Programs & Examples On #Resolver

Python DNS module import error

I have faced similar issue when importing on mac.i have python 3.7.3 installed Following steps helped me resolve it:

  1. pip3 uninstall dnspython
  2. sudo -H pip3 install dnspython

Import dns

Import dns.resolver

Jquery - How to get the style display attribute "none / block"

You could try:

$j('div.contextualError.ckgcellphone').css('display')

Find Number of CPUs and Cores per CPU using Command Prompt

Based upon your comments - your path statement has been changed/is incorrect or the path variable is being incorrectly used for another purpose.

Removing the remembered login and password list in SQL Server Management Studio

This works for SQL Server Management Studio v18.0

The file "SqlStudio.bin" doesn't seem to exist any longer. Instead my settings are all stored in this file:

C:\Users\*********\AppData\Roaming\Microsoft\SQL Server Management Studio\18.0\UserSettings.xml

  • Open it in any Texteditor like Notepad++
  • ctrl+f for the username to be removed
  • then delete the entire <Element>.......</Element> block that surrounds it.

How to call python script on excel vba?

To those who are stuck wondering why a window flashes and goes away without doing anything the python script is meant to do after calling the shell command from VBA: In my program

Sub runpython()

Dim Ret_Val
args = """F:\my folder\helloworld.py"""
Ret_Val = Shell("C:\Users\username\AppData\Local\Programs\Python\Python36\python.exe " & " " & args, vbNormalFocus)
If Ret_Val = 0 Then
   MsgBox "Couldn't run python script!", vbOKOnly
End If
End Sub

In the line args = """F:\my folder\helloworld.py""", I had to use triple quotes for this to work. If I use just regular quotes like: args = "F:\my folder\helloworld.py" the program would not work. The reason for this is that there is a space in the path (my folder). If there is a space in the path, in VBA, you need to use triple quotes.

javascript : sending custom parameters with window.open() but its not working

You can use this but there remains a security issue

<script type="text/javascript">
function fnc1()
{
    var a=window.location.href;

    username="p";
    password=1234;
    window.open(a+'?username='+username+'&password='+password,"");

}   
</script>
<input type="button" onclick="fnc1()" />
<input type="text" id="atext"  />

How to bind inverse boolean properties in WPF?

I did something very similar. I created my property behind the scenes that enabled the selection of a combobox ONLY if it had finished searching for data. When my window first appears, it launches an async loaded command but I do not want the user to click on the combobox while it is still loading data (would be empty, then would be populated). So by default the property is false so I return the inverse in the getter. Then when I'm searching I set the property to true and back to false when complete.

private bool _isSearching;
public bool IsSearching
{
    get { return !_isSearching; }
    set
    {
        if(_isSearching != value)
        {
            _isSearching = value;
            OnPropertyChanged("IsSearching");
        }
    }
}

public CityViewModel()
{
    LoadedCommand = new DelegateCommandAsync(LoadCity, LoadCanExecute);
}

private async Task LoadCity(object pArg)
{
    IsSearching = true;

    //**Do your searching task here**

    IsSearching = false;
}

private bool LoadCanExecute(object pArg)
{
    return IsSearching;
}

Then for the combobox I can bind it directly to the IsSearching:

<ComboBox ItemsSource="{Binding Cities}" IsEnabled="{Binding IsSearching}" DisplayMemberPath="City" />

Where are shared preferences stored?

I just tried to get path of shared preferences below like this.This is work for me.

File f = getDatabasePath("MyPrefsFile.xml");

if (f != null)
    Log.i("TAG", f.getAbsolutePath());

NuGet Package Restore Not Working

Automatic Package Restore will fail for any of the following reasons:

  1. You did not remove the NuGet.exe and NuGet.targets files from the solution's .nuget folder (which can be found in your solution root folder)
  2. You did not enable automatic package restore from the Tools >> Options >> Nuget Package Manager >> General settings.
  3. You forgot to manually remove references in all your projects to the Nuget.targets file
  4. You need to restart Visual Studio (make sure the process is killed from your task manager before starting up again).

The following article outlines in more detail how to go about points 1-3: https://docs.nuget.org/consume/package-restore/migrating-to-automatic-package-restore

Get $_POST from multiple checkboxes

Edit To reflect what @Marc said in the comment below.

You can do a loop through all the posted values.

HTML:

<input type="checkbox" name="check_list[]" value="<?=$rowid?>" />
<input type="checkbox" name="check_list[]" value="<?=$rowid?>" />
<input type="checkbox" name="check_list[]" value="<?=$rowid?>" />

PHP:

foreach($_POST['check_list'] as $item){
  // query to delete where item = $item
}

WAMP/XAMPP is responding very slow over localhost

I had the same problem running on Windows 8 running on 64bit. Apache is really slow but when you press F5 many times it goes ok. In the end i after doing many things managed to solve it. Right now it works fast.

Try the following tasks to increase the performance:

Change apache's listening port

Change listening port from 80 to 8080 to avoid conflicts with programs like Skype. Open your httpd.conf file and find the line that starts with Listen (it's around line 62). Change it like the following: Listen 127.0.0.1:8080

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Change your powerplan

Change your power plan from Balanced to High Performance. You can do this in Control Panel\All Control Panel Items\Power Options

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Disable IPv6

The credits of this particular task go to Jef where he pointed this out in his blog post. From the Windows 8 desktop, press the Windows Key and the R key at the same time

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Type regedit in the Run dialog box and click OK

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Use Registry Editor to expand the registry tree and browse to:

\HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\TCPIP6\Parameters

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Right click on Parameters, expand New, and select DWORD (32-bit) Value

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Enter DisabledComponents into the Name field

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Double click on the new DisabledComponents value, enter ffffffff into the Value data dialog box, and click the OK button

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Confirm the new registry value contains the required data.

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Change your etc/hosts

If you use virtual hosts don't add each virtual host on a new line. Instead list them like the following. 127.0.0.1 site-a site-b site-c

I also added 127.0.0.1 127.0.0.1 since I heard this somehow improves the lookup as well. (Can't confirm this but it can't hurt putting it there)

enter image description here

Your hosts file is located at C:\Windows\System32\Drivers\etc

Check how many apache processes are running

In my case I had two apache processes running. Be sure you only have one running. You can check this by pressing CTRL+ALT+DEL and press Task Manager

enter image description here

Turn off the Base Filtering Engine (BFE)

What I find to be working a bit as well was turning off the Base Filtering Engine. Since stopping or disabling the BFE service will significantly reduce the security of the system you should only do this when needed.

Go to Control Panel => Administrative Tools => Services => Base Filtering Engine

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Stop the Base Filtering Engine by clicking on Stop

enter image description here

Increase Apache's process priority

To to your task manager and change Apache's process priority from Normal to High by right clicking -> Set priority -> High enter image description here

Keep Apache's process busy

This is a bit of an ugly method but it does certainly work. It keeps Apache busy and will process your own requests faster. Insert your local web-address in the iframe location and save it in a html file, run it and just leave it there until you're done.

<html>
    <head>

<script>
setTimeout(function(){
   window.location.reload(1);
}, 2000);

</script>

</head>
<body>
<iframe name="iframe" id="iframe" src="http://mywebsite:8080"></iframe> 


</body>
</html>

Downgrade to Windows 7 Pro

As a Windows 8 Pro user you are entitled to have downgrade rights to Windows 7. Read here more about this. For me that was the only solution that really did the job properly.

Good luck!

How to read an http input stream

It looks like the documentation is just using readStream() to mean:

Ok, we've shown you how to get the InputStream, now your code goes in readStream()

So you should either write your own readStream() method which does whatever you wanted to do with the data in the first place.

How can I sort a std::map first by value, then by key?

As explained in Nawaz's answer, you cannot sort your map by itself as you need it, because std::map sorts its elements based on the keys only. So, you need a different container, but if you have to stick to your map, then you can still copy its content (temporarily) into another data structure.

I think, the best solution is to use a std::set storing flipped key-value pairs as presented in ks1322's answer. The std::set is sorted by default and the order of the pairs is exactly as you need it:

3) If lhs.first<rhs.first, returns true. Otherwise, if rhs.first<lhs.first, returns false. Otherwise, if lhs.second<rhs.second, returns true. Otherwise, returns false.

This way you don't need an additional sorting step and the resulting code is quite short:

std::map<std::string, int> m;  // Your original map.
m["realistically"] = 1;
m["really"]        = 8;
m["reason"]        = 4;
m["reasonable"]    = 3;
m["reasonably"]    = 1;
m["reassemble"]    = 1;
m["reassembled"]   = 1;
m["recognize"]     = 2;
m["record"]        = 92;
m["records"]       = 48;
m["recs"]          = 7;

std::set<std::pair<int, std::string>> s;  // The new (temporary) container.

for (auto const &kv : m)
    s.emplace(kv.second, kv.first);  // Flip the pairs.

for (auto const &vk : s)
    std::cout << std::setw(3) << vk.first << std::setw(15) << vk.second << std::endl;

Output:

  1  realistically
  1     reasonably
  1     reassemble
  1    reassembled
  2      recognize
  3     reasonable
  4         reason
  7           recs
  8         really
 48        records
 92         record

Code on Ideone

Note: Since C++17 you can use range-based for loops together with structured bindings for iterating over a map. As a result, the code for copying your map becomes even shorter and more readable:

for (auto const &[k, v] : m)
    s.emplace(v, k);  // Flip the pairs.

How to get current time and date in C++?

#include <stdio.h>
#include <time.h>

int main ()
{
  time_t rawtime;
  struct tm * timeinfo;

  time ( &rawtime );
  timeinfo = localtime ( &rawtime );
  printf ( "Current local time and date: %s", asctime (timeinfo) );

  return 0;
} 

How to populate a dropdownlist with json data in jquery?

To populate ComboBox with JSON, you can consider using the: jqwidgets combobox, too.

Converting xml to string using C#

There's a much simpler way to convert your XmlDocument to a string; use the OuterXml property. The OuterXml property returns a string version of the xml.

public string GetXMLAsString(XmlDocument myxml)
{
    return myxml.OuterXml;
}

How to import component into another root component in Angular 2

For Angular RC5 and RC6 you have to declare component in the module metadata decorator's declarations key, so add CoursesComponent in your main module declarations as below and remove directives from AppComponent metadata.

import { NgModule } from '@angular/core';
import { BrowserModule } from '@angular/platform-browser';

import { AppComponent } from './app.component';
import { CoursesComponent } from './courses.component';

@NgModule({
  imports:      [ BrowserModule ],
  declarations: [ AppComponent, CoursesComponent ],
  bootstrap:    [ AppComponent ]
})
export class AppModule { }

Output a NULL cell value in Excel

I've been frustrated by this problem as well. Find/Replace can be helpful though, because if you don't put anything in the "replace" field it will replace with an -actual- NULL. So the steps would be something along the lines of:

1: Place some unique string in your formula in place of the NULL output (i like to use a password-like string)

2: Run your formula

3: Open Find/Replace, and fill in the unique string as the search value. Leave "replace with" blank

4: Replace All

Obviously, this has limitations. It only works when the context allows you to do a find/replace, so for more dynamic formulas this won't help much. But, I figured I'd put it up here anyway.

Security of REST authentication schemes

REST means working with the standards of the web, and the standard for "secure" transfer on the web is SSL. Anything else is going to be kind of funky and require extra deployment effort for clients, which will have to have encryption libraries available.

Once you commit to SSL, there's really nothing fancy required for authentication in principle. You can again go with web standards and use HTTP Basic auth (username and secret token sent along with each request) as it's much simpler than an elaborate signing protocol, and still effective in the context of a secure connection. You just need to be sure the password never goes over plain text; so if the password is ever received over a plain text connection, you might even disable the password and mail the developer. You should also ensure the credentials aren't logged anywhere upon receipt, just as you wouldn't log a regular password.

HTTP Digest is a safer approach as it prevents the secret token being passed along; instead, it's a hash the server can verify on the other end. Though it may be overkill for less sensitive applications if you've taken the precautions mentioned above. After all, the user's password is already transmitted in plain-text when they log in (unless you're doing some fancy JavaScript encryption in the browser), and likewise their cookies on each request.

Note that with APIs, it's better for the client to be passing tokens - randomly generated strings - instead of the password the developer logs into the website with. So the developer should be able to log into your site and generate new tokens that can be used for API verification.

The main reason to use a token is that it can be replaced if it's compromised, whereas if the password is compromised, the owner could log into the developer's account and do anything they want with it. A further advantage of tokens is you can issue multiple tokens to the same developers. Perhaps because they have multiple apps or because they want tokens with different access levels.

(Updated to cover implications of making the connection SSL-only.)

What is an IIS application pool?

Basically, an application pool is a way to create compartments in a web server through process boundaries, and route sets of URLs to each of these compartments. See more info here: http://technet.microsoft.com/en-us/library/cc735247(WS.10).aspx

@selector() in Swift?

Using #selector will check your code at compile time to make sure the method you want to call actually exists. Even better, if the method doesn’t exist, you’ll get a compile error: Xcode will refuse to build your app, thus banishing to oblivion another possible source of bugs.

override func viewDidLoad() {
        super.viewDidLoad()

        navigationItem.rightBarButtonItem =
            UIBarButtonItem(barButtonSystemItem: .Add, target: self,
                            action: #selector(addNewFireflyRefernce))
    }

    func addNewFireflyReference() {
        gratuitousReferences.append("Curse your sudden but inevitable betrayal!")
    }

How to run cron job every 2 hours

To Enter into crontab :

crontab -e

write this into the file:

0 */2 * * * python/php/java yourfilepath

Example :0 */2 * * * python ec2-user/home/demo.py

and make sure you have keep one blank line after the last cron job in your crontab file

Postgres Error: More than one row returned by a subquery used as an expression

This means your nested SELECT returns more than one rows.

You need to add a proper WHERE clause to it.

