Programs & Examples On #Mysql error 1052

Error 1052 - "Column '%s' in field list is ambiguous". This error appears because there are more than one identically named columns referenced in the query.

How to resolve ambiguous column names when retrieving results?

You can do something like

SELECT news.id as news_id, user.id as user_id ....

And then $row['news_id'] will be the news id and $row['user_id'] will be the user id

MySQL - Selecting data from multiple tables all with same structure but different data

It sounds like you'd be happer with a single table. The five having the same schema, and sometimes needing to be presented as if they came from one table point to putting it all in one table.

Add a new column which can be used to distinguish among the five languages (I'm assuming it's language that is different among the tables since you said it was for localization). Don't worry about having 4.5 million records. Any real database can handle that size no problem. Add the correct indexes, and you'll have no trouble dealing with them as a single table.

1052: Column 'id' in field list is ambiguous

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

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

...or a table alias:

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

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

Why Do These Queries Look Different?

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

What is the official "preferred" way to install pip and virtualenv systemwide?

There is no preferred method - everything depends on your needs. Often you need to have different Python interpreters on the system for whatever reason. In this case you need to install the stuff individually for each interpreter. Apart from that: I prefer installing stuff myself instead of depending of pre-packaged stuff sometimes causing issues - but that's only one possible opionion.

javascript code to check special characters

You can test a string using this regular expression:

function isValid(str){
 return !/[~`!#$%\^&*+=\-\[\]\\';,/{}|\\":<>\?]/g.test(str);
}

Explode string by one or more spaces or tabs

To separate by tabs:

$comp = preg_split("/[\t]/", $var);

To separate by spaces/tabs/newlines:

$comp = preg_split('/\s+/', $var);

To seperate by spaces alone:

$comp = preg_split('/ +/', $var);

CSS no text wrap

Use the css property overflow . For example:

  .item{
    width : 100px;
    overflow:hidden;
  }

The overflow property can have one of many values like ( hidden , scroll , visible ) .. you can als control the overflow in one direction only using overflow-x or overflow-y.

I hope this helps.

SELECT with a Replace()

You have to repeat your expression everywhere you want to use it:

SELECT Replace(Postcode, ' ', '') AS P
FROM Contacts
WHERE Replace(Postcode, ' ', '') LIKE 'NW101%'

or you can make it a subquery

select P
from (
SELECT Replace(Postcode, ' ', '') AS P
FROM Contacts
) t
WHERE P LIKE 'NW101%'

Pretty Printing a pandas dataframe

I used Ofer's answer for a while and found it great in most cases. Unfortunately, due to inconsistencies between pandas's to_csv and prettytable's from_csv, I had to use prettytable in a different way.

One failure case is a dataframe containing commas:

pd.DataFrame({'A': [1, 2], 'B': ['a,', 'b']})

Prettytable raises an error of the form:

Error: Could not determine delimiter

The following function handles this case:

def format_for_print(df):    
    table = PrettyTable([''] + list(df.columns))
    for row in df.itertuples():
        table.add_row(row)
    return str(table)

If you don't care about the index, use:

def format_for_print2(df):    
    table = PrettyTable(list(df.columns))
    for row in df.itertuples():
        table.add_row(row[1:])
    return str(table)

How to delete all files and folders in a directory?

In Windows 7, if you have just created it manually with Windows Explorer, the directory structure is similar to this one:

C:
  \AAA
    \BBB
      \CCC
        \DDD

And running the code suggested in the original question to clean the directory C:\AAA, the line di.Delete(true) always fails with IOException "The directory is not empty" when trying to delete BBB. It is probably because of some kind of delays/caching in Windows Explorer.

The following code works reliably for me:

static void Main(string[] args)
{
    DirectoryInfo di = new DirectoryInfo(@"c:\aaa");
    CleanDirectory(di);
}

private static void CleanDirectory(DirectoryInfo di)
{
    if (di == null)
        return;

    foreach (FileSystemInfo fsEntry in di.GetFileSystemInfos())
    {
        CleanDirectory(fsEntry as DirectoryInfo);
        fsEntry.Delete();
    }
    WaitForDirectoryToBecomeEmpty(di);
}

private static void WaitForDirectoryToBecomeEmpty(DirectoryInfo di)
{
    for (int i = 0; i < 5; i++)
    {
        if (di.GetFileSystemInfos().Length == 0)
            return;
        Console.WriteLine(di.FullName + i);
        Thread.Sleep(50 * i);
    }
}

What's the UIScrollView contentInset property for?

Great question.

Consider the following example (scroller is a UIScrollView):

float offset = 1000;
[super viewDidLoad];
for (int i=0;i<500; i++) {
    UILabel *label = [[[UILabel alloc] initWithFrame:CGRectMake(i * 100, 50, 95, 100)] autorelease];
    [label setText:[NSString stringWithFormat:@"label %d",i]];
    [self.scroller addSubview:label];
    [self.scroller setContentSize:CGSizeMake(self.view.frame.size.width * 2 + offset, 0)];
    [self.scroller setContentInset:UIEdgeInsetsMake(0, -offset, 0, 0)];
}

The insets are the ONLY way to force your scroller to have a "window" on the content where you want it. I'm still messing with this sample code, but the idea is there: use the insets to get a "window" on your UIScrollView.

Javascript (+) sign concatenates instead of giving sum of variables

One place the parentheses suggestion fails is if say both numbers are HTML input variables. Say a and b are variables and one receives their values as follows (I am no HTML expert but my son ran into this and there was no parentheses solution i.e.

  • HTML inputs were intended numerical values for variables a and b, so say the inputs were 2 and 3.
  • Following gave string concatenation outputs: a+b displayed 23; +a+b displayed 23; (a)+(b) displayed 23;
  • From suggestions above we tried successfully : Number(a)+Number(b) displayed 5; parseInt(a) + parseInt(b) displayed 5.

Thanks for the help just an FYI - was very confusing and I his Dad got yelled at 'that is was Blogger.com's fault" - no it's a feature of HTML input default combined with the 'addition' operator, when they occur together, the default left-justified interpretation of all and any input variable is that of a string, and hence the addition operator acts naturally in its dual / parallel role now as a concatenation operator since as you folks explained above it is left-justification type of interpretation protocol in Java and Java script thereafter. Very interesting fact. You folks offered up the solution, I am adding the detail for others who run into this.

Passing additional variables from command line to make

Say you have a makefile like this:

action:
    echo argument is $(argument)

You would then call it make action argument=something

Converting JSON data to Java object

I looked at Google's Gson as a potential JSON plugin. Can anyone offer some form of guidance as to how I can generate Java from this JSON string?

Google Gson supports generics and nested beans. The [] in JSON represents an array and should map to a Java collection such as List or just a plain Java array. The {} in JSON represents an object and should map to a Java Map or just some JavaBean class.

You have a JSON object with several properties of which the groups property represents an array of nested objects of the very same type. This can be parsed with Gson the following way:

package com.stackoverflow.q1688099;

import java.util.List;
import com.google.gson.Gson;

public class Test {

    public static void main(String... args) throws Exception {
        String json = 
            "{"
                + "'title': 'Computing and Information systems',"
                + "'id' : 1,"
                + "'children' : 'true',"
                + "'groups' : [{"
                    + "'title' : 'Level one CIS',"
                    + "'id' : 2,"
                    + "'children' : 'true',"
                    + "'groups' : [{"
                        + "'title' : 'Intro To Computing and Internet',"
                        + "'id' : 3,"
                        + "'children': 'false',"
                        + "'groups':[]"
                    + "}]" 
                + "}]"
            + "}";

        // Now do the magic.
        Data data = new Gson().fromJson(json, Data.class);

        // Show it.
        System.out.println(data);
    }

}

class Data {
    private String title;
    private Long id;
    private Boolean children;
    private List<Data> groups;

    public String getTitle() { return title; }
    public Long getId() { return id; }
    public Boolean getChildren() { return children; }
    public List<Data> getGroups() { return groups; }

    public void setTitle(String title) { this.title = title; }
    public void setId(Long id) { this.id = id; }
    public void setChildren(Boolean children) { this.children = children; }
    public void setGroups(List<Data> groups) { this.groups = groups; }
    
    public String toString() {
        return String.format("title:%s,id:%d,children:%s,groups:%s", title, id, children, groups);
    }
}

Fairly simple, isn't it? Just have a suitable JavaBean and call Gson#fromJson().

See also:

jQuery: how to change title of document during .ready()?

The following should work but it wouldn't be SEO compatible. It's best to put the title in the title tag.

<script type="text/javascript">

    $(document).ready(function() {
        document.title = 'blah';
    });

</script>

How to Detect if I'm Compiling Code with a particular Visual Studio version?

_MSC_VER should be defined to a specific version number. You can either #ifdef on it, or you can use the actual define and do a runtime test. (If for some reason you wanted to run different code based on what compiler it was compiled with? Yeah, probably you were looking for the #ifdef. :))

Trigger event when user scroll to specific element - with jQuery

Fire scroll only once after a successful scroll

The accepted answer worked for me (90%) but I had to tweak it a little to actually fire only once.

$(window).on('scroll',function() {
            var hT = $('#comment-box-section').offset().top,
                hH = $('#comment-box-section').outerHeight(),
                wH = $(window).height(),
                wS = $(this).scrollTop();

            if (wS > ((hT+hH-wH)-500)){
                console.log('comment box section arrived! eh');
                // After Stuff
                $(window).off('scroll');
                doStuff();
            }

        });

Note: By successful scroll I mean when user has scrolled to my element or in other words when my element is in view.

How to scroll to specific item using jQuery?

I did this combination. its work for me. but facing one issue if click move that div size is too large that scenerio scroll not down to this particular div.

 var scrollDownTo =$("#show_question_" + nQueId).position().top;
        console.log(scrollDownTo);
        $('#slider_light_box_container').animate({
            scrollTop: scrollDownTo
            }, 1000, function(){
        });

        }

Failed to find target with hash string 'android-25'

I got similar problem

1: I tried to resolve with the answer which is marked correct above But I was not able to get the system setting which was quit amazing (On MacBook).

Most of the time such errors & issues comes because of replacing your grade file with other grade file ,due which gradel does not sync properly and while building the project issue comes . The issue is bascially related to non syncing for platform tools

Solution a: Go to File and then to Your project strucutre -modules -app-Properties -build tool version -click on options which is required for your project (if required build tool version not there chose any other). This will sync the grade file and now you can go to gradel and change target version and build tool version as per your requirement .you will prompted to download the required platform tool to sync it , now click on install tool version and let project to build

Solution b: Try Anuja Ans if you can get option of system setting and install platform tool.

MySQL compare DATE string with string from DATETIME field

You can cast the DATETIME field into DATE as:

SELECT * FROM `calendar` WHERE CAST(startTime AS DATE) = '2010-04-29'

This is very much efficient.

How do I free my port 80 on localhost Windows?

