since everything you run from your login shell inherits the login shell's environment, you should put all your environment variables in there. Like LESS, PATH, MANPATH, LC_*, ... For an example, see: My .profile
  • Once you log in, you can run several more shells. Imagine logging in, running X, and in X starting a few terminals with bash shells. That means your login shell started X, which inherited your login shell's environment variables, which started your terminals, which started your non-login bash shells. Your environment variables were passed along in the whole chain, so your non-login shells don't need to load them anymore. Non-login shells only execute ~/.bashrc, not /.profile or ~/.bash_profile, for this exact reason, so in there define everything that only applies to bash. That's functions, aliases, bash-only variables like HISTSIZE (this is not an environment variable, don't export it!), shell options with set and shopt, etc. For an example, see: My .bashrc
  • Now, as part of UNIX peculiarity, a login-shell does NOT execute ~/.bashrc but only ~/.profile or ~/.bash_profile, so you should source that one manually from the latter. You'll see me do that in my ~/.profile too: source ~/.bashrc.

Get a list of distinct values in List

Distinct the Note class by Author

var DistinctItems = Note.GroupBy(x => x.Author).Select(y => y.First());

foreach(var item in DistinctItems)
{
    //Add to other List
}

Getting the computer name in Java

I'm not so thrilled about the InetAddress.getLocalHost().getHostName() solution that you can find so many places on the Internet and indeed also here. That method will get you the hostname as seen from a network perspective. I can see two problems with this:

  1. What if the host has multiple network interfaces ? The host may be known on the network by multiple names. The one returned by said method is indeterminate afaik.

  2. What if the host is not connected to any network and has no network interfaces ?

All OS'es that I know of have the concept of naming a node/host irrespective of network. Sad that Java cannot return this in an easy way. This would be the environment variable COMPUTERNAME on all versions of Windows and the environment variable HOSTNAME on Unix/Linux/MacOS (or alternatively the output from host command hostname if the HOSTNAME environment variable is not available as is the case in old shells like Bourne and Korn).

I would write a method that would retrieve (depending on OS) those OS vars and only as a last resort use the InetAddress.getLocalHost().getHostName() method. But that's just me.

UPDATE (Unices)

As others have pointed out the HOSTNAME environment variable is typically not available to a Java application on Unix/Linux as it is not exported by default. Hence not a reliable method unless you are in control of the clients. This really sucks. Why isn't there a standard property with this information?

Alas, as far as I can see the only reliable way on Unix/Linux would be to make a JNI call to gethostname() or to use Runtime.exec() to capture the output from the hostname command. I don't particularly like any of these ideas but if anyone has a better idea I'm all ears. (update: I recently came across gethostname4j which seems to be the answer to my prayers).

Long read

I've created a long explanation in another answer on another post. In particular you may want to read it because it attempts to establish some terminology, gives concrete examples of when the InetAddress.getLocalHost().getHostName() solution will fail, and points to the only safe solution that I know of currently, namely gethostname4j.

It's sad that Java doesn't provide a method for obtaining the computername. Vote for JDK-8169296 if you are able to.

Using await outside of an async function

you can do top level await since typescript 3.8
https://www.typescriptlang.org/docs/handbook/release-notes/typescript-3-8.html#-top-level-await
From the post:
This is because previously in JavaScript (along with most other languages with a similar feature), await was only allowed within the body of an async function. However, with top-level await, we can use await at the top level of a module.

const response = await fetch("...");
const greeting = await response.text();
console.log(greeting);

// Make sure we're a module
export {};

Note there’s a subtlety: top-level await only works at the top level of a module, and files are only considered modules when TypeScript finds an import or an export. In some basic cases, you might need to write out export {} as some boilerplate to make sure of this.

Top level await may not work in all environments where you might expect at this point. Currently, you can only use top level await when the target compiler option is es2017 or above, and module is esnext or system. Support within several environments and bundlers may be limited or may require enabling experimental support.

How to mount the android img file under linux?

I have found that Furius ISO mount works best for me. I am using a Debian based distro Knoppix. I use this to Open system.img files all the time.

Furius ISO mount: https://packages.debian.org/sid/otherosfs/furiusisomount

"When I want to mount userdata.img by mount -o loop userdata.img /mnt/userdata (the same as system.img), it tells me mount: you must specify the filesystem type so I try the mount -t ext2 -o loop userdata.img /mnt/userdata, it said mount: wrong fs type, bad option, bad superblock on...

So, how to get the file from the inside of userdata.img?" To load .img files you have to select loop and load the .img Select loop

Next you select mount Select mount

Furius ISO mount handles all the other options loading the .img file to your /home/dir.

Resize jqGrid when browser is resized?

this seems to be working nicely for me

$(window).bind('resize', function() {
    jQuery("#grid").setGridWidth($('#parentDiv').width()-30, true);
}).trigger('resize');

Why is a div with "display: table-cell;" not affected by margin?

If you have div next each other like this

<div id="1" style="float:left; margin-right:5px">

</div>
<div id="2" style="float:left">

</div>

This should work!

Sorting a set of values

From a comment:

I want to sort each set.

That's easy. For any set s (or anything else iterable), sorted(s) returns a list of the elements of s in sorted order:

>>> s = set(['0.000000000', '0.009518000', '10.277200999', '0.030810999', '0.018384000', '4.918560000'])
>>> sorted(s)
['0.000000000', '0.009518000', '0.018384000', '0.030810999', '10.277200999', '4.918560000']

Note that sorted is giving you a list, not a set. That's because the whole point of a set, both in mathematics and in almost every programming language,* is that it's not ordered: the sets {1, 2} and {2, 1} are the same set.


You probably don't really want to sort those elements as strings, but as numbers (so 4.918560000 will come before 10.277200999 rather than after).

The best solution is most likely to store the numbers as numbers rather than strings in the first place. But if not, you just need to use a key function:

>>> sorted(s, key=float)
['0.000000000', '0.009518000', '0.018384000', '0.030810999', '4.918560000', '10.277200999']

For more information, see the Sorting HOWTO in the official docs.


* See the comments for exceptions.

What's is the difference between train, validation and test set, in neural networks?

Cross-validation set is used for model selection, for example, select the polynomial model with the least amount of errors for a given parameter set. The test set is then used to report the generalization error on the selected model. From here: https://www.coursera.org/learn/machine-learning/lecture/QGKbr/model-selection-and-train-validation-test-sets

How can I set selected option selected in vue.js 2?

Handling the errors

You are binding properties to nothing. :required in

<select class="form-control" v-model="selected" :required @change="changeLocation">

and :selected in

<option :selected>Choose Province</option>

If you set the code like so, your errors should be gone:

<template>
  <select class="form-control" v-model="selected" :required @change="changeLocation">
    <option>Choose Province</option>
    <option v-for="option in options" v-bind:value="option.id" >{{ option.name }}</option>
 </select>
</template>

Getting the select tags to have a default value

  1. you would now need to have a data property called selected so that v-model works. So,

    {
      data () {
        return {
          selected: "Choose Province"
        }
      }
    }
    
  2. If that seems like too much work, you can also do it like:

    <template>
      <select class="form-control" :required="true" @change="changeLocation">
       <option :selected="true">Choose Province</option>
       <option v-for="option in options" v-bind:value="option.id" >{{ option.name }}</option>
      </select>
    </template>
    

When to use which method?

  1. You can use the v-model approach if your default value depends on some data property.

  2. You can go for the second method if your default selected value happens to be the first option.

  3. You can also handle it programmatically by doing so:

    <select class="form-control" :required="true">
      <option 
       v-for="option in options" 
       v-bind:value="option.id"
       :selected="option == '<the default value you want>'"
      >{{ option }}</option>
    </select>
    

How can I open a website in my web browser using Python?

Actually it depends on what kind of uses. If you want to use it in a test-framework I highly recommend selenium-python. It is a great tool for testing automation related to web-browsers.

from selenium import webdriver

driver = webdriver.Firefox()
driver.get("http://www.python.org")

How to print React component on click of a button?

I was looking for a simple package that would do this very same task and did not find anything so I created https://github.com/gregnb/react-to-print

You can use it like so:

 <ReactToPrint
   trigger={() => <a href="#">Print this out!</a>}
   content={() => this.componentRef}
 />
 <ComponentToPrint ref={el => (this.componentRef = el)} />

iOS change navigation bar title font and color

It's a bit more readable using literals:

self.navigationController.navigationBar.titleTextAttributes = @{
                                                              NSFontAttributeName:[UIFont fontWithName:@"mplus-1c-regular" size:21],
                                                              NSForegroundColorAttributeName: [UIColor whiteColor]
                                                              };

Can promises have multiple arguments to onFulfilled?

The fulfillment value of a promise parallels the return value of a function and the rejection reason of a promise parallels the thrown exception of a function. Functions cannot return multiple values so promises must not have more than 1 fulfillment value.

I can't delete a remote master branch on git

As explained in "Deleting your master branch" by Matthew Brett, you need to change your GitHub repo default branch.

You need to go to the GitHub page for your forked repository, and click on the “Settings” button.

Click on the "Branches" tab on the left hand side. There’s a “Default branch” dropdown list near the top of the screen.

From there, select placeholder (where placeholder is the dummy name for your new default branch).

Confirm that you want to change your default branch.

Now you can do (from the command line):

git push origin :master

Or, since 2012, you can delete that same branch directly on GitHub:

GitHub deletion

That was announced in Sept. 2013, a year after I initially wrote that answer.

For small changes like documentation fixes, typos, or if you’re just a walking software compiler, you can get a lot done in your browser without needing to clone the entire repository to your computer.


Note: for BitBucket, Tum reports in the comments:

About the same for Bitbucket

Repo -> Settings -> Repository details -> Main branch

SQL Server: Filter output of sp_who2

There's quite a few good sp_who3 user stored procedures out there - I'm sure Adam Machanic did a really good one, AFAIK.

Adam calls it Who Is Active: http://whoisactive.com

Easy way to concatenate two byte arrays

If you prefer ByteBuffer like @kalefranz, there is always the posibility to concatenate two byte[] (or even more) in one line, like this:

byte[] c = ByteBuffer.allocate(a.length+b.length).put(a).put(b).array();

jQuery equivalent of JavaScript's addEventListener method

_x000D_
_x000D_
$( "button" ).on( "click", function(event) {_x000D_
_x000D_
    alert( $( this ).html() );_x000D_
    console.log( event.target );_x000D_
_x000D_
} );
_x000D_
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.4.1/jquery.min.js"></script>_x000D_
_x000D_
<button>test 1</button>_x000D_
<button>test 2</button>
_x000D_
_x000D_
_x000D_

How to check permissions of a specific directory?

ls -lstr

This shows the normal ls view with permissions and user:group as well

Arrays in cookies PHP

You can also try to write different elements in different cookies. Cookies names can be set as array names and will be available to your PHP scripts as arrays but separate cookies are stored on the user's system. Consider explode() to set one cookie with multiple names and values. It is not recommended to use serialize() for this purpose, because it can result in security holes. Look at setcookie PHP function for more details

How to get a matplotlib Axes instance to plot to?

