Programs & Examples On #Fusebox

Fusebox is a coding methodology for application development centered around the use of switch statements and naming conventions to organize code.

Using python's eval() vs. ast.literal_eval()?

eval: This is very powerful, but is also very dangerous if you accept strings to evaluate from untrusted input. Suppose the string being evaluated is "os.system('rm -rf /')" ? It will really start deleting all the files on your computer.

ast.literal_eval: Safely evaluate an expression node or a string containing a Python literal or container display. The string or node provided may only consist of the following Python literal structures: strings, bytes, numbers, tuples, lists, dicts, sets, booleans, None, bytes and sets.

Syntax:

eval(expression, globals=None, locals=None)
import ast
ast.literal_eval(node_or_string)

Example:

# python 2.x - doesn't accept operators in string format
import ast
ast.literal_eval('[1, 2, 3]')  # output: [1, 2, 3]
ast.literal_eval('1+1') # output: ValueError: malformed string


# python 3.0 -3.6
import ast
ast.literal_eval("1+1") # output : 2
ast.literal_eval("{'a': 2, 'b': 3, 3:'xyz'}") # output : {'a': 2, 'b': 3, 3:'xyz'}
# type dictionary
ast.literal_eval("",{}) # output : Syntax Error required only one parameter
ast.literal_eval("__import__('os').system('rm -rf /')") # output : error

eval("__import__('os').system('rm -rf /')") 
# output : start deleting all the files on your computer.
# restricting using global and local variables
eval("__import__('os').system('rm -rf /')",{'__builtins__':{}},{})
# output : Error due to blocked imports by passing  '__builtins__':{} in global

# But still eval is not safe. we can access and break the code as given below
s = """
(lambda fc=(
lambda n: [
    c for c in 
        ().__class__.__bases__[0].__subclasses__() 
        if c.__name__ == n
    ][0]
):
fc("function")(
    fc("code")(
        0,0,0,0,"KABOOM",(),(),(),"","",0,""
    ),{}
)()
)()
"""
eval(s, {'__builtins__':{}})

In the above code ().__class__.__bases__[0] nothing but object itself. Now we instantiated all the subclasses, here our main enter code hereobjective is to find one class named n from it.

We need to code object and function object from instantiated subclasses. This is an alternative way from CPython to access subclasses of object and attach the system.

From python 3.7 ast.literal_eval() is now stricter. Addition and subtraction of arbitrary numbers are no longer allowed. link

What is the Oracle equivalent of SQL Server's IsNull() function?

You can use the condition if x is not null then.... It's not a function. There's also the NVL() function, a good example of usage here: NVL function ref.

Could not find an implementation of the query pattern

For those of you (like me) that wasted too much time from this error:

I had received the same error: "Could not find implementation of query Pattern for source type 'DbSet'" but the solution for me was fixing a mistake at the DbContext level.

When I created my context I had this:

public class ContactContext : DbContext
    {
        public ContactContext() : base() { }

        public DbSet Contacts { get; set; }
    }

And my Repository (I was following a Repository pattern in ASP.NET guide) looked like this:

public Contact FindById(int id)
    {       
        var contact = from c in _db.Contacts where c.Id == id select c;
        return contact;
    }

My issue came from the initial setup of my DbContext, when I used DbSet as a generic instead of the type.

I changed public DbSet Contacts { get; set; } to public DbSet<Contact> Contacts { get; set; } and suddenly the query was recognized.


This is probably what k.m says in his answer, but since he mentioned IEnumerable<t> and not DbSet<<YourDomainObject>> I had to dig around in the code for a couple hours to find the line that caused this headache.

Regular Expression Match to test for a valid year

This works for 1900 to 2099:

/(?:(?:19|20)[0-9]{2})/

How to send HTTP request in java?

Here's a complete Java 7 program:

class GETHTTPResource {
  public static void main(String[] args) throws Exception {
    try (java.util.Scanner s = new java.util.Scanner(new java.net.URL("http://tools.ietf.org/rfc/rfc768.txt").openStream())) {
      System.out.println(s.useDelimiter("\\A").next());
    }
  }
}

The new try-with-resources will auto-close the Scanner, which will auto-close the InputStream.

Preventing SQL injection in Node.js

Mysql-native has been outdated so it became MySQL2 that is a new module created with the help of the original MySQL module's team. This module has more features and I think it has what you want as it has prepared statements(by using.execute()) like in PHP for more security.

It's also very active(the last change was from 2-1 days) I didn't try it before but I think it's what you want and more.

MVC 4 @Scripts "does not exist"

I upgraded from Beta to RC and faced 'Scripts' does not exist issue. Surfed all over the web and the final solution is what N40JPJ said plus another workaroudn:

Copy the following in View\Web.config :

  <namespaces>
    <add namespace="System.Web.Mvc" />
    <add namespace="System.Web.Mvc.Ajax" />
    <add namespace="System.Web.Mvc.Html" />
    <add namespace="System.Web.Routing" />
    <add namespace="System.Web.Optimization"/>
    <add namespace="System.Web.Helpers"/>
  </namespaces>

and the following inside View\Shared_Layout.cshtml

@if (IsSectionDefined("scripts")) 
{
       @RenderSection("scripts", required: false)
}

Hope it helps.

How to test if string exists in file with Bash?

grep -Fxq "String to be found" | ls -a
  • grep will helps you to check content
  • ls will list all the Files

Python: For each list element apply a function across the list

If you don't mind importing the numpy package, it has a lot of convenient functionality built in. It's likely to be much more efficient to use their data structures than lists of lists, etc.

from __future__ import division

import numpy

data = numpy.asarray([1,2,3,4,5])
dists = data.reshape((1,5)) / data.reshape((5,1))

print dists

which = dists.argmin()
(r,c) = (which // 5, which % 5) # assumes C ordering

# pick whichever is most appropriate for you...
minval = dists[r,c]
minval = dists.min()
minval = dists.ravel()[which]

What is a unix command for deleting the first N characters of a line?

tail -f logfile | grep org.springframework | cut -c 900-

would remove the first 900 characters

cut uses 900- to show the 900th character to the end of the line

however when I pipe all of this through grep I don't get anything

Converting camel case to underscore case in ruby

Here's how Rails does it:

   def underscore(camel_cased_word)
     camel_cased_word.to_s.gsub(/::/, '/').
       gsub(/([A-Z]+)([A-Z][a-z])/,'\1_\2').
       gsub(/([a-z\d])([A-Z])/,'\1_\2').
       tr("-", "_").
       downcase
   end

How to make a <svg> element expand or contract to its parent container?

The viewBox isn't the height of the container, it's the size of your drawing. Define your viewBox to be 100 units in width, then define your rect to be 10 units. After that, however large you scale the SVG, the rect will be 10% the width of the image.

The name 'ViewBag' does not exist in the current context

I had this problem after changing the Application's Default namespace in the Properties dialog.

The ./Views/Web.Config contained a reference to the old namespace

String Resource new line /n not possible?

I just faced this issue. didn't work on TextView with constraint parameters. Adding android:lines="2" seems to fix this.

How to process a file in PowerShell line-by-line as a stream

If you are really about to work on multi-gigabyte text files then do not use PowerShell. Even if you find a way to read it faster processing of huge amount of lines will be slow in PowerShell anyway and you cannot avoid this. Even simple loops are expensive, say for 10 million iterations (quite real in your case) we have:

# "empty" loop: takes 10 seconds
measure-command { for($i=0; $i -lt 10000000; ++$i) {} }

# "simple" job, just output: takes 20 seconds
measure-command { for($i=0; $i -lt 10000000; ++$i) { $i } }

# "more real job": 107 seconds
measure-command { for($i=0; $i -lt 10000000; ++$i) { $i.ToString() -match '1' } }

UPDATE: If you are still not scared then try to use the .NET reader:

$reader = [System.IO.File]::OpenText("my.log")
try {
    for() {
        $line = $reader.ReadLine()
        if ($line -eq $null) { break }
        # process the line
        $line
    }
}
finally {
    $reader.Close()
}

UPDATE 2

There are comments about possibly better / shorter code. There is nothing wrong with the original code with for and it is not pseudo-code. But the shorter (shortest?) variant of the reading loop is

$reader = [System.IO.File]::OpenText("my.log")
while($null -ne ($line = $reader.ReadLine())) {
    $line
}

findViewByID returns null

FindViewById can be null if you call the wrong super constructor in a custom view. The ID tag is part of attrs, so if you ignore attrs, you delete the ID.

This would be wrong

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

This is correct

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

How to do a FULL OUTER JOIN in MySQL?

what'd you say about Cross join solution?

SELECT t1.*, t2.*
FROM table1 t1
INNER JOIN table2 t2 
ON 1=1;

COALESCE with Hive SQL

If customer primary contact medium is email, if email is null then phonenumber, and if phonenumber is also null then address. It would be written using COALESCE as

coalesce(email,phonenumber,address) 

while the same in hive can be achieved by chaining together nvl as

nvl(email,nvl(phonenumber,nvl(address,'n/a')))

How to change the URL from "localhost" to something else, on a local system using wampserver?

for new version of Wamp

<VirtualHost *:80>
  ServerName domain.local
  DocumentRoot C:/wamp/www/domain/
  <Directory "C:/wamp/www/domain/">
      Options +Indexes +FollowSymLinks +MultiViews
      AllowOverride All
      Require local
  </Directory>
</VirtualHost>

Difference between "as $key => $value" and "as $value" in PHP foreach

if the array looks like:

  • $featured["fruit"] = "orange";
  • $featured["fruit"] = "banana";
  • $featured["vegetable"] = "carrot";

the $key will hold the type (fruit or vegetable) for each array value (orange, banana or carrot)

SELECT list is not in GROUP BY clause and contains nonaggregated column .... incompatible with sql_mode=only_full_group_by

go to the phpmyadmin and open the console and execute this request

SET GLOBAL sql_mode=(SELECT REPLACE(@@sql_mode,'ONLY_FULL_GROUP_BY',''));

Unsupported operation :not writeable python

file = open('ValidEmails.txt','wb')
file.write(email.encode('utf-8', 'ignore'))

This is solve your encode error also.

How do I remove the height style from a DIV using jQuery?

you can try this:

$('div#someDiv').height('');

Appending pandas dataframes generated in a for loop

you can try this.

data_you_need=pd.DataFrame()
for infile in glob.glob("*.xlsx"):
    data = pandas.read_excel(infile)
    data_you_need=data_you_need.append(data,ignore_index=True)

I hope it can help.

heroku - how to see all the logs

heroku logs -t shows us the live logs. heroku logs -n 1500 for specific number of logs

But still I would recommend to use paper trail add-on which have certain benefits and has free basic plan.

Unexpected 'else' in "else" error

I would suggest to read up a bit on the syntax. See here.

if (dsnt<0.05) {
  wilcox.test(distance[result=='nt'],distance[result=='t'],alternative=c("two.sided"),paired=TRUE) 
} else if (dst<0.05) {
    wilcox.test(distance[result=='nt'],distance[result=='t'],alternative=c("two.sided"),paired=TRUE)
} else 
  t.test(distance[result=='nt'],distance[result=='t'],alternative=c("two.sided"),paired=TRUE)

TypeError : Unhashable type

You are creating a set via set(...) call, and set needs hashable items. You can't have set of lists. Because list's arent hashable.

[[(a,b) for a in range(3)] for b in range(3)] is a list. It's not a hashable type. The __hash__ you saw in dir(...) isn't a method, it's just None.

A list comprehension returns a list, you don't need to explicitly use list there, just use:

>>> [[(a,b) for a in range(3)] for b in range(3)]
[[(0, 0), (1, 0), (2, 0)], [(0, 1), (1, 1), (2, 1)], [(0, 2), (1, 2), (2, 2)]]

Try those:

>>> a = {1, 2, 3}
>>> b= [1, 2, 3]
>>> type(a)
<class 'set'>
>>> type(b)
<class 'list'>
>>> {1, 2, []}
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: unhashable type: 'list'
>>> print([].__hash__)
None
>>> [[],[],[]] #list of lists
[[], [], []]
>>> {[], [], []} #set of lists
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: unhashable type: 'list'

Remove all files in a directory

os.remove doesn't resolve unix-style patterns. If you are on a unix-like system you can:

os.system('rm '+test)

Else you can:

import glob, os
test = '/path/*'
r = glob.glob(test)
for i in r:
   os.remove(i)

Extreme wait-time when taking a SQL Server database offline

anytime you run into this type of thing you should always think of your transaction log. The alter db statment with rollback immediate indicates this to be the case. Check this out: http://msdn.microsoft.com/en-us/library/ms189085.aspx

Bone up on checkpoints, etc. You need to decide if the transactions in your log are worth saving or not and then pick the mode to run your db in accordingly. There's really no reason for you to have to wait but also no reason for you to lose data either - you can have both.

Getting all types in a namespace via reflection

Following code prints names of classes in specified namespace defined in current assembly.
As other guys pointed out, a namespace can be scattered between different modules, so you need to get a list of assemblies first.

string nspace = "...";

var q = from t in Assembly.GetExecutingAssembly().GetTypes()
        where t.IsClass && t.Namespace == nspace
        select t;
q.ToList().ForEach(t => Console.WriteLine(t.Name));

How to check String in response body with mockMvc

You can use getContentAsString method to get the response data as string.

    String payload = "....";
    String apiToTest = "....";
    
    MvcResult mvcResult = mockMvc.
                perform(post(apiToTest).
                content(payload).
                contentType(MediaType.APPLICATION_JSON)).
                andReturn();
    
    String responseData = mvcResult.getResponse().getContentAsString();

You can refer this link for test application.

matrix multiplication algorithm time complexity

In matrix multiplication there are 3 for loop, we are using since execution of each for loop requires time complexity O(n). So for three loops it becomes O(n^3)

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 decrease prod bundle size?

