No, and is [not going to happen.][1]

Last comment from dev says: 
&gt;We&#39;re going to hold off on this feature for now. It&#39;s complexity is high and it&#39;s not common enough a workflow. One could also just comment out the lines and hit ctrl-s to get the same effect, pretty much. Status: WontFix –

The workaround is to comment out the line you want to skip and press &lt;kbd&gt;Ctrl&lt;/kbd&gt;+&lt;kbd&gt;S&lt;/kbd&gt;. 

  [1]: https://code.google.com/p/chromium/issues/detail?can=6&amp;q=skip%20line%20while%20debugging&amp;id=382904&amp;thanks=382904&amp;ts=1402405661#hc6


I know the importance of indexes and how order of joins can change performance. I&#39;ve done a bunch of reading related to multi-column indexes and haven&#39;t found the answer to my question.

I&#39;m curious if I do a multi-column index, if the order that they are specified matters at all. My guess is that it would not, and that the engine would treat them as a group, where ordering doesn&#39;t matter. But I wish to verify.

For example, from mysql&#39;s website (http://dev.mysql.com/doc/refman/5.0/en/multiple-column-indexes.html)

    CREATE TABLE test (
        id         INT NOT NULL,
        last_name  CHAR(30) NOT NULL,
        first_name CHAR(30) NOT NULL,
        PRIMARY KEY (id),
        INDEX name (last_name,first_name)
    );

Would there be any benifit in any cases where the following would be better, or is it equivalent?

    CREATE TABLE test (
        id         INT NOT NULL,
        last_name  CHAR(30) NOT NULL,
        first_name CHAR(30) NOT NULL,
        PRIMARY KEY (id),
        INDEX name (first_name,last_name)
    );

Specificially:

    INDEX name (last_name,first_name)

vs

    INDEX name (first_name,last_name)

Does Order of Fields of Multi-Column Index in MySQL Matter

Here are my codes, pretty standard but I am getting the error msg:

    library(caret)
    set.seed(32343)
    modelFit = train(type~.,data=training, method=&#39;glm&#39;)

error msg:

    Error in library(e1071) : there is no package called ‘e1071’

Any idea? Thanks!

Using Caret Package but Getting Error in library(e1071)

Is there a feature in Google Chrome developer tools that would allow skipping a line without it being executed while debugging, in a similar way that it can be done in Visual Studio?

One workaround I can think of is &#39;live editing&#39; the code by wrapping the line in

    if(false){ //line to be skipped }

But this is not the most convenient workaround that I would have to do after every refresh. **Is there a built-in or faster, better way of doing this?**


Skip line while debugging in Chrome developer tools

Is there a feature in Google Chrome developer tools that would allow skipping a line without it being executed while debugging, in a similar way that it can be done in Visual Studio?
One workaround I can think of is 'live editing' the code by wrapping the line in
<pre><code class="hljs language-scss">if(false){ //line to be skipped }
</code></pre>
But this is not the most convenient workaround that I would have to do after every refresh. Is there a built-in or faster, better way of doing this?

I was helping a colleague debug some code today and I noticed a strange behavior with `console.log()` in Google Chrome:

It appears that if you:

1. Create a nested array (e.g., [[345,&quot;test&quot;]])

2. Log the array to the console with `console.log()`.

3. Modify one of the inner array values, then `console.log()` will output the later value -- **not** the values of the array at the time the `console.log()` was executed.

**JavaScript**:

    var test = [[2345235345,&quot;test&quot;]]
    console.log(test);
    test[0][0] = 1111111;
    // outputs: [[1111111,&quot;test&quot;]]
    
    var testb = {};
    testb.test = &quot;test&quot;;
    console.log(testb);
    testb.test = &quot;sdfgsdfg&quot;;
    // outputs: {&quot;testb&quot;:&quot;test&quot;}

    
    var testc = [&quot;test&quot;,&quot;test2&quot;];
    console.log(testc);
    testc[0] = &quot;sdxfsdf&quot;;
    // outputs: [&quot;test&quot;,&quot;test2&quot;]

**[JSFiddle Example][1]**

This behavior does not happen in Firefox.