I faced the same issue and fixed it by making a small change in the httpd.conf file which can be obtained by clicking the config button along with the Apache option.

The change I made was to replace listen 80 with listen 8080.

SQL Last 6 Months

In MySQL

where datetime_column > curdate() - interval (dayofmonth(curdate()) - 1) day - interval 6 month

SQLFiddle demo

In SQL Server

where datetime_column > dateadd(m, -6, getdate() - datepart(d, getdate()) + 1)

SQLFiddle demo

jQuery bind/unbind 'scroll' event on $(window)

try this:

$(window).unbind('scroll');

it works in my project

CREATE FILE encountered operating system error 5(failed to retrieve text for this error. Reason: 15105)

It's a Windows permissions issue. If you connected to your server using Windows Authentication then that Windows user needs permissions to the file. If you connected to your server using SQL Server authentication then the SQL Server instance account (MSSQL$, e.g. MSSQL$SQLEXPRESS) needs permissions to the file. The other solutions suggesting logging in as an administrator essentially accomplish the same thing (with a bit of a sledgehammer :).

If the database file is in your SQL Server's data folder then it should have inherited the user rights for the SQL Server account from that folder so the SQL Server authentication should have worked. I would recommend fixing the SQL Server instance's account's rights for that folder. If the data file is somewhere else and the SQL Server account does not have permissions then you will likely encounter other problems later. Again, the better solution is to fix the SS account rights. Unless you are always going to log in as administrator...

How to import other Python files?

To import a specific Python file at 'runtime' with a known name:

import os
import sys

...

scriptpath = "../Test/"

# Add the directory containing your module to the Python path (wants absolute paths)
sys.path.append(os.path.abspath(scriptpath))

# Do the import
import MyModule

Iterate Multi-Dimensional Array with Nested Foreach Statement

Use LINQ .Cast<int>() to convert 2D array to IEnumerable<int>.

LINQPad example:

var arr = new int[,] { 
  { 1, 2, 3 }, 
  { 4, 5, 6 } 
};

IEnumerable<int> values = arr.Cast<int>();
Console.WriteLine(values);

Output:

Sequence is 1,2,3,4,5,6

Is it possible to have placeholders in strings.xml for runtime values?

A Direct Kotlin Solution to the problem:

strings.xml

<string name="customer_message">Hello, %1$s!\nYou have %2$d Products in your cart.</string>

kotlinActivityORFragmentFile.kt:

val username = "Andrew"
val products = 1000
val text: String = String.format(
      resources.getString(R.string.customer_message), username, products )

Font is not available to the JVM with Jasper Reports

Create jasper report in multiple languages(Unicode)

1)Install font in ireport desginer

2)create extension of font(we will use it in applications classpath)

3)install font on os(optional)

4)paste all .ttf of font in jre->lib->fonts directory (otherwise web application will throw error font is not available to JVM)

android:drawableLeft margin and/or padding

TextView has an android:drawablePadding property which should do the trick:

android:drawablePadding

The padding between the drawables and the text.

Must be a dimension value, which is a floating point number appended with a unit such as "14.5sp". Available units are: px (pixels), dp (density-independent pixels), sp (scaled pixels based on preferred font size), in (inches), mm (millimeters).

This may also be a reference to a resource (in the form "@[package:]type:name") or theme attribute (in the form "?[package:][type:]name") containing a value of this type.

This corresponds to the global attribute resource symbol drawablePadding.

Is there a function to round a float in C or do I need to write my own?

Sure, you can use roundf(). If you want to round to one decimal, then you could do something like: roundf(10 * x) / 10

Send password when using scp to copy files from one server to another

Just pass with sshpass -p "your password" at the beginning of your scp command

sshpass -p "your password" scp ./abc.txt hostname/abc.txt

Total memory used by Python process?

Current memory usage of the current process on Linux, for Python 2, Python 3, and pypy, without any imports:

def getCurrentMemoryUsage():
    ''' Memory usage in kB '''

    with open('/proc/self/status') as f:
        memusage = f.read().split('VmRSS:')[1].split('\n')[0][:-3]

    return int(memusage.strip())

It reads the status file of the current process, takes everything after VmRSS:, then takes everything before the first newline (isolating the value of VmRSS), and finally cuts off the last 3 bytes which are a space and the unit (kB).
To return, it strips any whitespace and returns it as a number.

Tested on Linux 4.4 and 4.9, but even an early Linux version should work: looking in man proc and searching for the info on the /proc/$PID/status file, it mentions minimum versions for some fields (like Linux 2.6.10 for "VmPTE"), but the "VmRSS" field (which I use here) has no such mention. Therefore I assume it has been in there since an early version.

Format Float to n decimal places

Of note, use of DecimalFormat constructor is discouraged. The javadoc for this class states:

In general, do not call the DecimalFormat constructors directly, since the NumberFormat factory methods may return subclasses other than DecimalFormat.

https://docs.oracle.com/javase/8/docs/api/java/text/DecimalFormat.html

So what you need to do is (for instance):

NumberFormat formatter = NumberFormat.getInstance(Locale.US);
formatter.setMaximumFractionDigits(2);
formatter.setMinimumFractionDigits(2);
formatter.setRoundingMode(RoundingMode.HALF_UP); 
Float formatedFloat = new Float(formatter.format(floatValue));

Google Maps API v3: How to remove all markers?

Most voted answer at top is correct but in case if you have only one marker at a time (like I had in my situation) and every time you need to kill the previous location of that marker and add a new one then you don't need to create whole array of markers and manage it on every push and pop, you can simply just create a variable to store your marker's previous location and can set that to null on creation of new one.

// Global variable to hold marker location.

var previousMarker;

//while adding a new marker

    if(previousMarker != null)
previousMarker.setMap(null);

var marker = new google.maps.Marker({map: resultsMap, position: new google.maps.LatLng(lat_, lang_)});
previousMarker = marker;

Entity Framework - "An error occurred while updating the entries. See the inner exception for details"

I faced the same error :

"An error occurred while updating the entries. See the inner exception for details”

Simply Delete and Recreate the *.edmx file. Its worked for me. the error will gone

How to SHUTDOWN Tomcat in Ubuntu?

If you installed tomcat manually, run the shutdown.sh(/.../tomcat/bin) from the terminal to shut it down easily.

Resolving javax.net.ssl.SSLHandshakeException: sun.security.validator.ValidatorException: PKIX path building failed Error?

Another reason could be an outdated version of JDK. I was using jdk version 1.8.0_60, simply updating to the latest version solved the certificate issue.

Set 4 Space Indent in Emacs in Text Mode

Update: Since Emacs 24.4:

tab-stop-list is now implicitly extended to infinity. Its default value is changed to nil which means a tab stop every tab-width columns.

which means that there's no longer any need to be setting tab-stop-list in the way shown below, as you can keep it set to nil.

Original answer follows...


It always pains me slightly seeing things like (setq tab-stop-list 4 8 12 ................) when the number-sequence function is sitting there waiting to be used.

(setq tab-stop-list (number-sequence 4 200 4))

or

(defun my-generate-tab-stops (&optional width max)
  "Return a sequence suitable for `tab-stop-list'."
  (let* ((max-column (or max 200))
         (tab-width (or width tab-width))
         (count (/ max-column tab-width)))
    (number-sequence tab-width (* tab-width count) tab-width)))

(setq tab-width 4)
(setq tab-stop-list (my-generate-tab-stops))

How to edit a text file in my terminal

Open the file again using vi. and then press the insert button to begin editing it.

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

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

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

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

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

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

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

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

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

Output:

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

Code on Ideone

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

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

List Git aliases

The following works under Linux, MacOSX and Windows (with msysgit).

Use git la to show aliases in .gitconfig

Did I hear 'bash scripting'? ;)

About the 'not needed' part in a comment above, I basically created a man page like overview for my aliases. Why all the fuss? Isn't that complete overkill?

Read on...

I have set the commands like this in my .gitconfig, separated like TAB=TAB:

[alias]
        alias1            =            foo -x -y --z-option
        alias2            =            bar -y --z-option --set-something

and simply defined another alias to grep the TAB= part of the defined aliases. (All other options don't have tabs before and after the '=' in their definition, just spaces.)

Comments not appended to an alias also have a TAB===== appended, so they are shown after grepping.

For better viewing I am piping the grep output into less, like this:

basic version: (black/white)

  #.gitconfig
  [alias]
        # use 'git h <command>' for help, use 'git la' to list aliases  =====
        h     =     help #... <git-command-in-question>
        la    =     "!grep '\t=' ~/.gitconfig | less" 

The '\t=' part matches TAB=.

To have an even better overview of what aliases I have, and since I use the bash console, I colored the output with terminal colors:

  • all '=' are printed in red
  • all '#' are printed in green

advanced version: (colored)

       la      =       "!grep '\t=' ~/.gitconfig | sed -e 's/=/^[[0;31m=^[[0m/g' | sed -e 's/#.*/^[[0;32m&^[[0m/g' | less -R"

Basically the same as above, just sed usage is added to get the color codes into the output.

The -R flag of less is needed to get the colors shown in less.

(I recently found out, that long commands with a scrollbar under their window are not shown correctly on mobile devices: They text is cut off and the scrollbar is simply missing. That might be the case with the last code snippet here, keep that in mind when looking at code snippets here while on the go.)


Why get such magic to work?

I have a like half a mile of aliases, tailored to my needs.
Also some of them change over time, so after all the best idea to have an up-to-date list at hand is parsing the .gitconfig.

A ****short**** excerpt from my .gitconfig aliases:

    #  choose       =====
    a       =       add #...
    aa      =       add .
    ai      =       add -i
    #  unchoose     =====
    rm      =       rm -r #... unversion and delete
    rmc     =       rm -r --cached #... unversion, but leave in working copy
    #  do   =====
    c       =       commit -m #...
    fc      =       commit -am "fastcommit"
    ca      =       commit -am #...
    mc      =       commit # think 'message-commit'
    mca     =       commit -a
    cam     =       commit --amend -C HEAD # update last commit
    #  undo =====
    r       =       reset --hard HEAD
    rv      =       revert HEAD

In my linux or mac workstations also further aliases exist in the .bashrc's, sort of like:

#.bashrc
alias g="git"
alias gh="git h"
alias gla="git la"
function gc { git c "$*" } # this is handy, just type 'gc this is my commitmessage' at prompt

That way no need to type git help submodule, no need for git h submodule, just gh submodule is all that is needed to get the help. It is just some characters, but how often do you type them?

I use all of the following, of course only with shortcuts...

  • add
  • commit
  • commit --amend
  • reset --hard HEAD
  • push
  • fetch
  • rebase
  • checkout
  • branch
  • show-branch (in a lot of variations)
  • shortlog
  • reflog
  • diff (in variations)
  • log (in a lot of variations)
  • status
  • show
  • notes
  • ...

This was just from the top of my head.

I often have to use git without a gui, since a lot of the git commands are not implemented properly in any of the graphical frontends. But everytime I put them to use, it is mostly in the same manner.

