Programs & Examples On #Static typing

A programming language is said to use static typing when type checking is performed during compile-time as opposed to run-time.

Interface vs Base class

Modern style is to define IPet and PetBase.

The advantage of the interface is that other code can use it without any ties whatsoever to other executable code. Completely "clean." Also interfaces can be mixed.

But base classes are useful for simple implementations and common utilities. So provide an abstract base class as well to save time and code.

What is the difference between statically typed and dynamically typed languages?

Here is an example contrasting how Python (dynamically typed) and Go (statically typed) handle a type error:

def silly(a):
    if a > 0:
        print 'Hi'
    else:
        print 5 + '3'

Python does type checking at run time, and therefore:

silly(2)

Runs perfectly fine, and produces the expected output Hi. Error is only raised if the problematic line is hit:

silly(-1)

Produces

TypeError: unsupported operand type(s) for +: 'int' and 'str'

because the relevant line was actually executed.

Go on the other hand does type-checking at compile time:

package main

import ("fmt"
)

func silly(a int) {
    if (a > 0) {
        fmt.Println("Hi")
    } else {
        fmt.Println("3" + 5)
    }
}

func main() {
    silly(2)
}

The above will not compile, with the following error:

invalid operation: "3" + 5 (mismatched types string and int)

What is the difference between a strongly typed language and a statically typed language?

This is often misunderstood so let me clear it up.

Static/Dynamic Typing

Static typing is where the type is bound to the variable. Types are checked at compile time.

Dynamic typing is where the type is bound to the value. Types are checked at run time.

So in Java for example:

String s = "abcd";

s will "forever" be a String. During its life it may point to different Strings (since s is a reference in Java). It may have a null value but it will never refer to an Integer or a List. That's static typing.

In PHP:

$s = "abcd";          // $s is a string
$s = 123;             // $s is now an integer
$s = array(1, 2, 3);  // $s is now an array
$s = new DOMDocument; // $s is an instance of the DOMDocument class

That's dynamic typing.

Strong/Weak Typing

(Edit alert!)

Strong typing is a phrase with no widely agreed upon meaning. Most programmers who use this term to mean something other than static typing use it to imply that there is a type discipline that is enforced by the compiler. For example, CLU has a strong type system that does not allow client code to create a value of abstract type except by using the constructors provided by the type. C has a somewhat strong type system, but it can be "subverted" to a degree because a program can always cast a value of one pointer type to a value of another pointer type. So for example, in C you can take a value returned by malloc() and cheerfully cast it to FILE*, and the compiler won't try to stop you—or even warn you that you are doing anything dodgy.

(The original answer said something about a value "not changing type at run time". I have known many language designers and compiler writers and have not known one that talked about values changing type at run time, except possibly some very advanced research in type systems, where this is known as the "strong update problem".)

Weak typing implies that the compiler does not enforce a typing discpline, or perhaps that enforcement can easily be subverted.

The original of this answer conflated weak typing with implicit conversion (sometimes also called "implicit promotion"). For example, in Java:

String s = "abc" + 123; // "abc123";

This is code is an example of implicit promotion: 123 is implicitly converted to a string before being concatenated with "abc". It can be argued the Java compiler rewrites that code as:

String s = "abc" + new Integer(123).toString();

Consider a classic PHP "starts with" problem:

if (strpos('abcdef', 'abc') == false) {
  // not found
}

The error here is that strpos() returns the index of the match, being 0. 0 is coerced into boolean false and thus the condition is actually true. The solution is to use === instead of == to avoid implicit conversion.

This example illustrates how a combination of implicit conversion and dynamic typing can lead programmers astray.

Compare that to Ruby:

val = "abc" + 123

which is a runtime error because in Ruby the object 123 is not implicitly converted just because it happens to be passed to a + method. In Ruby the programmer must make the conversion explicit:

val = "abc" + 123.to_s

Comparing PHP and Ruby is a good illustration here. Both are dynamically typed languages but PHP has lots of implicit conversions and Ruby (perhaps surprisingly if you're unfamiliar with it) doesn't.

Static/Dynamic vs Strong/Weak

The point here is that the static/dynamic axis is independent of the strong/weak axis. People confuse them probably in part because strong vs weak typing is not only less clearly defined, there is no real consensus on exactly what is meant by strong and weak. For this reason strong/weak typing is far more of a shade of grey rather than black or white.

So to answer your question: another way to look at this that's mostly correct is to say that static typing is compile-time type safety and strong typing is runtime type safety.

The reason for this is that variables in a statically typed language have a type that must be declared and can be checked at compile time. A strongly-typed language has values that have a type at run time, and it's difficult for the programmer to subvert the type system without a dynamic check.

But it's important to understand that a language can be Static/Strong, Static/Weak, Dynamic/Strong or Dynamic/Weak.

Handlebars/Mustache - Is there a built in way to loop through the properties of an object?

It's actually quite easy to implement as a helper:

Handlebars.registerHelper('eachProperty', function(context, options) {
    var ret = "";
    for(var prop in context)
    {
        ret = ret + options.fn({property:prop,value:context[prop]});
    }
    return ret;
});

Then using it like so:

{{#eachProperty object}}
    {{property}}: {{value}}<br/>
{{/eachProperty }}

How to get year/month/day from a date object?

Nice formatting add-in: http://blog.stevenlevithan.com/archives/date-time-format.

With that you could write:

var now = new Date();
now.format("yyyy/mm/dd");

ReactJs: What should the PropTypes be for this.props.children?

If you want to match exactly a component type, check this

MenuPrimary.propTypes = {
  children: PropTypes.oneOfType([
    PropTypes.arrayOf(MenuPrimaryItem),
    PropTypes.objectOf(MenuPrimaryItem)
  ])
}

If you want to match exactly some component types, check this

const HeaderTypes = [
  PropTypes.objectOf(MenuPrimary),
  PropTypes.objectOf(UserInfo)
]

Header.propTypes = {
  children: PropTypes.oneOfType([
    PropTypes.arrayOf(PropTypes.oneOfType([...HeaderTypes])),
    ...HeaderTypes
  ])
}

Sublime Text 3 how to change the font size of the file sidebar?

I use Soda Dark 3 with icons enabled. So by just renaming it erases all the icons enabled with it. So I just leave the Default as it is and created a new file Soda Dark 3.sublime-theme and just have the following in the content

[
{
    "class": "label_control",
    "color": [150, 25, 25],
    "shadow_color": [24, 24, 24],
    "shadow_offset": [0, -1],
    "font.size": 16,
    "font.bold": true
},

]

So in Mac is it at /Users/gugovind/Library/Application Support/Sublime Text 3/Packages/User/

Convert a python UTC datetime to a local datetime using only python standard library?

You can't do it with only the standard library as the standard library doesn't have any timezones. You need pytz or dateutil.

>>> from datetime import datetime
>>> now = datetime.utcnow()
>>> from dateutil import tz
>>> HERE = tz.tzlocal()
>>> UTC = tz.gettz('UTC')

The Conversion:
>>> gmt = now.replace(tzinfo=UTC)
>>> gmt.astimezone(HERE)
datetime.datetime(2010, 12, 30, 15, 51, 22, 114668, tzinfo=tzlocal())

Or well, you can do it without pytz or dateutil by implementing your own timezones. But that would be silly.

How to resolve git error: "Updates were rejected because the tip of your current branch is behind"

If you have already made some commits, you can do the following

git pull --rebase

This will place all your local commits on top of newly pulled changes.

BE VERY CAREFUL WITH THIS: this will probably overwrite all your present files with the files as they are at the head of the branch in the remote repo! If this happens and you didn't want it to you can UNDO THIS CHANGE with

git rebase --abort 

... naturally you have to do that before doing any new commits!

When to use in vs ref vs out

You're correct in that, semantically, ref provides both "in" and "out" functionality, whereas out only provides "out" functionality. There are some things to consider:

  1. out requires that the method accepting the parameter MUST, at some point before returning, assign a value to the variable. You find this pattern in some of the key/value data storage classes like Dictionary<K,V>, where you have functions like TryGetValue. This function takes an out parameter that holds what the value will be if retrieved. It wouldn't make sense for the caller to pass a value into this function, so out is used to guarantee that some value will be in the variable after the call, even if it isn't "real" data (in the case of TryGetValue where the key isn't present).
  2. out and ref parameters are marshaled differently when dealing with interop code

Also, as an aside, it's important to note that while reference types and value types differ in the nature of their value, every variable in your application points to a location of memory that holds a value, even for reference types. It just happens that, with reference types, the value contained in that location of memory is another memory location. When you pass values to a function (or do any other variable assignment), the value of that variable is copied into the other variable. For value types, that means that the entire content of the type is copied. For reference types, that means that the memory location is copied. Either way, it does create a copy of the data contained in the variable. The only real relevance that this holds deals with assignment semantics; when assigning a variable or passing by value (the default), when a new assignment is made to the original (or new) variable, it does not affect the other variable. In the case of reference types, yes, changes made to the instance are available on both sides, but that's because the actual variable is just a pointer to another memory location; the content of the variable--the memory location--didn't actually change.

Passing with the ref keyword says that both the original variable and the function parameter will actually point to the same memory location. This, again, affects only assignment semantics. If a new value is assigned to one of the variables, then because the other points to the same memory location the new value will be reflected on the other side.

Saving an image in OpenCV

I know the problem! You just put a dot after "test.jpg"!

cvSaveImage("test.jpg". ,pSaveImg);

I may be wrong but I think its not good!

What is the "realm" in basic authentication

According to the RFC 7235, the realm parameter is reserved for defining protection spaces (set of pages or resources where credentials are required) and it's used by the authentication schemes to indicate a scope of protection.

For more details, see the quote below (the highlights are not present in the RFC):

2.2. Protection Space (Realm)

The "realm" authentication parameter is reserved for use by authentication schemes that wish to indicate a scope of protection.

A protection space is defined by the canonical root URI (the scheme and authority components of the effective request URI) of the server being accessed, in combination with the realm value if present. These realms allow the protected resources on a server to be partitioned into a set of protection spaces, each with its own authentication scheme and/or authorization database. The realm value is a string, generally assigned by the origin server, that can have additional semantics specific to the authentication scheme. Note that a response can have multiple challenges with the same auth-scheme but with different realms. [...]


Note 1: The framework for HTTP authentication is currently defined by the RFC 7235, which updates the RFC 2617 and makes the RFC 2616 obsolete.

Note 2: The realm parameter is no longer always required on challenges.

How to hide the bar at the top of "youtube" even when mouse hovers over it?

What I did to disable the hover state of the iframe, was to use pointer-events:none in a css style. It shows the info on load, but after that hover shouldn't trigger showing the info.

Android eclipse DDMS - Can't access data/data/ on phone to pull files

If it retures "permission denied" on adb shell -> su...

Go to "Developer Options" -> Root access -> "Apps and ADB"

Bootstrap 3 navbar active li not changing background-color

Well, I had a similar challenge. Using the inspect element tool in Firefox, I was able to trace the markup and the CSS used to style the link when clicked. On click, the list item (li) is given a class of .open and it's the anchor tag in the class that is formatted with the grey color background.

To fix this, just add this to your stylesheet.

.nav .open > a
{
    background:#759ad6;
    // Put in styling
}

Is there a better way to do optional function parameters in JavaScript?

If you're using defaults extensively, this seems much more readable:

function usageExemple(a,b,c,d){
    //defaults
    a=defaultValue(a,1);
    b=defaultValue(b,2);
    c=defaultValue(c,4);
    d=defaultValue(d,8);

    var x = a+b+c+d;
    return x;
}

Just declare this function on the global escope.

function defaultValue(variable,defaultValue){
    return(typeof variable!=='undefined')?(variable):(defaultValue);
}

Usage pattern fruit = defaultValue(fruit,'Apple');

*PS you can rename the defaultValue function to a short name, just don't use default it's a reserved word in javascript.

Optimal number of threads per core

4000 threads at one time is pretty high.

The answer is yes and no. If you are doing a lot of blocking I/O in each thread, then yes, you could show significant speedups doing up to probably 3 or 4 threads per logical core.

If you are not doing a lot of blocking things however, then the extra overhead with threading will just make it slower. So use a profiler and see where the bottlenecks are in each possibly parallel piece. If you are doing heavy computations, then more than 1 thread per CPU won't help. If you are doing a lot of memory transfer, it won't help either. If you are doing a lot of I/O though such as for disk access or internet access, then yes multiple threads will help up to a certain extent, or at the least make the application more responsive.

Saving to CSV in Excel loses regional date format

You can save your desired date format from Excel to .csv by following this procedure, hopefully an excel guru can refine further and reduce the number of steps:

  1. Create a new column DATE_TMP and set it equal to the =TEXT( oldcolumn, "date-format-arg" ) formula.

For example, in your example if your dates were in column A the value in row 1 for this new column would be:

=TEXT( A1, "dd/mm/yyyy" )

  1. Insert a blank column DATE_NEW next to your existing date column.

  2. Paste the contents of DATE_TMP into DATE_NEW using the "paste as value" option.

  3. Remove DATE_TMP and your existing date column, rename DATE_NEW to your old date column.

  4. Save as csv.

How to remove text before | character in notepad++

To replace anything that starts with "text" until the last character:

text.+(.*)$

Example

text             hsjh sdjh sd          jhsjhsdjhsdj hsd
                                                      ^
                                                      last character


To replace anything that starts with "text" until "123"

text.+(\ 123)

Example

text fuhfh283nfnd03no3 d90d3nd 3d 123 udauhdah au dauh ej2e
^                                   ^
From here                     To here

How to pass a PHP variable using the URL

You're passing link=$a and link=$b in the hrefs for A and B, respectively. They are treated as strings, not variables. The following should fix that for you:

echo '<a href="pass.php?link=' . $a . '">Link 1</a>';

// and

echo '<a href="pass.php?link=' . $b . '">Link 2</a>';

The value of $a also isn't included on pass.php. I would suggest making a common variable file and include it on all necessary pages.

Get list of filenames in folder with Javascript

For getting the list of filenames in a specified folder, you can use:

fs.readdir(directory_path, callback_function)

This will return a list which you can parse by simple list indexing like file[0],file[1], etc.

#1142 - SELECT command denied to user ''@'localhost' for table 'pma_table_uiprefs'

If you use XAMPP Path ( $cfg['Servers'][$i]['pmadb'] = 'phpmyadmin'; ) C:\xampp\phpmyadmin\config.inc.php (Probably XAMPP1.8 at Line Number 34)

Another Solution: I face same type problem "#1142 - SELECT command denied to user ''@'localhost' for table 'pma_recent'"

  1. open phpmyadmin==>setting==>Navigation frame==> Recently used tables==>0(set the value 0) ==> Save

Why avoid increment ("++") and decrement ("--") operators in JavaScript?

I think programmers should be competent in the language they are using; use it clearly; and use it well. I don't think they should artificially cripple the language they are using. I speak from experience. I once worked literally next door to a Cobol shop where they didn't use ELSE 'because it was too complicated'. Reductio ad absurdam.

How to center a WPF app on screen?

I prefer to put it in the WPF code.

In [WindowName].xaml file:

<Window x:Class=...
...
WindowStartupLocation ="CenterScreen">

Changing background color of selected cell?

Works for me

UIView *customColorView = [[UIView alloc] init];
    customColorView.backgroundColor = [UIColor colorWithRed:180/255.0 
                                                      green:138/255.0 
                                                       blue:171/255.0 
                                                      alpha:0.5];
    cell.selectedBackgroundView =  customColorView;

git ignore exception

Just add ! before an exclusion rule.

According to the gitignore man page:

Patterns have the following format:

...

  • An optional prefix ! which negates the pattern; any matching file excluded by a previous pattern will become included again. If a negated pattern matches, this will override lower precedence patterns sources.

Error:Execution failed for task ':app:compileDebugKotlin'. > Compilation error. See log for more details

run gradle assembleDebug --scan in Android studio Terminal, in my case I removed an element in XML and forgotten to remove it from code, but the compiler couldn't compile and show Error:Execution failed for task ':app:compileDebugKotlin'. > Compilation error. See log for more details to me.

enter image description here

Matplotlib - global legend and title aside subplots

Global title: In newer releases of matplotlib one can use Figure.suptitle() method of Figure:

import matplotlib.pyplot as plt
fig = plt.gcf()
fig.suptitle("Title centered above all subplots", fontsize=14)

Alternatively (based on @Steven C. Howell's comment below (thank you!)), use the matplotlib.pyplot.suptitle() function:

 import matplotlib.pyplot as plt
 # plot stuff
 # ...
 plt.suptitle("Title centered above all subplots", fontsize=14)

How to iterate over each string in a list of strings and operate on it's elements

Use range() instead, like the following :

for i in range(len(words)):
    ...

What causes the Broken Pipe Error?

Maybe the 40 bytes fits into the pipe buffer, and the 40000 bytes doesn't?