Also to note, if I stepped through his code line by line in the Chrome debugger, then `console.log()` would output the correct values.

Is there an explanation for this strange phenomenon or is it just a bug with Google Chrome? 

**EDIT:**

I&#39;ve narrowed down the steps to reproduce the inconsistent `console.log()` behavior: 

If you add this script to your page:

    var greetings=[&#39;hi&#39;,&#39;bye&#39;];
    console.log(greetings);
    setTimeout(function(){
        greetings.push(&#39;goodbye&#39;);
    },3000);

and open it in a new window with the Chrome **console window already open**, then the `console.log()` output will be different than if you load the page with the **console window closed**. [Here&#39;s a JSFiddle that demonstrates that](http://jsfiddle.net/markasoftware/kcGkZ/).

In the first case, with the console window already open, `console.log()` will output the current value of the array (i.e., two items). 

In the second case, with the console window initially closed and opened only *after* the page loads, `console.log()` will output the later values of the array (i.e., three items). 

Is this a bug in Google Chrome&#39;s `console.log()` functionality?

  [1]: http://jsfiddle.net/ju3ZV/2/
  [2]: https://vidd.me/dLH

Google Chrome console.log() inconsistency with objects and arrays

I am practicing JavaScript on Chrome&#39;s &#39;JavaScript Console&#39; ( version: 35.0) and I am unable to use the &#39;use strict&#39; clause as expected.

For the following code snippet :

    var obj={x:1,y:2}
    
    //Define new property with &#39;writable&#39; flag as false.
    Object.defineProperty(obj, &quot;z&quot;, {value:3, writable:false, enumerable:false, configurable:false})
    
    // Try to change the property &#39;z&#39;,
    &quot;use strict&quot;; obj[&quot;z&quot;]=4

&gt; Output: 4

As per my understanding, changing value of a &#39;non-writable&#39; property will silently fail in non-strict mode and throw &#39;TypeError&#39; in strict mode, But I don&#39;t see the exception.

    console.log(obj)

&gt; Object {x: 1, y: 2, z: 3}

Even though the property value is not changed but I am expecting a exception. 
Please correct if I am doing something wrong ?

How to use &#39;strict&#39; mode in Chrome &#39;JavaScript Console&#39;

I&#39;m trying to set cursor: pointer on a dom element, but the input isn&#39;t taking it (I am not seeing a pointer cursor when I hover over the checkbox). In chrome, I see that the &quot;user agent stylesheet&quot; is overriding my css. Wtf?

    &lt;!doctype html&gt;
    &lt;body&gt;
        &lt;div class=&#39;a&#39;&gt;
            &lt;input type=&#39;checkbox&#39;&gt;
        &lt;/div&gt;
    
        &lt;style&gt;
            .a {
                cursor: pointer;
            }
        &lt;/style&gt;
    &lt;/body&gt;

I have seen this question: https://stackoverflow.com/questions/11348727/why-does-user-agent-stylesheet-override-my-styles But my problem does not seem to be the doctype, which is [the recommended doctype][1]. 

Using `!important` isn&#39;t acceptable here, and neither is styling the input node directly - I shouldn&#39;t have to worry about weird browser useragent styles. What&#39;s going on?

To clarify, my question is about why the user agent stylesheet is overriding the css and how to make *that* stop. My question is *not* how I can hack around this behavior. If I&#39;m not mistaken, the correct behavior of css is that the cursor style should be inherited by child nodes.

Is this the expected behavior of css? 

  [1]: https://developer.mozilla.org/en-US/docs/Web/Guide/HTML/HTML5/Introduction_to_HTML5

How to stop user agent stylesheets from overriding my css

Ever since I upgraded to Postman 0.9.6 I can&#39;t replicate user sessions because chrome doesn&#39;t allow postman to get user cookies. However, they have decided to &quot;work around&quot; this issue by created another plugin called Postman Interceptor that routes your postman request and grabs the user cookies. They wrote a blog post about this wonderful tool here: http://blog.getpostman.com/index.php/2014/02/11/postman-v0-9-6-access-cookies-and-restricted-headers-plus-better-testing/

However, I can&#39;t seem to figure out how to get this thing to work. I have been trying for an hour now, and it still won&#39;t see my request as a logged in user

How to use Postman Interceptor

I&#39;m trying to access a script as JSON via AJAX, which works fine on Safari and other browsers but unfortunately will not execute in Chrome. It&#39;s coming with the following error:

&gt; Refused to execute script from &#39;*&#39; because its MIME type (&#39;application/json&#39;) is not executable, and strict MIME type checking is enabled.