NullPointerException: Attempt to invoke virtual method 'int java.util.ArrayList.size()' on a null object reference

Change

 mAdapter = new RecordingsListAdapter(this, recordings);

to

 mAdapter = new RecordingsListAdapter(getActivity(), recordings);

and also make sure that recordings!=null at mAdapter = new RecordingsListAdapter(this, recordings);

Calculate Pandas DataFrame Time Difference Between Two Columns in Hours and Minutes

  • How do I convert my results to only hours and minutes
    • The accepted answer only returns days + hours. Minutes are not included.
  • To provide a column that has hours and minutes, as hh:mm or x hours y minutes, would require additional calculations and string formatting.
  • This answer shows how to get either total hours or total minutes as a float, using timedelta math, and is faster than using .astype('timedelta64[h]')
  • Pandas Time Deltas User Guide
  • Pandas Time series / date functionality User Guide
  • python timedelta objects: See supported operations.
  • The following sample data is already a datetime64[ns] dtype. It is required that all relevant columns are converted using pandas.to_datetime().
import pandas as pd

# test data from OP, with values already in a datetime format
data = {'to_date': [pd.Timestamp('2014-01-24 13:03:12.050000'), pd.Timestamp('2014-01-27 11:57:18.240000'), pd.Timestamp('2014-01-23 10:07:47.660000')],
        'from_date': [pd.Timestamp('2014-01-26 23:41:21.870000'), pd.Timestamp('2014-01-27 15:38:22.540000'), pd.Timestamp('2014-01-23 18:50:41.420000')]}

# test dataframe; the columns must be in a datetime format; use pandas.to_datetime if needed
df = pd.DataFrame(data)

# add a timedelta column if wanted. It's added here for information only
# df['time_delta_with_sub'] = df.from_date.sub(df.to_date)  # also works
df['time_delta'] = (df.from_date - df.to_date)

# create a column with timedelta as total hours, as a float type
df['tot_hour_diff'] = (df.from_date - df.to_date) / pd.Timedelta(hours=1)

# create a colume with timedelta as total minutes, as a float type
df['tot_mins_diff'] = (df.from_date - df.to_date) / pd.Timedelta(minutes=1)

# display(df)
                  to_date               from_date             time_delta  tot_hour_diff  tot_mins_diff
0 2014-01-24 13:03:12.050 2014-01-26 23:41:21.870 2 days 10:38:09.820000      58.636061    3518.163667
1 2014-01-27 11:57:18.240 2014-01-27 15:38:22.540 0 days 03:41:04.300000       3.684528     221.071667
2 2014-01-23 10:07:47.660 2014-01-23 18:50:41.420 0 days 08:42:53.760000       8.714933     522.896000

Other methods

  • An item of note from the podcast in Other Resources, .total_seconds() was added and merged when the core developer was on vacation, and would not have been approved.
    • This is also why there aren't other .total_xx methods.
# convert the entire timedelta to seconds
# this is the same as td / timedelta(seconds=1)
(df.from_date - df.to_date).dt.total_seconds()
[out]:
0    211089.82
1     13264.30
2     31373.76
dtype: float64

# get the number of days
(df.from_date - df.to_date).dt.days
[out]:
0    2
1    0
2    0
dtype: int64

# get the seconds for hours + minutes + seconds, but not days
# note the difference from total_seconds
(df.from_date - df.to_date).dt.seconds
[out]:
0    38289
1    13264
2    31373
dtype: int64

Other Resources

%%timeit test

import pandas as pd

# dataframe with 2M rows
data = {'to_date': [pd.Timestamp('2014-01-24 13:03:12.050000'), pd.Timestamp('2014-01-27 11:57:18.240000')], 'from_date': [pd.Timestamp('2014-01-26 23:41:21.870000'), pd.Timestamp('2014-01-27 15:38:22.540000')]}
df = pd.DataFrame(data)
df = pd.concat([df] * 1000000).reset_index(drop=True)

%%timeit
(df.from_date - df.to_date) / pd.Timedelta(hours=1)
[out]:
43.1 ms ± 1.05 ms per loop (mean ± std. dev. of 7 runs, 10 loops each)

%%timeit
(df.from_date - df.to_date).astype('timedelta64[h]')
[out]:
59.8 ms ± 1.29 ms per loop (mean ± std. dev. of 7 runs, 10 loops each)

How to configure heroku application DNS to Godaddy Domain?

Yes, many changes at Heroku. If you're using a Heroku dyno for your webserver, you have to find way to alias from one DNS name to another DNS name (since each Heroku DNS endpoint may resolve to many IP addrs to dynamically adjust to request loads).

A CNAME record is for aliasing www.example.com -> www.example.com.herokudns.com.

You can't use CNAME for a naked domain (@), i.e. example.com (unless you find a name server that can do CNAME Flattening - which is what I did).

But really the easiest solution, that can pretty much be taken care of all in your GoDaddy account, is to create a CNAME record that does this: www.example.com -> www.example.com.herokudns.com.

And then create a permanent 301 redirect from example.com to www.example.com.

This requires only one heroku custom domain name configured in your heroku app settings: www.example.com.herokudns.com. @Jonathan Roy talks about this (above) but provides a bad link.

How to count certain elements in array?

Weirdest way I can think of doing this is:

(a.length-(' '+a.join(' ')+' ').split(' '+n+' ').join(' ').match(/ /g).length)+1

Where:

  • a is the array
  • n is the number to count in the array

My suggestion, use a while or for loop ;-)

Image height and width not working?

You must write

<img src="theSource" style="width:30px;height:30px;" />

Inline styling will always take precedence over CSS styling. The width and height attributes are being overridden by your stylesheet, so you need to switch to this format.

'Framework not found' in Xcode

Besides from removing the framework from the Podfile and Linked Frameworks and Libraries, I also had to remove the reference to the framework in Other Linker Flags.

100% height minus header?

If your browser supports CSS3, try using the CSS element Calc()

height: calc(100% - 65px);

you might also want to adding browser compatibility options:

height: -o-calc(100% - 65px); /* opera */
height: -webkit-calc(100% - 65px); /* google, safari */
height: -moz-calc(100% - 65px); /* firefox */

also make sure you have spaces between values, see: https://stackoverflow.com/a/16291105/427622

MySQL: Curdate() vs Now()

For questions like this, it is always worth taking a look in the manual first. Date and time functions in the mySQL manual

CURDATE() returns the DATE part of the current time. Manual on CURDATE()

NOW() returns the date and time portions as a timestamp in various formats, depending on how it was requested. Manual on NOW().

Functional style of Java 8's Optional.ifPresent and if-not-Present?

There isn't a great way to do it out of the box. If you want to be using your cleaner syntax on a regular basis, then you can create a utility class to help out:

public class OptionalEx {
    private boolean isPresent;

    private OptionalEx(boolean isPresent) {
        this.isPresent = isPresent;
    }

    public void orElse(Runnable runner) {
        if (!isPresent) {
            runner.run();
        }
    }

    public static <T> OptionalEx ifPresent(Optional<T> opt, Consumer<? super T> consumer) {
        if (opt.isPresent()) {
            consumer.accept(opt.get());
            return new OptionalEx(true);
        }
        return new OptionalEx(false);
    }
}

Then you can use a static import elsewhere to get syntax that is close to what you're after:

import static com.example.OptionalEx.ifPresent;

ifPresent(opt, x -> System.out.println("found " + x))
    .orElse(() -> System.out.println("NOT FOUND"));

Edit seaborn legend

If legend_out is set to True then legend is available thought g._legend property and it is a part of a figure. Seaborn legend is standard matplotlib legend object. Therefore you may change legend texts like:

import seaborn as sns

tips = sns.load_dataset("tips")
g = sns.lmplot(x="total_bill", y="tip", hue="smoker",
 data=tips, markers=["o", "x"], legend_out = True)

# title
new_title = 'My title'
g._legend.set_title(new_title)
# replace labels
new_labels = ['label 1', 'label 2']
for t, l in zip(g._legend.texts, new_labels): t.set_text(l)

sns.plt.show()

enter image description here

Another situation if legend_out is set to False. You have to define which axes has a legend (in below example this is axis number 0):

import seaborn as sns

tips = sns.load_dataset("tips")
g = sns.lmplot(x="total_bill", y="tip", hue="smoker",
 data=tips, markers=["o", "x"], legend_out = False)

# check axes and find which is have legend
leg = g.axes.flat[0].get_legend()
new_title = 'My title'
leg.set_title(new_title)
new_labels = ['label 1', 'label 2']
for t, l in zip(leg.texts, new_labels): t.set_text(l)
sns.plt.show()

enter image description here

Moreover you may combine both situations and use this code:

import seaborn as sns

tips = sns.load_dataset("tips")
g = sns.lmplot(x="total_bill", y="tip", hue="smoker",
 data=tips, markers=["o", "x"], legend_out = True)

# check axes and find which is have legend
for ax in g.axes.flat:
    leg = g.axes.flat[0].get_legend()
    if not leg is None: break
# or legend may be on a figure
if leg is None: leg = g._legend

# change legend texts
new_title = 'My title'
leg.set_title(new_title)
new_labels = ['label 1', 'label 2']
for t, l in zip(leg.texts, new_labels): t.set_text(l)

sns.plt.show()

This code works for any seaborn plot which is based on Grid class.

How can I account for period (AM/PM) using strftime?

You used %H (24 hour format) instead of %I (12 hour format).

Angular 2 router no base href set

With angular 4 you can fix this issue by updating app.module.ts file as follows:

Add import statement at the top as below:

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

And add below line inside @NgModule

providers: [{provide: APP_BASE_HREF, useValue: '/my/app'}]

Reff: https://angular.io/api/common/APP_BASE_HREF

How do I sort an NSMutableArray with custom objects in it?

I just done multi level sorting based on custom requirement.

//sort the values

    [arrItem sortUsingComparator:^NSComparisonResult (id a, id b){

    ItemDetail * itemA = (ItemDetail*)a;
    ItemDetail* itemB =(ItemDetail*)b;

    //item price are same
    if (itemA.m_price.m_selling== itemB.m_price.m_selling) {

        NSComparisonResult result=  [itemA.m_itemName compare:itemB.m_itemName];

        //if item names are same, then monogramminginfo has to come before the non monograme item
        if (result==NSOrderedSame) {

            if (itemA.m_monogrammingInfo) {
                return NSOrderedAscending;
            }else{
                return NSOrderedDescending;
            }
        }
        return result;
    }

    //asscending order
    return itemA.m_price.m_selling > itemB.m_price.m_selling;
}];

https://sites.google.com/site/greateindiaclub/mobil-apps/ios/multilevelsortinginiosobjectivec

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

There is a service called "SQL Server Browser" that provides SQL Server connection information to clients.

In my case, none of the existing solutions worked because this service was not running. I resumed it and everything went back to working perfectly.

How to provide password to a command that prompts for one in bash?

Secure commands will not allow this, and rightly so, I'm afraid - it's a security hole you could drive a truck through.

If your command does not allow it using input redirection, or a command-line parameter, or a configuration file, then you're going to have to resort to serious trickery.

Some applications will actually open up /dev/tty to ensure you will have a hard time defeating security. You can get around them by temporarily taking over /dev/tty (creating your own as a pipe, for example) but this requires serious privileges and even it can be defeated.

How to convert char to int?

int val = '1' - '0';

This can be done using ascii codes where '0' is the lowest and the number characters count up from there

Allow only numeric value in textbox using Javascript

Here is a solution which blocks all non numeric input from being entered into the text-field.

html

<input type="text" id="numbersOnly" />

javascript

var input = document.getElementById('numbersOnly');
input.onkeydown = function(e) {
    var k = e.which;
    /* numeric inputs can come from the keypad or the numeric row at the top */
    if ( (k < 48 || k > 57) && (k < 96 || k > 105)) {
        e.preventDefault();
        return false;
    }
};?

How do I get a list of installed CPAN modules?

cd /the/lib/dir/of/your/perl/installation
perldoc $(find . -name perllocal.pod)

Windows users just do a Windows Explorer search to find it.

How to configure Fiddler to listen to localhost?

The Light,

You can configure the process acting as the client to use fiddler as a proxy.

Fiddler sets itself up as a proxy conveniently on 127.0.0.1:8888, and by default overrides the system settings under Internet Options in the Control Panel (if you've configured any) such that all traffic from the common protocols (http, https, and ftp) goes to 127.0.0.1:8888 before leaving your machine.

Now these protocols are often from common processes such as browsers, and so are easily picked up by fiddler. However, in your case, the process initiating the requests is probably not a browser, but one for a programming language like php.exe, or java.exe, or whatever language you are using.

If, say, you're using php, you can leverage curl. Ensure that the curl module is enabled, and then right before your code that invokes the request, include:

curl_setopt($ch, CURLOPT_PROXY, '127.0.0.1:8888');

Hope this helps. You can also always lookup stuff like so from the fiddler documentation for a basis for you to build upon e.g. http://docs.telerik.com/fiddler/Configure-Fiddler/Tasks/ConfigurePHPcURL

Status bar and navigation bar appear over my view's bounds in iOS 7

Swift 3 / Swift 4 solution that also works with NIBs/XIB files in iOS 10+:

override func viewDidLoad() {
    super.viewDidLoad()

    edgesForExtendedLayout = []
}

How to check if element exists using a lambda expression?

The above answers require you to malloc a new stream object.

public <T>
boolean containsByLambda(Collection<? extends T> c, Predicate<? super T> p) {

    for (final T z : c) {
        if (p.test(z)) {
            return true;
        }
    }
    return false;
}

public boolean containsTabById(TabPane tabPane, String id) {
    return containsByLambda(tabPane.getTabs(), z -> z.getId().equals(id));
}
...
if (containsTabById(tabPane, idToCheck))) {
   ...
}

List and kill at jobs on UNIX

You should be able to find your command with a ps variant like:

ps -ef
ps -fubob # if your job's user ID is bob.

Then, once located, it should be a simple matter to use kill to kill the process (permissions permitting).

If you're talking about getting rid of jobs in the at queue (that aren't running yet), you can use atq to list them and atrm to get rid of them.

MySQL : transaction within a stored procedure

Take a look at http://dev.mysql.com/doc/refman/5.0/en/declare-handler.html

Basically you declare error handler which will call rollback

START TRANSACTION;

DECLARE EXIT HANDLER FOR SQLEXCEPTION 
    BEGIN
        ROLLBACK;
        EXIT PROCEDURE;
    END;
COMMIT;

ie8 var w= window.open() - "Message: Invalid argument."

Actually a name can be used however it cannot have spaces so window.open("../myPage","MyWindows",...) should work with no problem (window.open).

Increasing (or decreasing) the memory available to R processes

In RStudio, to increase:

file.edit(file.path("~", ".Rprofile"))

then in .Rprofile type this and save

invisible(utils::memory.limit(size = 60000))

To decrease: open .Rprofile

invisible(utils::memory.limit(size = 30000))

save and restart RStudio.

How to find the length of an array in shell?

Assuming bash:

~> declare -a foo
~> foo[0]="foo"
~> foo[1]="bar"
~> foo[2]="baz"
~> echo ${#foo[*]}
3

So, ${#ARRAY[*]} expands to the length of the array ARRAY.

tkinter: Open a new window with a button prompt

Here's the nearly shortest possible solution to your question. The solution works in python 3.x. For python 2.x change the import to Tkinter rather than tkinter (the difference being the capitalization):

import tkinter as tk
#import Tkinter as tk  # for python 2
    
def create_window():
    window = tk.Toplevel(root)

root = tk.Tk()
b = tk.Button(root, text="Create new window", command=create_window)
b.pack()

root.mainloop()

This is definitely not what I recommend as an example of good coding style, but it illustrates the basic concepts: a button with a command, and a function that creates a window.

How to parse SOAP XML?

First, we need to filter the XML so as to parse that into an object

$response = strtr($xml_string, ['</soap:' => '</', '<soap:' => '<']);
$output = json_decode(json_encode(simplexml_load_string($response)));
var_dump($output->Body->PaymentNotification->payment);

Check if selected dropdown value is empty using jQuery

Try this it will work --

if($('#EventStartTimeMin').val() === " ") {

    alert("Please enter start time!");

}

TypeLoadException says 'no implementation', but it is implemented

In addition to what the asker's own answer already stated, it may be worth noting the following. The reason this happens is because it is possible for a class to have a method with the same signature as an interface method without implementing that method. The following code illustrates that:

public interface IFoo
{
    void DoFoo();
}

public class Foo : IFoo
{
    public void DoFoo() { Console.WriteLine("This is _not_ the interface method."); }
    void IFoo.DoFoo() { Console.WriteLine("This _is_ the interface method."); }
}

Foo foo = new Foo();
foo.DoFoo();               // This calls the non-interface method
IFoo foo2 = foo;
foo2.DoFoo();              // This calls the interface method

Python: find position of element in array

There is a built in method for doing this:

numpy.where()

You can find out more about it in the excellent detailed documentation.