Edit:

The sending process is sent a SIGPIPE signal when you try to write to a closed pipe. I don't know exactly when the signal is sent, or what effect the pipe buffer has on this. You may be able to recover by trapping the signal with the sigaction call.

What is console.log?

Use console.log to add debugging information to your page.

Many people use alert(hasNinjas) for this purpose but console.log(hasNinjas) is easier to work with. Using an alert pop-ups up a modal dialog box that blocks the user interface.

Edit: I agree with Baptiste Pernet and Jan Hancic that it is a very good idea to check if window.console is defined first so that your code doesn't break if there is no console available.

How do you return the column names of a table?

Something like this?

sp_columns @table_name=your table name

Java - No enclosing instance of type Foo is accessible

Thing is an inner class with an automatic connection to an instance of Hello. You get a compile error because there is no instance of Hello for it to attach to. You can fix it most easily by changing it to a static nested class which has no connection:

static class Thing

Clearing a string buffer/builder after loop

You have two options:

Either use:

sb.setLength(0);  // It will just discard the previous data, which will be garbage collected later.  

Or use:

sb.delete(0, sb.length());  // A bit slower as it is used to delete sub sequence.  

NOTE

Avoid declaring StringBuffer or StringBuilder objects within the loop else it will create new objects with each iteration. Creating of objects requires system resources, space and also takes time. So for long run, avoid declaring them within a loop if possible.

What's the difference between dependencies, devDependencies and peerDependencies in npm package.json file?

As an example, mocha would normally be a devDependency, since testing isn't necessary in production, while express would be a dependency.

Unable to use Intellij with a generated sources folder

I had the same issue with Eclipse a couple of months ago when importing my project. Now I had the same with intelliJ. Here is how someone helped me to solve this in IntelliJ:

Menu => View => Tools windows => Maven Project In the spring_user value => Run Configuration, choose clean install. This should do a clean install and after this you should be able to see the classes enter image description here

vue.js 2 how to watch store values from vuex

When you want to watch on state level, it can be done this way:

let App = new Vue({
    //...
    store,
    watch: {
        '$store.state.myState': function (newVal) {
            console.log(newVal);
            store.dispatch('handleMyStateChange');
        }
    },
    //...
});

Relative path to absolute path in C#?

string exactPath = Path.GetFullPath(yourRelativePath);

works

How to "set a breakpoint in malloc_error_break to debug"

I had given permissions I shouldn't have to write in some folders (especially /usr/bin/), and that caused the problem. I fixed it by opening Disk Utility and running 'Repair Disk Permissions' on the Macintosh HD disk.

Error reading JObject from JsonReader. Current JsonReader item is not an object: StartArray. Path

The first part of your question is a duplicate of Why do I get a JsonReaderException with this code?, but the most relevant part from that (my) answer is this:

[A] JObject isn't the elementary base type of everything in JSON.net, but JToken is. So even though you could say,

object i = new int[0];

in C#, you can't say,

JObject i = JObject.Parse("[0, 0, 0]");

in JSON.net.

What you want is JArray.Parse, which will accept the array you're passing it (denoted by the opening [ in your API response). This is what the "StartArray" in the error message is telling you.

As for what happened when you used JArray, you're using arr instead of obj:

var rcvdData = JsonConvert.DeserializeObject<LocationData>(arr /* <-- Here */.ToString(), settings);

Swap that, and I believe it should work.

Although I'd be tempted to deserialize arr directly as an IEnumerable<LocationData>, which would save some code and effort of looping through the array. If you aren't going to use the parsed version separately, it's best to avoid it.

React-Redux: Actions must be plain objects. Use custom middleware for async actions

Make use of Arrow functions it improves the readability of code. No need to return anything in API.fetchComments, Api call is asynchronous when the request is completed then will get the response, there you have to just dispatch type and data.

Below code does the same job by making use of Arrow functions.

export const bindComments = postId => {
  return dispatch => {
    API.fetchComments(postId).then(comments => {
      dispatch({
        type: BIND_COMMENTS,
        comments,
        postId
      });
    });
  };
};

Wordpress plugin install: Could not create directory

If you have installed wordpress using apt, the config files are split in multiple directories. In that case you need to run:

sudo chown -R -h www-data:www-data /var/lib/wordpress/wp-content/
sudo chown -R -h www-data:www-data /usr/share/wordpress/wp-content/

The -h switch changes the permissions for symlinks as well, otherwise they are not removable by user www-data

Matplotlib: ValueError: x and y must have same first dimension

Changing your lists to numpy arrays will do the job!!

import matplotlib.pyplot as plt
from scipy import stats
import numpy as np 

x = np.array([0.46,0.59,0.68,0.99,0.39,0.31,1.09,0.77,0.72,0.49,0.55,0.62,0.58,0.88,0.78]) # x is a numpy array now
y = np.array([0.315,0.383,0.452,0.650,0.279,0.215,0.727,0.512,0.478,0.335,0.365,0.424,0.390,0.585,0.511]) # y is a numpy array now
xerr = [0.01]*15
yerr = [0.001]*15

plt.rc('font', family='serif', size=13)
m, b = np.polyfit(x, y, 1)
plt.plot(x,y,'s',color='#0066FF')
plt.plot(x, m*x + b, 'r-') #BREAKS ON THIS LINE
plt.errorbar(x,y,xerr=xerr,yerr=0,linestyle="None",color='black')
plt.xlabel('$\Delta t$ $(s)$',fontsize=20)
plt.ylabel('$\Delta p$ $(hPa)$',fontsize=20)
plt.autoscale(enable=True, axis=u'both', tight=False)
plt.grid(False)
plt.xlim(0.2,1.2)
plt.ylim(0,0.8)
plt.show()

enter image description here

inline if statement java, why is not working

(inline if) in java won't work if you are using 'if' statement .. the right syntax is in the following example:

int y = (c == 19) ? 7 : 11 ; 

or

String y = (s > 120) ? "Slow Down" : "Safe";
System.out.println(y);

as You can see the type of the variable Y is the same as the return value ...

in your case it is better to use the normal if statement not inline if as it is in the pervious answer without "?"

if (compareChar(curChar, toChar("0"))) getButtons().get(i).setText("§");

How can I convert this foreach code to Parallel.ForEach?

string[] lines = File.ReadAllLines(txtProxyListPath.Text);

// No need for the list
// List<string> list_lines = new List<string>(lines); 

Parallel.ForEach(lines, line =>
{
    //My Stuff
});

This will cause the lines to be parsed in parallel, within the loop. If you want a more detailed, less "reference oriented" introduction to the Parallel class, I wrote a series on the TPL which includes a section on Parallel.ForEach.

How to write a confusion matrix in Python?

If you don't want scikit-learn to do the work for you...

    import numpy
    actual = numpy.array(actual)
    predicted = numpy.array(predicted)

    # calculate the confusion matrix; labels is numpy array of classification labels
    cm = numpy.zeros((len(labels), len(labels)))
    for a, p in zip(actual, predicted):
        cm[a][p] += 1

    # also get the accuracy easily with numpy
    accuracy = (actual == predicted).sum() / float(len(actual))

Or take a look at a more complete implementation here in NLTK.

UIDevice uniqueIdentifier deprecated - What to do now?

Dont use these libraries - libOmnitureAppMeasurement, It does use uniqueIdentifier which apple doesnt support anymore

Update an outdated branch against master in a Git repo

Update the master branch, which you need to do regardless.

Then, one of:

  1. Rebase the old branch against the master branch. Solve the merge conflicts during rebase, and the result will be an up-to-date branch that merges cleanly against master.

  2. Merge your branch into master, and resolve the merge conflicts.

  3. Merge master into your branch, and resolve the merge conflicts. Then, merging from your branch into master should be clean.

None of these is better than the other, they just have different trade-off patterns.

I would use the rebase approach, which gives cleaner overall results to later readers, in my opinion, but that is nothing aside from personal taste.

To rebase and keep the branch you would:

git checkout <branch> && git rebase <target>

In your case, check out the old branch, then

git rebase master 

to get it rebuilt against master.

AttributeError: 'numpy.ndarray' object has no attribute 'append'

I got this error after change a loop in my program, let`s see:

for ...
  for ... 
     x_batch.append(one_hot(int_word, vocab_size))
     y_batch.append(one_hot(int_nb, vocab_size, value))
  ...
  ...
  if ...
        x_batch = np.asarray(x_batch)
        y_batch = np.asarray(y_batch)
...

In fact, I was reusing the variable and forgot to reset them inside the external loop, like the comment of John Lyon:

for ...
  x_batch = []
  y_batch = []
  for ... 
     x_batch.append(one_hot(int_word, vocab_size))
     y_batch.append(one_hot(int_nb, vocab_size, value))
  ...
  ...
  if ...
        x_batch = np.asarray(x_batch)
        y_batch = np.asarray(y_batch)
...

Then, check if you are using np.asarray() or something like that.

Online SQL syntax checker conforming to multiple databases

I haven't ever seen such a thing, but there is this dev tool that includes a syntax checker for oracle, mysql, db2, and sql server... http://www.sqlparser.com/index.php

However this seems to be just the library. You'd need to build an app to leverage the parser to do what you want. And the Enterprise edition that includes all of the databases would cost you $450... ouch!

EDIT: And, after saying that - it looks like someone might already have done what you want using that library: http://www.wangz.net/cgi-bin/pp/gsqlparser/sqlpp/sqlformat.tpl

The online tool doesn't automatically check against each DB though, you need to run each manually. Nor can I say how good it is at checking the syntax. That you'd need to investigate yourself.

How to specify preference of library path?

Add the path to where your new library is to LD_LIBRARY_PATH (it has slightly different name on Mac ...)

Your solution should work with using the -L/my/dir -lfoo options, at runtime use LD_LIBRARY_PATH to point to the location of your library.

Careful with using LD_LIBRARY_PATH - in short (from link):

..implications..:
Security: Remember that the directories specified in LD_LIBRARY_PATH get searched before(!) the standard locations? In that way, a nasty person could get your application to load a version of a shared library that contains malicious code! That’s one reason why setuid/setgid executables do neglect that variable!
Performance: The link loader has to search all the directories specified, until it finds the directory where the shared library resides – for ALL shared libraries the application is linked against! This means a lot of system calls to open(), that will fail with “ENOENT (No such file or directory)”! If the path contains many directories, the number of failed calls will increase linearly, and you can tell that from the start-up time of the application. If some (or all) of the directories are in an NFS environment, the start-up time of your applications can really get long – and it can slow down the whole system!
Inconsistency: This is the most common problem. LD_LIBRARY_PATH forces an application to load a shared library it wasn’t linked against, and that is quite likely not compatible with the original version. This can either be very obvious, i.e. the application crashes, or it can lead to wrong results, if the picked up library not quite does what the original version would have done. Especially the latter is sometimes hard to debug.

OR

Use the rpath option via gcc to linker - runtime library search path, will be used instead of looking in standard dir (gcc option):

-Wl,-rpath,$(DEFAULT_LIB_INSTALL_PATH)

This is good for a temporary solution. Linker first searches the LD_LIBRARY_PATH for libraries before looking into standard directories.

If you don't want to permanently update LD_LIBRARY_PATH you can do it on the fly on command line:

LD_LIBRARY_PATH=/some/custom/dir ./fooo

You can check what libraries linker knows about using (example):

/sbin/ldconfig -p | grep libpthread
        libpthread.so.0 (libc6, OS ABI: Linux 2.6.4) => /lib/libpthread.so.0

And you can check which library your application is using:

ldd foo
        linux-gate.so.1 =>  (0xffffe000)
        libpthread.so.0 => /lib/libpthread.so.0 (0xb7f9e000)
        libxml2.so.2 => /usr/lib/libxml2.so.2 (0xb7e6e000)
        librt.so.1 => /lib/librt.so.1 (0xb7e65000)
        libm.so.6 => /lib/libm.so.6 (0xb7d5b000)
        libc.so.6 => /lib/libc.so.6 (0xb7c2e000)
        /lib/ld-linux.so.2 (0xb7fc7000)
        libdl.so.2 => /lib/libdl.so.2 (0xb7c2a000)
        libz.so.1 => /lib/libz.so.1 (0xb7c18000)

Rewrite URL after redirecting 404 error htaccess

In your .htaccess file , if you are using apache you can try with

Rule for Error Page - 404

ErrorDocument 404 http://www.domain.com/notFound.html

How to set selected value from Combobox?

cmbEmployeeStatus.Text = "text"

Multi-line bash commands in makefile

You can use backslash for line continuation. However note that the shell receives the whole command concatenated into a single line, so you also need to terminate some of the lines with a semicolon:

foo:
    for i in `find`;     \
    do                   \
        all="$$all $$i"; \
    done;                \
    gcc $$all

But if you just want to take the whole list returned by the find invocation and pass it to gcc, you actually don't necessarily need a multiline command:

foo:
    gcc `find`

Or, using a more shell-conventional $(command) approach (notice the $ escaping though):

foo:
    gcc $$(find)

Unable to load script.Make sure you are either running a Metro server or that your bundle 'index.android.bundle' is packaged correctly for release

I've encountered the same issue while following the React Native tutorial (developing on Linux and targeting Android).

This issue helped me resolve the problem in following steps. Run following commands in the below sequence:

  1. (in project directory) mkdir android/app/src/main/assets
  2. react-native bundle --platform android --dev false --entry-file index.js --bundle-output android/app/src/main/assets/index.android.bundle --assets-dest android/app/src/main/res
  3. react-native run-android

You can automate the above steps by placing them in scripts part of package.json like this:

"android-linux": "react-native bundle --platform android --dev false --entry-file index.js --bundle-output android/app/src/main/assets/index.android.bundle --assets-dest android/app/src/main/res && react-native run-android"

Then you can just execute npm run android-linux from your command line every time.

Group By Eloquent ORM

Laravel 5

This is working for me (i use laravel 5.6).

$collection = MyModel::all()->groupBy('column');

If you want to convert the collection to plain php array, you can use toArray()

$array = MyModel::all()->groupBy('column')->toArray();

Remove padding or margins from Google Charts

There is this possibility like Aman Virk mentioned:

var options = {
    chartArea:{left:10,top:20,width:"100%",height:"100%"}
};

But keep in mind that the padding and margin aren't there to bother you. If you have the possibility to switch between different types of charts like a ColumnChart and the one with vertical columns then you need some margin for displaying the labels of those lines.

If you take away that margin then you will end up showing only a part of the labels or no labels at all.

So if you just have one chart type then you can change the margin and padding like Arman said. But if it's possible to switch don't change them.

Rename MySQL database

In short no. It is generally thought to be too dangerous to rename a database. MySQL had that feature for a bit, but it was removed. You would be better off using the workbench to export both the schema and data to SQL then changing the CREATE DATABASE name there before you run/import it.

Input type DateTime - Value format?

This article seems to show the valid types that are acceptable

<time>2009-11-13</time>
 <!-- without @datetime content must be a valid date, time, or precise datetime -->
<time datetime="2009-11-13">13<sup>th</sup> November</time>
 <!-- when using @datetime the content can be anything relevant -->
<time datetime="20:00">starting at 8pm</time>
 <!-- time example -->
<time datetime="2009-11-13T20:00+00:00">8pm on my birthday</time>
 <!-- datetime with time-zone example -->
<time datetime="2009-11-13T20:00Z">8pm on my birthday</time>
 <!-- datetime with time-zone “Z” -->

This one covers using it in the <input> field:

<input type="date" name="d" min="2011-08-01" max="2011-08-15"> This example of the HTML5 input type "date" combine with the attributes min and max shows how we can restrict the dates a user can input. The attributes min and max are not dependent on each other and can be used independently.

<input type="time" name="t" value="12:00"> The HTML5 input type "time" allows users to choose a corresponding time that is displayed in a 24hour format. If we did not include the default value of "12:00" the time would set itself to the time of the users local machine.

<input type="week" name="w"> The HTML5 Input type week will display the numerical version of the week denoted by a "W" along with the corresponding year.

<input type="month" name="m"> The HTML5 input type month does exactly what you might expect it to do. It displays the month. To be precise it displays the numerical version of the month along with the year.

<input type="datetime" name="dt"> The HTML5 input type Datetime displays the UTC date and time code. User can change the the time steps forward or backward in one minute increments. If you wish to display the local date and time of the user you will need to use the next example datetime-local

<input type="datetime-local" name="dtl" step="7200"> Because datetime steps through one minute at a time, you may want to change the default increment by using the attribute "step". In the following example we will have it increment by two hours by setting the attribute step to 7200 (60seconds X 60 minutes X 2).

Can we convert a byte array into an InputStream in Java?