You can either

fig, ax = plt.subplots()  #create figure and axes
candlestick(ax, quotes, ...)

or

candlestick(plt.gca(), quotes) #get the axis when calling the function

The first gives you more flexibility. The second is much easier if candlestick is the only thing you want to plot

Disable password authentication for SSH

I followed these steps (for Mac).

In /etc/ssh/sshd_config change

#ChallengeResponseAuthentication yes
#PasswordAuthentication yes

to

ChallengeResponseAuthentication no
PasswordAuthentication no

Now generate the RSA key:

ssh-keygen -t rsa -P '' -f ~/.ssh/id_rsa

(For me an RSA key worked. A DSA key did not work.)

A private key will be generated in ~/.ssh/id_rsa along with ~/.ssh/id_rsa.pub (public key).

Now move to the .ssh folder: cd ~/.ssh

Enter rm -rf authorized_keys (sometimes multiple keys lead to an error).

Enter vi authorized_keys

Enter :wq to save this empty file

Enter cat ~/.ssh/id_rsa.pub >> ~/.ssh/authorized_keys

Restart the SSH:

sudo launchctl stop com.openssh.sshd
sudo launchctl start com.openssh.sshd

How to get a Docker container's IP address from the host

To extend ko-dos' answer, here's an alias to list all container names and their IP addresses:

alias docker-ips='docker ps | tail -n +2 | while read -a a; do name=${a[$((${#a[@]}-1))]}; echo -ne "$name\t"; docker inspect $name | grep IPAddress | cut -d \" -f 4; done'

Parse date string and change format

As this question comes often, here is the simple explanation.

datetime or time module has two important functions.

  • strftime - creates a string representation of date or time from a datetime or time object.
  • strptime - creates a datetime or time object from a string.

In both cases, we need a formating string. It is the representation that tells how the date or time is formatted in your string.

Now lets assume we have a date object.

>>> from datetime import datetime
>>> d = datetime(2010, 2, 15)
>>> d
datetime.datetime(2010, 2, 15, 0, 0)

If we want to create a string from this date in the format 'Mon Feb 15 2010'

>>> s = d.strftime('%a %b %d %y')
>>> print s
Mon Feb 15 10

Lets assume we want to convert this s again to a datetime object.

>>> new_date = datetime.strptime(s, '%a %b %d %y')
>>> print new_date
2010-02-15 00:00:00

Refer This document all formatting directives regarding datetime.

Read Variable from Web.Config

If you want the basics, you can access the keys via:

string myKey = System.Configuration.ConfigurationManager.AppSettings["myKey"].ToString();
string imageFolder = System.Configuration.ConfigurationManager.AppSettings["imageFolder"].ToString();

To access my web config keys I always make a static class in my application. It means I can access them wherever I require and I'm not using the strings all over my application (if it changes in the web config I'd have to go through all the occurrences changing them). Here's a sample:

using System.Configuration;

public static class AppSettingsGet
{    
    public static string myKey
    {
        get { return ConfigurationManager.AppSettings["myKey"].ToString(); }
    }

    public static string imageFolder
    {
        get { return ConfigurationManager.AppSettings["imageFolder"].ToString(); }
    }

    // I also get my connection string from here
    public static string ConnectionString
    {
       get { return ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString; }
    }
}

how to remove key+value from hash in javascript

Another option may be this John Resig remove method. can better fit what you need. if you know the index in the array.

How to solve the system.data.sqlclient.sqlexception (0x80131904) error

You also need to change the DataSource of the connection string. KELVIN-PC is the name of your local machine and the sql server is running on the default instance.

If you are sure the the server is running as the default instance, you can always use . in the DataSource, eg.

connectionString="Data Source=.;Initial Catalog=LMS;User ID=sa;Password=temperament"

otherwise, you need to specify the name of the instance of the server,

connectionString="Data Source=.\INSTANCENAME;Initial Catalog=LMS;User ID=sa;Password=temperament"

sendUserActionEvent() is null

I also encuntered the same in S4. I've tested the app in Galaxy Grand , HTC , Sony Experia but got only in s4. You can ignore it as its not related to your app.

How to correctly use Html.ActionLink with ASP.NET MVC 4 Areas

How I redirect to an area is add it as a parameter

@Html.Action("Action", "Controller", new { area = "AreaName" })

for the href portion of a link I use

@Url.Action("Action", "Controller", new { area = "AreaName" })

Run a shell script with an html button

This is really just an expansion of BBB's answer which lead to to get my experiment working.

This script will simply create a file /tmp/testfile when you click on the button that says "Open Script".

This requires 3 files.

  1. The actual HTML Website with a button.
  2. A php script which executes the script
  3. A Script

The File Tree:

root@test:/var/www/html# tree testscript/
testscript/
+-- index.html
+-- testexec.php
+-- test.sh

1. The main WebPage:

root@test:/var/www/html# cat testscript/index.html
<form action="/testscript/testexec.php">
    <input type="submit" value="Open Script">
</form>

2. The PHP Page that runs the script and redirects back to the main page:

root@test:/var/www/html# cat testscript/testexec.php
<?php
shell_exec("/var/www/html/testscript/test.sh");
header('Location: http://192.168.1.222/testscript/index.html?success=true');
?>

3. The Script :

root@test:/var/www/html# cat testscript/test.sh

#!/bin/bash

touch /tmp/testfile

How to find a min/max with Ruby

You can use

[5,10].min 

or

[4,7].max

It's a method for Arrays.

Bash loop ping successful

You probably shouldn't rely on textual output of a command to decide this, especially when the ping command gives you a perfectly good return value:

The ping utility returns an exit status of zero if at least one response was heard from the specified host; a status of two if the transmission was successful but no responses were received; or another value from <sysexits.h> if an error occurred.

In other words, use something like:

((count = 100))                            # Maximum number to try.
while [[ $count -ne 0 ]] ; do
    ping -c 1 8.8.8.8                      # Try once.
    rc=$?
    if [[ $rc -eq 0 ]] ; then
        ((count = 1))                      # If okay, flag to exit loop.
    fi
    ((count = count - 1))                  # So we don't go forever.
done

if [[ $rc -eq 0 ]] ; then                  # Make final determination.
    echo `say The internet is back up.`
else
    echo `say Timeout.`
fi

Empty an array in Java / processing

Take double array as an example, if the initial input values array is not empty, the following code snippet is superior to traditional direct for-loop in time complexity:

public static void resetValues(double[] values) {
  int len = values.length;
  if (len > 0) {
    values[0] = 0.0;
  }
  for (int i = 1; i < len; i += i) {
    System.arraycopy(values, 0, values, i, ((len - i) < i) ? (len - i) : i);
  }
}

Replace words in a string - Ruby

If you're dealing with natural language text and need to replace a word, not just part of a string, you have to add a pinch of regular expressions to your gsub as a plain text substitution can lead to disastrous results:

'mislocated cat, vindicating'.gsub('cat', 'dog')
=> "mislodoged dog, vindidoging"

Regular expressions have word boundaries, such as \b which matches start or end of a word. Thus,

'mislocated cat, vindicating'.gsub(/\bcat\b/, 'dog')
=> "mislocated dog, vindicating"

In Ruby, unlike some other languages like Javascript, word boundaries are UTF-8-compatible, so you can use it for languages with non-Latin or extended Latin alphabets:

'???? ? ??????, ??? ??????'.gsub(/\b????\b/, '?????')
=> "????? ? ??????, ??? ??????"

C# Create New T()

Take a look at new Constraint

public class MyClass<T> where T : new()
{
    protected T GetObject()
    {
        return new T();
    }
}

T could be a class that does not have a default constructor: in this case new T() would be an invalid statement. The new() constraint says that T must have a default constructor, which makes new T() legal.

You can apply the same constraint to a generic method:

public static T GetObject<T>() where T : new()
{
    return new T();
}

If you need to pass parameters:

protected T GetObject(params object[] args)
{
    return (T)Activator.CreateInstance(typeof(T), args);
}

How to print a float with 2 decimal places in Java?

You may use this quick codes below that changed itself at the end. Add how many zeros as refers to after the point

float y1 = 0.123456789;
DecimalFormat df = new DecimalFormat("#.00");  
y1 = Float.valueOf(df.format(y1));

The variable y1 was equals to 0.123456789 before. After the code it turns into 0.12 only.

How to list files in a directory in a C program?

Below code will only print files within directory and exclude directories within given directory while traversing.

#include <dirent.h>
#include <stdio.h>
#include <errno.h>
#include <sys/stat.h>
#include<string.h>
int main(void)
{
    DIR *d;
    struct dirent *dir;
    char path[1000]="/home/joy/Downloads";
    d = opendir(path);
    char full_path[1000];
    if (d)
    {
        while ((dir = readdir(d)) != NULL)
        {
            //Condition to check regular file.
            if(dir->d_type==DT_REG){
                full_path[0]='\0';
                strcat(full_path,path);
                strcat(full_path,"/");
                strcat(full_path,dir->d_name);
                printf("%s\n",full_path);
            }
        }
        closedir(d);
    }
    return(0);     
}

Call removeView() on the child's parent first

You can also do it by checking if View's indexOfView method if indexOfView method returns -1 then we can use.

ViewGroup's detachViewFromParent(v); followed by ViewGroup's removeDetachedView(v, true/false);

How can I see the raw SQL queries Django is running?

Another option, see logging options in settings.py described by this post

http://dabapps.com/blog/logging-sql-queries-django-13/

debug_toolbar slows down each page load on your dev server, logging does not so it's faster. Outputs can be dumped to console or file, so the UI is not as nice. But for views with lots of SQLs, it can take a long time to debug and optimize the SQLs through debug_toolbar since each page load is so slow.

How to append new data onto a new line

I presume that all you are wanting is simple string concatenation:

def storescores():

   hs = open("hst.txt","a")
   hs.write(name + " ")
   hs.close() 

Alternatively, change the " " to "\n" for a newline.

How to get DataGridView cell value in messagebox?

Sum all cells

        double X=0;
        if (datagrid.Rows.Count-1 > 0)
        {
           for(int i = 0; i < datagrid.Rows.Count-1; i++)
            {
               for(int j = 0; j < datagrid.Rows.Count-1; j++)
               {
                  X+=Convert.ToDouble(datagrid.Rows[i].Cells[j].Value.ToString());
               }
            } 
        }

how to fix stream_socket_enable_crypto(): SSL operation failed with code 1

To resolve this problem you first need to check the SSL certificates of the host your are connecting to. For example using ssllabs or other ssl tools. In my case the intermediate certificate was wrong.

If the certificate is ok, make sure the openSSL on your server is up to date. Run openssl -v to check your version. Maybe your version is to old to work with the certificate.