View not attached to window manager crash

Firstly,the crash reason is decorView's index is -1,we can knew it from Android source code ,there is code snippet:

class:android.view.WindowManagerGlobal

file:WindowManagerGlobal.java

private int findViewLocked(View view, boolean required) {
        final int index = mViews.indexOf(view);
//here, view is decorView,comment by OF
        if (required && index < 0) {
            throw new IllegalArgumentException("View=" + view + " not attached to window manager");
        }
        return index;
    }

so we get follow resolution,just judge decorView's index,if it more than 0 then continue or just return and give up dismiss,code as follow:

try {
            Class<?> windowMgrGloable = Class.forName("android.view.WindowManagerGlobal");
            try {
                Method mtdGetIntance = windowMgrGloable.getDeclaredMethod("getInstance");
                mtdGetIntance.setAccessible(true);
                try {
                    Object windownGlobal = mtdGetIntance.invoke(null,null);
                    try {
                        Field mViewField = windowMgrGloable.getDeclaredField("mViews");
                        mViewField.setAccessible(true);
                        ArrayList<View> mViews = (ArrayList<View>) mViewField.get(windownGlobal);
                        int decorViewIndex = mViews.indexOf(pd.getWindow().getDecorView());
                        Log.i(TAG,"check index:"+decorViewIndex);
                        if (decorViewIndex < 0) {
                            return;
                        }
                    } catch (NoSuchFieldException e) {
                        e.printStackTrace();
                    }
                } catch (IllegalAccessException e) {
                    e.printStackTrace();
                } catch (InvocationTargetException e) {
                    e.printStackTrace();
                }
            } catch (NoSuchMethodException e) {
                e.printStackTrace();
            }
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        }
        if (pd.isShowing()) {
            pd.dismiss();
        }

"application blocked by security settings" prevent applets running using oracle SE 7 update 51 on firefox on Linux mint

I had this issue. The security settings in the ControlPanel seem to be user specific. Try running it as the user you are actually running your browser as (you are not browsing as root!??) and setting the security level to Medium there. - For me, that did it.

Call ASP.NET function from JavaScript?

Regarding:

var button = document.getElementById(/* Button client id */);

button.click();

It should be like:

var button = document.getElementById('<%=formID.ClientID%>');

Where formID is the ASP.NET control ID in the .aspx file.

How can an html element fill out 100% of the remaining screen height, using css only?

The best solution I found so far is setting a footer element at the bottom of the page and then evaluate the difference of the offset of the footer and the element we need to expand. e.g.

The html file

<div id="contents"></div>
<div id="footer"></div>

The css file

#footer {
    position: fixed;
    bottom: 0;
    width: 100%;
}

The js file (using jquery)

var contents = $('#contents'); 
var footer = $('#footer');
contents.css('height', (footer.offset().top - contents.offset().top) + 'px');

You might also like to update the height of the contents element on each window resize, so...

$(window).on('resize', function() {
  contents.css('height', (footer.offset().top -contents.offset().top) + 'px');
});

How do I force git pull to overwrite everything on every pull?

If you haven't commit the local changes yet since the last pull/clone, you can use:

git checkout *
git pull

checkout will clear your local changes with the last local commit, and pull will sincronize it to the remote repository

indexOf Case Sensitive?

Yes, it is case-sensitive. You can do a case-insensitive indexOf by converting your String and the String parameter both to upper-case before searching.

String str = "Hello world";
String search = "hello";
str.toUpperCase().indexOf(search.toUpperCase());

Note that toUpperCase may not work in some circumstances. For instance this:

String str = "Feldbergstraße 23, Mainz";
String find = "mainz";
int idxU = str.toUpperCase().indexOf (find.toUpperCase ());
int idxL = str.toLowerCase().indexOf (find.toLowerCase ());

idxU will be 20, which is wrong! idxL will be 19, which is correct. What's causing the problem is tha toUpperCase() converts the "ß" character into TWO characters, "SS" and this throws the index off.

Consequently, always stick with toLowerCase()

How can I use MS Visual Studio for Android Development?

You can use Visual Studio for Android Development. See a nice article on it here

Maintaining Session through Angular.js

Here is a kind of snippet for you:

app.factory('Session', function($http) {
  var Session = {
    data: {},
    saveSession: function() { /* save session data to db */ },
    updateSession: function() { 
      /* load data from db */
      $http.get('session.json').then(function(r) { return Session.data = r.data;});
    }
  };
  Session.updateSession();
  return Session; 
});

Here is Plunker example how you can use that: http://plnkr.co/edit/Fg3uF4ukl5p88Z0AeQqU?p=preview

Can I delete a git commit but keep the changes?

2020 Simple way :

git reset <commit_hash>

(The commit hash of the last commit you want to keep).

If the commit was pushed, you can then do :

git push -f

You will keep the now uncommitted changes locally

TreeMap sort by value

Olof's answer is good, but it needs one more thing before it's perfect. In the comments below his answer, dacwe (correctly) points out that his implementation violates the Compare/Equals contract for Sets. If you try to call contains or remove on an entry that's clearly in the set, the set won't recognize it because of the code that allows entries with equal values to be placed in the set. So, in order to fix this, we need to test for equality between the keys:

static <K,V extends Comparable<? super V>> SortedSet<Map.Entry<K,V>> entriesSortedByValues(Map<K,V> map) {
    SortedSet<Map.Entry<K,V>> sortedEntries = new TreeSet<Map.Entry<K,V>>(
        new Comparator<Map.Entry<K,V>>() {
            @Override public int compare(Map.Entry<K,V> e1, Map.Entry<K,V> e2) {
                int res = e1.getValue().compareTo(e2.getValue());
                if (e1.getKey().equals(e2.getKey())) {
                    return res; // Code will now handle equality properly
                } else {
                    return res != 0 ? res : 1; // While still adding all entries
                }
            }
        }
    );
    sortedEntries.addAll(map.entrySet());
    return sortedEntries;
}

"Note that the ordering maintained by a sorted set (whether or not an explicit comparator is provided) must be consistent with equals if the sorted set is to correctly implement the Set interface... the Set interface is defined in terms of the equals operation, but a sorted set performs all element comparisons using its compareTo (or compare) method, so two elements that are deemed equal by this method are, from the standpoint of the sorted set, equal." (http://docs.oracle.com/javase/6/docs/api/java/util/SortedSet.html)

Since we originally overlooked equality in order to force the set to add equal valued entries, now we have to test for equality in the keys in order for the set to actually return the entry you're looking for. This is kinda messy and definitely not how sets were intended to be used - but it works.

Retrieving data from a POST method in ASP.NET

You need to examine (put a breakpoint on / Quick Watch) the Request object in the Page_Load method of your Test.aspx.cs file.

ssh_exchange_identification: Connection closed by remote host under Git bash

I experienced this today and I just do a:

12345@123456 MINGW64 ~/development/workspace/test (develop)
$ git status
Refresh index: 100% (1204/1204), done.
On branch develop
Your branch is up to date with 'origin/develop'.

nothing to commit, working tree clean

12345@123456 MINGW64 ~/development/workspace/test (develop)
$ git fetch

Then all worked again.

HashMap with multiple values under the same key

String key= "services_servicename"

ArrayList<String> data;

for(int i = 0; i lessthen data.size(); i++) {
    HashMap<String, String> servicesNameHashmap = new HashMap<String, String>();
    servicesNameHashmap.put(key,data.get(i).getServiceName());
    mServiceNameArray.add(i,servicesNameHashmap);
}

I have got the Best Results.

You just have to create new HashMap like

HashMap<String, String> servicesNameHashmap = new HashMap<String, String>();

in your for loop. It will have same effect like same key and multiple values.

Amazon S3 boto - how to create a folder?

S3 doesn't have a folder structure, But there is something called as keys.

We can create /2013/11/xyz.xls and will be shown as folder's in the console. But the storage part of S3 will take that as the file name.

Even when retrieving we observe that we can see files in particular folder (or keys) by using the ListObjects method and using the Prefix parameter.

Spring @Value is not resolving to value from property file

Please note that if you have multiple application.properties files throughout your codebase, then try adding your value to the parent project's property file.

You can check your project's pom.xml file to identify what the parent project of your current project is.

Alternatively, try using environment.getProperty() instead of @Value.

Android - How to achieve setOnClickListener in Kotlin?

   button.setOnClickListener {
          //write your code here
   }

Java: How to access methods from another class

You either need to create an object of type Beta in the Alpha class or its method

Like you do here in the Main Beta cBeta = new Beta();

If you want to use the variable you create in your Main then you have to parse it to cAlpha as a parameter by making the Alpha constructor look like

public class Alpha 
{

    Beta localInstance;

    public Alpha(Beta _beta)
    {
        localInstance = _beta;
    }


     public void DoSomethingAlpha() 
     {
          localInstance.DoSomethingAlpha();     
     }
}

How to get share counts using graph API

You can use the https://graph.facebook.com/v3.0/{Place_your_Page_ID here}/feed?fields=id,shares,share_count&access_token={Place_your_access_token_here} to get the shares count.

How to analyze disk usage of a Docker container

(this answer is not useful, but leaving it here since some of the comments may be)

docker images will show the 'virtual size', i.e. how much in total including all the lower layers. So some double-counting if you have containers that share the same base image.

documentation

Jquery in React is not defined

It happens mostly when JQuery is not installed in your project. Install JQuery in your project by following commands according to your package manager.

Yarn

yarn add jquery

npm

npm i jquery --save

After this just import $ in your project file. import $ from 'jquery'

Best way to store password in database

In your scenario, you can have a look at asp.net membership, it is good practice to store user's password as hashed string in the database. you can authenticate the user by comparing the hashed incoming password with the one stored in the database.

Everything has been built for this purposes, check out asp.net membership

Create list or arrays in Windows Batch

@echo off

set array=

setlocal ENABLEEXTENSIONS ENABLEDELAYEDEXPANSION

set nl=^&echo(

set array=auto blue ^!nl!^
  bycicle green ^!nl!^
  buggy   red

echo convert the String in indexed arrays

set /a index=0

for /F "tokens=1,2,3*" %%a in ( 'echo(!array!' ) do (

 echo(vehicle[!index!]=%%a color[!index!]=%%b 
 set vehicle[!index!]=%%a
 set color[!index!]=%%b
 set /a index=!index!+1   

)

echo use the arrays

echo(%vehicle[1]% %color[1]%
echo oder

set index=1
echo(!vehicle[%index%]! !color[%index%]!

How can I get relative path of the folders in my android project?

With System.getProperty("user.dir") you get the "Base of non-absolute paths" look at

Java Library Description

Using querySelectorAll to retrieve direct children

I am just doing this without even trying it. Would this work?

myDiv = getElementById("myDiv");
myDiv.querySelectorAll(this.id + " > .foo");

Give it a try, maybe it works maybe not. Apolovies, but I am not on a computer now to try it (responding from my iPhone).

How to consume a webApi from asp.net Web API to store result in database?

For some unexplained reason this solution doesn't work for me (maybe some incompatibility of types), so I came up with a solution for myself:

HttpResponseMessage response = await client.GetAsync("api/yourcustomobjects");
if (response.IsSuccessStatusCode)
{
    var data = await response.Content.ReadAsStringAsync();
    var product = JsonConvert.DeserializeObject<Product>(data);
}

This way my content is parsed into a JSON string and then I convert it to my object.

How to trigger a build only if changes happen on particular set of files

If you are using a declarative syntax of Jenkinsfile to describe your building pipeline, you can use changeset condition to limit stage execution only to the case when specific files are changed. This is now a standard feature of Jenkins and does not require any additional configruation/software.

stages {
    stage('Nginx') {
        when { changeset "nginx/*"}
        steps {
            sh "make build-nginx"
            sh "make start-nginx"
        }
    }
}

You can combine multiple conditions using anyOf or allOf keywords for OR or AND behaviour accordingly:

when {
    anyOf {
        changeset "nginx/**"
        changeset "fluent-bit/**"
    }
}
steps {
    sh "make build-nginx"
    sh "make start-nginx"
}

extracting days from a numpy.timedelta64 value

You can convert it to a timedelta with a day precision. To extract the integer value of days you divide it with a timedelta of one day.

>>> x = np.timedelta64(2069211000000000, 'ns')
>>> days = x.astype('timedelta64[D]')
>>> days / np.timedelta64(1, 'D')
23

Or, as @PhillipCloud suggested, just days.astype(int) since the timedelta is just a 64bit integer that is interpreted in various ways depending on the second parameter you passed in ('D', 'ns', ...).

You can find more about it here.

Add a auto increment primary key to existing table in oracle

Snagged from Oracle OTN forums

Use alter table to add column, for example:

alter table tableName add(columnName NUMBER);

Then create a sequence:

CREATE SEQUENCE SEQ_ID
START WITH 1
INCREMENT BY 1
MAXVALUE 99999999
MINVALUE 1
NOCYCLE;

and, the use update to insert values in column like this

UPDATE tableName SET columnName = seq_test_id.NEXTVAL

Include another JSP file

What you're doing is a static include. A static include is resolved at compile time, and may thus not use a parameter value, which is only known at execution time.

What you need is a dynamic include:

<jsp:include page="..." />

Note that you should use the JSP EL rather than scriptlets. It also seems that you're implementing a central controller with index.jsp. You should use a servlet to do that instead, and dispatch to the appropriate JSP from this servlet. Or better, use an existing MVC framework like Stripes or Spring MVC.

How can I login to a website with Python?

Websites in general can check authorization in many different ways, but the one you're targeting seems to make it reasonably easy for you.

All you need is to POST to the auth/login URL a form-encoded blob with the various fields you see there (forget the labels for, they're decoration for human visitors). handle=whatever&password-clear=pwd and so on, as long as you know the values for the handle (AKA email) and password you should be fine.

Presumably that POST will redirect you to some "you've successfully logged in" page with a Set-Cookie header validating your session (be sure to save that cookie and send it back on further interaction along the session!).

Recommended add-ons/plugins for Microsoft Visual Studio

VSCommands 2010

from the website: Latest version supports:

  • Manage Reference Paths
  • Prevent accidental Drag & Drop in Solution Explorer
  • Prevent accidental linked file delete
  • Apply Fix (automatically fix build errors/warnings)
  • Open PowerShell
  • Show Assembly Details
  • Create Code Contract
  • Cancel Build when first project fails
  • Debug Output - custom formatting
  • Build Output - custom formatting
  • Search Output - custom formatting
  • Configure WPF Rendering
  • Configure Fusion Logs
  • Configure IE for debugging
  • Locate Source File
  • Thumbnails in IDE Navigator
  • Extended support for xaml, aspx, css, js and html files
  • Disable Ctrl + Mouse Wheel Zoom
  • Zoom to Mouse Pointer
  • Configurability
  • Attach to local IIS
  • Copy Full Path
  • Build Startup Projects
  • Open Command Prompt
  • Search Online
  • Build Statistics
  • Group linked items
  • Copy/Paste Reference
  • Copy/Paste as Link
  • Collapse Solution
  • Group items directly from user interface (DependantUpon)
  • Open In Expression Blend
  • Locate in Solution
  • Edit Project File
  • Edit Solution File
  • Show All Files

and others, so try it now!

How to read a line from a text file in c/c++?

In c, you could use fopen, and getch. Usually, if you can't be exactly sure of the length of the longest line, you could allocate a large buffer (e.g. 8kb) and almost be guaranteed of getting all lines.

If there's a chance you may have really really long lines and you have to process line by line, you could malloc a resonable buffer, and use realloc to double it's size each time you get close to filling it.