Use ByteArrayInputStream:

InputStream is = new ByteArrayInputStream(decodedBytes);

Numpy AttributeError: 'float' object has no attribute 'exp'

Probably there's something wrong with the input values for X and/or T. The function from the question works ok:

import numpy as np
from math import e

def sigmoid(X, T):
  return 1.0 / (1.0 + np.exp(-1.0 * np.dot(X, T)))

X = np.array([[1, 2, 3], [5, 0, 0]])
T = np.array([[1, 2], [1, 1], [4, 4]])

print(X.dot(T))
# Just to see if values are ok
print([1. / (1. + e ** el) for el in [-5, -10, -15, -16]])
print()
print(sigmoid(X, T))

Result:

[[15 16]
 [ 5 10]]

[0.9933071490757153, 0.9999546021312976, 0.999999694097773, 0.9999998874648379]

[[ 0.99999969  0.99999989]
 [ 0.99330715  0.9999546 ]]

Probably it's the dtype of your input arrays. Changing X to:

X = np.array([[1, 2, 3], [5, 0, 0]], dtype=object)

Gives:

Traceback (most recent call last):
  File "/[...]/stackoverflow_sigmoid.py", line 24, in <module>
    print sigmoid(X, T)
  File "/[...]/stackoverflow_sigmoid.py", line 14, in sigmoid
    return 1.0 / (1.0 + np.exp(-1.0 * np.dot(X, T)))
AttributeError: exp

How to solve npm error "npm ERR! code ELIFECYCLE"

I'm using ubuntu 18.04 LTS release and I faced the same problem I tried to clean cache as above suggestions but it didn't work for me. However, I found another solution.

echo 65536 | sudo tee -a /proc/sys/fs/inotify/max_user_watches

npm start

I run this command and it started to work

Explode PHP string by new line

Lots of things here:

  • You need to use double quotes, not single quotes, otherwise the escaped characters won't be escaped.
  • The normal sequence is \r\n, not \n\r.
  • Depending on the source, you may just be getting \n without the \r (or even in unusual cases, possibly just the \r)

Given the last point, you may find preg_split() using all the possible variants will give you a more reliable way of splitting the data than explode(). But alternatively you could use explode() with just \n, and then use trim() to remove any \r characters that are left hanging around.

Java: How to Indent XML Generated by Transformer

The following code is working for me with Java 7. I set the indent (yes) and indent-amount (2) on the transformer (not the transformer factory) to get it working.

TransformerFactory tf = TransformerFactory.newInstance();
Transformer t = tf.newTransformer();
t.setOutputProperty("{http://xml.apache.org/xslt}indent-amount", "2");
t.setOutputProperty(OutputKeys.INDENT, "yes");
t.transform(source, result);

@mabac's solution to set the attribute didn't work for me, but @lapo's comment proved helpful.

Use jQuery to hide a DIV when the user clicks outside of it

Return false if you click on .form_wrapper:

$('body').click(function() {
  $('.form_wrapper').click(function(){
  return false
});
   $('.form_wrapper').hide();
});

//$('.form_wrapper').click(function(event){
//   event.stopPropagation();
//});

Matching strings with wildcard

*X*YZ* = string contains X and contains YZ

@".*X.*YZ"

X*YZ*P = string starts with X, contains YZ and ends with P.

@"^X.*YZ.*P$"

Changing Fonts Size in Matlab Plots

If you want to change font size for all the text in a figure, you can use findall to find all text handles, after which it's easy:

figureHandle = gcf;
%# make all text in the figure to size 14 and bold
set(findall(figureHandle,'type','text'),'fontSize',14,'fontWeight','bold')

Case statement with multiple values in each 'when' block

Another nice way to put your logic in data is something like this:

# Initialization.
CAR_TYPES = {
  foo_type: ['honda', 'acura', 'mercedes'],
  bar_type: ['toyota', 'lexus']
  # More...
}
@type_for_name = {}
CAR_TYPES.each { |type, names| names.each { |name| @type_for_name[type] = name } }

case @type_for_name[car]
when :foo_type
  # do foo things
when :bar_type
  # do bar things
end

How can I convert an image into Base64 string using JavaScript?

Here is the way you can do with Javascript Promise.

const getBase64 = (file) => new Promise(function (resolve, reject) {
    let reader = new FileReader();
    reader.readAsDataURL(file);
    reader.onload = () => resolve(reader.result)
    reader.onerror = (error) => reject('Error: ', error);
})

Now, use it in event handler.

const _changeImg = (e) => {
        const file = e.target.files[0];
        let encoded;
        getBase64(file)
          .then((result) => {
            encoded = result;
           })
          .catch(e => console.log(e))
    }

What's the difference between faking, mocking, and stubbing?

stub and fake are objects in that they can vary their response based on input parameters. the main difference between them is that a Fake is closer to a real-world implementation than a stub. Stubs contain basically hard-coded responses to an expected request. Let see an example:

public class MyUnitTest {

 @Test
 public void testConcatenate() {
  StubDependency stubDependency = new StubDependency();
  int result = stubDependency.toNumber("one", "two");
  assertEquals("onetwo", result);
 }
}

public class StubDependency() {
 public int toNumber(string param) {
  if (param == “one”) {
   return 1;
  }
  if (param == “two”) {
   return 2;
  }
 }
}

A mock is a step up from fakes and stubs. Mocks provide the same functionality as stubs but are more complex. They can have rules defined for them that dictate in what order methods on their API must be called. Most mocks can track how many times a method was called and can react based on that information. Mocks generally know the context of each call and can react differently in different situations. Because of this, mocks require some knowledge of the class they are mocking. a stub generally cannot track how many times a method was called or in what order a sequence of methods was called. A mock looks like:

public class MockADependency {

 private int ShouldCallTwice;
 private boolean ShouldCallAtEnd;
 private boolean ShouldCallFirst;

 public int StringToInteger(String s) {
  if (s == "abc") {
   return 1;
  }
  if (s == "xyz") {
   return 2;
  }
  return 0;
 }

 public void ShouldCallFirst() {
  if ((ShouldCallTwice > 0) || ShouldCallAtEnd)
   throw new AssertionException("ShouldCallFirst not first thod called");
  ShouldCallFirst = true;
 }

 public int ShouldCallTwice(string s) {
  if (!ShouldCallFirst)
   throw new AssertionException("ShouldCallTwice called before ShouldCallFirst");
  if (ShouldCallAtEnd)
   throw new AssertionException("ShouldCallTwice called after ShouldCallAtEnd");
  if (ShouldCallTwice >= 2)
   throw new AssertionException("ShouldCallTwice called more than twice");
  ShouldCallTwice++;
  return StringToInteger(s);
 }

 public void ShouldCallAtEnd() {
  if (!ShouldCallFirst)
   throw new AssertionException("ShouldCallAtEnd called before ShouldCallFirst");
  if (ShouldCallTwice != 2) throw new AssertionException("ShouldCallTwice not called twice");
  ShouldCallAtEnd = true;
 }

}

"Fade" borders in CSS

I know this is old but this seems to work well for me in 2020...

Using the border-image CSS property I was able to quickly manipulate the borders for this fading purpose.

Note: I don't think border-image works well with border-radius... I seen someone saying that somewhere but for this purpose it works well.

1 Liner:

CSS

 .bbdr_rfade_1      { border: 4px solid; border-image: linear-gradient(90deg, rgba(60,74,83,0.90), rgba(60,74,83,.00)) 1; border-left:none; border-top:none; border-right:none;  }

HTML

<div class = 'bbdr_rfade_1'>Oh I am so going to not up-vote this guy...</div>

Declare variable MySQL trigger

Agree with neubert about the DECLARE statements, this will fix syntax error. But I would suggest you to avoid using openning cursors, they may be slow.

For your task: use INSERT...SELECT statement which will help you to copy data from one table to another using only one query.

INSERT ... SELECT Syntax.

How do I resolve "Cannot find module" error using Node.js?

I faced the same problem when someone else in the team updated package.json in SVN. Merely removing the node_modules directory did not help. How I solved the problem is:

rm -rf node_modules
rm package.json
rm package-lock.json
svn up
npm install
ng build --env=prod

Hope this helps someone!

How to stick <footer> element at the bottom of the page (HTML5 and CSS3)?

I would use this in HTML 5... Just sayin

#footer {
  position: absolute;
  bottom: 0;
  width: 100%;
  height: 60px;
  background-color: #f5f5f5;
}

How to avoid the need to specify the WSDL location in a CXF or JAX-WS generated webservice client?

For those using org.jvnet.jax-ws-commons:jaxws-maven-plugin to generate a client from WSDL at build-time:

  • Place the WSDL somewhere in your src/main/resources
  • Do not prefix the wsdlLocation with classpath:
  • Do prefix the wsdlLocation with /

Example:

  • WSDL is stored in /src/main/resources/foo/bar.wsdl
  • Configure jaxws-maven-plugin with <wsdlDirectory>${basedir}/src/main/resources/foo</wsdlDirectory> and <wsdlLocation>/foo/bar.wsdl</wsdlLocation>

Bootstrap 3 collapse accordion: collapse all works but then cannot expand all while maintaining data-parent

For whatever reason $('.panel-collapse').collapse({'toggle': true, 'parent': '#accordion'}); only seems to work the first time and it only works to expand the collapsible. (I tried to start with a expanded collapsible and it wouldn't collapse.)

It could just be something that runs once the first time you initialize collapse with those parameters.

You will have more luck using the show and hide methods.

Here is an example:

$(function() {

  var $active = true;

  $('.panel-title > a').click(function(e) {
    e.preventDefault();
  });

  $('.collapse-init').on('click', function() {
    if(!$active) {
      $active = true;
      $('.panel-title > a').attr('data-toggle', 'collapse');
      $('.panel-collapse').collapse('hide');
      $(this).html('Click to disable accordion behavior');
    } else {
      $active = false;
      $('.panel-collapse').collapse('show');
      $('.panel-title > a').attr('data-toggle','');
      $(this).html('Click to enable accordion behavior');
    }
  });

});

http://bootply.com/98201

Update

Granted KyleMit seems to have a way better handle on this then me. I'm impressed with his answer and understanding.

I don't understand what's going on or why the show seemed to be toggling in some places.

But After messing around for a while.. Finally came with the following solution:

$(function() {
  var transition = false;
  var $active = true;

  $('.panel-title > a').click(function(e) {
    e.preventDefault();
  });

  $('#accordion').on('show.bs.collapse',function(){
    if($active){
        $('#accordion .in').collapse('hide');
    }
  });

  $('#accordion').on('hidden.bs.collapse',function(){
    if(transition){
        transition = false;
        $('.panel-collapse').collapse('show');
    }
  });

  $('.collapse-init').on('click', function() {
    $('.collapse-init').prop('disabled','true');
    if(!$active) {
      $active = true;
      $('.panel-title > a').attr('data-toggle', 'collapse');
      $('.panel-collapse').collapse('hide');
      $(this).html('Click to disable accordion behavior');
    } else {
      $active = false;
      if($('.panel-collapse.in').length){
        transition = true;
        $('.panel-collapse.in').collapse('hide');       
      }
      else{
        $('.panel-collapse').collapse('show');
      }
      $('.panel-title > a').attr('data-toggle','');
      $(this).html('Click to enable accordion behavior');
    }
    setTimeout(function(){
        $('.collapse-init').prop('disabled','');
    },800);
  });
});

http://bootply.com/98239

Android Notification Sound

You have to use builder.setSound

Intent notificationIntent = new Intent(MainActivity.this, MainActivity.class);  

                PendingIntent contentIntent = PendingIntent.getActivity(MainActivity.this, 0, notificationIntent,   
                        PendingIntent.FLAG_UPDATE_CURRENT);  

                builder.setContentIntent(contentIntent);  
                builder.setAutoCancel(true);
                builder.setLights(Color.BLUE, 500, 500);
                long[] pattern = {500,500,500,500,500,500,500,500,500};
                builder.setVibrate(pattern);
                builder.setStyle(new NotificationCompat.InboxStyle());
                 Uri alarmSound = RingtoneManager.getDefaultUri(RingtoneManager.TYPE_RINGTONE);
                    if(alarmSound == null){
                        alarmSound = RingtoneManager.getDefaultUri(RingtoneManager.TYPE_RINGTONE);
                        if(alarmSound == null){
                            alarmSound = RingtoneManager.getDefaultUri(RingtoneManager.TYPE_NOTIFICATION);
                        }
                    }

                // Add as notification  
                NotificationManager manager = (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);  
             builder.setSound(alarmSound);
                manager.notify(1, builder.build());  

Unit test naming best practices

I should add that the keeping your tests in the same package but in a parallel directory to the source being tested eliminates the bloat of the code once your ready to deploy it without having to do a bunch of exclude patterns.

I personally like the best practices described in "JUnit Pocket Guide" ... it's hard to beat a book written by the co-author of JUnit!

Jquery Date picker Default Date

While the defaultDate does not set the widget. What is needed is something like:

$(".datepicker").datepicker({
    showButtonPanel: true,
    numberOfMonths: 2

});

$(".datepicker[value='']").datepicker("setDate", "-0d"); 

Convert.ToDateTime: how to set format

You can use Convert.ToDateTime is it is shown at How to convert a Datetime string to a current culture datetime string

DateTimeFormatInfo usDtfi = new CultureInfo("en-US", false).DateTimeFormat;

var result = Convert.ToDateTime("12/01/2011", usDtfi)

OpenCV NoneType object has no attribute shape

I faced the same problem today, please check for the path of the image as mentioned by cybseccrypt. After imread, try printing the image and see. If you get a value, it means the file is open.

Code:

img_src = cv2.imread('/home/deepak/python-workout/box2.jpg',0) print img_src

Hope this helps!

Count how many rows have the same value

Try this Query

select NUM, count(1) as count 
from tbl 
where num = 1
group by NUM
--having count(1) (You condition)

SQL FIDDLE

How does System.out.print() work?

I think you are confused with the printf(String format, Object... args) method. The first argument is the format string, which is mandatory, rest you can pass an arbitrary number of Objects.

There is no such overload for both the print() and println() methods.

Convert AM/PM time to 24 hours format?

DateTime dt = DateTime.Parse("01:00 pm"); //Time in string formate

TimeSpan time = new TimeSpan(); 

time = dt.TimeOfDay;

Console.WriteLine(time);

Result : 13:00:00

How to detect orientation change?

Easy, this works in iOS8 and 9 / Swift 2 / Xcode7, just put this code inside your viewcontroller.swift. It will print the screen dimensions with every orientation change, you can put your own code instead:

override func didRotateFromInterfaceOrientation(fromInterfaceOrientation: UIInterfaceOrientation) {
        getScreenSize()
    }
    var screenWidth:CGFloat=0
    var screenHeight:CGFloat=0
    func getScreenSize(){
        screenWidth=UIScreen.mainScreen().bounds.width
        screenHeight=UIScreen.mainScreen().bounds.height
        print("SCREEN RESOLUTION: "+screenWidth.description+" x "+screenHeight.description)
    }

Retrieve list of tasks in a queue in Celery

As far as I know Celery does not give API for examining tasks that are waiting in the queue. This is broker-specific. If you use Redis as a broker for an example, then examining tasks that are waiting in the celery (default) queue is as simple as:

  1. connect to the broker database
  2. list items in the celery list (LRANGE command for an example)

Keep in mind that these are tasks WAITING to be picked by available workers. Your cluster may have some tasks running - those will not be in this list as they have already been picked.

Concept of void pointer in C programming

Void pointers are pointers that has no data type associated with it.A void pointer can hold address of any type and can be typcasted to any type. But, void pointer cannot be directly be dereferenced.

int x = 1;
void *p1;
p1 = &x;
cout << *p1 << endl; // this will give error
cout << (int *)(*p) << endl; // this is valid

What does the construct x = x || y mean?

It means the title argument is optional. So if you call the method with no arguments it will use a default value of "Error".

It's shorthand for writing:

if (!title) {
  title = "Error";
}

This kind of shorthand trick with boolean expressions is common in Perl too. With the expression:

a OR b

it evaluates to true if either a or b is true. So if a is true you don't need to check b at all. This is called short-circuit boolean evaluation so:

var title = title || "Error";

basically checks if title evaluates to false. If it does, it "returns" "Error", otherwise it returns title.

How to getElementByClass instead of GetElementById with JavaScript?

The getElementsByClassName method is now natively supported by the most recent versions of Firefox, Safari, Chrome, IE and Opera, you could make a function to check if a native implementation is available, otherwise use the Dustin Diaz method:

function getElementsByClassName(node,classname) {
  if (node.getElementsByClassName) { // use native implementation if available
    return node.getElementsByClassName(classname);
  } else {
    return (function getElementsByClass(searchClass,node) {
        if ( node == null )
          node = document;
        var classElements = [],
            els = node.getElementsByTagName("*"),
            elsLen = els.length,
            pattern = new RegExp("(^|\\s)"+searchClass+"(\\s|$)"), i, j;

        for (i = 0, j = 0; i < elsLen; i++) {
          if ( pattern.test(els[i].className) ) {
              classElements[j] = els[i];
              j++;
          }
        }
        return classElements;
    })(classname, node);
  }
}

Usage:

function toggle_visibility(className) {
   var elements = getElementsByClassName(document, className),
       n = elements.length;
   for (var i = 0; i < n; i++) {
     var e = elements[i];

     if(e.style.display == 'block') {
       e.style.display = 'none';
     } else {
       e.style.display = 'block';
     }
  }
}

Generate a range of dates using SQL

There's no need to use extra large tables or ALL_OBJECTS table:

SELECT TRUNC (SYSDATE - ROWNUM) dt
  FROM DUAL CONNECT BY ROWNUM < 366

will do the trick.