Firstly, vendor bundles are huge simply because Angular 2 relies on a lot of libraries. Minimum size for Angular 2 app is around 500KB (250KB in some cases, see bottom post).
Tree shaking is properly used by angular-cli.
Do not include .map files, because used only for debugging. Moreover, if you use hot replacement module, remove it to lighten vendor.

To pack for production, I personnaly use Webpack (and angular-cli relies on it too), because you can really configure everything for optimization or debugging.
If you want to use Webpack, I agree it is a bit tricky a first view, but see tutorials on the net, you won't be disappointed.
Else, use angular-cli, which get the job done really well.

Using Ahead-of-time compilation is mandatory to optimize apps, and shrink Angular 2 app to 250KB.

Here is a repo I created (github.com/JCornat/min-angular) to test minimal Angular bundle size, and I obtain 384kB. I am sure there is easy way to optimize it.

Talking about big apps, using the AngularClass/angular-starter configuration, the same as in the repo above, my bundle size for big apps (150+ components) went from 8MB (4MB without map files) to 580kB.

How to fill background image of an UIView

For Swift 3.0 use the following code:

    UIGraphicsBeginImageContext(self.view.frame.size)
    UIImage(named: "bg.png")?.drawAsPattern(in: self.view.bounds)
    let image: UIImage = UIGraphicsGetImageFromCurrentImageContext()!
    UIGraphicsEndImageContext()
    self.view.backgroundColor = UIColor(patternImage: image)

New features in java 7

New Feature of Java Standard Edition (JSE 7)

  1. Decorate Components with the JLayer Class:

    The JLayer class is a flexible and powerful decorator for Swing components. The JLayer class in Java SE 7 is similar in spirit to the JxLayer project project at java.net. The JLayer class was initially based on the JXLayer project, but its API evolved separately.

  2. Strings in switch Statement:

    In the JDK 7 , we can use a String object in the expression of a switch statement. The Java compiler generates generally more efficient bytecode from switch statements that use String objects than from chained if-then-else statements.

  3. Type Inference for Generic Instance:

    We can replace the type arguments required to invoke the constructor of a generic class with an empty set of type parameters (<>) as long as the compiler can infer the type arguments from the context. This pair of angle brackets is informally called the diamond. Java SE 7 supports limited type inference for generic instance creation; you can only use type inference if the parameterized type of the constructor is obvious from the context. For example, the following example does not compile:

    List<String> l = new ArrayList<>();
    l.add("A");
    l.addAll(new ArrayList<>());
    

    In comparison, the following example compiles:

    List<? extends String> list2 = new ArrayList<>();
    l.addAll(list2);
    
  4. Catching Multiple Exception Types and Rethrowing Exceptions with Improved Type Checking:

    In Java SE 7 and later, a single catch block can handle more than one type of exception. This feature can reduce code duplication. Consider the following code, which contains duplicate code in each of the catch blocks:

    catch (IOException e) {
        logger.log(e);
        throw e;
    }
    catch (SQLException e) {
        logger.log(e);
        throw e;
    }
    

    In releases prior to Java SE 7, it is difficult to create a common method to eliminate the duplicated code because the variable e has different types. The following example, which is valid in Java SE 7 and later, eliminates the duplicated code:

    catch (IOException|SQLException e) {
        logger.log(e);
        throw e;
    }
    

    The catch clause specifies the types of exceptions that the block can handle, and each exception type is separated with a vertical bar (|).

  5. The java.nio.file package

    The java.nio.file package and its related package, java.nio.file.attribute, provide comprehensive support for file I/O and for accessing the file system. A zip file system provider is also available in JDK 7.

Source: http://ohmjavaclasses.blogspot.com/

Postgresql query between date ranges

SELECT user_id 
FROM user_logs 
WHERE login_date BETWEEN '2014-02-01' AND '2014-03-01'

Between keyword works exceptionally for a date. it assumes the time is at 00:00:00 (i.e. midnight) for dates.

Write string to text file and ensure it always overwrites the existing content.

Generally, FileMode.Create is what you're looking for.

Enabling/installing GD extension? --without-gd

In CentOS (but the same may apply to other distros too) if you install the php7x-gd module followed by Apache restart and still the php -i does not show the GD Support => enabled it might mean that the php.ini was not automatically configured to support this extension.

All you have to to is either to edit the /etc/php/php.ini or to create a /etc/php.d/gd.ini file with the following content:

[gd]
extension=/path/to/gd.so # use the gd.so absolute path here

MySQL connection not working: 2002 No such file or directory

I encountered this problem too, then i modified 'localhost' to '127.0.0.1',it works.

OpenCV - DLL missing, but it's not?

You just need to add the folder of the needed dll file (or files) to your system "Environment Variables" in "Path". Your problem will 100% be resolved. I had this problem too.

Disable Tensorflow debugging information

I have had this problem as well (on tensorflow-0.10.0rc0), but could not fix the excessive nose tests logging problem via the suggested answers.

I managed to solve this by probing directly into the tensorflow logger. Not the most correct of fixes, but works great and only pollutes the test files which directly or indirectly import tensorflow:

# Place this before directly or indirectly importing tensorflow
import logging
logging.getLogger("tensorflow").setLevel(logging.WARNING)

Removing page title and date when printing web page (with CSS?)

Its simple. Just use css.

<style>
@page { size: auto;  margin: 0mm; }
</style>

Get length of array?

Try CountA:

Dim myArray(1 to 10) as String
Dim arrayCount as String
arrayCount = Application.CountA(myArray)
Debug.Print arrayCount

Azure SQL Database "DTU percentage" metric

A DTU is a unit of measure for the performance of a service tier and is a summary of several database characteristics. Each service tier has a certain number of DTUs assigned to it as an easy way to compare the performance level of one tier versus another.

Database Throughput Unit (DTU): DTUs provide a way to describe the relative capacity of a performance level of Basic, Standard, and Premium databases. DTUs are based on a blended measure of CPU, memory, reads, and writes. As DTUs increase, the power offered by the performance level increases. For example, a performance level with 5 DTUs has five times more power than a performance level with 1 DTU. A maximum DTU quota applies to each server.

The DTU Quota applies to the server, not the individual databases and each server has a maximum of 1600 DTUs. The DTU% is the percentage of units your particular database is using and it seems that this number can go over 100% of the DTU rating of the service tier (I assume to the limit of the server). This percentage number is designed to help you choose the appropriate service tier.

From down toward the bottom of this announcement:

For example, if your DTU consumption shows a value of 80%, it indicates it is consuming DTU at the rate of 80% of the limit an S2 database would have. If you see values greater than 100% in this view it means that you need a performance tier larger than S2.

As an example, let’s say you see a percentage value of 300%. This tells you that you are using three times more resources than would be available in an S2. To determine a reasonable starting size, compare the DTUs available in an S2 (50 DTUs) with the next higher sizes (P1 = 100 DTUs, or 200% of S2, P2 = 200 DTUs or 400% of S2). Because you are at 300% of S2 you would want to start with a P2 and re-test.

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

The biggest clue is the rows are all being returned on one line. This indicates line terminators are being ignored or are not present.

You can specify the line terminator for csv_reader. If you are on a mac the lines created will end with \rrather than the linux standard \n or better still the suspenders and belt approach of windows with \r\n.

pandas.read_csv(filename, sep='\t', lineterminator='\r')

You could also open all your data using the codecs package. This may increase robustness at the expense of document loading speed.

import codecs

doc = codecs.open('document','rU','UTF-16') #open for reading with "universal" type set

df = pandas.read_csv(doc, sep='\t')

Div with margin-left and width:100% overflowing on the right side

Add some css either in the head or in a external document. asp:TextBox are rendered as input :

input {
     width:100%;
}

Your html should look like : http://jsfiddle.net/c5WXA/

Note this will affect all your textbox : if you don't want this, give the containing div a class and specify the css.

.divClass input {
     width:100%;
}

how to find all indexes and their columns for tables, views and synonyms in oracle

Your query should work for synonyms as well as the tables. However, you seem to expect indexes on views where there are not. Maybe is it materialized views ?

What is the purpose of meshgrid in Python / NumPy?

meshgrid helps in creating a rectangular grid from two 1-D arrays of all pairs of points from the two arrays.

x = np.array([0, 1, 2, 3, 4])
y = np.array([0, 1, 2, 3, 4])

Now, if you have defined a function f(x,y) and you wanna apply this function to all the possible combination of points from the arrays 'x' and 'y', then you can do this:

f(*np.meshgrid(x, y))

Say, if your function just produces the product of two elements, then this is how a cartesian product can be achieved, efficiently for large arrays.

Referred from here

Loading context in Spring using web.xml

From the spring docs

Spring can be easily integrated into any Java-based web framework. All you need to do is to declare the ContextLoaderListener in your web.xml and use a contextConfigLocation to set which context files to load.

The <context-param>:

<context-param>
    <param-name>contextConfigLocation</param-name>
    <param-value>/WEB-INF/applicationContext*.xml</param-value>
</context-param>

<listener>
   <listener-class>
        org.springframework.web.context.ContextLoaderListener
   </listener-class>
</listener> 

You can then use the WebApplicationContext to get a handle on your beans.

WebApplicationContext ctx = WebApplicationContextUtils.getRequiredWebApplicationContext(servlet.getServletContext());
SomeBean someBean = (SomeBean) ctx.getBean("someBean");

See http://static.springsource.org/spring/docs/2.5.x/api/org/springframework/web/context/support/WebApplicationContextUtils.html for more info

Center an element in Bootstrap 4 Navbar

use mx-auto will do the job

<ul class="navbar-nav mx-auto">

Selecting and manipulating CSS pseudo-elements such as ::before and ::after using javascript (or jQuery)

IF you want to to manipulate the ::before or ::after sudo elements entirely through CSS, you could do it JS. See below;

jQuery('head').append('<style id="mystyle" type="text/css"> /* your styles here */ </style>');

Notice how the <style> element has an ID, which you can use to remove it and append to it again if your style changes dynamically.

This way, your element is style exactly how you want it through CSS, with the help of JS.

Can you animate a height change on a UITableViewCell when selected?

Yes It's Possible.

UITableView has a delegate method didSelectRowAtIndexPath

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
    [UIView animateWithDuration:.6
                          delay:0
         usingSpringWithDamping:UIViewAnimationOptionBeginFromCurrentState
          initialSpringVelocity:0
                        options:UIViewAnimationOptionBeginFromCurrentState animations:^{

                            cellindex = [NSIndexPath indexPathForRow:indexPath.row inSection:indexPath.section];
                            NSArray* indexArray = [NSArray arrayWithObjects:indexPath, nil];
                            [violatedTableView beginUpdates];
                            [violatedTableView reloadRowsAtIndexPaths:indexArray withRowAnimation:UITableViewRowAnimationAutomatic];
                            [violatedTableView endUpdates];
                        }
                     completion:^(BOOL finished) {
    }];
}

But in your case if the user scrolls and selects a different cell then u need to have the last selected cell to shrink and expand the currently selected cell reloadRowsAtIndexPaths: calls heightForRowAtIndexPath: so handle accordingly.

When to use LinkedList over ArrayList in Java?

It depends upon what operations you will be doing more on the List.

ArrayList is faster to access an indexed value. It is much worse when inserting or deleting objects.

To find out more, read any article that talks about the difference between arrays and linked lists.

How do you parse and process HTML/XML in PHP?

Advanced Html Dom is a simple HTML DOM replacement that offers the same interface, but it's DOM-based which means none of the associated memory issues occur.

It also has full CSS support, including jQuery extensions.

Reading Email using Pop3 in C#

downloading the email via the POP3 protocol is the easy part of the task. The protocol is quite simple and the only hard part could be advanced authentication methods if you don't want to send a clear text password over the network (and cannot use the SSL encrypted communication channel). See RFC 1939: Post Office Protocol - Version 3 and RFC 1734: POP3 AUTHentication command for details.

The hard part comes when you have to parse the received email, which means parsing MIME format in most cases. You can write quick&dirty MIME parser in a few hours or days and it will handle 95+% of all incoming messages. Improving the parser so it can parse almost any email means:

  • getting email samples sent from the most popular mail clients and improve the parser in order to fix errors and RFC misinterpretations generated by them.
  • Making sure that messages violating RFC for message headers and content will not crash your parser and that you will be able to read every readable or guessable value from the mangled email
  • correct handling of internationalization issues (e.g. languages written from righ to left, correct encoding for specific language etc)
  • UNICODE
  • Attachments and hierarchical message item tree as seen in "Mime torture email sample"
  • S/MIME (signed and encrypted emails).
  • and so on

Debugging a robust MIME parser takes months of work. I know, because I was watching my friend writing one such parser for the component mentioned below and was writing a few unit tests for it too ;-)

Back to the original question.

