Programs & Examples On #Crosstab

A cross tab, also known as a "pivot table", is a method of summarizing data in tabular form.   Typically, these have a category column in the left hand side, and multiple summary columns to the right. Each different category will have its own row.

MySQL - Rows to Columns

I'm sorry to say this and maybe I'm not solving your problem exactly but PostgreSQL is 10 years older than MySQL and is extremely advanced compared to MySQL and there's many ways to achieve this easily. Install PostgreSQL and execute this query

CREATE EXTENSION tablefunc;

then voila! And here's extensive documentation: PostgreSQL: Documentation: 9.1: tablefunc or this query

CREATE EXTENSION hstore;

then again voila! PostgreSQL: Documentation: 9.0: hstore

Postgres - Transpose Rows to Columns

Use crosstab() from the tablefunc module.

SELECT * FROM crosstab(
   $$SELECT user_id, user_name, rn, email_address
     FROM  (
        SELECT u.user_id, u.user_name, e.email_address
             , row_number() OVER (PARTITION BY u.user_id
                            ORDER BY e.creation_date DESC NULLS LAST) AS rn
        FROM   usr u
        LEFT   JOIN email_tbl e USING (user_id)
        ) sub
     WHERE  rn < 4
     ORDER  BY user_id
   $$
  , 'VALUES (1),(2),(3)'
   ) AS t (user_id int, user_name text, email1 text, email2 text, email3 text);

I used dollar-quoting for the first parameter, which has no special meaning. It's just convenient if you have to escape single quotes in the query string which is a common case:

Detailed explanation and instructions here:

And in particular, for "extra columns":

The special difficulties here are:

  • The lack of key names.
    -> We substitute with row_number() in a subquery.

  • The varying number of emails.
    -> We limit to a max. of three in the outer SELECT
    and use crosstab() with two parameters, providing a list of possible keys.

Pay attention to NULLS LAST in the ORDER BY.

PostgreSQL Crosstab Query

You can use the crosstab() function of the additional module tablefunc - which you have to install once per database. Since PostgreSQL 9.1 you can use CREATE EXTENSION for that:

CREATE EXTENSION tablefunc;

In your case, I believe it would look something like this:

CREATE TABLE t (Section CHAR(1), Status VARCHAR(10), Count integer);

INSERT INTO t VALUES ('A', 'Active',   1);
INSERT INTO t VALUES ('A', 'Inactive', 2);
INSERT INTO t VALUES ('B', 'Active',   4);
INSERT INTO t VALUES ('B', 'Inactive', 5);

SELECT row_name AS Section,
       category_1::integer AS Active,
       category_2::integer AS Inactive
FROM crosstab('select section::text, status, count::text from t',2)
            AS ct (row_name text, category_1 text, category_2 text);

Use async await with Array.map

I'd recommend using Promise.all as mentioned above, but if you really feel like avoiding that approach, you can do a for or any other loop:

const arr = [1,2,3,4,5];
let resultingArr = [];
for (let i in arr){
  await callAsynchronousOperation(i);
  resultingArr.push(i + 1)
}

Removing element from array in component state

I want to chime in here even though this question has already been answered correctly by @pscl in case anyone else runs into the same issue I did. Out of the 4 methods give I chose to use the es6 syntax with arrow functions due to it's conciseness and lack of dependence on external libraries:

Using Array.prototype.filter with ES6 Arrow Functions

removeItem(index) {
  this.setState((prevState) => ({
    data: prevState.data.filter((_, i) => i != index)
  }));
}

As you can see I made a slight modification to ignore the type of index (!== to !=) because in my case I was retrieving the index from a string field.

Another helpful point if you're seeing weird behavior when removing an element on the client side is to NEVER use the index of an array as the key for the element:

// bad
{content.map((content, index) =>
  <p key={index}>{content.Content}</p>
)}

When React diffs with the virtual DOM on a change, it will look at the keys to determine what has changed. So if you're using indices and there is one less in the array, it will remove the last one. Instead, use the id's of the content as keys, like this.

// good
{content.map(content =>
  <p key={content.id}>{content.Content}</p>
)}

The above is an excerpt from this answer from a related post.

Happy Coding Everyone!

Bootstrap 3 Flush footer to bottom. not fixed

use flexbox as you can use it at your disposal. The solution offered by bootstrap 4 still hunting overlap content in responsive layout, e.g: it will break in mobile view, i come across the most neat trick is to use flexbox solution demo shown at here:(https://philipwalton.github.io/solved-by-flexbox/demos/sticky-footer/) this way we do not have to deal with fixed height issue which is an obsolete solution by now...this solution works for bootstrap 3 and 4 whichever you using.

<body class="Site">
  <header>…</header>
  <main class="Site-content">…</main>
  <footer>…</footer>
</body>

.Site {
  display: flex;
  min-height: 100vh;
  flex-direction: column;
}

.Site-content {
  flex: 1;
}

Correctly ignore all files recursively under a specific folder except for a specific file type

This might look stupid, but check if you haven't already added the folder/files you are trying to ignore to the index before. If you did, it does not matter what you put in your .gitignore file, the folders/files will still be staged.

jQuery select change event get selected option

Another and short way to get value of selected value,

$('#selectElement').on('change',function(){
   var selectedVal = $(this).val();
                       ^^^^  ^^^^ -> presents #selectElement selected value 
                         |
                         v
               presents #selectElement, 
});

How to edit the legend entry of a chart in Excel?

Left Click on chart. «PivotTable Field List» will appear on right. On the right down quarter of PivotTable Field List (S Values), you see the names of the legends. Left Click on the legend name. Left Click on the «Value field settings». At the top there is «Source Name». You can’t change it. Below there is «Custom Name». Change the Custom Name as you wish. Now the legend name on the chart has the new name you gave.

Catch checked change event of a checkbox

use the click event for best compatibility with MSIE

$(document).ready(function() {
    $("input[type=checkbox]").click(function() {
        alert("state changed");
    });
});

How to get my Android device Internal Download Folder path

if a device has an SD card, you use:

Environment.getExternalStorageState() 

if you don't have an SD card, you use:

Environment.getDataDirectory()

if there is no SD card, you can create your own directory on the device locally.

    //if there is no SD card, create new directory objects to make directory on device
        if (Environment.getExternalStorageState() == null) {
                        //create new file directory object
            directory = new File(Environment.getDataDirectory()
                    + "/RobotiumTestLog/");
            photoDirectory = new File(Environment.getDataDirectory()
                    + "/Robotium-Screenshots/");
            /*
             * this checks to see if there are any previous test photo files
             * if there are any photos, they are deleted for the sake of
             * memory
             */
            if (photoDirectory.exists()) {
                File[] dirFiles = photoDirectory.listFiles();
                if (dirFiles.length != 0) {
                    for (int ii = 0; ii <= dirFiles.length; ii++) {
                        dirFiles[ii].delete();
                    }
                }
            }
            // if no directory exists, create new directory
            if (!directory.exists()) {
                directory.mkdir();
            }

            // if phone DOES have sd card
        } else if (Environment.getExternalStorageState() != null) {
            // search for directory on SD card
            directory = new File(Environment.getExternalStorageDirectory()
                    + "/RobotiumTestLog/");
            photoDirectory = new File(
                    Environment.getExternalStorageDirectory()
                            + "/Robotium-Screenshots/");
            if (photoDirectory.exists()) {
                File[] dirFiles = photoDirectory.listFiles();
                if (dirFiles.length > 0) {
                    for (int ii = 0; ii < dirFiles.length; ii++) {
                        dirFiles[ii].delete();
                    }
                    dirFiles = null;
                }
            }
            // if no directory exists, create new directory to store test
            // results
            if (!directory.exists()) {
                directory.mkdir();
            }
        }// end of SD card checking

add permissions on your manifest.xml

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

Happy coding..

How do you do block comments in YAML?

In Azure Devops browser(pipeline yaml editor),

Ctrl + K + C Comment Block

Ctrl + K + U Uncomment Block

There also a 'Toggle Block Comment' option but this did not work for me. enter image description here

There are other 'wierd' ways too: right click to see 'Command Palette' or F1

enter image description here

Then choose a cursor option. enter image description here

Now it is just a matter of #

or even smarter [Ctrl + k] + [Ctrl + c]

How to create a file name with the current date & time in Python?

While not using datetime, this solves your problem (answers your question) of getting a string with the current time and date format you specify:

import time
timestr = time.strftime("%Y%m%d-%H%M%S")
print timestr

yields:

20120515-155045

so your filename could append or use this string.

Is there are way to make a child DIV's width wider than the parent DIV using CSS?

Based on your suggestion original suggestion (setting negative margins), I have tried and come up with a similar method using percentage units for dynamic browser width:

HTML

<div class="grandparent">
    <div class="parent">
        <div class="child">
            <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Dolore neque repellat ipsum natus magni soluta explicabo architecto, molestias laboriosam rerum. Tempore eos labore temporibus alias necessitatibus illum enim, est harum perspiciatis, sit, totam earum corrupti placeat architecto aut minus dignissimos mollitia asperiores sint ea. Libero hic laudantium, ipsam nostrum earum distinctio. Cum expedita, ratione, accusamus dicta similique distinctio est dolore assumenda soluta dolorem quisquam ex possimus aliquid provident quo? Enim tempora quo cupiditate eveniet aperiam.</p>
        </div>
    </div>
</div>

CSS:

.child-div{
   margin: 0 -100%;
   padding: 0 -100%;
}

.parent {
    width: 60%;
    background-color: red;
    margin: 0 auto;
    padding: 50px;
    position:relative;
}

.grandparent {
        overflow-x:hidden;
        background-color: blue;
        width: 100%;
        position:relative;
    }

The negative margins will let the content flow out of the Parent DIV. Therefore I set the padding: 0 100%; to push the content back to the original boundaries of the Chlid DIV.

The negative margins will also make the .child-div's total width expands out of the browser's viewport, resulting in a horizontal scroll. Hence we need to clip the extruding width by applying an overflow-x: hidden to a Grandparent DIV (which is the parent of the Parent Div):

Here is the JSfiddle

I haved tried Nils Kaspersson's left: calc(-50vw + 50%); it worked perfectly fine in Chrome & FF (not sure about IE yet) until I found out Safari browsers doesn't do it properly. Hope they fixed this soon as I actually like this simple method.

This also may resolve your issue where the Parent DIV element has to be position:relative

The 2 drawbacks of this workaround method is:

  • Require extra markup (i.e a grandparent element (just like the good ol' table vertical align method isn't it...)
  • The left and right border of the Child DIV will never show, simply because they are outside of the browser's viewport.

Please let me know if there's any issue you find with this method ;). Hope it helps.

Failed to find 'ANDROID_HOME' environment variable

I experienced same issue on MAC catalina 10.15 what you add in .bash_profile is not recognised when you echo it on terminal, it is stored temporarily. It is recommended to use .zprofile for permanent and add all environment variables in it.After trying for 5hours i found out this solution. Hope it will be useful for someone.

 vi .zprofile
 insert(press i)

export ANDROID_HOME=/Users/mypc/Library/Android/sdk
export PATH=$ANDROID_HOME/platform-tools:${PATH}

after adding environment variables press esc
then enter :wq!
try echo $ANDROID_HOME in new tab(it will not be empty) path will be 
printed

"An attempt was made to access a socket in a way forbidden by its access permissions" while using SMTP

If the other answers don't work you can check if something else is using the port with netstat:

netstat -ano | findstr <your port number>

If nothing is already using it, the port might be excluded, try this command to see if the range is blocked by something else:

netsh interface ipv4 show excludedportrange protocol=tcp

Determining type of an object in ruby

you could also try: instance_of?

p 1.instance_of? Fixnum    #=> True
p "1".instance_of? String  #=> True
p [1,2].instance_of? Array #=> True

How can I replace a newline (\n) using sed?

To remove empty lines:

sed -n "s/^$//;t;p;"

Finding the direction of scrolling in a UIScrollView?

In all upper answers two major ways to solve the problem is using panGestureRecognizer or contentOffset. Both methods have their cons and pros.

Method 1: panGestureRecognizer

When you use panGestureRecognizer like what @followben suggested, if you don't want to programmatically scroll your scroll view, it works properly.

- (void)scrollViewWillBeginDragging:(UIScrollView *)scrollView
{ 
    if ([scrollView.panGestureRecognizer translationInView:scrollView.superview].x > 0) {
        // handle dragging to the right
    } else {
        // handle dragging to the left
    }
}

Cons

But if you move scroll view with following code, upper code can not recognize it:

setContentOffset(CGPoint(x: 100, y: 0), animation: false)

Method 2: contentOffset

var lastContentOffset: CGPoint = CGPoint.zero

func scrollViewDidScroll(_ scrollView: UIScrollView) {
    if (self.lastContentOffset.x > scrollView.contentOffset.x) {
        // scroll to right
    } else if self.lastContentOffset.x < scrollView.contentOffset.x {
        // scroll to left
    }
    self.lastContentOffset = self.scrollView.contentOffset
}

Cons

If you want to change contentOffset programmatically, during scroll (like when you want to create infinite scroll), this method makes problem, because you might change contentOffset during changing content views places and in this time, upper code jump in that you scroll to right or left.

How to rename with prefix/suffix?

In my case I have a group of files which needs to be renamed before I can work with them. Each file has its own role in group and has its own pattern.

As result I have a list of rename commands like this:

f=`ls *canctn[0-9]*`   ;  mv $f  CNLC.$f
f=`ls *acustb[0-9]*`   ;  mv $f  CATB.$f
f=`ls *accusgtb[0-9]*` ;  mv $f  CATB.$f
f=`ls *acus[0-9]*`     ;  mv $f  CAUS.$f

Try this also :

f=MyFileName; mv $f {pref1,pref2}$f{suf1,suf2}

This will produce all combinations with prefixes and suffixes:

pref1.MyFileName.suf1
...
pref2.MyFileName.suf2

Another way to solve same problem is to create mapping array and add corespondent prefix for each file type as shown below:

#!/bin/bash
unset masks
typeset -A masks
masks[ip[0-9]]=ip
masks[iaf_usg[0-9]]=ip_usg
masks[ipusg[0-9]]=ip_usg
...
for fileMask in ${!masks[*]}; 
do  
registryEntry="${masks[$fileMask]}";
fileName=*${fileMask}*
[ -e ${fileName} ] &&  mv ${fileName} ${registryEntry}.${fileName}  
done

What is Cache-Control: private?

Cache-Control: private

Indicates that all or part of the response message is intended for a single user and MUST NOT be cached by a shared cache, such as a proxy server.

From RFC2616 section 14.9.1

How exactly does __attribute__((constructor)) work?

Here is a "concrete" (and possibly useful) example of how, why, and when to use these handy, yet unsightly constructs...

Xcode uses a "global" "user default" to decide which XCTestObserver class spews it's heart out to the beleaguered console.

In this example... when I implicitly load this psuedo-library, let's call it... libdemure.a, via a flag in my test target á la..

OTHER_LDFLAGS = -ldemure

I want to..

  1. At load (ie. when XCTest loads my test bundle), override the "default" XCTest "observer" class... (via the constructor function) PS: As far as I can tell.. anything done here could be done with equivalent effect inside my class' + (void) load { ... } method.

  2. run my tests.... in this case, with less inane verbosity in the logs (implementation upon request)

  3. Return the "global" XCTestObserver class to it's pristine state.. so as not to foul up other XCTest runs which haven't gotten on the bandwagon (aka. linked to libdemure.a). I guess this historically was done in dealloc.. but I'm not about to start messing with that old hag.

So...