On the 'not implemented' part mentioned in the last paragraph:
I have yet to find something that compares to this in a GUI:
sba = show-branch --color=always -a --more=10 --no-name - show all local and remote branches as well as the commits they have within them
ccm = "!git reset --soft HEAD~ && git commit" - change last commit message

From a point of view that is more simple:
How often do you type git add . or git commit -am "..."? Not counting even the rest...
Getting things to work like git aa or git ca "..." in windows,
or with bash aliases gaa/g aa or gca "..."/g ca "..." in linux and on mac's...

For my needs it seemed a smart thing to do, to tailor git commands like this...
... and for easier use I just helped myself for lesser used commands, so i dont have to consult the man pages everytime. Commands are predefined and looking them up is as easy as possible.

I mean, we are programmers after all? Getting things to work like we need them is our job.

Here is an additional screenshot, this works in Windows:

script working with cmd.exe

BONUS: If you are on linux or mac, colorized man pages can help you quite a bit:

colorized man pages

How can I convert a string to boolean in JavaScript?

I do this, which will handle 1=TRUE=yes=YES=true, 0=FALSE=no=NO=false:

BOOL=false
if (STRING)
  BOOL=JSON.parse(STRING.toLowerCase().replace('no','false').replace('yes','true'));

Replace STRING with the name of your string variable.

If it's not null, a numerical value or one of these strings: "true", "TRUE", "false", "FALSE", "yes", "YES", "no", "NO" It will throw an error (intentionally.)

How to update Ruby Version 2.0.0 to the latest version in Mac OSX Yosemite?

If you are on mac, Use rvm to install your specific version of ruby. See https://owanateamachree.medium.com/how-to-install-ruby-using-ruby-version-manager-rvm-on-macos-mojave-ab53f6d8d4ec

Make sure you follow all the steps. This worked for me.

How can I tell how many objects I've stored in an S3 bucket?

The api will return the list in increments of 1000. Check the IsTruncated property to see if there are still more. If there are, you need to make another call and pass the last key that you got as the Marker property on the next call. You would then continue to loop like this until IsTruncated is false.

See this Amazon doc for more info: Iterating Through Multi-Page Results

Oracle timestamp data type

Quite simply the number is the precision of the timestamp, the fraction of a second held in the column:

SQL> create table t23
  2  (ts0 timestamp(0)
  3   , ts3 timestamp(3)
  4  , ts6 timestamp(6)
  5  )
  6  /

Table created.

SQL> insert into t23 values (systimestamp, systimestamp, systimestamp)
  2  /

1 row created.

SQL> select * from t23
  2  /

TS0
---------------------------------------------------------------------------
TS3
---------------------------------------------------------------------------
TS6
---------------------------------------------------------------------------
24-JAN-12 05.57.12 AM
24-JAN-12 05.57.12.003 AM
24-JAN-12 05.57.12.002648 AM


SQL> 

If we don't specify a precision then the timestamp defaults to six places.

SQL> alter table t23 add ts_def timestamp;

Table altered.

SQL> update t23      
  2  set ts_def = systimestamp
  3  /

1 row updated.

SQL> select * from t23
  2  /

TS0
---------------------------------------------------------------------------
TS3
---------------------------------------------------------------------------
TS6
---------------------------------------------------------------------------
TS_DEF
---------------------------------------------------------------------------
24-JAN-12 05.57.12 AM
24-JAN-12 05.57.12.003 AM
24-JAN-12 05.57.12.002648 AM
24-JAN-12 05.59.27.293305 AM


SQL> 

Note that I'm running on Linux so my TIMESTAMP column actually gives me precision to six places i.e. microseconds. This would also be the case on most (all?) flavours of Unix. On Windows the limit is three places i.e. milliseconds. (Is this still true of the most modern flavours of Windows - citation needed).

As might be expected, the documentation covers this. Find out more.


"when you create timestamp(9) this gives you nanos right"

Only if the OS supports it. As you can see, my OEL appliance does not:

SQL> alter table t23 add ts_nano timestamp(9)
  2  /

Table altered.

SQL> update t23 set ts_nano = systimestamp(9)
  2  /

1 row updated.

SQL> select * from t23
  2  /

TS0
---------------------------------------------------------------------------
TS3
---------------------------------------------------------------------------
TS6
---------------------------------------------------------------------------
TS_DEF
---------------------------------------------------------------------------
TS_NANO
---------------------------------------------------------------------------
24-JAN-12 05.57.12 AM
24-JAN-12 05.57.12.003 AM
24-JAN-12 05.57.12.002648 AM
24-JAN-12 05.59.27.293305 AM
24-JAN-12 08.28.03.990557000 AM


SQL> 

(Those trailing zeroes could be a coincidence but they aren't.)

Threading Example in Android

Here is a simple threading example for Android. It's very basic but it should help you to get a perspective.

Android code - Main.java

package test12.tt;

import android.app.Activity;
import android.os.Bundle;
import android.widget.TextView;

public class Test12Activity extends Activity {

    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        final TextView txt1 = (TextView) findViewById(R.id.sm);

        new Thread(new Runnable() { 
            public void run(){        
            txt1.setText("Thread!!");
            }
        }).start();

    }    
}

Android application xml - main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent">

    <TextView  
    android:id = "@+id/sm"
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    android:text="@string/hello"/>

</LinearLayout>

Convert java.util.Date to java.time.LocalDate

If you are using ThreeTen Backport including ThreeTenABP

    Date input = new Date(); // Imagine your Date here
    LocalDate date = DateTimeUtils.toInstant(input)
            .atZone(ZoneId.systemDefault())
            .toLocalDate();

If you are using the backport of JSR 310, either you haven’t got a Date.toInstant() method or it won’t give you the org.threeten.bp.Instant that you need for you further conversion. Instead you need to use the DateTimeUtils class that comes as part of the backport. The remainder of the conversion is the same, so so is the explanation.

Can I have multiple background images using CSS?

_x000D_
_x000D_
#example1 {_x000D_
    background: url(http://www.w3schools.com/css/img_flwr.gif) left top no-repeat, url(http://www.w3schools.com/css/img_flwr.gif) right bottom no-repeat, url(http://www.w3schools.com/css/paper.gif) left top repeat;_x000D_
    padding: 15px;_x000D_
    background-size: 150px, 130px, auto;_x000D_
background-position: 50px 30px, 430px 30px, 130px 130px;_x000D_
}
_x000D_
<!DOCTYPE html>_x000D_
<html>_x000D_
<head>_x000D_
_x000D_
</head>_x000D_
<body>_x000D_
_x000D_
<div id="example1">_x000D_
<h1>Lorem Ipsum Dolor</h1>_x000D_
<p>Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat.</p>_x000D_
<p>Ut wisi enim ad minim veniam, quis nostrud exerci tation ullamcorper suscipit lobortis nisl ut aliquip ex ea commodo consequat.</p>_x000D_
</div>_x000D_
_x000D_
</body>_x000D_
</html>
_x000D_
_x000D_
_x000D_

We can easily add multiple images using CSS3. we can read in detail here http://www.w3schools.com/css/css3_backgrounds.asp

The type initializer for 'System.Data.Entity.Internal.AppConfig' threw an exception

I solved this problem removing DbproviderFactory in the section system.data of the file machine.config, there was some dirty data when I installed fbclient.dll.

C:\Windows\Microsoft.NET\Framework64\v4.0.30319\Config\machine.config C:\Windows\Microsoft.NET\Framework\v4.0.30319\Config\machine.config

  <system.data>
    <!-- <DbProviderFactories><add name="FirebirdClient Data Provider" invariant="FirebirdSql.Data.FirebirdClient" description=".NET Framework Data Provider for Firebird" type="FirebirdSql.Data.FirebirdClient.FirebirdClientFactory, FirebirdSql.Data.FirebirdClient, Version=4.10.0.0, Culture=neutral, PublicKeyToken=3750abcc3150b00c"/><add name="FirebirdClient Data Provider" invariant="FirebirdSql.Data.FirebirdClient" description=".NET Framework Data Provider for Firebird" type="FirebirdSql.Data.FirebirdClient.FirebirdClientFactory, FirebirdSql.Data.FirebirdClient, Version=6.4.0.0, Culture=neutral, PublicKeyToken=3750abcc3150b00c"/> -->
  </system.data>

Delete multiple objects in django

You can delete any QuerySet you'd like. For example, to delete all blog posts with some Post model

Post.objects.all().delete()

and to delete any Post with a future publication date

Post.objects.filter(pub_date__gt=datetime.now()).delete()

You do, however, need to come up with a way to narrow down your QuerySet. If you just want a view to delete a particular object, look into the delete generic view.

EDIT:

Sorry for the misunderstanding. I think the answer is somewhere between. To implement your own, combine ModelForms and generic views. Otherwise, look into 3rd party apps that provide similar functionality. In a related question, the recommendation was django-filter.

Angular-cli from css to scss

As of ng6 this can be accomplished with the following code added to angular.json at the root level:

Manually change in .angular.json:

"schematics": {
  "@schematics/angular:component": {
    "styleext": "scss"
  }
}

Encode/Decode URLs in C++

The Windows API has the functions UrlEscape/UrlUnescape, exported by shlwapi.dll, for this task.

Soft Edges using CSS?

It depends on what type of fading you are looking for.

But with shadow and rounded corners you can get a nice result. Rounded corners because the bigger the shadow, the weirder it will look in the edges unless you balance it out with rounded corners.

http://jsfiddle.net/tLu7u/

also.. http://css3pie.com/

SVN change username

Go to Tortoise SVN --> Settings --> Saved Data.

There is an option to clear Authentication Data, click on the clear button, and it will allow you to select which connection you wanted to clear userid/pwd for.

After you do this, any checkout or update activity, it will reprompt for the userid and password.

What is unit testing and how do you do it?

Unit testing involves breaking your program into pieces, and subjecting each piece to a series of tests.

Usually tests are run as separate programs, but the method of testing varies, depending on the language, and type of software (GUI, command-line, library).

Most languages have unit testing frameworks, you should look into one for yours.

Tests are usually run periodically, often after every change to the source code. The more often the better, because the sooner you will catch problems.

Window.open as modal popup?

That solution will open up a new browser window without the normal features such as address bar and similar.

To implement a modal popup, I suggest you to take a look at jQuery and SimpleModal, which is really slick.

(Here are some simple demos using SimpleModal: http://www.ericmmartin.com/projects/simplemodal-demos/)

Is it possible to set a number to NaN or infinity?

Yes, you can use numpy for that.

import numpy as np
a = arange(3,dtype=float)

a[0] = np.nan
a[1] = np.inf
a[2] = -np.inf

a # is now [nan,inf,-inf]

np.isnan(a[0]) # True
np.isinf(a[1]) # True
np.isinf(a[2]) # True

How to store a byte array in Javascript

You could store the data in an array of strings of some large fixed size. It should be efficient to access any particular character in that array of strings, and to treat that character as a byte.

