Programs & Examples On #Marshalling

Marshalling is the process of transforming the memory representation of an object to a data format suitable for storage or transmission

Convert Python ElementTree to string

If you just need this for debugging to see how the XML looks like, then instead of print(xml.etree.ElementTree.tostring(e)) you can use dump like this:

xml.etree.ElementTree.dump(e)

And this works both with Element and ElementTree objects as e, so there should be no need for getroot.

The documentation of dump says:

xml.etree.ElementTree.dump(elem)

Writes an element tree or element structure to sys.stdout. This function should be used for debugging only.

The exact output format is implementation dependent. In this version, it’s written as an ordinary XML file.

elem is an element tree or an individual element.

Changed in version 3.8: The dump() function now preserves the attribute order specified by the user.

Is it possible to get all arguments of a function as single object inside that function?

Similar answer to Gunnar, with more complete example: You can even transparently return the whole thing:

function dumpArguments(...args) {
  for (var i = 0; i < args.length; i++)
    console.log(args[i]);
  return args;
}

dumpArguments("foo", "bar", true, 42, ["yes", "no"], { 'banana': true });

Output:

foo
bar
true
42
["yes","no"]
{"banana":true}

https://codepen.io/fnocke/pen/mmoxOr?editors=0010

What is the difference between Serialization and Marshaling?

Both do one thing in common - that is serializing an Object. Serialization is used to transfer objects or to store them. But:

  • Serialization: When you serialize an object, only the member data within that object is written to the byte stream; not the code that actually implements the object.
  • Marshalling: Term Marshalling is used when we talk about passing Object to remote objects(RMI). In Marshalling Object is serialized(member data is serialized) + Codebase is attached.

So Serialization is part of Marshalling.

CodeBase is information that tells the receiver of Object where the implementation of this object can be found. Any program that thinks it might ever pass an object to another program that may not have seen it before must set the codebase, so that the receiver can know where to download the code from, if it doesn't have the code available locally. The receiver will, upon deserializing the object, fetch the codebase from it and load the code from that location.

What is "String args[]"? parameter in main method Java

When you finish your code, you will turn it into a file with the extension .java, which can be run by double clicking it, but also throughout a console (terminal on a mac, cmd.exe on windows) which lets the user do many things. One thing is they can see console messages (System.out.print or System.out.println) which they can't see if they double click. Another thing they can do is specify parameters, so normally you would use the line

java -jar MyCode.jar

after navigating to the folder of the program with

cd C:My/Code/Location

on windows or

cd My/Code/Location

on Mac (notice that mac is less clunky) to run code, but to specify parameters you would use

java -jar MyCode.jar parameter1 parameter2

These parameters stored in the args array, which you can use in your program is you want to allow the user to control special parameters such as what file to use or how much memory the program can have. If you want to know how to use an array, you could probably find a topic on this site or just google it. Note that any number of parameters can be used.

How do I create a Bash alias?

It works for me on macOS Majave

You can do a few simple steps:

1) open terminal

2) sudo nano /.bash_profile

3) add your aliases, as example:

# some aliases
alias ll='ls -alF'
alias la='ls -A'
alias eb="sudo nano ~/.bash_profile && source ~/.bash_profile"
#docker aliases
alias d='docker'
alias dc='docker-compose'
alias dnax="docker rm $(docker ps -aq)"
#git aliases
alias g='git'
alias new="git checkout -b"
alias last="git log -2"
alias gg='git status'
alias lg="git log --pretty=format:'%h was %an, %ar, message: %s' --graph"
alias nah="git reset --hard && git clean -df"
alias squash="git rebase -i HEAD~2"

4) source /.bash_profile

Done. Use and enjoy!

Count number of days between two dates

(end_date - start_date)/1000/60/60/24

any one have best practice please comment below

jQuery check if attr = value

jQuery's attr method returns the value of the attribute:

The .attr() method gets the attribute value for only the first element in the matched set. To get the value for each element individually, use a looping construct such as jQuery's .each() or .map() method.

All you need is:

$('html').attr('lang') == 'fr-FR'

However, you might want to do a case-insensitive match:

$('html').attr('lang').toLowerCase() === 'fr-fr'

jQuery's val method returns the value of a form element.

The .val() method is primarily used to get the values of form elements such as input, select and textarea. In the case of <select multiple="multiple"> elements, the .val() method returns an array containing each selected option; if no option is selected, it returns null.

alternative to "!is.null()" in R

You may be better off working out what value type your function or code accepts, and asking for that:

if (is.integer(aVariable))
{
  do whatever
}

This may be an improvement over isnull, because it provides type checking. On the other hand, it may reduce the genericity of your code.

Alternatively, just make the function you want:

is.defined = function(x)!is.null(x)

Unpacking a list / tuple of pairs into two lists / tuples

>>> source_list = ('1','a'),('2','b'),('3','c'),('4','d')
>>> list1, list2 = zip(*source_list)
>>> list1
('1', '2', '3', '4')
>>> list2
('a', 'b', 'c', 'd')

Edit: Note that zip(*iterable) is its own inverse:

>>> list(source_list) == zip(*zip(*source_list))
True

When unpacking into two lists, this becomes:

>>> list1, list2 = zip(*source_list)
>>> list(source_list) == zip(list1, list2)
True

Addition suggested by rocksportrocker.

How can I install Apache Ant on Mac OS X?

Ant is already installed on some older versions of Mac OS X, so you should run ant -version to test if it is installed before attempting to install it.

If it is not already installed, then your best bet is to install Homebrew (brew install ant) or MacPorts (sudo port install apache-ant), and use those tools to install Apache Ant.

Alternatively, though I would highly advise using Homebrew or MacPorts instead, you can install Apache Ant manually. To do so, you would need to:

  1. Decompress the .tar.gz file.
  2. Optionally put it somewhere.
  3. Put the "bin" subdirectory in your path.

The commands that you would need, assuming apache-ant-1.8.1-bin.tar.gz (replace 1.8.1 with the actual version) were still in your Downloads directory, would be the following (explanatory comments included):

cd ~/Downloads # Let's get into your downloads folder.
tar -xvzf apache-ant-1.8.1-bin.tar.gz # Extract the folder
sudo mkdir -p /usr/local # Ensure that /usr/local exists
sudo cp -rf apache-ant-1.8.1-bin /usr/local/apache-ant # Copy it into /usr/local
# Add the new version of Ant to current terminal session
export PATH=/usr/local/apache-ant/bin:"$PATH"
# Add the new version of Ant to future terminal sessions
echo 'export PATH=/usr/local/apache-ant/bin:"$PATH"' >> ~/.profile
# Verify new version of ant
ant -version

PyCharm import external library

I wanted to add an import path, for another project elsewhere in my workspace. MacOS Catalina 10.15.5 PyCharm Community 2020.1.1

PyCharm - Preferences - Project interpreter - Cog symbol - Show All

At the bottom of that dialog, it shows 5 buttons: Plus, Minus, Pencil, Funnel, and Directory tree.

Click Directory tree. You can now use the Plus button in the new dialog to add your 'external library' search path.

If successful, you should now see the directory name in the "External Libraries" pane in the Project panel.

Didn't Java once have a Pair class?

Many 3rd party libraries have their versions of Pair, but Java has never had such a class. The closest is the inner interface java.util.Map.Entry, which exposes an immutable key property and a possibly mutable value property.

Where is the documentation for the values() method of Enum?

The method is implicitly defined (i.e. generated by the compiler).

From the JLS:

In addition, if E is the name of an enum type, then that type has the following implicitly declared static methods:

/**
* Returns an array containing the constants of this enum 
* type, in the order they're declared.  This method may be
* used to iterate over the constants as follows:
*
*    for(E c : E.values())
*        System.out.println(c);
*
* @return an array containing the constants of this enum 
* type, in the order they're declared
*/
public static E[] values();

/**
* Returns the enum constant of this type with the specified
* name.
* The string must match exactly an identifier used to declare
* an enum constant in this type.  (Extraneous whitespace 
* characters are not permitted.)
* 
* @return the enum constant with the specified name
* @throws IllegalArgumentException if this enum type has no
* constant with the specified name
*/
public static E valueOf(String name);

What is the purpose of "pip install --user ..."?

Why not just put an executable somewhere in my $PATH

~/.local/bin directory is theoretically expected to be in your $PATH.

According to these people it's a bug not adding it in the $PATH when using systemd.

This answer explains it more extensively.

But even if your distro includes the ~/.local/bin directory to the $PATH, it might be in the following form (inside ~/.profile):

if [ -d "$HOME/.local/bin" ] ; then
    PATH="$HOME/.local/bin:$PATH"
fi

which would require you to logout and login again, if the directory was not there before.

How to get logged-in user's name in Access vba?

In a Form, Create a text box, with in text box properties select data tab

Default value =CurrentUser()

Current source "select table field name"

It will display current user log on name in text box / label as well as saves the user name in the table field

Dynamically Changing log4j log level

If you would want to change the logging level of all the loggers use the below method. This will enumerate over all the loggers and change the logging level to given level. Please make sure that you DO NOT have log4j.appender.loggerName.Threshold=DEBUG property set in your log4j.properties file.

public static void changeLogLevel(Level level) {
    Enumeration<?> loggers = LogManager.getCurrentLoggers();
    while(loggers.hasMoreElements()) {
        Logger logger = (Logger) loggers.nextElement();
        logger.setLevel(level);
    }
}

Date difference in minutes in Python

In Other ways to get difference between date;

import dateutil.parser
import datetime

timeDifference = current_date - dateutil.parser.parse(last_sent_date)
time_difference_in_minutes = (int(timeDifference.days) * 24 * 60) + int((timeDifference.seconds) / 60)

Thanks

How to change value of object which is inside an array using JavaScript or jQuery?

Here i am using angular js. In javascript you can use for loop to find.

    if($scope.bechval>0 &&$scope.bechval!=undefined)
    {

                angular.forEach($scope.model.benhmarkghamlest, function (val, key) {
                $scope.model.benhmarkghamlest[key].bechval = $scope.bechval;

            });
    }
    else {
        alert("Please sepecify Bechmark value");
    }

Is there a C# case insensitive equals operator?

Try this:

string.Equals(a, b, StringComparison.CurrentCultureIgnoreCase);

MySQL Error 1093 - Can't specify target table for update in FROM clause

This is what I did for updating a Priority column value by 1 if it is >=1 in a table and in its WHERE clause using a subquery on same table to make sure that at least one row contains Priority=1 (because that was the condition to be checked while performing update) :


UPDATE My_Table
SET Priority=Priority + 1
WHERE Priority >= 1
AND (SELECT TRUE FROM (SELECT * FROM My_Table WHERE Priority=1 LIMIT 1) as t);

I know it's a bit ugly but it does works fine.

Django model "doesn't declare an explicit app_label"

In my case, I was trying the same import in manage.py shell. The shell was messed up with the updated db. I mean, I forgot to restart my shell after updating the DB.

To resolve the issue, I had to stop the shell by the following command:

>>> exit()

then restart the shell by the following command:

$ python3 manage.py shell

Hope this will help somebody like me.

Rendering HTML in a WebView with custom CSS

I assume that your style-sheet "style.css" is already located in the assets-folder

  1. load the web-page with jsoup:

    doc = Jsoup.connect("http://....").get();
    
  2. remove links to external style-sheets:

    // remove links to external style-sheets
    doc.head().getElementsByTag("link").remove();
    
  3. set link to local style-sheet:

    // set link to local stylesheet
    // <link rel="stylesheet" type="text/css" href="style.css" />
    doc.head().appendElement("link").attr("rel", "stylesheet").attr("type", "text/css").attr("href", "style.css");
    
  4. make string from jsoup-doc/web-page:

    String htmldata = doc.outerHtml();
    
  5. display web-page in webview:

    WebView webview = new WebView(this);
    setContentView(webview);
    webview.loadDataWithBaseURL("file:///android_asset/.", htmlData, "text/html", "UTF-8", null);
    

How to monitor network calls made from iOS Simulator

A free and open source proxy tool that runs easily on a Mac is mitmproxy.

The website includes links to a Mac binary, as well as the source code on Github.

The docs contain a very helpful intro to loading a cert into your test device to view HTTPS traffic.

Not quite as GUI-tastic as Charles, but it does everything I need and its free and maintained. Good stuff, and pretty straightforward if you've used some command line tools before.

UPDATE: I just noticed on the website that mitmproxy is available as a homebrew install. Couldn't be easier.

HTML embed autoplay="false", but still plays automatically

the below codes helped me with the same problem. Let me know if it helped.

<!DOCTYPE html>
<html>
<body>


<audio controls>

<source src="YOUR AUDIO FILE" type="audio/mpeg">
Your browser does not support the audio element.
</audio>



</body>
</html>

How to initialize a variable of date type in java?

To parse a Date from a String you can choose which format you would like it to have. For example:

public Date StringToDate(String s){

    Date result = null;
    try{
        SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        result  = dateFormat.parse(s);
    }

    catch(ParseException e){
        e.printStackTrace();

    }
    return result ;
}

If you would like to use this method now, you will have to use something like this

Date date = StringToDate("2015-12-06 17:03:00");

For more explanation you should check out http://docs.oracle.com/javase/7/docs/api/java/text/SimpleDateFormat.html

Why should we NOT use sys.setdefaultencoding("utf-8") in a py script?

  • The first danger lies in reload(sys).

    When you reload a module, you actually get two copies of the module in your runtime. The old module is a Python object like everything else, and stays alive as long as there are references to it. So, half of the objects will be pointing to the old module, and half to the new one. When you make some change, you will never see it coming when some random object doesn't see the change:

    (This is IPython shell)
    
    In [1]: import sys
    
    In [2]: sys.stdout
    Out[2]: <colorama.ansitowin32.StreamWrapper at 0x3a2aac8>
    
    In [3]: reload(sys)
    <module 'sys' (built-in)>
    
    In [4]: sys.stdout
    Out[4]: <open file '<stdout>', mode 'w' at 0x00000000022E20C0>
    
    In [11]: import IPython.terminal
    
    In [14]: IPython.terminal.interactiveshell.sys.stdout
    Out[14]: <colorama.ansitowin32.StreamWrapper at 0x3a9aac8>
    
  • Now, sys.setdefaultencoding() proper

    All that it affects is implicit conversion str<->unicode. Now, utf-8 is the sanest encoding on the planet (backward-compatible with ASCII and all), the conversion now "just works", what could possibly go wrong?

    Well, anything. And that is the danger.

    • There may be some code that relies on the UnicodeError being thrown for non-ASCII input, or does the transcoding with an error handler, which now produces an unexpected result. And since all code is tested with the default setting, you're strictly on "unsupported" territory here, and no-one gives you guarantees about how their code will behave.
    • The transcoding may produce unexpected or unusable results if not everything on the system uses UTF-8 because Python 2 actually has multiple independent "default string encodings". (Remember, a program must work for the customer, on the customer's equipment.)
      • Again, the worst thing is you will never know that because the conversion is implicit -- you don't really know when and where it happens. (Python Zen, koan 2 ahoy!) You will never know why (and if) your code works on one system and breaks on another. (Or better yet, works in IDE and breaks in console.)

How to find the Target *.exe file of *.appref-ms

The app is stored in %LocalAppData% in your %UserProfile%. So the full path could be:

C:\Users\username\AppData\Local\GitHub

What is the difference between `let` and `var` in swift?

One more difference, which I've encountered in other languages for Constants is : can't initialise the constant(let) for later , should initialise as you're about to declare the constant.

For instance :

let constantValue : Int // Compile error - let declarations require an initialiser expression

Variable

var variableValue : Int // No issues 

Difference between Key, Primary Key, Unique Key and Index in MySQL

Unique Keys: The columns in which no two rows are similar

Primary Key: Collection of minimum number of columns which can uniquely identify every row in a table (i.e. no two rows are similar in all the columns constituting primary key). There can be more than one primary key in a table. If there exists a unique-key then it is primary key (not "the" primary key) in the table. If there does not exist a unique key then more than one column values will be required to identify a row like (first_name, last_name, father_name, mother_name) can in some tables constitute primary key.

Index: used to optimize the queries. If you are going to search or sort the results on basis of some column many times (eg. mostly people are going to search the students by name and not by their roll no.) then it can be optimized if the column values are all "indexed" for example with a binary tree algorithm.

What is the difference among col-lg-*, col-md-* and col-sm-* in Bootstrap?

well it's used to tell bootstrap how many columns are to be placed in a row depending on the screen size-

col-xs-2

would show only 2 columns in a row in extra small(xs) screen, in the same way as sm defines a small screen, md(medium sized), lg(large sized), but according to bootstrap smaller first rule, if you mention

xs-col-2 md-col-4

then 2 columns would be shown in every row for screen sizes from xs upto sm(included) and changes when it gets next size i.e. for md up to lg(included) for a better understanding of screen sizes try running them in various screen modes in chrome's developer mode(ctr+shift+i) and try various pixels or devices

How to search for string in an array

Another option would be use a dictionary instead of an array:

Dim oNames As Object
Set oNames = CreateObject("Scripting.Dictionary")
'You could if need be create this automatically from an existing Array
'The 1 is just a dummy value, we just want the names as keys
oNames.Add "JOHN", 1
oNames.Add "BOB", 1
oNames.Add "JAMES", 1
oNames.Add "PHILIP", 1

As this would then get you a one-liner of

oNames.Exists("JOHN")

The advantage a dictionary provides is exact matching over partial matching from Filter. Say if you have the original list of names in an Array, but were looking for "JO" or "PHIL" who were actually two new people in addition to the four we started with. In this case, Filter(oNAMES, "JO") will match "JOHN" which may not be desired. With a dictionary, it won't.