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

void handle_line(char *line) {
  printf("%s", line);
}

int main(int argc, char *argv[]) {
    int size = 1024, pos;
    int c;
    char *buffer = (char *)malloc(size);

    FILE *f = fopen("myfile.txt", "r");
    if(f) {
      do { // read all lines in file
        pos = 0;
        do{ // read one line
          c = fgetc(f);
          if(c != EOF) buffer[pos++] = (char)c;
          if(pos >= size - 1) { // increase buffer length - leave room for 0
            size *=2;
            buffer = (char*)realloc(buffer, size);
          }
        }while(c != EOF && c != '\n');
        buffer[pos] = 0;
        // line is now in buffer
        handle_line(buffer);
      } while(c != EOF); 
      fclose(f);           
    }
    free(buffer);
    return 0;
}

How to select a column name with a space in MySQL

To each his own but the right way to code this is to rename the columns inserting underscore so there are no gaps. This will ensure zero errors when coding. When printing the column names for public display you could search-and-replace to replace the underscore with a space.

git: fatal unable to auto-detect email address

For Visual Studio users:

  1. Open Visual Studio
  2. Click on Git menu > Source Control > Git Repository Settings > General
  3. Set the 'User name' and 'Email'
  4. Click 'OK'

How to link a folder with an existing Heroku app

Heroku links your projects based on the heroku git remote (and a few other options, see the update below). To add your Heroku remote as a remote in your current repository, use the following command:

git remote add heroku [email protected]:project.git

where project is the name of your Heroku project (the same as the project.heroku.com subdomain). Once you've done so, you can use the heroku xxxx commands (assuming you have the Heroku Toolbelt installed), and can push to Heroku as usual via git push heroku master. As a shortcut, if you're using the command line tool, you can type:

heroku git:remote -a project

where, again, project is the name of your Heroku project (thanks, Colonel Panic). You can name the Git remote anything you want by passing -r remote_name.

[Update]

As mentioned by Ben in the comments, the remote doesn't need to be named heroku for the gem commands to work. I checked the source, and it appears it works like this:

  1. If you specify an app name via the --app option (e.g. heroku info --app myapp), it will use that app.
  2. If you specify a Git remote name via the --remote option (e.g. heroku info --remote production), it will use the app associated with that Git remote.
  3. If you specify no option and you have heroku.remote set in your Git config file, it will use the app associated with that remote (for example, to set the default remote to "production" use git config heroku.remote production in your repository, and Heroku will run git config heroku.remote to read the value of this setting)
  4. If you specify no option, the gem finds no configuration in your .git/config file, and the gem only finds one remote in your Git remotes that has "heroku.com" in the URL, it will use that remote.
  5. If none of these work, it raises an error instructing you to pass --app to your command.

Why do I get PLS-00302: component must be declared when it exists?

I came here because I had the same problem.
What was the problem for me was that the procedure was defined in the package body, but not in the package header.
I was executing my function with a lose BEGIN END statement.

How to convert a timezone aware string to datetime in Python without dateutil?

You can convert like this.

date = datetime.datetime.strptime('2019-3-16T5-49-52-595Z','%Y-%m-%dT%H-%M-%S-%f%z')
date_time = date.strftime('%Y-%m-%dT%H:%M:%S.%fZ')

1052: Column 'id' in field list is ambiguous

SQL supports qualifying a column by prefixing the reference with either the full table name:

SELECT tbl_names.id, tbl_section.id, name, section
  FROM tbl_names
  JOIN tbl_section ON tbl_section.id = tbl_names.id 

...or a table alias:

SELECT n.id, s.id, n.name, s.section
  FROM tbl_names n
  JOIN tbl_section s ON s.id = n.id 

The table alias is the recommended approach -- why type more than you have to?

Why Do These Queries Look Different?

Secondly, my answers use ANSI-92 JOIN syntax (yours is ANSI-89). While they perform the same, ANSI-89 syntax does not support OUTER joins (RIGHT, LEFT, FULL). ANSI-89 syntax should be considered deprecated, there are many on SO who will not vote for ANSI-89 syntax to reinforce that. For more information, see this question.

How to save an activity state using save instance state?

Kotlin Solution: For custom class save in onSaveInstanceState you can be converted your class to JSON string and restore it with Gson convertion and for single String, Double, Int, Long value save and restore as following. The following example is for Fragment and Activity:

For Activity:

For put data in saveInstanceState:

override fun onSaveInstanceState(outState: Bundle) {
        super.onSaveInstanceState(outState)

        //for custom class-----
        val gson = Gson()
        val json = gson.toJson(your_custom_class)
        outState.putString("CUSTOM_CLASS", json)

        //for single value------
        outState.putString("MyString", stringValue)
        outState.putBoolean("MyBoolean", true)
        outState.putDouble("myDouble", doubleValue)
        outState.putInt("MyInt", intValue)
    }

Restore data:

 override fun onRestoreInstanceState(savedInstanceState: Bundle) {
    super.onRestoreInstanceState(savedInstanceState)

    //for custom class restore
    val json = savedInstanceState?.getString("CUSTOM_CLASS")
    if (!json!!.isEmpty()) {
        val gson = Gson()
        testBundle = gson.fromJson(json, Session::class.java)
    }

  //for single value restore

   val myBoolean: Boolean = savedInstanceState?.getBoolean("MyBoolean")
   val myDouble: Double = savedInstanceState?.getDouble("myDouble")
   val myInt: Int = savedInstanceState?.getInt("MyInt")
   val myString: String = savedInstanceState?.getString("MyString")
 }

You can restore it on Activity onCreate also.

For fragment:

For put class in saveInstanceState:

 override fun onSaveInstanceState(outState: Bundle) {
        super.onSaveInstanceState(outState)
        val gson = Gson()
        val json = gson.toJson(customClass)
        outState.putString("CUSTOM_CLASS", json)
    }

Restore data:

 override fun onActivityCreated(savedInstanceState: Bundle?) {
        super.onActivityCreated(savedInstanceState)

        //for custom class restore
        if (savedInstanceState != null) {
            val json = savedInstanceState.getString("CUSTOM_CLASS")
            if (!json!!.isEmpty()) {
                val gson = Gson()
                val customClass: CustomClass = gson.fromJson(json, CustomClass::class.java)
            }
        }

      // for single value restore
      val myBoolean: Boolean = savedInstanceState.getBoolean("MyBoolean")
      val myDouble: Double = savedInstanceState.getDouble("myDouble")
      val myInt: Int = savedInstanceState.getInt("MyInt")
      val myString: String = savedInstanceState.getString("MyString")
    }

SSRS the definition of the report is invalid

I just received this obscure message when trying to deploy a report from BIDS.

After a little hunting I found a more descriptive error by going into the Preview window.

How to get address location from latitude and longitude in Google Map.?

Simply pass latitude, longitude and your Google API Key to the following query string, you will get a json array, fetch your city from there.

https://maps.googleapis.com/maps/api/geocode/json?latlng=44.4647452,7.3553838&key=YOUR_API_KEY

Note: Ensure that no space exists between the latitude and longitude values when passed in the latlng parameter.

Click here to get an API key

How can I find the current OS in Python?

If you want user readable data but still detailed, you can use platform.platform()

>>> import platform
>>> platform.platform()
'Linux-3.3.0-8.fc16.x86_64-x86_64-with-fedora-16-Verne'

platform also has some other useful methods:

>>> platform.system()
'Windows'
>>> platform.release()
'XP'
>>> platform.version()
'5.1.2600'

Here's a few different possible calls you can make to identify where you are

import platform
import sys

def linux_distribution():
  try:
    return platform.linux_distribution()
  except:
    return "N/A"

print("""Python version: %s
dist: %s
linux_distribution: %s
system: %s
machine: %s
platform: %s
uname: %s
version: %s
mac_ver: %s
""" % (
sys.version.split('\n'),
str(platform.dist()),
linux_distribution(),
platform.system(),
platform.machine(),
platform.platform(),
platform.uname(),
platform.version(),
platform.mac_ver(),
))

The outputs of this script ran on a few different systems (Linux, Windows, Solaris, MacOS) and architectures (x86, x64, Itanium, power pc, sparc) is available here: https://github.com/hpcugent/easybuild/wiki/OS_flavor_name_version

e.g. Solaris on sparc gave:

Python version: ['2.6.4 (r264:75706, Aug  4 2010, 16:53:32) [C]']
dist: ('', '', '')
linux_distribution: ('', '', '')
system: SunOS
machine: sun4u
platform: SunOS-5.9-sun4u-sparc-32bit-ELF
uname: ('SunOS', 'xxx', '5.9', 'Generic_122300-60', 'sun4u', 'sparc')
version: Generic_122300-60
mac_ver: ('', ('', '', ''), '')

Turn off enclosing <p> tags in CKEditor 3.0

MAKE THIS YOUR config.js file code

CKEDITOR.editorConfig = function( config ) {

   //   config.enterMode = 2; //disabled <p> completely
        config.enterMode = CKEDITOR.ENTER_BR // pressing the ENTER KEY input <br/>
        config.shiftEnterMode = CKEDITOR.ENTER_P; //pressing the SHIFT + ENTER KEYS input <p>
        config.autoParagraph = false; // stops automatic insertion of <p> on focus
    };

Ruby optional parameters

It isn't possible to do it the way you've defined ldap_get. However, if you define ldap_get like this:

def ldap_get ( base_dn, filter, attrs=nil, scope=LDAP::LDAP_SCOPE_SUBTREE )

Now you can:

ldap_get( base_dn, filter, X )

But now you have problem that you can't call it with the first two args and the last arg (the same problem as before but now the last arg is different).

The rationale for this is simple: Every argument in Ruby isn't required to have a default value, so you can't call it the way you've specified. In your case, for example, the first two arguments don't have default values.

"Javac" doesn't work correctly on Windows 10

I added below Path in environment variable

;%JAVA_HOME%/bin instead of %JAVA_HOME%\bin

in my case , it fix the problem

Get value of a merged cell of an excel from its cell address in vba

Even if it is really discouraged to use merge cells in Excel (use Center Across Selection for instance if needed), the cell that "contains" the value is the one on the top left (at least, that's a way to express it).

Hence, you can get the value of merged cells in range B4:B11 in several ways:

  • Range("B4").Value
  • Range("B4:B11").Cells(1).Value
  • Range("B4:B11").Cells(1,1).Value

You can also note that all the other cells have no value in them. While debugging, you can see that the value is empty.

Also note that Range("B4:B11").Value won't work (raises an execution error number 13 if you try to Debug.Print it) because it returns an array.

How do I schedule a task to run at periodic intervals?

Use timer.scheduleAtFixedRate

public void scheduleAtFixedRate(TimerTask task,
                                long delay,
                                long period)

Schedules the specified task for repeated fixed-rate execution, beginning after the specified delay. Subsequent executions take place at approximately regular intervals, separated by the specified period.
In fixed-rate execution, each execution is scheduled relative to the scheduled execution time of the initial execution. If an execution is delayed for any reason (such as garbage collection or other background activity), two or more executions will occur in rapid succession to "catch up." In the long run, the frequency of execution will be exactly the reciprocal of the specified period (assuming the system clock underlying Object.wait(long) is accurate).

Fixed-rate execution is appropriate for recurring activities that are sensitive to absolute time, such as ringing a chime every hour on the hour, or running scheduled maintenance every day at a particular time. It is also appropriate for recurring activities where the total time to perform a fixed number of executions is important, such as a countdown timer that ticks once every second for ten seconds. Finally, fixed-rate execution is appropriate for scheduling multiple repeating timer tasks that must remain synchronized with respect to one another.

Parameters:

  • task - task to be scheduled.
  • delay - delay in milliseconds before task is to be executed.
  • period - time in milliseconds between successive task executions.

Throws:

  • IllegalArgumentException - if delay is negative, or delay + System.currentTimeMillis() is negative.
  • IllegalStateException - if task was already scheduled or cancelled, timer was cancelled, or timer thread terminated.

Mail multipart/alternative vs multipart/mixed

Use multipart/mixed with the first part as multipart/alternative and subsequent parts for the attachments. In turn, use text/plain and text/html parts within the multipart/alternative part.

A capable email client should then recognise the multipart/alternative part and display the text part or html part as necessary. It should also show all of the subsequent parts as attachment parts.

The important thing to note here is that, in multipart MIME messages, it is perfectly valid to have parts within parts. In theory, that nesting can extend to any depth. Any reasonably capable email client should then be able to recursively process all of the message parts.

Delete last commit in bitbucket

By now, cloud bitbucket (I'm not sure which version) allows to revert a commit from the file system as follows (I do not see how to revert from the Bitbucket interface in the Chrome browser).

-backup your entire directory to secure the changes you inadvertently committed

-select checked out directory

-right mouse button: tortoise git menu

-repo-browser (the menu option 'revert' only undoes the uncommited changes)

-press the HEAD button

-select the uppermost line (the last commit)

-right mouse button: revert change by this commit

-after it undid the changes on the file system, press commit

-this updates GIT with a message 'Revert (your previous message). This reverts commit so-and-so'

-select 'commit and push'.

Getting the client's time zone (and offset) in JavaScript

See this resultant operator was opposite to the Timezone .So apply some math function then validate the num less or more.

enter image description here

See the MDN document

_x000D_
_x000D_
var a = new Date().getTimezoneOffset();_x000D_
_x000D_
var res = -Math.round(a/60)+':'+-(a%60);_x000D_
res = res < 0 ?res : '+'+res;_x000D_
_x000D_
console.log(res)
_x000D_
_x000D_
_x000D_

Vim: insert the same characters across multiple lines

Suppose you have this file:

something

name
comment
phone
email

something else
and more ...

You want to add "vendor_" in front of "name", "comment", "phone", and "email", regardless of where they appear in the file.

:%s/\<\(name\|comment\|phone\|email\)\>/vendor_\1/gc

The c flag will prompt you for confirmation. You can drop that if you don't want the prompt.

How to read until EOF from cin in C++

Probable simplest and generally efficient:

#include <iostream>
int main()
{
    std::cout << std::cin.rdbuf();
}

If needed, use stream of other types like std::ostringstream as buffer instead of standard output stream here.

Pandas - Get first row value of a given column

To select the ith row, use iloc:

In [31]: df_test.iloc[0]
Out[31]: 
ATime     1.2
X         2.0
Y        15.0
Z         2.0
Btime     1.2
C        12.0
D        25.0
E        12.0
Name: 0, dtype: float64

To select the ith value in the Btime column you could use:

In [30]: df_test['Btime'].iloc[0]
Out[30]: 1.2

There is a difference between df_test['Btime'].iloc[0] (recommended) and df_test.iloc[0]['Btime']:

DataFrames store data in column-based blocks (where each block has a single dtype). If you select by column first, a view can be returned (which is quicker than returning a copy) and the original dtype is preserved. In contrast, if you select by row first, and if the DataFrame has columns of different dtypes, then Pandas copies the data into a new Series of object dtype. So selecting columns is a bit faster than selecting rows. Thus, although df_test.iloc[0]['Btime'] works, df_test['Btime'].iloc[0] is a little bit more efficient.

There is a big difference between the two when it comes to assignment. df_test['Btime'].iloc[0] = x affects df_test, but df_test.iloc[0]['Btime'] may not. See below for an explanation of why. Because a subtle difference in the order of indexing makes a big difference in behavior, it is better to use single indexing assignment:

df.iloc[0, df.columns.get_loc('Btime')] = x

df.iloc[0, df.columns.get_loc('Btime')] = x (recommended):

The recommended way to assign new values to a DataFrame is to avoid chained indexing, and instead use the method shown by andrew,

df.loc[df.index[n], 'Btime'] = x

or

df.iloc[n, df.columns.get_loc('Btime')] = x

The latter method is a bit faster, because df.loc has to convert the row and column labels to positional indices, so there is a little less conversion necessary if you use df.iloc instead.


df['Btime'].iloc[0] = x works, but is not recommended:

Although this works, it is taking advantage of the way DataFrames are currently implemented. There is no guarantee that Pandas has to work this way in the future. In particular, it is taking advantage of the fact that (currently) df['Btime'] always returns a view (not a copy) so df['Btime'].iloc[n] = x can be used to assign a new value at the nth location of the Btime column of df.