It would be interesting to see the operations you want to support, perhaps expressed as an interface, to make the question more concrete.

Store a cmdlet's result value in a variable in Powershell

Just access the Priority property of the object returned from the pipeline:

$var = (Get-WSManInstance -enumerate wmicimv2/win32_process).Priority

(This won't work if Get-WSManInstance returns multiple objects.2)

For the second question: to get two properties there are several options, problably the simplest is to have have one variable* containing an object with two separate properties:

$var = (Get-WSManInstance -enumerate wmicimv2/win32_process | select -first 1 Priority, ProcessID)

and then use, assuming only one process:

$var.Priority

and

$var.ProcessID

If there are multiple processes $var will be an array which you can index, so to get the properties of the first process (using the array literal syntax @(...) so it is always a collection1):

$var = @(Get-WSManInstance -enumerate wmicimv2/win32_process | select -first 1 Priority, ProcessID)

and then use:

$var[0].Priority
$var[0].ProcessID

1 PowerShell helpfully for the command line, but not so helpfully in scripts has some extra logic when assigning the result of a pipeline to a variable: if no objects are returned then set $null, if one is returned then that object is assigned, otherwise an array is assigned. Forcing an array returns an array with zero, one or more (respectively) elements.

2 This changes in PowerShell V3 (at the time of writing in Release Candidate), using a member property on an array of objects will return an array of the value of those properties.

How to Get a Specific Column Value from a DataTable?

string countryName = "USA";
DataTable dt = new DataTable();
int id = (from DataRow dr in dt.Rows
              where (string)dr["CountryName"] == countryName
              select (int)dr["id"]).FirstOrDefault();

Set width to match constraints in ConstraintLayout

match_parent is not supported by ConstraintLayout. Set width to 0dp to let it match constraints.

How to get Real IP from Visitor?

If the Proxy is which you trust, you can try: (Assume the Proxy IP is 151.101.2.10)

<?php

$trustProxyIPs = ['151.101.2.10'];

$clientIP  = isset($_SERVER['REMOTE_ADDR']) ? $_SERVER['REMOTE_ADDR'] : NULL;

if (in_array($clientIP, $trustProxyIPs)) {

    $headers = ['HTTP_CLIENT_IP', 'HTTP_X_FORWARDED_FOR'];

    foreach ($headers as $key => $header) {

        if (isset($_SERVER[$header]) && filter_var($_SERVER[$header], FILTER_VALIDATE_IP)) {

            $clientIP = $_SERVER[$header];

            break;
        }
    }
}

echo $clientIP;

This will prevent forged forward header by direct requested clients, and get real IP via trusted Proxies.

Find a file with a certain extension in folder

Use this code for read file with all type of extension file.

string[] sDirectoryInfo = Directory.GetFiles(SourcePath, "*.*");

How to automatically convert strongly typed enum into int?

This seems impossible with the native enum class, but probably you can mock a enum class with a class:

In this case,

enum class b
{
    B1,
    B2
};

would be equivalent to:

class b {
 private:
  int underlying;
 public:
  static constexpr int B1 = 0;
  static constexpr int B2 = 1;
  b(int v) : underlying(v) {}
  operator int() {
      return underlying;
  }
};

This is mostly equivalent to the original enum class. You can directly return b::B1 for in a function with return type b. You can do switch case with it, etc.

And in the spirit of this example you can use templates (possibly together with other things) to generalize and mock any possible object defined by the enum class syntax.

Why does my JavaScript code receive a "No 'Access-Control-Allow-Origin' header is present on the requested resource" error, while Postman does not?

If I understood it right you are doing an XMLHttpRequest to a different domain than your page is on. So the browser is blocking it as it usually allows a request in the same origin for security reasons. You need to do something different when you want to do a cross-domain request. A tutorial about how to achieve that is Using CORS.

When you are using postman they are not restricted by this policy. Quoted from Cross-Origin XMLHttpRequest:

Regular web pages can use the XMLHttpRequest object to send and receive data from remote servers, but they're limited by the same origin policy. Extensions aren't so limited. An extension can talk to remote servers outside of its origin, as long as it first requests cross-origin permissions.

How to find available directory objects on Oracle 11g system?

The ALL_DIRECTORIES data dictionary view will have information about all the directories that you have access to. That includes the operating system path

SELECT owner, directory_name, directory_path
  FROM all_directories

Turning Sonar off for certain code

You can annotate a class or a method with SuppressWarnings

@java.lang.SuppressWarnings("squid:S00112")

squid:S00112 in this case is a Sonar issue ID. You can find this ID in the Sonar UI. Go to Issues Drilldown. Find an issue you want to suppress warnings on. In the red issue box in your code is there a Rule link with a definition of a given issue. Once you click that you will see the ID at the top of the page.

Make child div stretch across width of page

Yes it can be done. You need to use

position:absolute;
left:0;
right:0;

Check working example at http://jsfiddle.net/bJbgJ/3/

Angular 4.3 - HttpClient set params

HttpParams is intended to be immutable. The set and append methods don't modify the existing instance. Instead they return new instances, with the changes applied.

let params = new HttpParams().set('aaa', 'A');    // now it has aaa
params = params.set('bbb', 'B');                  // now it has both

This approach works well with method chaining:

const params = new HttpParams()
  .set('one', '1')
  .set('two', '2');

...though that might be awkward if you need to wrap any of them in conditions.

Your loop works because you're grabbing a reference to the returned new instance. The code you posted that doesn't work, doesn't. It just calls set() but doesn't grab the result.

let httpParams = new HttpParams().set('aaa', '111'); // now it has aaa
httpParams.set('bbb', '222');                        // result has both but is discarded

What's the difference between implementation and compile in Gradle?

Just by looking at the image from the help pages, it makes a lot of sense.

So you have the blue boxes compileClasspath and runtimeClassPath. The compileClasspath is what is required to make a successful build when running gradle build. The libraries that will be present on the classpath when compiling will be all libraries that are configured in your gradle build using either compileOnly or implementation.

Then we have the runtimeClasspath and those are all packages that you added using either implementation or runtimeOnly. All those libraries will be added to the final build file (jar) that you deploy on the server.

As you also see in the image, if you want a library to be both used for compilation but you also want it added to the build file, then implementation should be used.

An example of runtimeOnly can be a database driver.
An example of compileOnly can be servlet-api.
An example of implementation can be spring-core.

Gradle

How to get Enum Value from index in Java?

Here's three ways to do it.

public enum Months {
    JAN(1), FEB(2), MAR(3), APR(4), MAY(5), JUN(6), JUL(7), AUG(8), SEP(9), OCT(10), NOV(11), DEC(12);


    int monthOrdinal = 0;

    Months(int ord) {
        this.monthOrdinal = ord;
    }

    public static Months byOrdinal2ndWay(int ord) {
        return Months.values()[ord-1]; // less safe
    }

    public static Months byOrdinal(int ord) {
        for (Months m : Months.values()) {
            if (m.monthOrdinal == ord) {
                return m;
            }
        }
        return null;
    }
    public static Months[] MONTHS_INDEXED = new Months[] { null, JAN, FEB, MAR, APR, MAY, JUN, JUL, AUG, SEP, OCT, NOV, DEC };

}




import static junit.framework.Assert.assertEquals;

import org.junit.Test;

public class MonthsTest {

@Test
public void test_indexed_access() {
    assertEquals(Months.MONTHS_INDEXED[1], Months.JAN);
    assertEquals(Months.MONTHS_INDEXED[2], Months.FEB);

    assertEquals(Months.byOrdinal(1), Months.JAN);
    assertEquals(Months.byOrdinal(2), Months.FEB);


    assertEquals(Months.byOrdinal2ndWay(1), Months.JAN);
    assertEquals(Months.byOrdinal2ndWay(2), Months.FEB);
}

}

How to implement private method in ES6 class with Traceur

Have you considered using factory functions? They usually are a much better alternative to classes or constructor functions in Javascript. Here is an example of how it works:

function car () {

    var privateVariable = 4

    function privateFunction () {}

    return {

        color: 'red',

        drive: function (miles) {},

        stop: function() {}

        ....

    }

}

Thanks to closures you have access to all private functions and variabels inside the returned object, but you can not access them from outside.

Display a angular variable in my html page

In your template, you have access to all the variables that are members of the current $scope. So, tobedone should be $scope.tobedone, and then you can display it with {{tobedone}}, or [[tobedone]] in your case.

What is null in Java?

Bytecode representation

Java's null has direct JVM support: three instructions are used to implement it:

  • aconst_null: e.g. to set a variable to null as in Object o = null;
  • ifnull and ifnonnull: e.g. to compare an object to null as in if (o == null)

Chapter 6 "The Java Virtual Machine Instruction Set " then mentions the effects of null on other instructions: it throws a NullPointerException for many of them.

2.4. "Reference Types and Values" also mentions null in generic terms:

A reference value may also be the special null reference, a reference to no object, which will be denoted here by null. The null reference initially has no run-time type, but may be cast to any type. The default value of a reference type is null.

"The operation is not valid for the state of the transaction" error and transaction scope

I've encountered this error when my Transaction is nested within another. Is it possible that the stored procedure declares its own transaction or that the calling function declares one?

Can I apply the required attribute to <select> fields in HTML5?

try this, this gonna work, I have tried this and this works.

<!DOCTYPE html>
<html>
<body>

<form action="#">
<select required>
  <option value="">None</option>
  <option value="volvo">Volvo</option>
  <option value="saab">Saab</option>
  <option value="mercedes">Mercedes</option>
  <option value="audi">Audi</option>
</select>
<input type="submit">
</form>

</body>
</html>

How do I view Android application specific cache?

Here is the code: replace package_name by your specific package name.

Intent i = new Intent(android.provider.Settings.ACTION_APPLICATION_DETAILS_SETTINGS);
i.addCategory(Intent.CATEGORY_DEFAULT);
i.setData(Uri.parse("package:package_name"));
startActivity(i);

tar: add all files and directories in current directory INCLUDING .svn and so on

If disk space space is not an issue, this could also be a very easy thing to do:

mkdir backup
cp -r ./* backup
tar -zcvf backup.tar.gz ./backup

TypeError: string indices must be integers, not str // working with dict

I see that you are looking for an implementation of the problem more than solving that error. Here you have a possible solution:

from itertools import chain

def involved(courses, person):
    courses_info = chain.from_iterable(x.values() for x in courses.values())
    return filter(lambda x: x['teacher'] == person, courses_info)

print involved(courses, 'Dave')

The first thing I do is getting the list of the courses and then filter by teacher's name.

How can I listen to the form submit event in javascript?

Based on your requirements you can also do the following without libraries like jQuery:

Add this to your head:

window.onload = function () {
    document.getElementById("frmSubmit").onsubmit = function onSubmit(form) {
        var isValid = true;
        //validate your elems here
        isValid = false;

        if (!isValid) {
            alert("Please check your fields!");
            return false;
        }
        else {
            //you are good to go
            return true;
        }
    }
}

And your form may still look something like:

    <form id="frmSubmit" action="/Submit">
        <input type="submit" value="Submit" />
    </form>

How can I get all the request headers in Django?