Retina displays, high-res background images

Do I need to double the size of the .box div to 400px by 400px to match the new high res background image

No, but you do need to set the background-size property to match the original dimensions:

@media (-webkit-min-device-pixel-ratio: 2), 
(min-resolution: 192dpi) { 

    .box{
        background:url('images/[email protected]') no-repeat top left;
        background-size: 200px 200px;
    }
}

EDIT

To add a little more to this answer, here is the retina detection query I tend to use:

@media
only screen and (-webkit-min-device-pixel-ratio: 2),
only screen and (   min--moz-device-pixel-ratio: 2),
only screen and (     -o-min-device-pixel-ratio: 2/1),
only screen and (        min-device-pixel-ratio: 2),
only screen and (                min-resolution: 192dpi),
only screen and (                min-resolution: 2dppx) { 

}

- Source

NB. This min--moz-device-pixel-ratio: is not a typo. It is a well documented bug in certain versions of Firefox and should be written like this in order to support older versions (prior to Firefox 16). - Source


As @LiamNewmarch mentioned in the comments below, you can include the background-size in your shorthand background declaration like so:

.box{
    background:url('images/[email protected]') no-repeat top left / 200px 200px;
}

However, I personally would not advise using the shorthand form as it is not supported in iOS <= 6 or Android making it unreliable in most situations.

How to list processes attached to a shared memory segment in linux?

I wrote a tool called who_attach_shm.pl, it parses /proc/[pid]/maps to get the information. you can download it from github

sample output:

shm attach process list, group by shm key
##################################################################

0x2d5feab4:    /home/curu/mem_dumper /home/curu/playd
0x4e47fc6c:    /home/curu/playd
0x77da6cfe:    /home/curu/mem_dumper /home/curu/playd /home/curu/scand

##################################################################
process shm usage
##################################################################
/home/curu/mem_dumper [2]:    0x2d5feab4 0x77da6cfe
/home/curu/playd [3]:    0x2d5feab4 0x4e47fc6c 0x77da6cfe
/home/curu/scand [1]:    0x77da6cfe

MySQL - how to front pad zip code with "0"?

CHAR(5)

or

MEDIUMINT (5) UNSIGNED ZEROFILL

The first takes 5 bytes per zip code.

The second takes only 3 bytes per zip code. The ZEROFILL option is necessary for zip codes with leading zeros.

SQL MERGE statement to update data

If you need just update your records in energydata based on data in temp_energydata, assuming that temp_enerydata doesn't contain any new records, then try this:

UPDATE e SET e.kWh = t.kWh
  FROM energydata e INNER JOIN 
       temp_energydata t ON e.webmeterID = t.webmeterID AND 
                            e.DateTime = t.DateTime

Here is working sqlfiddle

But if temp_energydata contains new records and you need to insert it to energydata preferably with one statement then you should definitely go with the answer that Bacon Bits gave.

Python convert decimal to hex

To get a pure hex value this might be useful. It's based on Joe's answer:

def gethex(decimal):
    return hex(decimal)[2:]

How to get all subsets of a set? (powerset)

I have found the following algorithm very clear and simple:

def get_powerset(some_list):
    """Returns all subsets of size 0 - len(some_list) for some_list"""
    if len(some_list) == 0:
        return [[]]

    subsets = []
    first_element = some_list[0]
    remaining_list = some_list[1:]
    # Strategy: get all the subsets of remaining_list. For each
    # of those subsets, a full subset list will contain both
    # the original subset as well as a version of the subset
    # that contains first_element
    for partial_subset in get_powerset(remaining_list):
        subsets.append(partial_subset)
        subsets.append(partial_subset[:] + [first_element])

    return subsets

Another way one can generate the powerset is by generating all binary numbers that have n bits. As a power set the amount of number with n digits is 2 ^ n. The principle of this algorithm is that an element could be present or not in a subset as a binary digit could be one or zero but not both.

def power_set(items):
    N = len(items)
    # enumerate the 2 ** N possible combinations
    for i in range(2 ** N):
        combo = []
        for j in range(N):
            # test bit jth of integer i
            if (i >> j) % 2 == 1:
                combo.append(items[j])
        yield combo

I found both algorithms when I was taking MITx: 6.00.2x Introduction to Computational Thinking and Data Science, and I consider it is one of the easiest algorithms to understand I have seen.

Python Matplotlib Y-Axis ticks on Right Side of Plot

Use ax.yaxis.tick_right()

for example:

from matplotlib import pyplot as plt

f = plt.figure()
ax = f.add_subplot(111)
ax.yaxis.tick_right()
plt.plot([2,3,4,5])
plt.show()

enter image description here

Get input type="file" value when it has multiple files selected

The files selected are stored in an array: [input].files

For example, you can access the items

// assuming there is a file input with the ID `my-input`...
var files = document.getElementById("my-input").files;

for (var i = 0; i < files.length; i++)
{
 alert(files[i].name);
}

For jQuery-comfortable people, it's similarly easy

// assuming there is a file input with the ID `my-input`...
var files = $("#my-input")[0].files;

for (var i = 0; i < files.length; i++)
{
 alert(files[i].name);
}

How can I create a memory leak in Java?

Theoretically you can't. Java memory model prevents it. However, because Java has to be implemented, there are some caveats you can use. Depends on what you can use:

  • If you can use native, you can allocate memory that you don not relinquish later.

  • If that is not available, there is a dirty little secret about java that not much people know. You can ask for a direct access array that is not managed by GC, and therefor can be easily used to make a memory leak. This is provided by DirectByteBuffer (http://download.oracle.com/javase/1.5.0/docs/api/java/nio/ByteBuffer.html#allocateDirect(int)).

  • If you can't use any of those, you still can make a memory leak by tricking the GC. The JVM is implemented using a Generational garbage collection. What this means is that the heap is divided into areas: young, adults and elders. An object when its created starts at the young area. As he is used more and more, he progresses into adults up to elders. An object that reaches the eldery area most likely will not be garbaged collected. You cannot be sure that an object is leaked and if you ask for a stop and clean GC it may clean it but for a long period of time he will be leaked. More info at (http://java.sun.com/docs/hotspot/gc1.4.2/faq.html)

  • Also, class objects are not required to be GC'ed. Might me a way to do it.

Vim autocomplete for Python

This can be a good option if you want python completion as well as other languages. https://github.com/Valloric/YouCompleteMe

The python completion is jedi based same as jedi-vim.

NodeJS: How to decode base64 encoded string back to binary?

As of Node.js v6.0.0 using the constructor method has been deprecated and the following method should instead be used to construct a new buffer from a base64 encoded string:

var b64string = /* whatever */;
var buf = Buffer.from(b64string, 'base64'); // Ta-da

For Node.js v5.11.1 and below

Construct a new Buffer and pass 'base64' as the second argument:

var b64string = /* whatever */;
var buf = new Buffer(b64string, 'base64'); // Ta-da

If you want to be clean, you can check whether from exists :

if (typeof Buffer.from === "function") {
    // Node 5.10+
    buf = Buffer.from(b64string, 'base64'); // Ta-da
} else {
    // older Node versions, now deprecated
    buf = new Buffer(b64string, 'base64'); // Ta-da
}

Excel cell value as string won't store as string

Use Range("A1").Text instead of .Value

post comment edit:
Why?
Because the .Text property of Range object returns what is literally visible in the spreadsheet, so if you cell displays for example i100l:25he*_92 then <- Text will return exactly what it in the cell including any formatting.
The .Value and .Value2 properties return what's stored in the cell under the hood excluding formatting. Specially .Value2 for date types, it will return the decimal representation.

If you want to dig deeper into the meaning and performance, I just found this article which seems like a good guide

another edit
Here you go @Santosh
type in (MANUALLY) the values from the DEFAULT (col A) to other columns
Do not format column A at all
Format column B as Text
Format column C as Date[dd/mm/yyyy]
Format column D as Percentage
Dont Format column A, Format B as TEXT, C as Date, D as Percentage
now,
paste this code in a module

Sub main()

    Dim ws As Worksheet, i&, j&
    Set ws = Sheets(1)
    For i = 3 To 7
        For j = 1 To 4
            Debug.Print _
                    "row " & i & vbTab & vbTab & _
                    Cells(i, j).Text & vbTab & _
                    Cells(i, j).Value & vbTab & _
                    Cells(i, j).Value2
        Next j
    Next i
End Sub

and Analyse the output! Its really easy and there isn't much more i can do to help :)

            .TEXT              .VALUE             .VALUE2
row 3       hello             hello               hello
row 3       hello             hello               hello
row 3       hello             hello               hello
row 3       hello             hello               hello
row 4       1                 1                   1
row 4       1                 1                   1
row 4       01/01/1900        31/12/1899          1
row 4       1.00%             0.01                0.01
row 5       helo1$$           helo1$$             helo1$$
row 5       helo1$$           helo1$$             helo1$$
row 5       helo1$$           helo1$$             helo1$$
row 5       helo1$$           helo1$$             helo1$$
row 6       63                63                  63
row 6       =7*9              =7*9                =7*9
row 6       03/03/1900        03/03/1900          63
row 6       6300.00%          63                  63
row 7       29/05/2013        29/05/2013          41423
row 7       29/05/2013        29/05/2013          29/05/2013
row 7       29/05/2013        29/05/2013          41423
row 7       29/05/2013%       29/05/2013%         29/05/2013%

WebSockets protocol vs HTTP

For the TL;DR, here are 2 cents and a simpler version for your questions:

  1. WebSockets provides these benefits over HTTP:

    • Persistent stateful connection for the duration of the connection
    • Low latency: near-real-time communication between server/client due to no overhead of reestablishing connections for each request as HTTP requires.
    • Full duplex: both server and client can send/receive simultaneously
  2. WebSocket and HTTP protocol have been designed to solve different problems, I.E. WebSocket was designed to improve bi-directional communication whereas HTTP was designed to be stateless, distributed using a request/response model. Other than sharing the ports for legacy reasons (firewall/proxy penetration), there isn't much common ground to combine them into one protocol.

How to copy the first few lines of a giant file, and add a line of text at the end of it using some Linux commands?

I am assuming what you are trying to achieve is to insert a line after the first few lines of of a textfile.

head -n10 file.txt >> newfile.txt
echo "your line >> newfile.txt
tail -n +10 file.txt >> newfile.txt

If you don't want to rest of the lines from the file, just skip the tail part.

How do you set your pythonpath in an already-created virtualenv?

It's already answered here -> Is my virtual environment (python) causing my PYTHONPATH to break?

UNIX/LINUX

Add "export PYTHONPATH=/usr/local/lib/python2.0" this to ~/.bashrc file and source it by typing "source ~/.bashrc" OR ". ~/.bashrc".

WINDOWS XP

1) Go to the Control panel 2) Double click System 3) Go to the Advanced tab 4) Click on Environment Variables

In the System Variables window, check if you have a variable named PYTHONPATH. If you have one already, check that it points to the right directories. If you don't have one already, click the New button and create it.

PYTHON CODE

Alternatively, you can also do below your code:-

import sys
sys.path.append("/home/me/mypy") 

How to export query result to csv in Oracle SQL Developer?

FYI to anyone who runs into problems, there is a bug in CSV timestamp export that I just spent a few hours working around. Some fields I needed to export were of type timestamp. It appears the CSV export option even in the current version (3.0.04 as of this posting) fails to put the grouping symbols around timestamps. Very frustrating since spaces in the timestamps broke my import. The best workaround I found was to write my query with a TO_CHAR() on all my timestamps, which yields the correct output, albeit with a little more work. I hope this saves someone some time or gets Oracle on the ball with their next release.

Remove characters from a String in Java

String id = id.substring(0,id.length()-4)

Consider defining a bean of type 'package' in your configuration [Spring-Boot]

Moving the Springbootapplication(application.java) file to another package resolved the issue for me. Keep it separate from the controllers and repositories.

Can't use SURF, SIFT in OpenCV

The following page provides a relatively good guide that requires few corrections : https://cv-tricks.com/how-to/installation-of-opencv-4-1-0-in-windows-10-from-source/

On step 8, when you are choosing generator for the project (tool used for building), don't forget to specify x64 in the second field if you need it. If you don't, you will get LNK1112 error, which is a linker error caused if one module is created with the x64 compiler, and another module is created with the x86 compiler.

Next, when choosing flags in step 9, don't forget to tick the "OPENCV_ENABLE_NONFREE", and set the path for flag "OPENCV_EXTRA_MODULES_PATH" flag. The path must be set to "modules" folder in opencv-contrib-python.

So you need both opencv, and opencv-contrib-python in order to use SIFT and SURF.

How to Save Console.WriteLine Output to Text File

do you want to write code for that or just use command-line feature 'command redirection' as follows:

app.exe >> output.txt

as demonstrated here: http://discomoose.org/2006/05/01/output-redirection-to-a-file-from-the-windows-command-line/ (Archived at archive.org)

EDIT: link dead, here's another example: http://pcsupport.about.com/od/commandlinereference/a/redirect-command-output-to-file.htm

CSS Classes & SubClasses

Your problem seems to be a missing space between your two classes in the CSS:

.area1.item
{
    color:red;
}

Should be

.area1 .item
{
    color:red;
}

How do you run a single query through mysql from the command line?

mysql -u <user> -p -e "select * from schema.table"

How to format a duration in java? (e.g format H:MM:SS)

using this func

private static String strDuration(long duration) {
    int ms, s, m, h, d;
    double dec;
    double time = duration * 1.0;

    time = (time / 1000.0);
    dec = time % 1;
    time = time - dec;
    ms = (int)(dec * 1000);

    time = (time / 60.0);
    dec = time % 1;
    time = time - dec;
    s = (int)(dec * 60);

    time = (time / 60.0);
    dec = time % 1;
    time = time - dec;
    m = (int)(dec * 60);

    time = (time / 24.0);
    dec = time % 1;
    time = time - dec;
    h = (int)(dec * 24);
    
    d = (int)time;
    
    return (String.format("%d d - %02d:%02d:%02d.%03d", d, h, m, s, ms));
}

Retrieving Dictionary Value Best Practices

I imagine that trygetvalue is doing something more like:

if(myDict.ReallyOptimisedVersionofContains(someKey))
{ 
  someVal = myDict[someKey];
  return true;
}
return false;

So hopefully no try/catch anywhere.

I think it is just a method of convenience really. I generally use it as it saves a line of code or two.

Initialize class fields in constructor or at declaration?

Assuming the type in your example, definitely prefer to initialize fields in the constructor. The exceptional cases are:

  • Fields in static classes/methods
  • Fields typed as static/final/et al

I always think of the field listing at the top of a class as the table of contents (what is contained herein, not how it is used), and the constructor as the introduction. Methods of course are chapters.

Javascript Date - set just the date, ignoring time?

If you don't mind creating an extra date object, you could try:

var tempDate = new Date(parseInt(item.timestamp, 10));
var visitDate = new Date (tempDate.getUTCFullYear(), tempDate.getUTCMonth(), tempDate.getUTCDate());

I do something very similar to get a date of the current month without the time.

How to append contents of multiple files into one file

Another option, for those of you who still stumble upon this post like I did, is to use find -exec:

find . -type f -name '*.txt' -exec cat {} + >> output.file

In my case, I needed a more robust option that would look through multiple subdirectories so I chose to use find. Breaking it down:

find .

Look within the current working directory.

-type f

Only interested in files, not directories, etc.

-name '*.txt'

Whittle down the result set by name

-exec cat {} +

Execute the cat command for each result. "+" means only 1 instance of cat is spawned (thx @gniourf_gniourf)

 >> output.file

As explained in other answers, append the cat-ed contents to the end of an output file.

How do you implement a circular buffer in C?

@Adam Rosenfield's solution, although correct, could be implemented with a more lightweight circular_buffer structure that does not invlove count and capacity.

The structure could only hold the following 4 pointers:

  • buffer: Points to the start of the buffer in memory.
  • buffer_end: Points to the end of the buffer in memory.
  • head: Points to the end of stored data.
  • tail: Points to the start of stored data.

We could keep the sz attribute to allow the parametrisation of the unit of storage.

Both the count and the capacity values should be derive-able using the above pointers.

Capacity

capacity is straight forward, as it can be derived by dividing the distance between the buffer_end pointer and the buffer pointer by the unit of storage sz (snippet below is pseudocode):

capacity = (buffer_end - buffer) / sz

Count

For count though, things get a bit more complicated. For example, there is no way to determine whether the buffer is empty or full, in the scenario of head and tail pointing to the same location.

To tackle that, the buffer should allocate memory for an additional element. For example, if the desired capacity of our circular buffer is 10 * sz, then we need to allocate 11 * sz.

Capacity formula will then become (snippet below is pseudocode):

capacity_bytes = buffer_end - buffer - sz
capacity = capacity_bytes / sz

This extra element semantic allows us to construct conditions that evaluate whether the buffer is empty or full.

Empty state conditions

In order for the buffer to be empty, the head pointer points to the same location as the tail pointer:

head == tail

If the above evaluates to true, the buffer is empty.

Full state conditions

In order for the buffer to be full, the head pointer should be 1 element behind the tail pointer. Thus, the space needed to cover in order to jump from the head location to the tail location should be equal to 1 * sz.

if tail is larger that head:

tail - head == sz

If the above evaluates to true, the buffer is full.

if head is larger that tail:

  1. buffer_end - head returns the space to jump from the head to the end of the buffer.
  2. tail - buffer returns the space needed to jump from the start of the buffer to the `tail.
  3. Adding the above 2 should equal to the space needed to jump from the head to the tail
  4. The space derived in step 3, shold not be more than 1 * sz
(buffer_end - head) + (tail - buffer) == sz
=> buffer_end - buffer - head + tail == sz
=> buffer_end - buffer - sz == head - tail
=> head - tail == buffer_end - buffer - sz
=> head - tail == capacity_bytes

If the above evaluates to true, the buffer is full.