In very rare cases you might want to disable ssl security features like verify_peer, verify_peer_name or allow_self_signed. Please be very careful with this and never use this in production. This is only an option for temporary testing.

Background color of text in SVG

You can add style to your text:

  style="-webkit-tap-highlight-color: rgba(0, 0, 0, 0); 
    text-shadow: rgb(255, 255, 255) -2px -2px 0px, rgb(255, 255, 255) -2px 2px 0px, 
     rgb(255, 255, 255) 2px -2px 0px, rgb(255, 255, 255) 2px 2px 0px;"

White, in this example. Does not work in IE :)

How to express a One-To-Many relationship in Django

If the "many" model does not justify the creation of a model per-se (not the case here, but it might benefits other people), another alternative would be to rely on specific PostgreSQL data types, via the Django Contrib package

Postgres can deal with Array or JSON data types, and this may be a nice workaround to handle One-To-Many when the many-ies can only be tied to a single entity of the one.

Postgres allows you to access single elements of the array, which means that queries can be really fast, and avoid application-level overheads. And of course, Django implements a cool API to leverage this feature.

It obviously has the disadvantage of not being portable to others database backend, but I thougt it still worth mentionning.

Hope it may help some people looking for ideas.

Swift - how to make custom header for UITableView?

I have had some problems in Swift 5 with this. When using this function I had a wrong alignment with the header cell:

func tableView(_ tableView: UITableView, viewForHeaderInSection section: Int) -> UIView? {
     let headerCell = tableView.dequeueReusableCell(withIdentifier: "customTableCell") as! CustomTableCell
     return headerCell
}

The cell view was shown with a bad alignment and the top part of the tableview was shown. So I had to make some tweak like this:

func tableView(_ tableView: UITableView, viewForHeaderInSection section: Int) -> UIView? {
     let headerView = UIView.init(frame: CGRect(x: 0, y: 0, width: tableView.frame.size.width, height: 90))
     let headerCell = tableView.dequeueReusableCell(withIdentifier: "YOUR_CELL_IDENTIFIER")
     headerCell?.frame = headerView.bounds
     headerView.addSubview(headerCell!)
     return headerView
 }

I am having this problem in Swift 5 and Xcode 12.0.1, I don't know if it is just a problem for me or it is a bug. Hope it helps ! I have lost a morning...

smtp configuration for php mail

php's email() function hands the email over to a underlying mail transfer agent which is usually postfix on linux systems

so the preferred method on linux is to configure your postfix to use a relayhost, which is done by a line of

relayhost = smtp.example.com

in /etc/postfix/main.cf

however in the OP's scenario I somehow suspect that it's a job that his hosting team should have done

What is (x & 1) and (x >>= 1)?

(n & 1) will check if 'n' is odd or even, this is similar to (n%2).

  1. In case 'n' is odd (n & 1) will return true/1;

  2. Else it will return back false/0;


The '>>' in (n>>=1) is a bitwise operator called "Right shift", this operator will modify the value of 'n', the formula is:

(n >>= m) => (n = n>>m) => (n = n/2^m)

Go through GeeksforGeek's article on "Bitwise Operator's", recommended!

Is calculating an MD5 hash less CPU intensive than SHA family functions?

The real answer is : It depends

There are a couple factors to consider, the most obvious are : the cpu you are running these algorithms on and the implementation of the algorithms.

For instance, me and my friend both run the exact same openssl version and get slightly different results with different Intel Core i7 cpus.

My test at work with an Intel(R) Core(TM) i7-2600 CPU @ 3.40GHz

The 'numbers' are in 1000s of bytes per second processed.
type             16 bytes     64 bytes    256 bytes   1024 bytes   8192 bytes
md5              64257.97k   187370.26k   406435.07k   576544.43k   649827.67k
sha1             73225.75k   202701.20k   432679.68k   601140.57k   679900.50k

And his with an Intel(R) Core(TM) i7 CPU 920 @ 2.67GHz

The 'numbers' are in 1000s of bytes per second processed.
type             16 bytes     64 bytes    256 bytes   1024 bytes   8192 bytes
md5              51859.12k   156255.78k   350252.00k   513141.73k   590701.52k
sha1             56492.56k   156300.76k   328688.76k   452450.92k   508625.68k

We both are running the exact same binaries of OpenSSL 1.0.1j 15 Oct 2014 from the ArchLinux official package.

My opinion on this is that with the added security of sha1, cpu designers are more likely to improve the speed of sha1 and more programmers will be working on the algorithm's optimization than md5sum.

I guess that md5 will no longer be used some day since it seems that it has no advantage over sha1. I also tested some cases on real files and the results were always the same in both cases (likely limited by disk I/O).

md5sum of a large 4.6GB file took the exact same time than sha1sum of the same file, same goes with many small files (488 in the same directory). I ran the tests a dozen times and they were consitently getting the same results.

--

It would be very interesting to investigate this further. I guess there are some experts around that could provide a solid answer to why sha1 is getting faster than md5 on newer processors.

Xcode error: Code signing is required for product type 'Application' in SDK 'iOS 10.0'

To add developer account to Xcode:

  1. Press Cmd ? + , (comma)

  2. Go to Accounts tab

  3. Follow the screen shot below to enable development team:

Step 3

Gson: How to exclude specific fields from Serialization without annotations

Another approach (especially useful if you need to make a decision to exclude a field at runtime) is to register a TypeAdapter with your gson instance. Example below:

Gson gson = new GsonBuilder()
.registerTypeAdapter(BloodPressurePost.class, new BloodPressurePostSerializer())

In the case below, the server would expect one of two values but since they were both ints then gson would serialize them both. My goal was to omit any value that is zero (or less) from the json that is posted to the server.

public class BloodPressurePostSerializer implements JsonSerializer<BloodPressurePost> {

    @Override
    public JsonElement serialize(BloodPressurePost src, Type typeOfSrc, JsonSerializationContext context) {
        final JsonObject jsonObject = new JsonObject();

        if (src.systolic > 0) {
            jsonObject.addProperty("systolic", src.systolic);
        }

        if (src.diastolic > 0) {
            jsonObject.addProperty("diastolic", src.diastolic);
        }

        jsonObject.addProperty("units", src.units);

        return jsonObject;
    }
}

Numpy isnan() fails on an array of floats (from pandas dataframe apply)

On top of @unutbu answer, you could coerce pandas numpy object array to native (float64) type, something along the line

import pandas as pd
pd.to_numeric(df['tester'], errors='coerce')

Specify errors='coerce' to force strings that can't be parsed to a numeric value to become NaN. Column type would be dtype: float64, and then isnan check should work

How to remove focus from single editText

Use the attached code to give the focus to "someone else", this is OK if you have a view where you simply want to dismiss the keyboard and release the focus, you don't really care about who gets it.

Use like this: FocusHelper.releaseFocus(viewToReleaseFocusFrom)

public class FocusHelper {
    public static void releaseFocus(View view) {
        ViewParent parent = view.getParent();
        ViewGroup group = null;
        View child = null;
        while (parent != null) {
            if (parent instanceof ViewGroup) {
                group = (ViewGroup) parent;
                for (int i = 0; i < group.getChildCount(); i++) {
                    child = group.getChildAt(i);
                    if(child != view && child.isFocusable())
                        child.requestFocus();
                }
            }
            parent = parent.getParent();
        }
    }
}

Doc: The method traverses from the child view and up the view tree and looks for the first child to give focus to.

Edit: You can also use the API for this:

View focusableView = v.focusSearch(View.FOCUS_DOWN);
if(focusableView != null) focusableView.requestFocus();

Convert Swift string to array

Martin R answer is the best approach, and as he said, because String conforms the SquenceType protocol, you can also enumerate a string, getting each character on each iteration.

let characters = "Hello"
var charactersArray: [Character] = []

for (index, character) in enumerate(characters) {
    //do something with the character at index
    charactersArray.append(character)
}

println(charactersArray)

Difference between Role and GrantedAuthority in Spring Security

Like others have mentioned, I think of roles as containers for more granular permissions.

Although I found the Hierarchy Role implementation to be lacking fine control of these granular permission.
So I created a library to manage the relationships and inject the permissions as granted authorities in the security context.

I may have a set of permissions in the app, something like CREATE, READ, UPDATE, DELETE, that are then associated with the user's Role.

Or more specific permissions like READ_POST, READ_PUBLISHED_POST, CREATE_POST, PUBLISH_POST

These permissions are relatively static, but the relationship of roles to them may be dynamic.

Example -

@Autowired 
RolePermissionsRepository repository;

public void setup(){
  String roleName = "ROLE_ADMIN";
  List<String> permissions = new ArrayList<String>();
  permissions.add("CREATE");
  permissions.add("READ");
  permissions.add("UPDATE");
  permissions.add("DELETE");
  repository.save(new RolePermissions(roleName, permissions));
}

You may create APIs to manage the relationship of these permissions to a role.

I don't want to copy/paste another answer, so here's the link to a more complete explanation on SO.
https://stackoverflow.com/a/60251931/1308685

To re-use my implementation, I created a repo. Please feel free to contribute!
https://github.com/savantly-net/spring-role-permissions

Passing arguments to require (when loading module)

Based on your comments in this answer, I do what you're trying to do like this:

module.exports = function (app, db) {
    var module = {};

    module.auth = function (req, res) {
        // This will be available 'outside'.
        // Authy stuff that can be used outside...
    };

    // Other stuff...
    module.pickle = function(cucumber, herbs, vinegar) {
        // This will be available 'outside'.
        // Pickling stuff...
    };

    function jarThemPickles(pickle, jar) {
        // This will be NOT available 'outside'.
        // Pickling stuff...

        return pickleJar;
    };

    return module;
};

I structure pretty much all my modules like that. Seems to work well for me.

Using the RUN instruction in a Dockerfile with 'source' does not work

If you're just trying to use pip to install something into the virtualenv, you can modify the PATH env to look in the virtualenv's bin folder first

ENV PATH="/path/to/venv/bin:${PATH}"

Then any pip install commands that follow in the Dockerfile will find /path/to/venv/bin/pip first and use that, which will install into that virtualenv and not the system python.

What to use instead of "addPreferencesFromResource" in a PreferenceActivity?

Instead of using a PreferenceActivity to directly load preferences, use an AppCompatActivity or equivalent that loads a PreferenceFragmentCompat that loads your preferences. It's part of the support library (now Android Jetpack) and provides compatibility back to API 14.

In your build.gradle, add a dependency for the preference support library:

dependencies {
    // ...
    implementation "androidx.preference:preference:1.0.0-alpha1"
}

Note: We're going to assume you have your preferences XML already created.