Simply you can use HttpRequest.headers from Django 2.2 onward. Following example is directly taken from the official Django Documentation under Request and response objects section.

>>> request.headers
{'User-Agent': 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_6', ...}

>>> 'User-Agent' in request.headers
True
>>> 'user-agent' in request.headers
True

>>> request.headers['User-Agent']
Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_6)
>>> request.headers['user-agent']
Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_6)

>>> request.headers.get('User-Agent')
Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_6)
>>> request.headers.get('user-agent')
Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_6)

JavaScript: How to pass object by value?

If you are using lodash or npm, use lodash's merge function to deep copy all of the object's properties to a new empty object like so:

var objectCopy = lodash.merge({}, originalObject);

https://lodash.com/docs#merge

https://www.npmjs.com/package/lodash.merge

Error: stray '\240' in program

Your Program has invalid/invisible characters in it. You most likely would have picked up these invisible characters when you copy and past code from another website or sometimes a document. Copying the code from the site into another text document and then copying and pasting into your code editor may work, but depending on how long your code is you should just go with typing it out word for word.

Socket accept - "Too many open files"

Just another information about CentOS. In this case, when using "systemctl" to launch process. You have to modify the system file ==> /usr/lib/systemd/system/processName.service .Had this line in the file :

LimitNOFILE=50000

And just reload your system conf :

systemctl daemon-reload

How do I line up 3 divs on the same row?

I'm not sure how I ended up on this post but since most of the answers are using floats, absolute positioning, and other options which aren't optimal now a days, I figured I'd give a new answer that's more up to date on it's standards (float isn't really kosher anymore).

_x000D_
_x000D_
.parent {_x000D_
  display: flex;_x000D_
  flex-direction:row;_x000D_
}_x000D_
_x000D_
.column {_x000D_
  flex: 1 1 0px;_x000D_
  border: 1px solid black;_x000D_
}
_x000D_
<div class="parent">_x000D_
    <div class="column">Column 1</div>_x000D_
    <div class="column">Column 2<br>Column 2<br>Column 2<br>Column 2<br></div>_x000D_
    <div class="column">Column 3</div>_x000D_
</div>
_x000D_
_x000D_
_x000D_

I want to truncate a text or line with ellipsis using JavaScript

Easiest and flexible way: JSnippet DEMO

Function style:

function truncString(str, max, add){
   add = add || '...';
   return (typeof str === 'string' && str.length > max ? str.substring(0,max)+add : str);
};

Prototype:

String.prototype.truncString = function(max, add){
   add = add || '...';
   return (this.length > max ? this.substring(0,max)+add : this);
};

Usage:

str = "testing with some string see console output";

//By prototype:
console.log(  str.truncString(15,'...')  );

//By function call:
console.log(  truncString(str,15,'...')  );

How do I use LINQ Contains(string[]) instead of Contains(string)

Try:

var stringInput = "test";
var listOfNames = GetNames();
var result = from names in listOfNames where names.firstName.Trim().ToLower().Contains(stringInput.Trim().ToLower());
select names;

Python BeautifulSoup extract text between element

soup = BeautifulSoup(html)
for hit in soup.findAll(attrs={'class' : 'MYCLASS'}):
  hit = hit.text.strip()
  print hit

This will print: THIS IS MY TEXT Try this..

How to play only the audio of a Youtube video using HTML 5?

I agree with Tom van der Woerdt. You could use CSS to hide the video (visibility:hidden or overflow:hidden in a div wrapper constrained by height), but that may violate Youtube's policies. Additionally, how could you control the audio (pause, stop, volume, etc.)?

You could instead turn to resources such as http://www.houndbite.com/ to manage audio.

How to generate a HTML page dynamically using PHP?

I was wondering if/how I can 'create' a html page for each database row?

You just need to create one php file that generate an html template, what changes is the text based content on that page. In that page is where you can get a parameter (eg. row id) via POST or GET and then get the info form the database.

I'm assuming this would be better for SEO?

Search Engine as Google interpret that example.php?id=33 and example.php?id=44 are different pages, and yes, this way is better than single listing page from the SEO point of view, so you just need two php files at least (listing.php and single.php), because is better link this pages from the listing.php.

Extra advice:

example.php?id=33 is really ugly and not very seo friendly, maybe you need some url rewriting code. Something like example/properties/property-name is better ;)

What is “2's Complement”?

In simple term 2's Complement is a way to store negative number in Computer Memory. Whereas Positive Numbers are stored as Normal Binary Number.

Let's consider this example,

Computer uses Binary Number System to represent any number.

x = 5;

This is represented as 0101.

x = -5;

When the computer encouters - sign, it computes it's 2's complement and stores it. i.e 5 = 0101 and it's 2's complement is 1011.

Important rules computer uses to process numbers are,

  1. If the first bit is 1 then it must be negative number.
  2. If all the bits except first bit are 0 then it is a positive number because there is no -0 in number system.(1000 is not -0 instead it is positive 8)
  3. If all the bits are 0 then it is 0.
  4. Else it is a positive number.

How to count the number of true elements in a NumPy bool array

That question solved a quite similar question for me and I thought I should share :

In raw python you can use sum() to count True values in a list :

>>> sum([True,True,True,False,False])
3

But this won't work :

>>> sum([[False, False, True], [True, False, True]])
TypeError...

I want to load another HTML page after a specific amount of time

<script>
    setTimeout(function(){
        window.location.href = 'form2.html';
    }, 5000);
</script>

And for home page add only '/'

<script>
    setTimeout(function(){
        window.location.href = '/';
    }, 5000);
</script>

Reloading submodules in IPython

http://shawnleezx.github.io/blog/2015/08/03/some-notes-on-ipython-startup-script/

To avoid typing those magic function again and again, they could be put in the ipython startup script(Name it with .py suffix under .ipython/profile_default/startup. All python scripts under that folder will be loaded according to lexical order), which looks like the following:

from IPython import get_ipython
ipython = get_ipython()

ipython.magic("pylab")
ipython.magic("load_ext autoreload")
ipython.magic("autoreload 2")

How can I compare two lists in python and return matches

Not the most efficient one, but by far the most obvious way to do it is:

>>> a = [1, 2, 3, 4, 5]
>>> b = [9, 8, 7, 6, 5]
>>> set(a) & set(b)
{5}

if order is significant you can do it with list comprehensions like this:

>>> [i for i, j in zip(a, b) if i == j]
[5]

(only works for equal-sized lists, which order-significance implies).

How can I run Tensorboard on a remote server?

While running the tensorboard give one more option --host=ip of your system and then you can access it from other system using http://ip of your host system:6006

FATAL ERROR: CALL_AND_RETRY_LAST Allocation failed - process out of memory

npm install -g increase-memory-limit

increase-memory-limit

OR

  1. Navigate to %appdata% -> npm folder or C:\Users\{user_name}\AppData\Roaming\npm
  2. Open ng.cmd in your favorite editor
  3. Add --max_old_space_size=8192 to the IF and ELSE block

now ng.cmd file looks like this after the change:

@IF EXIST "%~dp0\node.exe" (
  "%~dp0\node.exe" "--max_old_space_size=8192" "%~dp0\node_modules\@angular\cli\bin\ng" %*
) ELSE (
  @SETLOCAL
  @SET PATHEXT=%PATHEXT:;.JS;=;%
  node "--max_old_space_size=8192" "%~dp0\node_modules\@angular\cli\bin\ng" %*
)

React JS get current date

Your problem is that you are naming your component class Date. When you call new Date() within your class, it won't create an instance of the Date you expect it to create (which is likely this Date)- it will try to create an instance of your component class. Then the constructor will try to create another instance, and another instance, and another instance... Until you run out of stack space and get the error you're seeing.

If you want to use Date within your class, try naming your class something different such as Calendar or DateComponent.

The reason for this is how JavaScript deals with name scope: Whenever you create a new named entity, if there is already an entity with that name in scope, that name will stop referring to the previous entity and start referring to your new entity. So if you use the name Date within a class named Date, the name Date will refer to that class and not to any object named Date which existed before the class definition started.

When to use DataContract and DataMember attributes?

Also when you call from http request it will work properly but when your try to call from net.tcp that time you get all this kind stuff

Count number of iterations in a foreach loop

If you just want to find out the number of elements in an array, use count. Now, to answer your question...

How to calculate how many items in a foreach?

$i = 0;
foreach ($Contents as $item) {
    $item[number];// if there are 15 $item[number] in this foreach, I want get the value : 15
    $i++;
}

If you only need the index inside the loop, you could use

foreach($Contents as $index=>$item) {
    // $index goes from 0 up to count($Contents) - 1
    // $item iterates over the elements
}

MySQL SELECT statement for the "length" of the field is greater than 1

Just in case anybody want to find how in oracle and came here (like me), the syntax is

select length(FIELD) from TABLE

just in case ;)

SVN icon overlays not showing properly

I met this problem with TortoiseGit and TortoiseSVN. DropBox renamed its registry entry with more white spaces as prefix " " than I did for Tortoise.

Tortoise directly can open the registry editor by TortoiseGit > Settings > Icon Overlays > Overlay Handlers there click Start registry editor and rename entries so that the first in alphabetical order to be what you want.

How to convert entire dataframe to numeric while preserving decimals?

You might need to do some checking. You cannot safely convert factors directly to numeric. as.character must be applied first. Otherwise, the factors will be converted to their numeric storage values. I would check each column with is.factor then coerce to numeric as necessary.

df1[] <- lapply(df1, function(x) {
    if(is.factor(x)) as.numeric(as.character(x)) else x
})
sapply(df1, class)
#         a         b 
# "numeric" "numeric" 

mysqli::query(): Couldn't fetch mysqli

Reason of the error is wrong initialization of the mysqli object. True construction would be like this:

$DBConnect = new mysqli("localhost","root","","Ladle");

How to hide elements without having them take space on the page?

use style instead like

<div style="display:none;"></div>

Changing image size in Markdown

For all looking for solutions which work in R markdown/ bookdown, these of the previous solutions do/do not work or need slight adaption:

Working

  • Append { width=50% } or { width=50% height=50% }

    • ![foo](foo.png){ width=50% }
    • ![foo](foo.png){ width=50% height=50% }

    • Important: no comma between width and height – i.e. { width=50%, height=30% } won't work!