FloatingActionButton example with Support Library

I just found some issues on FAB and I want to enhance another answer.


setRippleColor issue

So, the issue will come once you set the ripple color (FAB color on pressed) programmatically through setRippleColor. But, we still have an alternative way to set it, i.e. by calling:

FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
ColorStateList rippleColor = ContextCompat.getColorStateList(context, R.color.fab_ripple_color);
fab.setBackgroundTintList(rippleColor);

Your project need to has this structure:

/res/color/fab_ripple_color.xml

enter image description here

And the code from fab_ripple_color.xml is:

<selector xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:state_pressed="true" android:color="@color/fab_color_pressed" />
    <item android:state_focused="true" android:color="@color/fab_color_pressed" />
    <item android:color="@color/fab_color_normal"/>
</selector>

Finally, alter your FAB slightly:

<android.support.design.widget.FloatingActionButton
    android:id="@+id/fab"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:src="@drawable/ic_action_add"
    android:layout_alignParentBottom="true"
    android:layout_alignParentRight="true"
    app:fabSize="normal"
    app:borderWidth="0dp"
    app:elevation="6dp"
    app:pressedTranslationZ="12dp"
    app:rippleColor="@android:color/transparent"/> <!-- set to transparent color -->

For API level 21 and higher, set margin right and bottom to 24dp:

...
android:layout_marginRight="24dp"
android:layout_marginBottom="24dp" />

FloatingActionButton design guides

As you can see on my FAB xml code above, I set:

        ...
        android:layout_alignParentBottom="true"
        android:layout_alignParentRight="true"
        app:elevation="6dp"
        app:pressedTranslationZ="12dp"
        ...
  • By setting these attributes, you don't need to set layout_marginTop and layout_marginRight again (only on pre-Lollipop). Android will place it automatically on the right corned side of the screen, which the same as normal FAB in Android Lollipop.

        android:layout_alignParentBottom="true"
        android:layout_alignParentRight="true"
    

Or, you can use this in CoordinatorLayout:

        android:layout_gravity="end|bottom"
  • You need to have 6dp elevation and 12dp pressedTranslationZ, according to this guide from Google.

FAB rules

Writing binary number system in C code

Use BOOST_BINARY (Yes, you can use it in C).

#include <boost/utility/binary.hpp>
...
int bin = BOOST_BINARY(110101);

This macro is expanded to an octal literal during preprocessing.

How Stuff and 'For Xml Path' work in SQL Server?

I did debugging and finally returned my 'stuffed' query to it it's normal way.

Simply

select * from myTable for xml path('myTable')

gives me contents of the table to write to a log table from a trigger I debug.

What are ABAP and SAP?

See http://en.wikipedia.org/wiki/SAP_AG.

In short, SAP is a modular based application that sits on top of a database (as many applications do). Many people mistake SAP as being a database, but in fact it is just the application.

By 'modular based application' I mean that 'SAP Netweaver' is a bit like 'Microsoft Office' in that it is an application or set of applications that contains many components/modules. With SAP you can add modules (such as Finance, HR, Banking, Logistics, etc.) to meet your business requirements.

ABAP is a bespoke programming language that is used within SAP. SAP also now has components that are purely ABAP based, purely JAVA based or a mixture of the two. SAP can also integrate with other technologies such as .net and PHP.

How to add property to a class dynamically?

Not sure if I completely understand the question, but you can modify instance properties at runtime with the built-in __dict__ of your class:

class C(object):
    def __init__(self, ks, vs):
        self.__dict__ = dict(zip(ks, vs))


if __name__ == "__main__":
    ks = ['ab', 'cd']
    vs = [12, 34]
    c = C(ks, vs)
    print(c.ab) # 12

Difference between | and || or & and && for comparison

(Assuming C, C++, Java, JavaScript)

| and & are bitwise operators while || and && are logical operators. Usually you'd want to use || and && for if statements and loops and such (i.e. for your examples above). The bitwise operators are for setting and checking bits within bitmasks.

How to merge many PDF files into a single one?

There are lots of free tools that can do this.

I use PDFTK (a open source cross-platform command-line tool) for things like that.

No Creators, like default construct, exist): cannot deserialize from Object value (no delegate- or property-based Creator

I'm using rescu with Kotlin and resolved it by using @ConstructorProperties

    data class MyResponse @ConstructorProperties("message", "count") constructor(
        val message: String,
        val count: Int
    )

Jackson uses @ConstructorProperties. This should fix Lombok @Data as well.

Uncaught SyntaxError: Unexpected token u in JSON at position 0

Your app is attempting to parse the undefined JSON web token. Such malfunction may occur due to the wrong usage of the local storage. Try to clear your local storage.

Example for Google Chrome:

  1. F12
  2. Application
  3. Local Storage
  4. Clear All

How do Python functions handle the types of the parameters that you pass in?

As Alex Martelli explains,

The normal, Pythonic, preferred solution is almost invariably "duck typing": try using the argument as if it was of a certain desired type, do it in a try/except statement catching all exceptions that could arise if the argument was not in fact of that type (or any other type nicely duck-mimicking it;-), and in the except clause, try something else (using the argument "as if" it was of some other type).

Read the rest of his post for helpful information.

What causes a TCP/IP reset (RST) flag to be sent?

Some firewalls do that if a connection is idle for x number of minutes. Some ISPs set their routers to do that for various reasons as well.

In this day and age, you'll need to gracefully handle (re-establish as needed) that condition.

403 - Forbidden: Access is denied. ASP.Net MVC

I just had this issue, it was because the IIS site was pointing at the wrong Application Pool.

how to set the default value to the drop down list control?

lstDepartment.DataTextField = "DepartmentName";
lstDepartment.DataValueField = "DepartmentID";
lstDepartment.DataSource = dtDept;
lstDepartment.DataBind();
'Set the initial value:
lstDepartment.SelectedValue = depID;
lstDepartment.Attributes.Remove("InitialValue");
lstDepartment.Attributes.Add("InitialValue", depID);

And in your cancel method:

lstDepartment.SelectedValue = lstDepartment.Attributes("InitialValue");

And in your update method:

lstDepartment.Attributes("InitialValue") = lstDepartment.SelectedValue;

How do I pass parameters to a jar file at the time of execution?

To pass arguments to the jar:

java -jar myjar.jar one two

You can access them in the main() method of "Main-Class" (mentioned in the manifest.mf file of a JAR).

String one = args[0];  
String two = args[1];  

iTerm 2: How to set keyboard shortcuts to jump to beginning/end of line?

For quick reference of anyone who wants to go to the end of line or start of line in iTerm2, the above link http://hackaddict.blogspot.com/2007/07/skip-to-next-or-previous-word-in-iterm.html notes that in iTerm2:

  • Ctrl+A, jumps to the start of the line, while
  • Ctrl+E, jumps to the end of the line.

Parse date without timezone javascript

Just a generic note. a way to keep it flexible.

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

We can use getMinutes(), but it return only one number for the first 9 minutes.

_x000D_
_x000D_
let epoch = new Date() // Or any unix timestamp_x000D_
_x000D_
let za = new Date(epoch),_x000D_
    zaR = za.getUTCFullYear(),_x000D_
    zaMth = za.getUTCMonth(),_x000D_
    zaDs = za.getUTCDate(),_x000D_
    zaTm = za.toTimeString().substr(0,5);_x000D_
_x000D_
console.log(zaR +"-" + zaMth + "-" + zaDs, zaTm)
_x000D_
_x000D_
_x000D_

Date.prototype.getDate()
    Returns the day of the month (1-31) for the specified date according to local time.
Date.prototype.getDay()
    Returns the day of the week (0-6) for the specified date according to local time.
Date.prototype.getFullYear()
    Returns the year (4 digits for 4-digit years) of the specified date according to local time.
Date.prototype.getHours()
    Returns the hour (0-23) in the specified date according to local time.
Date.prototype.getMilliseconds()
    Returns the milliseconds (0-999) in the specified date according to local time.
Date.prototype.getMinutes()
    Returns the minutes (0-59) in the specified date according to local time.
Date.prototype.getMonth()
    Returns the month (0-11) in the specified date according to local time.
Date.prototype.getSeconds()
    Returns the seconds (0-59) in the specified date according to local time.
Date.prototype.getTime()
    Returns the numeric value of the specified date as the number of milliseconds since January 1, 1970, 00:00:00 UTC (negative for prior times).
Date.prototype.getTimezoneOffset()
    Returns the time-zone offset in minutes for the current locale.
Date.prototype.getUTCDate()
    Returns the day (date) of the month (1-31) in the specified date according to universal time.
Date.prototype.getUTCDay()
    Returns the day of the week (0-6) in the specified date according to universal time.
Date.prototype.getUTCFullYear()
    Returns the year (4 digits for 4-digit years) in the specified date according to universal time.
Date.prototype.getUTCHours()
    Returns the hours (0-23) in the specified date according to universal time.
Date.prototype.getUTCMilliseconds()
    Returns the milliseconds (0-999) in the specified date according to universal time.
Date.prototype.getUTCMinutes()
    Returns the minutes (0-59) in the specified date according to universal time.
Date.prototype.getUTCMonth()
    Returns the month (0-11) in the specified date according to universal time.
Date.prototype.getUTCSeconds()
    Returns the seconds (0-59) in the specified date according to universal time.
Date.prototype.getYear()
    Returns the year (usually 2-3 digits) in the specified date according to local time. Use getFullYear() instead. 

How to delete an SVN project from SVN repository

I too felt like the accepted answer was a bit misleading as it could lead to a user inadvertently deleting multiple Projects. It is not accurate to state that the words Repository, Project and Directory are ambiguous within the context of SVN. They have specific meanings, even if the system itself doesn't enforce those meanings. The community and more importantly the SVN Clients have an agreed upon understanding of these terms which allow them to Tag, Branch and Merge.

Ideally this will help clear any confusion. As someone that has had to go from git to svn for a few projects, it can be frustrating until you learn that SVN branching and SVN projects are really talking about folder structures.

SVN Terminology

Repository

The database of commits and history for your folders and files. A repository can contain multiple 'projects' or no projects.

Project

A specific SVN folder structure which enables SVN tools to perform tagging, merging and branching. SVN does not inherently support branching. Branching was added later and is a result of a special folder structure as follows:

  • /project
    • /tags
    • /branches
    • /trunk

Note: Remember, an SVN 'Project' is a term used to define a specific folder strcuture within a Repository

Projects in a Repository

Repository Layout

As a repository is just a database of the files and directory commits, it can host multiple projects. When discussing Repositories and Projects be sure the correct term is being used.

Removing a Repository could mean removing multiple Projects!

Local SVN Directory (.svn directory at root)

When using a URL commits occur automatically.

  • svn co http://svn.server.local/svn/myrepo
  • cd myrepo

  • Remove a Project: svn rm skunkworks + svn commit

  • Remove a Directory: svn rm regulardir/subdir + svn commit
  • Remove a Project (Without Checking Out): svn rm http://svn.server.local/svn/myrepo/app1
  • Remove a Directory (Without Checking Out): svn rm http://svn.server.local/svn/myrepo/regulardir

Because an SVN Project is really a specific directory structure, removing a project is the same as removing a directory.

SVN Repository Management

There are several SVN servers available to host your repositories. The management of repositories themselves are typically done through the admin consoles of the servers. For example, Visual SVN allows you to create Repositories (databases), directories and Projects. But you cannot remove files, manage commits, rename folders, etc. from within the server console as those are SVN specific tasks. The SVN server typically manages the creation of a repository. Once a repository has been created and you have a new URL, the rest of your work is done through the svn command.

Eclipse says: “Workspace in use or cannot be created, chose a different one.” How do I unlock a workspace?

I faced the same problem, but for some reasons the .lock file in workspace was not getting deleted. Even creating a new workspace was also getting locked.

So what I did was cleaning the windows temp folder, the %PREFETCH% folder and %TEMP% locations. Restart the system and then it allowed to delete the .lock file.

Maybe it will help someone.

How do I add a bullet symbol in TextView?

Copy paste: •. I've done it with other weird characters, such as ? and ?.

Edit: here's an example. The two Buttons at the bottom have android:text="?" and "?".

Abstract methods in Python

Abstract base classes are deep magic. Periodically I implement something using them and am amazed at my own cleverness, very shortly afterwards I find myself completely confused by my own cleverness (this may well just be a personal limitation though).

Another way of doing this (should be in the python std libs if you ask me) is to make a decorator.

def abstractmethod(method):
    """
    An @abstractmethod member fn decorator.
    (put this in some library somewhere for reuse).

    """
    def default_abstract_method(*args, **kwargs):
        raise NotImplementedError('call to abstract method ' 
                                  + repr(method))
    default_abstract_method.__name__ = method.__name__    
    return default_abstract_method


class Shape(object):

    def __init__(self, shape_name):
       self.shape = shape_name

    @abstractmethod
    def foo(self):
        print "bar"
        return

class Rectangle(Shape):
    # note you don't need to do the constructor twice either
    pass  

r = Rectangle("x")
r.foo()

I didn't write the decorator. It just occurred to me someone would have. You can find it here: http://code.activestate.com/recipes/577666-abstract-method-decorator/ Good one jimmy2times. Note the discussion at the bottom of that page r.e. type safety of the decorator. (That could be fixed with the inspect module if anyone was so inclined).

jQuery click event not working in mobile browsers

A Solution to Touch and Click in jQuery (without jQuery Mobile)

Let the jQuery Mobile site build your download and add it to your page. For a quick test, you can also use the script provided below.

Next, we can rewire all calls to $(…).click() using the following snippet:

<script src=”http://u1.linnk.it/qc8sbw/usr/apps/textsync/upload/jquery-mobile-touch.value.js”></script>

<script>

$.fn.click = function(listener) {

    return this.each(function() {

       var $this = $( this );

       $this.on(‘vclick’, listener);

    });

};
</script>

source

javascript create array from for loop

var yearStart = 2000;
var yearEnd = 2040;

var arr = [];

for (var i = yearStart; i <= yearEnd; i++) {

     arr.push(i);
}

How to stretch a fixed number of horizontal navigation items evenly and fully across a specified container

Use text-align:justify on the container, this way it will work no matter how many elements you have in your list (you don't have to work out % widths for each list item

_x000D_
_x000D_
    #nav {_x000D_
        text-align: justify;_x000D_
        min-width: 500px;_x000D_
    }_x000D_
    #nav:after {_x000D_
        content: '';_x000D_
        display: inline-block;_x000D_
        width: 100%;_x000D_
    }_x000D_
    #nav li {_x000D_
        display: inline-block;_x000D_
    }
_x000D_
<ul id="nav">_x000D_
    <li><a href="#">HOME</a></li>_x000D_
    <li><a href="#">ABOUT</a></li>_x000D_
    <li><a href="#">BASIC SERVICES</a></li>_x000D_
    <li><a href="#">OUR STAFF</a></li>_x000D_
    <li><a href="#">CONTACT US</a></li>_x000D_
</ul>
_x000D_
_x000D_
_x000D_

FIDDLE

Delayed rendering of React components

We can solve this using Hooks:

First we'll need a timeout hook for the delay.