Following code taken from our POP3 Tutorial page and links would help you:

// 
// create client, connect and log in 
Pop3 client = new Pop3();
client.Connect("pop3.example.org");
client.Login("username", "password");

// get message list 
Pop3MessageCollection list = client.GetMessageList();

if (list.Count == 0)
{
    Console.WriteLine("There are no messages in the mailbox.");
}
else 
{
    // download the first message 
    MailMessage message = client.GetMailMessage(list[0].SequenceNumber);
    ...
}

client.Disconnect();

Excel Looping through rows and copy cell values to another worksheet

Private Sub CommandButton1_Click() 

Dim Z As Long 
Dim Cellidx As Range 
Dim NextRow As Long 
Dim Rng As Range 
Dim SrcWks As Worksheet 
Dim DataWks As Worksheet 
Z = 1 
Set SrcWks = Worksheets("Sheet1") 
Set DataWks = Worksheets("Sheet2") 
Set Rng = EntryWks.Range("B6:ad6") 

NextRow = DataWks.UsedRange.Rows.Count 
NextRow = IIf(NextRow = 1, 1, NextRow + 1) 

For Each RA In Rng.Areas 
    For Each Cellidx In RA 
        Z = Z + 1 
        DataWks.Cells(NextRow, Z) = Cellidx 
    Next Cellidx 
Next RA 
End Sub

Alternatively

Worksheets("Sheet2").Range("P2").Value = Worksheets("Sheet1").Range("L10") 

This is a CopynPaste - Method

Sub CopyDataToPlan()

Dim LDate As String
Dim LColumn As Integer
Dim LFound As Boolean

On Error GoTo Err_Execute

'Retrieve date value to search for
LDate = Sheets("Rolling Plan").Range("B4").Value

Sheets("Plan").Select

'Start at column B
LColumn = 2
LFound = False

While LFound = False

  'Encountered blank cell in row 2, terminate search
  If Len(Cells(2, LColumn)) = 0 Then
     MsgBox "No matching date was found."
     Exit Sub

  'Found match in row 2
  ElseIf Cells(2, LColumn) = LDate Then

     'Select values to copy from "Rolling Plan" sheet
     Sheets("Rolling Plan").Select
     Range("B5:H6").Select
     Selection.Copy

     'Paste onto "Plan" sheet
     Sheets("Plan").Select
     Cells(3, LColumn).Select
     Selection.PasteSpecial Paste:=xlValues, Operation:=xlNone, SkipBlanks:= _
     False, Transpose:=False

     LFound = True
     MsgBox "The data has been successfully copied."

     'Continue searching
      Else
         LColumn = LColumn + 1
      End If

   Wend

   Exit Sub

Err_Execute:
  MsgBox "An error occurred."

End Sub

And there might be some methods doing that in Excel.

How to change a single value in a NumPy array?

Is this what you are after? Just index the element and assign a new value.

A[2,1]=150

A
Out[345]: 
array([[ 1,  2,  3,  4],
       [ 5,  6,  7,  8],
       [ 9, 150, 11, 12],
       [13, 14, 15, 16]])

Renaming columns in Pandas

If you have to deal with loads of columns named by the providing system out of your control, I came up with the following approach that is a combination of a general approach and specific replacements in one go.

First create a dictionary from the dataframe column names using regular expressions in order to throw away certain appendixes of column names and then add specific replacements to the dictionary to name core columns as expected later in the receiving database.

This is then applied to the dataframe in one go.

dict = dict(zip(df.columns, df.columns.str.replace('(:S$|:C1$|:L$|:D$|\.Serial:L$)', '')))
dict['brand_timeseries:C1'] = 'BTS'
dict['respid:L'] = 'RespID'
dict['country:C1'] = 'CountryID'
dict['pim1:D'] = 'pim_actual'
df.rename(columns=dict, inplace=True)

How to get the primary IP address of the local machine on Linux and OS X?

ifconfig | grep 'inet ' | grep -v '127.0.0.1' | awk '{print $2}'

How to Allow Remote Access to PostgreSQL database

This is a complementary answer for the specific case of you using AWS cloud computing (either EC2 or RDS machines).

Besides doing everything proposed above, when using AWS cloud computing you will need to set you inbound rules in a way that let you access to the ports. Please check this post, which is valid for EC2 and RDS.

Reliable method to get machine's MAC address in C#

I really like AVee's solution with the lowest IP connection metric! But if a second nic with the same metric is installed, the MAC comparison could fail...

Better you store the description of the interface with the MAC. In later comparisons you can identify the right nic by this string. Here is a sample code:

   public static string GetMacAndDescription()
    {
        ManagementObjectSearcher searcher = new ManagementObjectSearcher("SELECT * FROM Win32_NetworkAdapterConfiguration where IPEnabled=true");
        IEnumerable<ManagementObject> objects = searcher.Get().Cast<ManagementObject>();
        string mac = (from o in objects orderby o["IPConnectionMetric"] select o["MACAddress"].ToString()).FirstOrDefault();
        string description = (from o in objects orderby o["IPConnectionMetric"] select o["Description"].ToString()).FirstOrDefault();
        return mac + ";" + description;
    }

    public static string GetMacByDescription( string description)
    {
        ManagementObjectSearcher searcher = new ManagementObjectSearcher("SELECT * FROM Win32_NetworkAdapterConfiguration where IPEnabled=true");
        IEnumerable<ManagementObject> objects = searcher.Get().Cast<ManagementObject>();
        string mac = (from o in objects where o["Description"].ToString() == description select o["MACAddress"].ToString()).FirstOrDefault();
        return mac;
    }

Twitter Bootstrap Modal Form Submit

Old, but maybe useful for readers to have a full example of how use modal.

I do like following ( working example jsfiddle ) :

$('button.btn.btn-success').click(function(event)
{

event.preventDefault();

$.post('getpostcodescript.php', $('form').serialize(), function(data, status, xhr)
    {
        // do something here with response;
        console.info(data);
        console.info(status);
        console.info(xhr);
    })
    .done(function() {
        // do something here if done ;
        alert( "saved" );
    })
    .fail(function() {
        // do something here if there is an error ;
        alert( "error" );
    })
    .always(function() {
        // maybe the good state to close the modal
        alert( "finished" );
        // Set a timeout to hide the element again
        setTimeout(function(){
          $("#myModal").hide();
        }, 3000);
    });
});

To deal easier with modals, I recommend using eModal, which permit to go faster on base use of bootstrap 3 modals.

Difference between left join and right join in SQL Server

Your two statements are equivalent.

Most people only use LEFT JOIN since it seems more intuitive, and it's universal syntax - I don't think all RDBMS support RIGHT JOIN.

Trim leading and trailing spaces from a string in awk

remove leading and trailing white space in 2nd column

awk 'BEGIN{FS=OFS=","}{gsub(/^[ \t]+/,"",$2);gsub(/[ \t]+$/,"",$2)}1' input.txt

another way by one gsub:

awk 'BEGIN{FS=OFS=","} {gsub(/^[ \t]+|[ \t]+$/, "", $2)}1' infile

In TensorFlow, what is the difference between Session.run() and Tensor.eval()?

Tensorflow 2.x Compatible Answer: Converting mrry's code to Tensorflow 2.x (>= 2.0) for the benefit of the community.

!pip install tensorflow==2.1
import tensorflow as tf

tf.compat.v1.disable_eager_execution()    

t = tf.constant(42.0)
sess = tf.compat.v1.Session()
with sess.as_default():   # or `with sess:` to close on exit
    assert sess is tf.compat.v1.get_default_session()
    assert t.eval() == sess.run(t)

#The most important difference is that you can use sess.run() to fetch the values of many tensors in the same step:

t = tf.constant(42.0)
u = tf.constant(37.0)
tu = tf.multiply(t, u)
ut = tf.multiply(u, t)
with sess.as_default():
   tu.eval()  # runs one step
   ut.eval()  # runs one step
   sess.run([tu, ut])  # evaluates both tensors in a single step

overlay two images in android to set an imageview

You can use the code below to solve the problem or download demo here

Create two functions to handle each.

First, the canvas is drawn and the images are drawn on top of each other from point (0,0)

On button click

public void buttonMerge(View view) {

        Bitmap bigImage = BitmapFactory.decodeResource(getResources(), R.drawable.img1);
        Bitmap smallImage = BitmapFactory.decodeResource(getResources(), R.drawable.img2);
        Bitmap mergedImages = createSingleImageFromMultipleImages(bigImage, smallImage);

        img.setImageBitmap(mergedImages);
    }

Function to create an overlay.

private Bitmap createSingleImageFromMultipleImages(Bitmap firstImage, Bitmap secondImage){

    Bitmap result = Bitmap.createBitmap(firstImage.getWidth(), firstImage.getHeight(), firstImage.getConfig());
    Canvas canvas = new Canvas(result);
    canvas.drawBitmap(firstImage, 0f, 0f, null);
    canvas.drawBitmap(secondImage, 10, 10, null);
    return result;
}

Read more

Dynamic SQL - EXEC(@SQL) versus EXEC SP_EXECUTESQL(@SQL)

The big thing about SP_EXECUTESQL is that it allows you to create parameterized queries which is very good if you care about SQL injection.

What's the environment variable for the path to the desktop?

KB's answer to use [Environment]::GetFolderPath("Desktop") is obviously the official Windows API for doing this.

However, if you're working interactively at the prompt, or just want something that works on your machine, the tilda (~) character refers to the current user's home folder. So ~/desktop is the user's desktop folder.

Merging 2 branches together in GIT

merge is used to bring two (or more) branches together.

a little example:

# on branch A:
# create new branch B
$ git checkout -b B
# hack hack
$ git commit -am "commit on branch B"

# create new branch C from A
$ git checkout -b C A
# hack hack
$ git commit -am "commit on branch C"

# go back to branch A
$ git checkout A
# hack hack
$ git commit -am "commit on branch A"

so now there are three separate branches (namely A B and C) with different heads

to get the changes from B and C back to A, checkout A (already done in this example) and then use the merge command:

# create an octopus merge
$ git merge B C

your history will then look something like this:

…-o-o-x-------A
      |\     /|
      | B---/ |
       \     /
        C---/

if you want to merge across repository/computer borders, have a look at git pull command, e.g. from the pc with branch A (this example will create two new commits):

# pull branch B
$ git pull ssh://host/… B
# pull branch C
$ git pull ssh://host/… C

Finding the Eclipse Version Number

(Update September 2012):

MRT points out in the comments that "Eclipse Version" question references a .eclipseproduct in the main folder, and it contains:

name=Eclipse Platform
id=org.eclipse.platform
version=3.x.0

So that seems more straightforward than my original answer below.

Also, Neeme Praks mentions below that there is a eclipse/configuration/config.ini which includes a line like:

eclipse.buildId=4.4.1.M20140925-0400

Again easier to find, as those are Java properties set and found with System.getProperty("eclipse.buildId").


Original answer (April 2009)

For Eclipse Helios 3.6, you can deduce the Eclipse Platform version directly from the About screen:
It is a combination of the Eclipse global version and the build Id:

alt text

Here is an example for Eclipse 3.6M6:
The version would be: 3.6.0.v201003121448, after the version 3.6.0 and the build Id I20100312-1448 (an Integration build from March 12th, 2010 at 14h48

To see it more easily, click on "Plugin Details" and sort by Version.


Note: Eclipse3.6 has a brand new cool logo:

alt text

And you can see the build Id now being displayed during the loading step of the different plugin.

What is Options +FollowSymLinks?

You might try searching the internet for ".htaccess Options not allowed here".

A suggestion I found (using google) is:

Check to make sure that your httpd.conf file has AllowOverride All.

A .htaccess file that works for me on Mint Linux (placed in the Laravel /public folder):

# Apache configuration file
# http://httpd.apache.org/docs/2.2/mod/quickreference.html

# Turning on the rewrite engine is necessary for the following rules and
# features. "+FollowSymLinks" must be enabled for this to work symbolically.

<IfModule mod_rewrite.c>
    Options +FollowSymLinks
    RewriteEngine On
</IfModule>

# For all files not found in the file system, reroute the request to the
# "index.php" front controller, keeping the query string intact

<IfModule mod_rewrite.c>
    RewriteCond %{REQUEST_FILENAME} !-f
    RewriteCond %{REQUEST_FILENAME} !-d
    RewriteRule ^(.*)$ index.php/$1 [L]
</IfModule>

Hope this helps you. Otherwise you could ask a question on the Laravel forum (http://forums.laravel.com/), there are some really helpful people hanging around there.

How to check string length and then select substring in Sql Server

To conditionally check the length of the string, use CASE.

SELECT  CASE WHEN LEN(comments) <= 60 
             THEN comments
             ELSE LEFT(comments, 60) + '...'
        END  As Comments
FROM    myView

How to return a string from a C++ function?

You never give any value to your strings in main so they are empty, and thus obviously the function returns an empty string.

Replace:

string str1, str2, str3;

with:

string str1 = "the dog jumped over the fence";
string str2 = "the";
string str3 = "that";

Also, you have several problems in your replaceSubstring function:

int index = s1.find(s2, 0);
s1.replace(index, s2.length(), s3);
  • std::string::find returns a std::string::size_type (aka. size_t) not an int. Two differences: size_t is unsigned, and it's not necessarily the same size as an int depending on your platform (eg. on 64 bits Linux or Windows size_t is unsigned 64 bits while int is signed 32 bits).
  • What happens if s2 is not part of s1? I'll leave it up to you to find how to fix that. Hint: std::string::npos ;)

Xamarin 2.0 vs Appcelerator Titanium vs PhoneGap

As an alternative you may want to check out BridgeIt at bridgeit.mobi. Open source, it has resolved the browser performance / consistency issue discussed above in that it leverages the standard browser on the device vs. the web-view browser. It also allows you to access the native features without having to worry about app store deployments and/or native containers.

I've used if for simple camera based access and scanner access and it works well for simple apps. Documentation is a bit light. Not sure how it would do on more complex apps.

A valid provisioning profile for this executable was not found... (again)

It happened to me when I accidentally left the build in release mode.

Which exception should I raise on bad/illegal argument combinations in Python?

I would inherit from ValueError

class IllegalArgumentError(ValueError):
    pass

It is sometimes better to create your own exceptions, but inherit from a built-in one, which is as close to what you want as possible.

If you need to catch that specific error, it is helpful to have a name.

Average of multiple columns

Select Req_ID, sum(R1+R2+R3+R4+R5)/5 as Average
from Request
Group by Req_ID;

Oracle - How to create a materialized view with FAST REFRESH and JOINS

To start with, from the Oracle Database Data Warehousing Guide:

Restrictions on Fast Refresh on Materialized Views with Joins Only

...

  • Rowids of all the tables in the FROM list must appear in the SELECT list of the query.