In practice

Modifying @Adam Rosenfield's to use the above circular_buffer structure:

#include <string.h>

#define CB_SUCCESS 0        /* CB operation was successful */
#define CB_MEMORY_ERROR 1   /* Failed to allocate memory */
#define CB_OVERFLOW_ERROR 2 /* CB is full. Cannot push more items. */
#define CB_EMPTY_ERROR 3    /* CB is empty. Cannot pop more items. */

typedef struct circular_buffer {
  void *buffer;
  void *buffer_end;
  size_t sz;
  void *head;
  void *tail;
} circular_buffer;

int cb_init(circular_buffer *cb, size_t capacity, size_t sz) {
  const int incremented_capacity = capacity + 1; // Add extra element to evaluate count
  cb->buffer = malloc(incremented_capacity * sz);
  if (cb->buffer == NULL)
    return CB_MEMORY_ERROR;
  cb->buffer_end = (char *)cb->buffer + incremented_capacity * sz;
  cb->sz = sz;
  cb->head = cb->buffer;
  cb->tail = cb->buffer;
  return CB_SUCCESS;
}

int cb_free(circular_buffer *cb) {
  free(cb->buffer);
  return CB_SUCCESS;
}

const int _cb_length(circular_buffer *cb) {
  return (char *)cb->buffer_end - (char *)cb->buffer;
}

int cb_push_back(circular_buffer *cb, const void *item) {
  const int buffer_length = _cb_length(cb);
  const int capacity_length = buffer_length - cb->sz;

  if ((char *)cb->tail - (char *)cb->head == cb->sz ||
      (char *)cb->head - (char *)cb->tail == capacity_length)
    return CB_OVERFLOW_ERROR;

  memcpy(cb->head, item, cb->sz);

  cb->head = (char*)cb->head + cb->sz;
  if(cb->head == cb->buffer_end)
    cb->head = cb->buffer;

  return CB_SUCCESS;
}

int cb_pop_front(circular_buffer *cb, void *item) {
  if (cb->head == cb->tail)
    return CB_EMPTY_ERROR;

  memcpy(item, cb->tail, cb->sz);

  cb->tail = (char*)cb->tail + cb->sz;
  if(cb->tail == cb->buffer_end)
    cb->tail = cb->buffer;

  return CB_SUCCESS;
}

Create a new TextView programmatically then display it below another TextView

public View recentView;

public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        //Create a relative layout and add a button
        relativeLayout = new RelativeLayout(this);
        btn = new Button(this);
        btn.setId((int)System.currentTimeMillis());
        recentView = btn;
        btn.setText("Click me");
        relativeLayout.addView(btn);


        setContentView(relativeLayout);

        btn.setOnClickListener(new View.OnClickListener() {

            @Overr ide
            public void onClick(View view) {

                //Create a textView, set a random ID and position it below the most recently added view
                textView = new TextView(ActivityName.this);
                textView.setId((int)System.currentTimeMillis());
                layoutParams = new RelativeLayout.LayoutParams(LayoutParams.WRAP_CONTENT,LayoutParams.WRAP_CONTENT);
                layoutParams.addRule(RelativeLayout.BELOW, recentView.getId());
                textView.setText("Time: "+System.currentTimeMillis());
                relativeLayout.addView(textView, layoutParams);
                recentView = textView;
            }
        });
    }

This can be modified to display each element of a String array in different TextViews.

How can I disable the UITableView selection?

At least as of iOS 6, you can override methods in your custom cell to prevent the blue highlight. No other interaction is disabled or affected. All three must be overridden.

- (void) setHighlighted:(BOOL)highlighted
{
}

- (void) setHighlighted:(BOOL)highlighted animated:(BOOL)animated
{
}

- (void) setSelected:(BOOL)selected animated:(BOOL)animated
{
}

jQuery event for images loaded

For same-origin images, you could use:

$.get('http://www.your_domain.com/image.jpg', imgLoaded);

function imgLoaded(){
    console.log(this, 'loaded');
}

How to justify a single flexbox item (override justify-content)

AFAIK there is no property for that in the specs, but here is a trick I’ve been using: set the container element ( the one with display:flex ) to justify-content:space-around Then add an extra element between the first and second item and set it to flex-grow:10 (or some other value that works with your setup)

Edit: if the items are tightly aligned it's a good idea to add flex-shrink: 10; to the extra element as well, so the layout will be properly responsive on smaller devices.

C#: Waiting for all threads to complete

I was tying to figure out how to do this but i could not get any answers from google. I know this is an old thread but here was my solution:

Use the following class:

class ThreadWaiter
    {
        private int _numThreads = 0;
        private int _spinTime;

        public ThreadWaiter(int SpinTime)
        {
            this._spinTime = SpinTime;
        }

        public void AddThreads(int numThreads)
        {
            _numThreads += numThreads;
        }

        public void RemoveThread()
        {
            if (_numThreads > 0)
            {
                _numThreads--;
            }
        }

        public void Wait()
        {
            while (_numThreads != 0)
            {
                System.Threading.Thread.Sleep(_spinTime);
            }
        }
    }
  1. Call Addthreads(int numThreads) before executing a thread(s).
  2. Call RemoveThread() after each one has completed.
  3. Use Wait() at the point that you want to wait for all the threads to complete before continuing

Cross Domain Form POSTing

Same origin policy has nothing to do with sending request to another url (different protocol or domain or port).

It is all about restricting access to (reading) response data from another url. So JavaScript code within a page can post to arbitrary domain or submit forms within that page to anywhere (unless the form is in an iframe with different url).

But what makes these POST requests inefficient is that these requests lack antiforgery tokens, so are ignored by the other url. Moreover, if the JavaScript tries to get that security tokens, by sending AJAX request to the victim url, it is prevented to access that data by Same Origin Policy.

A good example: here

And a good documentation from Mozilla: here

Check if string contains only letters in javascript

With /^[a-zA-Z]/ you only check the first character:

  • ^: Assert position at the beginning of the string
  • [a-zA-Z]: Match a single character present in the list below:
    • a-z: A character in the range between "a" and "z"
    • A-Z: A character in the range between "A" and "Z"

If you want to check if all characters are letters, use this instead:

/^[a-zA-Z]+$/.test(str);
  • ^: Assert position at the beginning of the string
  • [a-zA-Z]: Match a single character present in the list below:
    • +: Between one and unlimited times, as many as possible, giving back as needed (greedy)
    • a-z: A character in the range between "a" and "z"
    • A-Z: A character in the range between "A" and "Z"
  • $: Assert position at the end of the string (or before the line break at the end of the string, if any)

Or, using the case-insensitive flag i, you could simplify it to

/^[a-z]+$/i.test(str);

Or, since you only want to test, and not match, you could check for the opposite, and negate it:

!/[^a-z]/i.test(str);

How to programmatically empty browser cache?

_x000D_
_x000D_
//The code below should be put in the "js" folder with the name "clear-browser-cache.js"_x000D_
_x000D_
(function () {_x000D_
    var process_scripts = false;_x000D_
    var rep = /.*\?.*/,_x000D_
    links = document.getElementsByTagName('link'),_x000D_
    scripts = document.getElementsByTagName('script');_x000D_
    var value = document.getElementsByName('clear-browser-cache');_x000D_
    for (var i = 0; i < value.length; i++) {_x000D_
        var val = value[i],_x000D_
            outerHTML = val.outerHTML;_x000D_
        var check = /.*value="true".*/;_x000D_
        if (check.test(outerHTML)) {_x000D_
            process_scripts = true;_x000D_
        }_x000D_
    }_x000D_
    for (var i = 0; i < links.length; i++) {_x000D_
        var link = links[i],_x000D_
        href = link.href;_x000D_
        if (rep.test(href)) {_x000D_
            link.href = href + '&' + Date.now();_x000D_
        }_x000D_
        else {_x000D_
            link.href = href + '?' + Date.now();_x000D_
        }_x000D_
    }_x000D_
    if (process_scripts) {_x000D_
        for (var i = 0; i < scripts.length; i++) {_x000D_
            var script = scripts[i],_x000D_
            src = script.src;_x000D_
            if (src !== "") {_x000D_
                if (rep.test(src)) {_x000D_
                    script.src = src + '&' + Date.now();_x000D_
                }_x000D_
                else {_x000D_
                    script.src = src + '?' + Date.now();_x000D_
                }_x000D_
            }_x000D_
        }_x000D_
    }_x000D_
})();
_x000D_
At the end of the tah head, place the line at the code below_x000D_
_x000D_
    < script name="clear-browser-cache" src='js/clear-browser-cache.js' value="true" >< /script >
_x000D_
_x000D_
_x000D_

Get values from label using jQuery

Firstly, I don't think spaces for an id is valid.

So i'd change the id to not include spaces.

<label year="2010" month="6" id="currentMonth"> June &nbsp;2010</label>

then the jquery code is simple (keep in mind, its better to fetch the jquery object once and use over and over agian)

var label = $('#currentMonth');
var month = label.attr('month');
var year = label.attr('year');
var text = label.text();

How do I install Composer on a shared hosting?

I have successfully installed Composer (and Laravel) on my shared hosting with only FTP access:

  1. Download and install PHPShell on a shared hosting

  2. In PHPShell's config.php add a user and an alias:

    php = "php -d suhosin.executor.include.whitelist=phar"

  3. Log in to PHPShell and type: curl -sS https://getcomposer.org/installer | php

  4. When successfully installed, run Composer: php composer.phar

Linux command to list all available commands and aliases

The problem is that the tab-completion is searching your path, but all commands are not in your path.

To find the commands in your path using bash you could do something like :

for x in echo $PATH | cut -d":" -f1; do ls $x; done

How do I check if a column is empty or null in MySQL?

As defined by the SQL-92 Standard, when comparing two strings of differing widths, the narrower value is right-padded with spaces to make it is same width as the wider value. Therefore, all string values that consist entirely of spaces (including zero spaces) will be deemed to be equal e.g.

'' = ' ' IS TRUE
'' = '  ' IS TRUE
' ' = '  ' IS TRUE
'  ' = '      ' IS TRUE
etc

Therefore, this should work regardless of how many spaces make up the some_col value:

SELECT * 
  FROM T
 WHERE some_col IS NULL 
       OR some_col = ' ';

or more succinctly:

SELECT * 
  FROM T
 WHERE NULLIF(some_col, ' ') IS NULL;

How to get the date and time values in a C program?

I'm getting the following error when compiling Adam Rosenfield's code on Windows. It turns out few things are missing from the code.

Error (Before)

C:\C\Codes>gcc time.c -o time
time.c:3:12: error: initializer element is not constant
 time_t t = time(NULL);
            ^
time.c:4:16: error: initializer element is not constant
 struct tm tm = *localtime(&t);
                ^
time.c:6:8: error: expected declaration specifiers or '...' before string constant
 printf("now: %d-%d-%d %d:%d:%d\n", tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday, tm.tm_hour, tm.tm_min, tm.tm_sec);
        ^
time.c:6:36: error: expected declaration specifiers or '...' before 'tm'
 printf("now: %d-%d-%d %d:%d:%d\n", tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday, tm.tm_hour, tm.tm_min, tm.tm_sec);
                                    ^
time.c:6:55: error: expected declaration specifiers or '...' before 'tm'
 printf("now: %d-%d-%d %d:%d:%d\n", tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday, tm.tm_hour, tm.tm_min, tm.tm_sec);
                                                       ^
time.c:6:70: error: expected declaration specifiers or '...' before 'tm'
 printf("now: %d-%d-%d %d:%d:%d\n", tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday, tm.tm_hour, tm.tm_min, tm.tm_sec);
                                                                      ^
time.c:6:82: error: expected declaration specifiers or '...' before 'tm'
 printf("now: %d-%d-%d %d:%d:%d\n", tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday, tm.tm_hour, tm.tm_min, tm.tm_sec);
                                                                                  ^
time.c:6:94: error: expected declaration specifiers or '...' before 'tm'
 printf("now: %d-%d-%d %d:%d:%d\n", tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday, tm.tm_hour, tm.tm_min, tm.tm_sec);
                                                                                              ^
time.c:6:105: error: expected declaration specifiers or '...' before 'tm'
 printf("now: %d-%d-%d %d:%d:%d\n", tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday, tm.tm_hour, tm.tm_min, tm.tm_sec);
                                                                                                         ^
C:\C\Codes>

Solution

C:\C\Codes>more time.c
#include <stdio.h>
#include <time.h>

int main()
{
        time_t t = time(NULL);
        struct tm tm = *localtime(&t);

        printf("now: %d-%d-%d %d:%d:%d\n", tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday, tm.tm_hour, tm.tm_min, tm.tm_sec);
}

C:\C\Codes>

Compiling

C:\C\Codes>gcc time.c -o time

C:\C\Codes>    

Final Output

C:\C\Codes>time
now: 2018-3-11 15:46:36

C:\C\Codes>

I hope this will helps others too

Creating executable files in Linux

It's really not that big of a deal. You could just make a script with the single command:

chmod a+x *.pl

And run the script after creating a perl file. Alternatively, you could open a file with a command like this:

touch filename.pl && chmod a+x filename.pl && vi filename.pl # choose your favorite editor

How to use IntelliJ IDEA to find all unused code?

After you've run the Inspect by Name, select all the locations, and make use of the Apply quick fixes to all the problems drop-down, and use either (or both) of Delete unused parameter(s) and Safe Delete.

Don't forget to hit Do Refactor afterwards.

Then you'll need to run another analysis, as the refactored code will no doubt reveal more unused declarations.

Apply quick fixes to all the problems

Apache Prefork vs Worker MPM

Apache's Multi-Processing Modules (MPMs) are responsible for binding to network ports on the machine, accepting requests, and dispatching children to handle the requests (http://httpd.apache.org/docs/2.2/mpm.html).

They're like any other Apache module, except that just one and only one MPM must be loaded into the server at any time. MPMs are chosen during configuration and compiled into the server by using the argument --with-mpm=NAME with the configure script where NAME is the name of the desired MPM.

Apache will use a default MPM for each operating system unless a different one is choosen at compile-time (for instance on Windows mpm_winnt is used by default). Here's the list of operating systems and their default MPMs:

  • BeOS beos
  • Netware mpm_netware
  • OS/2 mpmt_os2
  • Unix/Linux prefork (update for Apache version = 2.4: prefork, worker, or event, depending on platform capabilities)
  • Windows mpm_winnt

To check what modules are compiled into the server use the command-line option -l (here is the documentation). For instance on a Windows installation you might get something like:

> httpd -l
Compiled in modules:
  core.c
  mod_win32.c
  mpm_winnt.c
  http_core.c
  mod_so.c

As of version 2.2 this is the list of available core features and MPM modules:

  • core - Core Apache HTTP Server features that are always available
  • mpm_common - A collection of directives that are implemented by more than one multi-processing module (MPM)
  • beos - This Multi-Processing Module is optimized for BeOS.
  • event - An experimental variant of the standard worker MPM
  • mpm_netware Multi-Processing Module implementing an exclusively threaded web server optimized for Novell NetWare
  • mpmt_os2 Hybrid multi-process, multi-threaded MPM for OS/2
  • prefork Implements a non-threaded, pre-forking web server
  • mpm_winnt - This Multi-Processing Module is optimized for Windows NT.
  • worker - Multi-Processing Module implementing a hybrid multi-threaded multi-process web server

Now, to the difference between prefork and worker.

The prefork MPM

implements a non-threaded, pre-forking web server that handles requests in a manner similar to Apache 1.3. It is appropriate for sites that need to avoid threading for compatibility with non-thread-safe libraries. It is also the best MPM for isolating each request, so that a problem with a single request will not affect any other.

The worker MPM implements a hybrid multi-process multi-threaded server and gives better performance, hence it should be preferred unless one is using other modules that contain non-thread-safe libraries (see also this discussion or this on Serverfault).

Force div element to stay in same place, when page is scrolled

You can do this replacing position:absolute; by position:fixed;.

Function not defined javascript

I just went through the same problem. And found out once you have a syntax or any type of error in you javascript, the whole file don't get loaded so you cannot use any of the other functions at all.

Concatenate text files with Windows command line, dropping leading lines

Use the FOR command to echo a file line by line, and with the 'skip' option to miss a number of starting lines...

FOR /F "skip=1" %i in (file2.txt) do @echo %i

You could redirect the output of a batch file, containing something like...

FOR /F %%i in (file1.txt) do @echo %%i
FOR /F "skip=1" %%i in (file2.txt) do @echo %%i

Note the double % when a FOR variable is used within a batch file.

Getting started with OpenCV 2.4 and MinGW on Windows 7

The instructions in @bsdnoobz answer are indeed helpful, but didn't get OpenCV to work on my system.

Apparently I needed to compile the library myself in order to get it to work, and not count on the pre-built binaries (which caused my programs to crash, probably due to incompatibility with my system).

I did get it to work, and wrote a comprehensive guide for compiling and installing OpenCV, and configuring Netbeans to work with it.

For completeness, it is also provided below.


When I first started using OpenCV, I encountered two major difficulties:

  1. Getting my programs NOT to crash immediately.
  2. Making Netbeans play nice, and especially getting timehe debugger to work.

I read many tutorials and "how-to" articles, but none was really comprehensive and thorough. Eventually I succeeded in setting up the environment; and after a while of using this (great) library, I decided to write this small tutorial, which will hopefully help others.

The are three parts to this tutorial:

  1. Compiling and installing OpenCV.
  2. Configuring Netbeans.
  3. An example program.

The environment I use is: Windows 7, OpenCV 2.4.0, Netbeans 7 and MinGW 3.20 (with compiler gcc 4.6.2).

Assumptions: You already have MinGW and Netbeans installed on your system.