#define USER_DEFS NSUserDefaults.standardUserDefaults

@interface      DemureTestObserver : XCTestObserver @end
@implementation DemureTestObserver

__attribute__((constructor)) static void hijack_observer() {

/*! here I totally hijack the default logging, but you CAN
    use multiple observers, just CSV them, 
    i.e. "@"DemureTestObserverm,XCTestLog"
*/
  [USER_DEFS setObject:@"DemureTestObserver" 
                forKey:@"XCTestObserverClass"];
  [USER_DEFS synchronize];
}

__attribute__((destructor)) static void reset_observer()  {

  // Clean up, and it's as if we had never been here.
  [USER_DEFS setObject:@"XCTestLog" 
                forKey:@"XCTestObserverClass"];
  [USER_DEFS synchronize];
}

...
@end

Without the linker flag... (Fashion-police swarm Cupertino demanding retribution, yet Apple's default prevails, as is desired, here)

enter image description here

WITH the -ldemure.a linker flag... (Comprehensible results, gasp... "thanks constructor/destructor"... Crowd cheers) enter image description here

How can I show the table structure in SQL Server query?

Another way is,

mysql > SHOW CREATE TABLE my_db.my_table;

You should get the table name and create table sql

Internal Error 500 Apache, but nothing in the logs?

The answers by @eric-leschinski is correct.

But there is another case if your Server API is FPM/FastCGI (Default on Centos 8 or you can check use phpinfo() function)

In this case:

  1. Run phpinfo() in a php file;
  2. Looking for Loaded Configuration File param to see where is config file for your PHP.
  3. Edit config file like @eric-leschinski 's answer.
  4. Check Server API param. If your server only use apache handle API -> restart apache. If your server use php-fpm you must restart php-fpm service

    systemctl restart php-fpm

    Check the log file in php-fpm log folder. eg /var/log/php-fpm/www-error.log

Angular HttpClient "Http failure during parsing"

if you have options

return this.http.post(`${this.endpoint}/account/login`,payload, { ...options, responseType: 'text' })

How to increment datetime by custom months in python without using library

Well with some tweaks and use of timedelta here we go:

from datetime import datetime, timedelta


def inc_date(origin_date):
    day = origin_date.day
    month = origin_date.month
    year = origin_date.year
    if origin_date.month == 12:
        delta = datetime(year + 1, 1, day) - origin_date
    else:
        delta = datetime(year, month + 1, day) - origin_date
    return origin_date + delta

final_date = inc_date(datetime.today())
print final_date.date()

SELECT * FROM multiple tables. MySQL

What you do here is called a JOIN (although you do it implicitly because you select from multiple tables). This means, if you didn't put any conditions in your WHERE clause, you had all combinations of those tables. Only with your condition you restrict your join to those rows where the drink id matches.

But there are still X multiple rows in the result for every drink, if there are X photos with this particular drinks_id. Your statement doesn't restrict which photo(s) you want to have!

If you only want one row per drink, you have to tell SQL what you want to do if there are multiple rows with a particular drinks_id. For this you need grouping and an aggregate function. You tell SQL which entries you want to group together (for example all equal drinks_ids) and in the SELECT, you have to tell which of the distinct entries for each grouped result row should be taken. For numbers, this can be average, minimum, maximum (to name some).

In your case, I can't see the sense to query the photos for drinks if you only want one row. You probably thought you could have an array of photos in your result for each drink, but SQL can't do this. If you only want any photo and you don't care which you'll get, just group by the drinks_id (in order to get only one row per drink):

SELECT name, price, photo
FROM drinks, drinks_photos
WHERE drinks.id = drinks_id 
GROUP BY drinks_id

name     price   photo
fanta    5       ./images/fanta-1.jpg
dew      4       ./images/dew-1.jpg

In MySQL, we also have GROUP_CONCAT, if you want the file names to be concatenated to one single string:

SELECT name, price, GROUP_CONCAT(photo, ',')
FROM drinks, drinks_photos
WHERE drinks.id = drinks_id 
GROUP BY drinks_id

name     price   photo
fanta    5       ./images/fanta-1.jpg,./images/fanta-2.jpg,./images/fanta-3.jpg
dew      4       ./images/dew-1.jpg,./images/dew-2.jpg

However, this can get dangerous if you have , within the field values, since most likely you want to split this again on the client side. It is also not a standard SQL aggregate function.

Android SDK installation doesn't find JDK

I downloaded the .zip archive instead and ran SDK Manager.exe, and it worked like a charm. You had the same issue with the .exe otherwise.

uint8_t vs unsigned char

On almost every system I've met uint8_t == unsigned char, but this is not guaranteed by the C standard. If you are trying to write portable code and it matters exactly what size the memory is, use uint8_t. Otherwise use unsigned char.

How do you clear the SQL Server transaction log?

Below is a script to shrink the transaction log, but I’d definitely recommend backing up the transaction log before shrinking it.

If you just shrink the file you are going to lose a ton of data that may come as a life saver in case of disaster. The transaction log contains a lot of useful data that can be read using a third-party transaction log reader (it can be read manually but with extreme effort though).

The transaction log is also a must when it comes to point in time recovery, so don’t just throw it away, but make sure you back it up beforehand.

Here are several posts where people used data stored in the transaction log to accomplish recovery:

 

USE DATABASE_NAME;
GO

ALTER DATABASE DATABASE_NAME
SET RECOVERY SIMPLE;
GO
--First parameter is log file name and second is size in MB
DBCC SHRINKFILE (DATABASE_NAME_Log, 1);

ALTER DATABASE DATABASE_NAME
SET RECOVERY FULL;
GO

You may get an error that looks like this when the executing commands above

“Cannot shrink log file (log file name) because the logical log file located at the end of the file is in use“

This means that TLOG is in use. In this case try executing this several times in a row or find a way to reduce database activities.

get all keys set in memcached

Found a way, thanks to the link here (with the original google group discussion here)

First, Telnet to your server:

telnet 127.0.0.1 11211

Next, list the items to get the slab ids:

stats items
STAT items:3:number 1
STAT items:3:age 498
STAT items:22:number 1
STAT items:22:age 498
END

The first number after ‘items’ is the slab id. Request a cache dump for each slab id, with a limit for the max number of keys to dump:

stats cachedump 3 100
ITEM views.decorators.cache.cache_header..cc7d9 [6 b; 1256056128 s]
END

stats cachedump 22 100
ITEM views.decorators.cache.cache_page..8427e [7736 b; 1256056128 s]
END

How to retrieve the LoaderException property?

catch (ReflectionTypeLoadException ex)
{        
    foreach (var item in ex.LoaderExceptions)
    {
          MessageBox.Show(item.Message);                    
    }
}

I'm sorry for resurrecting an old thread, but wanted to post a different solution to pull the loader exception (Using the actual ReflectionTypeLoadException) for anybody else to come across this.

How do I include a path to libraries in g++

In your MakeFile or CMakeLists.txt you can set CMAKE_CXX_FLAGS as below:

set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -I/path/to/your/folder")

Submit Button Image

<input type="image" src="path to image" name="submit" />

UPDATE:

For button states, you can use type="submit" and then add a class to it

<input type="submit" name="submit" class="states" />

Then in css, use background images for:

.states{
background-image:url(path to url);
height:...;
width:...;
}

.states:hover{
background-position:...;
}

.states:active{
background-position:...;
}

From an array of objects, extract value of a property as array

Yes, but it relies on an ES5 feature of JavaScript. This means it will not work in IE8 or older.

var result = objArray.map(function(a) {return a.foo;});

On ES6 compatible JS interpreters you can use an arrow function for brevity:

var result = objArray.map(a => a.foo);

Array.prototype.map documentation

Learning Regular Expressions

The most important part is the concepts. Once you understand how the building blocks work, differences in syntax amount to little more than mild dialects. A layer on top of your regular expression engine's syntax is the syntax of the programming language you're using. Languages such as Perl remove most of this complication, but you'll have to keep in mind other considerations if you're using regular expressions in a C program.

If you think of regular expressions as building blocks that you can mix and match as you please, it helps you learn how to write and debug your own patterns but also how to understand patterns written by others.

Start simple

Conceptually, the simplest regular expressions are literal characters. The pattern N matches the character 'N'.

Regular expressions next to each other match sequences. For example, the pattern Nick matches the sequence 'N' followed by 'i' followed by 'c' followed by 'k'.

If you've ever used grep on Unix—even if only to search for ordinary looking strings—you've already been using regular expressions! (The re in grep refers to regular expressions.)

Order from the menu

Adding just a little complexity, you can match either 'Nick' or 'nick' with the pattern [Nn]ick. The part in square brackets is a character class, which means it matches exactly one of the enclosed characters. You can also use ranges in character classes, so [a-c] matches either 'a' or 'b' or 'c'.

The pattern . is special: rather than matching a literal dot only, it matches any character. It's the same conceptually as the really big character class [-.?+%$A-Za-z0-9...].

Think of character classes as menus: pick just one.

Helpful shortcuts

Using . can save you lots of typing, and there are other shortcuts for common patterns. Say you want to match a digit: one way to write that is [0-9]. Digits are a frequent match target, so you could instead use the shortcut \d. Others are \s (whitespace) and \w (word characters: alphanumerics or underscore).

The uppercased variants are their complements, so \S matches any non-whitespace character, for example.

Once is not enough

From there, you can repeat parts of your pattern with quantifiers. For example, the pattern ab?c matches 'abc' or 'ac' because the ? quantifier makes the subpattern it modifies optional. Other quantifiers are

  • * (zero or more times)
  • + (one or more times)
  • {n} (exactly n times)
  • {n,} (at least n times)
  • {n,m} (at least n times but no more than m times)

Putting some of these blocks together, the pattern [Nn]*ick matches all of

  • ick
  • Nick
  • nick
  • Nnick
  • nNick
  • nnick
  • (and so on)

The first match demonstrates an important lesson: * always succeeds! Any pattern can match zero times.

A few other useful examples:

  • [0-9]+ (and its equivalent \d+) matches any non-negative integer
  • \d{4}-\d{2}-\d{2} matches dates formatted like 2019-01-01

Grouping

A quantifier modifies the pattern to its immediate left. You might expect 0abc+0 to match '0abc0', '0abcabc0', and so forth, but the pattern immediately to the left of the plus quantifier is c. This means 0abc+0 matches '0abc0', '0abcc0', '0abccc0', and so on.

To match one or more sequences of 'abc' with zeros on the ends, use 0(abc)+0. The parentheses denote a subpattern that can be quantified as a unit. It's also common for regular expression engines to save or "capture" the portion of the input text that matches a parenthesized group. Extracting bits this way is much more flexible and less error-prone than counting indices and substr.

Alternation

Earlier, we saw one way to match either 'Nick' or 'nick'. Another is with alternation as in Nick|nick. Remember that alternation includes everything to its left and everything to its right. Use grouping parentheses to limit the scope of |, e.g., (Nick|nick).

For another example, you could equivalently write [a-c] as a|b|c, but this is likely to be suboptimal because many implementations assume alternatives will have lengths greater than 1.

Escaping

Although some characters match themselves, others have special meanings. The pattern \d+ doesn't match backslash followed by lowercase D followed by a plus sign: to get that, we'd use \\d\+. A backslash removes the special meaning from the following character.

Greediness

Regular expression quantifiers are greedy. This means they match as much text as they possibly can while allowing the entire pattern to match successfully.

For example, say the input is

"Hello," she said, "How are you?"

You might expect ".+" to match only 'Hello,' and will then be surprised when you see that it matched from 'Hello' all the way through 'you?'.

To switch from greedy to what you might think of as cautious, add an extra ? to the quantifier. Now you understand how \((.+?)\), the example from your question works. It matches the sequence of a literal left-parenthesis, followed by one or more characters, and terminated by a right-parenthesis.

If your input is '(123) (456)', then the first capture will be '123'. Non-greedy quantifiers want to allow the rest of the pattern to start matching as soon as possible.

(As to your confusion, I don't know of any regular-expression dialect where ((.+?)) would do the same thing. I suspect something got lost in transmission somewhere along the way.)

Anchors

Use the special pattern ^ to match only at the beginning of your input and $ to match only at the end. Making "bookends" with your patterns where you say, "I know what's at the front and back, but give me everything between" is a useful technique.

Say you want to match comments of the form

-- This is a comment --

you'd write ^--\s+(.+)\s+--$.

Build your own

Regular expressions are recursive, so now that you understand these basic rules, you can combine them however you like.

Tools for writing and debugging regexes:

Books

Free resources

Footnote

†: The statement above that . matches any character is a simplification for pedagogical purposes that is not strictly true. Dot matches any character except newline, "\n", but in practice you rarely expect a pattern such as .+ to cross a newline boundary. Perl regexes have a /s switch and Java Pattern.DOTALL, for example, to make . match any character at all. For languages that don't have such a feature, you can use something like [\s\S] to match "any whitespace or any non-whitespace", in other words anything.

Get the short Git version hash

A really simple way is to:

git describe --always

Reordering arrays

Immutable version, no side effects (doesn’t mutate original array):

const testArr = [1, 2, 3, 4, 5];

function move(from, to, arr) {
    const newArr = [...arr];

    const item = newArr.splice(from, 1)[0];
    newArr.splice(to, 0, item);

    return newArr;
}

console.log(move(3, 1, testArr));

// [1, 4, 2, 3, 5]

codepen: https://codepen.io/mliq/pen/KKNyJZr

How do I disable right click on my web page?

You can do that with JavaScript by adding an event listener for the "contextmenu" event and calling the preventDefault() method:

document.addEventListener('contextmenu', event => event.preventDefault());

That being said: DON'T DO IT.

Why? Because it achieves nothing other than annoying users. Also many browsers have a security option to disallow disabling of the right click (context) menu anyway.

Not sure why you'd want to. If it's out of some misplaced belief that you can protect your source code or images that way, think again: you can't.

Select multiple value in DropDownList using ASP.NET and C#

Take a look at the ListBox control to allow multi-select.

<asp:ListBox runat="server" ID="lblMultiSelect" SelectionMode="multiple">
            <asp:ListItem Text="opt1" Value="opt1" />
            <asp:ListItem Text="opt2" Value="opt2" />
            <asp:ListItem Text="opt3" Value="opt3" />
</asp:ListBox> 

in the code behind

foreach(ListItem listItem in lblMultiSelect.Items)
    {
       if (listItem.Selected)
       {
          var val = listItem.Value;
          var txt = listItem.Text; 
       }
    }

how to reset <input type = "file">

You should try this:

$("#uploadCaptureInputFile").val('');

Command not found after npm install in zsh

In my humble opinion, first, you have to make sure you have any kind of Node version installed. For that type:

nvm ls

And if you don't get any versions it means I was right :) Then you have to type:

nvm install <node_version**>

** the actual version you can find in Node website

Then you will have Node and you will be able to use npm commands

How to define Typescript Map of key value pair. where key is a number and value is an array of objects

The most simple way is to use Record type Record<number, productDetails >

interface productDetails {
   productId : number , 
   price : number , 
   discount : number
};

const myVar : Record<number, productDetails> = {
   1: {
       productId : number , 
       price : number , 
       discount : number
   }
}

How line ending conversions work with git core.autocrlf between different operating systems

No, the @jmlane answer is wrong.

For Checkin (git add, git commit):

  1. if text property is Set, Set value to 'auto', the conversion happens enen the file has been committed with 'CRLF'
  2. if text property is Unset:nothing happens, enen for Checkout
  3. if text property is Unspecified, conversion depends on core.autocrlf
    1. if autocrlf = input or autocrlf = true, the conversion only happens when the file in the repository is 'LF', if it has been 'CRLF', nothing will happens.
    2. if autocrlf = false, nothing happens

For Checkout:

  1. if text property is Unset: nothing happens.
  2. if text property is Set, Set value to 'auto: it depends on core.autocrlf, core.eol.
    1. core.autocrlf = input : nothing happens
    2. core.autocrlf = true : the conversion only happens when the file in the repository is 'LF', 'LF' -> 'CRLF'
    3. core.autocrlf = false : the conversion only happens when the file in the repository is 'LF', 'LF' -> core.eol
  3. if text property is Unspecified, it depends on core.autocrlf.
    1. the same as 2.1
    2. the same as 2.2
    3. None, nothing happens, core.eol is not effective when text property is Unspecified

Default behavior

So the Default behavior is text property is Unspecified and core.autocrlf = false:

  1. for checkin, nothing happens
  2. for checkout, nothing happens

Conclusions

  1. if text property is set, checkin behavior is depends on itself, not on autocrlf
  2. autocrlf or core.eol is for checkout behavior, and autocrlf > core.eol

Using IF ELSE in Oracle

IF is a PL/SQL construct. If you are executing a query, you are using SQL not PL/SQL.