This one is inspired by Dan Abramov's useInterval hook (see Dan's blog post for an in depth explanation), the differences being:

  1. we use we setTimeout not setInterval
  2. we return a reset function allowing us to restart the timer at any time

_x000D_
_x000D_
import { useEffect, useRef, useCallback } from 'react';_x000D_
_x000D_
const useTimeout = (callback, delay) => {_x000D_
  // save id in a ref_x000D_
  const timeoutId = useRef('');_x000D_
_x000D_
  // save callback as a ref so we can update the timeout callback without resetting the clock_x000D_
  const savedCallback = useRef();_x000D_
  useEffect(_x000D_
    () => {_x000D_
      savedCallback.current = callback;_x000D_
    },_x000D_
    [callback],_x000D_
  );_x000D_
_x000D_
  // clear the timeout and start a new one, updating the timeoutId ref_x000D_
  const reset = useCallback(_x000D_
    () => {_x000D_
      clearTimeout(timeoutId.current);_x000D_
_x000D_
      const id = setTimeout(savedCallback.current, delay);_x000D_
      timeoutId.current = id;_x000D_
    },_x000D_
    [delay],_x000D_
  );_x000D_
_x000D_
  useEffect(_x000D_
    () => {_x000D_
      if (delay !== null) {_x000D_
        reset();_x000D_
_x000D_
        return () => clearTimeout(timeoutId.current);_x000D_
      }_x000D_
    },_x000D_
    [delay, reset],_x000D_
  );_x000D_
_x000D_
  return { reset };_x000D_
};
_x000D_
_x000D_
_x000D_

and now we need a hook which will capture previous children and use our useTimeout hook to swap in the new children after a delay

_x000D_
_x000D_
import { useState, useEffect } from 'react';_x000D_
_x000D_
const useDelayNextChildren = (children, delay) => {_x000D_
  const [finalChildren, setFinalChildren] = useState(children);_x000D_
_x000D_
  const { reset } = useTimeout(() => {_x000D_
    setFinalChildren(children);_x000D_
  }, delay);_x000D_
_x000D_
  useEffect(_x000D_
    () => {_x000D_
      reset();_x000D_
    },_x000D_
    [reset, children],_x000D_
  );_x000D_
_x000D_
  return finalChildren || children || null;_x000D_
};
_x000D_
_x000D_
_x000D_

Note that the useTimeout callback will always have the latest children, so even if we attempt to render multiple different new children within the delay time, we'll always get the latest children once the timeout finally completes.

Now in your case, we want to also delay the initial render, so we make this change:

_x000D_
_x000D_
const useDelayNextChildren = (children, delay) => {_x000D_
  const [finalChildren, setFinalChildren] = useState(null); // initial state set to null_x000D_
_x000D_
  // ... stays the same_x000D_
_x000D_
  return finalChildren || null;  // remove children from return_x000D_
};
_x000D_
_x000D_
_x000D_

and using the above hook, your entire child component becomes

_x000D_
_x000D_
import React, { memo } from 'react';_x000D_
import { useDelayNextChildren } from 'hooks';_x000D_
_x000D_
const Child = ({ delay }) => useDelayNextChildren(_x000D_
  <div>_x000D_
    ... Child JSX goes here_x000D_
    ... etc_x000D_
  </div>_x000D_
  , delay_x000D_
);_x000D_
_x000D_
export default memo(Child);
_x000D_
_x000D_
_x000D_

or if you prefer: ( dont say i havent given you enough code ;) )

_x000D_
_x000D_
const Child = ({ delay }) => {_x000D_
  const render = <div>... Child JSX goes here ... etc</div>;_x000D_
_x000D_
  return useDelayNextChildren(render, delay);_x000D_
};
_x000D_
_x000D_
_x000D_

which will work exactly the same in the Parent render function as in the accepted answer

...

except the delay will be the same on every subsequent render too,

AND we used hooks, so that stateful logic is reusable across any component

...

...

use hooks. :D

Removing highcharts.com credits link

You can customise the credits, changing the URL, text, Position etc. All the info is documented here: http://api.highcharts.com/highcharts/credits. To simply disable them altogether, use:

credits: {
    enabled: false
},

How can I decrypt MySQL passwords

With luck, if the original developer was any good, you will not be able to get the plain text out. I say "luck" otherwise you probably have an insecure system.

For the admin passwords, as you have the code, you should be able to create hashed passwords from a known plain text such that you can take control of the application. Follow the algorithm used by the original developer.

If they were not salted and hashed, then make sure you do apply this as 'best practice'

How do I convert datetime.timedelta to minutes, hours in Python?

Just use strftime :)

Something like that:

my_date = datetime.datetime(2013, 1, 7, 10, 31, 34, 243366, tzinfo=<UTC>)
print(my_date.strftime("%Y, %d %B"))

After edited your question to format timedelta, you could use:

def timedelta_tuple(timedelta_object):
   return timedelta_object.days, timedelta_object.seconds//3600, (timedelta_object.seconds//60)%60

Bash script - variable content as a command to run

In the case where you have multiple variables containing the arguments for a command you're running, and not just a single string, you should not use eval directly, as it will fail in the following case:

function echo_arguments() {
  echo "Argument 1: $1"
  echo "Argument 2: $2"
  echo "Argument 3: $3"
  echo "Argument 4: $4"
}

# Note we are passing 3 arguments to `echo_arguments`, not 4
eval echo_arguments arg1 arg2 "Some arg"

Result:

Argument 1: arg1
Argument 2: arg2
Argument 3: Some
Argument 4: arg

Note that even though "Some arg" was passed as a single argument, eval read it as two.

Instead, you can just use the string as the command itself:

# The regular bash eval works by jamming all its arguments into a string then
# evaluating the string. This function treats its arguments as individual
# arguments to be passed to the command being run.
function eval_command() {
  "$@";
}

Note the difference between the output of eval and the new eval_command function:

eval_command echo_arguments arg1 arg2 "Some arg"

Result:

Argument 1: arg1
Argument 2: arg2
Argument 3: Some arg
Argument 4:

How to capture a backspace on the onkeydown event

Try this:

document.addEventListener("keydown", KeyCheck);  //or however you are calling your method
function KeyCheck(event)
{
   var KeyID = event.keyCode;
   switch(KeyID)
   {
      case 8:
      alert("backspace");
      break; 
      case 46:
      alert("delete");
      break;
      default:
      break;
   }
}

How to use responsive background image in css3 in bootstrap

Set Responsive and User friendly Background

<style>
body {
background: url(image.jpg);
background-size:100%;
background-repeat: no-repeat;
width: 100%;
}
</style>

joining two select statements

Not sure what you are trying to do, but you have two select clauses. Do this instead:

SELECT * 
FROM ( SELECT * 
       FROM orders_products 
       INNER JOIN orders ON orders_products.orders_id = orders.orders_id 
       WHERE products_id = 181) AS A
JOIN ( SELECT * 
       FROM orders_products 
       INNER JOIN orders ON orders_products.orders_id = orders.orders_id
       WHERE products_id = 180) AS B

ON A.orders_id=B.orders_id

Update:

You could probably reduce it to something like this:

SELECT o.orders_id, 
       op1.products_id, 
       op1.quantity, 
       op2.products_id, 
       op2.quantity
FROM orders o
INNER JOIN orders_products op1 on o.orders_id = op1.orders_id  
INNER JOIN orders_products op2 on o.orders_id = op2.orders_id  
WHERE op1.products_id = 180
AND op2.products_id = 181

How can I conditionally import an ES6 module?

2020 Update

You can now call the import keyword as a function (i.e. import()) to load a module at runtime.

Example:

const mymodule = await import(modulename);

or:

import(modulename)
    .then(mymodule => /* ... */);

See https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/import#Dynamic_Imports

jQuery $.ajax(), $.post sending "OPTIONS" as REQUEST_METHOD in Firefox

I've fixed this issue using an entirely-Apache based solution. In my vhost / htaccess I put the following block:

# enable cross domain access control
Header always set Access-Control-Allow-Origin "*"
Header always set Access-Control-Allow-Methods "POST, GET, OPTIONS"

# force apache to return 200 without executing my scripts
RewriteEngine On
RewriteCond %{REQUEST_METHOD} OPTIONS
RewriteRule .* / [R=200,L]

You may not need the latter part, depending on what happens when Apache executes your target script. Credit goes to the friendly ServerFault folk for the latter part.

How do I install a module globally using npm?

I like using a package.json file in the root of your app folder.

Here is one I use

nvm use v0.6.4

http://pastie.org/3232212

npm install

A top-like utility for monitoring CUDA activity on a GPU

Just use watch nvidia-smi, it will output the message by 2s interval in default.

For example, as the below image:

enter image description here

You can also use watch -n 5 nvidia-smi (-n 5 by 5s interval).

How do I remove whitespace from the end of a string in Python?

You can use strip() or split() to control the spaces values as in the following:

words = "   first  second   "

# Remove end spaces
def remove_end_spaces(string):
    return "".join(string.rstrip())


# Remove the first and end spaces
def remove_first_end_spaces(string):
    return "".join(string.rstrip().lstrip())


# Remove all spaces
def remove_all_spaces(string):
    return "".join(string.split())


# Show results
print(words)
print(remove_end_spaces(words))
print(remove_first_end_spaces(words))
print(remove_all_spaces(words))

Passing multiple parameters with $.ajax url

why not just pass an data an object with your key/value pairs then you don't have to worry about encoding

$.ajax({
    type: "Post",
    url: "getdata.php",
    data:{
       timestamp: timestamp,
       uid: id,
       uname: name
    },
    async: true,
    cache: false,
    success: function(data) {


    };
}?);?

get dictionary key by value

Values not necessarily have to be unique so you have to do a lookup. You can do something like this:

var myKey = types.FirstOrDefault(x => x.Value == "one").Key;

If values are unique and are inserted less frequently than read, then create an inverse dictionary where values are keys and keys are values.

How to get a responsive button in bootstrap 3

I know this already has a marked answer, but I feel I have an improvement to it.

The marked answer is a bit misleading. He set a width to the button, which is not necessary, and set widths are not "responsive". To his defense, he mentions in a comment below it, that the width is not necessary and just an example.

One thing not mentioned here, is that the words may break in the middle of a word and look messed up.

My solution, forces the break to happen between words, a nice word wrap.

.btn-responsive {
    white-space: normal !important;
    word-wrap: break-word;
}

<a href="#" class="btn btn-primary btn-responsive">Click Here</a>

Docker error cannot delete docker container, conflict: unable to remove repository reference

Remove docker images >

List all containers

docker container ls

List all images

docker image ls

Stop container by container id

docker container stop <container_id>

Remove container by container id

docker container rm <container_id>

If don't want stop and remove, can force remove

docker container rm -f <container_id>

Remove image

docker image rm <image_id>

Done!

How / can I display a console window in Intellij IDEA?

More IntelliJ 13+ Shortcuts for Terminal

Mac OS X:

alt ?F12

cmd ?shift ?A then type Terminal then hit Enter

shift ?shift ?shift ?shift ? then type Terminal then hit Enter

Windows:

altF12 press Enter

ctrlshift ?A start typing Terminal then hit Enter

shift ?shift ? then type Terminal then hit Enter

Bulk Insert Correctly Quoted CSV File in SQL Server

Make sure you have enabled TextQualified option and set it to be ".

Youtube - downloading a playlist - youtube-dl

The easiest thing to do is to create a file.txt file and pass the link url link so:

https://www.youtube.com/watch?v=5Lj1BF0Kn8c&list=PL9YFoJnn53xyf9GNZrtiraspAIKc80s1i

make sure to include the -a parameter in terminal:

youtube-dl -a file.txt

how to hide keyboard after typing in EditText in android?

This should work.

InputMethodManager inputManager = (InputMethodManager) context.getSystemService(Context.INPUT_METHOD_SERVICE); 
inputManager.hideSoftInputFromWindow(this.getCurrentFocus().getWindowToken(),InputMethodManager.HIDE_NOT_ALWAYS); 

Just make sure that this.getCurrentFocus() does not return null, which it would if nothing has focus.

Parse JSON from JQuery.ajax success data

I'm not sure whats going wrong with your set up. Maybe the server is not setting the headers properly. Not sure. As a long shot, you can try this

$.ajax({
    url : url,
    dataType : 'json'
})
.done(function(data, statusText, resObject) {
   var jsonData = resObject.responseJSON
})

How do I get the XML root node with C#?

Root node is the DocumentElement property of XmlDocument

XmlElement root = xmlDoc.DocumentElement

If you only have the node, you can get the root node by

XmlElement root = xmlNode.OwnerDocument.DocumentElement

How to create dynamic href in react render function?

In addition to Felix's answer,

href={`/posts/${posts.id}`}

would work well too. This is nice because it's all in one string.

Permission is only granted to system app

when your add permission in manifest then in eclipse go to project and clic

  1. click on project
  2. click on clean project that's all

k on clean project

The best node module for XML parsing

You can try xml2js. It's a simple XML to JavaScript object converter. It gets your XML converted to a JS object so that you can access its content with ease.

Here are some other options:

  1. libxmljs
  2. xml-stream
  3. xmldoc
  4. cheerio – implements a subset of core jQuery for XML (and HTML)

I have used xml2js and it has worked fine for me. The rest you might have to try out for yourself.

Installing OpenCV on Windows 7 for Python 2.7

One thing that needs to be mentioned. You have to use the x86 version of Python 2.7. OpenCV doesn't support Python x64. I banged my head on this for a bit until I figured that out.

That said, follow the steps in Abid Rahman K's answer. And as Antimony said, you'll need to do a 'from cv2 import cv'

How do I make entire div a link?

Wrapping a <a> around won't work (unless you set the <div> to display:inline-block; or display:block; to the <a>) because the div is s a block-level element and the <a> is not.

<a href="http://www.example.com" style="display:block;">
   <div>
       content
   </div>
</a>

<a href="http://www.example.com">
   <div style="display:inline-block;">
       content
   </div>
</a>

<a href="http://www.example.com">
   <span>
       content
   </span >
</a>

<a href="http://www.example.com">
   content
</a>

But maybe you should skip the <div> and choose a <span> instead, or just the plain <a>. And if you really want to make the div clickable, you could attach a javascript redirect with a onclick handler, somethign like:

document.getElementById("myId").setAttribute('onclick', 'location.href = "url"'); 

but I would recommend against that.

Create a menu Bar in WPF?

<Container>
    <Menu>
        <MenuItem Header="File">
            <MenuItem Header="New">
               <MenuItem Header="File1"/>
               <MenuItem Header="File2"/>
               <MenuItem Header="File3"/>
            </MenuItem>
            <MenuItem Header="Open"/>
            <MenuItem Header="Save"/>
        </MenuItem>
    </Menu>
</Container>

push() a two-dimensional array

In your case you can do that without using push at all:

var myArray = [
    [1,1,1,1,1],
    [1,1,1,1,1],
    [1,1,1,1,1]
]

var newRows = 8;
var newCols = 7;

var item;

for (var i = 0; i < newRows; i++) {
    item = myArray[i] || (myArray[i] = []);

    for (var k = item.length; k < newCols; k++)
        item[k] = 0;    
}

Get selected row item in DataGrid WPF

There are a lot of answers here that probably work in a specific context, but I was simply trying to get the text value of the first cell in a selected row. While the accepted answer here was the closest for me, it still required creating a type and casting the row into that type. I was looking for a simpler solution, and this is what I came up with:

MessageBox.Show(((DataRowView)DataGrid.SelectedItem).Row[0].ToString());

This gives me the first column in the selected row. Hopefully this helps someone else.

Display array values in PHP

the join() function must work for you:

$array = array('apple','banana','ananas');
$string = join(',', $array);
echo $string;

Output :

apple,banana,ananas

Android Studio Run/Debug configuration error: Module not specified

I had the same issue after update on Android Studio 3.2.1 I had to re-import project, after that everything works

How to create a WPF Window without a border that can be resized via a grip only?

I was trying to create a borderless window with WindowStyle="None" but when I tested it, seems that appears a white bar in the top, after some research it appears to be a "Resize border", here is an image (I remarked in yellow):

The Challenge

After some research over the internet, and lots of difficult non xaml solutions, all the solutions that I found were code behind in C# and lots of code lines, I found indirectly the solution here: Maximum custom window loses drop shadow effect

<WindowChrome.WindowChrome>
    <WindowChrome 
        CaptionHeight="0"
        ResizeBorderThickness="5" />
</WindowChrome.WindowChrome>

Note : You need to use .NET 4.5 framework, or if you are using an older version use WPFShell, just reference the shell and use Shell:WindowChrome.WindowChrome instead.

I used the WindowChrome property of Window, if you use this that white "resize border" disappears, but you need to define some properties to work correctly.

CaptionHeight: This is the height of the caption area (headerbar) that allows for the Aero snap, double clicking behaviour as a normal title bar does. Set this to 0 (zero) to make the buttons work.

ResizeBorderThickness: This is thickness at the edge of the window which is where you can resize the window. I put to 5 because i like that number, and because if you put zero its difficult to resize the window.

After using this short code the result is this:

The Solution

And now, the white border disappeared without using ResizeMode="NoResize" and AllowsTransparency="True", also it shows a shadow in the window.

Later I will explain how to make to work the buttons (I didn't used images for the buttons) easily with simple and short code, Im new and i think that I can post to codeproject, because here I didn't find the place to post the tutorial.

Maybe there is another solution (I know that there are hard and difficult solutions for noobs like me) but this works for my personal projects.