Compiling and installing OpenCV

When downloading OpenCV, the archive actually already contains pre-built binaries (compiled libraries and DLL's) in the 'build' folder. At first, I tried using those binaries, assuming somebody had already done the job of compiling for me. That didn't work.

Eventually I figured I have to compile the entire library on my own system in order for it to work properly.

Luckily, the compilation process is rather easy, thanks to CMake. CMake (stands for Cross-platform Make) is a tool which generates makefiles specific to your compiler and platform. We will use CMake in order to configure our building and compilation settings, generate a 'makefile', and then compile the library.

The steps are:

  1. Download CMake and install it (in the installation wizard choose to add CMake to the system PATH).
  2. Download the 'release' version of OpenCV.
  3. Extract the archive to a directory of your choice. I will be using c:/opencv/.
  4. Launch CMake GUI.
    1. Browse for the source directory c:/opencv/.
    2. Choose where to build the binaries. I chose c:/opencv/release.
      CMake Configuration - 1
    3. Click 'Configure'. In the screen that opens choose the generator according to your compiler. In our case it's 'MinGW Makefiles'.
      CMake Configuration - 2
    4. Wait for everything to load, afterwards you will see this screen:
      CMake Configuration - 3
    5. Change the settings if you want, or leave the defaults. When you're done, press 'Configure' again. You should see 'Configuration done' at the log window, and the red background should disappear from all the cells.
      CMake Configuration - 4
    6. At this point CMake is ready to generate the makefile with which we will compile OpenCV with our compiler. Click 'Generate' and wait for the makefile to be generated. When the process is finished you should see 'Generating done'. From this point we will no longer need CMake.
  5. Open MinGW shell (The following steps can also be done from Windows' command prompt).
    1. Enter the directory c:/opencv/release/.
    2. Type mingw32-make and press enter. This should start the compilation process.
      MinGW Make
      MinGW Make - Compilation
    3. When the compilation is done OpenCV's binaries are ready to be used.
    4. For convenience, we should add the directory C:/opencv/release/bin to the system PATH. This will make sure our programs can find the needed DLL's to run.

Configuring Netbeans

Netbeans should be told where to find the header files and the compiled libraries (which were created in the previous section).

The header files are needed for two reasons: for compilation and for code completion. The compiled libraries are needed for the linking stage.

Note: In order for debugging to work, the OpenCV DLL's should be available, which is why we added the directory which contains them to the system PATH (previous section, step 5.4).

First, you should verify that Netbeans is configured correctly to work with MinGW. Please see the screenshot below and verify your settings are correct (considering paths changes according to your own installation). Also note that the make command should be from msys and not from Cygwin.

Netbeans MinGW Configuration

Next, for each new project you create in Netbeans, you should define the include path (the directory which contains the header files), the libraries path and the specific libraries you intend to use. Right-click the project name in the 'projects' pane, and choose 'properties'. Add the include path (modify the path according to your own installation):

Netbeans Project Include Path

Add the libraries path:

Netbeans Libraries Path

Add the specific libraries you intend to use. These libraries will be dynamically linked to your program in the linking stage. Usually you will need the core library plus any other libraries according to the specific needs of your program.

Netbeans Include Libraries

That's it, you are now ready to use OpenCV!

Summary

Here are the general steps you need to complete in order to install OpenCV and use it with Netbeans:

  1. Compile OpenCV with your compiler.
  2. Add the directory which contains the DLL's to your system PATH (in our case: c:/opencv/release/bin).
  3. Add the directory which contains the header files to your project's include path (in our case: c:/opencv/build/include).
  4. Add the directory which contains the compiled libraries to you project's libraries path (in our case: c:/opencv/release/lib).
  5. Add the specific libraries you need to be linked with your project (for example: libopencv_core240.dll.a).

Example - "Hello World" with OpenCV

Here is a small example program which draws the text "Hello World : )" on a GUI window. You can use it to check that your installation works correctly. After compiling and running the program, you should see the following window:

OpenCV Hello World

#include "opencv2/opencv.hpp"
#include "opencv2/highgui/highgui.hpp"

using namespace cv;

int main(int argc, char** argv) {
    //create a gui window:
    namedWindow("Output",1);

    //initialize a 120X350 matrix of black pixels:
    Mat output = Mat::zeros( 120, 350, CV_8UC3 );

    //write text on the matrix:
    putText(output,
            "Hello World :)",
            cvPoint(15,70),
            FONT_HERSHEY_PLAIN,
            3,
            cvScalar(0,255,0),
            4);

    //display the image:
    imshow("Output", output);

    //wait for the user to press any key:
    waitKey(0);

    return 0;
}

How to SELECT based on value of another SELECT

If you want to SELECT based on the value of another SELECT, then you probably want a "subselect":

http://beginner-sql-tutorial.com/sql-subquery.htm

For example, (from the link above):

  1. You want the first and last names from table "student_details" ...

  2. But you only want this information for those students in "science" class:

     SELECT id, first_name
     FROM student_details
     WHERE first_name IN (SELECT first_name
     FROM student_details
     WHERE subject= 'Science'); 
    

Frankly, I'm not sure this is what you're looking for or not ... but I hope it helps ... at least a little...

IMHO...

This view is not constrained

Right Click in then designing part on that component in which you got error and follow these steps:

  • [for ex. if error occur in Plain Text]

[1]

Plain Text Constraint Layout > Infer Constraints:

finally error has gone

How to capture multiple repeated groups?

Sorry, not Swift, just a proof of concept in the closest language at hand.

// JavaScript POC. Output:
// Matches:  ["GOODBYE","CRUEL","WORLD","IM","LEAVING","U","TODAY"]

let str = `GOODBYE,CRUEL,WORLD,IM,LEAVING,U,TODAY`
let matches = [];

function recurse(str, matches) {
    let regex = /^((,?([A-Z]+))+)$/gm
    let m
    while ((m = regex.exec(str)) !== null) {
        matches.unshift(m[3])
        return str.replace(m[2], '')
    }
    return "bzzt!"
}

while ((str = recurse(str, matches)) != "bzzt!") ;
console.log("Matches: ", JSON.stringify(matches))

Note: If you were really going to use this, you would use the position of the match as given by the regex match function, not a string replace.

How to open generated pdf using jspdf in new window

  1. Search in jspdf.js this:

    if(type == 'datauri') {
        document.location.href ='data:application/pdf;base64,' + Base64.encode(buffer);
    }
    
  2. Add :

    if(type == 'datauriNew') {   
        window.open('data:application/pdf;base64,' + Base64.encode(buffer));
    }
    
  3. call this option 'datauriNew' Saludos ;)

write a shell script to ssh to a remote machine and execute commands

There is are multiple ways to execute the commands or script in the multiple remote Linux machines. One simple & easiest way is via pssh (parallel ssh program)

pssh: is a program for executing ssh in parallel on a number of hosts. It provides features such as sending input to all of the processes, passing a password to ssh, saving the output to files, and timing out.

Example & Usage:

Connect to host1 and host2, and print "hello, world" from each:

 pssh -i -H "host1 host2" echo "hello, world"

Run commands via a script on multiple servers:

pssh -h hosts.txt -P -I<./commands.sh

Usage & run a command without checking or saving host keys:

pssh -h hostname_ip.txt -x '-q -o StrictHostKeyChecking=no -o PreferredAuthentications=publickey -o PubkeyAuthentication=yes' -i  'uptime; hostname -f'

If the file hosts.txt has a large number of entries, say 100, then the parallelism option may also be set to 100 to ensure that the commands are run concurrently:

pssh -i -h hosts.txt -p 100 -t 0 sleep 10000

Options:
-I: Read input and sends to each ssh process.
-P: Tells pssh to display output as it arrives.
-h: Reads the host's file.
-H : [user@]host[:port] for single-host.
-i: Display standard output and standard error as each host completes
-x args: Passes extra SSH command-line arguments
-o option: Can be used to give options in the format used in the configuration file.(/etc/ssh/ssh_config) (~/.ssh/config)
-p parallelism: Use the given number as the maximum number of concurrent connections
-q Quiet mode: Causes most warning and diagnostic messages to be suppressed.
-t: Make connections time out after the given number of seconds. 0 means pssh will not timeout any connections

When ssh'ing to the remote machine, how to handle when it prompts for RSA fingerprint authentication.

Disable the StrictHostKeyChecking to handle the RSA authentication prompt.
-o StrictHostKeyChecking=no

Source: man pssh

Free tool to Create/Edit PNG Images?

Paint.NET will create and edit PNGs with gusto. It's an excellent program in many respects. It's free as in beer and speech.

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

The following adds elements to a list in a loop.

l<-c()
i=1

while(i<100) {

    b<-i
    l<-c(l,b)
    i=i+1
}

Is there a foreach loop in Go?

I have jus implement this library:https://github.com/jose78/go-collection. This is an example about how to use the Foreach loop:

package main

import (
    "fmt"

    col "github.com/jose78/go-collection/collections"
)

type user struct {
    name string
    age  int
    id   int
}

func main() {
    newList := col.ListType{user{"Alvaro", 6, 1}, user{"Sofia", 3, 2}}
    newList = append(newList, user{"Mon", 0, 3})

    newList.Foreach(simpleLoop)
    
    if err := newList.Foreach(simpleLoopWithError); err != nil{
        fmt.Printf("This error >>> %v <<< was produced", err )  
    }
}

var simpleLoop col.FnForeachList = func(mapper interface{}, index int) {
    fmt.Printf("%d.- item:%v\n", index, mapper)
}


var simpleLoopWithError col.FnForeachList = func(mapper interface{}, index int) {
    if index > 1{
        panic(fmt.Sprintf("Error produced with index == %d\n", index))
    }
    fmt.Printf("%d.- item:%v\n", index, mapper)
}

The result of this execution should be:

0.- item:{Alvaro 6 1}
1.- item:{Sofia 3 2}
2.- item:{Mon 0 3}
0.- item:{Alvaro 6 1}
1.- item:{Sofia 3 2}
Recovered in f Error produced with index == 2

ERROR: Error produced with index == 2
This error >>> Error produced with index == 2
 <<< was produced

Try this code in playGrounD

Browse for a directory in C#

Note: there is no guarantee this code will work in future versions of the .Net framework. Using private .Net framework internals as done here through reflection is probably not good overall. Use the interop solution mentioned at the bottom, as the Windows API is less likely to change.

If you are looking for a Folder picker that looks more like the Windows 7 dialog, with the ability to copy and paste from a textbox at the bottom and the navigation pane on the left with favorites and common locations, then you can get access to that in a very lightweight way.

The FolderBrowserDialog UI is very minimal:

enter image description here

But you can have this instead:

enter image description here

Here's a class that opens a Vista-style folder picker using the .Net private IFileDialog interface, without directly using interop in the code (.Net takes care of that for you). It falls back to the pre-Vista dialog if not in a high enough Windows version. Should work in Windows 7, 8, 9, 10 and higher (theoretically).

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

namespace MyCoolCompany.Shuriken {
    /// <summary>
    /// Present the Windows Vista-style open file dialog to select a folder. Fall back for older Windows Versions
    /// </summary>
    public class FolderSelectDialog {
        private string _initialDirectory;
        private string _title;
        private string _fileName = "";

        public string InitialDirectory {
            get { return string.IsNullOrEmpty(_initialDirectory) ? Environment.CurrentDirectory : _initialDirectory; }
            set { _initialDirectory = value; }
        }
        public string Title {
            get { return _title ?? "Select a folder"; }
            set { _title = value; }
        }
        public string FileName { get { return _fileName; } }

        public bool Show() { return Show(IntPtr.Zero); }

        /// <param name="hWndOwner">Handle of the control or window to be the parent of the file dialog</param>
        /// <returns>true if the user clicks OK</returns>
        public bool Show(IntPtr hWndOwner) {
            var result = Environment.OSVersion.Version.Major >= 6
                ? VistaDialog.Show(hWndOwner, InitialDirectory, Title)
                : ShowXpDialog(hWndOwner, InitialDirectory, Title);
            _fileName = result.FileName;
            return result.Result;
        }

        private struct ShowDialogResult {
            public bool Result { get; set; }
            public string FileName { get; set; }
        }

        private static ShowDialogResult ShowXpDialog(IntPtr ownerHandle, string initialDirectory, string title) {
            var folderBrowserDialog = new FolderBrowserDialog {
                Description = title,
                SelectedPath = initialDirectory,
                ShowNewFolderButton = false
            };
            var dialogResult = new ShowDialogResult();
            if (folderBrowserDialog.ShowDialog(new WindowWrapper(ownerHandle)) == DialogResult.OK) {
                dialogResult.Result = true;
                dialogResult.FileName = folderBrowserDialog.SelectedPath;
            }
            return dialogResult;
        }

        private static class VistaDialog {
            private const string c_foldersFilter = "Folders|\n";

            private const BindingFlags c_flags = BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic;
            private readonly static Assembly s_windowsFormsAssembly = typeof(FileDialog).Assembly;
            private readonly static Type s_iFileDialogType = s_windowsFormsAssembly.GetType("System.Windows.Forms.FileDialogNative+IFileDialog");
            private readonly static MethodInfo s_createVistaDialogMethodInfo = typeof(OpenFileDialog).GetMethod("CreateVistaDialog", c_flags);
            private readonly static MethodInfo s_onBeforeVistaDialogMethodInfo = typeof(OpenFileDialog).GetMethod("OnBeforeVistaDialog", c_flags);
            private readonly static MethodInfo s_getOptionsMethodInfo = typeof(FileDialog).GetMethod("GetOptions", c_flags);
            private readonly static MethodInfo s_setOptionsMethodInfo = s_iFileDialogType.GetMethod("SetOptions", c_flags);
            private readonly static uint s_fosPickFoldersBitFlag = (uint) s_windowsFormsAssembly
                .GetType("System.Windows.Forms.FileDialogNative+FOS")
                .GetField("FOS_PICKFOLDERS")
                .GetValue(null);
            private readonly static ConstructorInfo s_vistaDialogEventsConstructorInfo = s_windowsFormsAssembly
                .GetType("System.Windows.Forms.FileDialog+VistaDialogEvents")
                .GetConstructor(c_flags, null, new[] { typeof(FileDialog) }, null);
            private readonly static MethodInfo s_adviseMethodInfo = s_iFileDialogType.GetMethod("Advise");
            private readonly static MethodInfo s_unAdviseMethodInfo = s_iFileDialogType.GetMethod("Unadvise");
            private readonly static MethodInfo s_showMethodInfo = s_iFileDialogType.GetMethod("Show");

            public static ShowDialogResult Show(IntPtr ownerHandle, string initialDirectory, string title) {
                var openFileDialog = new OpenFileDialog {
                    AddExtension = false,
                    CheckFileExists = false,
                    DereferenceLinks = true,
                    Filter = c_foldersFilter,
                    InitialDirectory = initialDirectory,
                    Multiselect = false,
                    Title = title
                };

                var iFileDialog = s_createVistaDialogMethodInfo.Invoke(openFileDialog, new object[] { });
                s_onBeforeVistaDialogMethodInfo.Invoke(openFileDialog, new[] { iFileDialog });
                s_setOptionsMethodInfo.Invoke(iFileDialog, new object[] { (uint) s_getOptionsMethodInfo.Invoke(openFileDialog, new object[] { }) | s_fosPickFoldersBitFlag });
                var adviseParametersWithOutputConnectionToken = new[] { s_vistaDialogEventsConstructorInfo.Invoke(new object[] { openFileDialog }), 0U };
                s_adviseMethodInfo.Invoke(iFileDialog, adviseParametersWithOutputConnectionToken);

                try {
                    int retVal = (int) s_showMethodInfo.Invoke(iFileDialog, new object[] { ownerHandle });
                    return new ShowDialogResult {
                        Result = retVal == 0,
                        FileName = openFileDialog.FileName
                    };
                }
                finally {
                    s_unAdviseMethodInfo.Invoke(iFileDialog, new[] { adviseParametersWithOutputConnectionToken[1] });
                }
            }
        }

        // Wrap an IWin32Window around an IntPtr
        private class WindowWrapper : IWin32Window {
            private readonly IntPtr _handle;
            public WindowWrapper(IntPtr handle) { _handle = handle; }
            public IntPtr Handle { get { return _handle; } }
        }
    }
}

I developed this as a cleaned up version of .NET Win 7-style folder select dialog by Bill Seddon of lyquidity.com (I have no affiliation). I wrote my own because his solution requires an additional Reflection class that isn't needed for this focused purpose, uses exception-based flow control, doesn't cache the results of its reflection calls. Note that the nested static VistaDialog class is so that its static reflection variables don't try to get populated if the Show method is never called.

It is used like so in a Windows Form:

var dialog = new FolderSelectDialog {
    InitialDirectory = musicFolderTextBox.Text,
    Title = "Select a folder to import music from"
};
if (dialog.Show(Handle)) {
    musicFolderTextBox.Text = dialog.FileName;
}

You can of course play around with its options and what properties it exposes. For example, it allows multiselect in the Vista-style dialog.

Also, please note that Simon Mourier gave an answer that shows how to do the exact same job using interop against the Windows API directly, though his version would have to be supplemented to use the older style dialog if in an older version of Windows. Unfortunately, I hadn't found his post yet when I worked up my solution. Name your poison!

CodeIgniter: "Unable to load the requested class"

In Windows, capitalization in paths doesn't matter. In Linux it does.

When you autoload, use "Foo" not "foo".

I believe that will do the trick.

I think it works when you take it out of autoloading because codeigniter is smart enough to figure out the capitalization in the path and classes are case independent in php.

call javascript function on hyperlink click

Ideally I would avoid generating links in you code behind altogether as your code will need recompiling every time you want to make a change to the 'markup' of each of those links. If you have to do it I would not embed your javascript 'calls' inside your HTML, it's a bad practice altogether, your markup should describe your document not what it does, thats the job of your javascript.