In SQL, you can use a CASE statement in the query itself

SELECT DISTINCT a.item, 
                (CASE WHEN b.salesman = 'VIKKIE'
                      THEN 'ICKY'
                      ELSE b.salesman
                  END), 
                NVL(a.manufacturer,'Not Set') Manufacturer
  FROM inv_items a, 
       arv_sales b
 WHERE  a.co = '100'
   AND a.co = b.co
   AND A.ITEM_KEY = b.item_key   
   AND a.item LIKE 'BX%'
   AND b.salesman in ('01','15')
   AND trans_date BETWEEN to_date('010113','mmddrr')
                      and to_date('011713','mmddrr')
ORDER BY a.item

Since you aren't doing any aggregation, you don't want a GROUP BY in your query. Are you really sure that you need the DISTINCT? People often throw that in haphazardly or add it when they are missing a join condition rather than considering whether it is really necessary to do the extra work to identify and remove duplicates.

How can I reverse a NSArray in Objective-C?

If all you want to do is iterate in reverse, try this:

// iterate backwards
nextIndex = (currentIndex == 0) ? [myArray count] - 1 : (currentIndex - 1) % [myArray count];

You can do the [myArrayCount] once and save it to a local variable (I think its expensive), but I’m also guessing that the compiler will pretty much do the same thing with the code as written above.

IsNothing versus Is Nothing

You should absolutely avoid using IsNothing()

Here are 4 reasons from the article IsNothing() VS Is Nothing

  1. Most importantly, IsNothing(object) has everything passed to it as an object, even value types! Since value types cannot be Nothing, it’s a completely wasted check.
    Take the following example:

    Dim i As Integer
    If IsNothing(i) Then
       ' Do something 
    End If
    

    This will compile and run fine, whereas this:

    Dim i As Integer
    If i Is Nothing Then
        '   Do something 
    End If
    

    Will not compile, instead the compiler will raise the error:

    'Is' operator does not accept operands of type 'Integer'.
    Operands must be reference or nullable types.

  2. IsNothing(object) is actually part of part of the Microsoft.VisualBasic.dll.
    This is undesirable as you have an unneeded dependency on the VisualBasic library.

  3. Its slow - 33.76% slower in fact (over 1000000000 iterations)!

  4. Perhaps personal preference, but IsNothing() reads like a Yoda Condition. When you look at a variable you're checking it's state, with it as the subject of your investigation.

    i.e. does it do x? --- NOT Is xing a property of it?

    So I think If a IsNot Nothing reads better than If Not IsNothing(a)

How to Insert BOOL Value to MySQL Database

TRUE and FALSE are keywords, and should not be quoted as strings:

INSERT INTO first VALUES (NULL, 'G22', TRUE);
INSERT INTO first VALUES (NULL, 'G23', FALSE);

By quoting them as strings, MySQL will then cast them to their integer equivalent (since booleans are really just a one-byte INT in MySQL), which translates into zero for any non-numeric string. Thus, you get 0 for both values in your table.

Non-numeric strings cast to zero:

mysql> SELECT CAST('TRUE' AS SIGNED), CAST('FALSE' AS SIGNED), CAST('12345' AS SIGNED);
+------------------------+-------------------------+-------------------------+
| CAST('TRUE' AS SIGNED) | CAST('FALSE' AS SIGNED) | CAST('12345' AS SIGNED) |
+------------------------+-------------------------+-------------------------+
|                      0 |                       0 |                   12345 |
+------------------------+-------------------------+-------------------------+

But the keywords return their corresponding INT representation:

mysql> SELECT TRUE, FALSE;
+------+-------+
| TRUE | FALSE |
+------+-------+
|    1 |     0 |
+------+-------+

Note also, that I have replaced your double-quotes with single quotes as are more standard SQL string enclosures. Finally, I have replaced your empty strings for id with NULL. The empty string may issue a warning.

How do I use regular expressions in bash scripts?

You need spaces around the operator =~

i="test"
if [[ $i =~ "200[78]" ]];
then
  echo "OK"
else
  echo "not OK"
fi

Replace all spaces in a string with '+'

Use a regular expression with the g modifier:

var replaced = str.replace(/ /g, '+');

From Using Regular Expressions with JavaScript and ActionScript:

/g enables "global" matching. When using the replace() method, specify this modifier to replace all matches, rather than only the first one.

This Activity already has an action bar supplied by the window decor

Simply put, you can do the following:-

if (android.os.Build.VERSION.SDK_INT >= 21) {
        Window window = getWindow();
        window.addFlags(WindowManager.LayoutParams.FLAG_DRAWS_SYSTEM_BAR_BACKGROUNDS);
        window.clearFlags(WindowManager.LayoutParams.FLAG_TRANSLUCENT_STATUS);
        window.setStatusBarColor(getResources().getColor(R.color.colorPrimaryDark));

    }

Add a properties file to IntelliJ's classpath

Actually, you have at least 2 ways to do it, the first way is described by ColinD, you just configure the "resources" folder as Sources folder in IDEA. If the Resource Patterns contains the extension of your resource, then it will be copied to the output directory when you Make the project and output directory is automatically a classpath of your application.

Another common way is to add the "resources" folder to the classpath directly. Go to Project Structure | Modules | Your Module | Dependencies, click Add, Single-Entry Module Library, specify the path to the "resources" folder.

Yet another solution would be to put the log4j.properties file directly under the Source root of your project (in the default package directory). It's the same as the first way except you don't need to add another Source root in the Module Paths settings, the file will be copied to the output directory on Make.

If you want to test with different log4j configurations, it may be easier to specify a custom configuration file directly in the Run/Debug configuration, VM parameters filed like:

-Dlog4j.configuration=file:/c:/log4j.properties.

Selecting Multiple Values from a Dropdown List in Google Spreadsheet

You would use data validation for this. Click in the cell you want to have a multiple drop down > DATA > Validation > Criteria (List from a Range) - here you select form a list of items you want in the drop down. And .. you are good. I have included an example to reference.

What do the return values of Comparable.compareTo mean in Java?

Answer in short: (search your situation)

  • 1.compareTo(0) (return: 1)
  • 1.compareTo(1) (return: 0)
  • 0.comapreTo(1) (return: -1)

Vue template or render function not defined yet I am using neither?

If someone else keeps getting the same error. Just add one extra div in your component template.

As the documentation says:

Component template should contain exactly one root element

Check this simple example:

 import yourComponent from '{path to component}'
    export default {
        components: {
            yourComponent
        },
}

 // Child component
 <template>
     <div> This is the one! </div>
 </template>

web.xml is missing and <failOnMissingWebXml> is set to true

I have the same problem. After studying and googling, I have resolved my problem:

Right click on the project folder, go to Java EE Tools, select Generate Deployment Descriptor Stub. This will create web.xml in the folder src/main/webapp/WEB-INF.

How do I pass multiple parameters into a function in PowerShell?

You call PowerShell functions without the parentheses and without using the comma as a separator. Try using:

test "ABC" "DEF"

In PowerShell the comma (,) is an array operator, e.g.

$a = "one", "two", "three"

It sets $a to an array with three values.

Adb Devices can't find my phone

I did the following to get my Mac to see the devices again:

  • Run android update adb
  • Run adb kill-server
  • Run adb start-server

At this point, calling adb devices started returning devices again. Now run or debug your project to test it on your device.

Android ListView in fragment example

Your Fragment can subclass ListFragment.
And onCreateView() from ListFragment will return a ListView you can then populate.

Padding a table row

give the td padding

How to debug a bash script?

Some trick to debug scripts:

Using set -[nvx]

In addition to

set -x

and

set +x

for stopping dump.

I would like to speak about set -v wich dump as smaller as less developped output.

bash <<<$'set -x\nfor i in {0..9};do\n\techo $i\n\tdone\nset +x' 2>&1 >/dev/null|wc -l
21

for arg in x v n nx nv nvx;do echo "- opts: $arg"
    bash 2> >(wc -l|sed s/^/stderr:/) > >(wc -l|sed s/^/stdout:/) <<eof
        set -$arg
        for i in {0..9};do
            echo $i
          done
        set +$arg
        echo Done.
eof
    sleep .02
  done
- opts: x
stdout:11
stderr:21
- opts: v
stdout:11
stderr:4
- opts: n
stdout:0
stderr:0
- opts: nx
stdout:0
stderr:0
- opts: nv
stdout:0
stderr:5
- opts: nvx
stdout:0
stderr:5

Dump variables or tracing on the fly

For testing some variables, I use sometime this:

bash <(sed '18ideclare >&2 -p var1 var2' myscript.sh) args

for adding:

declare >&2 -p var1 var2

at line 18 and running resulting script (with args), without having to edit them.

of course, this could be used for adding set [+-][nvx]:

bash <(sed '18s/$/\ndeclare -p v1 v2 >\&2/;22s/^/set -x\n/;26s/^/set +x\n/' myscript) args

will add declare -p v1 v2 >&2 after line 18, set -x before line 22 and set +x before line 26.

little sample:

bash <(sed '2,3s/$/\ndeclare -p LINENO i v2 >\&2/;5s/^/set -x\n/;7s/^/set +x\n/' <(
        seq -f 'echo $@, $((i=%g))' 1 8)) arg1 arg2
arg1 arg2, 1
arg1 arg2, 2
declare -i LINENO="3"
declare -- i="2"
/dev/fd/63: line 3: declare: v2: not found
arg1 arg2, 3
declare -i LINENO="5"
declare -- i="3"
/dev/fd/63: line 5: declare: v2: not found
arg1 arg2, 4
+ echo arg1 arg2, 5
arg1 arg2, 5
+ echo arg1 arg2, 6
arg1 arg2, 6
+ set +x
arg1 arg2, 7
arg1 arg2, 8

Note: Care about $LINENO will be affected by on-the-fly modifications!

( To see resulting script whithout executing, simply drop bash <( and ) arg1 arg2 )

Step by step, execution time

Have a look at my answer about how to profile bash scripts

Looping over a list in Python

You may as well use for x in values rather than for x in values[:]; the latter makes an unnecessary copy. Also, of course that code checks for a length of 2 rather than of 3...

The code only prints one item per value of x - and x is iterating over the elements of values, which are the sublists. So it will only print each sublist once.

How to change the JDK for a Jenkins job?

There is a JDK dropdown in "job name" -> Configure in Jenkins web ui. It will list all JDKs available in Jenkins configuration.

Difference between arguments and parameters in Java

The term parameter refers to any declaration within the parentheses following the method/function name in a method/function declaration or definition; the term argument refers to any expression within the parentheses of a method/function call. i.e.

  1. parameter used in function/method definition.
  2. arguments used in function/method call.

Please have a look at the below example for better understanding:

package com.stackoverflow.works;

public class ArithmeticOperations {

    public static int add(int x, int y) { //x, y are parameters here
        return x + y;
    }

    public static void main(String[] args) {
        int x = 10;
        int y = 20;
        int sum = add(x, y); //x, y are arguments here
        System.out.println("SUM IS: " +sum);
    }

}

Thank you!

Use dynamic variable names in `dplyr`

I am also adding an answer that augments this a little bit because I came to this entry when searching for an answer, and this had almost what I needed, but I needed a bit more, which I got via @MrFlik 's answer and the R lazyeval vignettes.

I wanted to make a function that could take a dataframe and a vector of column names (as strings) that I want to be converted from a string to a Date object. I couldn't figure out how to make as.Date() take an argument that is a string and convert it to a column, so I did it as shown below.

Below is how I did this via SE mutate (mutate_()) and the .dots argument. Criticisms that make this better are welcome.

library(dplyr)

dat <- data.frame(a="leave alone",
                  dt="2015-08-03 00:00:00",
                  dt2="2015-01-20 00:00:00")

# This function takes a dataframe and list of column names
# that have strings that need to be
# converted to dates in the data frame
convertSelectDates <- function(df, dtnames=character(0)) {
    for (col in dtnames) {
        varval <- sprintf("as.Date(%s)", col)
        df <- df %>% mutate_(.dots= setNames(list(varval), col))
    }
    return(df)
}

dat <- convertSelectDates(dat, c("dt", "dt2"))
dat %>% str

how to align text vertically center in android

In relative layout you need specify textview height:

android:layout_height="100dp"

Or specify lines attribute:

android:lines="3"

HTML-Tooltip position relative to mouse pointer

One way to do this without JS is to use the hover action to reveal a HTML element that is otherwise hidden, see this codepen:

http://codepen.io/c0un7z3r0/pen/LZWXEw

Note that the span that contains the tooltip content is relative to the parent li. The magic is here:

ul#list_of_thrones li > span{
  display:none;
}
ul#list_of_thrones li:hover > span{
  position: absolute;
  display:block;
  ...
}

As you can see, the span is hidden unless the listitem is hovered over, thus revealing the span element, the span can contain as much html as you need. In the codepen attached I have also used a :after element for the arrow but that of course is entirely optional and has only been included in this example for cosmetic purposes.

I hope this helps, I felt compelled to post as all the other answers included JS solutions but the OP asked for a HTML/CSS only solution.

vertical divider between two columns in bootstrap

With Bootstrap 4 you can use borders, avoiding writing other CSS.

border-left

And if you want space between content and border you can use padding. (in this example padding left 4px)

pl-4

Example:

_x000D_
_x000D_
    <link href="https://stackpath.bootstrapcdn.com/bootstrap/4.4.1/css/bootstrap.min.css" rel="stylesheet"/>_x000D_
_x000D_
    <div class="row">_x000D_
      <div class="offset-6 border-left pl-4">First</div>_x000D_
      <div class="offset-6 border-left pl-4">Second</div>_x000D_
    </div>
_x000D_
_x000D_
_x000D_

Running Composer returns: "Could not open input file: composer.phar"

I had the same problem on Windows and used a different solution. I used the Composer_Setup.exe installation file supplied by the composer website and it does a global install.

After installing, make sure your PATH variable points to the directory where composer.phar is stored. This is usually C:\ProgramData\ComposerSetup\bin (ProgramData might be a hidden directory). It goes without saying, but also be sure that the PHP executable is also in your PATH variable.

You can then simply call

composer install

instead of

php composer.phar install

Overriding !important style

If you want to update / add single style in DOM Element style attribute you can use this function:

function setCssTextStyle(el, style, value) {
  var result = el.style.cssText.match(new RegExp("(?:[;\\s]|^)(" +
      style.replace("-", "\\-") + "\\s*:(.*?)(;|$))")),
    idx;
  if (result) {
    idx = result.index + result[0].indexOf(result[1]);
    el.style.cssText = el.style.cssText.substring(0, idx) +
      style + ": " + value + ";" +
      el.style.cssText.substring(idx + result[1].length);
  } else {
    el.style.cssText += " " + style + ": " + value + ";";
  }
}

style.cssText is supported for all major browsers.

Use case example:

var elem = document.getElementById("elementId");
setCssTextStyle(elem, "margin-top", "10px !important");

Here is link to demo

In SQL, how can you "group by" in ranges?

Try

SELECT (str(range) + "-" + str(range + 9) ) AS [Score range], COUNT(score) AS [number of occurances]
FROM (SELECT  score,  int(score / 10 ) * 10  AS range  FROM scoredata )  
GROUP BY range;

What is the easiest way to install BLAS and LAPACK for scipy?