Since Pandas makes no explicit guarantees about when indexers return a view versus a copy, assignments that use chained indexing generally always raise a SettingWithCopyWarning even though in this case the assignment succeeds in modifying df:

In [22]: df = pd.DataFrame({'foo':list('ABC')}, index=[0,2,1])
In [24]: df['bar'] = 100
In [25]: df['bar'].iloc[0] = 99
/home/unutbu/data/binky/bin/ipython:1: SettingWithCopyWarning: 
A value is trying to be set on a copy of a slice from a DataFrame

See the caveats in the documentation: http://pandas.pydata.org/pandas-docs/stable/indexing.html#indexing-view-versus-copy
  self._setitem_with_indexer(indexer, value)

In [26]: df
Out[26]: 
  foo  bar
0   A   99  <-- assignment succeeded
2   B  100
1   C  100

df.iloc[0]['Btime'] = x does not work:

In contrast, assignment with df.iloc[0]['bar'] = 123 does not work because df.iloc[0] is returning a copy:

In [66]: df.iloc[0]['bar'] = 123
/home/unutbu/data/binky/bin/ipython:1: SettingWithCopyWarning: 
A value is trying to be set on a copy of a slice from a DataFrame

See the caveats in the documentation: http://pandas.pydata.org/pandas-docs/stable/indexing.html#indexing-view-versus-copy

In [67]: df
Out[67]: 
  foo  bar
0   A   99  <-- assignment failed
2   B  100
1   C  100

Warning: I had previously suggested df_test.ix[i, 'Btime']. But this is not guaranteed to give you the ith value since ix tries to index by label before trying to index by position. So if the DataFrame has an integer index which is not in sorted order starting at 0, then using ix[i] will return the row labeled i rather than the ith row. For example,

In [1]: df = pd.DataFrame({'foo':list('ABC')}, index=[0,2,1])

In [2]: df
Out[2]: 
  foo
0   A
2   B
1   C

In [4]: df.ix[1, 'foo']
Out[4]: 'C'

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

sha1sum is quite a bit faster on Power9 than md5sum

$ uname -mov
#1 SMP Mon May 13 12:16:08 EDT 2019 ppc64le GNU/Linux

$ cat /proc/cpuinfo
processor       : 0
cpu             : POWER9, altivec supported
clock           : 2166.000000MHz
revision        : 2.2 (pvr 004e 1202)

$ ls -l linux-master.tar
-rw-rw-r-- 1 x x 829685760 Jan 29 14:30 linux-master.tar

$ time sha1sum linux-master.tar
10fbf911e254c4fe8e5eb2e605c6c02d29a88563  linux-master.tar

real    0m1.685s
user    0m1.528s
sys     0m0.156s

$ time md5sum linux-master.tar
d476375abacda064ae437a683c537ec4  linux-master.tar

real    0m2.942s
user    0m2.806s
sys     0m0.136s

$ time sum linux-master.tar
36928 810240

real    0m2.186s
user    0m1.917s
sys     0m0.268s

How to merge remote changes at GitHub?

If you "git pull" and it says "Already up-to-date.", and still get this error, it might be because one of your other branches isn't up to date. Try switching to another branch and making sure that one is also up-to-date before trying to "git push" again:

Switch to branch "foo" and update it:

$ git checkout foo
$ git pull

You can see the branches you've got by issuing command:

$ git branch

Center align a column in twitter bootstrap

The question is correctly answered here Center a column using Twitter Bootstrap 3

For odd rows: i.e., col-md-7 or col-large-9 use this

Add col-centered to the column you want centered.

<div class="col-lg-11 col-centered">    

And add this to your stylesheet:

.col-centered{
float: none;
margin: 0 auto;
}

For even rows: i.e., col-md-6 or col-large-10 use this

Simply use bootstrap 3's offset col class. i.e.,

<div class="col-lg-10 col-lg-offset-1">

How to fix 'android.os.NetworkOnMainThreadException'?

As Android is working on a single thread, you should not do any network operation on the main thread. There are various ways to avoid this.

Use the following way to perform a network operation

  • Asysnctask: For small operations which don't take much time.
  • Intent Service: For network operation which take a big amount of time.
  • Use a custom library like Volley and Retrofit for handling complex network operations

Never use StrictMode.setThreadPolicy(policy), as it will freeze your UI and is not at all a good idea.

Exception: "URI formats are not supported"

     string ImagePath = "";

        HttpWebRequest request = (HttpWebRequest)WebRequest.Create(ImagePath);
        string a = "";
        try
        {
            HttpWebResponse response = (HttpWebResponse)request.GetResponse(); 
            Stream receiveStream = response.GetResponseStream();
            if (receiveStream.CanRead)
            { a = "OK"; }
        }

        catch { }

How to check if a string contains a specific text

http://php.net/manual/en/function.strpos.php I think you are wondiner if 'some text' exists in the string right?

if(strpos( $a , 'some text' ) !== false)

How to round an image with Glide library?

Here is a more modular and cleaner way to circle crop your bitmap in Glide:

  1. Create a custom transformation by extending BitmapTransformation then override transform method like this :

For Glide 4.x.x

public class CircularTransformation extends BitmapTransformation {

@Override
protected Bitmap transform(BitmapPool pool, Bitmap toTransform, int outWidth, int outHeight) {
    RoundedBitmapDrawable circularBitmapDrawable =
            RoundedBitmapDrawableFactory.create(null, toTransform);
    circularBitmapDrawable.setCircular(true);
    Bitmap bitmap = pool.get(outWidth, outHeight, Bitmap.Config.ARGB_8888);
    Canvas canvas = new Canvas(bitmap);
    circularBitmapDrawable.setBounds(0, 0, outWidth, outHeight);
    circularBitmapDrawable.draw(canvas);
    return bitmap;
    }

@Override
public void updateDiskCacheKey(MessageDigest messageDigest) {}

}

For Glide 3.x.x

public class CircularTransformation extends BitmapTransformation {

@Override
protected Bitmap transform(BitmapPool pool, Bitmap toTransform, int outWidth, int outHeight) {
    RoundedBitmapDrawable circularBitmapDrawable =
            RoundedBitmapDrawableFactory.create(null, toTransform);
    circularBitmapDrawable.setCircular(true);
    Bitmap bitmap = pool.get(outWidth, outHeight, Bitmap.Config.ARGB_8888);
    Canvas canvas = new Canvas(bitmap);
    circularBitmapDrawable.setBounds(0, 0, outWidth, outHeight);
    circularBitmapDrawable.draw(canvas);
    return bitmap;
    }

@Override
public String getId() {
    // Return some id that uniquely identifies your transformation.
    return "CircularTransformation";
    }

}
  1. Then set it in Glide builder where you need it:
Glide.with(yourActivity)
   .load(yourUrl)
   .asBitmap()
   .transform(new CircularTransformation())
   .into(yourView);

Hope this helps :)

Detecting when user scrolls to bottom of div with jQuery

$(window).on("scroll", function() {
    //get height of the (browser) window aka viewport
    var scrollHeight = $(document).height();
    // get height of the document 
    var scrollPosition = $(window).height() + $(window).scrollTop();
    if ((scrollHeight - scrollPosition) / scrollHeight === 0) {
        // code to run when scroll to bottom of the page
    }
});

This is the code on github.

Java string to date conversion

String str_date = "11-June-07";
DateFormat formatter;
Date date;
formatter = new SimpleDateFormat("dd-MMM-yy");
date = formatter.parse(str_date);

Restore DB — Error RESTORE HEADERONLY is terminating abnormally.

You can check out this blog post. It had solved my problem.

http://dotnetguts.blogspot.com/2010/06/restore-failed-for-server-restore.html

Select @@Version
It had given me following output Microsoft SQL Server 2005 - 9.00.4053.00 (Intel X86) May 26 2009 14:24:20 Copyright (c) 1988-2005 Microsoft Corporation Express Edition on Windows NT 6.0 (Build 6002: Service Pack 2)

You will need to re-install to a new named instance to ensure that you are using the new SQL Server version.

What values for checked and selected are false?

There are no values that will cause the checkbox to be unchecked. If the checked attribute exists, the checkbox will be checked regardless of what value you set it to.

_x000D_
_x000D_
<input type="checkbox" checked />_x000D_
<input type="checkbox" checked="" />_x000D_
<input type="checkbox" checked="checked" />_x000D_
<input type="checkbox" checked="unchecked" />_x000D_
<input type="checkbox" checked="true" />_x000D_
<input type="checkbox" checked="false" />_x000D_
<input type="checkbox" checked="on" />_x000D_
<input type="checkbox" checked="off" />_x000D_
<input type="checkbox" checked="1" />_x000D_
<input type="checkbox" checked="0" />_x000D_
<input type="checkbox" checked="yes" />_x000D_
<input type="checkbox" checked="no" />_x000D_
<input type="checkbox" checked="y" />_x000D_
<input type="checkbox" checked="n" />
_x000D_
_x000D_
_x000D_

Renders everything checked in all modern browsers (FF3.6, Chrome 10, IE8).

How to replace plain URLs with links?

Made some optimizations to Travis' Linkify() code above. I also fixed a bug where email addresses with subdomain type formats would not be matched (i.e. [email protected]).

In addition, I changed the implementation to prototype the String class so that items can be matched like so:

var text = '[email protected]';
text.linkify();

'http://stackoverflow.com/'.linkify();

Anyway, here's the script:

if(!String.linkify) {
    String.prototype.linkify = function() {

        // http://, https://, ftp://
        var urlPattern = /\b(?:https?|ftp):\/\/[a-z0-9-+&@#\/%?=~_|!:,.;]*[a-z0-9-+&@#\/%=~_|]/gim;

        // www. sans http:// or https://
        var pseudoUrlPattern = /(^|[^\/])(www\.[\S]+(\b|$))/gim;

        // Email addresses
        var emailAddressPattern = /[\w.]+@[a-zA-Z_-]+?(?:\.[a-zA-Z]{2,6})+/gim;

        return this
            .replace(urlPattern, '<a href="$&">$&</a>')
            .replace(pseudoUrlPattern, '$1<a href="http://$2">$2</a>')
            .replace(emailAddressPattern, '<a href="mailto:$&">$&</a>');
    };
}

jQuery equivalent to Prototype array.last()

Why not just use simple javascript?

var array=[1,2,3,4];
var lastEl = array[array.length-1];

You can write it as a method too, if you like (assuming prototype has not been included on your page):

Array.prototype.last = function() {return this[this.length-1];}

To get specific part of a string in c#

If you want to get the strings separated by the , you can use

string b = a.Split(',')[0];

mysql server port number

This is a PDO-only visualization, as the mysql_* library is deprecated.

<?php
    // Begin Vault (this is in a vault, not actually hard-coded)
    $host="hostname";
    $username="GuySmiley";
    $password="thePassword";
    $dbname="dbname";
    $port="3306";
    // End Vault

    try {
        $dbh = new PDO("mysql:host=$host;port=$port;dbname=$dbname;charset=utf8", $username, $password);
        $dbh->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
        echo "I am connected.<br/>";

        // ... continue with your code

        // PDO closes connection at end of script
    } catch (PDOException $e) {
        echo 'PDO Exception: ' . $e->getMessage();
        exit();
    }
?>

Note that this OP Question appeared not to be about port numbers afterall. If you are using the default port of 3306 always, then consider removing it from the uri, that is, remove the port=$port; part.

If you often change ports, consider the above port usage for more maintainability having changes made to the $port variable.

Some likely errors returned from above:

PDO Exception: SQLSTATE[HY000] [2002] No connection could be made because the target machine actively refused it.
PDO Exception: SQLSTATE[HY000] [2002] php_network_getaddresses: getaddrinfo failed: No such host is known.

In the below error, we are at least getting closer, after changing our connect information:

PDO Exception: SQLSTATE[HY000] [1045] Access denied for user 'GuySmiley'@'localhost' (using password: YES)

After further changes, we are really close now, but not quite:

PDO Exception: SQLSTATE[HY000] [1049] Unknown database 'mustard'

From the Manual on PDO Connections:

Node package ( Grunt ) installed but not available

On Windows 10 Add this to your Path:

%APPDATA%\npm

This references the folder ~/AppData/Roaming/npm

[Assumes that you have already run npm install -g grunt-cli]

How do I define the name of image built with docker-compose

According to 3.9 version of Docker compose, you can use image: myapp:tag to specify name and tag.

version: "3.9"
services:
  webapp:
    build:
      context: .
      dockerfile: Dockerfile
    image: webapp:tag

Reference: https://docs.docker.com/compose/compose-file/compose-file-v3/

json.decoder.JSONDecodeError: Extra data: line 2 column 1 (char 190)

I was parsing JSON from a REST API call and got this error. It turns out the API had become "fussier" (eg about order of parameters etc) and so was returning malformed results. Check that you are getting what you expect :)

How to use onClick() or onSelect() on option tag in a JSP page?

The answer you gave above works but it is confusing because you have used two names twice and you have an unnecessary line of code. you are doing a process that is not necessary.

it's a good idea when debugging code to get pen and paper and draw little boxes to represent memory spaces (i.e variables being stored) and then to draw arrows to indicate when a variable goes into a little box and when it comes out, if it gets overwritten or is a copy made etc.

if you do this with the code below you will see that

var selectBox = document.getElementById("selectBox");

gets put in a box and stays there you don't do anything with it afterwards.

and

var selectBox = document.getElementById("selectBox");

is hard to debug and is confusing when you have a select id of selectBox for the options list . ---- which selectBox do you want to manipulate / query / etc is it the local var selectBox that will disappear or is it the selectBox id you have assigned to the select tag

your code works until you add to it or modify it then you can easily loose track and get all mixed up

<html>
<head>
<script type="text/javascript">

function changeFunc() {
var selectBox = document.getElementById("selectBox");
var selectedValue = selectBox.options[selectBox.selectedIndex].value;
alert(selectedValue);
}

</script>
</head>

<body>
<select id="selectBox" onchange="changeFunc();">
<option value="1">Option #1</option>
<option value="2">Option #2</option>
</select>
</body>
</html>

a leaner way that works also is:

<html>
<head>
<script type="text/javascript">

function changeFunc() {

var selectedValue = selectBox.options[selectBox.selectedIndex].value;
alert(selectedValue);
}

</script>
</head>
<body>
<select id="selectBox" onchange="changeFunc();">
<option value="1">Option #1</option>
<option value="2">Option #2</option>
</select>
</body>
</html>

and it's a good idea to use descriptive names that match the program and task you are working on am currently writing a similar program to accept and process postcodes using your code and modifying it with descriptive names the object is to make computer language as close to natural language as possible.

<script type="text/javascript">

function Mapit(){

var actualPostcode=getPostcodes.options[getPostcodes.selectedIndex].value;

alert(actualPostcode);

// alert is for debugging only next we go on to process and do something
// in this developing program it will placing markers on a map

}

</script>

<select id="getPostcodes" onchange="Mapit();">

<option>London North Inner</option>

<option>N1</option>

<option>London North Outer</option>

<option>N2</option>
<option>N3</option>
<option>N4</option>

// a lot more options follow 
// with text in options to divide into areas and nothing will happen 
// if visitor clicks on the text function Mapit() will ignore
// all clicks on the divider text inserted into option boxes

</select>

How to use shell commands in Makefile

Also, in addition to torek's answer: one thing that stands out is that you're using a lazily-evaluated macro assignment.

If you're on GNU Make, use the := assignment instead of =. This assignment causes the right hand side to be expanded immediately, and stored in the left hand variable.

FILES := $(shell ...)  # expand now; FILES is now the result of $(shell ...)

FILES = $(shell ...)   # expand later: FILES holds the syntax $(shell ...)

If you use the = assignment, it means that every single occurrence of $(FILES) will be expanding the $(shell ...) syntax and thus invoking the shell command. This will make your make job run slower, or even have some surprising consequences.