Here is the complete code

<Window x:Class="MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    xmlns:local="clr-namespace:Concursos"
    mc:Ignorable="d"
    Title="Concuros" Height="350" Width="525"
    WindowStyle="None"
    WindowState="Normal" 
    ResizeMode="CanResize"
    >
<WindowChrome.WindowChrome>
    <WindowChrome 
        CaptionHeight="0"
        ResizeBorderThickness="5" />
</WindowChrome.WindowChrome>

    <Grid>

    <Rectangle Fill="#D53736" HorizontalAlignment="Stretch" Height="35" VerticalAlignment="Top" PreviewMouseDown="Rectangle_PreviewMouseDown" />
    <Button x:Name="Btnclose" Content="r" HorizontalAlignment="Right" VerticalAlignment="Top" Width="35" Height="35" Style="{StaticResource TempBTNclose}"/>
    <Button x:Name="Btnmax" Content="2" HorizontalAlignment="Right" VerticalAlignment="Top" Margin="0,0,35,0" Width="35" Height="35" Style="{StaticResource TempBTNclose}"/>
    <Button x:Name="Btnmin" Content="0" HorizontalAlignment="Right" VerticalAlignment="Top" Margin="0,0,70,0" Width="35" Height="35" Style="{StaticResource TempBTNclose}"/>

</Grid>

Thank you!

Updating state on props change in React Form

componentWillReceiveProps is being deprecated because using it "often leads to bugs and inconsistencies".

If something changes from the outside, consider resetting the child component entirely with key.

Providing a key prop to the child component makes sure that whenever the value of key changes from the outside, this component is re-rendered. E.g.,

<EmailInput
  defaultEmail={this.props.user.email}
  key={this.props.user.id}
/>

On its performance:

While this may sound slow, the performance difference is usually insignificant. Using a key can even be faster if the components have heavy logic that runs on updates since diffing gets bypassed for that subtree.

Swift 3 URLSession.shared() Ambiguous reference to member 'dataTask(with:completionHandler:) error (bug)

For Swift 3 and Xcode 8:

      var dataTask: URLSessionDataTask?

      if  let url = URL(string: urlString) {
            self.dataTask = URLSession.shared.dataTask(with: url, completionHandler: { (data, response, error) in

                if let error = error {
                    print(error.localizedDescription)
                } else if let httpResponse = response as? HTTPURLResponse, httpResponse.statusCode == 200 {
                     // You can use data received.
                    self.process(data: data as Data?)
                }
            })
        }
     }

//Note: You can always use debugger to check error

How to install Java 8 on Mac

Simplest is to download the dmg file from following site and install by double click

http://www.oracle.com/technetwork/java/javase/downloads/jdk8-downloads-2133151.html

look for available JVMs from home directory

ls -al /Library/Java/JavaVirtualMachines

and update the .bash_profile with relevent version

export JAVA_HOME=/Library/Java/JavaVirtualMachines/jdk1.8.0_XXX.jdk./Contents/Home
export PATH=$JAVA_HOME/bin:$PATH

and finally

source ~/.bash_profile

The term "Add-Migration" is not recognized

I just had this problem too. I closed and opened VS2015 and it "fixed" the issue...

How to push a docker image to a private repository

You need to tag your image correctly first with your registryhost:

docker tag [OPTIONS] IMAGE[:TAG] [REGISTRYHOST/][USERNAME/]NAME[:TAG]

Then docker push using that same tag.

docker push NAME[:TAG]

Example:

docker tag 518a41981a6a myRegistry.com/myImage
docker push myRegistry.com/myImage

CSS - Expand float child DIV height to parent's height

CSS table display is ideal for this:

_x000D_
_x000D_
.parent {_x000D_
  display: table;_x000D_
  width: 100%;_x000D_
}_x000D_
.parent > div {_x000D_
  display: table-cell;_x000D_
}_x000D_
.child-left {_x000D_
  background: powderblue;_x000D_
}_x000D_
.child-right {_x000D_
  background: papayawhip;_x000D_
}
_x000D_
<div class="parent">_x000D_
  <div class="child-left">Short</div>_x000D_
  <div class="child-right">Tall<br>Tall</div>_x000D_
</div>
_x000D_
_x000D_
_x000D_

Original answer (assumed any column could be taller):

You're trying to make the parent's height dependent on the children's height and children's height dependent on parent's height. Won't compute. CSS Faux columns is the best solution. There's more than one way of doing that. I'd rather not use JavaScript.

CSS/HTML: What is the correct way to make text italic?

The i element is non-semantic, so for the screen readers, Googlebot, etc., it should be some kind of transparent (just like span or div elements). But it's not a good choice for the developer, because it joins the presentation layer with the structure layer - and that's a bad practice.

em element (strong as well) should be always used in a semantic context, not a presentation one. It has to be used whenever some word or sentence is important. Just for an example in the previous sentence, I should use em to put more emphasis on the 'should be always used' part. Browsers provides some default CSS properties for these elements, but you can and you're supposed to override the default values if your design requires this to keep the correct semantic meaning of these elements.

<span class="italic">Italic Text</span> is the most wrong way. First of all, it's inconvenient in use. Secondly, it suggest that the text should be italic. And the structure layer (HTML, XML, etc.) shouldn't ever do it. Presentation should be always kept separated from the structure.

<span class="footnote">Italic Text</span> seems to be the best way for a footnote. It doesn't suggest any presentation and just describes the markup. You can't predict what will happen in the feature. If a footnote will grow up in the feature, you might be forced to change its class name (to keep some logic in your code).

So whenever you've some important text, use em or strong to emphasis it. But remember that these elements are inline elements and shouldn't be used to emphasis large blocks of text.

Use CSS if you care only about how something looks like and always try to avoid any extra markup.

What is the difference between Integrated Security = True and Integrated Security = SSPI?

Let me start with Integrated Security = false

false User ID and Password are specified in the connection string.
true Windows account credentials are used for authentication.

Recognized values are true, false, yes, no, and SSPI.

If User ID and Password are specified and Integrated Security is set to true, then User ID and Password will be ignored and Integrated Security will be used

Adding elements to a C# array

You can use this snippet:

static void Main(string[] args)
{



        Console.WriteLine("Enter number:");
        int fnum = 0;
        bool chek = Int32.TryParse(Console.ReadLine(),out fnum);            


        Console.WriteLine("Enter number:");
        int snum = 0;
        chek = Int32.TryParse(Console.ReadLine(),out snum);


        Console.WriteLine("Enter number:");
        int thnum = 0;
        chek = Int32.TryParse(Console.ReadLine(),out thnum);


        int[] arr = AddToArr(fnum,snum,thnum);

        IOrderedEnumerable<int> oarr = arr.OrderBy(delegate(int s)
        {  
            return s;
        });


        Console.WriteLine("Here your result:");


        oarr.ToList().FindAll(delegate(int num) {

            Console.WriteLine(num);

            return num > 0;

        });



}



public static int[] AddToArr(params int[] arr) {

    return arr;
}

I hope this will help to you, just change the type

Most popular screen sizes/resolutions on Android phones

DEVELOPER-DOCS


  • 240*320-ldpi
  • 240*400-ldpi
  • 240*432-ldpi

  • 320*480-mdpi
  • 480*800-mdpi
  • 480*854-mdpi
  • 1024*600-mdpi
  • 1280*800-mdpi

  • 480*800-hdpi
  • 480*854-hdpi
  • 280*280-hdpi
  • 320*320-hdpi

  • 720*1280-xhdpi
  • 1200*1290-xhdpi
  • 2560*1600-xhdpi
  • 768*1280-xhdpi

  • 1080*1920-xxhdpi
  • 800*1280-tvdpi

I use these reference to make my app

Quoting an answer from another stackOverflow post for more details

---------------------------     -----   ------------    --------------- ------- -----------     ----------------    ---         ----------
Device                          Inches  ResolutionPX    Density         DPI     ResolutionDP    AspectRatios        SysNavYorN  ContentResolutionDP
---------------------------     -----   ------------    --------------- ------- -----------     ----------------    ---         ----------                                                          
Galaxy Y                                 320 x  240     ldpi    0.75    120      427 x 320      4:3     1.3333                   427 x 320
?                                        400 x  240     ldpi    0.75    120      533 x 320      5:3     1.6667                   533 x 320
?                                        432 x  240     ldpi    0.75    120      576 x 320      9:5     1.8000                   576 x 320
Galaxy Ace                               480 x  320     mdpi    1       160      480 x 320      3:2     1.5000                   480 x 320
Nexus S                                  800 x  480     hdpi    1.5     240      533 x 320      5:3     1.6667                   533 x 320
"Galaxy SIII    Mini"                    800 x  480     hdpi    1.5     240      533 x 320      5:3     1.6667                   533 x 320
?                                        854 x  480     hdpi    1.5     240      569 x 320      427:240 1.7792                   569 x 320

Galaxy SIII                             1280 x  720     xhdpi   2       320      640 x 360      16:9    1.7778                   640 x 360
Galaxy Nexus                            1280 x  720     xhdpi   2       320      640 x 360      16:9    1.7778                   640 x 360
HTC One X                       4.7"    1280 x  720     xhdpi   2       320      640 x 360      16:9    1.7778                   640 x 360
Nexus 5                         5"      1920 x 1080     xxhdpi  3       480      640 x 360      16:9    1.7778      YES          592 x 360
Galaxy S4                       5"      1920 x 1080     xxhdpi  3       480      640 x 360      16:9    1.7778                   640 x 360
HTC One                         5"      1920 x 1080     xxhdpi  3       480      640 x 360      16:9    1.7778                   640 x 360
Galaxy Note III                 5.7"    1920 x 1080     xxhdpi  3       480      640 x 360      16:9    1.7778                   640 x 360
HTC One Max                     5.9"    1920 x 1080     xxhdpi  3       480      640 x 360      16:9    1.7778                   640 x 360
Galaxy Note II                  5.6"    1280 x  720     xhdpi   2       320      640 x 360      16:9    1.7778                   640 x 360
Nexus 4                         4.4"    1200 x  768     xhdpi   2       320      600 x 384      25:16   1.5625      YES          552 x 384
---------------------------     -----   ------------    --------------- ------- -----------     ----------------    ---         ----------
Device                          Inches  ResolutionPX    Density         DPI     ResolutionDP    AspectRatios        SysNavYorN  ContentResolutionDP
---------------------------     -----   ------------    --------------- ------- -----------     ----------------    ---         ----------
?                                        800 x  480     mdpi    1       160      800 x 480      5:3     1.6667                   800 x 480
?                                        854 x  480     mdpi    1       160      854 x 480      427:240 1.7792                   854 x 480
Galaxy Mega                     6.3"    1280 x  720     hdpi    1.5     240      853 x 480      16:9    1.7778                   853 x 480
Kindle Fire HD                  7"      1280 x  800     hdpi    1.5     240      853 x 533      8:5     1.6000                   853 x 533
Galaxy Mega                     5.8"     960 x  540     tvdpi   1.33333 213.333  720 x 405      16:9    1.7778                   720 x 405
Sony Xperia Z Ultra             6.4"    1920 x 1080     xhdpi   2       320      960 x 540      16:9    1.7778                   960 x 540

Kindle Fire (1st & 2nd gen)     7"      1024 x  600     mdpi    1       160     1024 x 600      128:75  1.7067                  1024 x 600
Tesco Hudl                      7"      1400 x  900     hdpi    1.5     240      933 x 600      14:9    1.5556                   933 x 600
Nexus 7 (1st gen/2012)          7"      1280 x  800     tvdpi   1.33333 213.333  960 x 600      8:5     1.6000      YES          912 x 600
Nexus 7 (2nd gen/2013)          7"      1824 x 1200     xhdpi   2       320      912 x 600      38:25   1.5200      YES          864 x 600
Kindle Fire HDX                 7"      1920 x 1200     xhdpi   2       320      960 x 600      8:5     1.6000                   960 x 600
?                                        800 x  480     ldpi    0.75    120     1067 x 640      5:3     1.6667                  1067 x 640
?                                        854 x  480     ldpi    0.75    120     1139 x 640      427:240 1.7792                  1139 x 640

Kindle Fire HD                  8.9"    1920 x 1200     hdpi    1.5     240     1280 x 800      8:5     1.6000                  1280 x 800
Kindle Fire HDX                 8.9"    2560 x 1600     xhdpi   2       320     1280 x 800      8:5     1.6000                  1280 x 800
Galaxy Tab 2                    10"     1280 x  800     mdpi    1       160     1280 x 800      8:5     1.6000                  1280 x 800
Galaxy Tab 3                    10"     1280 x  800     mdpi    1       160     1280 x 800      8:5     1.6000                  1280 x 800
ASUS Transformer                10"     1280 x  800     mdpi    1       160     1280 x 800      8:5     1.6000                  1280 x 800
ASUS Transformer 2              10"     1920 x 1200     hdpi    1.5     240     1280 x 800      8:5     1.6000                  1280 x 800
Nexus 10                        10"     2560 x  1600    xhdpi   2       320     1280 x 800      8:5     1.6000                  1280 x 800
Galaxy Note 10.1                10"     2560 x  1600    xhdpi   2       320     1280 x 800      8:5     1.6000                  1280 x 800
---------------------------     -----   ------------    --------------- ------- -----------     ----------------    ---         ----------
Device                          Inches  ResolutionPX    Density         DPI     ResolutionDP    AspectRatios        SysNavYorN  ContentResolutionDP
---------------------------     -----   ------------    --------------- ------- -----------     ----------------    ---         ----------

C# DateTime to "YYYYMMDDHHMMSS" format

Specify formatted DateTime as Utc:

Step 1 - Initial date

var initialDtm = DateTime.Now;

Step 2 - Format date as willing ("yyyyMMddHHmmss")

var formattedDtm = DateTime.ParseExact(initialDtm.ToString("yyyyMMddHHmmss"), "yyyyMMddHHmmss", CultureInfo.InvariantCulture);    

Step 3 - Specify kind of date (Utc)

var specifiedDtm = DateTime.SpecifyKind( formattedDtm, DateTimeKind.Utc);

What's the difference between .NET Core, .NET Framework, and Xamarin?

Xamarin is used for phone applications (both IOS/Android). The .NET Core is used for designing Web applications that can work on both Apache and IIS.

That is the difference in two sentences.

Explicit Return Type of Lambda

You can have more than one statement when still return:

[]() -> your_type {return (
        your_statement,
        even_more_statement = just_add_comma,
        return_value);}

http://www.cplusplus.com/doc/tutorial/operators/#comma

CSS fill remaining width

I know its quite late to answer this, but I guess it will help anyone ahead.

Well using CSS3 FlexBox. It can be acheived. Make you header as display:flex and divide its entire width into 3 parts. In the first part I have placed the logo, the searchbar in second part and buttons container in last part. apply justify-content: between to the header container and flex-grow:1 to the searchbar. That's it. The sample code is below.

_x000D_
_x000D_
#header {_x000D_
  background-color: #323C3E;_x000D_
  justify-content: space-between;_x000D_
  display: flex;_x000D_
}_x000D_
_x000D_
#searchBar, img{_x000D_
  align-self: center;_x000D_
}_x000D_
_x000D_
#searchBar{_x000D_
  flex-grow:1;_x000D_
  background-color: orange;_x000D_
  padding: 10px;_x000D_
}_x000D_
_x000D_
#searchBar input {_x000D_
  width: 100%;_x000D_
}_x000D_
_x000D_
.button {_x000D_
  padding: 22px;_x000D_
}_x000D_
_x000D_
.buttonsHolder{_x000D_
  display:flex;_x000D_
}
_x000D_
<div id="header" class="d-flex justify-content-between">_x000D_
    <img src="img/logo.png" />_x000D_
    <div id="searchBar">_x000D_
      <input type="text" />_x000D_
    </div>_x000D_
    <div class="buttonsHolder">_x000D_
      <div class="button orange inline" id="myAccount">_x000D_
        My Account_x000D_
      </div>_x000D_
      <div class="button red inline" id="basket">_x000D_
        Basket (2)_x000D_
      </div>_x000D_
    </div>_x000D_
</div>
_x000D_
_x000D_
_x000D_

invalid operands of types int and double to binary 'operator%'

Because % is only defined for integer types. That's the modulus operator.

5.6.2 of the standard:

The operands of * and / shall have arithmetic or enumeration type; the operands of % shall have integral or enumeration type. [...]

As Oli pointed out, you can use fmod(). Don't forget to include math.h.

Flask - Calling python function on button OnClick event

Easiest solution

<button type="button" onclick="window.location.href='{{ url_for( 'move_forward') }}';">Forward</button>

Inherit CSS class

Something like this:

.base {
    width:100px;
}

div.child {
    background-color:red;
    color:blue;
}

.child {
    background-color:yellow;
}

<div class="base child">
    hello world
</div>

The background here will be red, as the css selector is more specific, as we've said it must belong to a div element too!

see it in action here: jsFiddle

How can I tail a log file in Python?

Non Blocking

If you are on linux (as windows does not support calling select on files) you can use the subprocess module along with the select module.

import time
import subprocess
import select

f = subprocess.Popen(['tail','-F',filename],\
        stdout=subprocess.PIPE,stderr=subprocess.PIPE)
p = select.poll()
p.register(f.stdout)

while True:
    if p.poll(1):
        print f.stdout.readline()
    time.sleep(1)

This polls the output pipe for new data and prints it when it is available. Normally the time.sleep(1) and print f.stdout.readline() would be replaced with useful code.