Here&#39;s the request:

    $.ajax({
        url: &quot;http://some_url/test.json?callback=?&quot;,
        type: &quot;GET&quot;,
        dataType: &#39;json&#39;,
        cache: true,
        success: function (data, status, error) {
          console.log(&#39;success&#39;, data);
        },
        error: function (data, status, error) {
          console.log(&#39;error&#39;, data, status, error);
        }
    });

Does anyone have a workaround for this?

Chrome refuses to execute an AJAX script due to wrong MIME type

In debugging my code, I want to use a list comprehension. However, it seems I cannot evaluate a list comprehension from the debugger when I&#39;m inside a function.

I am using Python 3.4.

**Script contents**:

    $ cat test.py 
    #!/usr/bin/python
    
    def foo():
        x = [1, 2, 3, 3, 4]
    
        print(x)
    
    foo()

**Interactive debugging:**

    $ python3 -mpdb test.py                                                                                                                                           
    &gt; /tmp/test.py(3)&lt;module&gt;()
    -&gt; def foo():
    (Pdb) step
    &gt; /tmp/test.py(8)&lt;module&gt;()
    -&gt; foo()
    (Pdb) 
    --Call--
    &gt; /tmp/test.py(3)foo()
    -&gt; def foo():
    (Pdb) 
    &gt; /tmp/test.py(4)foo()
    -&gt; x = [1, 2, 3, 3, 4]
    (Pdb) 
    &gt; /tmp/test.py(6)foo()
    -&gt; print(x)
    (Pdb) p [x for _ in range(1)]
    *** NameError: name &#39;x&#39; is not defined
    (Pdb) p x
    [1, 2, 3, 3, 4]

Why is `x` unknown to the list comprehension?  How could I evaluate a list comprehension from the debugger, or achieve an equivalent behaviour?  Is this a bug, or is it some sort of fundamental limitation to the debugger?

List comprehension scope error from Python debugger

I can&#39;t attach Android Studio&#39;s debugger to my debuggable application process. Anyone else had this issue? Basically I can&#39;t get my app listed in `Choose Process` dialog. 

I&#39;m selecting `Attach debugger to Android process`:

![Attach debugger to Android process][1]

And then, here&#39;s how `Process selection` dialog from Android Studio looks like:

![No app is in the list to be debugged][2]

Any ideas why my app is not shown in the `Choose Process` list?

Although, `DDMS` sees my app in `Devices | logcat` list:

![`Devices | logcat` list][3]

`Android Monitor` also sees the app in `Devices` list:

![Android Monitor | Devices list][4]

I&#39;ve tried these actions:

* Restarting `MacBook` 
* Restarting devices: tried with `Samsung Galaxy Note II N7100` (4.3) and `Samsung Galaxy S4` (4.4.2)
* Reenabling `Settings-&gt;Developer Options` on the devices
* Reenabling `Settings-&gt;Developer Options-&gt;USB debugging` on the devices
* Restarting `adb` by running `adb kill-server` and `adb start-server`
* Reconnecting device from macbook and/or plugging to another USB port
* Launching Genymotion virtual device on macbook
* `restarting in TCP mode port: 5555` by running `adb tcpip 5555` and then connecting to it with `adb connect 192.168.1.87`
* `Waiting more`&amp;`Restart` when got this error saying `ADB not responding. You can wait more, or kill &quot;adb&quot; process manually and click &#39;Restart&#39;` `Errors in ADB:` `ddms: &#39;$ANDROID_HOME/platform-tools/adb,start-server&#39; failed -- run manually if necessary` [Error screenshot][5]

**Update:**

What I&#39;ve noticed is that device appears multiple times in the `Android DDMS`-&gt;`Devices | logcat` list. If I choose 1st device from the list, it shows, there&#39;s `No debuggable applications`, but I select last device (4th in the screenshot) I see my debuggable application. See screenshots: [1st][6] and [4th][7]. Although, even there&#39;s only 1 device in the list and showing debuggable device and application, process still does not appear in the `Choose Process` dialog.