Always for Ubuntu/Debian, chjortlund's answer it's very good but not perfect, since this way you get an unoptimized BLAS library. You have simply to do:

sudo apt install libatlas-base-dev

and voila'!

Source

Convert array into csv

Well maybe a little late after 4 years haha... but I was looking for solution to do OBJECT to CSV, however most solutions here is actually for ARRAY to CSV...

After some tinkering, here is my solution to convert object into CSV, I think is pretty neat. Hope this would help someone else.

$resp = array();
foreach ($entries as $entry) {
    $row = array();
    foreach ($entry as $key => $value) {
        array_push($row, $value);
    }
    array_push($resp, implode(',', $row));
}
echo implode(PHP_EOL, $resp);

Note that for the $key => $value to work, your object's attributes must be public, the private ones will not get fetched.

The end result is that you get something like this:

blah,blah,blah
blah,blah,blah

SQL multiple columns in IN clause

In general you can easily write the Where-Condition like this:

select * from tab1
where (col1, col2) in (select col1, col2 from tab2)

Note
Oracle ignores rows where one or more of the selected columns is NULL. In these cases you probably want to make use of the NVL-Funktion to map NULL to a special value (that should not be in the values):

select * from tab1
where (col1, NVL(col2, '---') in (select col1, NVL(col2, '---') from tab2)

What does functools.wraps do?

In short, functools.wraps is just a regular function. Let's consider this official example. With the help of the source code, we can see more details about the implementation and the running steps as follows:

  1. wraps(f) returns an object, say O1. It is an object of the class Partial
  2. The next step is @O1... which is the decorator notation in python. It means

wrapper=O1.__call__(wrapper)

Checking the implementation of __call__, we see that after this step, (the left hand side )wrapper becomes the object resulted by self.func(*self.args, *args, **newkeywords) Checking the creation of O1 in __new__, we know self.func is the function update_wrapper. It uses the parameter *args, the right hand side wrapper, as its 1st parameter. Checking the last step of update_wrapper, one can see the right hand side wrapper is returned, with some of attributes modified as needed.

Does Git Add have a verbose switch

You can use git add -i to get an interactive version of git add, although that's not exactly what you're after. The simplest thing to do is, after having git added, use git status to see what is staged or not.

Using git add . isn't really recommended unless it's your first commit. It's usually better to explicitly list the files you want staged, so that you don't start tracking unwanted files accidentally (temp files and such).

Stretch child div height to fill parent that has dynamic height

You can do it easily with a bit of jQuery

$(document).ready(function(){
  var parentHeight = $("#parentDiv").parent().height();
  $("#childDiv").height(parentHeight);
});

String, StringBuffer, and StringBuilder

In java, String is immutable. Being immutable we mean that once a String is created, we can not change its value. StringBuffer is mutable. Once a StringBuffer object is created, we just append the content to the value of object instead of creating a new object. StringBuilder is similar to StringBuffer but it is not thread-safe. Methods of StingBuilder are not synchronized but in comparison to other Strings, the Stringbuilder runs fastest. You can learn difference between String, StringBuilder and StringBuffer by implementing them.

EditText underline below text property

Use below code to change background color of edit-text's border.

Create new XML file under drawable.

abc.xml

<shape xmlns:android="http://schemas.android.com/apk/res/android"
    android:shape="rectangle">
    <solid android:color="#00000000" />
    <stroke android:width="1dip" android:color="#ffffff" />
</shape>

and add it as background of your edit-text

android:background="@drawable/abc"

CSS3 opacity gradient?

You can do it in CSS, but there isn't much support in browsers other than modern versions of Chrome, Safari and Opera at the moment. Firefox currently only supports SVG masks. See the Caniuse results for more information.

CSS:

p {
    color: red;
    -webkit-mask-image: -webkit-gradient(linear, left top, left bottom, 
    from(rgba(0,0,0,1)), to(rgba(0,0,0,0)));
}

The trick is to specify a mask that is itself a gradient that ends as invisible (thru alpha value)

See a demo with a solid background, but you can change this to whatever you want.

DEMO

Notice also that all the usual image properties are available for mask-image

_x000D_
_x000D_
p  {_x000D_
  color: red;_x000D_
  font-size: 30px;_x000D_
  -webkit-mask-image: linear-gradient(to left, rgba(0,0,0,1), rgba(0,0,0,0)), linear-gradient(to right, rgba(0,0,0,1), rgba(0,0,0,0));_x000D_
  -webkit-mask-size: 100% 50%;_x000D_
  -webkit-mask-repeat: no-repeat;_x000D_
  -webkit-mask-position: left top, left bottom;_x000D_
  }_x000D_
_x000D_
div {_x000D_
    background-color: lightblue;_x000D_
}
_x000D_
<div><p>text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text </p></div>
_x000D_
_x000D_
_x000D_

Now, another approach is available, that is supported by Chrome, Firefox, Safari and Opera.

The idea is to use

mix-blend-mode: hard-light;

that gives transparency if the color is gray. Then, a grey overlay on the element creates the transparency

_x000D_
_x000D_
div {_x000D_
  background-color: lightblue;_x000D_
}_x000D_
_x000D_
p {_x000D_
  color: red;_x000D_
  overflow: hidden;_x000D_
  position: relative;_x000D_
  width: 200px;_x000D_
  mix-blend-mode: hard-light;_x000D_
}_x000D_
_x000D_
p::after {_x000D_
  position: absolute;_x000D_
  content: "";_x000D_
  left: 0px;_x000D_
  top: 0px;_x000D_
  height: 100%;_x000D_
  width: 100%;_x000D_
  background: linear-gradient(transparent, gray);_x000D_
  pointer-events: none;_x000D_
}
_x000D_
<div><p>text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text </p></div>
_x000D_
_x000D_
_x000D_

Why is Dictionary preferred over Hashtable in C#?

Since .NET Framework 3.5 there is also a HashSet<T> which provides all the pros of the Dictionary<TKey, TValue> if you need only the keys and no values.

So if you use a Dictionary<MyType, object> and always set the value to null to simulate the type safe hash table you should maybe consider switching to the HashSet<T>.

Truststore and Keystore Definitions

  1. First and major difference between trustStore and keyStore is that trustStore is used by TrustManager to determine whether remote connection should be trusted, keyStore is used from KeyManager deciding which authentication credentials should be sent to the remote host for authentication during SSL handshake.

  2. Another difference is that keyStore theoretically contains private keys required only if you are running a Server in SSL connection or you have enabled client authentication on server side and on the other hand trustStore stores public key or certificates from CA (Certificate Authorities) which are used to trust remote party or SSL connection.

    In fact you can store in the same file both private and public keys, given that the the tool to manage those file is the same (keytool), so you could use a single file for both the purposes, but you probably should not.

  3. At least on my Mac OSX the default keyStore is ${user.home}/.keystore, and the default trustStore is /System/Library/Java/Support/CoreDeploy.bundle/Contents/Home/lib/security/cacerts.

    If you want to override them you should add the JVM parameters -Djavax.net.ssl.keyStore /path/to/keyStore or -Djavax.net.ssl.trustStore /path/to/trustStore. You might also need to set the keyStore password in case of java.security.UnrecoverableKeyException: Password must not be null, using the parameter -Djavax.net.ssl.trustStorePassword=password or -Djavax.net.ssl.trustStorePassword=password

Main Source:

http://javarevisited.blogspot.co.uk/2012/09/difference-between-truststore-vs-keyStore-Java-SSL.html

How to access SVG elements with Javascript

In case you use jQuery you need to wait for $(window).load, because the embedded SVG document might not be yet loaded at $(document).ready

$(window).load(function () {

    //alert("Document loaded, including graphics and embedded documents (like SVG)");
    var a = document.getElementById("alphasvg");

    //get the inner DOM of alpha.svg
    var svgDoc = a.contentDocument;

    //get the inner element by id
    var delta = svgDoc.getElementById("delta");
    delta.addEventListener("mousedown", function(){ alert('hello world!')}, false);
});

Bulk load data conversion error (type mismatch or invalid character for the specified codepage) for row 1, column 4 (Year)

Added MSSQLSERVER full access to the folder, diskadmin and bulkadmin server roles.

In my c# application, when preparing for the bulk insert command,

string strsql = "BULK INSERT PWCR_Contractor_vw_TEST FROM '" + strFileName + "' WITH (FIELDTERMINATOR = ',', ROWTERMINATOR = '\\n')";

And I get this error - Bulk load data conversion error (type mismatch or invalid character for the specified codepage) for row 1, column 8 (STATUS).

I looked at my logfile and found that the terminator becomes ' ' instead of '\n'. The OLE DB provider "BULK" for linked server "(null)" reported an error. The provider did not give any information about the error:

Cannot fetch a row from OLE DB provider "BULK" for linked server "(null)". Query :BULK INSERT PWCR_Contractor_vw_TEST FROM 'G:\NEWSTAGEWWW\CalAtlasToPWCR\Results\parsedRegistration.csv' WITH (FIELDTERMINATOR = ',', **ROWTERMINATOR = ''**)

So I added extra escape to the rowterminator - string strsql = "BULK INSERT PWCR_Contractor_vw_TEST FROM '" + strFileName + "' WITH (FIELDTERMINATOR = ',', ROWTERMINATOR = '\\n')";

And now it inserts successfully.

Bulk Insert SQL -   --->  BULK INSERT PWCR_Contractor_vw_TEST FROM 'G:\\NEWSTAGEWWW\\CalAtlasToPWCR\\Results\\parsedRegistration.csv' WITH (FIELDTERMINATOR = ',', ROWTERMINATOR = '\n')
Bulk Insert to PWCR_Contractor_vw_TEST successful...  --->  clsDatase.PerformBulkInsert

jQuery - find child with a specific class

$(this).find(".bgHeaderH2").html();

or

$(this).find(".bgHeaderH2").text();

Printing one character at a time from a string, using the while loop

Python allows you to use a string as an iterator:

for character in 'string':
    print(character)

I'm guessing it's your job to figure out how to turn that into a while loop.

How to create multiple page app using react

Preface

This answer uses the dynamic routing approach embraced in react-router v4+. Other answers may reference the previously-used "static routing" approach that has been abandoned by react-router.

Solution

react-router is a great solution. You create your pages as Components and the router swaps out the pages according to the current URL. In other words, it replaces your original page with your new page dynamically instead of asking the server for a new page.

For web apps I recommend you read these two things first:

Summary of the general approach:

1 - Add react-router-dom to your project:

Yarn

yarn add react-router-dom

or NPM

npm install react-router-dom

2 - Update your index.js file to something like:

import { BrowserRouter } from 'react-router-dom';

ReactDOM.render((
  <BrowserRouter>
    <App /> {/* The various pages will be displayed by the `Main` component. */}
  </BrowserRouter>
  ), document.getElementById('root')
);

3 - Create a Main component that will show your pages according to the current URL:

import React from 'react';
import { Switch, Route } from 'react-router-dom';

import Home from '../pages/Home';
import Signup from '../pages/Signup';

const Main = () => {
  return (
    <Switch> {/* The Switch decides which component to show based on the current URL.*/}
      <Route exact path='/' component={Home}></Route>
      <Route exact path='/signup' component={Signup}></Route>
    </Switch>
  );
}

export default Main;

4 - Add the Main component inside of the App.js file:

function App() {
  return (
    <div className="App">
      <Navbar />
      <Main />
    </div>
  );
}

5 - Add Links to your pages.

(You must use Link from react-router-dom instead of just a plain old <a> in order for the router to work properly.)

import { Link } from "react-router-dom";
...
<Link to="/signup">
  <button variant="outlined">
    Sign up
  </button>
</Link>

Xcode doesn't see my iOS device but iTunes does

Xcode 6.3 didn't see my iPhone running iOS 8.3 even after a computer restart. I then restarted my iPhone and everything worked again. Love buggy software!

How do I pipe a subprocess call to a text file?

The options for popen can be used in call

args, 
bufsize=0, 
executable=None, 
stdin=None, 
stdout=None, 
stderr=None, 
preexec_fn=None, 
close_fds=False, 
shell=False, 
cwd=None, 
env=None, 
universal_newlines=False, 
startupinfo=None, 
creationflags=0

So...

subprocess.call(["/home/myuser/run.sh", "/tmp/ad_xml",  "/tmp/video_xml"], stdout=myoutput)

Then you can do what you want with myoutput (which would need to be a file btw).

Also, you can do something closer to a piped output like this.

dmesg | grep hda

would be:

p1 = Popen(["dmesg"], stdout=PIPE)
p2 = Popen(["grep", "hda"], stdin=p1.stdout, stdout=PIPE)
output = p2.communicate()[0]

There's plenty of lovely, useful info on the python manual page.

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

please try these

<form action="Delegate_update.php" method="post">
Name
<input type="text" name= "Name" value= "<?php echo $row['Name']; ?> "size=10>
Username
<input type="text" name= "User_name" value= "<?php echo $row['User_name']; ?> "size=10>
Password
<input type="text" name= "User_password" value= "<?php echo $row['User_password']; ?>" size=17>
<input type="submit" name= "submit" value="Update">
</form>

Is it possible to program iPhone in C++

Having some experience of this, you can indeed use C++ code for your "core" code, but you have to use objective-C for anything iPhone specific.

Don't try to force Objective-C to act like C++. At first it will seem to you this is possible, but the resulting code really won't work well with Cocoa, and you will get very confused as to what is going on. Take the time to learn properly, without any C++ around, how to build GUIs and iPhone applications, then link in your C++ base.

How to verify a Text present in the loaded page through WebDriver

Driver.getPageSource() is a bad way to verify text present. Suppose you say, driver.getPageSource().contains("input"); That doesn't verify "input" is present on the screen, only that "input" is present in the html, like an input tag.

I usually verify text on an element by using xpath:

boolean textFound = false;  
try {
    driver.findElement(By.xpath("//*[contains(text(),'someText')]"));
    textFound = true;
} catch (Exception e) {
    textFound = false;
}

If you want an exact text match, just remove the contains function:

driver.findElement(By.xpath("//*[text()='someText']));

how can select from drop down menu and call javascript function

<script type="text/javascript">
function report(func)
{
    func();
}

function daily()
{
    alert('daily');
}

function monthly()
{
    alert('monthly');
}
</script>

How to run jenkins as a different user

On Mac OS X, the way I enabled Jenkins to pull from my (private) Github repo is:

First, ensure that your user owns the Jenkins directory

sudo chown -R me:me /Users/Shared/Jenkins

Then edit the LaunchDaemon plist for Jenkins (at /Library/LaunchDaemons/org.jenkins-ci.plist) so that your user is the GroupName and the UserName:

    <key>GroupName</key>
    <string>me</string>
...
    <key>UserName</key>
    <string>me</string>

Then reload Jenkins:

sudo launchctl unload -w /Library/LaunchDaemons/org.jenkins-ci.plist
sudo launchctl load -w /Library/LaunchDaemons/org.jenkins-ci.plist

Then Jenkins, since it's running as you, has access to your ~/.ssh directory which has your keys.

Launching Google Maps Directions via an intent on Android

Using the latest cross-platform Google Maps URLs: Even if google maps app is missing it will open in browser

Example https://www.google.com/maps/dir/?api=1&origin=81.23444,67.0000&destination=80.252059,13.060604

Uri.Builder builder = new Uri.Builder();
builder.scheme("https")
    .authority("www.google.com")
    .appendPath("maps")
    .appendPath("dir")
    .appendPath("")
    .appendQueryParameter("api", "1")
    .appendQueryParameter("destination", 80.00023 + "," + 13.0783);
String url = builder.build().toString();
Log.d("Directions", url);
Intent i = new Intent(Intent.ACTION_VIEW);
i.setData(Uri.parse(url));
startActivity(i);

Using ng-click vs bind within link function of Angular Directive

In this case, no need for a directive. This does the job :

<button ng-click="count = count + 1" ng-init="count=0">
  Increment
</button>
<span>
  count: {{count}}
</span>

Source: https://docs.angularjs.org/api/ng/directive/ngClick

How to kill all processes matching a name?