For your activity, create a new activity class. If you're using material themes, you should extend an AppCompatActivity, but you can be flexible with this:

public class MyPreferencesActivity extends AppCompatActivity {

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.my_preferences_activity)
        if (savedInstanceState == null) {
            getSupportFragmentManager().beginTransaction()
                    .replace(R.id.fragment_container, MyPreferencesFragment())
                    .commitNow()
        }
    }
}

Now for the important part: create a fragment that loads your preferences from XML:

public class MyPreferencesFragment extends PreferenceFragmentCompat {

    @Override
    public void onCreatePreferences(Bundle savedInstanceState, String rootKey) {
        setPreferencesFromResource(R.xml.my_preferences_fragment); // Your preferences fragment
    }
}

For more information, read the Android Developers docs for PreferenceFragmentCompat.

Which MySQL datatype to use for an IP address?

Since IPv4 addresses are 4 byte long, you could use an INT (UNSIGNED) that has exactly 4 bytes:

`ipv4` INT UNSIGNED

And INET_ATON and INET_NTOA to convert them:

INSERT INTO `table` (`ipv4`) VALUES (INET_ATON("127.0.0.1"));
SELECT INET_NTOA(`ipv4`) FROM `table`;

For IPv6 addresses you could use a BINARY instead:

`ipv6` BINARY(16)

And use PHP’s inet_pton and inet_ntop for conversion:

'INSERT INTO `table` (`ipv6`) VALUES ("'.mysqli_real_escape_string(inet_pton('2001:4860:a005::68')).'")'
'SELECT `ipv6` FROM `table`'
$ipv6 = inet_pton($row['ipv6']);

How to remove square brackets in string using regex?

You probably don't even need string substitution for that. If your original string is JSON, try:

js> a="['abc','xyz']"
['abc','xyz']
js> eval(a).join(",")
abc,xyz

Be careful with eval, of course.

sending email via php mail function goes to spam

What we usually do with e-mail, preventing spam-folders as the end destination, is using either Gmail as the smtp server or Mandrill as the smtp server.

How to print the ld(linker) search path

I'm not sure that there is any option for simply printing the full effective search path.

But: the search path consists of directories specified by -L options on the command line, followed by directories added to the search path by SEARCH_DIR("...") directives in the linker script(s). So you can work it out if you can see both of those, which you can do as follows:

If you're invoking ld directly:

  • The -L options are whatever you've said they are.
  • To see the linker script, add the --verbose option. Look for the SEARCH_DIR("...") directives, usually near the top of the output. (Note that these are not necessarily the same for every invocation of ld -- the linker has a number of different built-in default linker scripts, and chooses between them based on various other linker options.)

If you're linking via gcc:

  • You can pass the -v option to gcc so that it shows you how it invokes the linker. In fact, it normally does not invoke ld directly, but indirectly via a tool called collect2 (which lives in one of its internal directories), which in turn invokes ld. That will show you what -L options are being used.
  • You can add -Wl,--verbose to the gcc options to make it pass --verbose through to the linker, to see the linker script as described above.

Simple example of threading in C++

It largely depends on the library you decide to use. For instance, if you use the wxWidgets library, the creation of a thread would look like this:

class RThread : public wxThread {

public:
    RThread()
        : wxThread(wxTHREAD_JOINABLE){
    }
private:
    RThread(const RThread &copy);

public:
    void *Entry(void){
        //Do...

        return 0;
    }

};

wxThread *CreateThread() {
    //Create thread
    wxThread *_hThread = new RThread();

    //Start thread
    _hThread->Create();
    _hThread->Run();

    return _hThread;
}

If your main thread calls the CreateThread method, you'll create a new thread that will start executing the code in your "Entry" method. You'll have to keep a reference to the thread in most cases to join or stop it. More info here: wxThread documentation

Show datalist labels but submit the actual value

Using PHP i've found a quite simple way to do this. Guys, Just Use something like this

<input list="customers" name="customer_id" required class="form-control" placeholder="Customer Name">
            <datalist id="customers">
                <?php 
    $querySnamex = "SELECT * FROM `customer` WHERE fname!='' AND lname!='' order by customer_id ASC";
    $resultSnamex = mysqli_query($con,$querySnamex) or die(mysql_error());

                while ($row_this = mysqli_fetch_array($resultSnamex)) {
                    echo '<option data-value="'.$row_this['customer_id'].'">'.$row_this['fname'].' '.$row_this['lname'].'</option>
                    <input type="hidden" name="customer_id_real" value="'.$row_this['customer_id'].'" id="answerInput-hidden">';
                }

                 ?>
            </datalist>

The Code Above lets the form carry the id of the option also selected.

PHP script to loop through all of the files in a directory?

You can use this code to loop through a directory recursively:

$path = "/home/myhome";
$rdi = new RecursiveDirectoryIterator($path, RecursiveDirectoryIterator::KEY_AS_PATHNAME);
foreach (new RecursiveIteratorIterator($rdi, RecursiveIteratorIterator::SELF_FIRST) as $file => $info) {
    echo $file."\n";
}

EOFException - how to handle?

You catch IOException which also catches EOFException, because it is inherited. If you look at the example from the tutorial they underlined that you should catch EOFException - and this is what they do. To solve you problem catch EOFException before IOException:

try
{
    //...
}
catch(EOFException e) {
    //eof - no error in this case
}
catch(IOException e) {
    //something went wrong
    e.printStackTrace(); 
}

Beside that I don't like data flow control using exceptions - it is not the intended use of exceptions and thus (in my opinion) really bad style.

Redirect form to different URL based on select option element

This can be archived by adding code on the onchange event of the select control.

For Example:

<select onchange="this.options[this.selectedIndex].value && (window.location = this.options[this.selectedIndex].value);">
    <option value="http://gmail.com">Gmail</option>
    <option value="http://youtube.com">Youtube</option>
</select>

Is there a way to get LaTeX to place figures in the same page as a reference to that figure?

You can always add the "!" into your float-options. This way, latex tries really hard to place the figure where you want it (I mostly use [h!tb]), stretching the normal rules of type-setting.

I have found another solution:
Use the float-package. This way you can place the figures where you want them to be.

Combining paste() and expression() functions in plot labels

Use substitute instead.

labNames <- c('xLab','yLab')
plot(c(1:10),
     xlab=substitute(paste(nn, x^2), list(nn=labNames[1])),
     ylab=substitute(paste(nn, y^2), list(nn=labNames[2])))

Create ul and li elements in javascript.

Try out below code snippet:

 var list = [];
 var text;

function update() {
    console.log(list);    

    for (var i = 0; i < list.length; i++) {
       console.log( i );
       var letters;
       var ul = document.getElementById("list");
       var li = document.createElement("li");

       li.appendChild(document.createTextNode(list[i]));
       ul.appendChild(li);

       letters += "<li>"  + list[i] + "</li>";
    }

 document.getElementById("list").innerHTML = letters;

}

function myFunction() {
    text = prompt("enter TODO");  
    list.push(text);
    update();
}   

Change image source with JavaScript

If you will always have the pattern on _b instead of _t you can make it more generic by passing reference to the image itself:

onclick='changeImage(this);'

Then in the function:

function changeImage(img) {
    document.getElementById("img").src = img.src.replace("_t", "_b");
}

Toolbar Navigation Hamburger Icon missing

I had the same problem. Get the ToolBar and then set Navigation icon

final android.support.v7.widget.Toolbar toolbar = (android.support.v7.widget.Toolbar) findViewById(R.id.toolbar);
toolbar.setNavigationIcon(R.drawable.blablabla);

How to bind to a PasswordBox in MVVM

Sorry, but you're doing it wrong.

People should have the following security guideline tattooed on the inside of their eyelids:
Never keep plain text passwords in memory.

The reason the WPF/Silverlight PasswordBox doesn't expose a DP for the Password property is security related.
If WPF/Silverlight were to keep a DP for Password it would require the framework to keep the password itself unencrypted in memory. Which is considered quite a troublesome security attack vector. The PasswordBox uses encrypted memory (of sorts) and the only way to access the password is through the CLR property.

I would suggest that when accessing the PasswordBox.Password CLR property you'd refrain from placing it in any variable or as a value for any property.
Keeping your password in plain text on the client machine RAM is a security no-no.
So get rid of that public string Password { get; set; } you've got up there.

When accessing PasswordBox.Password, just get it out and ship it to the server ASAP. Don't keep the value of the password around and don't treat it as you would any other client machine text. Don't keep clear text passwords in memory.

I know this breaks the MVVM pattern, but you shouldn't ever bind to PasswordBox.Password Attached DP, store your password in the ViewModel or any other similar shenanigans.

If you're looking for an over-architected solution, here's one:
1. Create the IHavePassword interface with one method that returns the password clear text.
2. Have your UserControl implement a IHavePassword interface.
3. Register the UserControl instance with your IoC as implementing the IHavePassword interface.
4. When a server request requiring your password is taking place, call your IoC for the IHavePassword implementation and only than get the much coveted password.

Just my take on it.

-- Justin

How to make a GUI for bash scripts?

You can gtk-server for this. Gtk-server is a program that runs in background and provides text-based interface to allow other programs (including bash scripts) to control it. It has examples for Bash (http://www.gtk-server.org/demo-ipc.bash.txt, http://www.gtk-server.org/demo-fifo.bash.txt)

How to call any method asynchronously in c#

Starting with .Net 4.5 you can use Task.Run to simply start an action:

void Foo(string args){}
...
Task.Run(() => Foo("bar"));

Task.Run vs Task.Factory.StartNew

Error:Cause: unable to find valid certification path to requested target

I got the same issue and I fixed it by changing my firewall setting or you can switch to another network

reasons behind it

when we are running our project run command its configure and check for exiting packages and make proceed to download the new or required package and the packages are stored on non-secure IP/hosting so your firewall will try to protect you and you will get these errors

Getting and removing the first character of a string

See ?substring.

x <- 'hello stackoverflow'
substring(x, 1, 1)
## [1] "h"
substring(x, 2)
## [1] "ello stackoverflow"

The idea of having a pop method that both returns a value and has a side effect of updating the data stored in x is very much a concept from object-oriented programming. So rather than defining a pop function to operate on character vectors, we can make a reference class with a pop method.

PopStringFactory <- setRefClass(
  "PopString",
  fields = list(
    x = "character"  
  ),
  methods = list(
    initialize = function(x)
    {
      x <<- x
    },
    pop = function(n = 1)
    {
      if(nchar(x) == 0)
      {
        warning("Nothing to pop.")
        return("")
      }
      first <- substring(x, 1, n)
      x <<- substring(x, n + 1)
      first
    }
  )
)

x <- PopStringFactory$new("hello stackoverflow")
x
## Reference class object of class "PopString"
## Field "x":
## [1] "hello stackoverflow"
replicate(nchar(x$x), x$pop())
## [1] "h" "e" "l" "l" "o" " " "s" "t" "a" "c" "k" "o" "v" "e" "r" "f" "l" "o" "w"

Mysql error 1452 - Cannot add or update a child row: a foreign key constraint fails

It seems there is some invalid value for the column line 0 that is not a valid foreign key so MySQL cannot set a foreign key constraint for it.