Use an approach where you have a specific id for each element (or class if its common functionality) and then use Progressive Enhancement to add the event handler(s), something like:

[c# example only probably not the way you're writing out your js]
Response.Write("<a href=\"/link/for/javascriptDisabled/Browsers.aspx\" id=\"uxAncMyLink\">My Link</a>");

[Javascript]  
document.getElementById('uxAncMyLink').onclick = function(e){

// do some stuff here

    return false;
    }

That way your code won't break for users with JS disabled and it will have a clear seperation of concerns.

Hope that is of use.

In Python, how do you convert a `datetime` object to seconds?

To get the Unix time (seconds since January 1, 1970):

>>> import datetime, time
>>> t = datetime.datetime(2011, 10, 21, 0, 0)
>>> time.mktime(t.timetuple())
1319148000.0

How many socket connections can a web server handle?

It looks like the answer is at least 12 million if you have a beefy server, your server software is optimized for it, you have enough clients. If you test from one client to one server, the number of port numbers on the client will be one of the obvious resource limits (Each TCP connection is defined by the unique combination of IP and port number at the source and destination).

(You need to run multiple clients as otherwise you hit the 64K limit on port numbers first)

When it comes down to it, this is a classic example of the witticism that "the difference between theory and practise is much larger in practise than in theory" - in practise achieving the higher numbers seems to be a cycle of a. propose specific configuration/architecture/code changes, b. test it till you hit a limit, c. Have I finished? If not then d. work out what was the limiting factor, e. go back to step a (rinse and repeat).

Here is an example with 2 million TCP connections onto a beefy box (128GB RAM and 40 cores) running Phoenix http://www.phoenixframework.org/blog/the-road-to-2-million-websocket-connections - they ended up needing 50 or so reasonably significant servers just to provide the client load (their initial smaller clients maxed out to early, eg "maxed our 4core/15gb box @ 450k clients").

Here is another reference for go this time at 10 million: http://goroutines.com/10m.

This appears to be java based and 12 million connections: https://mrotaru.wordpress.com/2013/06/20/12-million-concurrent-connections-with-migratorydata-websocket-server/

Reasons for using the set.seed function

basically set.seed() function will help to reuse the same set of random variables , which we may need in future to again evaluate particular task again with same random varibales

we just need to declare it before using any random numbers generating function.

Can't use WAMP , port 80 is used by IIS 7.5

This could also be an issue of port 80 being used by "Web Deployment Agent Service". you can stop it from administrative tools->services and free up that port. as shown here

Finding the type of an object in C++

As others indicated you can use dynamic_cast. But generally using dynamic_cast for finding out the type of the derived class you are working upon indicates the bad design. If you are overriding a function that takes pointer of A as the parameter then it should be able to work with the methods/data of class A itself and should not depend on the the data of class B. In your case instead of overriding if you are sure that the method you are writing will work with only class B, then you should write a new method in class B.

Using Java to pull data from a webpage?

The simplest solution (without depending on any third-party library or platform) is to create a URL instance pointing to the web page / link you want to download, and read the content using streams.

For example:

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.URL;
import java.net.URLConnection;


public class DownloadPage {

    public static void main(String[] args) throws IOException {

        // Make a URL to the web page
        URL url = new URL("http://stackoverflow.com/questions/6159118/using-java-to-pull-data-from-a-webpage");

        // Get the input stream through URL Connection
        URLConnection con = url.openConnection();
        InputStream is =con.getInputStream();

        // Once you have the Input Stream, it's just plain old Java IO stuff.

        // For this case, since you are interested in getting plain-text web page
        // I'll use a reader and output the text content to System.out.

        // For binary content, it's better to directly read the bytes from stream and write
        // to the target file.


        BufferedReader br = new BufferedReader(new InputStreamReader(is));

        String line = null;

        // read each line and write to System.out
        while ((line = br.readLine()) != null) {
            System.out.println(line);
        }
    }
}

Hope this helps.

How do I get the RootViewController from a pushed controller?

I encounter a strange condition.

self.viewControllers.first is not root viewController always.

Generally, self.viewControllers.first is root viewController indeed. But sometimes it's not.

class MyCustomMainNavigationController: UINavigationController {

    function configureForView(_ v: UIViewController, animated: Bool) {
        let root = self.viewControllers.first
        let isRoot = (v == root)
    
        // Update UI based on isRoot
        // ....
    }
}

extension MyCustomMainNavigationController: UINavigationControllerDelegate {
    func navigationController(_ navigationController: UINavigationController, 
        willShow viewController: UIViewController, 
        animated: Bool) {

        self.configureForView(viewController, animated: animated)
    }
}

My issue:

Generally, self.viewControllers.first is root viewController. But, when I call popToRootViewController(animated:), and then it triggers navigationController(_:willShow:animated:). At this moment, self.viewControllers.first is NOT root viewController, it's the last viewController which will disappear.

Summary

  • self.viewControllers.first is not always root viewController. Sometime, it will be the last viewController.

So, I suggest to keep rootViewController by property when self.viewControllers have ONLY one viewController. I get root viewController in viewDidLoad() of custom UINavigationController.

class MyCustomMainNavigationController: UINavigationController {
    fileprivate var myRoot: UIViewController!
    override func viewDidLoad() {

        super.viewDidLoad()

        // My UINavigationController is defined in storyboard. 
        // So at this moment, 
        // I can get root viewController by `self.topViewController!`
        let v = self.topViewController!
        self.myRoot = v
    }

}

Enviroments:

  • iPhone 7 with iOS 14.0.1
  • Xcode 12.0.1 (12A7300)

View tabular file such as CSV from command line

tblless in the Tabulator package wraps the unix column command, and also aligns numeric columns.

Retrieve filename from file descriptor in C

You can use fstat() to get the file's inode by struct stat. Then, using readdir() you can compare the inode you found with those that exist (struct dirent) in a directory (assuming that you know the directory, otherwise you'll have to search the whole filesystem) and find the corresponding file name. Nasty?

SELECT INTO Variable in MySQL DECLARE causes syntax error?

It is worth noting that despite the fact that you can SELECT INTO global variables like:

SELECT ... INTO @XYZ ...

You can NOT use FETCH INTO global variables like:

FETCH ... INTO @XYZ

Looks like it's not a bug. I hope it will be helpful to someone...

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

Instead of using HTML entities like &nbsp; and &emsp; (as others have suggested), you can use the Unicode em space (8195 in UTF-8) directly. Try copy-pasting the following into your README.md. The spaces at the start of the lines are em spaces.

The action of every agent <br />
  into the world <br />
starts <br />
  from their physical selves. <br />

svn over HTTP proxy

Ok, this should be really easy:

$ sudo vi /etc/subversion/servers

Edit the file:

[Global]
http-proxy-host=my.proxy.com
http-proxy-port=3128

Save it, run svn again and it will work.

Single Result from Database by using mySQLi

Use mysqli_fetch_row(). Try this,

$query = "SELECT ssfullname, ssemail FROM userss WHERE user_id = ".$user_id;
$result = mysqli_query($conn, $query);
$row   = mysqli_fetch_row($result);

$ssfullname = $row['ssfullname'];
$ssemail    = $row['ssemail'];

Adding local .aar files to Gradle build using "flatDirs" is not working

You can do it this way. It needs to go in the maven format:

repositories {
  maven { url uri('folderName')}
}

And then your AAR needs to go in a folder structure for a group id "com.example":

folderName/
  com/
    example/
       verion/
          myaar-version.aar

Then reference as a dependency:

compile 'com.example:myaar:version@aar'

Where version is the version of your aar file (ie, 3.0, etc)

Regular expression search replace in Sublime Text 2

Important: Use the ( ) parentheses in your search string

While the previous answer is correct there is an important thing to emphasize! All the matched segments in your search string that you want to use in your replacement string must be enclosed by ( ) parentheses, otherwise these matched segments won't be accessible to defined variables such as $1, $2 or \1, \2 etc.

For example we want to replace 'em' with 'px' but preserve the digit values:

    margin: 10em;  /* Expected: margin: 10px */
    margin: 2em;   /* Expected: margin: 2px */
  • Replacement string: margin: $1px or margin: \1px
  • Search string (CORRECT): margin: ([0-9]*)em // with parentheses
  • Search string (INCORRECT): margin: [0-9]*em

CORRECT CASE EXAMPLE: Using margin: ([0-9]*)em search string (with parentheses). Enclose the desired matched segment (e.g. $1 or \1) by ( ) parentheses as following:

  • Find: margin: ([0-9]*)em (with parentheses)
  • Replace to: margin: $1px or margin: \1px
  • Result:
    margin: 10px;
    margin: 2px;

INCORRECT CASE EXAMPLE: Using margin: [0-9]*em search string (without parentheses). The following regex pattern will match the desired lines but matched segments will not be available in replaced string as variables such as $1 or \1:

  • Find: margin: [0-9]*em (without parentheses)
  • Replace to: margin: $1px or margin: \1px
  • Result:
    margin: px; /* `$1` is undefined */
    margin: px; /* `$1` is undefined */

SQLSTATE[28000] [1045] Access denied for user 'root'@'localhost' (using password: YES) Symfony2

You need to set the password for root@localhost to be blank. There are two ways:

  • The MySQL SET PASSWORD command:

    SET PASSWORD FOR root@localhost=PASSWORD('');
    
  • Using the command-line mysqladmin tool:

    mysqladmin -u root -pCURRENTPASSWORD password ''
    

Best way to replace multiple characters in a string?

>>> a = '&#'
>>> print a.replace('&', r'\&')
\&#
>>> print a.replace('#', r'\#')
&\#
>>> 

You want to use a 'raw' string (denoted by the 'r' prefixing the replacement string), since raw strings to not treat the backslash specially.

Error in plot.window(...) : need finite 'xlim' values

I had the same problem. My solution was to make all vectors numeric.

Oracle SQL - DATE greater than statement

you have to use the To_Date() function to convert the string to date ! http://www.techonthenet.com/oracle/functions/to_date.php

Find all files in a folder

You can try with Directory.GetFiles and fix your pattern

 string[] files = Directory.GetFiles(@"c:\", "*.txt");

 foreach (string file in files)
 {
    File.Copy(file, "....");
 }

 Or Move

 foreach (string file in files)
 {
    File.Move(file, "....");
 }     

http://msdn.microsoft.com/en-us/library/wz42302f

Setting onClickListener for the Drawable right of an EditText

You don't have access to the right image as far my knowledge, unless you override the onTouch event. I suggest to use a RelativeLayout, with one editText and one imageView, and set OnClickListener over the image view as below:

<RelativeLayout
        android:id="@+id/rlSearch"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:background="@android:drawable/edit_text"
        android:padding="5dip" >

        <EditText
            android:id="@+id/txtSearch"
            android:layout_width="match_parent"

            android:layout_height="wrap_content"
            android:layout_centerVertical="true"
            android:layout_toLeftOf="@+id/imgSearch"
            android:background="#00000000"
            android:ems="10"/>

        <ImageView
            android:id="@+id/imgSearch"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignParentRight="true"
            android:layout_centerVertical="true"
            android:src="@drawable/btnsearch" />
    </RelativeLayout>

How to check which PHP extensions have been enabled/disabled in Ubuntu Linux 12.04 LTS?

Checking for installed php modules and packages

In addition to running

php -m

to get the list of installed php modules, you will probably find it helpful to get the list of the currently installed php packages in Ubuntu:

sudo dpkg --get-selections | grep -v deinstall | grep php

This is helpful since Ubuntu makes php modules available via packages.

You can then install the needed modules by selecting from the available Ubuntu php packages, which you can view by running:

sudo apt-cache search php | grep "^php5-"

Or, for Ubuntu 16.04 and higher:

sudo apt-cache search php | grep "^php7"

As you have mentioned, there is plenty of information available on the actual installation of the packages that you might require, so I won't go into detail about that here.

Related: Enabling / disabling installed php modules

It is possible that an installed module has been disabled. In that case, it won't show up when running php -m, but it will show up in the list of installed Ubuntu packages.

Modules can be enabled/disabled via the php5enmod tool (phpenmod on later distros) which is part of the php-common package.

Ubuntu 12.04:

Enabled modules are symlinked in /etc/php5/conf.d

Ubuntu 12.04: (with PHP 5.4+)

To enable an installed module:

php5enmod <modulename>

To disable an installed module:

php5dismod <modulename>

Ubuntu 16.04 (php7) and higher:

To enable an installed module:

phpenmod <modulename>

To disable an installed module:

phpdismod <modulename>

Reload Apache

Remember to reload Apache2 after enabling/disabling:

service apache2 reload

Shorthand if/else statement Javascript

var x = y !== undefined ? y : 1;

Note that var x = y || 1; would assign 1 for any case where y is falsy (e.g. false, 0, ""), which may be why it "didn't work" for you. Also, if y is a global variable, if it's truly not defined you may run into an error unless you access it as window.y.


As vol7ron suggests in the comments, you can also use typeof to avoid the need to refer to global vars as window.<name>:

var x = typeof y != "undefined" ? y : 1;

What is initial scale, user-scalable, minimum-scale, maximum-scale attribute in meta tag?

viewport meta tag on mobile browser,

The initial-scale property controls the zoom level when the page is first loaded. The maximum-scale, minimum-scale, and user-scalable properties control how users are allowed to zoom the page in or out.

@Resource vs @Autowired

The primary difference is, @Autowired is a spring annotation. Whereas @Resource is specified by the JSR-250, as you pointed out yourself. So the latter is part of Java whereas the former is Spring specific.

Hence, you are right in suggesting that, in a sense. I found folks use @Autowired with @Qualifier because it is more powerful. Moving from some framework to some other is considered very unlikely, if not myth, especially in the case of Spring.

Leave out quotes when copying from cell

Possible problem in relation to answer from "user3616725":
Im on Windows 8.1 and there seems to be a problem with the linked VBA code from accepted answer from "user3616725":

Sub CopyCellContents()
 ' !!! IMPORTANT !!!:
 ' CREATE A REFERENCE IN THE VBE TO "Microsft Forms 2.0 Library" OR "Microsft Forms 2.0 Object Library"
 ' DO THIS BY (IN VBA EDITOR) CLICKING TOOLS -> REFERENCES & THEN TICKING "Microsoft Forms 2.0 Library" OR "Microsft Forms 2.0 Object Library"
 Dim objData As New DataObject
 Dim strTemp As String
 strTemp = ActiveCell.Value
 objData.SetText (strTemp)
 objData.PutInClipboard
End Sub

Details:
Running above code and pasting clipboard into a cell in Excel I get two symbols composed of squares with a question mark inside, like this: ??. Pasting into Notepad doesn't even show anything.

Solution:
After searching for quite some time I found another VBA script from user "Nepumuk" which makes use of the Windows API. Here's his code that finally worked for me:

Option Explicit

Private Declare Function OpenClipboard Lib "user32.dll" ( _
    ByVal hwnd As Long) As Long
Private Declare Function CloseClipboard Lib "user32.dll" () As Long
Private Declare Function EmptyClipboard Lib "user32.dll" () As Long
Private Declare Function SetClipboardData Lib "user32.dll" ( _
    ByVal wFormat As Long, _
    ByVal hMem As Long) As Long
Private Declare Function GlobalAlloc Lib "kernel32.dll" ( _
    ByVal wFlags As Long, _
    ByVal dwBytes As Long) As Long
Private Declare Function GlobalLock Lib "kernel32.dll" ( _
    ByVal hMem As Long) As Long
Private Declare Function GlobalUnlock Lib "kernel32.dll" ( _
    ByVal hMem As Long) As Long
Private Declare Function GlobalFree Lib "kernel32.dll" ( _
    ByVal hMem As Long) As Long
Private Declare Function lstrcpy Lib "kernel32.dll" ( _
    ByVal lpStr1 As Any, _
    ByVal lpStr2 As Any) As Long

Private Const CF_TEXT As Long = 1&

Private Const GMEM_MOVEABLE As Long = 2

Public Sub Beispiel()
    Call StringToClipboard("Hallo ...")
End Sub

Private Sub StringToClipboard(strText As String)
    Dim lngIdentifier As Long, lngPointer As Long
    lngIdentifier = GlobalAlloc(GMEM_MOVEABLE, Len(strText) + 1)
    lngPointer = GlobalLock(lngIdentifier)
    Call lstrcpy(ByVal lngPointer, strText)
    Call GlobalUnlock(lngIdentifier)
    Call OpenClipboard(0&)
    Call EmptyClipboard
    Call SetClipboardData(CF_TEXT, lngIdentifier)
    Call CloseClipboard
    Call GlobalFree(lngIdentifier)
End Sub

To use it the same way like the first VBA code from above, change the Sub "Beispiel()" from:

Public Sub Beispiel()
    Call StringToClipboard("Hallo ...")
End Sub

To:

Sub CopyCellContents()
    Call StringToClipboard(ActiveCell.Value)
End Sub

And run it via Excel macro menu like suggested from "user3616725" from accepted answer:

Back in Excel, go Tools>Macro>Macros and select the macro called "CopyCellContents" and then choose Options from the dialog. Here you can assign the macro to a shortcut key (eg like Ctrl+c for normal copy) - I used Ctrl+q.

Then, when you want to copy a single cell over to Notepad/wherever, just do Ctrl+q (or whatever you chose) and then do a Ctrl+v or Edit>Paste in your chosen destination.


Edit (21st of November in 2015):
@ comment from "dotctor":
No, this seriously is no new question! In my opinion it is a good addition for the accepted answer as my answer addresses problems that you can face when using the code from the accepted answer. If I would have more reputation, I would have created a comment.
@ comment from "Teepeemm":
Yes, you are right, answers beginning with title "Problem:" are misleading. Changed to: "Possible problem in relation to answer from "user3616725":". As a comment I certainly would have written much more compact.