  • Append { height="36px" width="36px" }

    • ![foo](foo.png){ height="36px" width="36px" }
    • Note: {:height="36px" width="36px"} with colon, as from @sayth, seems not to work with R markdown

Not working:

  • Append =WIDTHxHEIGHT
    • after the URL of the graphic file to resize the image (as from @prosseek)
    • neither =WIDTHxHEIGHT ![foo](foo.png =100x20) nor =WIDTH only ![foo](foo.png =250x) work

How to properly add 1 month from now to current date in moment.js

According to the latest doc you can do the following-

Add a day

moment().add(1, 'days').calendar();

Add Year

moment().add(1, 'years').calendar();

Add Month

moment().add(1, 'months').calendar();

Error: "Adb connection Error:An existing connection was forcibly closed by the remote host"

In my case, resetting ADB didn't make a difference. I also needed to delete my existing virtual devices, which were pretty old, and create new ones.

How to get an HTML element's style values in javascript?

The element.style property lets you know only the CSS properties that were defined as inline in that element (programmatically, or defined in the style attribute of the element), you should get the computed style.

Is not so easy to do it in a cross-browser way, IE has its own way, through the element.currentStyle property, and the DOM Level 2 standard way, implemented by other browsers is through the document.defaultView.getComputedStyle method.

The two ways have differences, for example, the IE element.currentStyle property expect that you access the CCS property names composed of two or more words in camelCase (e.g. maxHeight, fontSize, backgroundColor, etc), the standard way expects the properties with the words separated with dashes (e.g. max-height, font-size, background-color, etc).

Also, the IE element.currentStyle will return all the sizes in the unit that they were specified, (e.g. 12pt, 50%, 5em), the standard way will compute the actual size in pixels always.

I made some time ago a cross-browser function that allows you to get the computed styles in a cross-browser way:

function getStyle(el, styleProp) {
  var value, defaultView = (el.ownerDocument || document).defaultView;
  // W3C standard way:
  if (defaultView && defaultView.getComputedStyle) {
    // sanitize property name to css notation
    // (hypen separated words eg. font-Size)
    styleProp = styleProp.replace(/([A-Z])/g, "-$1").toLowerCase();
    return defaultView.getComputedStyle(el, null).getPropertyValue(styleProp);
  } else if (el.currentStyle) { // IE
    // sanitize property name to camelCase
    styleProp = styleProp.replace(/\-(\w)/g, function(str, letter) {
      return letter.toUpperCase();
    });
    value = el.currentStyle[styleProp];
    // convert other units to pixels on IE
    if (/^\d+(em|pt|%|ex)?$/i.test(value)) { 
      return (function(value) {
        var oldLeft = el.style.left, oldRsLeft = el.runtimeStyle.left;
        el.runtimeStyle.left = el.currentStyle.left;
        el.style.left = value || 0;
        value = el.style.pixelLeft + "px";
        el.style.left = oldLeft;
        el.runtimeStyle.left = oldRsLeft;
        return value;
      })(value);
    }
    return value;
  }
}

The above function is not perfect for some cases, for example for colors, the standard method will return colors in the rgb(...) notation, on IE they will return them as they were defined.

I'm currently working on an article in the subject, you can follow the changes I make to this function here.

Open CSV file via VBA (performance)

Workbooks.Open does work too.

Workbooks.Open ActiveWorkbook.Path & "\Temp.csv", Local:=True

this works/is needed because i use Excel in germany and excel does use "," to separate .csv by default because i use an english installation of windows. even if you use the code below excel forces the "," separator.

Workbooks.Open ActiveWorkbook.Path & "\Test.csv", , , 6, , , , , ";"

and Workbooks.Open ActiveWorkbook.Path & "\Temp.csv", , , 4 +variants of this do not work(!)

why do they even have the delimiter parameter if it is blocked by the Local parameter ?! this makes no sense at all. but now it works.

Android Respond To URL in Intent

You might need to allow different combinations of data in your intent filter to get it to work in different cases (http/ vs https/, www. vs no www., etc).

For example, I had to do the following for an app which would open when the user opened a link to Google Drive forms (www.docs.google.com/forms)

Note that path prefix is optional.

        <intent-filter>
            <action android:name="android.intent.action.VIEW" />
            <category android:name="android.intent.category.DEFAULT" />
            <category android:name="android.intent.category.BROWSABLE" />

            <data android:scheme="http" />
            <data android:scheme="https" />

            <data android:host="www.docs.google.com" />
            <data android:host="docs.google.com" />

            <data android:pathPrefix="/forms" />
        </intent-filter>

javascript unexpected identifier

Either remove one } from end of responseText;}} or from the end of the line

How to find files modified in last x minutes (find -mmin does not work as expected)

The problem is that

find . -mmin -60

outputs:

.
./file1
./file2

Note the line with one dot?
That makes ls list the whole directory exactly the same as when ls -l . is executed.

One solution is to list only files (not directories):

find . -mmin -60 -type f | xargs ls -l

But it is better to use directly the option -exec of find:

find . -mmin -60 -type f -exec ls -l {} \;

Or just:

find . -mmin -60 -type f -ls

Which, by the way is safe even including directories:

find . -mmin -60 -ls

writing to existing workbook using xlwt

The code example is exactly this:

from xlutils.copy import copy
from xlrd import *
w = copy(open_workbook('book1.xls'))
w.get_sheet(0).write(0,0,"foo")
w.save('book2.xls')

You'll need to create book1.xls to test, but you get the idea.

General guidelines to avoid memory leaks in C++

Share and know memory ownership rules across your project. Using the COM rules makes for the best consistency ([in] parameters are owned by the caller, callee must copy; [out] params are owned by the caller, callee must make a copy if keeping a reference; etc.)

When to use RSpec let()?

I have completely replaced all uses of instance variables in my rspec tests to use let(). I've written a quickie example for a friend who used it to teach a small Rspec class: http://ruby-lambda.blogspot.com/2011/02/agile-rspec-with-let.html

As some of the other answers here says, let() is lazy evaluated so it will only load the ones that require loading. It DRYs up the spec and make it more readable. I've in fact ported the Rspec let() code to use in my controllers, in the style of inherited_resource gem. http://ruby-lambda.blogspot.com/2010/06/stealing-let-from-rspec.html

Along with lazy evaluation, the other advantage is that, combined with ActiveSupport::Concern, and the load-everything-in spec/support/ behavior, you can create your very own spec mini-DSL specific to your application. I've written ones for testing against Rack and RESTful resources.

The strategy I use is Factory-everything (via Machinist+Forgery/Faker). However, it is possible to use it in combination with before(:each) blocks to preload factories for an entire set of example groups, allowing the specs to run faster: http://makandra.com/notes/770-taking-advantage-of-rspec-s-let-in-before-blocks

Creating a very simple linked list

public class DynamicLinkedList
{

    private class Node
    {
        private object element;
        private Node next;

        public object Element
        {
            get { return this.element; }
            set { this.element = value; }
        }

        public Node Next
        {
            get { return this.next; }
            set { this.next = value; }
        }

        public Node(object element, Node prevNode)
        {
            this.element = element;
            prevNode.next = this;
        }

        public Node(object element)
        {
            this.element = element;
            next = null;
        }
    }

    private Node head;
    private Node tail;
    private int count;

    public DynamicLinkedList()
    {
        this.head = null;
        this.tail = null;
        this.count = 0;
    }

    public void AddAtLastPosition(object element)
    {
        if (head == null)
        {
            head = new Node(element);
            tail = head;
        }
        else
        {
            Node newNode = new Node(element, tail);
            tail = newNode;
        }

        count++;
    }

    public object GetLastElement()
    {
        object lastElement = null;
        Node currentNode = head;

        while (currentNode != null)
        {
            lastElement = currentNode.Element;
            currentNode = currentNode.Next;
        }

        return lastElement;
    }

}

Testing with:

static void Main(string[] args)
{
    DynamicLinkedList list = new DynamicLinkedList();
    list.AddAtLastPosition(1);
    list.AddAtLastPosition(2);
    list.AddAtLastPosition(3);
    list.AddAtLastPosition(4);
    list.AddAtLastPosition(5);

    object lastElement = list.GetLastElement();
    Console.WriteLine(lastElement);
}

Move existing, uncommitted work to a new branch in Git

If you have been making commits on your main branch while you coded, but you now want to move those commits to a different branch, this is a quick way:

  1. Copy your current history onto a new branch, bringing along any uncommitted changes too:

     git checkout -b <new-feature-branch>
    
  2. Now force the original "messy" branch to roll back: (without switching to it)

     git branch -f <previous-branch> <earlier-commit-id>
    

    For example:

     git branch -f master origin/master
    

    or if you had made 4 commits:

     git branch -f master HEAD~4
    

Warning: git branch -f master origin/master will reset the tracking information for that branch. So if you have configured your master branch to push to somewhere other than origin/master then that configuration will be lost.

Warning: If you rebase after branching, there is a danger that some commits may be lost, which is described here. The only way to avoid that is to create a new history using cherry-pick. That link describes the safest fool-proof method, although less convenient. (If you have uncommitted changes, you may need to git stash at the start and git stash pop at the end.)

Remove Duplicates from range of cells in excel vba

If you got only one column in the range to clean, just add "(1)" to the end. It indicates in wich column of the range Excel will remove the duplicates. Something like:

 Sub norepeat()

    Range("C8:C16").RemoveDuplicates (1)

End Sub

Regards

Good Hash Function for Strings

sdbm:this algorithm was created for sdbm (a public-domain reimplementation of ndbm) database library

static unsigned long sdbm(unsigned char *str)
{   
    unsigned long hash = 0;
    int c;
    while (c = *str++)
            hash = c + (hash << 6) + (hash << 16) - hash;

    return hash;
}

Using Javascript can you get the value from a session attribute set by servlet in the HTML page

Below code may help you to achieve session attribution inside java script:

var name = '<%= session.getAttribute("username") %>';

Iterate over the lines of a string

You can iterate over "a file", which produces lines, including the trailing newline character. To make a "virtual file" out of a string, you can use StringIO:

import io  # for Py2.7 that would be import cStringIO as io

for line in io.StringIO(foo):
    print(repr(line))

How to find the 'sizeof' (a pointer pointing to an array)?

In strings there is a '\0' character at the end so the length of the string can be gotten using functions like strlen. The problem with an integer array, for example, is that you can't use any value as an end value so one possible solution is to address the array and use as an end value the NULL pointer.