You can follow these steps:

  1. Drop the column which you have tried to set FK constraint for.

  2. Add it again and set its default value as NULL.

  3. Try to set a foreign key constraint for it again.

Implement a simple factory pattern with Spring 3 annotations

Why not add the interface FactoryBean to MyServiceFactory (to tell Spring that it's a factory), add a register(String service, MyService instance) then, have each of the services call:

@Autowired
MyServiceFactory serviceFactory;

@PostConstruct
public void postConstruct() {
    serviceFactory.register(myName, this);
}

This way, you can separate each service provider into modules if necessary, and Spring will automagically pick up any deployed and available service providers.

Toggle visibility property of div

It's better if you check visibility like this: if($('#video-over').is(':visible'))

How to update a plot in matplotlib?

This worked for me:

from matplotlib import pyplot as plt
from IPython.display import clear_output
import numpy as np
for i in range(50):
    clear_output(wait=True)
    y = np.random.random([10,1])
    plt.plot(y)
    plt.show()

Android Studio gradle takes too long to build

I had the same problem, even the gradle build ran for 8 hours and i was worried. But later on i changed the compile sdk version and minimum sdk version in build.gradle file like this.

Older:

android {
compileSdkVersion 25
buildToolsVersion "29.0.2"

defaultConfig {
    applicationId "com.uwebtechnology.salahadmin"
    minSdkVersion 9
    targetSdkVersion 25
}

New (Updated):

android 
{
  compileSdkVersion 28
   buildToolsVersion "25.0.2"

 defaultConfig {
    applicationId "com.uwebtechnology.salahadmin"
    minSdkVersion 15
    targetSdkVersion 28
 }

wp_nav_menu change sub-menu class name?

You don't need to extend the Walker. This will do:

function overrideSubmenuClasses( $classes ) {
    $classes[] = 'myclass1';
    $classes[] = 'myclass2';

    return $classes;
}
add_action('nav_menu_submenu_css_class', 'overrideSubmenuClasses');

Find files containing a given text

find them and grep for the string:

This will find all files of your 3 types in /starting/path and grep for the regular expression '(document\.cookie|setcookie)'. Split over 2 lines with the backslash just for readability...

find /starting/path -type f -name "*.php" -o -name "*.html" -o -name "*.js" | \
 xargs egrep -i '(document\.cookie|setcookie)'

Bash script to check running process

A simple script version of one of Andor's above suggestions:

!/bin/bash

pgrep $1 && echo Running

If the above script is called test.sh then, in order to test, type: test.sh NameOfProcessToCheck

e.g. test.sh php

How to display JavaScript variables in a HTML page without document.write

Add an element to your page (such as a div) and write to that div.

HTML:

<html>
    <header>
        <title>Page Title</title>
    </header>

    <body>
        <div id="myDiv"></div>
    </body>
</html>

jQuery:

$('#myDiv').text('hello world!');

javascript:

document.getElementById('myDiv').innerHTML = 'hello world!';

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

You can use the "ORDER BY DESC" option, then put it back in the original order:

(SELECT * FROM tablename ORDER BY id DESC LIMIT 10) ORDER BY id;

Apache default VirtualHost

I found the answer: I remembered that Apache uses the first block if no other matching block is found, so I've added a block without a serveralias at the top of the blocks:

NameVirtualHost *

<VirtualHost *>
    DocumentRoot /defaultdir/
</VirtualHost>

<VirtualHost *>
    ServerAdmin [email protected]
    DocumentRoot /someOtherDir/
    ServerAlias ip.of.the.server
</VirtualHost>

<VirtualHost *>
    ServerAdmin [email protected]
    DocumentRoot /someroot/
    ServerAlias domain.com *.domain.com
</VirtualHost>

How to start MySQL server on windows xp

maybe

E:\mysql-5.1.39-win32\bin>mysql -u root -p

How to trigger click event on href element

Triggering a click via JavaScript will not open a hyperlink. This is a security measure built into the browser.

See this question for some workarounds, though.

Changing an element's ID with jQuery

<script>
       $(document).ready(function () {
           $('select').attr("id", "newId"); //direct descendant of a
       });
</script>

This could do for all purpose. Just add before your body closing tag and don't for get to add Jquery.min.js

What is the best way to manage a user's session in React?

This not the best way to manage session in react you can use web tokens to encrypt your data that you want save,you can use various number of services available a popular one is JSON web tokens(JWT) with web-tokens you can logout after some time if there no action from the client And after creating the token you can store it in your local storage for ease of access.

jwt.sign({user}, 'secretkey', { expiresIn: '30s' }, (err, token) => {
    res.json({
      token
  });

user object in here is the user data which you want to keep in the session

localStorage.setItem('session',JSON.stringify(token));

AngularJs $http.post() does not send data

I like to use a function to convert objects to post params.

myobject = {'one':'1','two':'2','three':'3'}

Object.toparams = function ObjecttoParams(obj) {
    var p = [];
    for (var key in obj) {
        p.push(key + '=' + encodeURIComponent(obj[key]));
    }
    return p.join('&');
};

$http({
    method: 'POST',
    url: url,
    data: Object.toparams(myobject),
    headers: {'Content-Type': 'application/x-www-form-urlencoded'}
})

How to change href attribute using JavaScript after opening the link in a new window?

Replace

onclick="changeLink();"

by

onclick="changeLink(); return false;"

to cancel its default action

Is a Python dictionary an example of a hash table?

There must be more to a Python dictionary than a table lookup on hash(). By brute experimentation I found this hash collision:

>>> hash(1.1)
2040142438
>>> hash(4504.1)
2040142438

Yet it doesn't break the dictionary:

>>> d = { 1.1: 'a', 4504.1: 'b' }
>>> d[1.1]
'a'
>>> d[4504.1]
'b'

Sanity check:

>>> for k,v in d.items(): print(hash(k))
2040142438
2040142438

Possibly there's another lookup level beyond hash() that avoids collisions between dictionary keys. Or maybe dict() uses a different hash.

(By the way, this in Python 2.7.10. Same story in Python 3.4.3 and 3.5.0 with a collision at hash(1.1) == hash(214748749.8).)

How to select some rows with specific rownames from a dataframe?

You can also use this:

DF[paste0("stu",c(2,3,5,9)), ]

JavaScript - onClick to get the ID of the clicked button

This is improvement of Prateek answer - event is pass by parameter so reply_click not need to use global variable (and as far no body presents this variant)

_x000D_
_x000D_
function reply_click(e) {
  console.log(e.target.id);
}
_x000D_
<button id="1" onClick="reply_click(event)">B1</button>
<button id="2" onClick="reply_click(event)">B2</button>
<button id="3" onClick="reply_click(event)">B3</button>
_x000D_
_x000D_
_x000D_

Starting a node.js server

Run cmd and then run node server.js. In your example, you are trying to use the REPL to run your command, which is not going to work. The ellipsis is node.js expecting more tokens before closing the current scope (you can type code in and run it on the fly here)

How can I dismiss the on screen keyboard?

As in Flutter everything is a widget, I decided to wrap the SystemChannels.textInput.invokeMethod('TextInput.hide'); and the FocusScope.of(context).requestFocus(FocusNode()); approach in a short utility module with a widget and a mixin in it.

With the widget, you can wrap any widget (very convenient when using a good IDE support) with the KeyboardHider widget:

class SimpleWidget extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return KeyboardHider(
      /* Here comes a widget tree that eventually opens the keyboard,
       * but the widget that opened the keyboard doesn't necessarily
       * takes care of hiding it, so we wrap everything in a
       * KeyboardHider widget */
      child: Container(),
    );
  }
}

With the mixin, you can trigger hiding the keyboard from any state or widget upon any interaction:

class SimpleWidget extends StatefulWidget {
  @override
  _SimpleWidgetState createState() => _SimpleWidgetState();
}

class _SimpleWidgetState extends State<SimpleWidget> with KeyboardHiderMixin {
  @override
  Widget build(BuildContext context) {
    return RaisedButton(
      onPressed: () {
        // Hide the keyboard:
        hideKeyboard();
        // Do other stuff, for example:
        // Update the state, make an HTTP request, ...
      },
    );
  }
}

Just create a keyboard_hider.dart file and the widget and mixin are ready to use:

import 'package:flutter/material.dart';
import 'package:flutter/services.dart';

/// Mixin that enables hiding the keyboard easily upon any interaction or logic
/// from any class.
abstract class KeyboardHiderMixin {
  void hideKeyboard({
    BuildContext context,
    bool hideTextInput = true,
    bool requestFocusNode = true,
  }) {
    if (hideTextInput) {
      SystemChannels.textInput.invokeMethod('TextInput.hide');
    }
    if (context != null && requestFocusNode) {
      FocusScope.of(context).requestFocus(FocusNode());
    }
  }
}

/// A widget that can be used to hide the text input that are opened by text
/// fields automatically on tap.
///
/// Delegates to [KeyboardHiderMixin] for hiding the keyboard on tap.
class KeyboardHider extends StatelessWidget with KeyboardHiderMixin {
  final Widget child;

  /// Decide whether to use
  /// `SystemChannels.textInput.invokeMethod('TextInput.hide');`
  /// to hide the keyboard
  final bool hideTextInput;
  final bool requestFocusNode;

  /// One of hideTextInput or requestFocusNode must be true, otherwise using the
  /// widget is pointless as it will not even try to hide the keyboard.
  const KeyboardHider({
    Key key,
    @required this.child,
    this.hideTextInput = true,
    this.requestFocusNode = true,
  })  : assert(child != null),
        assert(hideTextInput || requestFocusNode),
        super(key: key);

  @override
  Widget build(BuildContext context) {
    return GestureDetector(
      behavior: HitTestBehavior.opaque,
      onTap: () {
        hideKeyboard(
          context: context,
          hideTextInput: hideTextInput,
          requestFocusNode: requestFocusNode,
        );
      },
      child: child,
    );
  }
}

Convert timestamp to date in Oracle SQL

I'd go with the following:

Select max(start_ts) 
from db 
where trunc(start_ts) =  date'13-may-2016'

What's the difference between Perl's backticks, system, and exec?

exec

executes a command and never returns. It's like a return statement in a function.

If the command is not found exec returns false. It never returns true, because if the command is found it never returns at all. There is also no point in returning STDOUT, STDERR or exit status of the command. You can find documentation about it in perlfunc, because it is a function.

system

executes a command and your Perl script is continued after the command has finished.

The return value is the exit status of the command. You can find documentation about it in perlfunc.

backticks

like system executes a command and your perl script is continued after the command has finished.

In contrary to system the return value is STDOUT of the command. qx// is equivalent to backticks. You can find documentation about it in perlop, because unlike system and execit is an operator.