  [1]: http://i.stack.imgur.com/dxirc.png
  [2]: http://i.stack.imgur.com/USVj7.png
  [3]: http://i.stack.imgur.com/EEx93.png
  [4]: http://i.stack.imgur.com/XPAdE.png
  [5]: http://i.stack.imgur.com/kWEdv.png
  [6]: http://i.stack.imgur.com/Syqo8.png
  [7]: http://i.stack.imgur.com/y5Etm.png

Can&#39;t attach Android Studio&#39;s debugger to Android process

I&#39;m currently building quite a complex system in Python, and when I&#39;m debugging I often put simple print statements in several scripts. To keep an overview I often also want to print out the file name and line number where the print statement is located. I can of course do that manually, or with something like this:

    from inspect import currentframe, getframeinfo

    print getframeinfo(currentframe()).filename + &#39;:&#39; + str(getframeinfo(currentframe()).lineno) + &#39; - &#39;, &#39;what I actually want to print out here&#39;

Which prints something like:
```
filenameX.py:273 - what I actually want to print out here
```

To make it more simple, I want to be able to do something like:

    print debuginfo(), &#39;what I actually want to print out here&#39;

So I put it into a function somewhere and tried doing:

    from debugutil import debuginfo
    print debuginfo(), &#39;what I actually want to print out here&#39;
    print debuginfo(), &#39;and something else here&#39;

Unfortunately, I get:

    debugutil.py:3 - what I actually want to print out here
    debugutil.py:3 - and something else here

It prints out the file name and line number on which I defined the function, instead of the line on which I call `debuginfo()`. This is obvious, because the code is located in the `debugutil.py` file. 

So my question is actually: **How can I get the filename and line number from which this debuginfo() function is called?**


Debugging: Get filename and line number from which a function is called?

In our project we are migrating to java 8 and we are testing the new features of it.

On my project I&#39;m using Guava predicates and functions to filter and transform some collections using `Collections2.transform` and `Collections2.filter`. 

On this migration I need to change for example guava code to java 8 changes. So, the changes I&#39;m doing are the kind of:

    List&lt;Integer&gt; naturals = Lists.newArrayList(1,2,3,4,5,6,7,8,9,10,11,12,13);
		
	Function &lt;Integer, Integer&gt; duplicate = new Function&lt;Integer, Integer&gt;(){
		@Override
		public Integer apply(Integer n)
		{
			return n * 2;
		}
	};
		
	Collection result = Collections2.transform(naturals, duplicate);

To...

    List&lt;Integer&gt; result2 = naturals.stream()
		.map(n -&gt; n * 2)
		.collect(Collectors.toList());

Using guava I was very confortable debugging the code since I could debug each transformation process but my concern is how to debug for example `.map(n -&gt; n*2)`.

Using the debugger I can see some code like:

    @Hidden
    @DontInline
    /** Interpretively invoke this form on the given arguments. */
    Object interpretWithArguments(Object... argumentValues) throws Throwable {
        if (TRACE_INTERPRETER)
            return interpretWithArgumentsTracing(argumentValues);
        checkInvocationCounter();
        assert(arityCheck(argumentValues));
        Object[] values = Arrays.copyOf(argumentValues, names.length);
        for (int i = argumentValues.length; i &lt; values.length; i++) {
            values[i] = interpretName(names[i], values);
        }
        return (result &lt; 0) ? null : values[result];
    }

But it isn&#39;t as straighforward as Guava to debug the code, actually I couldn&#39;t find the `n * 2` transformation.

Is there a way to see this transformation or a way to easy debug this code?