This means that your statement will need to look something like this:

CREATE MATERIALIZED VIEW MV_Test
  NOLOGGING
  CACHE
  BUILD IMMEDIATE 
  REFRESH FAST ON COMMIT 
  AS
    SELECT V.*, P.*, V.ROWID as V_ROWID, P.ROWID as P_ROWID 
    FROM TPM_PROJECTVERSION V,
         TPM_PROJECT P 
    WHERE P.PROJECTID = V.PROJECTID

Another key aspect to note is that your materialized view logs must be created as with rowid.

Below is a functional test scenario:

CREATE TABLE foo(foo NUMBER, CONSTRAINT foo_pk PRIMARY KEY(foo));

CREATE MATERIALIZED VIEW LOG ON foo WITH ROWID;

CREATE TABLE bar(foo NUMBER, bar NUMBER, CONSTRAINT bar_pk PRIMARY KEY(foo, bar));

CREATE MATERIALIZED VIEW LOG ON bar WITH ROWID;

CREATE MATERIALIZED VIEW foo_bar
  NOLOGGING
  CACHE
  BUILD IMMEDIATE
  REFRESH FAST ON COMMIT  AS SELECT foo.foo, 
                                    bar.bar, 
                                    foo.ROWID AS foo_rowid, 
                                    bar.ROWID AS bar_rowid 
                               FROM foo, bar
                              WHERE foo.foo = bar.foo;

What is the difference between $routeProvider and $stateProvider?

Angular's own ng-Router takes URLs into consideration while routing, UI-Router takes states in addition to URLs.

States are bound to named, nested and parallel views, allowing you to powerfully manage your application's interface.

While in ng-router, you have to be very careful about URLs when providing links via <a href=""> tag, in UI-Router you have to only keep state in mind. You provide links like <a ui-sref="">. Note that even if you use <a href=""> in UI-Router, just like you would do in ng-router, it will still work.

So, even if you decide to change your URL some day, your state will remain same and you need to change URL only at .config.

While ngRouter can be used to make simple apps, UI-Router makes development much easier for complex apps. Here its wiki.

Parsing JSON array into java.util.List with Gson

I read solution from official website of Gson at here

And this code for you:

    String json = "{"client":"127.0.0.1","servers":["8.8.8.8","8.8.4.4","156.154.70.1","156.154.71.1"]}";

    JsonObject jsonObject = new Gson().fromJson(json, JsonObject.class);
    JsonArray jsonArray = jsonObject.getAsJsonArray("servers");

    String[] arrName = new Gson().fromJson(jsonArray, String[].class);

    List<String> lstName = new ArrayList<>();
    lstName = Arrays.asList(arrName);

    for (String str : lstName) {
        System.out.println(str);
    }    

Result show on monitor:

8.8.8.8
8.8.4.4
156.154.70.1
156.154.71.1

How to change the version of the 'default gradle wrapper' in IntelliJ IDEA?

I was facing same issue for changing default gradle version from 5.0 to 4.7, Below are the steps to change default gradle version in intellij enter image description here
1) Change gradle version in gradle/wrapper/gradle-wrapper.properties in this property distributionUrl

2) Hit refresh button in gradle projects menu so that it will start downloading new gradle zip version

Window vs Page vs UserControl for WPF navigation?

A Window object is just what it sounds like: its a new Window for your application. You should use it when you want to pop up an entirely new window. I don't often use more than one Window in WPF because I prefer to put dynamic content in my main Window that changes based on user action.

A Page is a page inside your Window. It is mostly used for web-based systems like an XBAP, where you have a single browser window and different pages can be hosted in that window. It can also be used in Navigation Applications like sellmeadog said.

A UserControl is a reusable user-created control that you can add to your UI the same way you would add any other control. Usually I create a UserControl when I want to build in some custom functionality (for example, a CalendarControl), or when I have a large amount of related XAML code, such as a View when using the MVVM design pattern.

When navigating between windows, you could simply create a new Window object and show it

var NewWindow = new MyWindow();
newWindow.Show();

but like I said at the beginning of this answer, I prefer not to manage multiple windows if possible.

My preferred method of navigation is to create some dynamic content area using a ContentControl, and populate that with a UserControl containing whatever the current view is.

<Window x:Class="MyNamespace.MainWindow" ...>
    <DockPanel>
        <ContentControl x:Name="ContentArea" />
    </DockPanel>
</Window>

and in your navigate event you can simply set it using

ContentArea.Content = new MyUserControl();

But if you're working with WPF, I'd highly recommend the MVVM design pattern. I have a very basic example on my blog that illustrates how you'd navigate using MVVM, using this pattern:

<Window x:Class="SimpleMVVMExample.ApplicationView"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:local="clr-namespace:SimpleMVVMExample"
        Title="Simple MVVM Example" Height="350" Width="525">

   <Window.Resources>
      <DataTemplate DataType="{x:Type local:HomeViewModel}">
         <local:HomeView /> <!-- This is a UserControl -->
      </DataTemplate>
      <DataTemplate DataType="{x:Type local:ProductsViewModel}">
         <local:ProductsView /> <!-- This is a UserControl -->
      </DataTemplate>
   </Window.Resources>

   <DockPanel>
      <!-- Navigation Buttons -->
      <Border DockPanel.Dock="Left" BorderBrush="Black"
                                    BorderThickness="0,0,1,0">
         <ItemsControl ItemsSource="{Binding PageViewModels}">
            <ItemsControl.ItemTemplate>
               <DataTemplate>
                  <Button Content="{Binding Name}"
                          Command="{Binding DataContext.ChangePageCommand,
                             RelativeSource={RelativeSource AncestorType={x:Type Window}}}"
                          CommandParameter="{Binding }"
                          Margin="2,5"/>
               </DataTemplate>
            </ItemsControl.ItemTemplate>
         </ItemsControl>
      </Border>

      <!-- Content Area -->
      <ContentControl Content="{Binding CurrentPageViewModel}" />
   </DockPanel>
</Window>

Screenshot1 Screenshot2

How to change title of Activity in Android?

If you want to set title in Java file, then write in your activity onCreate

setTitle("Your Title");

if you want to in Manifest then write

    <activity
        android:name=".MainActivity"
        android:label="Your Title" >
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />

            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>

How to convert all tables in database to one collation?

Following on from G H I've added the user and host parameters incase you need to do this on a remote server

    #!/bin/bash

    # mycollate.sh <database> <user> <password> [<host> <charset> <collation>]
    # changes MySQL/MariaDB charset and collation for one database - all tables and
    # all columns in all tables

    DB="$1"
    USER="$2"
    PW="$3"
    HOST="$4"
    CHARSET="$5"
    COLL="$6"

    [ -n "$DB" ] || exit 1
    [ -n "$USER" ] || exit 1
    [ -n "$PW" ] || exit 1
    [ -n "$HOST" ] || HOST="localhost"
    [ -n "$CHARSET" ] || CHARSET="utf8mb4"
    [ -n "$COLL" ] || COLL="utf8mb4_general_ci"

    PW="--password=""$PW"
    HOST="--host=""$HOST"
    USER="--user=""$USER"

    echo $DB
    echo "ALTER DATABASE $DB CHARACTER SET $CHARSET COLLATE $COLL;" | mysql "$HOST" "$USER" "$PW"

    echo "USE $DB; SHOW TABLES;" | mysql  "$HOST" "$USER" "$PW" | (
        while read TABLE; do
            echo $DB.$TABLE
            echo "ALTER TABLE $TABLE CONVERT TO CHARACTER SET $CHARSET COLLATE $COLL;" | mysql  "$HOST" "$USER" "$PW" $DB
        done
    )

    PW="pleaseEmptyMeNow"

Python threading. How do I lock a thread?

You can see that your locks are pretty much working as you are using them, if you slow down the process and make them block a bit more. You had the right idea, where you surround critical pieces of code with the lock. Here is a small adjustment to your example to show you how each waits on the other to release the lock.

import threading
import time
import inspect

class Thread(threading.Thread):
    def __init__(self, t, *args):
        threading.Thread.__init__(self, target=t, args=args)
        self.start()

count = 0
lock = threading.Lock()

def incre():
    global count
    caller = inspect.getouterframes(inspect.currentframe())[1][3]
    print "Inside %s()" % caller
    print "Acquiring lock"
    with lock:
        print "Lock Acquired"
        count += 1  
        time.sleep(2)  

def bye():
    while count < 5:
        incre()

def hello_there():
    while count < 5:
        incre()

def main():    
    hello = Thread(hello_there)
    goodbye = Thread(bye)


if __name__ == '__main__':
    main()

Sample output:

...
Inside hello_there()
Acquiring lock
Lock Acquired
Inside bye()
Acquiring lock
Lock Acquired
...

How to implement a binary search tree in Python?

The following code is basic on @DTing‘s answer and what I learn from class, which uses a while loop to insert (indicated in the code).

class Node:
    def __init__(self, val):
        self.l_child = None
        self.r_child = None
        self.data = val


def binary_insert(root, node):
    y = None
    x = root
    z = node
    #while loop here
    while x is not None:
        y = x
        if z.data < x.data:
            x = x.l_child
        else:
            x = x.r_child
    z.parent = y
    if y == None:
        root = z
    elif z.data < y.data:
        y.l_child = z
    else:
        y.r_child = z


def in_order_print(root):
    if not root:
        return
    in_order_print(root.l_child)
    print(root.data)
    in_order_print(root.r_child)


r = Node(3)
binary_insert(r, Node(7))
binary_insert(r, Node(1))
binary_insert(r, Node(5))

in_order_print(r)

How to make Twitter Bootstrap tooltips have multiple lines?

If you're using Twitter Bootstrap Tooltip on non-link element, you can specify, that you want a multi-line tooltip directly in HTML code, without Javascript, using just the data parameter:

<span rel="tooltip" data-html="true" data-original-title="1<br />2<br />3">5</span>

This is just an alternative version of costales' answer. All the glory goes to him! :]

How to print in C

try this:

printf("%d", addNumber(a,b))

Here's the documentation for printf.

How can I get the timezone name in JavaScript?

Most upvoted answer is probably the best way to get the timezone, however, Intl.DateTimeFormat().resolvedOptions().timeZone returns IANA timezone name by definition, which is in English.

If you want the timezone's name in current user's language, you can parse it from Date's string representation like so:

_x000D_
_x000D_
function getTimezoneName() {_x000D_
  const today = new Date();_x000D_
  const short = today.toLocaleDateString(undefined);_x000D_
  const full = today.toLocaleDateString(undefined, { timeZoneName: 'long' });_x000D_
_x000D_
  // Trying to remove date from the string in a locale-agnostic way_x000D_
  const shortIndex = full.indexOf(short);_x000D_
  if (shortIndex >= 0) {_x000D_
    const trimmed = full.substring(0, shortIndex) + full.substring(shortIndex + short.length);_x000D_
    _x000D_
    // by this time `trimmed` should be the timezone's name with some punctuation -_x000D_
    // trim it from both sides_x000D_
    return trimmed.replace(/^[\s,.\-:;]+|[\s,.\-:;]+$/g, '');_x000D_
_x000D_
  } else {_x000D_
    // in some magic case when short representation of date is not present in the long one, just return the long one as a fallback, since it should contain the timezone's name_x000D_
    return full;_x000D_
  }_x000D_
}_x000D_
_x000D_
console.log(getTimezoneName());
_x000D_
_x000D_
_x000D_

Tested in Chrome and Firefox.

Ofcourse, this will not work as intended in some of the environments. For example, node.js returns a GMT offset (e.g. GMT+07:00) instead of a name. But I think it's still readable as a fallback.

P.S. Won't work in IE11, just as the Intl... solution.

Get text of label with jquery

Try:

<%=this.Label1.Text%>

Modify SVG fill color when being served as Background-Image

In some (very specific) situations this might be achieved by using a filter. For example, you can change a blue SVG image to purple by rotating the hue 45 degrees using filter: hue-rotate(45deg);. Browser support is minimal but it's still an interesting technique.

Demo

How to validate domain credentials?

Here's how to determine a local user:

    public bool IsLocalUser()
    {
        return windowsIdentity.AuthenticationType == "NTLM";
    }

Edit by Ian Boyd

You should not use NTLM anymore at all. It is so old, and so bad, that Microsoft's Application Verifier (which is used to catch common programming mistakes) will throw a warning if it detects you using NTLM.

Here's a chapter from the Application Verifier documentation about why they have a test if someone is mistakenly using NTLM:

Why the NTLM Plug-in is Needed

NTLM is an outdated authentication protocol with flaws that potentially compromise the security of applications and the operating system. The most important shortcoming is the lack of server authentication, which could allow an attacker to trick users into connecting to a spoofed server. As a corollary of missing server authentication, applications using NTLM can also be vulnerable to a type of attack known as a “reflection” attack. This latter allows an attacker to hijack a user’s authentication conversation to a legitimate server and use it to authenticate the attacker to the user’s computer. NTLM’s vulnerabilities and ways of exploiting them are the target of increasing research activity in the security community.

Although Kerberos has been available for many years many applications are still written to use NTLM only. This needlessly reduces the security of applications. Kerberos cannot however replace NTLM in all scenarios – principally those where a client needs to authenticate to systems that are not joined to a domain (a home network perhaps being the most common of these). The Negotiate security package allows a backwards-compatible compromise that uses Kerberos whenever possible and only reverts to NTLM when there is no other option. Switching code to use Negotiate instead of NTLM will significantly increase the security for our customers while introducing few or no application compatibilities. Negotiate by itself is not a silver bullet – there are cases where an attacker can force downgrade to NTLM but these are significantly more difficult to exploit. However, one immediate improvement is that applications written to use Negotiate correctly are automatically immune to NTLM reflection attacks.

By way of a final word of caution against use of NTLM: in future versions of Windows it will be possible to disable the use of NTLM at the operating system. If applications have a hard dependency on NTLM they will simply fail to authenticate when NTLM is disabled.