Other ways

What is missing from the above is a way to execute a command asynchronously. That means your perl script and your command run simultaneously. This can be accomplished with open. It allows you to read STDOUT/STDERR and write to STDIN of your command. It is platform dependent though.

There are also several modules which can ease this tasks. There is IPC::Open2 and IPC::Open3 and IPC::Run, as well as Win32::Process::Create if you are on windows.

How to get dictionary values as a generic list

You probably want to flatten all of the lists in Values into a single list:

List<MyType> allItems = myDico.Values.SelectMany(c => c).ToList();

Find out where MySQL is installed on Mac OS X

Or use good old "find". For example in order to look for old mysql v5.7:

cd /
find . type -d -name "[email protected]"

Change navbar text color Bootstrap

.nav-link {
color: blue !important;
}

Worked for me. Bootstrap v4.3.1

SELECT INTO Variable in MySQL DECLARE causes syntax error?

You maybe miss the @ symbol before your value,like that select 'test' INTO @myValue;

Remove Fragment Page from ViewPager in Android

For future readers!

Now you can use ViewPager2 for dynamically adding, removing fragment from the viewpager.

Quoting form API reference

ViewPager2 replaces ViewPager, addressing most of its predecessor’s pain-points, including right-to-left layout support, vertical orientation, modifiable Fragment collections, etc.

Take look at MutableCollectionFragmentActivity.kt in googlesample/android-viewpager2 for an example of adding, removing fragments dynamically from the viewpager.


For your information:

Articles:

API reference

Release notes

Samples Repo: https://github.com/googlesamples/android-viewpager2

Multiple markers Google Map API v3 from array of addresses and avoid OVER_QUERY_LIMIT while geocoding on pageLoad

Answer to add multiple markers.

UPDATE (GEOCODE MULTIPLE ADDRESSES)

Here's the working Example Geocoding with multiple addresses.

 <script type="text/javascript" src="http://maps.google.com/maps/api/js?sensor=false">
 </script> 
 <script type="text/javascript">
  var delay = 100;
  var infowindow = new google.maps.InfoWindow();
  var latlng = new google.maps.LatLng(21.0000, 78.0000);
  var mapOptions = {
    zoom: 5,
    center: latlng,
    mapTypeId: google.maps.MapTypeId.ROADMAP
  }
  var geocoder = new google.maps.Geocoder(); 
  var map = new google.maps.Map(document.getElementById("map"), mapOptions);
  var bounds = new google.maps.LatLngBounds();

  function geocodeAddress(address, next) {
    geocoder.geocode({address:address}, function (results,status)
      { 
         if (status == google.maps.GeocoderStatus.OK) {
          var p = results[0].geometry.location;
          var lat=p.lat();
          var lng=p.lng();
          createMarker(address,lat,lng);
        }
        else {
           if (status == google.maps.GeocoderStatus.OVER_QUERY_LIMIT) {
            nextAddress--;
            delay++;
          } else {
                        }   
        }
        next();
      }
    );
  }
 function createMarker(add,lat,lng) {
   var contentString = add;
   var marker = new google.maps.Marker({
     position: new google.maps.LatLng(lat,lng),
     map: map,
           });

  google.maps.event.addListener(marker, 'click', function() {
     infowindow.setContent(contentString); 
     infowindow.open(map,marker);
   });

   bounds.extend(marker.position);

 }
  var locations = [
           'New Delhi, India',
           'Mumbai, India',
           'Bangaluru, Karnataka, India',
           'Hyderabad, Ahemdabad, India',
           'Gurgaon, Haryana, India',
           'Cannaught Place, New Delhi, India',
           'Bandra, Mumbai, India',
           'Nainital, Uttranchal, India',
           'Guwahati, India',
           'West Bengal, India',
           'Jammu, India',
           'Kanyakumari, India',
           'Kerala, India',
           'Himachal Pradesh, India',
           'Shillong, India',
           'Chandigarh, India',
           'Dwarka, New Delhi, India',
           'Pune, India',
           'Indore, India',
           'Orissa, India',
           'Shimla, India',
           'Gujarat, India'
  ];
  var nextAddress = 0;
  function theNext() {
    if (nextAddress < locations.length) {
      setTimeout('geocodeAddress("'+locations[nextAddress]+'",theNext)', delay);
      nextAddress++;
    } else {
      map.fitBounds(bounds);
    }
  }
  theNext();

</script>

As we can resolve this issue with setTimeout() function.

Still we should not geocode known locations every time you load your page as said by @geocodezip

Another alternatives of these are explained very well in the following links:

How To Avoid GoogleMap Geocode Limit!

Geocode Multiple Addresses Tutorial By Mike Williams

Example by Google Developers

Scala Doubles, and Precision

It's actually very easy to handle using Scala f interpolator - https://docs.scala-lang.org/overviews/core/string-interpolation.html

Suppose we want to round till 2 decimal places:

scala> val sum = 1 + 1/4D + 1/7D + 1/10D + 1/13D
sum: Double = 1.5697802197802198

scala> println(f"$sum%1.2f")
1.57

When should I use Lazy<T>?

You typically use it when you want to instantiate something the first time its actually used. This delays the cost of creating it till if/when it's needed instead of always incurring the cost.

Usually this is preferable when the object may or may not be used and the cost of constructing it is non-trivial.

Show message box in case of exception

        try
        {
           // your code
        }
        catch (Exception w)
        {
            MessageDialog msgDialog = new MessageDialog(w.ToString());
        }

Using group by on multiple columns

In simple English from GROUP BY with two parameters what we are doing is looking for similar value pairs and get the count to a 3rd column.

Look at the following example for reference. Here I'm using International football results from 1872 to 2020

+----------+----------------+--------+---+---+--------+---------+-------------------+-----+
|       _c0|             _c1|     _c2|_c3|_c4|     _c5|      _c6|                _c7|  _c8|
+----------+----------------+--------+---+---+--------+---------+-------------------+-----+
|1872-11-30|        Scotland| England|  0|  0|Friendly|  Glasgow|           Scotland|FALSE|
|1873-03-08|         England|Scotland|  4|  2|Friendly|   London|            England|FALSE|
|1874-03-07|        Scotland| England|  2|  1|Friendly|  Glasgow|           Scotland|FALSE|
|1875-03-06|         England|Scotland|  2|  2|Friendly|   London|            England|FALSE|
|1876-03-04|        Scotland| England|  3|  0|Friendly|  Glasgow|           Scotland|FALSE|
|1876-03-25|        Scotland|   Wales|  4|  0|Friendly|  Glasgow|           Scotland|FALSE|
|1877-03-03|         England|Scotland|  1|  3|Friendly|   London|            England|FALSE|
|1877-03-05|           Wales|Scotland|  0|  2|Friendly|  Wrexham|              Wales|FALSE|
|1878-03-02|        Scotland| England|  7|  2|Friendly|  Glasgow|           Scotland|FALSE|
|1878-03-23|        Scotland|   Wales|  9|  0|Friendly|  Glasgow|           Scotland|FALSE|
|1879-01-18|         England|   Wales|  2|  1|Friendly|   London|            England|FALSE|
|1879-04-05|         England|Scotland|  5|  4|Friendly|   London|            England|FALSE|
|1879-04-07|           Wales|Scotland|  0|  3|Friendly|  Wrexham|              Wales|FALSE|
|1880-03-13|        Scotland| England|  5|  4|Friendly|  Glasgow|           Scotland|FALSE|
|1880-03-15|           Wales| England|  2|  3|Friendly|  Wrexham|              Wales|FALSE|
|1880-03-27|        Scotland|   Wales|  5|  1|Friendly|  Glasgow|           Scotland|FALSE|
|1881-02-26|         England|   Wales|  0|  1|Friendly|Blackburn|            England|FALSE|
|1881-03-12|         England|Scotland|  1|  6|Friendly|   London|            England|FALSE|
|1881-03-14|           Wales|Scotland|  1|  5|Friendly|  Wrexham|              Wales|FALSE|
|1882-02-18|Northern Ireland| England|  0| 13|Friendly|  Belfast|Republic of Ireland|FALSE|
+----------+----------------+--------+---+---+--------+---------+-------------------+-----+

And now I'm going to group by similar country(column _c7) and tournament(_c5) value pairs by GROUP BY operation,

SELECT `_c5`,`_c7`,count(*)  FROM res GROUP BY `_c5`,`_c7`

+--------------------+-------------------+--------+
|                 _c5|                _c7|count(1)|
+--------------------+-------------------+--------+
|            Friendly|  Southern Rhodesia|      11|
|            Friendly|            Ecuador|      68|
|African Cup of Na...|           Ethiopia|      41|
|Gold Cup qualific...|Trinidad and Tobago|       9|
|AFC Asian Cup qua...|             Bhutan|       7|
|African Nations C...|              Gabon|       2|
|            Friendly|           China PR|     170|
|FIFA World Cup qu...|             Israel|      59|
|FIFA World Cup qu...|              Japan|      61|
|UEFA Euro qualifi...|            Romania|      62|
|AFC Asian Cup qua...|              Macau|       9|
|            Friendly|        South Sudan|       1|
|CONCACAF Nations ...|           Suriname|       3|
|         Copa Newton|          Argentina|      12|
|            Friendly|        Philippines|      38|
|FIFA World Cup qu...|              Chile|      68|
|African Cup of Na...|         Madagascar|      29|
|FIFA World Cup qu...|       Burkina Faso|      30|
| UEFA Nations League|            Denmark|       4|
|        Atlantic Cup|           Paraguay|       2|
+--------------------+-------------------+--------+

Explanation: The meaning of the first row is there were 11 Friendly tournaments held on Southern Rhodesia in total.

Note: Here it's mandatory to use a counter column in this case.

How to plot a 2D FFT in Matlab?

Here is an example from my HOW TO Matlab page:

close all; clear all;

img   = imread('lena.tif','tif');
imagesc(img)
img   = fftshift(img(:,:,2));
F     = fft2(img);

figure;

imagesc(100*log(1+abs(fftshift(F)))); colormap(gray); 
title('magnitude spectrum');

figure;
imagesc(angle(F));  colormap(gray);
title('phase spectrum');

This gives the magnitude spectrum and phase spectrum of the image. I used a color image, but you can easily adjust it to use gray image as well.

ps. I just noticed that on Matlab 2012a the above image is no longer included. So, just replace the first line above with say

img = imread('ngc6543a.jpg');

and it will work. I used an older version of Matlab to make the above example and just copied it here.

On the scaling factor

When we plot the 2D Fourier transform magnitude, we need to scale the pixel values using log transform to expand the range of the dark pixels into the bright region so we can better see the transform. We use a c value in the equation

s = c log(1+r) 

There is no known way to pre detrmine this scale that I know. Just need to try different values to get on you like. I used 100 in the above example.

enter image description here

Convert a RGB Color Value to a Hexadecimal String

Random ra = new Random();
int r, g, b;
r=ra.nextInt(255);
g=ra.nextInt(255);
b=ra.nextInt(255);
Color color = new Color(r,g,b);
String hex = Integer.toHexString(color.getRGB() & 0xffffff);
if (hex.length() < 6) {
    hex = "0" + hex;
}
hex = "#" + hex;

Filter by Dates in SQL

Well you are trying to compare Date with Nvarchar which is wrong. Should be

Where dates between date1 And date2
-- both date1 & date2 should be date/datetime

If date1,date2 strings; server will convert them to date type before filtering.