Trim a string in C

void inPlaceStrTrim(char* str) {
    int k = 0;
    int i = 0;
    for (i=0; str[i] != '\0';) {
        if (isspace(str[i])) {
            // we have got a space...
            k = i;
            for (int j=i; j<strlen(str)-1; j++) {
                str[j] = str[j+1];
            }
            str[strlen(str)-1] = '\0';
            i = k; // start the loop again where we ended..
        } else {
            i++;
        }
    }
}

What would be the Unicode character for big bullet in the middle of the character?

http://www.unicode.org is the place to look for symbol names.

? BLACK CIRCLE        25CF
? MEDIUM BLACK CIRCLE 26AB
? BLACK LARGE CIRCLE  2B24

or even:

 NEW MOON SYMBOL   1F311

Good luck finding a font that supports them all. Only one shows up in Windows 7 with Chrome.

VBA to copy a file from one directory to another

This method is even easier if you're ok with fewer options:

FileCopy source, destination

How do I set hostname in docker-compose?

This issue is still open here: https://github.com/docker/compose/issues/2925

You can set hostname but it is not reachable from other containers. So it is mostly useless.

Short rot13 function - Python

I couldn't leave this question here with out a single statement using the modulo operator.

def rot13(s):
    return ''.join([chr(x.islower() and ((ord(x) - 84) % 26) + 97
                        or x.isupper() and ((ord(x) - 52) % 26) + 65
                        or ord(x))
                    for x in s])

This is not pythonic nor good practice, but it works!

>> rot13("Hello World!")
Uryyb Jbeyq!

What is the correct way to restore a deleted file from SVN?

Use svn merge:

svn merge -c -[rev num that deleted the file] http://<path to repository>

So an example:

svn merge -c -12345 https://svn.mysite.com/svn/repo/project/trunk
             ^ The negative is important

For TortoiseSVN (I think...)

  • Right click in Explorer, go to TortoiseSVN -> Merge...
  • Make sure "Merge a range of revisions" is selected, click Next
  • In the "Revision range to merge" textbox, specify the revision that removed the file
  • Check the "Reverse merge" checkbox, click Next
  • Click Merge

That is completely untested, however.


Edited by OP: This works on my version of TortoiseSVN (the old kind without the next button)

  • Go to the folder that stuff was delated from
  • Right click in Explorer, go to TortoiseSVN -> Merge...
  • in the From section enter the revision that did the delete
  • in the To section enter the revision before the delete.
  • Click "merge"
  • commit

The trick is to merge backwards. Kudos to sean.bright for pointing me in the right direction!


Edit: We are using different versions. The method I described worked perfectly with my version of TortoiseSVN.

Also of note is that if there were multiple changes in the commit you are reverse merging, you'll want to revert those other changes once the merge is done before you commit. If you don't, those extra changes will also be reversed.

Jquery: Find Text and replace

Try This

$("#id1 p:contains('dogsss')").replaceWith("dollsss");

When should an Excel VBA variable be killed or set to Nothing?

VBA uses a garbage collector which is implemented by reference counting.

There can be multiple references to a given object (for example, Dim aw = ActiveWorkbook creates a new reference to Active Workbook), so the garbage collector only cleans up an object when it is clear that there are no other references. Setting to Nothing is an explicit way of decrementing the reference count. The count is implicitly decremented when you exit scope.

Strictly speaking, in modern Excel versions (2010+) setting to Nothing isn't necessary, but there were issues with older versions of Excel (for which the workaround was to explicitly set)

javascript clear field value input

Here is one solution with jQuery for browsers that don't support the placeholder attribute.

$('[placeholder]').focus(function() {
  var input = $(this);

  if (input.val() == input.attr('placeholder')) {
    input.val('');
    input.removeClass('placeholder');
  }
}).blur(function() {
  var input = $(this);

  if (input.val() == '' || input.val() == input.attr('placeholder')) {
    input.addClass('placeholder');
    input.val(input.attr('placeholder'));
  }
}).blur();

Found here: http://www.hagenburger.net/BLOG/HTML5-Input-Placeholder-Fix-With-jQuery.html

Get table names using SELECT statement in MySQL

Besides using the INFORMATION_SCHEMA table, to use SHOW TABLES to insert into a table you would use the following

<?php
 $sql = "SHOW TABLES FROM $dbname";
 $result = mysql_query($sql);
 $arrayCount = 0
 while ($row = mysql_fetch_row($result)) {
  $tableNames[$arrayCount] = $row[0];
  $arrayCount++; //only do this to make sure it starts at index 0
 }
 foreach ($tableNames as &$name {
  $query = "INSERT INTO metadata (table_name) VALUES ('".$name."')";
  mysql_query($query);
 }
?>

How to set div width using ng-style

ngStyle accepts a map:

$scope.myStyle = {
    "width" : "900px",
    "background" : "red"
};

Fiddle

How to determine the current language of a wordpress page when using polylang?

We can use the get_locale function:

if (get_locale() == 'en_GB') {
    // drink tea
}

Find index of a value in an array

For arrays you can use: Array.FindIndex<T>:

int keyIndex = Array.FindIndex(words, w => w.IsKey);

For lists you can use List<T>.FindIndex:

int keyIndex = words.FindIndex(w => w.IsKey);

You can also write a generic extension method that works for any Enumerable<T>:

///<summary>Finds the index of the first item matching an expression in an enumerable.</summary>
///<param name="items">The enumerable to search.</param>
///<param name="predicate">The expression to test the items against.</param>
///<returns>The index of the first matching item, or -1 if no items match.</returns>
public static int FindIndex<T>(this IEnumerable<T> items, Func<T, bool> predicate) {
    if (items == null) throw new ArgumentNullException("items");
    if (predicate == null) throw new ArgumentNullException("predicate");

    int retVal = 0;
    foreach (var item in items) {
        if (predicate(item)) return retVal;
        retVal++;
    }
    return -1;
}

And you can use LINQ as well:

int keyIndex = words
    .Select((v, i) => new {Word = v, Index = i})
    .FirstOrDefault(x => x.Word.IsKey)?.Index ?? -1;

OPTION (RECOMPILE) is Always Faster; Why?

There are times that using OPTION(RECOMPILE) makes sense. In my experience the only time this is a viable option is when you are using dynamic SQL. Before you explore whether this makes sense in your situation I would recommend rebuilding your statistics. This can be done by running the following:

EXEC sp_updatestats

And then recreating your execution plan. This will ensure that when your execution plan is created it will be using the latest information.

Adding OPTION(RECOMPILE) rebuilds the execution plan every time that your query executes. I have never heard that described as creates a new lookup strategy but maybe we are just using different terms for the same thing.

When a stored procedure is created (I suspect you are calling ad-hoc sql from .NET but if you are using a parameterized query then this ends up being a stored proc call) SQL Server attempts to determine the most effective execution plan for this query based on the data in your database and the parameters passed in (parameter sniffing), and then caches this plan. This means that if you create the query where there are 10 records in your database and then execute it when there are 100,000,000 records the cached execution plan may no longer be the most effective.

In summary - I don't see any reason that OPTION(RECOMPILE) would be a benefit here. I suspect you just need to update your statistics and your execution plan. Rebuilding statistics can be an essential part of DBA work depending on your situation. If you are still having problems after updating your stats, I would suggest posting both execution plans.

And to answer your question - yes, I would say it is highly unusual for your best option to be recompiling the execution plan every time you execute the query.

Can linux cat command be used for writing text to file?

The Solution to your problem is :

echo " Some Text Goes Here " > filename.txt

But you can use cat command if you want to redirect the output of a file to some other file or if you want to append the output of a file to another file :

cat filename > newfile -- To redirect output of filename to newfile

cat filename >> newfile -- To append the output of filename to newfile

Single Line Nested For Loops

You might be interested in itertools.product, which returns an iterable yielding tuples of values from all the iterables you pass it. That is, itertools.product(A, B) yields all values of the form (a, b), where the a values come from A and the b values come from B. For example:

import itertools

A = [50, 60, 70]
B = [0.1, 0.2, 0.3, 0.4]

print [a + b for a, b in itertools.product(A, B)]

This prints:

[50.1, 50.2, 50.3, 50.4, 60.1, 60.2, 60.3, 60.4, 70.1, 70.2, 70.3, 70.4]

Notice how the final argument passed to itertools.product is the "inner" one. Generally, itertools.product(a0, a1, ... an) is equal to [(i0, i1, ... in) for in in an for in-1 in an-1 ... for i0 in a0]

Matplotlib-Animation "No MovieWriters Available"

If you are using Ubuntu 14.04 ffmpeg is not available. You can install it by using the instructions directly from https://www.ffmpeg.org/download.html.

In short you will have to:

sudo add-apt-repository ppa:mc3man/trusty-media
sudo apt-get update
sudo apt-get install ffmpeg gstreamer0.10-ffmpeg

If this does not work maybe try using sudo apt-get dist-upgrade but this may broke things in your system.

CSS: Hover one element, effect for multiple elements?

You don't need JavaScript for this.

Some CSS would do it. Here is an example:

_x000D_
_x000D_
<html>_x000D_
  <style type="text/css">_x000D_
    .section { background:#ccc; }_x000D_
    .layer { background:#ddd; }_x000D_
    .section:hover img { border:2px solid #333; }_x000D_
    .section:hover .layer { border:2px solid #F90; }_x000D_
  </style>_x000D_
</head>_x000D_
<body>_x000D_
  <div class="section">_x000D_
    <img src="myImage.jpg" />_x000D_
    <div class="layer">Lorem Ipsum</div>_x000D_
  </div>_x000D_
</body>_x000D_
</html>
_x000D_
_x000D_
_x000D_

How to remove item from list in C#?

Short answer:
Remove (from list results)

results.RemoveAll(r => r.ID == 2); will remove the item with ID 2 in results (in place).

Filter (without removing from original list results):

var filtered = result.Where(f => f.ID != 2); returns all items except the one with ID 2

Detailed answer:

I think .RemoveAll() is very flexible, because you can have a list of item IDs which you want to remove - please regard the following example.

If you have:

class myClass {
    public int ID; public string FirstName; public string LastName;
}

and assigned some values to results as follows:

var results = new List<myClass> {
    new myClass { ID=1, FirstName="Bill", LastName="Smith" },   // results[0]
    new myClass { ID=2, FirstName="John", LastName="Wilson" },  // results[1]
    new myClass { ID=3, FirstName="Doug", LastName="Berg" },    // results[2]
    new myClass { ID=4, FirstName="Bill", LastName="Wilson" }   // results[3]
};

Then you can define a list of IDs to remove:

var removeList = new List<int>() { 2, 3 };

And simply use this to remove them:

results.RemoveAll(r => removeList.Any(a => a==r.ID));

It will remove the items 2 and 3 and keep the items 1 and 4 - as specified by the removeList. Note that this happens in place, so there is no additional assigment required.

Of course, you can also use it on single items like:

results.RemoveAll(r => r.ID==4);

where it will remove Bill with ID 4 in our example.

A last thing to mention is that lists have an indexer, that is, they can also be accessed like a dynamic array, i.e. results[3] will give you the 4th element in the results list (because the first element has the index 0, the 2nd has index 1 etc).

So if you want to remove all entries where the first name is the same as in the 4th element of the results list, you can simply do it this way:

results.RemoveAll(r => results[3].FirstName == r.FirstName);

Note that afterwards, only John and Doug will remain in the list, Bill is removed (the first and last element in the example). Important is that the list will shrink automatically, so it has only 2 elements left - and hence the largest allowed index after executing RemoveAll in this example is 1
(which is results.Count() - 1).

Some Trivia: You can use this knowledge and create a local function

void myRemove()  { var last = results.Count() - 1; 
                   results.RemoveAll(r => results[last].FirstName == r.FirstName); }

What do you think will happen, if you call this function twice? Like

myRemove(); myRemove(); 

The first call will remove Bill at the first and last position, the second call will remove Doug and only John Wilson remains in the list.


DotNetFiddle: Run the demo

Note: Since C# Version 8, you can as well write results[^1] instead of var last = results.Count() - 1; and results[last]:

void myRemove() { results.RemoveAll(r => results[^1].FirstName == r.FirstName); }

So you would not need the local variable last anymore (see indices and ranges. For a list of all the new features in C#, look here).

Sort a list of lists with a custom compare function

Since the OP was asking for using a custom compare function (and this is what led me to this question as well), I want to give a solid answer here:

Generally, you want to use the built-in sorted() function which takes a custom comparator as its parameter. We need to pay attention to the fact that in Python 3 the parameter name and semantics have changed.

How the custom comparator works

When providing a custom comparator, it should generally return an integer/float value that follows the following pattern (as with most other programming languages and frameworks):

  • return a negative value (< 0) when the left item should be sorted before the right item
  • return a positive value (> 0) when the left item should be sorted after the right item
  • return 0 when both the left and the right item have the same weight and should be ordered "equally" without precedence

In the particular case of the OP's question, the following custom compare function can be used:

def compare(item1, item2):
    return fitness(item1) - fitness(item2)

Using the minus operation is a nifty trick because it yields to positive values when the weight of left item1 is bigger than the weight of the right item2. Hence item1 will be sorted after item2.

If you want to reverse the sort order, simply reverse the subtraction: return fitness(item2) - fitness(item1)

Calling sorted() in Python 2

sorted(mylist, cmp=compare)

or:

sorted(mylist, cmp=lambda item1, item2: fitness(item1) - fitness(item2))

Calling sorted() in Python 3

from functools import cmp_to_key
sorted(mylist, key=cmp_to_key(compare))

or:

from functools import cmp_to_key
sorted(mylist, key=cmp_to_key(lambda item1, item2: fitness(item1) - fitness(item2)))

How should I make my VBA code compatible with 64-bit Windows?

This work for me:

#If VBA7 And Win64 Then
    Private Declare PtrSafe Function ShellExecuteA Lib "Shell32.dll" _
        (ByVal hwnd As Long, _
        ByVal lpOperation As String, _
        ByVal lpFile As String, _
       ByVal lpParameters As String, _
        ByVal lpDirectory As String, _
        ByVal nShowCmd As Long) As Long
#Else

    Private Declare Function ShellExecuteA Lib "Shell32.dll" _
        (ByVal hwnd As Long, _
        ByVal lpOperation As String, _
        ByVal lpFile As String, _
        ByVal lpParameters As String, _
        ByVal lpDirectory As String, _
        ByVal nShowCmd As Long) As Long
#End If

Thanks Jon49 for insight.

How do search engines deal with AngularJS applications?

Angular's own website serves simplified content to search engines: http://docs.angularjs.org/?_escaped_fragment_=/tutorial/step_09

Say your Angular app is consuming a Node.js/Express-driven JSON api, like /api/path/to/resource. Perhaps you could redirect any requests with ?_escaped_fragment_ to /api/path/to/resource.html, and use content negotiation to render an HTML template of the content, rather than return the JSON data.

The only thing is, your Angular routes would need to match 1:1 with your REST API.

EDIT: I'm realizing that this has the potential to really muddy up your REST api and I don't recommend doing it outside of very simple use-cases where it might be a natural fit.

Instead, you can use an entirely different set of routes and controllers for your robot-friendly content. But then you're duplicating all of your AngularJS routes and controllers in Node/Express.

I've settled on generating snapshots with a headless browser, even though I feel that's a little less-than-ideal.

Reload activity in Android

Reloading your whole activity may be a heavy task. Just put the part of code that has to be refreshed in (kotlin):

override fun onResume() {
    super.onResume()
    //here...
}

Java:

@Override
public void onResume(){
    super.onResume();
    //here...

}

And call "onResume()" whenever needed.

How to receive POST data in django

You should have access to the POST dictionary on the request object.