#include <stdio.h>
/* the following function will produce the warning:
 * ‘sizeof’ on array function parameter ‘a’ will
 * return size of ‘int *’ [-Wsizeof-array-argument]
 */
void foo( int a[] )
{
    printf( "%lu\n", sizeof a );
}
/* so we have to implement something else one possible
 * idea is to use the NULL pointer as a control value
 * the same way '\0' is used in strings but this way
 * the pointer passed to a function should address pointers
 * so the actual implementation of an array type will
 * be a pointer to pointer
 */
typedef char * type_t; /* line 18 */
typedef type_t ** array_t;
int main( void )
{
    array_t initialize( int, ... );
    /* initialize an array with four values "foo", "bar", "baz", "foobar"
     * if one wants to use integers rather than strings than in the typedef
     * declaration at line 18 the char * type should be changed with int
     * and in the format used for printing the array values 
     * at line 45 and 51 "%s" should be changed with "%i"
     */
    array_t array = initialize( 4, "foo", "bar", "baz", "foobar" );

    int size( array_t );
    /* print array size */
    printf( "size %i:\n", size( array ));

    void aprint( char *, array_t );
    /* print array values */
    aprint( "%s\n", array ); /* line 45 */

    type_t getval( array_t, int );
    /* print an indexed value */
    int i = 2;
    type_t val = getval( array, i );
    printf( "%i: %s\n", i, val ); /* line 51 */

    void delete( array_t );
    /* free some space */
    delete( array );

    return 0;
}
/* the output of the program should be:
 * size 4:
 * foo
 * bar
 * baz
 * foobar
 * 2: baz
 */
#include <stdarg.h>
#include <stdlib.h>
array_t initialize( int n, ... )
{
    /* here we store the array values */
    type_t *v = (type_t *) malloc( sizeof( type_t ) * n );
    va_list ap;
    va_start( ap, n );
    int j;
    for ( j = 0; j < n; j++ )
        v[j] = va_arg( ap, type_t );
    va_end( ap );
    /* the actual array will hold the addresses of those
     * values plus a NULL pointer
     */
    array_t a = (array_t) malloc( sizeof( type_t *) * ( n + 1 ));
    a[n] = NULL;
    for ( j = 0; j < n; j++ )
        a[j] = v + j;
    return a;
}
int size( array_t a )
{
    int n = 0;
    while ( *a++ != NULL )
        n++;
    return n;
}
void aprint( char *fmt, array_t a )
{
    while ( *a != NULL )
        printf( fmt, **a++ );   
}
type_t getval( array_t a, int i )
{
    return *a[i];
}
void delete( array_t a )
{
    free( *a );
    free( a );
}

How to set the environmental variable LD_LIBRARY_PATH in linux

Add

LD_LIBRARY_PATH="/path/you/want1:/path/you/want/2"

to /etc/environment

See the Ubuntu Documentation.

CORRECTION: I should take my own advice and actually read the documentation. It says that this does not apply to LD_LIBRARY_PATH: Since Ubuntu 9.04 Jaunty Jackalope, LD_LIBRARY_PATH cannot be set in $HOME/.profile, /etc/profile, nor /etc/environment files. You must use /etc/ld.so.conf.d/.conf configuration files.* So user1824407's answer is spot on.

Adding quotes to a string in VBScript

I usually do this:

Const Q = """"

Dim a, g
a = "xyz"  
g = "abcd " & Q & a & Q

If you need to wrap strings in quotes more often in your code and find the above approach noisy or unreadable, you can also wrap it in a function:

a = "xyz"  
g = "abcd " & Q(a)

Function Q(s)
  Q = """" & s & """"
End Function

Django auto_now and auto_now_add

class Feedback(models.Model):
   feedback = models.CharField(max_length=100)
   created = models.DateTimeField(auto_now_add=True)
   updated = models.DateTimeField(auto_now=True)

Here, we have created and updated columns that will have a timestamp when created, and when someone modified feedback.

auto_now_add will set time when an instance is created whereas auto_now will set time when someone modified his feedback.

move a virtual machine from one vCenter to another vCenter

Copying the VM files onto an external HDD and then bringing it in to the destination will take a lot longer and requires multiple steps. Using vCenter Converter Standalone Client will do everything for you and is much faster. No external HDD required. Not sure where you got the cloning part from. vCenter Converter Standalone Client is simply copying the VM files by importing and exporting from source to destination, shutdown the source VM, then register the VM at destination and power on. All in one step. Takes about 1 min to set that up vCenter Converter Standalone Client.

Calling C++ class methods via a function pointer

Read this for detail :

// 1 define a function pointer and initialize to NULL

int (TMyClass::*pt2ConstMember)(float, char, char) const = NULL;

// C++

class TMyClass
{
public:
   int DoIt(float a, char b, char c){ cout << "TMyClass::DoIt"<< endl; return a+b+c;};
   int DoMore(float a, char b, char c) const
         { cout << "TMyClass::DoMore" << endl; return a-b+c; };

   /* more of TMyClass */
};
pt2ConstMember = &TMyClass::DoIt; // note: <pt2Member> may also legally point to &DoMore

// Calling Function using Function Pointer

(*this.*pt2ConstMember)(12, 'a', 'b');

How to save username and password in Git?

For windows users look at the .gitconfig file and check what has been configured for the credential helper if you have the following...

[credential "helperselector"] selected = wincred

you'll find the credentials in the Windows Credential Manager.

enter image description here

There you can edit the credential.

EDIT: Wincred has been deprecated, see...

https://github.com/git-for-windows/git-sdk-64/tree/main/mingw64/doc/git-credential-manager

So alternatively you may want to reconfigure git to use the built-in GIT credential manager...

git config --global credential.helper manager

How to get the day name from a selected date?

I use this Extension Method:

public static string GetDayName(this DateTime date)
{
    string _ret = string.Empty; //Only for .NET Framework 4++
    var culture = new System.Globalization.CultureInfo("es-419"); //<- 'es-419' = Spanish (Latin America), 'en-US' = English (United States)
    _ret = culture.DateTimeFormat.GetDayName(date.DayOfWeek); //<- Get the Name     
    _ret = culture.TextInfo.ToTitleCase(_ret.ToLower()); //<- Convert to Capital title
    return _ret;
}

How do I get next month date from today's date and insert it in my database?

If you want a specific date in next month, you can do this:

// Calculate the timestamp
$expire = strtotime('first day of +1 month');

// Format the timestamp as a string
echo date('m/d/Y', $expire);

Note that this actually works more reliably where +1 month can be confusing. For example...

Current Day   | first day of +1 month     | +1 month
---------------------------------------------------------------------------
2015-01-01    | 2015-02-01                | 2015-02-01
2015-01-30    | 2015-02-01                | 2015-03-02  (skips Feb)
2015-01-31    | 2015-02-01                | 2015-03-03  (skips Feb)
2015-03-31    | 2015-04-01                | 2015-05-01  (skips April)
2015-12-31    | 2016-01-01                | 2016-01-31

Importing PNG files into Numpy?

According to the doc, scipy.misc.imread is deprecated starting SciPy 1.0.0, and will be removed in 1.2.0. Consider using imageio.imread instead.

Example:

import imageio

im = imageio.imread('my_image.png')
print(im.shape)

You can also use imageio to load from fancy sources:

im = imageio.imread('http://upload.wikimedia.org/wikipedia/commons/d/de/Wikipedia_Logo_1.0.png')

Edit:

To load all of the *.png files in a specific folder, you could use the glob package:

import imageio
import glob

for im_path in glob.glob("path/to/folder/*.png"):
     im = imageio.imread(im_path)
     print(im.shape)
     # do whatever with the image here

curl POST format for CURLOPT_POSTFIELDS

For CURLOPT_POSTFIELDS, the parameters can either be passed as a urlencoded string like para1=val1&para2=val2&.. or as an array with the field name as key and field data as value

Try the following format :

$data = json_encode(array(
"first"  => "John",
"last" => "Smith"
));

$ch = curl_init(); 
curl_setopt($ch, CURLOPT_URL,$url);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($ch, CURLOPT_POSTFIELDS, $data);
$output = curl_exec($ch);
curl_close($ch);

Jackson: how to prevent field serialization

Jackson has a class named SimpleBeanPropertyFilter that helps to filter fields during serialization and deserialization; not globally. I think that's what you wanted.

@JsonFilter("custom_serializer")
class User {
    private String password;

    //setter, getter..
}

Then in your code:

String[] fieldsToSkip = new String[] { "password" };

ObjectMapper mapper = new ObjectMapper();

final SimpleFilterProvider filter = new SimpleFilterProvider();
filter.addFilter("custom_serializer",
            SimpleBeanPropertyFilter.serializeAllExcept(fieldsToSkip));

mapper.setFilters(filter);

String jsonStr = mapper.writeValueAsString(currentUser);

This will prevent password field to get serialized. Also you will be able to deserialize password fields as it is. Just make sure no filters are applied on the ObjectMapper object.

ObjectMapper mapper = new ObjectMapper();
User user = mapper.readValue(yourJsonStr, User.class);    // user object does have non-null password field

Python POST binary data

This has nothing to do with a malformed upload. The HTTP error clearly specifies 401 unauthorized, and tells you the CSRF token is invalid. Try sending a valid CSRF token with the upload.

More about csrf tokens here:

What is a CSRF token ? What is its importance and how does it work?

How to split a string in Java

You can simply use StringTokenizer to split a string in two or more parts whether there are any type of delimiters:

StringTokenizer st = new StringTokenizer("004-034556", "-");
while(st.hasMoreTokens())
{
    System.out.println(st.nextToken());
}

Syntax for async arrow function

Immediately Invoked Async Arrow Function:

(async () => {
    console.log(await asyncFunction());
})();

Immediately Invoked Async Function Expression:

(async function () {
    console.log(await asyncFunction());
})();

Link a .css on another folder

I dont get it clearly, do you want to link an external css as the structure of files you defined above? If yes then just use the link tag :

    <link rel="stylesheet" type="text/css" href="file.css">

so basically for files that are under your website folder (folder containing your index) you directly call it. For each successive folder use the "/" for example in your case :

    <link rel="stylesheet" type="text/css" href="Fonts/Font1/file name">
    <link rel="stylesheet" type="text/css" href="Fonts/Font2/file name">

Can't get value of input type="file"?

Solution

document.getElementById("uploadPicture").attributes.value.textContent

Why don't self-closing script elements work?

In case anyone's curious, the ultimate reason is that HTML was originally a dialect of SGML, which is XML's weird older brother. In SGML-land, elements can be specified in the DTD as either self-closing (e.g. BR, HR, INPUT), implicitly closeable (e.g. P, LI, TD), or explicitly closeable (e.g. TABLE, DIV, SCRIPT). XML, of course, has no concept of this.

The tag-soup parsers used by modern browsers evolved out of this legacy, although their parsing model isn't pure SGML anymore. And of course, your carefully-crafted XHTML is being treated as badly-written SGML-inspired tag-soup unless you send it with an XML mime type. This is also why...

<p><div>hello</div></p>

...gets interpreted by the browser as:

<p></p><div>hello</div><p></p>

...which is the recipe for a lovely obscure bug that can throw you into fits as you try to code against the DOM.

Convert double to BigDecimal and set BigDecimal Precision

You want to try String.format("%f", d), which will print your double in decimal notation. Don't use BigDecimal at all.

Regarding the precision issue: You are first storing 47.48 in the double c, then making a new BigDecimal from that double. The loss of precision is in assigning to c. You could do

BigDecimal b = new BigDecimal("47.48")

to avoid losing any precision.

Debugging Stored Procedure in SQL Server 2008

Well the answer was sitting right in front of me the whole time.

In SQL Server Management Studio 2008 there is a Debug button in the toolbar. Set a break point in a query window to step through.

I dismissed this functionality at the beginning because I didn't think of stepping INTO the stored procedure, which you can do with ease.