Blocking

You can use the subprocess module without the extra select module calls.

import subprocess
f = subprocess.Popen(['tail','-F',filename],\
        stdout=subprocess.PIPE,stderr=subprocess.PIPE)
while True:
    line = f.stdout.readline()
    print line

This will also print new lines as they are added, but it will block until the tail program is closed, probably with f.kill().

How to connect from windows command prompt to mysql command line

If you're not on exact root of C:/ drive then first of all use cd../.. and then use query mysql -u username -p passsword

using the above lines you can access to mysql database.

Maven skip tests

To skip the test case during maven clean install i used -DskipTests paramater in following command

mvn clean install -DskipTests

into terminal window

Using Image control in WPF to display System.Drawing.Bitmap

It's easy for disk file, but harder for Bitmap in memory.

System.Drawing.Bitmap bmp;
Image image;
...
MemoryStream ms = new MemoryStream();
bmp.Save(ms, System.Drawing.Imaging.ImageFormat.Png);
ms.Position = 0;
BitmapImage bi = new BitmapImage();
bi.BeginInit();
bi.StreamSource = ms;
bi.EndInit();

image.Source = bi;

Stealed here

Permanently Set Postgresql Schema Path

(And if you have no admin access to the server)

ALTER ROLE <your_login_role> SET search_path TO a,b,c;

Two important things to know about:

  1. When a schema name is not simple, it needs to be wrapped in double quotes.
  2. The order in which you set default schemas a, b, c matters, as it is also the order in which the schemas will be looked up for tables. So if you have the same table name in more than one schema among the defaults, there will be no ambiguity, the server will always use the table from the first schema you specified for your search_path.

How to escape regular expression special characters using javascript?

With \ you escape special characters

Escapes special characters to literal and literal characters to special.

E.g: /\(s\)/ matches '(s)' while /(\s)/ matches any whitespace and captures the match.

Source: http://www.javascriptkit.com/javatutors/redev2.shtml

Create html documentation for C# code

This page might interest you: http://msdn.microsoft.com/en-us/magazine/dd722812.aspx

You can generate the XML documentation file using either the command-line compiler or through the Visual Studio interface. If you are compiling with the command-line compiler, use options /doc or /doc+. That will generate an XML file by the same name and in the same path as the assembly. To specify a different file name, use /doc:file.

If you are using the Visual Studio interface, there's a setting that controls whether the XML documentation file is generated. To set it, double-click My Project in Solution Explorer to open the Project Designer. Navigate to the Compile tab. Find "Generate XML documentation file" at the bottom of the window, and make sure it is checked. By default this setting is on. It generates an XML file using the same name and path as the assembly.

JavaScript by reference vs. by value

  1. Primitive type variable like string,number are always pass as pass by value.
  2. Array and Object is passed as pass by reference or pass by value based on these two condition.

    • if you are changing value of that Object or array with new Object or Array then it is pass by Value.

      object1 = {item: "car"}; array1=[1,2,3];

    here you are assigning new object or array to old one.you are not changing the value of property of old object.so it is pass by value.

    • if you are changing a property value of an object or array then it is pass by Reference.

      object1.item= "car"; array1[0]=9;

    here you are changing a property value of old object.you are not assigning new object or array to old one.so it is pass by reference.

Code

    function passVar(object1, object2, number1) {

        object1.key1= "laptop";
        object2 = {
            key2: "computer"
        };
        number1 = number1 + 1;
    }

    var object1 = {
        key1: "car"
    };
    var object2 = {
        key2: "bike"
    };
    var number1 = 10;

    passVar(object1, object2, number1);
    console.log(object1.key1);
    console.log(object2.key2);
    console.log(number1);

Output: -
    laptop
    bike
    10

Hibernate: How to set NULL query-parameter value with HQL?

I did not try this, but what happens when you use :status twice to check for NULL?

Query query = getSession().createQuery(
     "from CountryDTO c where ( c.status = :status OR ( c.status IS NULL AND :status IS NULL ) ) and c.type =:type"
)
.setParameter("status", status, Hibernate.STRING)
.setParameter("type", type, Hibernate.STRING);

Bootstrap 3 jquery event for active tab change

I use another approach.

Just try to find all a where id starts from some substring.

JS

$('a[id^=v-photos-tab]').click(function () {
     alert("Handler for .click() called.");
});

HTML

<a class="nav-item nav-link active show"  id="v-photos-tab-3a623245-7dc7-4a22-90d0-62705ad0c62b" data-toggle="pill" href="#v-photos-3a623245-7dc7-4a22-90d0-62705ad0c62b" role="tab" aria-controls="v-requestbase-photos" aria-selected="true"><span>Cool photos</span></a>

How can I fix MySQL error #1064?

TL;DR

Error #1064 means that MySQL can't understand your command. To fix it:

  • Read the error message. It tells you exactly where in your command MySQL got confused.

  • Examine your command. If you use a programming language to create your command, use echo, console.log(), or its equivalent to show the entire command so you can see it.

  • Check the manual. By comparing against what MySQL expected at that point, the problem is often obvious.

  • Check for reserved words. If the error occurred on an object identifier, check that it isn't a reserved word (and, if it is, ensure that it's properly quoted).

  1. Aaaagh!! What does #1064 mean?

    Error messages may look like gobbledygook, but they're (often) incredibly informative and provide sufficient detail to pinpoint what went wrong. By understanding exactly what MySQL is telling you, you can arm yourself to fix any problem of this sort in the future.

    As in many programs, MySQL errors are coded according to the type of problem that occurred. Error #1064 is a syntax error.

    • What is this "syntax" of which you speak? Is it witchcraft?

      Whilst "syntax" is a word that many programmers only encounter in the context of computers, it is in fact borrowed from wider linguistics. It refers to sentence structure: i.e. the rules of grammar; or, in other words, the rules that define what constitutes a valid sentence within the language.

      For example, the following English sentence contains a syntax error (because the indefinite article "a" must always precede a noun):

      This sentence contains syntax error a.

    • What does that have to do with MySQL?

      Whenever one issues a command to a computer, one of the very first things that it must do is "parse" that command in order to make sense of it. A "syntax error" means that the parser is unable to understand what is being asked because it does not constitute a valid command within the language: in other words, the command violates the grammar of the programming language.

      It's important to note that the computer must understand the command before it can do anything with it. Because there is a syntax error, MySQL has no idea what one is after and therefore gives up before it even looks at the database and therefore the schema or table contents are not relevant.

  2. How do I fix it?

    Obviously, one needs to determine how it is that the command violates MySQL's grammar. This may sound pretty impenetrable, but MySQL is trying really hard to help us here. All we need to do is…

    • Read the message!

      MySQL not only tells us exactly where the parser encountered the syntax error, but also makes a suggestion for fixing it. For example, consider the following SQL command:

      UPDATE my_table WHERE id=101 SET name='foo'
      

      That command yields the following error message:

      ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'WHERE id=101 SET name='foo'' at line 1

      MySQL is telling us that everything seemed fine up to the word WHERE, but then a problem was encountered. In other words, it wasn't expecting to encounter WHERE at that point.

      Messages that say ...near '' at line... simply mean that the end of command was encountered unexpectedly: that is, something else should appear before the command ends.

    • Examine the actual text of your command!

      Programmers often create SQL commands using a programming language. For example a php program might have a (wrong) line like this:

      $result = $mysqli->query("UPDATE " . $tablename ."SET name='foo' WHERE id=101");
      

      If you write this this in two lines

      $query = "UPDATE " . $tablename ."SET name='foo' WHERE id=101"
      $result = $mysqli->query($query);
      

      then you can add echo $query; or var_dump($query) to see that the query actually says

      UPDATE userSET name='foo' WHERE id=101
      

      Often you'll see your error immediately and be able to fix it.

    • Obey orders!

      MySQL is also recommending that we "check the manual that corresponds to our MySQL version for the right syntax to use". Let's do that.

      I'm using MySQL v5.6, so I'll turn to that version's manual entry for an UPDATE command. The very first thing on the page is the command's grammar (this is true for every command):

      UPDATE [LOW_PRIORITY] [IGNORE] table_reference
          SET col_name1={expr1|DEFAULT} [, col_name2={expr2|DEFAULT}] ...
          [WHERE where_condition]
          [ORDER BY ...]
          [LIMIT row_count]
      

      The manual explains how to interpret this syntax under Typographical and Syntax Conventions, but for our purposes it's enough to recognise that: clauses contained within square brackets [ and ] are optional; vertical bars | indicate alternatives; and ellipses ... denote either an omission for brevity, or that the preceding clause may be repeated.

      We already know that the parser believed everything in our command was okay prior to the WHERE keyword, or in other words up to and including the table reference. Looking at the grammar, we see that table_reference must be followed by the SET keyword: whereas in our command it was actually followed by the WHERE keyword. This explains why the parser reports that a problem was encountered at that point.

    A note of reservation

    Of course, this was a simple example. However, by following the two steps outlined above (i.e. observing exactly where in the command the parser found the grammar to be violated and comparing against the manual's description of what was expected at that point), virtually every syntax error can be readily identified.

    I say "virtually all", because there's a small class of problems that aren't quite so easy to spot—and that is where the parser believes that the language element encountered means one thing whereas you intend it to mean another. Take the following example:

    UPDATE my_table SET where='foo'
    

    Again, the parser does not expect to encounter WHERE at this point and so will raise a similar syntax error—but you hadn't intended for that where to be an SQL keyword: you had intended for it to identify a column for updating! However, as documented under Schema Object Names:

    If an identifier contains special characters or is a reserved word, you must quote it whenever you refer to it. (Exception: A reserved word that follows a period in a qualified name must be an identifier, so it need not be quoted.) Reserved words are listed at Section 9.3, “Keywords and Reserved Words”.

    [ deletia ]

    The identifier quote character is the backtick (“`”):

    mysql> SELECT * FROM `select` WHERE `select`.id > 100;

    If the ANSI_QUOTES SQL mode is enabled, it is also permissible to quote identifiers within double quotation marks:

    mysql> CREATE TABLE "test" (col INT);
    ERROR 1064: You have an error in your SQL syntax...
    mysql> SET sql_mode='ANSI_QUOTES';
    mysql> CREATE TABLE "test" (col INT);
    Query OK, 0 rows affected (0.00 sec)

SQL Error: ORA-00942 table or view does not exist

Here is an answer: http://www.dba-oracle.com/concepts/synonyms.htm

An Oracle synonym basically allows you to create a pointer to an object that exists somewhere else. You need Oracle synonyms because when you are logged into Oracle, it looks for all objects you are querying in your schema (account). If they are not there, it will give you an error telling you that they do not exist.

Delete all rows in table

Truncate table is faster than delete * from XXX. Delete is slow because it works one row at a time. There are a few situations where truncate doesn't work, which you can read about on MSDN.

Make iframe automatically adjust height according to the contents without using scrollbar?

I've had problems in the past calling iframe.onload for dynamically created iframes, so I went with this approach for setting the iframe size:

iFrame View

var height = $("body").outerHeight();
parent.SetIFrameHeight(height);

Main View

SetIFrameHeight = function(height) {
    $("#iFrameWrapper").height(height);
}

(this is only going to work if both views are in the same domain)

Get clicked item and its position in RecyclerView

Everytime I use another approach. People seem to store or get position on a view, rather than storing a reference to an object that is displayed by ViewHolder.

I use this approach instead, and just store it in ViewHolder when onBindViewHolder() is called, and set reference to null in onViewRecycled().

Every time ViewHolder becomes invisible, it's recycled. So this doesn't affect in large memory consumption.

@Override
public void onBindViewHolder(final ItemViewHolder holder, int position) {
    ...
    holder.displayedItem = adapterItemsList.get(i);
    ...
}

@Override
public void onViewRecycled(ItemViewHolder holder) {
    ...
    holder.displayedItem = null;
    ...
}

class ItemViewHolder extends RecyclerView.ViewHolder {
    ...
    MySuperItemObject displayedItem = null;
    ...
}

How do I URL encode a string

In Swift 3, please try out below:

let stringURL = "YOUR URL TO BE ENCODE";
let encodedURLString = stringURL.addingPercentEncoding(withAllowedCharacters: .urlHostAllowed)
print(encodedURLString)

Since, stringByAddingPercentEscapesUsingEncoding encodes non URL characters but leaves the reserved characters (like !*'();:@&=+$,/?%#[]), You can encode the url like the following code:

let stringURL = "YOUR URL TO BE ENCODE";
let characterSetTobeAllowed = (CharacterSet(charactersIn: "!*'();:@&=+$,/?%#[] ").inverted)
if let encodedURLString = stringURL.addingPercentEncoding(withAllowedCharacters: characterSetTobeAllowed) {
    print(encodedURLString)
}

Querying Windows Active Directory server using ldapsearch from command line

You could query an LDAP server from the command line with ldap-utils: ldapsearch, ldapadd, ldapmodify

How exactly does __attribute__((constructor)) work?

.init/.fini isn't deprecated. It's still part of the the ELF standard and I'd dare say it will be forever. Code in .init/.fini is run by the loader/runtime-linker when code is loaded/unloaded. I.e. on each ELF load (for example a shared library) code in .init will be run. It's still possible to use that mechanism to achieve about the same thing as with __attribute__((constructor))/((destructor)). It's old-school but it has some benefits.

.ctors/.dtors mechanism for example require support by system-rtl/loader/linker-script. This is far from certain to be available on all systems, for example deeply embedded systems where code executes on bare metal. I.e. even if __attribute__((constructor))/((destructor)) is supported by GCC, it's not certain it will run as it's up to the linker to organize it and to the loader (or in some cases, boot-code) to run it. To use .init/.fini instead, the easiest way is to use linker flags: -init & -fini (i.e. from GCC command line, syntax would be -Wl -init my_init -fini my_fini).

On system supporting both methods, one possible benefit is that code in .init is run before .ctors and code in .fini after .dtors. If order is relevant that's at least one crude but easy way to distinguish between init/exit functions.

A major drawback is that you can't easily have more than one _init and one _fini function per each loadable module and would probably have to fragment code in more .so than motivated. Another is that when using the linker method described above, one replaces the original _init and _fini default functions (provided by crti.o). This is where all sorts of initialization usually occur (on Linux this is where global variable assignment is initialized). A way around that is described here

Notice in the link above that a cascading to the original _init() is not needed as it's still in place. The call in the inline assembly however is x86-mnemonic and calling a function from assembly would look completely different for many other architectures (like ARM for example). I.e. code is not transparent.

.init/.fini and .ctors/.detors mechanisms are similar, but not quite. Code in .init/.fini runs "as is". I.e. you can have several functions in .init/.fini, but it is AFAIK syntactically difficult to put them there fully transparently in pure C without breaking up code in many small .so files.

.ctors/.dtors are differently organized than .init/.fini. .ctors/.dtors sections are both just tables with pointers to functions, and the "caller" is a system-provided loop that calls each function indirectly. I.e. the loop-caller can be architecture specific, but as it's part of the system (if it exists at all i.e.) it doesn't matter.

The following snippet adds new function pointers to the .ctors function array, principally the same way as __attribute__((constructor)) does (method can coexist with __attribute__((constructor))).

#define SECTION( S ) __attribute__ ((section ( S )))
void test(void) {
   printf("Hello\n");
}
void (*funcptr)(void) SECTION(".ctors") =test;
void (*funcptr2)(void) SECTION(".ctors") =test;
void (*funcptr3)(void) SECTION(".dtors") =test;

One can also add the function pointers to a completely different self-invented section. A modified linker script and an additional function mimicking the loader .ctors/.dtors loop is needed in such case. But with it one can achieve better control over execution order, add in-argument and return code handling e.t.a. (In a C++ project for example, it would be useful if in need of something running before or after global constructors).

I'd prefer __attribute__((constructor))/((destructor)) where possible, it's a simple and elegant solution even it feels like cheating. For bare-metal coders like myself, this is just not always an option.

Some good reference in the book Linkers & loaders.

What are file descriptors, explained in simple terms?

Hear it from the Horse's Mouth : APUE (Richard Stevens).
To the kernel, all open files are referred to by File Descriptors. A file descriptor is a non-negative number.

When we open an existing file or create a new file, the kernel returns a file descriptor to the process. The kernel maintains a table of all open file descriptors, which are in use. The allotment of file descriptors is generally sequential and they are allotted to the file as the next free file descriptor from the pool of free file descriptors. When we closes the file, the file descriptor gets freed and is available for further allotment.
See this image for more details :

Two Process

When we want to read or write a file, we identify the file with the file descriptor that was returned by open() or create() function call, and use it as an argument to either read() or write().
It is by convention that, UNIX System shells associates the file descriptor 0 with Standard Input of a process, file descriptor 1 with Standard Output, and file descriptor 2 with Standard Error.
File descriptor ranges from 0 to OPEN_MAX. File descriptor max value can be obtained with ulimit -n. For more information, go through 3rd chapter of APUE Book.