How the Plug-in Works

The Verifier plug detects the following errors:

  • The NTLM package is directly specified in the call to AcquireCredentialsHandle (or higher level wrapper API).

  • The target name in the call to InitializeSecurityContext is NULL.

  • The target name in the call to InitializeSecurityContext is not a properly-formed SPN, UPN or NetBIOS-style domain name.

The latter two cases will force Negotiate to fall back to NTLM either directly (the first case) or indirectly (the domain controller will return a “principal not found” error in the second case causing Negotiate to fall back).

The plug-in also logs warnings when it detects downgrades to NTLM; for example, when an SPN is not found by the Domain Controller. These are only logged as warnings since they are often legitimate cases – for example, when authenticating to a system that is not domain-joined.

NTLM Stops

5000 – Application Has Explicitly Selected NTLM Package

Severity – Error

The application or subsystem explicitly selects NTLM instead of Negotiate in the call to AcquireCredentialsHandle. Even though it may be possible for the client and server to authenticate using Kerberos this is prevented by the explicit selection of NTLM.

How to Fix this Error

The fix for this error is to select the Negotiate package in place of NTLM. How this is done will depend on the particular Network subsystem being used by the client or server. Some examples are given below. You should consult the documentation on the particular library or API set that you are using.

APIs(parameter) Used by Application    Incorrect Value  Correct Value  
=====================================  ===============  ========================
AcquireCredentialsHandle (pszPackage)  “NTLM”           NEGOSSP_NAME “Negotiate”

Way to create multiline comments in Bash?

Here's how I do multiline comments in bash.

This mechanism has two advantages that I appreciate. One is that comments can be nested. The other is that blocks can be enabled by simply commenting out the initiating line.

#!/bin/bash
# : <<'####.block.A'
echo "foo {" 1>&2
fn data1
echo "foo }" 1>&2
: <<'####.block.B'
fn data2 || exit
exit 1
####.block.B
echo "can't happen" 1>&2
####.block.A

In the example above the "B" block is commented out, but the parts of the "A" block that are not the "B" block are not commented out.

Running that example will produce this output:

foo {
./example: line 5: fn: command not found
foo }
can't happen

nginx - read custom header from upstream server

$http_name_of_the_header_key

i.e if you have origin = domain.com in header, you can use $http_origin to get "domain.com"

In nginx does support arbitrary request header field. In the above example last part of a variable name is the field name converted to lower case with dashes replaced by underscores

Reference doc here: http://nginx.org/en/docs/http/ngx_http_core_module.html#var_http_

For your example the variable would be $http_my_custom_header.

Making div content responsive

try this css:

/* Show in default resolution screen*/
#container2 {
width: 960px;
position: relative;
margin:0 auto;
line-height: 1.4em;
}

/* If in mobile screen with maximum width 479px. The iPhone screen resolution is 320x480 px (except iPhone4, 640x960) */    
@media only screen and (max-width: 479px){
    #container2 { width: 90%; }
}

Here the demo: http://jsfiddle.net/ongisnade/CG9WN/

Bootstrap with jQuery Validation Plugin

Adding onto Miguel Borges answer above you can give the user that green success feedback by adding the following line to in the highlight/unhighlight code block.

    highlight: function(element) {
        $(element).closest('.form-group').removeClass('has-success').addClass('has-error');
    },
    unhighlight: function(element) {
        $(element).closest('.form-group').removeClass('has-error').addClass('has-success');
    }

How do ACID and database transactions work?

ACID is a set of properties that you would like to apply when modifying a database.

  • Atomicity
  • Consistency
  • Isolation
  • Durability

A transaction is a set of related changes which is used to achieve some of the ACID properties. Transactions are tools to achieve the ACID properties.

Atomicity means that you can guarantee that all of a transaction happens, or none of it does; you can do complex operations as one single unit, all or nothing, and a crash, power failure, error, or anything else won't allow you to be in a state in which only some of the related changes have happened.

Consistency means that you guarantee that your data will be consistent; none of the constraints you have on related data will ever be violated.

Isolation means that one transaction cannot read data from another transaction that is not yet completed. If two transactions are executing concurrently, each one will see the world as if they were executing sequentially, and if one needs to read data that is written by another, it will have to wait until the other is finished.

Durability means that once a transaction is complete, it is guaranteed that all of the changes have been recorded to a durable medium (such as a hard disk), and the fact that the transaction has been completed is likewise recorded.

So, transactions are a mechanism for guaranteeing these properties; they are a way of grouping related actions together such that as a whole, a group of operations can be atomic, produce consistent results, be isolated from other operations, and be durably recorded.

Append text using StreamWriter

using(StreamWriter writer = new StreamWriter("debug.txt", true))
{
  writer.WriteLine("whatever you text is");
}

The second "true" parameter tells it to append.

http://msdn.microsoft.com/en-us/library/36b035cb.aspx

What is private bytes, virtual bytes, working set?

The definition of the perfmon counters has been broken since the beginning and for some reason appears to be too hard to correct.

A good overview of Windows memory management is available in the video "Mysteries of Memory Management Revealed" on MSDN: It covers more topics than needed to track memory leaks (eg working set management) but gives enough detail in the relevant topics.


To give you a hint of the problem with the perfmon counter descriptions, here is the inside story about private bytes from "Private Bytes Performance Counter -- Beware!" on MSDN:

Q: When is a Private Byte not a Private Byte?

A: When it isn't resident.

The Private Bytes counter reports the commit charge of the process. That is to say, the amount of space that has been allocated in the swap file to hold the contents of the private memory in the event that it is swapped out. Note: I'm avoiding the word "reserved" because of possible confusion with virtual memory in the reserved state which is not committed.


From "Performance Planning" on MSDN:

3.3 Private Bytes

3.3.1 Description

Private memory, is defined as memory allocated for a process which cannot be shared by other processes. This memory is more expensive than shared memory when multiple such processes execute on a machine. Private memory in (traditional) unmanaged dlls usually constitutes of C++ statics and is of the order of 5% of the total working set of the dll.

How to make an inline-block element fill the remainder of the line?

See: http://jsfiddle.net/qx32C/36/

_x000D_
_x000D_
.lineContainer {_x000D_
    overflow: hidden; /* clear the float */_x000D_
    border: 1px solid #000_x000D_
}_x000D_
.lineContainer div {_x000D_
    height: 20px_x000D_
} _x000D_
.left {_x000D_
    width: 100px;_x000D_
    float: left;_x000D_
    border-right: 1px solid #000_x000D_
}_x000D_
.right {_x000D_
    overflow: hidden;_x000D_
    background: #ccc_x000D_
}
_x000D_
<div class="lineContainer">_x000D_
    <div class="left">left</div>_x000D_
    <div class="right">right</div>_x000D_
</div>
_x000D_
_x000D_
_x000D_


Why did I replace margin-left: 100px with overflow: hidden on .right?

EDIT: Here are two mirrors for the above (dead) link:

How to change legend size with matplotlib.pyplot

plot.legend(loc = 'lower right', decimal_places = 2, fontsize = '11', title = 'Hey there', title_fontsize = '20')

matplotlib does not show my drawings although I call pyplot.show()

For me the problem happens if I simply create an empty matplotlibrc file under ~/.matplotlib on macOS. Adding "backend: macosx" in it fixes the problem.

I think it is a bug: if backend is not specified in my matplotlibrc it should take the default value.

Selecting pandas column by location

The method .transpose() converts columns to rows and rows to column, hence you could even write

df.transpose().ix[3]

How do relative file paths work in Eclipse?

Yeah, eclipse sees the top directory as the working/root directory, for the purposes of paths.

...just thought I'd add some extra info. I'm new here! I'd like to help.

How can I change NULL to 0 when getting a single value from a SQL function?

ORACLE/PLSQL:

NVL FUNCTION

SELECT NVL(SUM(Price), 0) AS TotalPrice 
FROM Inventory
WHERE (DateAdded BETWEEN @StartDate AND @EndDate)

This SQL statement would return 0 if the SUM(Price) returned a null value. Otherwise, it would return the SUM(Price) value.

How to delete projects in Intellij IDEA 14?

You will have to manually delete from the project explorer (your local machine hard drive), then delete the project in IntelliJ when it asks to re-open recent projects.

Find and replace entire mysql database

Another option (depending on the use case) would be to use DataMystic's TextPipe and DataPipe products. I've used them in the past, and they've worked great in the complex replacement scenarios, and without having to export data out of the database for find-and-replace.

How to sort a dataFrame in python pandas by two or more columns?

As of the 0.17.0 release, the sort method was deprecated in favor of sort_values. sort was completely removed in the 0.20.0 release. The arguments (and results) remain the same:

df.sort_values(['a', 'b'], ascending=[True, False])

You can use the ascending argument of sort:

df.sort(['a', 'b'], ascending=[True, False])

For example:

In [11]: df1 = pd.DataFrame(np.random.randint(1, 5, (10,2)), columns=['a','b'])

In [12]: df1.sort(['a', 'b'], ascending=[True, False])
Out[12]:
   a  b
2  1  4
7  1  3
1  1  2
3  1  2
4  3  2
6  4  4
0  4  3
9  4  3
5  4  1
8  4  1

As commented by @renadeen

Sort isn't in place by default! So you should assign result of the sort method to a variable or add inplace=True to method call.

that is, if you want to reuse df1 as a sorted DataFrame:

df1 = df1.sort(['a', 'b'], ascending=[True, False])

or

df1.sort(['a', 'b'], ascending=[True, False], inplace=True)

Capitalize the first letter of string in AngularJs

If you don't want to build custom filter then you can use directly

{{ foo.awesome_property.substring(0,1) | uppercase}}{{foo.awesome_property.substring(1)}}

how to check if string value is in the Enum list?

To parse the age:

Age age;
if (Enum.TryParse(typeof(Age), "New_Born", out age))
  MessageBox.Show("Defined");  // Defined for "New_Born, 1, 4 , 8, 12"

To see if it is defined:

if (Enum.IsDefined(typeof(Age), "New_Born"))
   MessageBox.Show("Defined");

Depending on how you plan to use the Age enum, flags may not be the right thing. As you probably know, [Flags] indicates you want to allow multiple values (as in a bit mask). IsDefined will return false for Age.Toddler | Age.Preschool because it has multiple values.

BadValue Invalid or no user locale set. Please ensure LANG and/or LC_* environment variables are set correctly

you have to add the missing local lang helper: for me the missing ones where de_LU de_LU.UTF-8 . Mongo 2.6.4 worked wihtout mongo 2.6.5 throw an error on this

Where is android_sdk_root? and how do I set it.?

MAC - one liner

echo "export ANDROID_HOME=~/Library/Android/sdk \
      export ANDROID_SDK_ROOT=~/Library/Android/sdk \
      export ANDROID_AVD_HOME=~/.android/avd" \
>> ~/.bash_profile && source ~/.bash_profile

ReactNative: how to center text?

From headline' style remove height, justifyContent and alignItems. It will center the text vertically. Add textAlign: 'center' and it will center the text horizontally.

  headline: {
    textAlign: 'center', // <-- the magic
    fontWeight: 'bold',
    fontSize: 18,
    marginTop: 0,
    width: 200,
    backgroundColor: 'yellow',
  }

How do I get my Python program to sleep for 50 milliseconds?

Note that if you rely on sleep taking exactly 50 ms, you won't get that. It will just be about it.

Compare data of two Excel Columns A & B, and show data of Column A that do not exist in B

Put this in C2 and copy down

=IF(ISNA(VLOOKUP(A2,$B$2:$B$65535,1,FALSE)),"not in B","")

Then if the value in A isn't in B the cell in column C will say "not in B".

jQuery DatePicker with today as maxDate

If you're using bootstrap 3 date time picker, try this:

$('.selector').datetimepicker({ maxDate: $.now() });

WPF User Control Parent

Different approaches and different strategies. In my case I could not find the window of my dialog either through using VisualTreeHelper or extension methods from Telerik to find parent of given type. Instead, I found my my dialog view which accepts custom injection of contents using Application.Current.Windows.

public Window GetCurrentWindowOfType<TWindowType>(){
 return Application.Current.Windows.OfType<TWindowType>().FirstOrDefault() as Window;
}

How to change package name of Android Project in Eclipse?

This is a bug in the Eclipse Android tools.

To fix: Right click on the project, go to Android tools -> Rename application package.

And also check AndroidManifest.xml if it updated correctly. In my case it didn't, and that should solve this problem.

Build android release apk on Phonegap 3.x CLI

just wondered around a lot because I got the same issue but in my installation the command "cordova" was never available and "phone gap build android --release" just ignored the platform/android/ant.properties.

so looking inside my platform filter I found a folder named "cordova" and inside of it there was an "build" binary that accepted the --release argument, it asked me for the key chains and I ended with a signed and ready for production APK.

this was never documented in any part of the phone gap site and frankly speaking now I kinda hate phonegap :( it was supposed to make the things easier but everything was just complicated :(

Free Rest API to retrieve current datetime as string (timezone irrelevant)

This API gives you the current time and several formats in JSON - https://market.mashape.com/parsify/format#time. Here's a sample response:

{
  "time": {
    "daysInMonth": 31,
    "millisecond": 283,
    "second": 42,
    "minute": 55,
    "hour": 1,
    "date": 6,
    "day": 3,
    "week": 10,
    "month": 2,
    "year": 2013,
    "zone": "+0000"
  },
  "formatted": {
    "weekday": "Wednesday",
    "month": "March",
    "ago": "a few seconds",
    "calendar": "Today at 1:55 AM",
    "generic": "2013-03-06T01:55:42+00:00",
    "time": "1:55 AM",
    "short": "03/06/2013",
    "slim": "3/6/2013",
    "hand": "Mar 6 2013",
    "handTime": "Mar 6 2013 1:55 AM",
    "longhand": "March 6 2013",
    "longhandTime": "March 6 2013 1:55 AM",
    "full": "Wednesday, March 6 2013 1:55 AM",
    "fullSlim": "Wed, Mar 6 2013 1:55 AM"
  },
  "array": [
    2013,
    2,
    6,
    1,
    55,
    42,
    283
  ],
  "offset": 1362534942283,
  "unix": 1362534942,
  "utc": "2013-03-06T01:55:42.283Z",
  "valid": true,
  "integer": false,
  "zone": 0
}

Heroku deployment error H10 (App crashed)

I know this question is very old. I add new answer just in case there is someone who has the same issue on Rails 3.