Get user input from textarea

<pre>
  <input type="text"  #titleInput>
  <button type="submit" (click) = 'addTodo(titleInput.value)'>Add</button>
</pre>

{
  addTodo(title:string) {
    console.log(title);
  }
}    

GLYPHICONS - bootstrap icon font hex value

If you want to use glyph icons with bootstrap 2.3.2, Add the font files from bootstrap 3 to your project folder then copy this to your css file

 @font-face {
  font-family: 'Glyphicons Halflings';
  src: url('../fonts/glyphicons-halflings-regular.eot');
  src: url('../fonts/glyphicons-halflings-regular.eot?#iefix') format('embedded-opentype'), url('../fonts/glyphicons-halflings-regular.woff') format('woff'), url('../fonts/glyphicons-halflings-regular.ttf') format('truetype'), url('../fonts/glyphicons-halflings-regular.svg#glyphicons-halflingsregular') format('svg');
}

How to convert a string to a date in sybase

Several ways to accomplish that but be aware that your DB date_format option & date_order option settings could affect the incoming format:

Select 
   cast('2008-09-16' as date)
   convert(date,'16/09/2008',103)
   date('2008-09-16')
from dummy;

JSON parsing using Gson for Java

You can use a separate class to represent the JSON object and use @SerializedName annotations to specify the field name to grab for each data member:

public class Response {

   @SerializedName("data")
   private Data data;

   private static class Data {
      @SerializedName("translations")
      public Translation[] translations;
   }

   private static class Translation {
      @SerializedName("translatedText")
      public String translatedText;
   }

   public String getTranslatedText() {
      return data.translations[0].translatedText;
   }
}

Then you can do the parsing in your parse() method using a Gson object:

Gson gson = new Gson();
Response response = gson.fromJson(jsonLine, Response.class);

System.out.println("Translated text: " + response.getTranslatedText());

With this approach, you can reuse the Response class to add any other additional fields to pick up other data members you might want to extract from JSON -- in case you want to make changes to get results for, say, multiple translations in one call, or to get an additional string for the detected source language.

How do I remove my IntelliJ license in 2019.3?

Not sure about older versions, but in 2016.2 removing the .key file(s) didn't work for me.

I'm using my JetBrains account and used the 'Remove License' button found at the bottom of the registration dialog. You can find this under the Help menu or from the startup dialog via Configure -> Manage License....

Android ImageButton with a selected state?

ToggleImageButton which implements Checkable interface and supports OnCheckedChangeListener and android:checked xml attribute:

public class ToggleImageButton extends ImageButton implements Checkable {
    private OnCheckedChangeListener onCheckedChangeListener;

    public ToggleImageButton(Context context) {
        super(context);
    }

    public ToggleImageButton(Context context, AttributeSet attrs) {
        super(context, attrs);
        setChecked(attrs);
    }

    public ToggleImageButton(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
        setChecked(attrs);
    }

    private void setChecked(AttributeSet attrs) {
        TypedArray a = getContext().obtainStyledAttributes(attrs, R.styleable.ToggleImageButton);
        setChecked(a.getBoolean(R.styleable.ToggleImageButton_android_checked, false));
        a.recycle();
    }

    @Override
    public boolean isChecked() {
        return isSelected();
    }

    @Override
    public void setChecked(boolean checked) {
        setSelected(checked);

        if (onCheckedChangeListener != null) {
            onCheckedChangeListener.onCheckedChanged(this, checked);
        }
    }

    @Override
    public void toggle() {
        setChecked(!isChecked());
    }

    @Override
    public boolean performClick() {
        toggle();
        return super.performClick();
    }

    public OnCheckedChangeListener getOnCheckedChangeListener() {
        return onCheckedChangeListener;
    }

    public void setOnCheckedChangeListener(OnCheckedChangeListener onCheckedChangeListener) {
        this.onCheckedChangeListener = onCheckedChangeListener;
    }

    public static interface OnCheckedChangeListener {
        public void onCheckedChanged(ToggleImageButton buttonView, boolean isChecked);
    }
}

res/values/attrs.xml:

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <declare-styleable name="ToggleImageButton">
        <attr name="android:checked" />
    </declare-styleable>
</resources>

Reading file line by line (with space) in Unix Shell scripting - Issue

Try this,

IFS=''
while read line
do
    echo $line
done < file.txt

EDIT:

From man bash

IFS - The Internal Field Separator that is used for word
splitting after expansion and to split lines into words
with  the  read  builtin  command. The default value is
``<space><tab><newline>''

No assembly found containing an OwinStartupAttribute Error

Add the following key in Web.config will remove the code

<appSettings>

  <add key="owin:AutomaticAppStartup" value="false" /> 
</appSettings>

How to set label size in Bootstrap

You'll have to do 2 things to make a Bootstrap label (or anything really) adjust sizes based on screen size:

  • Use a media query per display size range to adjust the CSS.
  • Override CSS sizing set by Bootstrap. You do this by making your CSS rules more specific than Bootstrap's. By default, Bootstrap sets .label { font-size: 75% }. So any extra selector on your CSS rule will make it more specific.

Here's an example CSS listing to accomplish what you are asking, using the default 4 sizes in Bootstrap:

@media (max-width: 767) {
    /* your custom css class on a parent will increase specificity */
    /* so this rule will override Bootstrap's font size setting */
    .autosized .label { font-size: 14px; }
}

@media (min-width: 768px) and (max-width: 991px) {
    .autosized .label { font-size: 16px; }
}

@media (min-width: 992px) and (max-width: 1199px) {
    .autosized .label { font-size: 18px; }
}

@media (min-width: 1200px) {
    .autosized .label { font-size: 20px; }
}

Here is how it could be used in the HTML:

<!-- any ancestor could be set to autosized -->
<div class="autosized">
    ...
        ...
            <span class="label label-primary">Label 1</span>
</div>

Using PropertyInfo.GetValue()

In your example propertyInfo.GetValue(this, null) should work. Consider altering GetNamesAndTypesAndValues() as follows:

public void GetNamesAndTypesAndValues()
{
  foreach (PropertyInfo propertyInfo in allClassProperties)
  {
    Console.WriteLine("{0} [type = {1}] [value = {2}]",
      propertyInfo.Name,
      propertyInfo.PropertyType,
      propertyInfo.GetValue(this, null));
  }
}

Forward declaration of a typedef in C++

To "fwd declare a typedef" you need to fwd declare a class or a struct and then you can typedef declared type. Multiple identical typedefs are acceptable by compiler.

long form:

class MyClass;
typedef MyClass myclass_t;

short form:

typedef class MyClass myclass_t;

How to reset form body in bootstrap modal box?

Just set the empty values to the input fields when modal is hiding.

$('#Modal_Id').on('hidden', function () {
   $('#Form_Id').find('input[type="text"]').val('');
});

How do I push a new local branch to a remote Git repository and track it too?

To create a new branch by branching off from an existing branch

git checkout -b <new_branch>

and then push this new branch to repository using

git push -u origin <new_branch>

This creates and pushes all local commits to a newly created remote branch origin/<new_branch>

Why is pydot unable to find GraphViz's executables in Windows 8?

For windows 8.1 & python 2.7 , I fixed the problem by following below steps

1 . Download and install graphviz-2.38.msi https://graphviz.gitlab.io/_pages/Download/Download_windows.html

2 . Set the path variable

Control Panel > System and Security > System > Advanced System Settings > Environment Variables > Path > Edit add 'C:\Program Files (x86)\Graphviz2.38\bin'

  1. Restart your currently running application that requires the path

What is the difference between typeof and instanceof and when should one be used vs. the other?

instanceof in Javascript can be flaky - I believe major frameworks try to avoid its use. Different windows is one of the ways in which it can break - I believe class hierarchies can confuse it as well.

There are better ways for testing whether an object is a certain built-in type (which is usually what you want). Create utility functions and use them:

function isFunction(obj) {
  return typeof(obj) == "function";
}
function isArray(obj) {
  return typeof(obj) == "object" 
      && typeof(obj.length) == "number" 
      && isFunction(obj.push);
}

And so on.

How to install beautiful soup 4 with python 2.7 on windows

You don't need pip for installing Beautiful Soup - you can just download it and run python setup.py install from the directory that you have unzipped BeautifulSoup in (assuming that you have added Python to your system PATH - if you haven't and you don't want to you can run C:\Path\To\Python27\python "C:\Path\To\BeautifulSoup\setup.py" install)

However, you really should install pip - see How to install pip on Windows for how to do that best (via @MartijnPieters comment)

How to get the last char of a string in PHP?

From PHP 7.1 you can do this (Accepted rfc for negative string offsets):

<?php
$silly = 'Mary had a little lamb';
echo $silly[-20];
echo $silly{-6};
echo $silly[-3];
echo $silly[-15];
echo $silly[-13];
echo $silly[-1];
echo $silly[-4];
echo $silly{-10};
echo $silly[-4];
echo $silly[-8];
echo $silly{3}; // <-- this will be deprecated in PHP 7.4
die();

I'll let you guess the output.

Also, I added this to xenonite's performance code with these results:

substr() took 7.0334868431091seconds

array access took 2.3111131191254seconds

Direct string access (negative string offsets) took 1.7971360683441seconds

How can I pass arguments to anonymous functions in JavaScript?

The delegates:

function displayMessage(message, f)
{
    f(message); // execute function "f" with variable "message"
}

function alerter(message)
{
    alert(message);
}

function writer(message)
{
    document.write(message);
}

Running the displayMessage function:

function runDelegate()
{
    displayMessage("Hello World!", alerter); // alert message

    displayMessage("Hello World!", writer); // write message to DOM
}

How can I insert a line break into a <Text> component in React Native?

This worked for me

<Text>{`Hi~\nthis is a test message.`}</Text>

(react-native 0.41.0)

Posting JSON Data to ASP.NET MVC

The simplest way of doing this

I urge you to read this blog post that directly addresses your problem.

Using custom model binders isn't really wise as Phil Haack pointed out (his blog post is linked in the upper blog post as well).

Basically you have three options:

  1. Write a JsonValueProviderFactory and use a client side library like json2.js to communicate wit JSON directly.

  2. Write a JQueryValueProviderFactory that understands the jQuery JSON object transformation that happens in $.ajax or

  3. Use the very simple and quick jQuery plugin outlined in the blog post, that prepares any JSON object (even arrays that will be bound to IList<T> and dates that will correctly parse on the server side as DateTime instances) that will be understood by Asp.net MVC default model binder.

Of all three, the last one is the simplest and doesn't interfere with Asp.net MVC inner workings thus lowering possible bug surface. Using this technique outlined in the blog post will correctly data bind your strong type action parameters and validate them as well. So it is basically a win win situation.

How do I return a char array from a function?

As you're using C++ you could use std::string.

Validate form field only on submit or user input

Use $dirty flag to show the error only after user interacted with the input:

<div>
  <input type="email" name="email" ng-model="user.email" required />
  <span ng-show="form.email.$dirty && form.email.$error.required">Email is required</span>
</div>

If you want to trigger the errors only after the user has submitted the form than you may use a separate flag variable as in:

<form ng-submit="submit()" name="form" ng-controller="MyCtrl">
  <div>
    <input type="email" name="email" ng-model="user.email" required />
    <span ng-show="(form.email.$dirty || submitted) && form.email.$error.required">
      Email is required
    </span>
  </div>

  <div>
    <button type="submit">Submit</button>
  </div>
</form>
function MyCtrl($scope){
  $scope.submit = function(){
    // Set the 'submitted' flag to true
    $scope.submitted = true;
    // Send the form to server
    // $http.post ...
  } 
};

Then, if all that JS inside ng-showexpression looks too much for you, you can abstract it into a separate method:

function MyCtrl($scope){
  $scope.submit = function(){
    // Set the 'submitted' flag to true
    $scope.submitted = true;
    // Send the form to server
    // $http.post ...
  }

  $scope.hasError = function(field, validation){
    if(validation){
      return ($scope.form[field].$dirty && $scope.form[field].$error[validation]) || ($scope.submitted && $scope.form[field].$error[validation]);
    }
    return ($scope.form[field].$dirty && $scope.form[field].$invalid) || ($scope.submitted && $scope.form[field].$invalid);
  };

};
<form ng-submit="submit()" name="form">
  <div>
    <input type="email" name="email" ng-model="user.email" required />
    <span ng-show="hasError('email', 'required')">required</span>
  </div>

  <div>
    <button type="submit">Submit</button>
  </div>
</form>

Identifying and solving javax.el.PropertyNotFoundException: Target Unreachable

For 1. topic (Target Unreachable, identifier 'bean' resolved to null);

I checked valuable answers the @BalusC and the other sharers but I exceed the this problem like this on my scenario. After the creating a new xhtml with different name and creating bean class with different name then I wrote (not copy-paste) the codes step by step to the new bean class and new xhtml file.

How to run TestNG from command line

You will need to use semicolon as delimiter while specifying the jar and class file path in windows. This solved the issue.
Assuming the class file is under C:.

java -cp ".;C:\testng.jar" org.testng.TestNG testing.xml

How to map and remove nil values in Ruby

Definitely compact is the best approach for solving this task. However, we can achieve the same result just with a simple subtraction:

[1, nil, 3, nil, nil] - [nil]
 => [1, 3]

byte array to pdf

Usually this happens if something is wrong with the byte array.

File.WriteAllBytes("filename.PDF", Byte[]);

This creates a new file, writes the specified byte array to the file, and then closes the file. If the target file already exists, it is overwritten.

Asynchronous implementation of this is also available.

public static System.Threading.Tasks.Task WriteAllBytesAsync 
(string path, byte[] bytes, System.Threading.CancellationToken cancellationToken = null);

What is "with (nolock)" in SQL Server?

Use nolock when you are okay with the "dirty" data. Which means nolock can also read data which is in the process of being modified and/or uncommitted data.

It's generally not a good idea to use it in high transaction environment and that is why it is not a default option on query.

Print new output on same line

Lets take an example where you want to print numbers from 0 to n in the same line. You can do this with the help of following code.

n=int(raw_input())
i=0
while(i<n):
    print i,
    i = i+1

At input, n = 5

Output : 0 1 2 3 4 

How to use HTTP_X_FORWARDED_FOR properly?

You can also solve this problem via Apache configuration using mod_remoteip, by adding the following to a conf.d file:

RemoteIPHeader X-Forwarded-For
RemoteIPInternalProxy 172.16.0.0/12
LogFormat "%a %l %u %t \"%r\" %>s %b \"%{Referer}i\" \"%{User-Agent}i\"" combined

Best XML Parser for PHP

Have a look at PHP's available XML extensions.

The main difference between XML Parser and SimpleXML is that the latter is not a pull parser. SimpleXML is built on top of the DOM extensions and will load the entire XML file into memory. XML Parser like XMLReader will only load the current node into memory. You define handlers for specific nodes which will get triggered when the Parser encounters it. That is faster and saves on memory. You pay for that with not being able to use XPath.

Personally, I find SimpleXml quite limiting (hence simple) in what it offers over DOM. You can switch between DOM and SimpleXml easily though, but I usually dont bother and go the DOM route directly. DOM is an implementation of the W3C DOM API, so you might be familiar with it from other languages, for instance JavaScript.

How can I introduce multiple conditions in LIKE operator?

Here is an alternative way:

select * from tbl where col like 'ABC%'
union
select * from tbl where col like 'XYZ%'
union
select * from tbl where col like 'PQR%';

Here is the test code to verify:

create table tbl (col varchar(255));
insert into tbl (col) values ('ABCDEFG'), ('HIJKLMNO'), ('PQRSTUVW'), ('XYZ');
select * from tbl where col like 'ABC%'
union
select * from tbl where col like 'XYZ%'
union
select * from tbl where col like 'PQR%';
+----------+
| col      |
+----------+
| ABCDEFG  |
| XYZ      |
| PQRSTUVW |
+----------+
3 rows in set (0.00 sec)

Sort ArrayList of custom Objects by property

Well if you using Java 8 or older version Here is the Best solution.

Collections.sort(studentList, Comparator.comparing(Student::getCgpa).reversed().thenComparing(Student:: getFname).thenComparing(Student::getId));

In this case, it will first sort with 'getCgpa' first and for the second part it will sort with getFname and getId. Which is field into the pojo class.

What's the purpose of git-mv?

Maybe git mv has changed since these answers were posted, so I will update briefly. In my view, git mv is not accurately described as short hand for:

 # not accurate: #
 mv oldname newname
 git add newname
 git rm oldname

I use git mv frequently for two reasons that have not been described in previous answers:

  1. Moving large directory structures, where I have mixed content of both tracked and untracked files. Both tracked and untracked files will move, and retain their tracking/untracking status

  2. Moving files and directories that are large, I have always assumed that git mv will reduce the size of the repository DB history size. This is because moving/renaming a file is indexation/reference delta. I have not verified this assumption, but it seems logical.

How do I remove an object from an array with JavaScript?

var apps = [{id:34,name:'My App',another:'thing'},{id:37,name:'My New App',another:'things'}];

// get index of object with id:37

var removeIndex = apps.map(function(item) { return item.id; }).indexOf(37);

// remove object

apps.splice(removeIndex, 1);

how to call a method in another Activity from Activity

You should not create an instance of the activity class. It is wrong. Activity has ui and lifecycle and activity is started by startActivity(intent)

You can use startActivityForResult or you can pass the values from one activity to another using intents and do what is required. But it depends on what you intend to do in the method.

Offline Speech Recognition In Android (JellyBean)

A simple and flexible offline recognition on Android is implemented by CMUSphinx, an open source speech recognition toolkit. It works purely offline, fast and configurable It can listen continuously for keyword, for example.