From man 1 pkill

-f     The pattern is normally only matched against the process name.
       When -f is set, the full command line is used.

Which means, for example, if we see these lines in ps aux:

apache   24268  0.0  2.6 388152 27116 ?        S    Jun13   0:10 /usr/sbin/httpd
apache   24272  0.0  2.6 387944 27104 ?        S    Jun13   0:09 /usr/sbin/httpd
apache   24319  0.0  2.6 387884 27316 ?        S    Jun15   0:04 /usr/sbin/httpd

We can kill them all using the pkill -f option:

pkill -f httpd

How to make div same height as parent (displayed as table-cell)

Another option is to set your child div to display: inline-block;

.content {
    display: inline-block;
    height: 100%;
    width: 100%;
    background-color: blue;
}

_x000D_
_x000D_
.container {_x000D_
  display: table;_x000D_
}_x000D_
.child {_x000D_
  width: 30px;_x000D_
  background-color: red;_x000D_
  display: table-cell;_x000D_
  vertical-align: top;_x000D_
}_x000D_
.content {_x000D_
  display: inline-block;_x000D_
  height: 100%;_x000D_
  width: 100%;_x000D_
  background-color: blue;_x000D_
}
_x000D_
<div class="container">_x000D_
  <div class="child">_x000D_
    a_x000D_
    <br />a_x000D_
    <br />a_x000D_
  </div>_x000D_
  <div class="child">_x000D_
    a_x000D_
    <br />a_x000D_
    <br />a_x000D_
    <br />a_x000D_
    <br />a_x000D_
    <br />a_x000D_
    <br />a_x000D_
  </div>_x000D_
  <div class="child">_x000D_
    <div class="content">_x000D_
      a_x000D_
      <br />a_x000D_
      <br />a_x000D_
    </div>_x000D_
  </div>_x000D_
</div>
_x000D_
_x000D_
_x000D_


JSFiddle Demo

javascript functions to show and hide divs

You can zip the two with something like this [like jQuery does]:

function toggleMyDiv() {
 if (document.getElementById("myDiv").style.display=="block"){
  document.getElementById("myDiv").style.display="none"
  }
 else{
  document.getElementById("myDiv").style.display="block";
 }
}

..and use the same function in the two buttons - or generally in the page for both functions.

variable is not declared it may be inaccessible due to its protection level

I have suffered a similar problem, with a Sub not accessible in runtime, but absolutely legal in editor. It was solved by changing destination Framework from 4.5.1 to 4.5. It seems that my IIS only had 4.5 version.

:)

Using Mockito, how do I verify a method was a called with a certain argument?

Building off of Mamboking's answer:

ContractsDao mock_contractsDao = mock(ContractsDao.class);
when(mock_contractsDao.save(anyString())).thenReturn("Some result");

m_orderSvc.m_contractsDao = mock_contractsDao;
m_prog = new ProcessOrdersWorker(m_orderSvc, m_opportunitySvc, m_myprojectOrgSvc);
m_prog.work(); 

Addressing your request to verify whether the argument contains a certain value, I could assume you mean that the argument is a String and you want to test whether the String argument contains a substring. For this you could do:

ArgumentCaptor<String> savedCaptor = ArgumentCaptor.forClass(String.class);
verify(mock_contractsDao).save(savedCaptor.capture());
assertTrue(savedCaptor.getValue().contains("substring I want to find");

If that assumption was wrong, and the argument to save() is a collection of some kind, it would be only slightly different:

ArgumentCaptor<Collection<MyType>> savedCaptor = ArgumentCaptor.forClass(Collection.class);
verify(mock_contractsDao).save(savedCaptor.capture());
assertTrue(savedCaptor.getValue().contains(someMyTypeElementToFindInCollection);

You might also check into ArgumentMatchers, if you know how to use Hamcrest matchers.

How to hide the soft keyboard from inside a fragment?

Exception for DialogFragment though, focus of the embedded Dialog must be hidden, instead only the first EditText within the embedded Dialog

this.getDialog().getWindow().setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_STATE_HIDDEN);

Hiding the R code in Rmarkdown/knit and just showing the results

Sure, just do

```{r someVar, echo=FALSE}
someVariable
```

to show some (previously computed) variable someVariable. Or run code that prints etc pp.

So for plotting, I have eg

### Impact of choice of ....
```{r somePlot, echo=FALSE}
plotResults(Res, Grid, "some text", "some more text")
```

where the plotting function plotResults is from a local package.

Select2 doesn't work when embedded in a bootstrap modal

I solved this generally in my project by overloading the select2-function. Now it will check if there is no dropdownParent and if the function is called on an element that has a parent of the type div.modal. If so, it will add that modal as the parent for the dropdown.

This way, you don't have to specify it every time you create a select2-input-box.

(function(){
    var oldSelect2 = jQuery.fn.select2;
    jQuery.fn.select2 = function() {
        const modalParent = jQuery(this).parents('div.modal').first();
        if (arguments.length === 0 && modalParent.length > 0) {
            arguments = [{dropdownParent: modalParent}];
        } else if (arguments.length === 1
                    && typeof arguments[0] === 'object'
                    && typeof arguments[0].dropdownParent === 'undefined'
                    && modalParent.length > 0) {
            arguments[0].dropdownParent = modalParent;
        }
        return oldSelect2.apply(this,arguments);
    };
    // Copy all properties of the old function to the new
    for (var key in oldSelect2) {
        jQuery.fn.select2[key] = oldSelect2[key];
    }
})();

What is the maximum length of a String in PHP?

The maximum length of a string variable is only 2GiB - (2^(32-1) bits). Variables can be addressed on a character (8 bits/1 byte) basis and the addressing is done by signed integers which is why the limit is what it is. Arrays can contain multiple variables that each follow the previous restriction but can have a total cumulative size up to memory_limit of which a string variable is also subject to.

How to read a local text file?

After the introduction of fetch api in javascript, reading file contents could not be simpler.

reading a text file

fetch('file.txt')
  .then(response => response.text())
  .then(text => console.log(text))
  // outputs the content of the text file

reading a json file

fetch('file.json')
  .then(response => response.json())
  .then(jsonResponse => console.log(jsonResponse))     
   // outputs a javascript object from the parsed json

Update 30/07/2018 (disclaimer):

This technique works fine in Firefox, but it seems like Chrome's fetch implementation does not support file:/// URL scheme at the date of writing this update (tested in Chrome 68).

Update-2 (disclaimer):

This technique does not work with Firefox above version 68 (Jul 9, 2019) for the same (security) reason as Chrome: CORS request not HTTP. See https://developer.mozilla.org/en-US/docs/Web/HTTP/CORS/Errors/CORSRequestNotHttp.

Algorithm to return all combinations of k elements from n

Clojure version:

(defn comb [k l]
  (if (= 1 k) (map vector l)
      (apply concat
             (map-indexed
              #(map (fn [x] (conj x %2))
                    (comb (dec k) (drop (inc %1) l)))
              l))))

SQLiteDatabase.query method

db.query(
        TABLE_NAME,
        new String[] { TABLE_ROW_ID, TABLE_ROW_ONE, TABLE_ROW_TWO },
        TABLE_ROW_ID + "=" + rowID,
        null, null, null, null, null
);

TABLE_ROW_ID + "=" + rowID, here = is the where clause. To select all values you will have to give all column names:

or you can use a raw query like this 
db.rawQuery("SELECT * FROM permissions_table WHERE name = 'Comics' ", null);

and here is a good tutorial for database.

Passing arguments to JavaScript function from code-behind

Some other things I found out:

You can't directly pass in an array like:

this.Page.ClientScript.RegisterClientScriptBlock(this.GetType(), "xx",   
"<script>test("+x+","+y+");</script>");

because that calls the ToString() methods of x and y, which returns "System.Int32[]", and obviously Javascript can't use that. I had to pass in the arrays as strings, like "[1,2,3,4,5]", so I wrote a helper method to do the conversion.

Also, there is a difference between this.Page.ClientScript.RegisterStartupScript() and this.Page.ClientScript.RegisterClientScriptBlock() - the former places the script at the bottom of the page, which I need in order to be able to access the controls (like with document.getElementByID). RegisterClientScriptBlock() is executed before the tags are rendered, so I actually get a Javascript error if I use that method.

http://www.wrox.com/WileyCDA/Section/Manipulating-ASP-NET-Pages-and-Server-Controls-with-JavaScript.id-310803.html covers the difference between the two pretty well.

Here's the complete example I came up with:

// code behind
protected void Button1_Click(object sender, EventArgs e)
{
    int[] x = new int[] { 1, 2, 3, 4, 5 };
    int[] y = new int[] { 1, 2, 3, 4, 5 };

    string xStr = getArrayString(x); // converts {1,2,3,4,5} to [1,2,3,4,5]
    string yStr = getArrayString(y);

    string script = String.Format("test({0},{1})", xStr, yStr);
    this.Page.ClientScript.RegisterStartupScript(this.GetType(),
    "testFunction", script, true);
    //this.Page.ClientScript.RegisterClientScriptBlock(this.GetType(),
    //"testFunction", script, true); // different result
}
private string getArrayString(int[] array)
{
    StringBuilder sb = new StringBuilder();
    for (int i = 0; i < array.Length; i++)
    {
        sb.Append(array[i] + ",");
    }
    string arrayStr = string.Format("[{0}]", sb.ToString().TrimEnd(','));
    return arrayStr;
}

//aspx page
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title>Untitled Page</title>
    <script type="text/javascript">
    function test(x, y)
    {
        var text1 = document.getElementById("text1")
        for(var i = 0; i<x.length; i++)
        {
            text1.innerText += x[i]; // prints 12345
        }
        text1.innerText += "\ny: " + y; // prints y: 1,2,3,4,5

    }

    </script>
</head>
<body>
    <form id="form1" runat="server">
    <div>
        <asp:Button ID="Button1" runat="server" Text="Button"
         onclick="Button1_Click" />
    </div>
    <div id ="text1"> 
    </div>
    </form>
</body>
</html>

Regular expression - starting and ending with a letter, accepting only letters, numbers and _

seeing how the rules are fairly complicated, I'd suggest the following:

/^[a-z](\w*)[a-z0-9]$/i

match the whole string and capture intermediate characters. Then either with the string functions or the following regex:

/__/

check if the captured part has two underscores in a row. For example in Python it would look like this:

>>> import re
>>> def valid(s):
    match = re.match(r'^[a-z](\w*)[a-z0-9]$', s, re.I)
    if match is not None:
        return match.group(1).count('__') == 0
    return False

How can I programmatically generate keypress events in C#?

I've not used it, but SendKeys may do what you want.

Use SendKeys to send keystrokes and keystroke combinations to the active application. This class cannot be instantiated. To send a keystroke to a class and immediately continue with the flow of your program, use Send. To wait for any processes started by the keystroke, use SendWait.

System.Windows.Forms.SendKeys.Send("A");
System.Windows.Forms.SendKeys.Send("{ENTER}");

Microsoft has some more usage examples here.

Test iOS app on device without apple developer program or jailbreak

I never tried, but doing a google search, Jailcoder looks like a solution. The problem is the device need to be jailbroken. If anyone try this, please comment and let us know how it worked.

Adding new column to existing DataFrame in Python pandas

Before assigning a new column, if you have indexed data, you need to sort the index. At least in my case I had to:

data.set_index(['index_column'], inplace=True)
"if index is unsorted, assignment of a new column will fail"        
data.sort_index(inplace = True)
data.loc['index_value1', 'column_y'] = np.random.randn(data.loc['index_value1', 'column_x'].shape[0])

How to use Redirect in the new react-router-dom of Reactjs

Alternatively, you can use React conditional rendering.

import { Redirect } from "react-router";
import React, { Component } from 'react';

class UserSignup extends Component {
  constructor(props) {
    super(props);
    this.state = {
      redirect: false
    }
  }
render() {
 <React.Fragment>
   { this.state.redirect && <Redirect to="/signin" /> }   // you will be redirected to signin route
}
</React.Fragment>
}

Switching to landscape mode in Android Emulator

In my windows-8 laptop, ctrl + fn + F11 works.

How can I scale an image in a CSS sprite

transform: scale(); will make original element preserve its size.

I found the best option is to use vw. It's working like a charm:

https://jsfiddle.net/tomekmularczyk/6ebv9Lxw/1/

_x000D_
_x000D_
#div1,_x000D_
#div2,_x000D_
#div3 {_x000D_
  background:url('//www.google.pl/images/branding/googlelogo/2x/googlelogo_color_272x92dp.png') no-repeat;_x000D_
  background-size: 50vw;   _x000D_
  border: 1px solid black;_x000D_
  margin-bottom: 40px;_x000D_
}_x000D_
_x000D_
#div1 {_x000D_
  background-position: 0 0;_x000D_
  width: 12.5vw;_x000D_
  height: 13vw;_x000D_
}_x000D_
#div2 {_x000D_
  background-position: -13vw -4vw;_x000D_
  width: 17.5vw;_x000D_
  height: 9vw;_x000D_
  transform: scale(1.8);_x000D_
}_x000D_
#div3 {_x000D_
  background-position: -30.5vw 0;_x000D_
  width: 19.5vw;_x000D_
  height: 17vw;_x000D_
}
_x000D_
<div id="div1">_x000D_
  </div>_x000D_
  <div id="div2">_x000D_
  </div>_x000D_
  <div id="div3">_x000D_
  </div>
_x000D_
_x000D_
_x000D_

How to remove duplicate values from an array in PHP

We can create such type of array to use this last value will be updated into column or key value and we will get unique value from the array...

$array = array (1,3,4,2,1,7,4,9,7,5,9);
    $data=array();
    foreach($array as $value ){

        $data[$value]= $value;

    }

    array_keys($data);
    OR
    array_values($data);

Launch Bootstrap Modal on page load

Update 2020 - Bootstrap 5

Building on the excellent responses from previous answers, in Bootstrap 5 with no jQuery, this has worked;

document.querySelector('[data-target="#exampleModal"]').click();

Full snippet:

_x000D_
_x000D_
window.onload = () => {
  document.querySelector('[data-target="#exampleModal"]').click();
}
_x000D_
<script src="https://stackpath.bootstrapcdn.com/bootstrap/5.0.0-alpha1/js/bootstrap.min.js"></script>
<script src="https://cdn.jsdelivr.net/npm/[email protected]/dist/umd/popper.min.js"></script>
<link href="https://stackpath.bootstrapcdn.com/bootstrap/5.0.0-alpha1/css/bootstrap.min.css" rel="stylesheet" />


<div class="container py-3">

  <!-- Button trigger modal -->
  <button type="button" class="btn btn-primary" data-toggle="modal" data-target="#exampleModal">
    Launch demo modal
  </button>

  <!-- Modal -->
  <div class="modal fade" id="exampleModal" tabindex="-1" aria-labelledby="exampleModalLabel" aria-hidden="true">
    <div class="modal-dialog">
      <div class="modal-content">
        <div class="modal-header">
          <h5 class="modal-title" id="exampleModalLabel">Modal title</h5>
          <button type="button" class="close" data-dismiss="modal" aria-label="Close">
            <span aria-hidden="true">&times;</span>
          </button>
        </div>
        <div class="modal-body">
          ...
        </div>
        <div class="modal-footer">
          <button type="button" class="btn btn-secondary" data-dismiss="modal">Close</button>
          <button type="button" class="btn btn-primary">Save changes</button>
        </div>
      </div>
    </div>
  </div>

</div>
_x000D_
_x000D_
_x000D_

Port 80 is being used by SYSTEM (PID 4), what is that?