Serializing with Jackson (JSON) - getting "No serializer found"?

For Oracle Java applications, add this after the ObjectMapper instantiation:

mapper.setVisibility(PropertyAccessor.FIELD, JsonAutoDetect.Visibility.ANY);

JavaScript Array splice vs slice

The slice() method returns a copy of a portion of an array into a new array object.

$scope.participantForms.slice(index, 1);

This does NOT change the participantForms array but returns a new array containing the single element found at the index position in the original array.

The splice() method changes the content of an array by removing existing elements and/or adding new elements.

$scope.participantForms.splice(index, 1);

This will remove one element from the participantForms array at the index position.

These are the Javascript native functions, AngularJS has nothing to do with them.

Simple JavaScript Checkbox Validation

If your checkbox has an ID of 'checkbox':

 if(document.getElementById('checkbox').checked == true){ // code here }

HTH

Fetching data from MySQL database using PHP, Displaying it in a form for editing

<?php
 include 'cdb.php';
$show=mysqli_query( $conn,"SELECT *FROM 'reg'");


while($row1= mysqli_fetch_array($show)) 

{

                 $id=$row1['id'];
                $Name= $row1['name'];
                $email = $row1['email'];
                $username = $row1['username'];
                $password= $row1['password'];
                $birthm = $row1['bmonth'];
                $birthd= $row1['bday'];
                $birthy= $row1['byear'];
                $gernder = $row1['gender'];
                $phone= $row1['phone'];
                $image=$row1['image'];
}


?>


<html>
<head><title>hey</head></title></head>

<body>

<form>
<table border="-2" bgcolor="pink" style="width: 12px; height: 100px;" >

    <th>
    id<input type="text" name="" style="width: 30px;" value= "<?php echo $row1['id']; ?>"  >
</th>

<br>
<br>

    <th>

 name <input type="text" name=""  style="width: 60px;" value= "<?php echo $row1['Name']; ?>" >
</th>

<th>
 email<input type="text" name="" style="width: 60px;" value= "<?php echo $row1['email']; ?>"  >
</th>
<th>
    username<input type="hidden" name="" style="width: 60px;"  value= "<?php echo $username['email']; ?>" >
</th>
<th>
    password<input type="hidden" name="" style="width: 60px;"  value= "<?php echo $row1['password']; ?>">
</ths>

<th>
    birthday month<input type="text" name="" style="width: 60px;"  value= "<?php echo $row1['birthm']; ?>">
</th>
<th>
   birthday day<input type="text" name="" style="width: 60px;"  value= "<?php echo $row1['birthd']; ?>">
</th>
<th>
       birthday year<input type="text" name="" style="width: 60px;" value= "<?php echo $row1['birthy']; ?>" >
</th>
<th>
    gender<input type="text" name="" style="width: 60px;" value= "<?php echo $row1['gender']; ?>">
</th>
<th>
    phone number<input type="text" name="" style="width: 60px;" value= "<?php echo $row1['phone']; ?>">
</th>
<th>
    <th>
     image<input type="text" name="" style="width: 60px;"  value= "<?php echo $row1['image']; ?>">
</th>

<th>

<font color="pink"> <a href="update.php">update</a></font>

</th>
</table>

</body>
</form>
</body>
</html>

Purge or recreate a Ruby on Rails database

According to Rails guide, this one liner should be used because it would load from the schema.rb instead of reloading the migration files one by one:

rake db:reset

IF...THEN...ELSE using XML

Personally, I would prefer

<IF>
  <TIME from="5pm" to="9pm" />
  <THEN>
    <!-- action -->
  </THEN>
  <ELSE>
    <!-- action -->
  </ELSE>
</IF>

In this way you don't need an id attribute to tie together the IF, THEN, ELSE tags

Giving my function access to outside variable

By default, when you are inside a function, you do not have access to the outer variables.


If you want your function to have access to an outer variable, you have to declare it as global, inside the function :

function someFuntion(){
    global $myArr;
    $myVal = //some processing here to determine value of $myVal
    $myArr[] = $myVal;
}

For more informations, see Variable scope.

But note that using global variables is not a good practice : with this, your function is not independant anymore.


A better idea would be to make your function return the result :

function someFuntion(){
    $myArr = array();       // At first, you have an empty array
    $myVal = //some processing here to determine value of $myVal
    $myArr[] = $myVal;      // Put that $myVal into the array
    return $myArr;
}

And call the function like this :

$result = someFunction();


Your function could also take parameters, and even work on a parameter passed by reference :

function someFuntion(array & $myArr){
    $myVal = //some processing here to determine value of $myVal
    $myArr[] = $myVal;      // Put that $myVal into the array
}

Then, call the function like this :

$myArr = array( ... );
someFunction($myArr);  // The function will receive $myArr, and modify it

With this :

  • Your function received the external array as a parameter
  • And can modify it, as it's passed by reference.
  • And it's better practice than using a global variable : your function is a unit, independant of any external code.


For more informations about that, you should read the Functions section of the PHP manual, and,, especially, the following sub-sections :

SQL Server : SUM() of multiple rows including where clauses

This will bring back totals per property and type

SELECT  PropertyID,
        TYPE,
        SUM(Amount)
FROM    yourTable
GROUP BY    PropertyID,
            TYPE

This will bring back only active values

SELECT  PropertyID,
        TYPE,
        SUM(Amount)
FROM    yourTable
WHERE   EndDate IS NULL
GROUP BY    PropertyID,
            TYPE

and this will bring back totals for properties

SELECT  PropertyID,
        SUM(Amount)
FROM    yourTable
WHERE   EndDate IS NULL
GROUP BY    PropertyID

......

Wait 5 seconds before executing next line

You have to put your code in the callback function you supply to setTimeout:

function stateChange(newState) {
    setTimeout(function () {
        if (newState == -1) {
            alert('VIDEO HAS STOPPED');
        }
    }, 5000);
}

Any other code will execute immediately.

System.Security.SecurityException when writing to Event Log

Though the installer answer is a good answer, it is not always practical when dealing with software you did not write. A simple answer is to create the log and the event source using the PowerShell command New-EventLog (http://technet.microsoft.com/en-us/library/hh849768.aspx)

Run PowerShell as an Administrator and run the following command changing out the log name and source that you need.

New-EventLog -LogName Application -Source TFSAggregator

I used it to solve the Event Log Exception when Aggregator runs issue from codeplex.

Apply a function to every row of a matrix or a data frame

In case you want to apply common functions such as sum or mean, you should use rowSums or rowMeans since they're faster than apply(data, 1, sum) approach. Otherwise, stick with apply(data, 1, fun). You can pass additional arguments after FUN argument (as Dirk already suggested):

set.seed(1)
m <- matrix(round(runif(20, 1, 5)), ncol=4)
diag(m) <- NA
m
     [,1] [,2] [,3] [,4]
[1,]   NA    5    2    3
[2,]    2   NA    2    4
[3,]    3    4   NA    5
[4,]    5    4    3   NA
[5,]    2    1    4    4

Then you can do something like this:

apply(m, 1, quantile, probs=c(.25,.5, .75), na.rm=TRUE)
    [,1] [,2] [,3] [,4] [,5]
25%  2.5    2  3.5  3.5 1.75
50%  3.0    2  4.0  4.0 3.00
75%  4.0    3  4.5  4.5 4.00

Get css top value as number not as string?

You can use the parseInt() function to convert the string to a number, e.g:

parseInt($('#elem').css('top'));

Update: (as suggested by Ben): You should give the radix too:

parseInt($('#elem').css('top'), 10);

Forces it to be parsed as a decimal number, otherwise strings beginning with '0' might be parsed as an octal number (might depend on the browser used).

GSON - Date format

This won't really work at all. There is no date type in JSON. I would recommend to serialize to ISO8601 back and forth (for format agnostics and JS compat). Consider that you have to know which fields contain dates.

Stored procedure - return identity as output parameter or scalar

Either as recordset or output parameter. The latter has less overhead and I'd tend to use that rather than a single column/row recordset.

If I expected to >1 row I'd use the OUTPUT clause and a recordset

Return values would normally be used for error handling.

How to detect chrome and safari browser (webkit)

jQuery provides that:

if ($.browser.webkit){
    ...
}

Further reading at http://api.jquery.com/jQuery.browser/

Update

As noted in other answers/comments, it's always better to check for feature support than agent info. jQuery also provides an object for that: jQuery.support. Check the documentation to see the detailed list features to check for.

How can I get terminal output in python?

You can use Popen in subprocess as they suggest.

with os, which is not recomment, it's like below:

import os
a  = os.popen('pwd').readlines()

How to get the innerHTML of selectable jquery element?

$(function() {
        $("#select-image").selectable({
            selected: function( event, ui ) { 
                var $variable = $('.ui-selected').html(); 
                console.log($variable);
            }
        });
    });

or

$(function() {
        $("#select-image").selectable({
            selected: function( event, ui ) { 
                var $variable = $('.ui-selected').text(); 
                console.log($variable);
            }
        });
    });

or

$(function() {
        $("#select-image").selectable({
            selected: function( event, ui ) { 
                var $variable = $('.ui-selected').val(); 
                console.log($variable);
            }
        });
    });

How to connect to SQL Server from command prompt with Windows authentication

After some tries, these are the samples I am using in order to connect:

Specifying the username and the password:

sqlcmd -S 211.11.111.111 -U NotSA -P NotTheSaPassword

Specifying the DB as well:

sqlcmd -S 211.11.111.111 -d SomeSpecificDatabase -U NotSA -P NotTheSaPassword

How to convert string to Date in Angular2 \ Typescript?

You can use date filter to convert in date and display in specific format.

In .ts file (typescript):

let dateString = '1968-11-16T00:00:00' 
let newDate = new Date(dateString);

In HTML:

{{dateString |  date:'MM/dd/yyyy'}}

Below are some formats which you can implement :

Backend:

public todayDate = new Date();

HTML :

<select>
<option value=""></option>
<option value="MM/dd/yyyy">[{{todayDate | date:'MM/dd/yyyy'}}]</option>
<option value="EEEE, MMMM d, yyyy">[{{todayDate | date:'EEEE, MMMM d, yyyy'}}]</option>
<option value="EEEE, MMMM d, yyyy h:mm a">[{{todayDate | date:'EEEE, MMMM d, yyyy h:mm a'}}]</option>
<option value="EEEE, MMMM d, yyyy h:mm:ss a">[{{todayDate | date:'EEEE, MMMM d, yyyy h:mm:ss a'}}]</option>
<option value="MM/dd/yyyy h:mm a">[{{todayDate | date:'MM/dd/yyyy h:mm a'}}]</option>
<option value="MM/dd/yyyy h:mm:ss a">[{{todayDate | date:'MM/dd/yyyy h:mm:ss a'}}]</option>
<option value="MMMM d">[{{todayDate | date:'MMMM d'}}]</option>   
<option value="yyyy-MM-ddTHH:mm:ss">[{{todayDate | date:'yyyy-MM-ddTHH:mm:ss'}}]</option>
<option value="h:mm a">[{{todayDate | date:'h:mm a'}}]</option>
<option value="h:mm:ss a">[{{todayDate | date:'h:mm:ss a'}}]</option>      
<option value="EEEE, MMMM d, yyyy hh:mm:ss a">[{{todayDate | date:'EEEE, MMMM d, yyyy hh:mm:ss a'}}]</option>
<option value="MMMM yyyy">[{{todayDate | date:'MMMM yyyy'}}]</option> 
</select>

jQuery if statement, syntax

jQuery is just a library which enhances the capabilities of the DOM within a web browser; the underlying language is JavaScript, which has, as you might hope to expect from a programming language, the ability to perform conditional logic, i.e.

if( condition ) {
    // do something
}

Testing two conditions is straightforward, too:

if( A && B ) {
    // do something
}

Dear God, I hope this isn't a troll...

How can I use a carriage return in a HTML tooltip?

Razor Syntax

In the case of ASP.NET MVC you can just store the title as a variable as use \r\n and it'll work.

@{ 
    var logTooltip = "Sunday\r\nMonday\r\netc.";
}

<h3 title="@logTooltip">Logs</h3>

Setting HttpContext.Current.Session in a unit test

The answer @Ro Hit gave helped me a lot, but I was missing the user credentials because I had to fake a user for authentication unit testing. Hence, let me describe how I solved it.

According to this, if you add the method

    // using System.Security.Principal;
    GenericPrincipal FakeUser(string userName)
    {
        var fakeIdentity = new GenericIdentity(userName);
        var principal = new GenericPrincipal(fakeIdentity, null);
        return principal;
    }

and then append

    HttpContext.Current.User = FakeUser("myDomain\\myUser");

to the last line of the TestSetup method you're done, the user credentials are added and ready to be used for authentication testing.

I also noticed that there are other parts in HttpContext you might require, such as the .MapPath() method. There is a FakeHttpContext available, which is described here and can be installed via NuGet.

Best way to return a value from a python script

If you want your script to return values, just do return [1,2,3] from a function wrapping your code but then you'd have to import your script from another script to even have any use for that information:

Return values (from a wrapping-function)

(again, this would have to be run by a separate Python script and be imported in order to even do any good):

import ...
def main():
    # calculate stuff
    return [1,2,3]

Exit codes as indicators

(This is generally just good for when you want to indicate to a governor what went wrong or simply the number of bugs/rows counted or w/e. Normally 0 is a good exit and >=1 is a bad exit but you could inter-prate them in any way you want to get data out of it)

import sys
# calculate and stuff
sys.exit(100)

And exit with a specific exit code depending on what you want that to tell your governor. I used exit codes when running script by a scheduling and monitoring environment to indicate what has happened.

(os._exit(100) also works, and is a bit more forceful)

Stdout as your relay

If not you'd have to use stdout to communicate with the outside world (like you've described). But that's generally a bad idea unless it's a parser executing your script and can catch whatever it is you're reporting to.

import sys
# calculate stuff
sys.stdout.write('Bugs: 5|Other: 10\n')
sys.stdout.flush()
sys.exit(0)

Are you running your script in a controlled scheduling environment then exit codes are the best way to go.

Files as conveyors

There's also the option to simply write information to a file, and store the result there.

# calculate
with open('finish.txt', 'wb') as fh:
    fh.write(str(5)+'\n')

And pick up the value/result from there. You could even do it in a CSV format for others to read simplistically.

Sockets as conveyors

If none of the above work, you can also use network sockets locally *(unix sockets is a great way on nix systems). These are a bit more intricate and deserve their own post/answer. But editing to add it here as it's a good option to communicate between processes. Especially if they should run multiple tasks and return values.

Remove a cookie

To remove all cookies you could write:

foreach ($_COOKIE as $key => $value) {
    unset($value);
    setcookie($key, '', time() - 3600);
}

How do I parallelize a simple Python loop?

very simple example of parallel processing is

from multiprocessing import Process

output1 = list()
output2 = list()
output3 = list()

def yourfunction():
    for j in range(0, 10):
        # calc individual parameter value
        parameter = j * offset
        # call the calculation
        out1, out2, out3 = calc_stuff(parameter=parameter)

        # put results into correct output list
        output1.append(out1)
        output2.append(out2)
        output3.append(out3)

if __name__ == '__main__':
    p = Process(target=pa.yourfunction, args=('bob',))
    p.start()
    p.join()

MySQL: Error Code: 1118 Row size too large (> 8126). Changing some columns to TEXT or BLOB

The following worked for me, nothing else -:

SET GLOBAL innodb_log_buffer_size = 80*1024*1024*1024;

and

SET GLOBAL innodb_strict_mode = 0;

Hope this helps someone because it wasted couple of days of my time as I was trying to do this in my.cnf with no joy.