You can find latest code and tutorial here.

Update in 2019: Time goes fast, CMUSphinx is not that accurate anymore. I recommend to try Kaldi toolkit instead. The demo is here.

Which is better, return value or out parameter?

You should generally prefer a return value over an out param. Out params are a necessary evil if you find yourself writing code that needs to do 2 things. A good example of this is the Try pattern (such as Int32.TryParse).

Let's consider what the caller of your two methods would have to do. For the first example I can write this...

int foo = GetValue();

Notice that I can declare a variable and assign it via your method in one line. FOr the 2nd example it looks like this...

int foo;
GetValue(out foo);

I'm now forced to declare my variable up front and write my code over two lines.

update

A good place to look when asking these types of question is the .NET Framework Design Guidelines. If you have the book version then you can see the annotations by Anders Hejlsberg and others on this subject (page 184-185) but the online version is here...

http://msdn.microsoft.com/en-us/library/ms182131(VS.80).aspx

If you find yourself needing to return two things from an API then wrapping them up in a struct/class would be better than an out param.

How to clone an InputStream?

UPD. Check the comment before. It isn't exactly what was asked.

If you are using apache.commons you may copy streams using IOUtils .

You can use following code:

InputStream = IOUtils.toBufferedInputStream(toCopy);

Here is the full example suitable for your situation:

public void cloneStream() throws IOException{
    InputStream toCopy=IOUtils.toInputStream("aaa");
    InputStream dest= null;
    dest=IOUtils.toBufferedInputStream(toCopy);
    toCopy.close();
    String result = new String(IOUtils.toByteArray(dest));
    System.out.println(result);
}

This code requires some dependencies:

MAVEN

<dependency>
    <groupId>commons-io</groupId>
    <artifactId>commons-io</artifactId>
    <version>2.4</version>
</dependency>

GRADLE

'commons-io:commons-io:2.4'

Here is the DOC reference for this method:

Fetches entire contents of an InputStream and represent same data as result InputStream. This method is useful where,

Source InputStream is slow. It has network resources associated, so we cannot keep it open for long time. It has network timeout associated.

You can find more about IOUtils here: http://commons.apache.org/proper/commons-io/javadocs/api-2.4/org/apache/commons/io/IOUtils.html#toBufferedInputStream(java.io.InputStream)

Android/Java - Date Difference in days

There's a simple solution, that at least for me, is the only feasible solution.

The problem is that all the answers I see being tossed around - using Joda, or Calendar, or Date, or whatever - only take the amount of milliseconds into consideration. They end up counting the number of 24-hour cycles between two dates, rather than the actual number of days. So something from Jan 1st 11pm to Jan 2nd 1am will return 0 days.

To count the actual number of days between startDate and endDate, simply do:

// Find the sequential day from a date, essentially resetting time to start of the day
long startDay = startDate.getTime() / 1000 / 60 / 60 / 24;
long endDay = endDate.getTime() / 1000 / 60 / 60 / 24;

// Find the difference, duh
long daysBetween = endDay - startDay;

This will return "1" between Jan 2nd and Jan 1st. If you need to count the end day, just add 1 to daysBetween (I needed to do that in my code since I wanted to count the total number of days in the range).

This is somewhat similar to what Daniel has suggested but smaller code I suppose.

How can I get a first element from a sorted list?

That depends on what type your list is, for ArrayList use:

list.get(0);

for LinkedList use:

list.getFirst();

if you like the array approach:

list.toArray()[0];

React - changing an uncontrolled input

When you first render your component, this.state.name isn't set, so it evaluates to undefined or null, and you end up passing value={undefined} or value={null}to your input.

When ReactDOM checks to see if a field is controlled, it checks to see if value != null (note that it's !=, not !==), and since undefined == null in JavaScript, it decides that it's uncontrolled.

So, when onFieldChange() is called, this.state.name is set to a string value, your input goes from being uncontrolled to being controlled.

If you do this.state = {name: ''} in your constructor, because '' != null, your input will have a value the whole time, and that message will go away.

Android Google Maps API V2 Zoom to Current Location

try this code :

private GoogleMap mMap;


LocationManager locationManager;


private static final String TAG = "";

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_maps);
    // Obtain the SupportMapFragment and get notified when the map is ready to be used.
    SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager()
            .findFragmentById(map);
    mapFragment.getMapAsync(this);

    arrayPoints = new ArrayList<LatLng>();
}

@Override
public void onMapReady(GoogleMap googleMap) {


    mMap = googleMap;


    mMap.setMapType(GoogleMap.MAP_TYPE_HYBRID);


    LatLng myPosition;


    if (ActivityCompat.checkSelfPermission(this, android.Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(this, android.Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
        // TODO: Consider calling
        //    ActivityCompat#requestPermissions
        // here to request the missing permissions, and then overriding
        //   public void onRequestPermissionsResult(int requestCode, String[] permissions,
        //                                          int[] grantResults)
        // to handle the case where the user grants the permission. See the documentation
        // for ActivityCompat#requestPermissions for more details.
        return;
    }
    googleMap.setMyLocationEnabled(true);
    LocationManager locationManager = (LocationManager) getSystemService(LOCATION_SERVICE);
    Criteria criteria = new Criteria();
    String provider = locationManager.getBestProvider(criteria, true);
    Location location = locationManager.getLastKnownLocation(provider);


    if (location != null) {
        double latitude = location.getLatitude();
        double longitude = location.getLongitude();
        LatLng latLng = new LatLng(latitude, longitude);
        myPosition = new LatLng(latitude, longitude);


        LatLng coordinate = new LatLng(latitude, longitude);
        CameraUpdate yourLocation = CameraUpdateFactory.newLatLngZoom(coordinate, 19);
        mMap.animateCamera(yourLocation);
    }
}

}

Dont forget to add permissions on AndroidManifest.xml.

<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION"/>
<uses-permission android:name="android.permission.INTERNET"/>
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION"/>

Parse RSS with jQuery

jQuery Feeds is a nice option, it has a built-in templating system and uses the Google Feed API, so it has cross-domain support.

Opening Chrome From Command Line

Have a look into the start command. It should do what you're trying to achieve.

Also, you might be able to leave out path to chrome. The following works on Windows 7:

start chrome "site1.com" "site2.com"

Running Node.Js on Android

the tutorial of how to build NodeJS for Android https://github.com/dna2github/dna2oslab/tree/master/android/build
there are several versions v0.12, v4, v6, v7

It is easy to run compiled binary on Android; for example run compiled Nginx: https://github.com/dna2github/dna2mtgol/tree/master/fileShare

You just need to modify code to replace Nginx to NodeJS; it is better if using Android Service to run node js server on the backend.

Converting ISO 8601-compliant String to java.util.Date

tl;dr

OffsetDateTime.parse ( "2010-01-01T12:00:00+01:00" )

Using java.time

The new java.time package in Java 8 and later was inspired by Joda-Time.

The OffsetDateTime class represents a moment on the timeline with an offset-from-UTC but not a time zone.

OffsetDateTime odt = OffsetDateTime.parse ( "2010-01-01T12:00:00+01:00" );

Calling toString generates a string in standard ISO 8601 format:

2010-01-01T12:00+01:00

To see the same value through the lens of UTC, extract an Instant or adjust the offset from +01:00 to 00:00.

Instant instant = odt.toInstant();  

…or…

OffsetDateTime odtUtc = odt.withOffsetSameInstant( ZoneOffset.UTC );

Adjust into a time zone if desired. A time zone is a history of offset-from-UTC values for a region, with a set of rules for handling anomalies such as Daylight Saving Time (DST). So apply a time zone rather than a mere offset whenever possible.

ZonedDateTime zonedDateTimeMontréal = odt.atZoneSameInstant( ZoneId.of( "America/Montreal" ) );

About java.time

The java.time framework is built into Java 8 and later. These classes supplant the troublesome old legacy date-time classes such as java.util.Date, Calendar, & SimpleDateFormat.

The Joda-Time project, now in maintenance mode, advises migration to the java.time classes.

To learn more, see the Oracle Tutorial. And search Stack Overflow for many examples and explanations. Specification is JSR 310.

You may exchange java.time objects directly with your database. Use a JDBC driver compliant with JDBC 4.2 or later. No need for strings, no need for java.sql.* classes.

Where to obtain the java.time classes?

  • Java SE 8, Java SE 9, Java SE 10, and later
  • Built-in.
  • Part of the standard Java API with a bundled implementation.
  • Java 9 adds some minor features and fixes.
  • Java SE 6 and Java SE 7
  • Much of the java.time functionality is back-ported to Java 6 & 7 in ThreeTen-Backport.
  • Android
  • Later versions of Android bundle implementations of the java.time classes.
  • For earlier Android (<26), the ThreeTenABP project adapts ThreeTen-Backport (mentioned above). See How to use ThreeTenABP….
  • With the help of Desugaring Some Java 8 features including java.time are supported for even earlier versions of android.

The ThreeTen-Extra project extends java.time with additional classes. This project is a proving ground for possible future additions to java.time. You may find some useful classes here such as Interval, YearWeek, YearQuarter, and more.


Using a different font with twitter bootstrap

First of all you have to include your font in your website (or your CSS, to be more specific) using an appropriate @font-face rule.
From here on there are multiple ways to proceed. One thing I would not do is to edit the bootstrap.css directly - since once you get a newer version your changes will be lost. You do however have the possibility to customize your bootstrap files (there's a customize page on their website). Just enter the name of your font with all the fallback names into the corresponding typography textbox. Of course you will have to do this whenever you get a new or updated version of your bootstrap files.
Another chance you have is to overwrite the bootstrap rules within a different stylesheet. If you do this you just have to use selectors that are as specific as (or more specific than) the bootstrap selectors.
Side note: If you care about browser support a single EOT version of your font might not be sufficient. See http://caniuse.com/eot for a support table.

Detecting an "invalid date" Date instance in JavaScript

A ready function based on top rated answer:

  /**
   * Check if date exists and is valid.
   *
   * @param {String} dateString Date in YYYY-mm-dd format.
   */
  function isValidDate(dateString) {
  var isValid = false;
  var date;

  date =
    new Date(
      dateString);

  if (
    Object.prototype.toString.call(
      date) === "[object Date]") {

    if (isNaN(date.getTime())) {

      // Date is unreal.

    } else {
      // Date is real if month and day match each other in date and string (otherwise may be shifted):
      isValid =
        date.getUTCMonth() + 1 === dateString.split("-")[1] * 1 &&
        date.getUTCDate() === dateString.split("-")[2] * 1;
    }
  } else {
    // It's not a date.
  }

  return isValid;
}

Python Error: unsupported operand type(s) for +: 'int' and 'NoneType'

In your giant elif chain, you skipped 13. You might want to throw an error if you hit the end of the chain without returning anything, to catch numbers you missed and incorrect calls of the function:

...
elif x == 90:
    return 6
else:
    raise ValueError(x)

What is the difference between ELF files and bin files?

A Bin file is a pure binary file with no memory fix-ups or relocations, more than likely it has explicit instructions to be loaded at a specific memory address. Whereas....

ELF files are Executable Linkable Format which consists of a symbol look-ups and relocatable table, that is, it can be loaded at any memory address by the kernel and automatically, all symbols used, are adjusted to the offset from that memory address where it was loaded into. Usually ELF files have a number of sections, such as 'data', 'text', 'bss', to name but a few...it is within those sections where the run-time can calculate where to adjust the symbol's memory references dynamically at run-time.

How do I change the JAVA_HOME for ant?

Though the environment variable JAVA_HOME set correctly, the ant may use the configured JRE within the each build.xml or any build files.

To check what version of the JRE the ant is using, right click on the build file -> select the build ant which displays the details about the tasks to choose etc, select the JRE which you want to use.

Its advisable to use the project level settings or just at the workspace level.

Detecting Back Button/Hash Change in URL

Another great implementation is balupton's jQuery History which will use the native onhashchange event if it is supported by the browser, if not it will use an iframe or interval appropriately for the browser to ensure all the expected functionality is successfully emulated. It also provides a nice interface to bind to certain states.

Another project worth noting as well is jQuery Ajaxy which is pretty much an extension for jQuery History to add ajax to the mix. As when you start using ajax with hashes it get's quite complicated!

How to print a certain line of a file with PowerShell?

To reduce memory consumption and to speed up the search you may use -ReadCount option of Get-Content cmdlet (https://technet.microsoft.com/ru-ru/library/hh849787.aspx).

This may save hours when you working with large files.

Here is an example:

$n = 60699010
$src = 'hugefile.csv'
$batch = 100
$timer = [Diagnostics.Stopwatch]::StartNew()

$count = 0
Get-Content $src -ReadCount $batch -TotalCount $n | %  { 
    $count += $_.Length
    if ($count -ge $n ) {
        $_[($n - $count + $_.Length - 1)]
    }
}

$timer.Stop()
$timer.Elapsed

This prints $n'th line and elapsed time.

MySQL: How to allow remote connection to mysql

That is allowed by default on MySQL.

What is disabled by default is remote root access. If you want to enable that, run this SQL command locally:

 GRANT ALL PRIVILEGES ON *.* TO 'root'@'%' IDENTIFIED BY 'password' WITH GRANT OPTION;
 FLUSH PRIVILEGES;

And then find the following line and comment it out in your my.cnf file, which usually lives on /etc/mysql/my.cnf on Unix/OSX systems. In some cases the location for the file is /etc/mysql/mysql.conf.d/mysqld.cnf).

If it's a Windows system, you can find it in the MySQL installation directory, usually something like C:\Program Files\MySQL\MySQL Server 5.5\ and the filename will be my.ini.

Change line

 bind-address = 127.0.0.1

to

 #bind-address = 127.0.0.1

And restart the MySQL server (Unix/OSX, and Windows) for the changes to take effect.

Command to escape a string in bash

It may not be quite what you want, since it's not a standard command on anyone's systems, but since my program should work fine on POSIX systems (if compiled), I'll mention it anyway. If you have the ability to compile or add programs on the machine in question, it should work.

I've used it without issue for about a year now, but it could be that it won't handle some edge cases. Most specifically, I have no idea what it would do with newlines in strings; a case for \\n might need to be added. This list of characters is not authoritative, but I believe it covers everything else.

I wrote this specifically as a 'helper' program so I could make a wrapper for things like scp commands.

It can likely be implemented as a shell function as well

I therefore present escapify.c. I use it like so:

scp user@host:"$(escapify "/this/path/needs to be escaped/file.c")" destination_file.c

PLEASE NOTE: I made this program for my own personal use. It also will (probably wrongly) assume that if it is given more than one argument that it should just print an unescaped space and continue on. This means that it can be used to pass multiple escaped arguments correctly, but could be seen as unwanted behavior by some.

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
int main(int argc, char **argv)
{
  char c='\0';
  int i=0;
  int j=1;
  /* do not care if no args passed; escaped nothing is still nothing. */
  if(argc < 2)
  {
    return 0;
  }
  while(j<argc)
  {
    while(i<strlen(argv[j]))
    {
      c=argv[j][i];
      /* this switch has no breaks on purpose. */
      switch(c)
      {
      case ';':
      case '\'':
      case ' ':
      case '!':
      case '"':
      case '#':
      case '$':
      case '&':
      case '(':
      case ')':
      case '|':
      case '*':
      case ',':
      case '<':
      case '>':
      case '[':
      case ']':
      case '\\':
      case '^':
      case '`':
      case '{':
      case '}':
        putchar('\\');
      default:
        putchar(c);
      }
      i++;
    }
    j++;
    if(j<argc) {
      putchar(' ');
    }
    i=0;
  }
  /* newline at end */
  putchar ('\n');
  return 0;
}

What is "overhead"?

It's the resources required to set up an operation. It might seem unrelated, but necessary.

It's like when you need to go somewhere, you might need a car. But, it would be a lot of overhead to get a car to drive down the street, so you might want to walk. However, the overhead would be worth it if you were going across the country.

In computer science, sometimes we use cars to go down the street because we don't have a better way, or it's not worth our time to "learn how to walk".

How to always show scrollbar

As of now the best way is to use android:fadeScrollbars="false" in xml which is equivalent to ScrollView.setScrollbarFadingEnabled(false); in java code.

What does the star operator mean, in a function call?

It is called the extended call syntax. From the documentation:

If the syntax *expression appears in the function call, expression must evaluate to a sequence. Elements from this sequence are treated as if they were additional positional arguments; if there are positional arguments x1,..., xN, and expression evaluates to a sequence y1, ..., yM, this is equivalent to a call with M+N positional arguments x1, ..., xN, y1, ..., yM.

and:

If the syntax **expression appears in the function call, expression must evaluate to a mapping, the contents of which are treated as additional keyword arguments. In the case of a keyword appearing in both expression and as an explicit keyword argument, a TypeError exception is raised.

Get file path of image on Android

In order to take a picture you have to determine a path where you would like the image saved and pass that as an extra in the intent, for example:

private void capture(){
    String directoryPath = Environment.getExternalStorageDirectory() + "/" + IMAGE_DIRECTORY + "/";
    String filePath = directoryPath+Long.toHexString(System.currentTimeMillis())+".jpg";
    File directory = new File(directoryPath);
    if (!directory.exists()) {
        directory.mkdirs();
    }
    this.capturePath = filePath; // you will process the image from this path if the capture goes well
    Intent intent = new Intent(android.provider.MediaStore.ACTION_IMAGE_CAPTURE);
    intent.putExtra( MediaStore.EXTRA_OUTPUT, Uri.fromFile( new File(filePath) ) );
    startActivityForResult(intent, REQUEST_CAPTURE);                

}

I just copied the above portion from another answer I gave.

However to warn you there are a lot of inconsitencies with image capture behavior between devices that you should look out for.