For me it worked after stopping Web Deployment Agent Service.

How to convert CharSequence to String?

There is a subtle issue here that is a bit of a gotcha.

The toString() method has a base implementation in Object. CharSequence is an interface; and although the toString() method appears as part of that interface, there is nothing at compile-time that will force you to override it and honor the additional constraints that the CharSequence toString() method's javadoc puts on the toString() method; ie that it should return a string containing the characters in the order returned by charAt().

Your IDE won't even help you out by reminding that you that you probably should override toString(). For example, in intellij, this is what you'll see if you create a new CharSequence implementation: http://puu.sh/2w1RJ. Note the absence of toString().

If you rely on toString() on an arbitrary CharSequence, it should work provided the CharSequence implementer did their job properly. But if you want to avoid any uncertainty altogether, you should use a StringBuilder and append(), like so:

final StringBuilder sb = new StringBuilder(charSequence.length());
sb.append(charSequence);
return sb.toString();

how to fetch array keys with jQuery?

Don't Reinvent the Wheel, Use Underscore

I know the OP specifically mentioned jQuery but I wanted to put an answer here to introduce people to the helpful Underscore library if they are not aware of it already.

By leveraging the keys method in the Underscore library, you can simply do the following:

_.keys(foo)  #=> ["alfa", "beta"]

Plus, there's a plethora of other useful functions that are worth perusing.

How do you write a migration to rename an ActiveRecord model and its table in Rails?

Here's an example:

class RenameOldTableToNewTable < ActiveRecord::Migration
  def self.up
    rename_table :old_table_name, :new_table_name
  end

  def self.down
    rename_table :new_table_name, :old_table_name
  end
end

I had to go and rename the model declaration file manually.

Edit:

In Rails 3.1 & 4, ActiveRecord::Migration::CommandRecorder knows how to reverse rename_table migrations, so you can do this:

class RenameOldTableToNewTable < ActiveRecord::Migration
  def change
    rename_table :old_table_name, :new_table_name
  end 
end

(You still have to go through and manually rename your files.)

Adding POST parameters before submit

you can do this without jQuery:

    var form=document.getElementById('form-id');//retrieve the form as a DOM element

    var input = document.createElement('input');//prepare a new input DOM element
    input.setAttribute('name', inputName);//set the param name
    input.setAttribute('value', inputValue);//set the value
    input.setAttribute('type', inputType)//set the type, like "hidden" or other

    form.appendChild(input);//append the input to the form

    form.submit();//send with added input

Installing Bower on Ubuntu

Ubuntu 16.04 and later

Bower is a package manager primarily for (but not limited to) front-end web development. In Ubuntu 16.04 and later Bower package manager can be quickly and easily installed from the Ubuntu Software app. Open Ubuntu Software, search for "bower" and click the Install button to install it. In all currently supported versions of Ubuntu open the terminal and type:

sudo snap install bower --classic

enter image description here

Convert NSNumber to int in Objective-C

You should stick to the NSInteger data types when possible. So you'd create the number like that:

NSInteger myValue = 1;
NSNumber *number = [NSNumber numberWithInteger: myValue];

Decoding works with the integerValue method then:

NSInteger value = [number integerValue];

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.

SQL Server query to find all current database names

For people where "sys.databases" does not work, You can use this aswell;

SELECT DISTINCT TABLE_SCHEMA from INFORMATION_SCHEMA.COLUMNS

How do I change the default index page in Apache?

You can also set DirectoryIndex in apache's httpd.conf file.

CentOS keeps this file in /etc/httpd/conf/httpd.conf Debian: /etc/apache2/apache2.conf

Open the file in your text editor and find the line starting with DirectoryIndex

To load landing.html as a default (but index.html if that's not found) change this line to read:

DirectoryIndex  landing.html index.html

Could not read JSON: Can not deserialize instance of hello.Country[] out of START_OBJECT token

If you want to avoid using an extra Class and List<Object> genomes you could simply use a Map.

The data structure translates into Map<String, List<Country>>

String resourceEndpoint = "http://api.geonames.org/countryInfoJSON?username=volodiaL";

Map<String, List<Country>> geonames = restTemplate.getForObject(resourceEndpoint, Map.class);

List<Country> countries = geonames.get("geonames");

How to create timer events using C++ 11?

If you are on Windows, you can use the CreateThreadpoolTimer function to schedule a callback without needing to worry about thread management and without blocking the current thread.

template<typename T>
static void __stdcall timer_fired(PTP_CALLBACK_INSTANCE, PVOID context, PTP_TIMER timer)
{
    CloseThreadpoolTimer(timer);
    std::unique_ptr<T> callable(reinterpret_cast<T*>(context));
    (*callable)();
}

template <typename T>
void call_after(T callable, long long delayInMs)
{
    auto state = std::make_unique<T>(std::move(callable));
    auto timer = CreateThreadpoolTimer(timer_fired<T>, state.get(), nullptr);
    if (!timer)
    {
        throw std::runtime_error("Timer");
    }

    ULARGE_INTEGER due;
    due.QuadPart = static_cast<ULONGLONG>(-(delayInMs * 10000LL));

    FILETIME ft;
    ft.dwHighDateTime = due.HighPart;
    ft.dwLowDateTime = due.LowPart;

    SetThreadpoolTimer(timer, &ft, 0 /*msPeriod*/, 0 /*msWindowLength*/);
    state.release();
}

int main()
{
    auto callback = []
    {
        std::cout << "in callback\n";
    };

    call_after(callback, 1000);
    std::cin.get();
}

correct way to define class variables in Python

Neither way is necessarily correct or incorrect, they are just two different kinds of class elements:

  • Elements outside the __init__ method are static elements; they belong to the class.
  • Elements inside the __init__ method are elements of the object (self); they don't belong to the class.

You'll see it more clearly with some code:

class MyClass:
    static_elem = 123

    def __init__(self):
        self.object_elem = 456

c1 = MyClass()
c2 = MyClass()

# Initial values of both elements
>>> print c1.static_elem, c1.object_elem 
123 456
>>> print c2.static_elem, c2.object_elem
123 456

# Nothing new so far ...

# Let's try changing the static element
MyClass.static_elem = 999

>>> print c1.static_elem, c1.object_elem
999 456
>>> print c2.static_elem, c2.object_elem
999 456

# Now, let's try changing the object element
c1.object_elem = 888

>>> print c1.static_elem, c1.object_elem
999 888
>>> print c2.static_elem, c2.object_elem
999 456

As you can see, when we changed the class element, it changed for both objects. But, when we changed the object element, the other object remained unchanged.

How to view file diff in git before commit

git diff HEAD file

will show you changes you added to your worktree from the last commit. All the changes (staged or not staged) will be shown.

jQuery: get parent, parent id?

$(this).parent().parent().attr('id');

Is how you would get the id of the parent's parent.

EDIT:

$(this).closest('ul').attr('id');

Is a more foolproof solution for your case.

How do I create a file at a specific path?

I recommend using the os module to avoid trouble in cross-platform. (windows,linux,mac)

Cause if the directory doesn't exists, it will return an exception.

import os

filepath = os.path.join('c:/your/full/path', 'filename')
if not os.path.exists('c:/your/full/path'):
    os.makedirs('c:/your/full/path')
f = open(filepath, "a")

If this will be a function for a system or something, you can improve it by adding try/except for error control.

Django - Reverse for '' not found. '' is not a valid view function or pattern name

The common error that I have find is when you forget to define your url in yourapp/urls.py

we don't want any suggetion!! solution plz..

Run batch file from Java code

try following

try {
            String[] command = {"cmd.exe", "/C", "Start", "D:\\test.bat"};
            Process p =  Runtime.getRuntime().exec(command);           
        } catch (IOException ex) {
        }

nodemon not found in npm

You can always reinstall Node.js. When I had this problem, I couldn't fix it, but all I did was update the current version of Node. You can update it with this link: https://nodejs.org/en/download/

Git undo changes in some files

Yes;

git commit FILE

will commit just FILE. Then you can use

git reset --hard

to undo local changes in other files.

There may be other ways too that I don't know about...

edit: or, as NicDumZ said, git-checkout just the files you want to undo the changes on (the best solution depends on wether there are more files to commit or more files to undo :-)

Automatically resize jQuery UI dialog to the width of the content loaded by ajax

I had a similar problem.

Setting width to "auto" worked fine for me but when the dialog contained a lot of text it made it span the full width of the page, ignoring the maxWidth setting.

Setting maxWidth on create works fine though:

$( ".selector" ).dialog({
  width: "auto",
  // maxWidth: 660, // This won't work
  create: function( event, ui ) {
    // Set maxWidth
    $(this).css("maxWidth", "660px");
  }
});

How to replicate vector in c?

Vector and list aren't conceptually tied to C++. Similar structures can be implemented in C, just the syntax (and error handling) would look different. For example LodePNG implements a dynamic array with functionality very similar to that of std::vector. A sample usage looks like:

uivector v = {};
uivector_push_back(&v, 1);
uivector_push_back(&v, 42);
for(size_t i = 0; i < v.size; ++i)
    printf("%d\n", v.data[i]);
uivector_cleanup(&v);

As can be seen the usage is somewhat verbose and the code needs to be duplicated to support different types.

nothings/stb gives a simpler implementation that works with any types, but compiles only in C:

double *v = 0;
sb_push(v, 1.0);
sb_push(v, 42.0);
for(int i = 0; i < sb_count(v); ++i)
    printf("%g\n", v[i]);
sb_free(v);

A lot of C code, however, resorts to managing the memory directly with realloc:

void* newMem = realloc(oldMem, newSize);
if(!newMem) {
    // handle error
}
oldMem = newMem;

Note that realloc returns null in case of failure, yet the old memory is still valid. In such situation this common (and incorrect) usage leaks memory:

oldMem = realloc(oldMem, newSize);
if(!oldMem) {
    // handle error
}

Compared to std::vector and the C equivalents from above, the simple realloc method does not provide O(1) amortized guarantee, even though realloc may sometimes be more efficient if it happens to avoid moving the memory around.

Apache won't run in xampp

Take a look at this site:

http://www.lukebrowning.com/blog/nt-kernel-system-using-port-80/

In my case, it was the SQL Server Reporting Service, but others have seen IIS or the Web Deployment Agent Service.

Open a cmd window and run services.msc, find the service, and stop it. Then try to start Apache. If it works, disable the other service.

Using multiple .cpp files in c++ program?

You can simply place a forward declaration of your second() function in your main.cpp above main(). If your second.cpp has more than one function and you want all of it in main(), put all the forward declarations of your functions in second.cpp into a header file and #include it in main.cpp.

Like this-

Second.h:

void second();
int third();
double fourth();

main.cpp:

#include <iostream>
#include "second.h"
int main()
{
    //.....
    return 0;
}

second.cpp:

void second()
{
    //...
}

int third()
{ 
    //...
    return foo;
}

double fourth()
{ 
    //...
    return f;
}

Note that: it is not necessary to #include "second.h" in second.cpp. All your compiler need is forward declarations and your linker will do the job of searching the definitions of those declarations in the other files.

Merging Cells in Excel using C#

Using the Interop you get a range of cells and call the .Merge() method on that range.

eWSheet.Range[eWSheet.Cells[1, 1], eWSheet.Cells[4, 1]].Merge();

How to see which flags -march=native will activate?

It should be (-### is similar to -v):

echo | gcc -### -E - -march=native 

To show the "real" native flags for gcc.

You can make them appear more "clearly" with a command:

gcc -### -E - -march=native 2>&1 | sed -r '/cc1/!d;s/(")|(^.* - )//g'

and you can get rid of flags with -mno-* with:

gcc -### -E - -march=native 2>&1 | sed -r '/cc1/!d;s/(")|(^.* - )|( -mno-[^\ ]+)//g'

Understanding React-Redux and mapStateToProps()

It's a simple concept. Redux creates a ubiquitous state object (a store) from the actions in the reducers. Like a React component, this state doesn't have to be explicitly coded anywhere, but it helps developers to see a default state object in the reducer file to visualise what is happening. You import the reducer in the component to access the file. Then mapStateToProps selects only the key/value pairs in the store that its component needs. Think of it like Redux creating a global version of a React component's

this.state = ({ 
cats = [], 
dogs = []
})

It is impossible to change the structure of the state by using mapStateToProps(). What you are doing is choosing only the store's key/value pairs that the component needs and passing in the values (from a list of key/values in the store) to the props (local keys) in your component. You do this one value at a time in a list. No structure changes can occur in the process.

P.S. The store is local state. Reducers usually also pass state along to the database with Action Creators getting into the mix, but understand this simple concept first for this specific posting.

P.P.S. It is good practice to separate the reducers into separate files for each one and only import the reducer that the component needs.

Git - how delete file from remote repository

Use commands :

git rm /path to file name /

followed by

git commit -m "Your Comment"

git push

your files will get deleted from the repository

How to BULK INSERT a file into a *temporary* table where the filename is a variable?

You could always construct the #temp table in dynamic SQL. For example, right now I guess you have been trying:

CREATE TABLE #tmp(a INT, b INT, c INT);

DECLARE @sql NVARCHAR(1000);

SET @sql = N'BULK INSERT #tmp ...' + @variables;

EXEC master.sys.sp_executesql @sql;

SELECT * FROM #tmp;

This makes it tougher to maintain (readability) but gets by the scoping issue:

DECLARE @sql NVARCHAR(MAX);

SET @sql = N'CREATE TABLE #tmp(a INT, b INT, c INT);

BULK INSERT #tmp ...' + @variables + ';

SELECT * FROM #tmp;';

EXEC master.sys.sp_executesql @sql;

EDIT 2011-01-12

In light of how my almost 2-year old answer was suddenly deemed incomplete and unacceptable, by someone whose answer was also incomplete, how about:

CREATE TABLE #outer(a INT, b INT, c INT);

DECLARE @sql NVARCHAR(MAX);

SET @sql = N'SET NOCOUNT ON; 

CREATE TABLE #inner(a INT, b INT, c INT);

BULK INSERT #inner ...' + @variables + ';

SELECT * FROM #inner;';

INSERT #outer EXEC master.sys.sp_executesql @sql;

Best way to store time (hh:mm) in a database

I would convert them to an integer (HH*3600 + MM*60), and store it that way. Small storage size, and still easy enough to work with.

C# "as" cast vs classic cast

You use the "as" statement to avoid the possibility of an exception, e.g. you can handle the cast failure gracefully via logic. Only use the cast when you are sure that the object is of the desired type. I almost always use the "as" and then check for null.

converting Java bitmap to byte array

CompressFormat is too slow...

Try ByteBuffer.

???Bitmap to byte???

width = bitmap.getWidth();
height = bitmap.getHeight();

int size = bitmap.getRowBytes() * bitmap.getHeight();
ByteBuffer byteBuffer = ByteBuffer.allocate(size);
bitmap.copyPixelsToBuffer(byteBuffer);
byteArray = byteBuffer.array();

???byte to bitmap???

Bitmap.Config configBmp = Bitmap.Config.valueOf(bitmap.getConfig().name());
Bitmap bitmap_tmp = Bitmap.createBitmap(width, height, configBmp);
ByteBuffer buffer = ByteBuffer.wrap(byteArray);
bitmap_tmp.copyPixelsFromBuffer(buffer);

Didn't find class "com.google.firebase.provider.FirebaseInitProvider"?