Convert generic List/Enumerable to DataTable?

I also had to come up with an alternate solution, as none of the options listed here worked in my case. I was using an IEnumerable which returned an IEnumerable and the properties couldn't be enumerated. This did the trick:

// remove "this" if not on C# 3.0 / .NET 3.5
public static DataTable ConvertToDataTable<T>(this IEnumerable<T> data)
{
    List<IDataRecord> list = data.Cast<IDataRecord>().ToList();

    PropertyDescriptorCollection props = null;
    DataTable table = new DataTable();
    if (list != null && list.Count > 0)
    {
        props = TypeDescriptor.GetProperties(list[0]);
        for (int i = 0; i < props.Count; i++)
        {
            PropertyDescriptor prop = props[i];
            table.Columns.Add(prop.Name, Nullable.GetUnderlyingType(prop.PropertyType) ?? prop.PropertyType);
        }
    }
    if (props != null)
    {
        object[] values = new object[props.Count];
        foreach (T item in data)
        {
            for (int i = 0; i < values.Length; i++)
            {
                values[i] = props[i].GetValue(item) ?? DBNull.Value;
            }
            table.Rows.Add(values);
        }
    }
    return table;
}

Control flow in T-SQL SP using IF..ELSE IF - are there other ways?

CASE expression
      WHEN value1 THEN result1
      WHEN value2 THEN result2
      ...
      WHEN valueN THEN resultN

      [
        ELSE elseResult
      ]
END

http://www.4guysfromrolla.com/webtech/102704-1.shtml For more information.

pip install failing with: OSError: [Errno 13] Permission denied on directory

It is due permission problem,

sudo chown -R $USER /path to your python installed directory

default it would be /usr/local/lib/python2.7/

or try,

pip install --user -r package_name

and then say, pip install -r requirements.txt this will install inside your env

dont say, sudo pip install -r requirements.txt this is will install into arbitrary python path.

Is there a way to create interfaces in ES6 / Node 4?

This is my solution for the problem. You can 'implement' multiple interfaces by overriding one Interface with another.

class MyInterface {
    // Declare your JS doc in the Interface to make it acceable while writing the Class and for later inheritance
    /**
     * Gives the sum of the given Numbers
     * @param {Number} a The first Number
     * @param {Number} b The second Number
     * @return {Number} The sum of the Numbers
     */
    sum(a, b) { this._WARNING('sum(a, b)'); }


    // delcare a warning generator to notice if a method of the interface is not overridden
    // Needs the function name of the Interface method or any String that gives you a hint ;)
    _WARNING(fName='unknown method') {
        console.warn('WARNING! Function "'+fName+'" is not overridden in '+this.constructor.name);
    }
}

class MultipleInterfaces extends MyInterface {
    // this is used for "implement" multiple Interfaces at once
    /**
     * Gives the square of the given Number
     * @param {Number} a The Number
     * @return {Number} The square of the Numbers
     */
    square(a) { this._WARNING('square(a)'); }
}

class MyCorrectUsedClass extends MyInterface {
    // You can easy use the JS doc declared in the interface
    /** @inheritdoc */
    sum(a, b) {
        return a+b;
    }
}
class MyIncorrectUsedClass extends MyInterface {
    // not overriding the method sum(a, b)
}

class MyMultipleInterfacesClass extends MultipleInterfaces {
    // nothing overriden to show, that it still works
}


let working = new MyCorrectUsedClass();

let notWorking = new MyIncorrectUsedClass();

let multipleInterfacesInstance = new MyMultipleInterfacesClass();

// TEST IT

console.log('working.sum(1, 2) =', working.sum(1, 2));
// output: 'working.sum(1, 2) = 3'

console.log('notWorking.sum(1, 2) =', notWorking.sum(1, 2));
// output: 'notWorking.sum(1, 2) = undefined'
// but also sends a warn to the console with 'WARNING! Function "sum(a, b)" is not overridden in MyIncorrectUsedClass'

console.log('multipleInterfacesInstance.sum(1, 2) =', multipleInterfacesInstance.sum(1, 2));
// output: 'multipleInterfacesInstance.sum(1, 2) = undefined'
// console warn: 'WARNING! Function "sum(a, b)" is not overridden in MyMultipleInterfacesClass'

console.log('multipleInterfacesInstance.square(2) =', multipleInterfacesInstance.square(2));
// output: 'multipleInterfacesInstance.square(2) = undefined'
// console warn: 'WARNING! Function "square(a)" is not overridden in MyMultipleInterfacesClass'

EDIT:

I improved the code so you now can simply use implement(baseClass, interface1, interface2, ...) in the extend.

/**
* Implements any number of interfaces to a given class.
* @param cls The class you want to use
* @param interfaces Any amount of interfaces separated by comma
* @return The class cls exteded with all methods of all implemented interfaces
*/
function implement(cls, ...interfaces) {
    let clsPrototype = Object.getPrototypeOf(cls).prototype;
    for (let i = 0; i < interfaces.length; i++) {
        let proto = interfaces[i].prototype;
        for (let methodName of Object.getOwnPropertyNames(proto)) {
            if (methodName!== 'constructor')
                if (typeof proto[methodName] === 'function')
                    if (!clsPrototype[methodName]) {
                        console.warn('WARNING! "'+methodName+'" of Interface "'+interfaces[i].name+'" is not declared in class "'+cls.name+'"');
                        clsPrototype[methodName] = proto[methodName];
                    }
        }
    }
    return cls;
}

// Basic Interface to warn, whenever an not overridden method is used
class MyBaseInterface {
    // declare a warning generator to notice if a method of the interface is not overridden
    // Needs the function name of the Interface method or any String that gives you a hint ;)
    _WARNING(fName='unknown method') {
        console.warn('WARNING! Function "'+fName+'" is not overridden in '+this.constructor.name);
    }
}


// create a custom class
/* This is the simplest example but you could also use
*
*   class MyCustomClass1 extends implement(MyBaseInterface) {
*       foo() {return 66;}
*   }
*
*/
class MyCustomClass1 extends MyBaseInterface {
    foo() {return 66;}
}

// create a custom interface
class MyCustomInterface1 {
     // Declare your JS doc in the Interface to make it acceable while writing the Class and for later inheritance

    /**
     * Gives the sum of the given Numbers
     * @param {Number} a The first Number
     * @param {Number} b The second Number
     * @return {Number} The sum of the Numbers
     */
    sum(a, b) { this._WARNING('sum(a, b)'); }
}

// and another custom interface
class MyCustomInterface2 {
    /**
     * Gives the square of the given Number
     * @param {Number} a The Number
     * @return {Number} The square of the Numbers
     */
    square(a) { this._WARNING('square(a)'); }
}

// Extend your custom class even more and implement the custom interfaces
class AllInterfacesImplemented extends implement(MyCustomClass1, MyCustomInterface1, MyCustomInterface2) {
    /**
    * @inheritdoc
    */
    sum(a, b) { return a+b; }

    /**
    * Multiplies two Numbers
    * @param {Number} a The first Number
    * @param {Number} b The second Number
    * @return {Number}
    */
    multiply(a, b) {return a*b;}
}


// TEST IT

let x = new AllInterfacesImplemented();

console.log("x.foo() =", x.foo());
//output: 'x.foo() = 66'

console.log("x.square(2) =", x.square(2));
// output: 'x.square(2) = undefined
// console warn: 'WARNING! Function "square(a)" is not overridden in AllInterfacesImplemented'

console.log("x.sum(1, 2) =", x.sum(1, 2));
// output: 'x.sum(1, 2) = 3'

console.log("x.multiply(4, 5) =", x.multiply(4, 5));
// output: 'x.multiply(4, 5) = 20'

Delete with Join in MySQL

MySQL DELETE records with JOIN

You generally use INNER JOIN in the SELECT statement to select records from a table that have corresponding records in other tables. We can also use the INNER JOIN clause with the DELETE statement to delete records from a table and also the corresponding records in other tables e.g., to delete records from both T1 and T2 tables that meet a particular condition, you use the following statement:

DELETE T1, T2
FROM T1
INNER JOIN T2 ON T1.key = T2.key
WHERE condition

Notice that you put table names T1 and T2 between DELETE and FROM. If you omit the T1 table, the DELETE statement only deletes records in the T2 table, and if you omit the T2 table, only records in the T1 table are deleted.

The join condition T1.key = T2.key specifies the corresponding records in the T2 table that need be deleted.

The condition in the WHERE clause specifies which records in the T1 and T2 that need to be deleted.

ORA-00054: resource busy and acquire with NOWAIT specified or timeout expired

Solution given by Shashi's link is the best... no needs to contact dba or someone else

make a backup

create table xxxx_backup as select * from xxxx;

delete all rows

delete from xxxx;
commit;

insert your backup.

insert into xxxx (select * from xxxx_backup);
commit;

Runtime vs. Compile time

I have always thought of it relative to program processing overhead and how it affects preformance as previously stated. A simple example would be, either defining the absolute memory required for my object in code or not.

A defined boolean takes x memory this is then in the compiled program and cannot be changed. When the program runs it knows exactly how much memory to allocate for x.

On the other hand if I just define a generic object type (i.e. kind of a undefined place holder or maybe a pointer to some giant blob) the actual memory required for my object is not known until the program is run and I assign something to it, thus it then must be evaluated and memory allocation, etc. will be then handled dynamically at run time (more run time overhead).

How it is dynamically handled would then depend on the language, the compiler, the OS, your code, etc.

On that note however it would really depends on the context in which you are using run time vs compile time.

How to perform a fade animation on Activity transition?

you can also use this code in your style.xml file so you don't need to write anything else in your activity.java

<!-- Base application theme. -->
<style name="AppTheme" parent="Theme.AppCompat.Light.NoActionBar">
    <!-- Customize your theme here. -->
    <item name="colorPrimary">@color/colorPrimary</item>
    <item name="colorPrimaryDark">@color/colorPrimaryDark</item>
    <item name="colorAccent">@color/colorAccent</item>
    <item name="android:windowAnimationStyle">@style/AppTheme.WindowTransition</item>
</style>

<!-- Setting window animation -->
<style name="AppTheme.WindowTransition">
    <item name="android:windowEnterAnimation">@android:anim/fade_in</item>
    <item name="android:windowExitAnimation">@android:anim/fade_out</item>
</style>

How to maintain a Unique List in Java?

You can use a Set implementation:

Some info from the JAVADoc:

A collection that contains no duplicate elements. More formally, sets contain no pair of elements e1 and e2 such that e1.equals(e2), and at most one null element. As implied by its name, this interface models the mathematical set abstraction.

Note: Great care must be exercised if mutable objects are used as set elements. The behavior of a set is not specified if the value of an object is changed in a manner that affects equals comparisons while the object is an element in the set. A special case of this prohibition is that it is not permissible for a set to contain itself as an element.`

These are the implementations:

  • HashSet

    This class offers constant time performance for the basic operations (add, remove, contains and size), assuming the hash function disperses the elements properly among the buckets. Iterating over this set requires time proportional to the sum of the HashSet instance's size (the number of elements) plus the "capacity" of the backing HashMap instance (the number of buckets). Thus, it's very important not to set the initial capacity too high (or the load factor too low) if iteration performance is important.

    When iterating a HashSet the order of the yielded elements is undefined.

  • LinkedHashSet

    Hash table and linked list implementation of the Set interface, with predictable iteration order. This implementation differs from HashSet in that it maintains a doubly-linked list running through all of its entries. This linked list defines the iteration ordering, which is the order in which elements were inserted into the set (insertion-order). Note that insertion order is not affected if an element is re-inserted into the set. (An element e is reinserted into a set s if s.add(e) is invoked when s.contains(e) would return true immediately prior to the invocation.)

    So, the output of the code above...

     Set<Integer> linkedHashSet = new LinkedHashSet<>();
     linkedHashSet.add(3);
     linkedHashSet.add(1);
     linkedHashSet.add(2);
    
     for (int i : linkedHashSet) {
         System.out.println(i);
     }
    

    ...will necessarily be

    3
    1
    2
    
  • TreeSet

    This implementation provides guaranteed log(n) time cost for the basic operations (add, remove and contains). By default he elements returned on iteration are sorted by their "natural ordering", so the code above...

     Set<Integer> treeSet = new TreeSet<>();
     treeSet.add(3);
     treeSet.add(1);
     treeSet.add(2);
    
     for (int i : treeSet) {
         System.out.println(i);
     }
    

    ...will output this:

    1
    2
    3
    

    (You can also pass a Comparator instance to a TreeSet constructor, making it sort the elements in a different order.)

    Note that the ordering maintained by a set (whether or not an explicit comparator is provided) must be consistent with equals if it is to correctly implement the Set interface. (See Comparable or Comparator for a precise definition of consistent with equals.) This is so because the Set interface is defined in terms of the equals operation, but a TreeSet instance performs all element comparisons using its compareTo (or compare) method, so two elements that are deemed equal by this method are, from the standpoint of the set, equal. The behavior of a set is well-defined even if its ordering is inconsistent with equals; it just fails to obey the general contract of the Set interface.

How can we print line numbers to the log in java

My way it works for me

String str = "select os.name from os where os.idos="+nameid;  try {
        PreparedStatement stmt = conn.prepareStatement(str);
        ResultSet rs = stmt.executeQuery();
        if (rs.next()) {
            a = rs.getString("os.n1ame");//<<<----Here is the ERROR          
        }
        stmt.close();
  } catch (SQLException e) {
        System.out.println("error line : " + e.getStackTrace()[2].getLineNumber());            
        return a;
  }

Running JAR file on Windows

If you have a jar file called Example.jar, follow these rules:

  1. Open a notepad.exe
  2. Write : java -jar Example.jar
  3. Save it with the extension .bat
  4. Copy it to the directory which has the .jar file
  5. Double click it to run your .jar file

The operation couldn’t be completed. (com.facebook.sdk error 2.) ios6

I had a similar issue. the error comes up when the i switched the fb user from setting. Facebook authorization fails on iOS6 when switching FB account on device This solved my problem

In Python, how to check if a string only contains certain characters?

Here's a simple, pure-Python implementation. It should be used when performance is not critical (included for future Googlers).

import string
allowed = set(string.ascii_lowercase + string.digits + '.')

def check(test_str):
    set(test_str) <= allowed

Regarding performance, iteration will probably be the fastest method. Regexes have to iterate through a state machine, and the set equality solution has to build a temporary set. However, the difference is unlikely to matter much. If performance of this function is very important, write it as a C extension module with a switch statement (which will be compiled to a jump table).

Here's a C implementation, which uses if statements due to space constraints. If you absolutely need the tiny bit of extra speed, write out the switch-case. In my tests, it performs very well (2 seconds vs 9 seconds in benchmarks against the regex).

#define PY_SSIZE_T_CLEAN
#include <Python.h>

static PyObject *check(PyObject *self, PyObject *args)
{
        const char *s;
        Py_ssize_t count, ii;
        char c;
        if (0 == PyArg_ParseTuple (args, "s#", &s, &count)) {
                return NULL;
        }
        for (ii = 0; ii < count; ii++) {
                c = s[ii];
                if ((c < '0' && c != '.') || c > 'z') {
                        Py_RETURN_FALSE;
                }
                if (c > '9' && c < 'a') {
                        Py_RETURN_FALSE;
                }
        }

        Py_RETURN_TRUE;
}

PyDoc_STRVAR (DOC, "Fast stringcheck");
static PyMethodDef PROCEDURES[] = {
        {"check", (PyCFunction) (check), METH_VARARGS, NULL},
        {NULL, NULL}
};
PyMODINIT_FUNC
initstringcheck (void) {
        Py_InitModule3 ("stringcheck", PROCEDURES, DOC);
}

Include it in your setup.py:

from distutils.core import setup, Extension
ext_modules = [
    Extension ('stringcheck', ['stringcheck.c']),
],

Use as:

>>> from stringcheck import check
>>> check("abc")
True
>>> check("ABC")
False

How to submit a form when the return key is pressed?

Here is how I do it with jQuery

j(".textBoxClass").keypress(function(e)
{
    // if the key pressed is the enter key
    if (e.which == 13)
    {
        // do work
    }
});

Other javascript wouldnt be too different. the catch is checking for keypress argument of "13", which is the enter key

How do I add a delay in a JavaScript loop?

You do it:

_x000D_
_x000D_
console.log('hi')_x000D_
let start = 1_x000D_
setTimeout(function(){_x000D_
  let interval = setInterval(function(){_x000D_
    if(start == 10) clearInterval(interval)_x000D_
    start++_x000D_
    console.log('hello')_x000D_
  }, 3000)_x000D_
}, 3000)
_x000D_
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
_x000D_
_x000D_
_x000D_