**EDIT: I&#39;ve added answer from different comments and posted answers**

Thanks to `Holger` comment that answered my question, the approach of having lambda block allowed me to see the transformation process and debug what happened inside lambda body:

    .map(
		n -&gt; {
			Integer nr = n * 2;
			return nr;
		}
	)

Thanks to `Stuart Marks` the approach of having method references also allowed me to debug the transformation process:

    static int timesTwo(int n) {
		Integer result = n * 2;
	    return result;
	}
    ...
    List&lt;Integer&gt; result2 = naturals.stream()
		.map(Java8Test::timesTwo)
		.collect(Collectors.toList());
    ...


Thanks to `Marlon Bernardes` answer I noticed that my Eclipse doesn&#39;t show what it should and the usage of peek() helped to display results. 

How to debug stream().map(...) with lambda expressions?

I have been adding logs to the console to check the status of different variables without using the Firefox debugger. 

However, in many places in which I add a `console.log` in my `main.js` file, I receive the following error instead of my lovely little handwritten messages to myself: 

&gt;Synchronous XMLHttpRequest on the main thread is deprecated because of its detrimental effects to the end user&#39;s experience. For more help http://xhr.spec.whatwg.org/

What alternatives to or wrappers for `console.log` can I add to my code use that will not cause this error? 

Am I &quot;doing it wrong&quot;? 

JavaScript console.log causes error: &quot;Synchronous XMLHttpRequest on the main thread is deprecated...&quot;

I&#39;m having an error running Chromecast sender in Chrome Incognito or if Chromecast extension is not installed:

    Failed to load resource: net::ERR_ADDRESS_UNREACHABLE chrome-extension://boadgeojelhgndaghljhdicfkmllpafd/cast_sender.js
    Failed to load resource: net::ERR_ADDRESS_UNREACHABLE chrome-extension://dliochdbjfkdbacpmhlcpmleaejidimm/cast_sender.js
    Failed to load resource: net::ERR_ADDRESS_UNREACHABLE chrome-extension://hfaagokkkhdbgiakmmlclaapfelnkoah/cast_sender.js
    Failed to load resource: net::ERR_ADDRESS_UNREACHABLE chrome-extension://fmfcbgogabcbclcofgocippekhfcmgfj/cast_sender.js
    Failed to load resource: net::ERR_ADDRESS_UNREACHABLE chrome-extension://enhhojjnijigcajfphajepfemndkmdlo/cast_sender.js
    No cast extension found

Google cast sender is trying to send AJAX requests for local &quot;cast_sender.js&quot;. Should this happen or is there a better way to check if Chromecast sender extension exists (not by requesting AJAX request)?

I believe these AJAX requests are a way of asking if Chromecast extension exists. Is there a better way to check if Chromecast extension exists?

Google Chromecast sender error if Chromecast extension is not installed or using incognito

In Chrome DevTools, under Rendering, there&#39;s an option to &quot;Show potential scroll bottlenecks&quot;.

When I enabled this, some `div` elements I have on the screen with `overflow:scroll` show a flag at the top saying &quot;repaints on scroll.&quot;

I can&#39;t find a lot of documentation on this feature, and I don&#39;t know whether it&#39;s something I can actually fix or improve upon, or just a statement of fact - the divs have content, and they do indeed scroll.




Can I do anything about &quot;repaints on scroll&quot; warning in Chrome for &quot;overflow:scroll&quot; div

Often I want to inspect an element (e.g. tooltip) that only appears when another element is mouse overed/entered.  The element that appears, is made visible via jQuery&#39;s mouseenter event. 

I can&#39;t inspect the tooltip, since the tooltip disappears when my mouse leaves the containing element. 

Is there a way to pause JS events so I could hover on the element, then pause the browser&#39;s JS, and successfully inspect it?

For an example, try inspecting Twitter bootstrap&#39;s tooltips: http://getbootstrap.com/javascript/#tooltips.

Content Type	Original Author	Original Content on Stackoverflow
Question	Matas Vaitkevicius	View Question on Stackoverflow
Solution 1 - Google Chrome	Matas Vaitkevicius	View Answer on Stackoverflow

Skip line while debugging in Chrome developer tools

Google Chrome Problem Overview

Google Chrome Solutions

Solution 1 - Google Chrome

Using Caret Package but Getting Error in library(e1071)

Does Order of Fields of Multi-Column Index in MySQL Matter

Attributions