As mentioned previously, this is a problem with multidex: you should add implementation to your build.gradle and MainApplication.java. But what you add really depends on whether you support AndroidX or not. Here is what you need to solve this problem:

  1. If you support AndroidX

Put these lines of code into your build.gradle (android/app/build.gradle):

defaultConfig {
  applicationId "com.your.application"
  versionCode 1
  versionName "1.0"
  ...
  multiDexEnabled true // <-- THIS LINE
}
...
...
dependencies {
  ...
  implementation "androidx.multidex:multidex:2.0.1" // <-- THIS LINE
  ...
}

Put these lines into your MainApplication.java (android/app/src/main/java/.../MainApplication.java):

package com.your.package;

import androidx.multidex.MultiDexApplication; // <-- THIS LINE
...
...
public class MainApplication extends MultiDexApplication { ... } // <-- THIS LINE
  1. If you don't support AndroidX

Put these lines of code into your build.gradle (android/app/build.gradle):

defaultConfig {
  applicationId "com.your.application"
  versionCode 1
  versionName "1.0"
  ...
  multiDexEnabled true // <-- THIS LINE
}
...
...
dependencies {
  ...
  implementation "com.android.support:multidex:1.0.3" // <-- THIS LINE
  ...
}

Put these lines into your MainApplication.java (android/app/src/main/java/.../MainApplication.java):

package com.your.package;

import android.support.multidex.MultiDex;; // <-- THIS LINE
...
...
public class MainApplication extends MultiDexApplication { ... } // <-- THIS LINE

Getting "TypeError: failed to fetch" when the request hasn't actually failed

The issue could be with the response you are receiving from back-end. If it was working fine on the server then the problem could be with the response headers. Check the Access-Control-Allow-Origin (ACAO) in the response headers. Usually react's fetch API will throw fail to fetch even after receiving response when the response headers' ACAO and the origin of request won't match.

execJs: 'Could not find a JavaScript runtime' but execjs AND therubyracer are in Gemfile

When you create an empty project, this line is commented in Gemfile. Just uncomment it and bundle!

gem 'therubyracer', :platforms => :ruby

How to symbolicate crash log Xcode?

Make sure that your Xcode application name doesn't contain any spaces. This was the reason it didn't work for me. So /Applications/Xcode.app works, while /Applications/Xcode 6.1.1.app doesn't work.

String.Format alternative in C++

You can just concatenate the strings and build a command line.

std::string command = a + ' ' + b + " > " + c;
system(command.c_str());

You don't need any extra libraries for this.

How to serve an image using nodejs

This method works for me, it's not dynamic but straight to the point:

const fs      = require('fs');
const express = require('express');
const app     = express();

app.get( '/logo.gif', function( req, res ) {

  fs.readFile( 'logo.gif', function( err, data ) {

    if ( err ) {

      console.log( err );
      return;
    }

    res.write( data );
    return res.end();
  });

});

app.listen( 80 );

How can I make a thumbnail <img> show a full size image when clicked?

That sort of functionality is going to require some Javascript, but it is probably possible just to use CSS (in browsers other than IE6&7).

Send form data with jquery ajax json

Sending data from formfields back to the server (php) is usualy done by the POST method which can be found back in the superglobal array $_POST inside PHP. There is no need to transform it to JSON before you send it to the server. Little example:

<?php

if($_SERVER['REQUEST_METHOD'] == 'POST')
{
    echo '<pre>';
    print_r($_POST);
}
?>
<form action="" method="post">
<input type="text" name="email" value="[email protected]" />
<button type="submit">Send!</button>

With AJAX you are able to do exactly the same thing, only without page refresh.

RESTful web service - how to authenticate requests from other services?

I would use have an application redirect a user to your site with an application id parameter, once the user approves the request generate a unique token that is used by the other app for authentication. This way the other applications are not handling user credentials and other applications can be added, removed and managed by users. Foursquare and a few other sites authenticate this way and its very easy to implement as the other application.

Ajax passing data to php script

You are sending a POST AJAX request so use $albumname = $_POST['album']; on your server to fetch the value. Also I would recommend you writing the request like this in order to ensure proper encoding:

$.ajax({  
    type: 'POST',  
    url: 'test.php', 
    data: { album: this.title },
    success: function(response) {
        content.html(response);
    }
});

or in its shorter form:

$.post('test.php', { album: this.title }, function() {
    content.html(response);
});

and if you wanted to use a GET request:

$.ajax({  
    type: 'GET',
    url: 'test.php', 
    data: { album: this.title },
    success: function(response) {
        content.html(response);
    }
});

or in its shorter form:

$.get('test.php', { album: this.title }, function() {
    content.html(response);
});

and now on your server you wil be able to use $albumname = $_GET['album'];. Be careful though with AJAX GET requests as they might be cached by some browsers. To avoid caching them you could set the cache: false setting.

Java Regex to Validate Full Name allow only Spaces and Letters

check this out.

String name validation only accept alphabets and spaces
public static boolean validateLetters(String txt) {

    String regx = "^[a-zA-Z\\s]+$";
    Pattern pattern = Pattern.compile(regx,Pattern.CASE_INSENSITIVE);
    Matcher matcher = pattern.matcher(txt);
    return matcher.find();

}

Set value for particular cell in pandas DataFrame with iloc

To modify the value in a cell at the intersection of row "r" (in column "A") and column "C"

  1. retrieve the index of the row "r" in column "A"

        i = df[ df['A']=='r' ].index.values[0]
    
  2. modify the value in the desired column "C"

        df.loc[i,"C"]="newValue"
    

Note: before, be sure to reset the index of rows ...to have a nice index list!

        df=df.reset_index(drop=True)

how to save and read array of array in NSUserdefaults in swift?

The question reads "array of array" but I think most people probably come here just wanting to know how to save an array to UserDefaults. For those people I will add a few common examples.

String array

Save array

let array = ["horse", "cow", "camel", "sheep", "goat"]

let defaults = UserDefaults.standard
defaults.set(array, forKey: "SavedStringArray")

Retrieve array

let defaults = UserDefaults.standard
let myarray = defaults.stringArray(forKey: "SavedStringArray") ?? [String]()

Int array

Save array

let array = [15, 33, 36, 723, 77, 4]

let defaults = UserDefaults.standard
defaults.set(array, forKey: "SavedIntArray")

Retrieve array

let defaults = UserDefaults.standard
let array = defaults.array(forKey: "SavedIntArray")  as? [Int] ?? [Int]()

Bool array

Save array

let array = [true, true, false, true, false]

let defaults = UserDefaults.standard
defaults.set(array, forKey: "SavedBoolArray")

Retrieve array

let defaults = UserDefaults.standard
let array = defaults.array(forKey: "SavedBoolArray")  as? [Bool] ?? [Bool]()

Date array

Save array

let array = [Date(), Date(), Date(), Date()]

let defaults = UserDefaults.standard
defaults.set(array, forKey: "SavedDateArray")

Retrieve array

let defaults = UserDefaults.standard
let array = defaults.array(forKey: "SavedDateArray")  as? [Date] ?? [Date]()

Object array

Custom objects (and consequently arrays of objects) take a little more work to save to UserDefaults. See the following links for how to do it.

Notes

  • The nil coalescing operator (??) allows you to return the saved array or an empty array without crashing. It means that if the object returns nil, then the value following the ?? operator will be used instead.
  • As you can see, the basic setup was the same for Int, Bool, and Date. I also tested it with Double. As far as I know, anything that you can save in a property list will work like this.

What's the better (cleaner) way to ignore output in PowerShell?

I just did some tests of the four options that I know about.

Measure-Command {$(1..1000) | Out-Null}

TotalMilliseconds : 76.211

Measure-Command {[Void]$(1..1000)}

TotalMilliseconds : 0.217

Measure-Command {$(1..1000) > $null}

TotalMilliseconds : 0.2478

Measure-Command {$null = $(1..1000)}

TotalMilliseconds : 0.2122

## Control, times vary from 0.21 to 0.24
Measure-Command {$(1..1000)}

TotalMilliseconds : 0.2141

So I would suggest that you use anything but Out-Null due to overhead. The next important thing, to me, would be readability. I kind of like redirecting to $null and setting equal to $null myself. I use to prefer casting to [Void], but that may not be as understandable when glancing at code or for new users.

I guess I slightly prefer redirecting output to $null.

Do-Something > $null

Edit

After stej's comment again, I decided to do some more tests with pipelines to better isolate the overhead of trashing the output.

Here are some tests with a simple 1000 object pipeline.

## Control Pipeline
Measure-Command {$(1..1000) | ?{$_ -is [int]}}

TotalMilliseconds : 119.3823

## Out-Null
Measure-Command {$(1..1000) | ?{$_ -is [int]} | Out-Null}

TotalMilliseconds : 190.2193

## Redirect to $null
Measure-Command {$(1..1000) | ?{$_ -is [int]} > $null}

TotalMilliseconds : 119.7923

In this case, Out-Null has about a 60% overhead and > $null has about a 0.3% overhead.

Addendum 2017-10-16: I originally overlooked another option with Out-Null, the use of the -inputObject parameter. Using this the overhead seems to disappear, however the syntax is different:

Out-Null -inputObject ($(1..1000) | ?{$_ -is [int]})

And now for some tests with a simple 100 object pipeline.

## Control Pipeline
Measure-Command {$(1..100) | ?{$_ -is [int]}}

TotalMilliseconds : 12.3566

## Out-Null
Measure-Command {$(1..100) | ?{$_ -is [int]} | Out-Null}

TotalMilliseconds : 19.7357

## Redirect to $null
Measure-Command {$(1..1000) | ?{$_ -is [int]} > $null}

TotalMilliseconds : 12.8527

Here again Out-Null has about a 60% overhead. While > $null has an overhead of about 4%. The numbers here varied a bit from test to test (I ran each about 5 times and picked the middle ground). But I think it shows a clear reason to not use Out-Null.

Using CSS :before and :after pseudo-elements with inline CSS?

as mentioned above: its not possible to call a css pseudo-class / -element inline. what i now did, is: give your element a unique identifier, f.ex. an id or a unique class. and write a fitting <style> element

<style>#id29:before { content: "*";}</style>
<article id="id29">
  <!-- something -->
</article>

fugly, but what inline css isnt..?

Find file in directory from command line

If you're looking to do something with a list of files, you can use find combined with the bash $() construct (better than backticks since it's allowed to nest).

for example, say you're at the top level of your project directory and you want a list of all C files starting with "btree". The command:

find . -type f -name 'btree*.c'

will return a list of them. But this doesn't really help with doing something with them.

So, let's further assume you want to search all those file for the string "ERROR" or edit them all. You can execute one of:

grep ERROR $(find . -type f -name 'btree*.c')
vi $(find . -type f -name 'btree*.c')

to do this.

How do I get the real .height() of a overflow: hidden or overflow: scroll div?

Use the .scrollHeight property of the DOM node: $('#your_div')[0].scrollHeight

What is the use of WPFFontCache Service in WPF? WPFFontCache_v0400.exe taking 100 % CPU all the time this exe is running, why?

Use This its is very useful for your solution:

  1. Start > Control Panel > Administrative Tools > Services
  2. Scroll down to 'Windows Presentation Foundation Font Cache 4.0.0.0' and then right click and select properties
  3. In the window then select 'disabled' in the startup type combo

Drawing a line/path on Google Maps

Try this one:
Add itemizedOverlay class:

public class AndroidGoogleMapsActivity extends MapActivity {
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        // Displaying Zooming controls
        MapView mapView = (MapView) findViewById(R.id.mapview);
        mapView.setBuiltInZoomControls(true);


        MapController mc = mapView.getController();
        double lat = Double.parseDouble("48.85827758964043");
        double lon = Double.parseDouble("2.294543981552124");
        GeoPoint geoPoint = new GeoPoint((int)(lat * 1E6), (int)(lon * 1E6));
        mc.animateTo(geoPoint);
        mc.setZoom(15);
        mapView.invalidate(); 


        /**
         * Placing Marker
         * */
        List<Overlay> mapOverlays = mapView.getOverlays();
        Drawable drawable = this.getResources().getDrawable(R.drawable.mark_red);
        AddItemizedOverlay itemizedOverlay = 
             new AddItemizedOverlay(drawable, this);


        OverlayItem overlayitem = new OverlayItem(geoPoint, "Hello", "Sample Overlay item");

        itemizedOverlay.addOverlay(overlayitem);
        mapOverlays.add(itemizedOverlay);

    }

    @Override
    protected boolean isRouteDisplayed() {
        return false;
    }
}

Google Maps: How to create a custom InfoWindow?

You can use code below to remove style default inforwindow. After you can use HTML code for inforwindow:

var inforwindow = "<div style="border-radius: 50%"><img src='URL'></div>"; // show inforwindow image circle
marker.addListener('click', function() {
    $('.gm-style-iw').next().css({'height': '0px'}); //remove arrow bottom inforwindow
    $('.gm-style-iw').prev().html(''); //remove style default inforwindows
});

Convert XML to JSON (and back) using Javascript

Xml-to-json library has methods jsonToXml(json) and xmlToJson(xml).

show and hide divs based on radio button click

Here you can find exactly what you are looking for.

<div align="center">
  <input type="radio" name="name_radio1" id="id_radio1" value="value_radio1">Radio1
  <input type="radio" name="name_radio1" id="id_radio2" value="value_radio2">Radio2
</div>
 <br />
<div align="center" id="id_data" style="border:5">
  <div>this is div 1</div>
  <div>this is div 2</div>
  <div>this is div 3</div>
  <div>this is div 4</div>
</div>
<script src="jquery.js"></script>
<script>
 $(document).ready(function() {
 // show the table as soon as the DOM is ready
 $("#id_data").show();
 // shows the table on clicking the noted link
  $("#id_radio1").click(function() {
   $("#id_data").show("slow");
  });
 // hides the table on clicking the noted link
   $("#id_radio2").click(function() {
   $("#id_data").hide("fast");
   });
 });

  $(document).ready(function(){} – When document load.
  $("#id_data").show(); – shows div which contain id #id_data.
  $("#id_radio1").click(function() – Checks  radio button is clicked containing id #id_radio1.
  $("#id_data").show("slow"); – shows div containing id #id_data.
  $("#id_data").hide("fast"); -hides div when click on radio button containing id #id_data.

Thats it..

http://patelmilap.wordpress.com/2011/02/04/show-hide-div-on-click-using-jquery/

How to run SQL script in MySQL?

I had this error, and tried all the advice i could get to no avail.

Finally, the problem was that my folder had a space in the folder name which appearing as a forward-slash in the folder path, once i found and removed it, it worked fine.

git: 'credential-cache' is not a git command

From a blog I found:

"This [git-credential-cache] doesn’t work for Windows systems as git-credential-cache communicates through a Unix socket."

Git for Windows

Since msysgit has been superseded by Git for Windows, using Git for Windows is now the easiest option. Some versions of the Git for Windows installer (e.g. 2.7.4) have a checkbox during the install to enable the Git Credential Manager. Here is a screenshot:

screenshot of Git For Windows 2.7.4 install wizard

Still using msysgit? For msysgit versions 1.8.1 and above

The wincred helper was added in msysgit 1.8.1. Use it as follows:

git config --global credential.helper wincred

For msysgit versions older than 1.8.1

First, download git-credential-winstore and install it in your git bin directory.

Next, make sure that the directory containing git.cmd is in your Path environment variable. The default directory for this is C:\Program Files (x86)\Git\cmd on a 64-bit system or C:\Program Files\Git\cmd on a 32-bit system. An easy way to test this is to launch a command prompt and type git. If you don't get a list of git commands, then it's not set up correctly.

Finally, launch a command prompt and type:

git config --global credential.helper winstore

Or you can edit your .gitconfig file manually:

[credential]
    helper = winstore

Once you've done this, you can manage your git credentials through Windows Credential Manager which you can pull up via the Windows Control Panel.

TransactionRequiredException Executing an update/delete query

The same exception occurred to me in a somewhat different situation. Since I've been searching here for an answer, maybe it'll help somebody.