Here is an issue I ran into on some HTC devices, where it would save in the location I passed and in it's default location resulting in duplicate images on the device: Deleting a gallery image after camera intent photo taken

Eclipse "Server Locations" section disabled and need to change to use Tomcat installation

Make sure that there is no project Deploy in server. If so ,please right click on server ,select add and remove ,Then remove all project. After this you can double click on server and the option will be enabled for you.

How do I draw a set of vertical lines in gnuplot?

You can use the grid feature for the second unused axis x2, which is the most natural way of drawing a set of regular spaced lines.

set grid x2tics
set x2tics 10 format "" scale 0

In general, the grid is drawn at the same position as the tics on the axis. In case the position of the lines does not correspond to the tics position, gnuplot provides an additional set of tics, called x2tics. format "" and scale 0 hides the x2tics so you only see the grid lines.

You can style the lines as usual with linewith, linecolor.

How do I detect the Python version at runtime?

Here's some code I use with sys.version_info to check the Python installation:

def check_installation(rv):
    current_version = sys.version_info
    if current_version[0] == rv[0] and current_version[1] >= rv[1]:
        pass
    else:
        sys.stderr.write( "[%s] - Error: Your Python interpreter must be %d.%d or greater (within major version %d)\n" % (sys.argv[0], rv[0], rv[1], rv[0]) )
        sys.exit(-1)
    return 0

...

# Calling the 'check_installation' function checks if Python is >= 2.7 and < 3
required_version = (2,7)
check_installation(required_version)

Angular - ui-router get previous state

You can return the state this way:

$state.go($state.$current.parent.self.name, $state.params);

An example:

(function() {
    'use strict'

    angular.module('app')
        .run(Run);

    /* @ngInject */
    function Run($rootScope, $state) {

        $rootScope.back = function() {
            $state.go($state.$current.parent.self.name, $state.params);
        };

    };

})();

add an onclick event to a div

Is it possible to add onclick to a div and have it occur if any area of the div is clicked.

Yes … although it should be done with caution. Make sure there is some mechanism that allows keyboard access. Build on things that work

If yes then why is the onclick method not going through to my div.

You are assigning a string where a function is expected.

divTag.onclick = printWorking;

There are nicer ways to assign event handlers though, although older versions of Internet Explorer are sufficiently different that you should use a library to abstract it. There are plenty of very small event libraries and every major library jQuery) has event handling functionality.

That said, now it is 2019, older versions of Internet Explorer no longer exist in practice so you can go direct to addEventListener

Python: can't assign to literal

1, 2, 3 ,... are invalid identifiers in python because first of all they are integer objects and secondly in python a variable name can't start with a number.

>>> 1 = 12    #you can't assign to an integer
  File "<ipython-input-177-30a62b7248f1>", line 1
SyntaxError: can't assign to literal

>>> 1a = 12   #1a is an invalid variable name
  File "<ipython-input-176-f818ca46b7dc>", line 1
    1a = 12
     ^
SyntaxError: invalid syntax

Valid identifier definition:

identifier ::=  (letter|"_") (letter | digit | "_")*
letter     ::=  lowercase | uppercase
lowercase  ::=  "a"..."z"
uppercase  ::=  "A"..."Z"
digit      ::=  "0"..."9"

Fastest way to add an Item to an Array

Case C) is the fastest. Having this as an extension:

Public Module MyExtensions
    <Extension()> _
    Public Sub Add(Of T)(ByRef arr As T(), item As T)
        Array.Resize(arr, arr.Length + 1)
        arr(arr.Length - 1) = item
    End Sub
End Module

Usage:

Dim arr As Integer() = {1, 2, 3}
Dim newItem As Integer = 4
arr.Add(newItem)

' --> duration for adding 100.000 items: 1 msec
' --> duration for adding 100.000.000 items: 1168 msec

How to comment multiple lines with space or indent

Pressing Ctrl+K+C or Ctrl+E+C After selecting the lines you want to comment will not give space after slashes. you can use multiline select to provide space as suggested by Habib

Perhaps, you can use /* before the lines you want to comment and after */ in that case you might not need to provide spaces.

/*
  First Line to Comment
  Second Line to Comment
  Third Line to Comment      
*/

Can I start the iPhone simulator without "Build and Run"?

To follow up on that the new command from @jimbojw to create a shortcut with the new Xcode (installing through preferences) is:

ln -s /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/Applications/iPhone\ Simulator.app /Applications/iPhone\ Simulator.app

Which will create a shortcut in the applications folder for you.

Gridview row editing - dynamic binding to a DropDownList

 <asp:GridView ID="GridView1" runat="server" PageSize="2" AutoGenerateColumns="false"
            AllowPaging="true" BackColor="White" BorderColor="#CC9966" BorderStyle="None"
            BorderWidth="1px" CellPadding="4" OnRowEditing="GridView1_RowEditing" OnRowUpdating="GridView1_RowUpdating"
            OnPageIndexChanging="GridView1_PageIndexChanging" OnRowCancelingEdit="GridView1_RowCancelingEdit"
            OnRowDeleting="GridView1_RowDeleting">
            <FooterStyle BackColor="#FFFFCC" ForeColor="#330099" />
            <RowStyle BackColor="White" ForeColor="#330099" />
            <SelectedRowStyle BackColor="#FFCC66" Font-Bold="True" ForeColor="#663399" />
            <PagerStyle BackColor="#FFFFCC" ForeColor="#330099" HorizontalAlign="Center" />
            <HeaderStyle BackColor="#990000" Font-Bold="True" ForeColor="#FFFFCC" />
            <Columns>
            <asp:TemplateField HeaderText="SerialNo">
            <ItemTemplate>
            <%# Container .DataItemIndex+1 %>.&nbsp
            </ItemTemplate>
            </asp:TemplateField>
                <asp:TemplateField HeaderText="RollNo">
                    <ItemTemplate>
                        <%--<asp:Label ID="lblrollno" runat="server" Text='<%#Eval ("RollNo")%>'></asp:Label>--%>
                        <asp:TextBox ID="txtrollno" runat="server" Text='<%#Eval ("RollNo")%>'></asp:TextBox>
                    </ItemTemplate>
                </asp:TemplateField>
                <asp:TemplateField HeaderText="SName">
                    <ItemTemplate>
                    <%--<asp:Label ID="lblsname" runat="server" Text='<%#Eval("SName")%>'></asp:Label>--%>
                        <asp:TextBox ID="txtsname" runat="server" Text='<%#Eval("SName")%>'> </asp:TextBox>
                    </ItemTemplate>
                </asp:TemplateField>
                <asp:TemplateField HeaderText="C">
                    <ItemTemplate>
                    <%-- <asp:Label ID="lblc" runat="server" Text='<%#Eval ("C") %>'></asp:Label>--%>
                        <asp:TextBox ID="txtc" runat="server" Text='<%#Eval ("C") %>'></asp:TextBox>
                    </ItemTemplate>
                </asp:TemplateField>
                <asp:TemplateField HeaderText="Cpp">
                    <ItemTemplate>
                    <%-- <asp:Label ID="lblcpp" runat="server" Text='<%#Eval ("Cpp")%>'></asp:Label>--%>
                       <asp:TextBox ID="txtcpp" runat="server" Text='<%#Eval ("Cpp")%>'> </asp:TextBox>
                    </ItemTemplate>
                </asp:TemplateField>
                <asp:TemplateField HeaderText="Java">
                    <ItemTemplate>
                       <%--  <asp:Label ID="lbljava" runat="server" Text='<%#Eval ("Java")%>'> </asp:Label>--%>
                        <asp:TextBox ID="txtjava" runat="server" Text='<%#Eval ("Java")%>'> </asp:TextBox>
                    </ItemTemplate>
                </asp:TemplateField>
                <asp:TemplateField HeaderText="Edit" ShowHeader="False">
                    <EditItemTemplate>
                        <asp:LinkButton ID="lnkbtnUpdate" runat="server" CausesValidation="true" Text="Update"
                            CommandName="Update"></asp:LinkButton>
                        <asp:LinkButton ID="lnkbtnCancel" runat="server" CausesValidation="false" Text="Cancel"
                            CommandName="Cancel"></asp:LinkButton>
                    </EditItemTemplate>
                    <ItemTemplate>
                        <asp:LinkButton ID="btnEdit" runat="server" CausesValidation="false" CommandName="Edit"
                            Text="Edit"></asp:LinkButton>
                    </ItemTemplate>
                </asp:TemplateField>
                <asp:CommandField HeaderText="Delete" ShowDeleteButton="True" ShowHeader="True" />
                <asp:CommandField HeaderText="Select" ShowSelectButton="True" ShowHeader="True" />
            </Columns>
        </asp:GridView>
        <table>
            <tr>
                <td>
                    <asp:Label ID="lblrollno" runat="server" Text="RollNo"></asp:Label>
                    <asp:TextBox ID="txtrollno" runat="server"></asp:TextBox>
                </td>
                <td>
                    <asp:Label ID="lblsname" runat="server" Text="SName"></asp:Label>
                    <asp:TextBox ID="txtsname" runat="server"></asp:TextBox>
                </td>
                <td>
                    <asp:Label ID="lblc" runat="server" Text="C"></asp:Label>
                    <asp:TextBox ID="txtc" runat="server"></asp:TextBox>
                </td>
                <td>
                    <asp:Label ID="lblcpp" runat="server" Text="Cpp"></asp:Label>
                    <asp:TextBox ID="txtcpp" runat="server"></asp:TextBox>
                </td>
                <td>
                    <asp:Label ID="lbljava" runat="server" Text="Java"></asp:Label>
                    <asp:TextBox ID="txtjava" runat="server"></asp:TextBox>
                </td>
            </tr>
            <tr>
                <td>
                    <asp:Button ID="Submit" runat="server" Text="Submit" OnClick="Submit_Click" />
                    <asp:Button ID="Reset" runat="server" Text="Reset" OnClick="Reset_Click" />
                </td>
            </tr>
        </table>

Polynomial time and exponential time

polynomial time O(n)^k means Number of operations are proportional to power k of the size of input

exponential time O(k)^n means Number of operations are proportional to the exponent of the size of input

How to change the style of a DatePicker in android?

call like this

 button5.setOnClickListener(new View.OnClickListener() {

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

 DialogFragment dialogfragment = new DatePickerDialogTheme();

 dialogfragment.show(getFragmentManager(), "Theme");

 }
 });

public static class DatePickerDialogTheme extends DialogFragment implements DatePickerDialog.OnDateSetListener{

     @Override
     public Dialog onCreateDialog(Bundle savedInstanceState){
     final Calendar calendar = Calendar.getInstance();
     int year = calendar.get(Calendar.YEAR);
     int month = calendar.get(Calendar.MONTH);
     int day = calendar.get(Calendar.DAY_OF_MONTH);

//for one

//for two 

 DatePickerDialog datepickerdialog = new DatePickerDialog(getActivity(),
 AlertDialog.THEME_DEVICE_DEFAULT_DARK,this,year,month,day);

//for three 
 DatePickerDialog datepickerdialog = new DatePickerDialog(getActivity(),
 AlertDialog.THEME_DEVICE_DEFAULT_LIGHT,this,year,month,day);

// for four

   DatePickerDialog datepickerdialog = new DatePickerDialog(getActivity(),
 AlertDialog.THEME_HOLO_DARK,this,year,month,day);

//for five

 DatePickerDialog datepickerdialog = new DatePickerDialog(getActivity(),
     AlertDialog.THEME_HOLO_LIGHT,this,year,month,day);

//for six

 DatePickerDialog datepickerdialog = new DatePickerDialog(getActivity(),
 AlertDialog.THEME_TRADITIONAL,this,year,month,day);


     return datepickerdialog;
     }

     public void onDateSet(DatePicker view, int year, int month, int day){

     TextView textview = (TextView)getActivity().findViewById(R.id.textView1);

     textview.setText(day + ":" + (month+1) + ":" + year);

     }
     }

follow this it will give you all type date picker style(copy from this)

http://www.android-examples.com/change-datepickerdialog-theme-in-android-using-dialogfragment/

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How to display two digits after decimal point in SQL Server

You can also use below code which helps me:

select convert(numeric(10,2), column_name) as Total from TABLE_NAME

where Total is alias of the field you want.

UUID max character length

This is the perfect kind of field to define as CHAR 36, by the way, not VARCHAR 36, since each value will have the exact same length. And you'll use less storage space, since you don't need to store the data length for each value, just the value.

How do I get the path of the assembly the code is in?

I believe this would work for any kind of application:

AppDomain.CurrentDomain.RelativeSearchPath ?? AppDomain.CurrentDomain.BaseDirectory

Remove all child nodes from a parent?

You can use .empty(), like this:

$("#foo").empty();

From the docs:

Remove all child nodes of the set of matched elements from the DOM.

How do I alter the precision of a decimal column in Sql Server?

Go to enterprise manager, design table, click on your field.

Make a decimal column

In the properties at the bottom there is a precision property

When do you use Git rebase instead of Git merge?

This sentence gets it:

In general, the way to get the best of both worlds is to rebase local changes you’ve made, but haven’t shared yet, before you push them in order to clean up your story, but never rebase anything you’ve pushed somewhere.

Source: 3.6 Git Branching - Rebasing, Rebase vs. Merge

Validation error: "No validator could be found for type: java.lang.Integer"

For this type error: UnexpectedTypeException ERROR: We are trying to use incorrect Hibernate validator annotation on any bean property. For this same issue for my Springboot project( validating type 'java.lang.Integer')

The solution that worked for me is using @NotNull for Integer.

A html space is showing as %2520 instead of %20

Try this?

encodeURIComponent('space word').replace(/%20/g,'+')

Create a list from two object lists with linq

Does the following code work for your problem? I've used a foreach with a bit of linq inside to do the combining of lists and assumed that people are equal if their names match, and it seems to print the expected values out when run. Resharper doesn't offer any suggestions to convert the foreach into linq so this is probably as good as it'll get doing it this way.

public class Person
{
   public string Name { get; set; }
   public int Value { get; set; }
   public int Change { get; set; }

   public Person(string name, int value)
   {
      Name = name;
      Value = value;
      Change = 0;
   }
}


class Program
{
   static void Main(string[] args)
   {
      List<Person> list1 = new List<Person>
                              {
                                 new Person("a", 1),
                                 new Person("b", 2),
                                 new Person("c", 3),
                                 new Person("d", 4)
                              };
      List<Person> list2 = new List<Person>
                              {
                                 new Person("a", 4),
                                 new Person("b", 5),
                                 new Person("e", 6),
                                 new Person("f", 7)
                              };

      List<Person> list3 = list2.ToList();

      foreach (var person in list1)
      {
         var existingPerson = list3.FirstOrDefault(x => x.Name == person.Name);
         if (existingPerson != null)
         {
            existingPerson.Change = existingPerson.Value - person.Value;
         }
         else
         {
            list3.Add(person);
         }
      }

      foreach (var person in list3)
      {
         Console.WriteLine("{0} {1} {2} ", person.Name,person.Value,person.Change);
      }
      Console.Read();
   }
}

console.log timestamps in Chrome?

A refinement on the answer by JSmyth:

console.logCopy = console.log.bind(console);

console.log = function()
{
    if (arguments.length)
    {
        var timestamp = new Date().toJSON(); // The easiest way I found to get milliseconds in the timestamp
        var args = arguments;
        args[0] = timestamp + ' > ' + arguments[0];
        this.logCopy.apply(this, args);
    }
};

This:

  • shows timestamps with milliseconds
  • assumes a format string as first parameter to .log

Python 3: ImportError "No Module named Setuptools"

EDIT: Official setuptools dox page:

If you have Python 2 >=2.7.9 or Python 3 >=3.4 installed from python.org, you will already have pip and setuptools, but will need to upgrade to the latest version:

On Linux or OS X:

pip install -U pip setuptools 

On Windows:

python -m pip install -U pip setuptools

Therefore the rest of this post is probably obsolete (e.g. some links don't work).

Distribute - is a setuptools fork which "offers Python 3 support". Installation instructions for distribute(setuptools) + pip:

curl -O http://python-distribute.org/distribute_setup.py
python distribute_setup.py
easy_install pip

Similar issue here.

UPDATE: Distribute seems to be obsolete, i.e. merged into Setuptools: Distribute is a deprecated fork of the Setuptools project. Since the Setuptools 0.7 release, Setuptools and Distribute have merged and Distribute is no longer being maintained. All ongoing effort should reference the Setuptools project and the Setuptools documentation.

You may try with instructions found on setuptools pypi page (I haven't tested this, sorry :( ):

wget https://bitbucket.org/pypa/setuptools/raw/bootstrap/ez_setup.py -O - | python
easy_install pip

Bootstrap: Open Another Modal in Modal

I went kind of a different route all together, I decided to "De-Nest" them. Maybe someone will find this handy...

var $m1 = $('#Modal1');
var $innermodal = $m1.find(".modal");     //get reference to nested modal
$m1.after($innermodal);                  // snatch it out of inner modal and put it after.

What is a classpath and how do I set it?

The classpath in this context is exactly what it is in the general context: anywhere the VM knows it can find classes to be loaded, and resources as well (such as output.vm in your case).

I'd understand Velocity expects to find a file named output.vm anywhere in "no package". This can be a JAR, regular folder, ... The root of any of the locations in the application's classpath.

Python: Convert timedelta to int in a dataframe

If the question isn't just "how to access an integer form of the timedelta?" but "how to convert the timedelta column in the dataframe to an int?" the answer might be a little different. In addition to the .dt.days accessor you need either df.astype or pd.to_numeric

Either of these options should help:

df['tdColumn'] = pd.to_numeric(df['tdColumn'].dt.days, downcast='integer')

or

df['tdColumn'] = df['tdColumn'].dt.days.astype('int16')