Get the IP Address of local computer

The problem with all the approaches based on gethostbyname is that you will not get all IP addresses assigned to a particular machine. Servers usually have more than one adapter.

Here is an example of how you can iterate through all Ipv4 and Ipv6 addresses on the host machine:

void ListIpAddresses(IpAddresses& ipAddrs)
{
  IP_ADAPTER_ADDRESSES* adapter_addresses(NULL);
  IP_ADAPTER_ADDRESSES* adapter(NULL);

  // Start with a 16 KB buffer and resize if needed -
  // multiple attempts in case interfaces change while
  // we are in the middle of querying them.
  DWORD adapter_addresses_buffer_size = 16 * KB;
  for (int attempts = 0; attempts != 3; ++attempts)
  {
    adapter_addresses = (IP_ADAPTER_ADDRESSES*)malloc(adapter_addresses_buffer_size);
    assert(adapter_addresses);

    DWORD error = ::GetAdaptersAddresses(
      AF_UNSPEC, 
      GAA_FLAG_SKIP_ANYCAST | 
        GAA_FLAG_SKIP_MULTICAST | 
        GAA_FLAG_SKIP_DNS_SERVER |
        GAA_FLAG_SKIP_FRIENDLY_NAME, 
      NULL, 
      adapter_addresses,
      &adapter_addresses_buffer_size);

    if (ERROR_SUCCESS == error)
    {
      // We're done here, people!
      break;
    }
    else if (ERROR_BUFFER_OVERFLOW == error)
    {
      // Try again with the new size
      free(adapter_addresses);
      adapter_addresses = NULL;

      continue;
    }
    else
    {
      // Unexpected error code - log and throw
      free(adapter_addresses);
      adapter_addresses = NULL;

      // @todo
      LOG_AND_THROW_HERE();
    }
  }

  // Iterate through all of the adapters
  for (adapter = adapter_addresses; NULL != adapter; adapter = adapter->Next)
  {
    // Skip loopback adapters
    if (IF_TYPE_SOFTWARE_LOOPBACK == adapter->IfType)
    {
      continue;
    }

    // Parse all IPv4 and IPv6 addresses
    for (
      IP_ADAPTER_UNICAST_ADDRESS* address = adapter->FirstUnicastAddress; 
      NULL != address;
      address = address->Next)
    {
      auto family = address->Address.lpSockaddr->sa_family;
      if (AF_INET == family)
      {
        // IPv4
        SOCKADDR_IN* ipv4 = reinterpret_cast<SOCKADDR_IN*>(address->Address.lpSockaddr);

        char str_buffer[INET_ADDRSTRLEN] = {0};
        inet_ntop(AF_INET, &(ipv4->sin_addr), str_buffer, INET_ADDRSTRLEN);
        ipAddrs.mIpv4.push_back(str_buffer);
      }
      else if (AF_INET6 == family)
      {
        // IPv6
        SOCKADDR_IN6* ipv6 = reinterpret_cast<SOCKADDR_IN6*>(address->Address.lpSockaddr);

        char str_buffer[INET6_ADDRSTRLEN] = {0};
        inet_ntop(AF_INET6, &(ipv6->sin6_addr), str_buffer, INET6_ADDRSTRLEN);

        std::string ipv6_str(str_buffer);

        // Detect and skip non-external addresses
        bool is_link_local(false);
        bool is_special_use(false);

        if (0 == ipv6_str.find("fe"))
        {
          char c = ipv6_str[2];
          if (c == '8' || c == '9' || c == 'a' || c == 'b')
          {
            is_link_local = true;
          }
        }
        else if (0 == ipv6_str.find("2001:0:"))
        {
          is_special_use = true;
        }

        if (! (is_link_local || is_special_use))
        {
          ipAddrs.mIpv6.push_back(ipv6_str);
        }
      }
      else
      {
        // Skip all other types of addresses
        continue;
      }
    }
  }

  // Cleanup
  free(adapter_addresses);
  adapter_addresses = NULL;

  // Cheers!
}

How do I get Flask to run on port 80?

If you use the following to change the port or host:

if __name__ == '__main__':
  app.run(host='0.0.0.0', port=80)

use the following code to start the server (my main entrance for flask is app.py):

python app.py

instead of using:

flask run

Autowiring two beans implementing same interface - how to set default bean to autowire?

What about @Primary?

Indicates that a bean should be given preference when multiple candidates are qualified to autowire a single-valued dependency. If exactly one 'primary' bean exists among the candidates, it will be the autowired value. This annotation is semantically equivalent to the <bean> element's primary attribute in Spring XML.

@Primary
public class HibernateDeviceDao implements DeviceDao

Or if you want your Jdbc version to be used by default:

<bean id="jdbcDeviceDao" primary="true" class="com.initech.service.dao.jdbc.JdbcDeviceDao">

@Primary is also great for integration testing when you can easily replace production bean with stubbed version by annotating it.

Storing Objects in HTML5 localStorage

For Typescript users willing to set and get typed properties:

/**
 * Silly wrapper to be able to type the storage keys
 */
export class TypedStorage<T> {

    public removeItem(key: keyof T): void {
        localStorage.removeItem(key);
    }

    public getItem<K extends keyof T>(key: K): T[K] | null {
        const data: string | null =  localStorage.getItem(key);
        return JSON.parse(data);
    }

    public setItem<K extends keyof T>(key: K, value: T[K]): void {
        const data: string = JSON.stringify(value);
        localStorage.setItem(key, data);
    }
}

Example usage:

// write an interface for the storage
interface MyStore {
   age: number,
   name: string,
   address: {city:string}
}

const storage: TypedStorage<MyStore> = new TypedStorage<MyStore>();

storage.setItem("wrong key", ""); // error unknown key
storage.setItem("age", "hello"); // error, age should be number
storage.setItem("address", {city:"Here"}); // ok

const address: {city:string} = storage.getItem("address");

Display PNG image as response to jQuery AJAX request

You'll need to send the image back base64 encoded, look at this: http://php.net/manual/en/function.base64-encode.php

Then in your ajax call change the success function to this:

$('.div_imagetranscrits').html('<img src="data:image/png;base64,' + data + '" />');

How do I find the PublicKeyToken for a particular dll?

Assembly.LoadFile(@"C:\Windows\Microsoft.NET\Framework\v4.0.30319\system.data.dll").FullName

Will result in

System.Data, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089

Why is it said that "HTTP is a stateless protocol"?

From Wikipedia:

HTTP is a stateless protocol. A stateless protocol does not require the server to retain information or status about each user for the duration of multiple requests.

But some web applications may have to track the user's progress from page to page, for example when a web server is required to customize the content of a web page for a user. Solutions for these cases include:

  • the use of HTTP cookies.
  • server side sessions,
  • hidden variables (when the current page contains a form), and
  • URL-rewriting using URI-encoded parameters, e.g., /index.php?session_id=some_unique_session_code.

What makes the protocol stateless is that the server is not required to track state over multiple requests, not that it cannot do so if it wants to. This simplifies the contract between client and server, and in many cases (for instance serving up static data over a CDN) minimizes the amount of data that needs to be transferred. If servers were required to maintain the state of clients' visits the structure of issuing and responding to requests would be more complex. As it is, the simplicity of the model is one of its greatest features.

How to set a maximum execution time for a mysql query?

I thought it has been around a little longer, but according to this,

MySQL 5.7.4 introduces the ability to set server side execution time limits, specified in milliseconds, for top level read-only SELECT statements.

SELECT 
/*+ MAX_EXECUTION_TIME(1000) */ --in milliseconds
* 
FROM table;

Note that this only works for read-only SELECT statements.

Update: This variable was added in MySQL 5.7.4 and renamed to max_execution_time in MySQL 5.7.8. (source)

Labeling file upload button

It is normally provided by the browser and hard to change, so the only way around it will be a CSS/JavaScript hack,

See the following links for some approaches:

Angular routerLink does not navigate to the corresponding component

I'm aware this question is fairly old by now, and you've most likely fixed it by now, but I'd like to post here as reference for anyone that finds this post while troubleshooting this issue is that this sort of thing won't work if your Anchor tags are in the Index.html. It needs to be in one of the components

How to replicate vector in c?

They would start by hiding the defining a structure that would hold members necessary for the implementation. Then providing a group of functions that would manipulate the contents of the structure.

Something like this:

typedef struct vec
{
    unsigned char* _mem;
    unsigned long _elems;
    unsigned long _elemsize;
    unsigned long _capelems;
    unsigned long _reserve;
};

vec* vec_new(unsigned long elemsize)
{
    vec* pvec = (vec*)malloc(sizeof(vec));
    pvec->_reserve = 10;
    pvec->_capelems = pvec->_reserve;
    pvec->_elemsize = elemsize;
    pvec->_elems = 0;
    pvec->_mem = (unsigned char*)malloc(pvec->_capelems * pvec->_elemsize);
    return pvec;
}

void vec_delete(vec* pvec)
{
    free(pvec->_mem);
    free(pvec);
}

void vec_grow(vec* pvec)
{
    unsigned char* mem = (unsigned char*)malloc((pvec->_capelems + pvec->_reserve) * pvec->_elemsize);
    memcpy(mem, pvec->_mem, pvec->_elems * pvec->_elemsize);
    free(pvec->_mem);
    pvec->_mem = mem;
    pvec->_capelems += pvec->_reserve;
}

void vec_push_back(vec* pvec, void* data, unsigned long elemsize)
{
    assert(elemsize == pvec->_elemsize);
    if (pvec->_elems == pvec->_capelems) {
        vec_grow(pvec);
    }
    memcpy(pvec->_mem + (pvec->_elems * pvec->_elemsize), (unsigned char*)data, pvec->_elemsize);
    pvec->_elems++;    
}

unsigned long vec_length(vec* pvec)
{
    return pvec->_elems;
}

void* vec_get(vec* pvec, unsigned long index)
{
    assert(index < pvec->_elems);
    return (void*)(pvec->_mem + (index * pvec->_elemsize));
}

void vec_copy_item(vec* pvec, void* dest, unsigned long index)
{
    memcpy(dest, vec_get(pvec, index), pvec->_elemsize);
}

void playwithvec()
{
    vec* pvec = vec_new(sizeof(int));

    for (int val = 0; val < 1000; val += 10) {
        vec_push_back(pvec, &val, sizeof(val));
    }

    for (unsigned long index = (int)vec_length(pvec) - 1; (int)index >= 0; index--) {
        int val;
        vec_copy_item(pvec, &val, index);
        printf("vec(%d) = %d\n", index, val);
    }

    vec_delete(pvec);
}

Further to this they would achieve encapsulation by using void* in the place of vec* for the function group, and actually hide the structure definition from the user by defining it within the C module containing the group of functions rather than the header. Also they would hide the functions that you would consider to be private, by leaving them out from the header and simply prototyping them only in the C module.

Is it possible that one domain name has multiple corresponding IP addresses?

Yes this is possible, however not convenient as Jens said. Using Next generation load balancers like Alteon, which Uses a proprietary protocol called DSSP(Distributed site state Protocol) which performs regular site checks to make sure that the service is available both Locally or Globally i.e different geographical areas. You need to however in your Master DNS to delegate the URL or Service to the device by configuring it as an Authoritative Name Server for that IP or Service. By doing this, the device answers DNS queries where it will resolve the IP that has a service by Round-Robin or is not congested according to how you have chosen from several metrics.

nginx: how to create an alias url route?

server {
  server_name example.com;
  root /path/to/root;
  location / {
    # bla bla
  }
  location /demo {
    alias /path/to/root/production/folder/here;
  }
}

If you need to use try_files inside /demo you'll need to replace alias with a root and do a rewrite because of the bug explained here

Can you create nested WITH clauses for Common Table Expressions?

With does not work embedded, but it does work consecutive

;WITH A AS(
...
),
B AS(
...
)
SELECT *
FROM A
UNION ALL
SELECT *
FROM B

EDIT Fixed the syntax...

Also, have a look at the following example

SQLFiddle DEMO

How to get the size of a JavaScript object?

This is a hacky method, but i tried it twice with different numbers and it seems to be consistent.

What you can do is to try and allocate a huge number of objects, like one or two million objects of the kind you want. Put the objects in an array to prevent the garbage collector from releasing them (note that this will add a slight memory overhead because of the array, but i hope this shouldn't matter and besides if you are going to worry about objects being in memory, you store them somewhere). Add an alert before and after the allocation and in each alert check how much memory the Firefox process is taking. Before you open the page with the test, make sure you have a fresh Firefox instance. Open the page, note the memory usage after the "before" alert is shown. Close the alert, wait for the memory to be allocated. Subtract the new memory from the older and divide it by the amount of allocations. Example:

function Marks()
{
  this.maxMarks = 100;
}

function Student()
{
  this.firstName = "firstName";
  this.lastName = "lastName";
  this.marks = new Marks();
}

var manyObjects = new Array();
alert('before');
for (var i=0; i<2000000; i++)
    manyObjects[i] = new Student();
alert('after');

I tried this in my computer and the process had 48352K of memory when the "before" alert was shown. After the allocation, Firefox had 440236K of memory. For 2million allocations, this is about 200 bytes for each object.

I tried it again with 1million allocations and the result was similar: 196 bytes per object (i suppose the extra data in 2mill was used for Array).

So, here is a hacky method that might help you. JavaScript doesn't provide a "sizeof" method for a reason: each JavaScript implementaion is different. In Google Chrome for example the same page uses about 66 bytes for each object (judging from the task manager at least).

How to get browser width using JavaScript code?

An important addition to Travis' answer; you need to put the getWidth() up in your document body to make sure that the scrollbar width is counted, else scrollbar width of the browser subtracted from getWidth(). What i did ;

<body>
<script>
function getWidth(){
return Math.max(document.body.scrollWidth,
document.documentElement.scrollWidth,
document.body.offsetWidth,
document.documentElement.offsetWidth,
document.documentElement.clientWidth);
}
var aWidth=getWidth();
</script>
</body>

and call aWidth variable anywhere afterwards.

Default nginx client_max_body_size

You can increase body size in nginx configuration file as

sudo nano /etc/nginx/nginx.conf

client_max_body_size 100M;

Restart nginx to apply the changes.

sudo service nginx restart

Pattern matching using a wildcard

glob2rx() converts a pattern including a wildcard into the equivalent regular expression. You then need to pass this regular expression onto one of R's pattern matching tools.

If you want to match "blue*" where * has the usual wildcard, not regular expression, meaning we use glob2rx() to convert the wildcard pattern into a useful regular expression:

> glob2rx("blue*")
[1] "^blue"

The returned object is a regular expression.

Given your data:

x <- c('red','blue1','blue2', 'red2')

we can pattern match using grep() or similar tools:

> grx <- glob2rx("blue*")
> grep(grx, x)
[1] 2 3
> grep(grx, x, value = TRUE)
[1] "blue1" "blue2"
> grepl(grx, x)
[1] FALSE  TRUE  TRUE FALSE

As for the selecting rows problem you posted

> a <- data.frame(x =  c('red','blue1','blue2', 'red2'))
> with(a, a[grepl(grx, x), ])
[1] blue1 blue2
Levels: blue1 blue2 red red2
> with(a, a[grep(grx, x), ])
[1] blue1 blue2
Levels: blue1 blue2 red red2

or via subset():

> with(a, subset(a, subset = grepl(grx, x)))
      x
2 blue1
3 blue2

Hope that explains what grob2rx() does and how to use it?

What do *args and **kwargs mean?

Notice the cool thing in S.Lott's comment - you can also call functions with *mylist and **mydict to unpack positional and keyword arguments:

def foo(a, b, c, d):
  print a, b, c, d

l = [0, 1]
d = {"d":3, "c":2}

foo(*l, **d)

Will print: 0 1 2 3