I my case the exception has been happening because I called the (properly annotated) @Transactional method from a SERVICE CONSTRUCTOR... Since my idea was simply to make this method run at the start, I annotated it as following, and stopped calling in a wrong way. Exception is gone, and code is better :)

@EventListener(ContextRefreshedEvent.class)
@Transactional
public void methodName() {...}

@Transactional import: import org.springframework.transaction.annotation.Transactional;

Insert data into table with result from another select query

INSERT INTO `test`.`product` ( `p1`, `p2`, `p3`) 
SELECT sum(p1), sum(p2), sum(p3) 
FROM `test`.`product`;

PHP Converting Integer to Date, reverse of strtotime

Can you try this,

echo date("Y-m-d H:i:s", 1388516401);

As noted by theGame,

This means that you pass in a string value for the time, and optionally a value for the current time, which is a UNIX timestamp. The value that is returned is an integer which is a UNIX timestamp.

echo strtotime("2014-01-01 00:00:01");

This will return into the value 1388516401, which is the UNIX timestamp for the date 2014-01-01. This can be confirmed using the date() function as like below:

echo date('Y-m-d', 1198148400); // echos 2014-01-01

Use component from another module

SOLVED HOW TO USE A COMPONENT DECLARED IN A MODULE IN OTHER MODULE.

Based on Royi Namir explanation (Thank you so much). There is a missing part to reuse a component declared in a Module in any other module while lazy loading is used.

1st: Export the component in the module which contains it:

@NgModule({
  declarations: [TaskCardComponent],
  imports: [MdCardModule],
  exports: [TaskCardComponent] <== this line
})
export class TaskModule{}

2nd: In the module where you want to use TaskCardComponent:

import { NgModule } from '@angular/core';
import { CommonModule } from '@angular/common';
import { MdCardModule } from '@angular2-material/card';

@NgModule({
  imports: [
   CommonModule,
   MdCardModule
   ],
  providers: [],
  exports:[ MdCardModule ] <== this line
})
export class TaskModule{}

Like this the second module imports the first module which imports and exports the component.

When we import the module in the second module we need to export it again. Now we can use the first component in the second module.

Git push requires username and password

If you've got 2FA enabled on your Github account, your regular password won't work for this purpose, but you can generate a Personal Access Token and use that in its place instead.

Visit the Settings -> Developer Settings -> Personal Access Tokens page in GitHub (https://github.com/settings/tokens/new), and generate a new Token with all Repo permissions:

generate GitHub personal access token

The page will then display the new token value. Save this value and use it in place of your password when pushing to your repository on GitHub:

> git push origin develop
Username for 'https://github.com': <your username>
Password for 'https://<your username>@github.com': <your personal access token>

Linq order by, group by and order by each group?

I think you want an additional projection that maps each group to a sorted-version of the group:

.Select(group => group.OrderByDescending(student => student.Grade))

It also appears like you might want another flattening operation after that which will give you a sequence of students instead of a sequence of groups:

.SelectMany(group => group)

You can always collapse both into a single SelectMany call that does the projection and flattening together.


EDIT: As Jon Skeet points out, there are certain inefficiencies in the overall query; the information gained from sorting each group is not being used in the ordering of the groups themselves. By moving the sorting of each group to come before the ordering of the groups themselves, the Max query can be dodged into a simpler First query.

Is the buildSessionFactory() Configuration method deprecated in Hibernate

I edited the method created by batbaatar above so it accepts the Configuration object as a parameter:

    public static SessionFactory createSessionFactory(Configuration configuration) {
        serviceRegistry = new StandardServiceRegistryBuilder().applySettings(
                configuration.getProperties()).build();
        factory = configuration.buildSessionFactory(serviceRegistry);
        return factory;
    }

In the main class I did:

    private static SessionFactory factory;
    private static Configuration configuration 
    ...      
    configuration = new Configuration();
    configuration.configure().addAnnotatedClass(Employee.class);
    // Other configurations, then           
    factory = createSessionFactory(configuration);

Use find command but exclude files in two directories

You can try below:

find ./ ! \( -path ./tmp -prune \) ! \( -path ./scripts -prune \) -type f -name '*_peaks.bed'

Disabling swap files creation in vim

For anyone trying to set this for Rails projects, add

set directory=tmp,/tmp

into your

~/.vimrc

So the .swp files will be in their natural location - the tmp directory (per project).

Is there a "do ... while" loop in Ruby?

a = 1
while true
  puts a
  a += 1
  break if a > 10
end

Plotting in a non-blocking way with Matplotlib

The Python package drawnow allows to update a plot in real time in a non blocking way.
It also works with a webcam and OpenCV for example to plot measures for each frame.
See the original post.

How can I find out which server hosts LDAP on my windows domain?

If the machine you are on is part of the AD domain, it should have its name servers set to the AD name servers (or hopefully use a DNS server path that will eventually resolve your AD domains). Using your example of dc=domain,dc=com, if you look up domain.com in the AD name servers it will return a list of the IPs of each AD Controller. Example from my company (w/ the domain name changed, but otherwise it's a real example):

    mokey 0 /home/jj33 > nslookup example.ad
    Server:         172.16.2.10
    Address:        172.16.2.10#53

    Non-authoritative answer:
    Name:   example.ad
    Address: 172.16.6.2
    Name:   example.ad
    Address: 172.16.141.160
    Name:   example.ad
    Address: 172.16.7.9
    Name:   example.ad
    Address: 172.19.1.14
    Name:   example.ad
    Address: 172.19.1.3
    Name:   example.ad
    Address: 172.19.1.11
    Name:   example.ad
    Address: 172.16.3.2

Note I'm actually making the query from a non-AD machine, but our unix name servers know to send queries for our AD domain (example.ad) over to the AD DNS servers.

I'm sure there's a super-slick windowsy way to do this, but I like using the DNS method when I need to find the LDAP servers from a non-windows server.

What is a 'multi-part identifier' and why can't it be bound?

A multipart identifier is any description of a field or table that contains multiple parts - for instance MyTable.SomeRow - if it can't be bound that means there's something wrong with it - either you've got a simple typo, or a confusion between table and column. It can also be caused by using reserved words in your table or field names and not surrounding them with []. It can also be caused by not including all of the required columns in the target table.

Something like redgate sql prompt is brilliant for avoiding having to manually type these (it even auto-completes joins based on foreign keys), but isn't free. SQL server 2008 supports intellisense out of the box, although it isn't quite as complete as the redgate version.

Uncaught SyntaxError: Unexpected token :

When you request your JSON file, server returns JavaScript Content-Type header (text/javascript) instead of JSON (application/json).

According to MooTools docs:

Responses with javascript content-type will be evaluated automatically.

In result MooTools tries to evaluate your JSON as JavaScript, and when you try to evaluate such JSON:

{"votes":47,"totalvotes":90}

as JavaScript, parser treats { and } as a block scope instead of object notation. It is the same as evaluating following "code":

"votes":47,"totalvotes":90

As you can see, : is totally unexpected there.

The solution is to set correct Content-Type header for the JSON file. If you save it with .json extension, your server should do it by itself.

remove double quotes from Json return data using Jquery

What you are doing is making a JSON string in your example. Either don't use the JSON.stringify() or if you ever do have JSON data coming back and you don't want quotations, Simply use JSON.parse() to remove quotations around JSON responses! Don't use regex, there's no need to.

How to Convert string "07:35" (HH:MM) to TimeSpan

Try

var ts = TimeSpan.Parse(stringTime);

With a newer .NET you also have

TimeSpan ts;

if(!TimeSpan.TryParse(stringTime, out ts)){
     // throw exception or whatnot
}
// ts now has a valid format

This is the general idiom for parsing strings in .NET with the first version handling erroneous string by throwing FormatException and the latter letting the Boolean TryParse give you the information directly.

Library not loaded: libmysqlclient.16.dylib error when trying to run 'rails server' on OS X 10.6 with mysql2 gem

I still found that with the solutions above, it didn't work (for example) with the Rails plugin for TextMate. I got a similar error (when retrieving the database schema).

So what did is, open terminal:

cd /usr/local/lib
sudo ln -s ../mysql-5.5.8-osx10.6-x86_64/lib/libmysqlclient.16.dylib .

Replace mysql-5.5.8-osx10.6-x86_64 with your own path (or mysql).

This makes a symbol link to the lib, now rails runs from the command line, as-well as TextMate plugin(s) like ruby-on-rails-tmbundle.

To be clear: this also fixes the error you get when starting rails server.

CSS for grabbing cursors (drag & drop)

CSS3 grab and grabbing are now allowed values for cursor. In order to provide several fallbacks for cross-browser compatibility3 including custom cursor files, a complete solution would look like this:

.draggable {
    cursor: move; /* fallback: no `url()` support or images disabled */
    cursor: url(images/grab.cur); /* fallback: Internet Explorer */
    cursor: -webkit-grab; /* Chrome 1-21, Safari 4+ */
    cursor:    -moz-grab; /* Firefox 1.5-26 */
    cursor:         grab; /* W3C standards syntax, should come least */
}

.draggable:active {
    cursor: url(images/grabbing.cur);
    cursor: -webkit-grabbing;
    cursor:    -moz-grabbing;
    cursor:         grabbing;
}

Update 2019-10-07:

.draggable {
    cursor: move; /* fallback: no `url()` support or images disabled */
    cursor: url(images/grab.cur); /* fallback: Chrome 1-21, Firefox 1.5-26, Safari 4+, IE, Edge 12-14, Android 2.1-4.4.4 */
    cursor: grab; /* W3C standards syntax, all modern browser */
}

.draggable:active {
    cursor: url(images/grabbing.cur);
    cursor: grabbing;
}

Can two applications listen to the same port?

You can make two applications listen for the same port on the same network interface.

There can only be one listening socket for the specified network interface and port, but that socket can be shared between several applications.

If you have a listening socket in an application process and you fork that process, the socket will be inherited, so technically there will be now two processes listening the same port.

ldap query for group members

Active Directory does not store the group membership on user objects. It only stores the Member list on the group. The tools show the group membership on user objects by doing queries for it.

How about:

(&(objectClass=group)(member=cn=my,ou=full,dc=domain))

(You forgot the (& ) bit in your example in the question as well).

How can I get my Android device country code without using GPS?

I have created a utility function (tested once on a device where I was getting an incorrect country code based on locale).

Reference: CountryCodePicker.java

fun getDetectedCountry(context: Context, defaultCountryIsoCode: String): String {

    detectSIMCountry(context)?.let {
        return it
    }

    detectNetworkCountry(context)?.let {
        return it
    }

    detectLocaleCountry(context)?.let {
        return it
    }

    return defaultCountryIsoCode
}

private fun detectSIMCountry(context: Context): String? {
    try {
        val telephonyManager = context.getSystemService(Context.TELEPHONY_SERVICE) as TelephonyManager
        Log.d(TAG, "detectSIMCountry: ${telephonyManager.simCountryIso}")
        return telephonyManager.simCountryIso
    }
    catch (e: Exception) {
        e.printStackTrace()
    }
    return null
}

private fun detectNetworkCountry(context: Context): String? {
    try {
        val telephonyManager = context.getSystemService(Context.TELEPHONY_SERVICE) as TelephonyManager
        Log.d(TAG, "detectNetworkCountry: ${telephonyManager.simCountryIso}")
        return telephonyManager.networkCountryIso
    }
    catch (e: Exception) {
        e.printStackTrace()
    }
    return null
}

private fun detectLocaleCountry(context: Context): String? {
    try {
        val localeCountryISO = context.getResources().getConfiguration().locale.getCountry()
        Log.d(TAG, "detectNetworkCountry: $localeCountryISO")
        return localeCountryISO
    }
    catch (e: Exception) {
        e.printStackTrace()
    }
    return null
}

What is a clearfix?

I tried out the accepted answer but I still had a problem with the content alignment. Adding a ":before" selector as shown below fixed the issue:

// LESS HELPER
.clearfix()
{
    &:after, &:before{
       content: " "; /* Older browser do not support empty content */
       visibility: hidden;
       display: block;
       height: 0;
       clear: both;
    }
}

LESS above will compile to CSS below:

clearfix:after,
clearfix:before {
  content: " ";
  /* Older browser do not support empty content */
  visibility: hidden;
  display: block;
  height: 0;
  clear: both;
}

C++ terminate called without an active exception

As long as your program die, then without detach or join of the thread, this error will occur. Without detaching and joining the thread, you should give endless loop after creating thread.

int main(){

std::thread t(thread,1);

while(1){}

//t.detach();
return 0;}

It is also interesting that, after sleeping or looping, thread can be detach or join. Also with this way you do not get this error.

Below example also shows that, third thread can not done his job before main die. But this error can not happen also, as long as you detach somewhere in the code. Third thread sleep for 8 seconds but main will die in 5 seconds.

void thread(int n) {std::this_thread::sleep_for (std::chrono::seconds(n));}

int main() {
std::cout << "Start main\n";
std::thread t(thread,1);
std::thread t2(thread,3);
std::thread t3(thread,8);
sleep(5);

t.detach();
t2.detach();
t3.detach();
return 0;}

How does strcmp() work?

It uses the byte values of the characters, returning a negative value if the first string appears before the second (ordered by byte values), zero if they are equal, and a positive value if the first appears after the second. Since it operates on bytes, it is not encoding-aware.

For example:

strcmp("abc", "def") < 0
strcmp("abc", "abcd") < 0 // null character is less than 'd'
strcmp("abc", "ABC") > 0 // 'a' > 'A' in ASCII
strcmp("abc", "abc") == 0

More precisely, as described in the strcmp Open Group specification:

The sign of a non-zero return value shall be determined by the sign of the difference between the values of the first pair of bytes (both interpreted as type unsigned char) that differ in the strings being compared.

Note that the return value may not be equal to this difference, but it will carry the same sign.

Python data structure sort list alphabetically

[] denotes a list, () denotes a tuple and {} denotes a dictionary. You should take a look at the official Python tutorial as these are the very basics of programming in Python.

What you have is a list of strings. You can sort it like this:

In [1]: lst = ['Stem', 'constitute', 'Sedge', 'Eflux', 'Whim', 'Intrigue']

In [2]: sorted(lst)
Out[2]: ['Eflux', 'Intrigue', 'Sedge', 'Stem', 'Whim', 'constitute']

As you can see, words that start with an uppercase letter get preference over those starting with a lowercase letter. If you want to sort them independently, do this:

In [4]: sorted(lst, key=str.lower)
Out[4]: ['constitute', 'Eflux', 'Intrigue', 'Sedge', 'Stem', 'Whim']

You can also sort the list in reverse order by doing this:

In [12]: sorted(lst, reverse=True)
Out[12]: ['constitute', 'Whim', 'Stem', 'Sedge', 'Intrigue', 'Eflux']

In [13]: sorted(lst, key=str.lower, reverse=True)
Out[13]: ['Whim', 'Stem', 'Sedge', 'Intrigue', 'Eflux', 'constitute']

Please note: If you work with Python 3, then str is the correct data type for every string that contains human-readable text. However, if you still need to work with Python 2, then you might deal with unicode strings which have the data type unicode in Python 2, and not str. In such a case, if you have a list of unicode strings, you must write key=unicode.lower instead of key=str.lower.

How to plot an array in python?

if you give a 2D array to the plot function of matplotlib it will assume the columns to be lines:

If x and/or y is 2-dimensional, then the corresponding columns will be plotted.

In your case your shape is not accepted (100, 1, 1, 8000). As so you can using numpy squeeze to solve the problem quickly:

np.squeez doc: Remove single-dimensional entries from the shape of an array.

import numpy as np
import matplotlib.pyplot as plt

data = np.random.randint(3, 7, (10, 1, 1, 80))
newdata = np.squeeze(data) # Shape is now: (10, 80)
plt.plot(newdata) # plotting by columns
plt.show()

But notice that 100 sets of 80 000 points is a lot of data for matplotlib. I would recommend that you look for an alternative. The result of the code example (run in Jupyter) is:

Jupyter matplotlib plot