In my case, app started to crash on Heroku once "thin" gem was commented by accident on Gemfile.

It worked again I added back that gem.

use jQuery's find() on JSON object

The pure javascript solution is better, but a jQuery way would be to use the jQuery grep and/or map methods. Probably not much better than using $.each

jQuery.grep(TestObj, function(obj) {
    return obj.id === "A";
});

or

jQuery.map(TestObj, function(obj) {
    if(obj.id === "A")
         return obj; // or return obj.name, whatever.
});

Returns an array of the matching objects, or of the looked-up values in the case of map. Might be able to do what you want simply using those.

But in this example you'd have to do some recursion, because the data isn't a flat array, and we're accepting arbitrary structures, keys, and values, just like the pure javascript solutions do.

function getObjects(obj, key, val) {
    var retv = [];

    if(jQuery.isPlainObject(obj))
    {
        if(obj[key] === val) // may want to add obj.hasOwnProperty(key) here.
            retv.push(obj);

        var objects = jQuery.grep(obj, function(elem) {
            return (jQuery.isArray(elem) || jQuery.isPlainObject(elem));
        });

        retv.concat(jQuery.map(objects, function(elem){
            return getObjects(elem, key, val);
        }));
    }

    return retv;
}

Essentially the same as Box9's answer, but using the jQuery utility functions where useful.

········

Allowing Java to use an untrusted certificate for SSL/HTTPS connection

Here is some relevant code:

// Create a trust manager that does not validate certificate chains
TrustManager[] trustAllCerts = new TrustManager[]{
    new X509TrustManager() {
        public java.security.cert.X509Certificate[] getAcceptedIssuers() {
            return null;
        }
        public void checkClientTrusted(
            java.security.cert.X509Certificate[] certs, String authType) {
        }
        public void checkServerTrusted(
            java.security.cert.X509Certificate[] certs, String authType) {
        }
    }
};

// Install the all-trusting trust manager
try {
    SSLContext sc = SSLContext.getInstance("SSL");
    sc.init(null, trustAllCerts, new java.security.SecureRandom());
    HttpsURLConnection.setDefaultSSLSocketFactory(sc.getSocketFactory());
} catch (Exception e) {
}

// Now you can access an https URL without having the certificate in the truststore
try {
    URL url = new URL("https://hostname/index.html");
} catch (MalformedURLException e) {
}

This will completely disable SSL checking—just don't learn exception handling from such code!

To do what you want, you would have to implement a check in your TrustManager that prompts the user.

Error parsing yaml file: mapping values are not allowed here

Maybe this will help someone else, but I've seen this error when the RHS of the mapping contains a colon without enclosing quotes, such as:

someKey: another key: Change to make today: work out more

should be

someKey: another key: "Change to make today: work out more"

Evenly distributing n points on a sphere

Healpix solves a closely related problem (pixelating the sphere with equal area pixels):

http://healpix.sourceforge.net/

It's probably overkill, but maybe after looking at it you'll realize some of it's other nice properties are interesting to you. It's way more than just a function that outputs a point cloud.

I landed here trying to find it again; the name "healpix" doesn't exactly evoke spheres...

How to create an email form that can send email using html

you can use Simple Contact Form in HTML with PHP mailer. It's easy to implement in you website. You can try the demo from following link: Simple Contact/Feedback Form in HTML-PHP mailer

Otherwise you can watch the demo video in following link: Youtube: Simple Contact/Feedback Form in HTML-PHP mailer

When you are running in localhost, you may get following error:

Warning: mail(): Failed to connect to mailserver at "smtp.gmail.com" port 25, verify your "SMTP" and "smtp_port" setting in php.ini or use ini_set() in S:\wamp\www\sample\mailTo.php on line 10

You can check in this link for more detailed information: Simple Contact/Feedback Form in HTML with php (HTML-PHP mailer) And this is the screenshot of HTML form: Simple Form

And this is the main PHP coding:

<?php
if($_POST["submit"]) {
    $recipient="[email protected]"; //Enter your mail address
    $subject="Contact from Website"; //Subject 
    $sender=$_POST["name"];
    $senderEmail=$_POST["email"];
    $message=$_POST["comments"];
    $mailBody="Name: $sender\nEmail Address: $senderEmail\n\nMessage: $message";
    mail($recipient, $subject, $mailBody);
    sleep(1);
    header("Location:http://blog.antonyraphel.in/sample/"); // Set here redirect page or destination page
}
?>

Javascript getElementById based on a partial string

I'm not entirely sure I know what you're asking about, but you can use string functions to create the actual ID that you're looking for.

var base = "common";
var num = 3;

var o = document.getElementById(base + num);  // will find id="common3"

If you don't know the actual ID, then you can't look up the object with getElementById, you'd have to find it some other way (by class name, by tag type, by attribute, by parent, by child, etc...).

Now that you've finally given us some of the HTML, you could use this plain JS to find all form elements that have an ID that starts with "poll-":

// get a list of all form objects that have the right type of ID
function findPollForms() {
    var list = getElementsByTagName("form");
    var results = [];
    for (var i = 0; i < list.length; i++) {
        var id = list[i].id;
        if (id && id.search(/^poll-/) != -1) {
            results.push(list[i]);
        }
    }
    return(results);
}

// return the ID of the first form object that has the right type of ID
function findFirstPollFormID() {
    var list = getElementsByTagName("form");
    var results = [];
    for (var i = 0; i < list.length; i++) {
        var id = list[i].id;
        if (id && id.search(/^poll-/) != -1) {
            return(id);
        }
    }
    return(null);
}

Wheel file installation

If you already have a wheel file (.whl) on your pc, then just go with the following code:

cd ../user
pip install file.whl

If you want to download a file from web, and then install it, go with the following in command line:

pip install package_name

or, if you have the url:

pip install http//websiteurl.com/filename.whl

This will for sure install the required file.

Note: I had to type pip2 instead of pip while using Python 2.

Programmatically register a broadcast receiver

Create a broadcast receiver

[BroadcastReceiver(Enabled = true, Exported = false)]

public class BCReceiver : BroadcastReceiver
{

    BCReceiver receiver;

    public override void OnReceive(Context context, Intent intent)
    {
        //Do something here
    }
}

From your activity add this code:

LocalBroadcastManager.getInstance(ApplicationContext)
    .registerReceiver(receiver, filter);

Refresh Page and Keep Scroll Position

document.location.reload() stores the position, see in the docs.

Add additional true parameter to force reload, but without restoring the position.

document.location.reload(true)

MDN docs:

The forcedReload flag changes how some browsers handle the user's scroll position. Usually reload() restores the scroll position afterward, but forced mode can scroll back to the top of the page, as if window.scrollY === 0.

How can I get onclick event on webview in android?

Hamidreza's solution almost worked for me.

I noticed from experimentation that a simple tap usually has 2-5 action move events. Checking the time between action down and up was simpler and behaved more like what I expected.

private class CheckForClickTouchLister implements View.OnTouchListener {
    private final static long MAX_TOUCH_DURATION = 100;

    @Override
    public boolean onTouch(View v, MotionEvent event) {

        switch (event.getAction()) {

            case MotionEvent.ACTION_DOWN:
                m_DownTime = event.getEventTime(); //init time

                break;

            case MotionEvent.ACTION_UP:
                if(event.getEventTime() - m_DownTime <= MAX_TOUCH_DURATION)
                    //On click action

                break;

            default:
                break; //No-Op

        }
        return false;
    }

What does an exclamation mark before a cell reference mean?

When entered as the reference of a Named range, it refers to range on the sheet the named range is used on.

For example, create a named range MyName refering to =SUM(!B1:!K1)

Place a formula on Sheet1 =MyName. This will sum Sheet1!B1:K1

Now place the same formula (=MyName) on Sheet2. That formula will sum Sheet2!B1:K1

Note: (as pnuts commented) this and the regular SheetName!B1:K1 format are relative, so reference different cells as the =MyName formula is entered into different cells.

Is it possible to read the value of a annotation in java?

You can also use generic types, in my case, taking into account everything said before you can do something like:

public class SomeTypeManager<T> {

    public SomeTypeManager(T someGeneric) {

        //That's how you can achieve all previously said, with generic types.
        Annotation[] an = someGeneric.getClass().getAnnotations();

    }

}

Remember, that this will not equival at 100% to SomeClass.class.get(...)();

But can do the trick...

SQL Query for Logins

Is this what you're after?

select * from master.syslogins

Different color for each bar in a bar chart; ChartJS

try this :

  function getChartJs() {
        **var dynamicColors = function () {
            var r = Math.floor(Math.random() * 255);
            var g = Math.floor(Math.random() * 255);
            var b = Math.floor(Math.random() * 255);
            return "rgb(" + r + "," + g + "," + b + ")";
        }**

        $.ajax({
            type: "POST",
            url: "ADMIN_DEFAULT.aspx/GetChartByJenisKerusakan",
            data: "{}",
            contentType: "application/json; charset=utf-8",
            dataType: "json",
            success: function (r) {
                var labels = r.d[0];
                var series1 = r.d[1];
                var data = {
                    labels: r.d[0],
                    datasets: [
                        {
                            label: "My First dataset",
                            data: series1,
                            strokeColor: "#77a8a8",
                            pointColor: "#eca1a6"
                        }
                    ]
                };

                var ctx = $("#bar_chart").get(0).getContext('2d');
                ctx.canvas.height = 300;
                ctx.canvas.width = 500;
                var lineChart = new Chart(ctx).Bar(data, {
                    bezierCurve: false,
                    title:
                      {
                          display: true,
                          text: "ProductWise Sales Count"
                      },
                    responsive: true,
                    maintainAspectRatio: true
                });

                $.each(r.d, function (key, value) {
                    **lineChart.datasets[0].bars[key].fillColor = dynamicColors();
                    lineChart.datasets[0].bars[key].fillColor = dynamicColors();**
                    lineChart.update();
                });
            },
            failure: function (r) {
                alert(r.d);
            },
            error: function (r) {
                alert(r.d);
            }
        });
    }

Getting the count of unique values in a column in bash

Ruby(1.9+)

#!/usr/bin/env ruby
Dir["*"].each do |file|
    h=Hash.new(0)
    open(file).each do |row|
        row.chomp.split("\t").each do |w|
            h[ w ] += 1
        end
    end
    h.sort{|a,b| b[1]<=>a[1] }.each{|x,y| print "#{x}:#{y}\n" }
end

When and how should I use a ThreadLocal variable?

Since a ThreadLocal is a reference to data within a given Thread, you can end up with classloading leaks when using ThreadLocals in application servers using thread pools. You need to be very careful about cleaning up any ThreadLocals you get() or set() by using the ThreadLocal's remove() method.

If you do not clean up when you're done, any references it holds to classes loaded as part of a deployed webapp will remain in the permanent heap and will never get garbage collected. Redeploying/undeploying the webapp will not clean up each Thread's reference to your webapp's class(es) since the Thread is not something owned by your webapp. Each successive deployment will create a new instance of the class which will never be garbage collected.

You will end up with out of memory exceptions due to java.lang.OutOfMemoryError: PermGen space and after some googling will probably just increase -XX:MaxPermSize instead of fixing the bug.

If you do end up experiencing these problems, you can determine which thread and class is retaining these references by using Eclipse's Memory Analyzer and/or by following Frank Kieviet's guide and followup.

Update: Re-discovered Alex Vasseur's blog entry that helped me track down some ThreadLocal issues I was having.

Could not create work tree dir 'example.com'.: Permission denied

I was facing same issue then I read first few lines of this question and I realised that I was trying to run command at the root directory of my bash profile instead of CD/my work project folder. I switched back to my work folder and able to clone the project successfully

Preloading @font-face fonts?

As I found the best way is doing is preloading a stylesheet that contains the font face, and then let browser to load it automatically. I used the font-face in other locations (in the html page), but then I could observe the font changing effect briefly.

<link href="fonts.css?family=Open+Sans" rel="preload stylesheet" as="style">

then in the font.css file, specify as following.

@font-face {
  font-family: 'Open Sans';
  font-style: normal;
  font-weight: 400;
  src: local('Open Sans Regular'), local('OpenSans-Regular'),
       url('open-sans-v16-latin-regular.woff2') format('woff2'); /*  Super Modern Browsers */
}

You can't assign a name to fonts when it's preloaded through link tag (correct me if I was wrong I couldn't find a way yet), and thus you have to use font-face to assign the name to the font. Even though it's possible to load a font through link tag, it's not recommended as you can't assign a name to the font with it. Without a name as with font-face, you won't be able to use it anywhere in the web page. According to gtmetrix, style sheet loads at the beginning, then rest of the scripts/style by order, then the font before dom is loaded, and therefore you don't see font changing effect.

Disable/enable an input with jQuery?

jQuery 1.6+

To change the disabled property you should use the .prop() function.

$("input").prop('disabled', true);
$("input").prop('disabled', false);

jQuery 1.5 and below

The .prop() function doesn't exist, but .attr() does similar:

Set the disabled attribute.

$("input").attr('disabled','disabled');

To enable again, the proper method is to use .removeAttr()

$("input").removeAttr('disabled');

In any version of jQuery

You can always rely on the actual DOM object and is probably a little faster than the other two options if you are only dealing with one element:

// assuming an event handler thus 'this'
this.disabled = true;

The advantage to using the .prop() or .attr() methods is that you can set the property for a bunch of selected items.