Creating a new ArrayList in Java

You can use in Java 8

List<Class> myArray= new ArrayList<>();

How to log Apache CXF Soap Request and Soap Response using Log4j?

Try this code:

EndpointImpl impl = (EndpointImpl)Endpoint.publish(address, implementor);
    impl.getServer().getEndpoint().getInInterceptors().add(new LoggingInInterceptor());
    impl.getServer().getEndpoint().getOutInterceptors().add(new LoggingOutInterceptor());

Inside the logback.xml you need to put the interface name for webservice:

<appender name="FILE" class="ch.qos.logback.classic.sift.SiftingAppender">
    <discriminator
        class="com.progressoft.ecc.integration.logging.ThreadNameDiscriminator">
        <key>threadName</key>
        <defaultValue>unknown</defaultValue>
    </discriminator>
    <filter class="ch.qos.logback.core.filter.EvaluatorFilter">
        <evaluator>
            <expression>logger.contains("InterfaceWebServiceSoap")</expression>
        </evaluator>
        <OnMismatch>DENY</OnMismatch>
        <OnMatch>NEUTRAL</OnMatch>
    </filter>
    <filter class="ch.qos.logback.classic.filter.ThresholdFilter">
        <level>TRACE</level>
    </filter>
    <sift>
        <appender name="FILE-${threadName}"
            class="ch.qos.logback.core.rolling.RollingFileAppender">
            <File>${LOGGING_PATH}/${threadName}.log</File>
            <rollingPolicy class="ch.qos.logback.core.rolling.TimeBasedRollingPolicy">
                <FileNamePattern>${ARCHIVING_PATH}/%d{yyyy-MM-dd}.${threadName}%i.log.zip
                </FileNamePattern>
                <MaxHistory>30</MaxHistory>
                <TimeBasedFileNamingAndTriggeringPolicy
                    class="ch.qos.logback.core.rolling.SizeAndTimeBasedFNATP">
                    <MaxFileSize>50MB</MaxFileSize>
                </TimeBasedFileNamingAndTriggeringPolicy>
            </rollingPolicy>
            <encoder class="ch.qos.logback.classic.encoder.PatternLayoutEncoder">
                <Pattern>%date{dd-MM-yyyy HH:mm:ss.SSS} | %5level | %-60([%logger{53}:%line]): %msg %ex{full} %n</Pattern>
            </encoder>
        </appender>
    </sift>
</appender>

<root>
    <level value="ALL" />
    <appender-ref ref="FILE" />
</root>

Printing HashMap In Java

For me this simple one line worked well:

Arrays.toString(map.entrySet().toArray())

Centering a button vertically in table cell, using Twitter Bootstrap

To fix this, i put this class on the webpage

<style>                        
    td.vcenter {
        vertical-align: middle !important;
        text-align: center !important;
    }
</style>

and this in my TemplateField

<asp:TemplateField ItemStyle-CssClass="vcenter">

as the CSS class points directly to the td (tabledata) element and has the !important statment at the end each setting. It will over rule bootsraps CSS class settings.

Hope it helps

How to respond to clicks on a checkbox in an AngularJS directive?

This is the way I've been doing this sort of stuff. Angular tends to favor declarative manipulation of the dom rather than a imperative one(at least that's the way I've been playing with it).

The markup

<table class="table">
  <thead>
    <tr>
      <th>
        <input type="checkbox" 
          ng-click="selectAll($event)"
          ng-checked="isSelectedAll()">
      </th>
      <th>Title</th>
    </tr>
  </thead>
  <tbody>
    <tr ng-repeat="e in entities" ng-class="getSelectedClass(e)">
      <td>
        <input type="checkbox" name="selected"
          ng-checked="isSelected(e.id)"
          ng-click="updateSelection($event, e.id)">
      </td>
      <td>{{e.title}}</td>
    </tr>
  </tbody>
</table>

And in the controller

var updateSelected = function(action, id) {
  if (action === 'add' && $scope.selected.indexOf(id) === -1) {
    $scope.selected.push(id);
  }
  if (action === 'remove' && $scope.selected.indexOf(id) !== -1) {
    $scope.selected.splice($scope.selected.indexOf(id), 1);
  }
};

$scope.updateSelection = function($event, id) {
  var checkbox = $event.target;
  var action = (checkbox.checked ? 'add' : 'remove');
  updateSelected(action, id);
};

$scope.selectAll = function($event) {
  var checkbox = $event.target;
  var action = (checkbox.checked ? 'add' : 'remove');
  for ( var i = 0; i < $scope.entities.length; i++) {
    var entity = $scope.entities[i];
    updateSelected(action, entity.id);
  }
};

$scope.getSelectedClass = function(entity) {
  return $scope.isSelected(entity.id) ? 'selected' : '';
};

$scope.isSelected = function(id) {
  return $scope.selected.indexOf(id) >= 0;
};

//something extra I couldn't resist adding :)
$scope.isSelectedAll = function() {
  return $scope.selected.length === $scope.entities.length;
};

EDIT: getSelectedClass() expects the entire entity but it was being called with the id of the entity only, which is now corrected

How to force page refreshes or reloads in jQuery?

Or better

window.location.assign("relative or absolute address");

that tends to work best across all browsers and mobile

How to open a link in new tab using angular?

Just add target="_blank" to the

<a mat-raised-button target="_blank" [routerLink]="['/find-post/post', post.postID]"
    class="theme-btn bg-grey white-text mx-2 mb-2">
    Open in New Window
</a>

hasNext in Python iterators?

very interesting question, but this "hasnext" design had been put into leetcode: https://leetcode.com/problems/iterator-for-combination/

here is my implementation:

class CombinationIterator:

def __init__(self, characters: str, combinationLength: int):
    from itertools import combinations
    from collections import deque
    self.iter = combinations(characters, combinationLength)
    self.res = deque()


def next(self) -> str:
    if len(self.res) == 0:
        return ''.join(next(self.iter))
    else:
        return ''.join(self.res.pop())


def hasNext(self) -> bool:
    try:
        self.res.insert(0, next(self.iter))
        return True
    except:
        return len(self.res) > 0

D3.js: How to get the computed width and height for an arbitrary element?

Once I faced with the issue when I did not know which the element currently stored in my variable (svg or html) but I needed to get it width and height. I created this function and want to share it:

function computeDimensions(selection) {
  var dimensions = null;
  var node = selection.node();

  if (node instanceof SVGGraphicsElement) { // check if node is svg element
    dimensions = node.getBBox();
  } else { // else is html element
    dimensions = node.getBoundingClientRect();
  }
  console.log(dimensions);
  return dimensions;
}

Little demo in the hidden snippet below. We handle click on the blue div and on the red svg circle with the same function.

_x000D_
_x000D_
var svg = d3.select('svg')
  .attr('width', 50)
  .attr('height', 50);

function computeDimensions(selection) {
    var dimensions = null;
  var node = selection.node();

  if (node instanceof SVGElement) {
    dimensions = node.getBBox();
  } else {
    dimensions = node.getBoundingClientRect();
  }
  console.clear();
  console.log(dimensions);
  return dimensions;
}

var circle = svg
    .append("circle")
    .attr("r", 20)
    .attr("cx", 30)
    .attr("cy", 30)
    .attr("fill", "red")
    .on("click", function() { computeDimensions(circle); });
    
var div = d3.selectAll("div").on("click", function() { computeDimensions(div) });
_x000D_
* {
  margin: 0;
  padding: 0;
  border: 0;
}

body {
  background: #ffd;
}

.div {
  display: inline-block;
  background-color: blue;
  margin-right: 30px;
  width: 30px;
  height: 30px;
}
_x000D_
<h3>
  Click on blue div block or svg circle
</h3>
<svg></svg>
<div class="div"></div>
<script src="https://cdnjs.cloudflare.com/ajax/libs/d3/4.11.0/d3.min.js"></script>
_x000D_
_x000D_
_x000D_

insert data into database with codeigniter

function saveProfile(){
    $firstname = $this->input->post('firstname');
    $lastname = $this->input->post('lastname');
    $post_data = array('firstname'=> $firstname,'lastname'=>$lastname);
    $this->db->insert('posts',$post_data);
    return $this->db->insert_id(); 
}

Bash ignoring error for a particular command

Instead of "returning true", you can also use the "noop" or null utility (as referred in the POSIX specs) : and just "do nothing". You'll save a few letters. :)

#!/usr/bin/env bash
set -e
man nonexistentghing || :
echo "It's ok.."

How to calculate probability in a normal distribution given mean & standard deviation?

I wrote this program to do the math for you. Just enter in the summary statistics. No need to provide an array:

One-Sample Z-Test for a Population Proportion:

To do this for mean rather than proportion, change the formula for z accordingly

EDIT:
Here is the content from the link:

import scipy.stats as stats
import math

def one_sample_ztest_pop_proportion(tail, p, pbar, n, alpha):
    #Calculate test stat

    sigma = math.sqrt((p*(1-p))/(n))
    z = round((pbar - p) / sigma, 2)

    if tail == 'lower':
        pval = round(stats.norm(p, sigma).cdf(pbar),4)
        print("Results for a lower tailed z-test: ")


    elif tail == 'upper':
        pval = round(1 - stats.norm(p, sigma).cdf(pbar),4)
        print("Results for an upper tailed z-test: ")


    elif tail == 'two':
        pval = round(stats.norm(p, sigma).cdf(pbar)*2,4)
        print("Results for a two tailed z-test: ")


    #Print test results
    print("Test statistic = {}".format(z))   
    print("P-value = {}".format(pval))
    print("Confidence = {}".format(alpha))

    #Compare p-value to confidence level
    if pval <= alpha:
        print("{} <=  {}. Reject the null hypothesis.".format(pval, alpha))
    else:
        print("{} > {}. Do not reject the null hypothesis.".format(pval, alpha))


#one_sample_ztest_pop_proportion('upper', .20, .25, 400, .05)

#one_sample_ztest_pop_proportion('two', .64, .52, 100, .05)

How to change color of the back arrow in the new material theme?

try this

public void enableActionBarHomeButton(AppCompatActivity appCompatActivity, int colorId){

    final Drawable upArrow = ContextCompat.getDrawable(appCompatActivity, R.drawable.abc_ic_ab_back_material);
    upArrow.setColorFilter(ContextCompat.getColor(appCompatActivity, colorId), PorterDuff.Mode.SRC_ATOP);

    android.support.v7.app.ActionBar mActionBar = appCompatActivity.getSupportActionBar();
    mActionBar.setHomeAsUpIndicator(upArrow);
    mActionBar.setHomeButtonEnabled(true);
    mActionBar.setDisplayHomeAsUpEnabled(true);
}

function call:

enableActionBarHomeButton(this, R.color.white);

urllib2 and json

This is what worked for me:

import json
import requests
url = 'http://xxx.com'
payload = {'param': '1', 'data': '2', 'field': '4'}
headers = {'content-type': 'application/json'}
r = requests.post(url, data = json.dumps(payload), headers = headers)

Delete files or folder recursively on Windows CMD

For completely wiping a folder with native commands and getting a log on what's been done.

here's an unusual way to do it :

let's assume we want to clear the d:\temp dir

mkdir d:\empty
robocopy /mir d:\empty d:\temp
rmdir d:\empty

How to limit the maximum value of a numeric field in a Django model?