Note: In 1.6 there is a .removeProp() method that sounds a lot like removeAttr(), but it SHOULD NOT BE USED on native properties like 'disabled' Excerpt from the documentation:

Note: Do not use this method to remove native properties such as checked, disabled, or selected. This will remove the property completely and, once removed, cannot be added again to element. Use .prop() to set these properties to false instead.

In fact, I doubt there are many legitimate uses for this method, boolean props are done in such a way that you should set them to false instead of "removing" them like their "attribute" counterparts in 1.5

SQL Server FOR EACH Loop

SQL is primarily a set-orientated language - it's generally a bad idea to use a loop in it.

In this case, a similar result could be achieved using a recursive CTE:

with cte as
(select 1 i union all
 select i+1 i from cte where i < 5)
select dateadd(d, i-1, '2010-01-01') from cte

Laravel - Route::resource vs Route::controller

For route controller method we have to define only one route. In get or post method we have to define the route separately.

And the resources method is used to creates multiple routes to handle a variety of Restful actions.

Here the Laravel documentation about this.

When to use @QueryParam vs @PathParam

You can support both query parameters and path parameters, e.g., in the case of aggregation of resources -- when the collection of sub-resources makes sense on its own.

/departments/{id}/employees
/employees?dept=id

Query parameters can support hierarchical and non-hierarchical subsetting; path parameters are hierarchical only.

Resources can exhibit multiple hierarchies. Support short paths if you will be querying broad sub-collections that cross hierarchical boundaries.

/inventory?make=toyota&model=corolla
/inventory?year=2014

Use query parameters to combine orthogonal hierarchies.

/inventory/makes/toyota/models/corolla?year=2014
/inventory/years/2014?make=toyota&model=corolla
/inventory?make=toyota&model=corolla&year=2014

Use only path parameters in the case of composition -- when a resource doesn't make sense divorced from its parent, and the global collection of all children is not a useful resource in itself.

/words/{id}/definitions
/definitions?word=id   // not useful

How is a tag different from a branch in Git? Which should I use, here?

Tags can be either signed or unsigned; branches are never signed.

Signed tags can never move because they are cryptographically bound (with a signature) to a particular commit. Unsigned tags are not bound and it is possible to move them (but moving tags is not a normal use case).

Branches can not only move to a different commit but are expected to do so. You should use a branch for your local development project. It doesn't quite make sense to commit work to a Git repository "on a tag".

Page redirect with successful Ajax request

I think you can do that with:

window.location = "your_url";

Understanding the Gemfile.lock file

What does the exclamation mark after the gem name in the 'DEPENDECIES' group mean?

The exclamation mark appears when the gem was installed using a source other than "https://rubygems.org".

What is the T-SQL syntax to connect to another SQL Server?

If possible, check out SSIS (SQL Server Integration Services). I am just getting my feet wet with this toolkit, but already am looping over 40+ servers and preparing to wreak all kinds of havoc ;)

How to dynamically update labels captions in VBA form?

If you want to use this in VBA:

For i = 1 To X
    UserForm1.Controls("Label" & i).Caption =  MySheet.Cells(i + 1, i).Value
Next

How to implement authenticated routes in React Router 4?

You're going to want to use the Redirect component. There's a few different approaches to this problem. Here's one I like, have a PrivateRoute component that takes in an authed prop and then renders based on that props.

function PrivateRoute ({component: Component, authed, ...rest}) {
  return (
    <Route
      {...rest}
      render={(props) => authed === true
        ? <Component {...props} />
        : <Redirect to={{pathname: '/login', state: {from: props.location}}} />}
    />
  )
}

Now your Routes can look something like this

<Route path='/' exact component={Home} />
<Route path='/login' component={Login} />
<Route path='/register' component={Register} />
<PrivateRoute authed={this.state.authed} path='/dashboard' component={Dashboard} />

If you're still confused, I wrote this post that may help - Protected routes and authentication with React Router v4

Jquery-How to grey out the background while showing the loading icon over it

1) "container" is a class and not an ID 2) .container - set z-index and display: none in your CSS and not inline unless there is a really good reason to do so. Demo@fiddle

$("#button").click(function() {
    $(".container").css("opacity", 0.2);
   $("#loading-img").css({"display": "block"});
});

CSS:

#loading-img {
    background: url(http://web.bogdanteodoru.com/wp-content/uploads/2012/01/bouncy-css3-loading-animation.jpg) center center no-repeat;  /* different for testing purposes */
    display: none;
    height: 100px; /* for testing purposes */
    z-index: 12;
}

And a demo with animated image.

SQL Server: Importing database from .mdf?

To perform this operation see the next images:

enter image description here

and next step is add *.mdf file,

very important, the .mdf file must be located in C:......\MSSQL12.SQLEXPRESS\MSSQL\DATA

enter image description here

Now remove the log file

enter image description here

How do I make an auto increment integer field in Django?

In django with every model you will get the by default id field that is auto increament. But still if you manually want to use auto increment. You just need to specify in your Model AutoField.

class Author(models.Model):
    author_id = models.AutoField(primary_key=True)

you can read more about the auto field in django in Django Documentation for AutoField

What port number does SOAP use?

SOAP (Simple Object Access Protocol) is the communication protocol in the web service scenario.

One benefit of SOAP is that it allowas RPC to execute through a firewall. But to pass through a firewall, you will probably want to use 80. it uses port no.8084 To the firewall, a SOAP conversation on 80 looks like a POST to a web page. However, there are extensions in SOAP which are specifically aimed at the firewall. In the future, it may be that firewalls will be configured to filter SOAP messages. But as of today, most firewalls are SOAP ignorant.

so exclusively open SOAP Port in Firewalls

Get value of input field inside an iframe

Yes it should be possible, even if the site is from another domain.

For example, in an HTML page on my site I have an iFrame whose contents are sourced from another website. The iFrame content is a single select field.

I need to be able to read the selected value on my site. In other words, I need to use the select list from another domain inside my own application. I do not have control over any server settings.

Initially therefore we might be tempted to do something like this (simplified):

HTML in my site:

<iframe name='select_frame' src='http://www.othersite.com/select.php?initial_name=jim'></iframe>
<input type='button' name='save' value='SAVE'>

HTML contents of iFrame (loaded from select.php on another domain):

<select id='select_name'>
    <option value='john'>John</option>
    <option value='jim' selected>Jim</option>
</select>

jQuery:

$('input:button[name=save]').click(function() {
    var name = $('iframe[name=select_frame]').contents().find('#select_name').val();
});

However, I receive this javascript error when I attempt to read the value:

Blocked a frame with origin "http://www.myownsite.com" from accessing a frame with origin "http://www.othersite.com". Protocols, domains, and ports must match.

To get around this problem, it seems that you can indirectly source the iFrame from a script in your own site, and have that script read the contents from the other site using a method like file_get_contents() or curl etc.

So, create a script (for example: select_local.php in the current directory) on your own site with contents similar to this:

PHP content of select_local.php:

<?php
    $url = "http://www.othersite.com/select.php?" . $_SERVER['QUERY_STRING'];
    $html_select = file_get_contents($url);
    echo $html_select;
?>

Also modify the HTML to call this local (instead of the remote) script:

<iframe name='select_frame' src='select_local.php?initial_name=jim'></iframe>
<input type='button' name='save' value='SAVE'>

Now your browser should think that it is loading the iFrame content from the same domain.

Using VBA code, how to export Excel worksheets as image in Excel 2003?

This gives me the most reliable results:

Sub RangeToPicture()
  Dim FileName As String: FileName = "C:\file.bmp"
  Dim rPrt As Range: Set rPrt = ThisWorkbook.Sheets("Sheet1").Range("A1:C6")

  Dim chtObj As ChartObject
  rPrt.CopyPicture xlScreen, xlBitmap
  Set chtObj = ActiveSheet.ChartObjects.Add(1, 1, rPrt.Width, rPrt.Height)
  chtObj.Activate
  ActiveChart.Paste
  ActiveChart.Export FileName
  chtObj.Delete
End Sub

What are the different NameID format used for?

About this I think you can reference to http://docs.oasis-open.org/security/saml/Post2.0/sstc-saml-tech-overview-2.0.html.

Here're my understandings about this, with the Identity Federation Use Case to give a details for those concepts:

  • Persistent identifiers-

IdP provides the Persistent identifiers, they are used for linking to the local accounts in SPs, but they identify as the user profile for the specific service each alone. For example, the persistent identifiers are kind of like : johnForAir, jonhForCar, johnForHotel, they all just for one specified service, since it need to link to its local identity in the service.

  • Transient identifiers-

Transient identifiers are what IdP tell the SP that the users in the session have been granted to access the resource on SP, but the identities of users do not offer to SP actually. For example, The assertion just like “Anonymity(Idp doesn’t tell SP who he is) has the permission to access /resource on SP”. SP got it and let browser to access it, but still don’t know Anonymity' real name.

  • unspecified identifiers-

The explanation for it in the spec is "The interpretation of the content of the element is left to individual implementations". Which means IdP defines the real format for it, and it assumes that SP knows how to parse the format data respond from IdP. For example, IdP gives a format data "UserName=XXXXX Country=US", SP get the assertion, and can parse it and extract the UserName is "XXXXX".

Bad Request - Invalid Hostname IIS7

For Visual Studio 2017 and Visual Studio 2015, IIS Express settings is stored in the hidden .vs directory and the path is something like this .vs\config\applicationhost.config, add binding like below will work

<bindings>
    <binding protocol="http" bindingInformation="*:8802:localhost" />
    <binding protocol="http" bindingInformation="*:8802:127.0.0.1" />
</bindings>

Syntax: https://docs.microsoft.com/en-us/dotnet/api/microsoft.web.administration.binding.bindinginformation?view=iis-dotnet

Replace part of a string in Python?

Use the replace() method on string:

>>> stuff = "Big and small"
>>> stuff.replace( " and ", "/" )
'Big/small'

How to print a date in a regular format?

You can use easy_date to make it easy:

import date_converter
my_date = date_converter.date_to_string(today, '%Y-%m-%d')

PHP Composer behind http proxy

If you are using Windows, you should set the same environment variables, but Windows style:

set http_proxy=<your_http_proxy:proxy_port>
set https_proxy=<your_https_proxy:proxy_port>

That will work for your current cmd.exe. If you want to do this more permanent, y suggest you to use environment variables on your system.

Check if table exists without using "select from"

Rather than relying on errors, you can query INFORMATION_SCHEMA.TABLES to see if the table exists. If there's a record, it exists. If there's no record, it doesn't exist.

How can I use Async with ForEach?

I would like to add that there is a Parallel class with ForEach function built in that can be used for this purpose.

Getting attributes of a class

If you want to "get" an attribute, there is a very simple answer, which should be obvious: getattr

class MyClass(object):
a = '12'
b = '34'
def myfunc(self):
    return self.a

>>> getattr(MyClass, 'a')
'12'

>>> getattr(MyClass, 'myfunc')
<function MyClass.myfunc at 0x10de45378>

It works dandy both in Python 2.7 and Python 3.x.

If you want a list of these items, you will still need to use inspect.

Getting net::ERR_UNKNOWN_URL_SCHEME while calling telephone number from HTML page in Android

I had this issue occurring with mailto: and tel: links inside an iframe (in Chrome, not a webview). Clicking the links would show the grey "page not found" page and inspecting the page showed it had a ERR_UNKNOWN_URL_SCHEME error.

Adding target="_blank", as suggested by this discussion of the issue fixed the problem for me.

How to find the logs on android studio?

On a Mac, the idea.log is contained in

/Users/<user>/Library/Logs/AndroidStudio/idea.log

The new stable version (1.2) is in

/Users/<user>/Library/Logs/AndroidStudio1.2/

The new stable version (2.2) is in

/Users/<user>/Library/Logs/AndroidStudio2.2/

The new stable version (3.4) is in

/Users/<user>/Library/Logs/AndroidStudio3.4/

How to download a file from a website in C#

You can use this code to Download file from a WebSite to Desktop:

using System.Net;

WebClient client = new WebClient ();
client.DownloadFileAsync(new Uri("http://www.Address.com/File.zip"), Environment.GetFolderPath(Environment.SpecialFolder.Desktop) + "File.zip");

How to format current time using a yyyyMMddHHmmss format?

Use

fmt.Println(t.Format("20060102150405"))

as Go uses following constants to format date,refer here

const (
    stdLongMonth      = "January"
    stdMonth          = "Jan"
    stdNumMonth       = "1"
    stdZeroMonth      = "01"
    stdLongWeekDay    = "Monday"
    stdWeekDay        = "Mon"
    stdDay            = "2"
    stdUnderDay       = "_2"
    stdZeroDay        = "02"
    stdHour           = "15"
    stdHour12         = "3"
    stdZeroHour12     = "03"
    stdMinute         = "4"
    stdZeroMinute     = "04"
    stdSecond         = "5"
    stdZeroSecond     = "05"
    stdLongYear       = "2006"
    stdYear           = "06"
    stdPM             = "PM"
    stdpm             = "pm"
    stdTZ             = "MST"
    stdISO8601TZ      = "Z0700"  // prints Z for UTC
    stdISO8601ColonTZ = "Z07:00" // prints Z for UTC
    stdNumTZ          = "-0700"  // always numeric
    stdNumShortTZ     = "-07"    // always numeric
    stdNumColonTZ     = "-07:00" // always numeric
)

How do I create my own URL protocol? (e.g. so://...)

A Protocol?

I found this, it appears to be a local setting for a computer...

http://kb.mozillazine.org/Register_protocol

sqlplus error on select from external table: ORA-29913: error in executing ODCIEXTTABLEOPEN callout

We faced the same problem:

ORA-29913: error in executing ODCIEXTTABLEOPEN callout
ORA-29400: data cartridge error error opening file /fs01/app/rms01/external/logs/SH_EXT_TAB_VGAG_DELIV_SCHED.log

In our case we had a RAC with 2 nodes. After giving write permission on the log directory, on both sides, everything worked fine.

What is the Python equivalent of Matlab's tic and toc functions?

This can also be done using a wrapper. Very general way of keeping time.

The wrapper in this example code wraps any function and prints the amount of time needed to execute the function:

def timethis(f):
    import time

    def wrapped(*args, **kwargs):
        start = time.time()
        r = f(*args, **kwargs)
        print "Executing {0} took {1} seconds".format(f.func_name,  time.time()-start)
        return r
    return wrapped

@timethis
def thistakestime():
    for x in range(10000000):
        pass

thistakestime()

System.IO.IOException: file used by another process

My reputation being too small to comment an answer, here is my feedback concerning roquen answer (using settings on xmlwriter to force the stream to close): it works perfectly and it made me save a lot of time. roquen's example requires some adjustment, here is the code that works on .NET framework 4.8 :

    XmlWriterSettings settings = new XmlWriterSettings();
    settings.CloseOutput = true;
    writer = XmlWriter.Create(stream, settings);

Reset push notification settings for app

Another just for testing solution to this is by simply changing your bundle id. Just don't forget to change it back once you're done!

Running a cron job at 2:30 AM everyday

  1. To edit:

    crontab -e
    
  2. Add this command line:

    30 2 * * * /your/command
    
    • Crontab Format:

      MIN HOUR DOM MON DOW CMD

    • Format Meanings and Allowed Value:
    • MIN Minute field 0 to 59
    • HOUR Hour field 0 to 23
    • DOM Day of Month 1-31
    • MON Month field 1-12
    • DOW Day Of Week 0-6
    • CMD Command Any command to be executed.
  3. Restart cron with latest data:

    service crond restart
    

Linux: copy and create destination dir if it does not exist

You can use find with Perl. Command will be like this:

find file | perl -lne '$t = "/path/to/copy/file/to/is/very/deep/there/"; /^(.+)\/.+$/; `mkdir -p $t$1` unless(-d "$t$1"); `cp $_ $t$_` unless(-f "$t$_");'

This command will create directory $t if it doesn't exist. And than copy file into $t only unless file exists inside $t.

How to add style from code behind?

You can't.

So just don't apply styles directly like that, and apply a class "foo", and then define that in your CSS specification:

a.foo { color : orange; }
a.foo:hover { font-weight : bold; }

Why should the static field be accessed in a static way?

There's actually a good reason:
The non-static access does not always work, for reasons of ambiguity.

Suppose we have two classes, A and B, the latter being a subclass of A, with static fields with the same name:

public class A {
    public static String VALUE = "Aaa";
}

public class B extends A {
    public static String VALUE = "Bbb";
}

Direct access to the static variable:

A.VALUE (="Aaa")
B.VALUE (="Bbb")

Indirect access using an instance (gives a compiler warning that VALUE should be statically accessed):

new B().VALUE (="Bbb")

So far, so good, the compiler can guess which static variable to use, the one on the superclass is somehow farther away, seems somehow logical.

Now to the point where it gets tricky: Interfaces can also have static variables.

public interface C {
    public static String VALUE = "Ccc";
}

public interface D {
    public static String VALUE = "Ddd";
}

Let's remove the static variable from B, and observe following situations:

  • B implements C, D
  • B extends A implements C
  • B extends A implements C, D
  • B extends A implements C where A implements D
  • B extends A implements C where C extends D
  • ...

The statement new B().VALUE is now ambiguous, as the compiler cannot decide which static variable was meant, and will report it as an error:

error: reference to VALUE is ambiguous
both variable VALUE in C and variable VALUE in D match

And that's exactly the reason why static variables should be accessed in a static way.

how to bypass Access-Control-Allow-Origin?

Okay, but you all know that the * is a wildcard and allows cross site scripting from every domain?

You would like to send multiple Access-Control-Allow-Origin headers for every site that's allowed to - but unfortunately its officially not supported to send multiple Access-Control-Allow-Origin headers, or to put in multiple origins.

You can solve this by checking the origin, and sending back that one in the header, if it is allowed:

$origin = $_SERVER['HTTP_ORIGIN'];
$allowed_domains = [
    'http://mysite1.com',
    'https://www.mysite2.com',
    'http://www.mysite2.com',
];

if (in_array($origin, $allowed_domains)) {
    header('Access-Control-Allow-Origin: ' . $origin);
}

Thats much safer. You might want to edit the matching and change it to a manual function with some regex, or something like that. At least this will only send back 1 header, and you will be sure its the one that the request came from. Please do note that all HTTP headers can be spoofed, but this header is for the client's protection. Don't protect your own data with those values. If you want to know more, read up a bit on CORS and CSRF.

Why is it safer?

Allowing access from other locations then your own trusted site allows for session highjacking. I'm going to go with a little example - image Facebook allows a wildcard origin - this means that you can make your own website somewhere, and make it fire AJAX calls (or open iframes) to facebook. This means you can grab the logged in info of the facebook of a visitor of your website. Even worse - you can script POST requests and post data on someone's facebook - just while they are browsing your website.

Be very cautious when using the ACAO headers!

Getting URL hash location, and using it in jQuery

Since jQuery 1.9, the :target selector will match the URL hash. So you could do:

$(":target").show(); // or $("ul:target").show();

Which would select the element with the ID matching the hash and show it.

How to view the current heap size that an application is using?

Personal favourite for when jvisualvm is overkill or you need cli-only: jvmtop

JvmTop 0.8.0 alpha   amd64  8 cpus, Linux 2.6.32-27, load avg 0.12
https://github.com/patric-r/jvmtop

PID MAIN-CLASS      HPCUR HPMAX NHCUR NHMAX    CPU     GC    VM USERNAME   #T DL
3370 rapperSimpleApp  165m  455m  109m  176m  0.12%  0.00% S6U37 web        21
11272 ver.resin.Resin [ERROR: Could not attach to VM]
27338 WatchdogManager   11m   28m   23m  130m  0.00%  0.00% S6U37 web        31
19187 m.jvmtop.JvmTop   20m 3544m   13m  130m  0.93%  0.47% S6U37 web        20
16733 artup.Bootstrap  159m  455m  166m  304m  0.12%  0.00% S6U37 web        46

How to update PATH variable permanently from Windows command line?

In a corporate network, where the user has only limited access and uses portable apps, there are these command line tricks:

  1. Query the user env variables: reg query "HKEY_CURRENT_USER\Environment". Use "HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Environment" for LOCAL_MACHINE.
  2. Add new user env variable: reg add "HKEY_CURRENT_USER\Environment" /v shared_dir /d "c:\shared" /t REG_SZ. Use REG_EXPAND_SZ for paths containing other %% variables.
  3. Delete existing env variable: reg delete "HKEY_CURRENT_USER\Environment" /v shared_dir.

Best Practices for securing a REST API / web service

Thanks for the excellent advice. We ended up using a custom HTTP header to pass an identity token from the client to the service, in preparation for integrating our RESTful API with the the upcoming Zermatt Identity framework from Microsoft. I have described the problem here and our solution here. I also took tweakt's advice and bought RESTful Web Services - a very good book if you're building a RESTful API of any kind.

Laravel Migration Error: Syntax error or access violation: 1071 Specified key was too long; max key length is 767 bytes

In order to avoid changing anything in your code, simply update your MySQL server to at least 5.7.7

Reference this for more info : https://laravel-news.com/laravel-5-4-key-too-long-error

Correct way to write loops for promise.

Using the standard promise object, and having the promise return the results.

function promiseMap (data, f) {
  const reducer = (promise, x) =>
    promise.then(acc => f(x).then(y => acc.push(y) && acc))
  return data.reduce(reducer, Promise.resolve([]))
}

var emails = []

function getUser(email) {
  return db.getUser(email)
}

promiseMap(emails, getUser).then(emails => {
  console.log(emails)
})

AngularJS sorting rows by table header

Here is an example that sorts by the header. This table is dynamic and changes with the JSON size.

I was able to build a dynamic table off of some other people's examples and documentation. http://jsfiddle.net/lastlink/v7pszemn/1/

<tr>
    <th class="{{header}}" ng-repeat="(header, value) in items[0]" ng-click="changeSorting(header)">
    {{header}}
  <i ng-class="selectedCls2(header)"></i>
</tr>

<tbody>
    <tr ng-repeat="row in pagedItems[currentPage] | orderBy:sort.sortingOrder:sort.reverse">
        <td ng-repeat="cell in row">
              {{cell}}
       </td>
    </tr>

Although the columns are out of order, on my .NET project they are in order.

Encrypt and decrypt a password in Java

EDIT : this answer is old. Usage of MD5 is now discouraged as it can easily be broken.


MD5 must be good enough for you I imagine? You can achieve it with MessageDigest.

MessageDigest.getInstance("MD5");

There are also other algorithms listed here.

And here's an third party version of it, if you really want: Fast MD5

Set folder for classpath

If you are using Java 6 or higher you can use wildcards of this form:

java -classpath ".;c:\mylibs\*;c:\extlibs\*" MyApp

If you would like to add all subdirectories: lib\a\, lib\b\, lib\c\, there is no mechanism for this in except:

java -classpath ".;c:\lib\a\*;c:\lib\b\*;c:\lib\c\*" MyApp

There is nothing like lib\*\* or lib\** wildcard for the kind of job you want to be done.

Global environment variables in a shell script

#!/bin/bash
export FOO=bar

or

#!/bin/bash
FOO=bar
export FOO

man export:

The shell shall give the export attribute to the variables corresponding to the specified names, which shall cause them to be in the environment of subsequently executed commands. If the name of a variable is followed by = word, then the value of that variable shall be set to word.

How to access to a child method from the parent in vue.js

To communicate a child component with another child component I've made a method in parent which calls a method in a child with:

this.$refs.childMethod()

And from the another child I've called the root method:

this.$root.theRootMethod()

It worked for me.

NOW() function in PHP

You can use the PHP date function with the correct format as the parameter,

echo date("Y-m-d H:i:s");

Ignore Duplicates and Create New List of Unique Values in Excel

Honestly I followed these examples to a tee and they simply didn't work. What I ended up doing after struggling pointlessly trying to get Excel to work was to just copy the entire contents of my column to NotePad++ where I was able to find an easy solution within minutes. Take a look at this: Removing duplicate rows in Notepad++

Edit: Here is a brief overview of how to do it in TextFX:

Plugins -> Plugin Manager -> Show Plugin Manager -> Available tab -> TextFX -> Install

After TextFX is installed in NotePad++, then you select all your text you want to remove duplicates from, then make sure to check: TextFX -> TextFX Tools -> Sort outputs only UNIQUE lines

Then click "sort lines case sensitive" or "sort lines case insensitive" and it will perform the unique sort.

Using OR operator in a jquery if statement

The logical OR '||' automatically short circuits if it meets a true condition once.

false || false || true || false = true, stops at second condition.

On the other hand, the logical AND '&&' automatically short circuits if it meets a false condition once.

false && true && true && true = false, stops at first condition.

C# Inserting Data from a form into an access Database

This answer will help in case, If you are working with Data Bases then mostly take the help of try-catch block statement, which will help and guide you with your code. Here i am showing you that how to insert some values in Data Base with a Button Click Event.

 private void button2_Click(object sender, EventArgs e)
    {
        System.Data.OleDb.OleDbConnection conn = new System.Data.OleDb.OleDbConnection();
        conn.ConnectionString = @"Provider=Microsoft.ACE.OLEDB.12.0;" +
    @"Data source= C:\Users\pir fahim shah\Documents\TravelAgency.accdb";

     try
       {
           conn.Open();
           String ticketno=textBox1.Text.ToString();                 
           String Purchaseprice=textBox2.Text.ToString();
           String sellprice=textBox3.Text.ToString();
           String my_querry = "INSERT INTO Table1(TicketNo,Sellprice,Purchaseprice)VALUES('"+ticketno+"','"+sellprice+"','"+Purchaseprice+"')";

            OleDbCommand cmd = new OleDbCommand(my_querry, conn);
            cmd.ExecuteNonQuery();

            MessageBox.Show("Data saved successfuly...!");
          }
         catch (Exception ex)
         {
             MessageBox.Show("Failed due to"+ex.Message);
         }
         finally
         {
             conn.Close();
         }

program cant start because php5.dll is missing

For Wamp x86+Phalcon users (with same error):

Take care of download the right version of Phalcon:

Phalcon 1.3.2 - Windows x86 for PHP 5.5.0 (VC11)

Create Log File in Powershell

I believe this is the simplest way of putting all what it is on the screen into a file. It is a native PS CmdLet so you don't have to change anything in yout script

Start-Transcript -Path Computer.log

Write-Host "everything will end up in Computer.log"

Stop-Transcript

How to subtract 30 days from the current datetime in mysql?

another way

SELECT COUNT(*) FROM tbl_debug WHERE TO_DAYS(`when`) < TO_DAYS(NOW())-30 ;

How to insert new cell into UITableView in Swift

For Swift 5

Remove Cell

    let indexPath = [NSIndexPath(row: yourArray-1, section: 0)]
    yourArray.remove(at: buttonTag)
    self.tableView.beginUpdates()

    self.tableView.deleteRows(at: indexPath as [IndexPath] , with: .fade)
    self.tableView.endUpdates()
    self.tableView.reloadData()// Not mendatory, But In my case its requires

Add new cell

    yourArray.append(4)

    tableView.beginUpdates()
    tableView.insertRows(at: [
        (NSIndexPath(row: yourArray.count-1, section: 0) as IndexPath)], with: .automatic)
    tableView.endUpdates()

Linux delete file with size 0

you would want to use find:

 find . -size 0 -delete