You can use Django's built-in validators

from django.db.models import IntegerField, Model
from django.core.validators import MaxValueValidator, MinValueValidator

class CoolModelBro(Model):
    limited_integer_field = IntegerField(
        default=1,
        validators=[
            MaxValueValidator(100),
            MinValueValidator(1)
        ]
     )

Edit: When working directly with the model, make sure to call the model full_clean method before saving the model in order to trigger the validators. This is not required when using ModelForm since the forms will do that automatically.

Easy way to export multiple data.frame to multiple Excel worksheets

Many good answers here, but some of them are a little dated. If you want to add further worksheets to a single file then this is the approach I find works for me. For clarity, here is the workflow for openxlsx version 4.0

# Create a blank workbook
OUT <- createWorkbook()

# Add some sheets to the workbook
addWorksheet(OUT, "Sheet 1 Name")
addWorksheet(OUT, "Sheet 2 Name")

# Write the data to the sheets
writeData(OUT, sheet = "Sheet 1 Name", x = dataframe1)
writeData(OUT, sheet = "Sheet 2 Name", x = dataframe2)

# Export the file
saveWorkbook(OUT, "My output file.xlsx")

EDIT

I've now trialled a few other answers, and I actually really like @Syed's. It doesn't exploit all the functionality of openxlsx but if you want a quick-and-easy export method then that's probably the most straightforward.

AngularJS custom filter function

Here's an example of how you'd use filter within your AngularJS JavaScript (rather than in an HTML element).

In this example, we have an array of Country records, each containing a name and a 3-character ISO code.

We want to write a function which will search through this list for a record which matches a specific 3-character code.

Here's how we'd do it without using filter:

$scope.FindCountryByCode = function (CountryCode) {
    //  Search through an array of Country records for one containing a particular 3-character country-code.
    //  Returns either a record, or NULL, if the country couldn't be found.
    for (var i = 0; i < $scope.CountryList.length; i++) {
        if ($scope.CountryList[i].IsoAlpha3 == CountryCode) {
            return $scope.CountryList[i];
        };
    };
    return null;
};

Yup, nothing wrong with that.

But here's how the same function would look, using filter:

$scope.FindCountryByCode = function (CountryCode) {
    //  Search through an array of Country records for one containing a particular 3-character country-code.
    //  Returns either a record, or NULL, if the country couldn't be found.

    var matches = $scope.CountryList.filter(function (el) { return el.IsoAlpha3 == CountryCode; })

    //  If 'filter' didn't find any matching records, its result will be an array of 0 records.
    if (matches.length == 0)
        return null;

    //  Otherwise, it should've found just one matching record
    return matches[0];
};

Much neater.

Remember that filter returns an array as a result (a list of matching records), so in this example, we'll either want to return 1 record, or NULL.

Hope this helps.

ToList()-- does it create a new list?

I don't see anywhere in the documentation that ToList() is always guaranteed to return a new list. If an IEnumerable is a List, it may be more efficient to check for this and simply return the same List.

The worry is that sometimes you may want to be absolutely sure that the returned List is != to the original List. Because Microsoft doesn't document that ToList will return a new List, we can't be sure (unless someone found that documentation). It could also change in the future, even if it works now.

new List(IEnumerable enumerablestuff) is guaranteed to return a new List. I would use this instead.

Taskkill /f doesn't kill a process

For me, the way it worked is I have to kill the parent process. Figure the parent process out and kill it

taskkill /IM "parent_process_name.exe" /T /F

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

If you're using SQL Server 2005 and up, you can also use this:

SELECT 
    t.NAME AS TableName,
    i.name as indexName,
    p.[Rows],
    sum(a.total_pages) as TotalPages, 
    sum(a.used_pages) as UsedPages, 
    sum(a.data_pages) as DataPages,
    (sum(a.total_pages) * 8) / 1024 as TotalSpaceMB, 
    (sum(a.used_pages) * 8) / 1024 as UsedSpaceMB, 
    (sum(a.data_pages) * 8) / 1024 as DataSpaceMB
FROM 
    sys.tables t
INNER JOIN      
    sys.indexes i ON t.OBJECT_ID = i.object_id
INNER JOIN 
    sys.partitions p ON i.object_id = p.OBJECT_ID AND i.index_id = p.index_id
INNER JOIN 
    sys.allocation_units a ON p.partition_id = a.container_id
WHERE 
    t.NAME NOT LIKE 'dt%' AND
    i.OBJECT_ID > 255 AND   
    i.index_id <= 1
GROUP BY 
    t.NAME, i.object_id, i.index_id, i.name, p.[Rows]
ORDER BY 
    object_name(i.object_id) 

In my opinion, it's easier to handle than the sp_msforeachtable output.

How to highlight cell if value duplicate in same column for google spreadsheet?

Try this:

  1. Select the whole column
  2. Click Format
  3. Click Conditional formatting
  4. Click Add another rule (or edit the existing/default one)
  5. Set Format cells if to: Custom formula is
  6. Set value to: =countif(A:A,A1)>1 (or change A to your chosen column)
  7. Set the formatting style.
  8. Ensure the range applies to your column (e.g., A1:A100).
  9. Click Done

Anything written in the A1:A100 cells will be checked, and if there is a duplicate (occurs more than once) then it'll be coloured.

For locales using comma (,) as a decimal separator, the argument separator is most likely a semi-colon (;). That is, try: =countif(A:A;A1)>1, instead.

For multiple columns, use countifs.

How to change FontSize By JavaScript?

Please never do this in real projects:

_x000D_
_x000D_
document.getElementById("span").innerHTML = "String".fontsize(25);
_x000D_
<span id="span"></span>
_x000D_
_x000D_
_x000D_

Class Not Found Exception when running JUnit test

Pls check if you have added junit4 as dependency.

e.g

<dependency>
    <groupId>junit</groupId>
    <artifactId>junit</artifactId>
    <version>4.11</version>
    <scope>test</scope>
</dependency>

Dynamically create checkbox with JQuery from text input

<div id="cblist">
    <input type="checkbox" value="first checkbox" id="cb1" /> <label for="cb1">first checkbox</label>
</div>

<input type="text" id="txtName" />
<input type="button" value="ok" id="btnSave" />

<script type="text/javascript">
$(document).ready(function() {
    $('#btnSave').click(function() {
        addCheckbox($('#txtName').val());
    });
});

function addCheckbox(name) {
   var container = $('#cblist');
   var inputs = container.find('input');
   var id = inputs.length+1;

   $('<input />', { type: 'checkbox', id: 'cb'+id, value: name }).appendTo(container);
   $('<label />', { 'for': 'cb'+id, text: name }).appendTo(container);
}
</script>

OpenSSL Command to check if a server is presenting a certificate

In my case the ssl certificate was not configured for all sites (only for the www version which the non-www version redirected to). I am using Laravel forge and the Nginx Boilerplate config

I had the following config for my nginx site:

/etc/nginx/sites-available/timtimer.at

server {
    listen [::]:80;
    listen 80;
    server_name timtimer.at www.timtimer.at;

    include h5bp/directive-only/ssl.conf;

    # and redirect to the https host (declared below)
    # avoiding http://www -> https://www -> https:// chain.
    return 301 https://www.timtimer.at$request_uri;
}

server {
    listen [::]:443 ssl spdy;
    listen 443 ssl spdy;

    # listen on the wrong host
    server_name timtimer.at;

    ### ERROR IS HERE ###
    # You eighter have to include the .crt and .key here also (like below)
    # or include it in the below included ssl.conf like suggested by H5BP

    include h5bp/directive-only/ssl.conf;

    # and redirect to the www host (declared below)
    return 301 https://www.timtimer.at$request_uri;
}

server {
    listen [::]:443 ssl spdy;
    listen 443 ssl spdy;

    server_name www.timtimer.at;

    include h5bp/directive-only/ssl.conf;

    # Path for static files
    root /home/forge/default/public;

    # FORGE SSL (DO NOT REMOVE!)
    ssl_certificate /etc/nginx/ssl/default/2658/server.crt;
    ssl_certificate_key /etc/nginx/ssl/default/2658/server.key;

    # ...

    # Include the basic h5bp config set
    include h5bp/basic.conf;
}

So after moving (cutting & pasting) the following part to the /etc/nginx/h5bp/directive-only/ssl.conf file everything worked as expected:

# FORGE SSL (DO NOT REMOVE!)
ssl_certificate /etc/nginx/ssl/default/2658/server.crt;
ssl_certificate_key /etc/nginx/ssl/default/2658/server.key;

So it is not enough to have the keys specified only for the www version even, if you only call the www version directly!

Node.js - How to send data from html to express

Using http.createServer is very low-level and really not useful for creating web applications as-is.

A good framework to use on top of it is Express, and I would seriously suggest using it. You can install it using npm install express.

When you have, you can create a basic application to handle your form:

var express = require('express');
var bodyParser = require('body-parser');
var app     = express();

//Note that in version 4 of express, express.bodyParser() was
//deprecated in favor of a separate 'body-parser' module.
app.use(bodyParser.urlencoded({ extended: true })); 

//app.use(express.bodyParser());

app.post('/myaction', function(req, res) {
  res.send('You sent the name "' + req.body.name + '".');
});

app.listen(8080, function() {
  console.log('Server running at http://127.0.0.1:8080/');
});

You can make your form point to it using:

<form action="http://127.0.0.1:8080/myaction" method="post">

The reason you can't run Node on port 80 is because there's already a process running on that port (which is serving your index.html). You could use Express to also serve static content, like index.html, using the express.static middleware.

Android Min SDK Version vs. Target SDK Version

If you are making apps that require dangerous permissions and set targetSDK to 23 or above you should be careful. If you do not check permissions on runtime you will get a SecurityException and if you are using code inside a try block, for example open camera, it can be hard to detect error if you do not check logcat.

What's the whole point of "localhost", hosts and ports at all?

Localhost generally refers to the machine you're looking at. On most machines localhost resolves to the IP address 127.0.0.1 which is the loopback address.