SSMS basically does what FinnNK mentioned with the MSDN walkthrough but automatically.

So easy! Thanks for your help FinnNK.

Edit: I should add a step in there to find the stored procedure call with parameters I used SQL Profiler on my database.

How to read the Stock CPU Usage data

As other answers have pointed, on UNIX systems the numbers represent CPU load averages over 1/5/15 minute periods. But on Linux (and consequently Android), what it represents is something different.

After a kernel patch dating back to 1993 (a great in-depth article on the subject), in Linux the load average numbers no longer strictly represent the CPU load: as the calculation accounts not only for CPU bound processes, but also for processes in uninterruptible wait state - the original goal was to account for I/O bound processes this way, to represent more of a "system load" than just CPU load. The issue is that since 1993 the usage of uninterruptible state has grown in Linux kernel, and it no longer typically represents an I/O bound process. The problem is further exacerbated by some Linux devs using uninterruptible waits as an easy wait to avoid accommodating signals in their implementations. As a result, in Linux (and Android) we can see skewed high load average numbers that do not objectively represent the real load. There are Android user reports about unreasonable high load averages contrasting low CPU utilization. For example, my old Android phone (with 2 CPU cores) normally shown average load of ~12 even when the system and CPUs were idle. Hence, average load numbers in Linux (Android) does not turn out to be a reliable performance metric.

Getting a 500 Internal Server Error on Laravel 5+ Ubuntu 14.04

I read all the comments and suggestions. 500 - HTTP ERROR CODE represents internal server error.

Reasons for this error:

  • These mainly cause due to permission issues
  • Environment variables not found or .env file not found on your root directory
  • PHP extensions problem
  • Database problem

Fix:

  • Set the correct permissions:
  • Run these commands (Ubuntu/Debian)
find /path/to/your/root/dir/ -type f -exec chmod 644 {} \;
find /path/to/your/root/dir/ -type d -exec chmod 755 {} \;

chown -R www-data:www-data /path/to/your/root/dir/

chgrp -R www-data storage bootstrap/cache
chmod -R ug+rwx storage bootstrap/cache
  • If .env file doesn't exist, create one by touch .env and paste your environment variables and then run
   php artisan key:generate
   php artisan cache:clear
   php artisan config:clear
   composer dump-autoload
  • Check your php.ini file and uncomment the extensions you need (In some case you have to install the extension by running this command apt-get install php7.2-[extension-name]
  • Check your database credentials and values in .env file. And grant permissions to the database user for that database.

These are some common problem you likely going to face when deploying your laravel app and once you start getting all these commands, I suggest you to make a script which will save your time.

Why my $.ajax showing "preflight is invalid redirect error"?

My problem was caused by the exact opposite of @ehacinom. My Laravel generated API didn't like the trailing '/' on POST requests. Worked fine on localhost but didn't work when uploaded to server.

Generating random integer from a range

The formula for this is very simple, so try this expression,

 int num = (int) rand() % (max - min) + min;  
 //Where rand() returns a random number between 0.0 and 1.0

Add marker to Google Map on Click

This is actually a documented feature, and can be found here

// This event listener calls addMarker() when the map is clicked.
  google.maps.event.addListener(map, 'click', function(e) {
    placeMarker(e.latLng, map);
  });

  function placeMarker(position, map) {
    var marker = new google.maps.Marker({
      position: position,
      map: map
    });  
    map.panTo(position);
  }

Convert seconds value to hours minutes seconds?

Something really helpful in Java 8

import java.time.LocalTime;

private String ConvertSecondToHHMMSSString(int nSecondTime) {
    return LocalTime.MIN.plusSeconds(nSecondTime).toString();
}

TINYTEXT, TEXT, MEDIUMTEXT, and LONGTEXT maximum storage sizes

From the documentation (MySQL 8) :

      Type | Maximum length
-----------+-------------------------------------
  TINYTEXT |           255 (2 8−1) bytes
      TEXT |        65,535 (216−1) bytes = 64 KiB
MEDIUMTEXT |    16,777,215 (224−1) bytes = 16 MiB
  LONGTEXT | 4,294,967,295 (232−1) bytes =  4 GiB

Note that the number of characters that can be stored in your column will depend on the character encoding.

Two dimensional array list

You can create a list,

ArrayList<String[]> outerArr = new ArrayList<String[]>(); 

and add other lists to it like so:

String[] myString1= {"hey","hey","hey","hey"};  
outerArr .add(myString1);
String[] myString2= {"you","you","you","you"};
outerArr .add(myString2);

Now you can use the double loop below to show everything inside all lists

for(int i=0;i<outerArr.size();i++){

   String[] myString= new String[4]; 
   myString=outerArr.get(i);
   for(int j=0;j<myString.length;j++){
      System.out.print(myString[j]); 
   }
   System.out.print("\n");

}

Argument Exception "Item with Same Key has already been added"

If you want "insert or replace" semantics, use this syntax:

A[key] = value;     // <-- insert or replace semantics

It's more efficient and readable than calls involving "ContainsKey()" or "Remove()" prior to "Add()".

So in your case:

rct3Features[items[0]] = items[1];

Loop through Map in Groovy?

When using the for loop, the value of s is a Map.Entry element, meaning that you can get the key from s.key and the value from s.value

Execution time of C program

I've found that the usual clock(), everyone recommends here, for some reason deviates wildly from run to run, even for static code without any side effects, like drawing to screen or reading files. It could be because CPU changes power consumption modes, OS giving different priorities, etc...

So the only way to reliably get the same result every time with clock() is to run the measured code in a loop multiple times (for several minutes), taking precautions to prevent the compiler from optimizing it out: modern compilers can precompute the code without side effects running in a loop, and move it out of the loop., like i.e. using random input for each iteration.

After enough samples are collected into an array, one sorts that array, and takes the middle element, called median. Median is better than average, because it throws away extreme deviations, like say antivirus taking up all CPU up or OS doing some update.

Here is a simple utility to measure execution performance of C/C++ code, averaging the values near median: https://github.com/saniv/gauge

I'm myself still looking for a more robust and faster way to measure code. One could probably try running the code in controlled conditions on bare metal without any OS, but that will give unrealistic result, because in reality OS does get involved.

x86 has these hardware performance counters, which including the actual number of instructions executed, but they are tricky to access without OS help, hard to interpret and have their own issues ( http://archive.gamedev.net/archive/reference/articles/article213.html ). Still they could be helpful investigating the nature of the bottle neck (data access or actual computations on that data).

How to change python version in anaconda spyder

You can open the preferences (multiple options):

  • keyboard shortcut Ctrl + Alt + Shift + P
  • Tools -> Preferences

And depending on the Spyder version you can change the interpreter in the Python interpreter section (Spyder 3.x):

enter image description here

or in the advanced Console section (Spyder 2.x):

enter image description here

How can I create a table with borders in Android?

A border between cells is doubled in above answers. So, you can try this solution:

<item
    android:left="-1dp"
    android:top="-1dp">

    <shape xmlns:android="http://schemas.android.com/apk/res/android"
           android:shape="rectangle">
        <solid android:color="#fff"/>
        <stroke
            android:width="1dp"
            android:color="#ccc"/>
    </shape>
</item>

How to set Navigation Drawer to be opened from right to left

This answer is useful to set the navigation be open from right to left, but it has no solution to set its icon to be right side. This code can fix it. If you give it the drawer as its first param and ViewCompat.LAYOUT_DIRECTION_RTL as its second param, the entier layout will be set to RTL. It is a quick and simple solution, but I don't think it can be a correct solution for who that want to only set the menu to be opened from right to left and set its icon to be on right side. (Although, it's depended to your purpose.) However, I suggest giving the toolbar instead of the drawer. In this way just the toolbar has become RTL. So I think the combination of these 2 answers can exactly do what you want.

According to these descriptions, your code should be like this:

(Add these lines to onCreate method)

final DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout); // Set it final to fix the error that will be mention below.

    ViewCompat.setLayoutDirection(toolbar, ViewCompat.LAYOUT_DIRECTION_RTL);

    toolbar.setNavigationOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            if (drawer.isDrawerOpen(Gravity.RIGHT))
                drawer.closeDrawer(Gravity.RIGHT);
            else
                drawer.openDrawer(Gravity.RIGHT);
        }
    });

Notice that you should make drawer final, otherwise you will get this error:

Variable 'drawer' is accessed from within inner class, needs to be declared final

And don't forget to use end instead of start in onNavigationItemSelected method:

drawer.closeDrawer(GravityCompat.END);

and in your activity_main.xml

<android.support.v4.widget.DrawerLayout 
   android:id="@+id/drawer_layout"
   tools:openDrawer="end">

   <android.support.design.widget.NavigationView
      android:id="@+id/nav_view"
      android:layout_gravity="end"/>
</android.support.v4.widget.DrawerLayout>

Get text from DataGridView selected cells

Try this:

Dim i = Datagridview1.currentrow.index
textbox1.text = datagridview1.item(columnindex, i).value

It should work :)

How to assign execute permission to a .sh file in windows to be executed in linux

This is not possible. Linux permissions and windows permissions do not translate. They are machine specific. It would be a security hole to allow permissions to be set on files before they even arrive on the target system.

Converting Object to JSON and JSON to Object in PHP, (library like Gson for Java)

for more extendability for large scale apps use oop style with encapsulated fields.

Simple way :-

  class Fruit implements JsonSerializable {

        private $type = 'Apple', $lastEaten = null;

        public function __construct() {
            $this->lastEaten = new DateTime();
        }

        public function jsonSerialize() {
            return [
                'category' => $this->type,
                'EatenTime' => $this->lastEaten->format(DateTime::ISO8601)
            ];
        }
    }

echo json_encode(new Fruit()); //which outputs:

{"category":"Apple","EatenTime":"2013-01-31T11:17:07-0500"}

Real Gson on PHP :-

  1. http://jmsyst.com/libs/serializer
  2. http://symfony.com/doc/current/components/serializer.html
  3. http://framework.zend.com/manual/current/en/modules/zend.serializer.html
  4. http://fractal.thephpleague.com/ - serialize only

Need to navigate to a folder in command prompt

To access another drive, type the drive's letter, followed by ":".

D:

Then enter:

cd d:\windows\movie

Passing just a type as a parameter in C#

There are two common approaches. First, you can pass System.Type

object GetColumnValue(string columnName, Type type)
{
    // Here, you can check specific types, as needed:

    if (type == typeof(int)) { // ...

This would be called like: int val = (int)GetColumnValue(columnName, typeof(int));

The other option would be to use generics:

T GetColumnValue<T>(string columnName)
{
    // If you need the type, you can use typeof(T)...

This has the advantage of avoiding the boxing and providing some type safety, and would be called like: int val = GetColumnValue<int>(columnName);

Convert a Pandas DataFrame to a dictionary

For my use (node names with xy positions) I found @user4179775's answer to the most helpful / intuitive:

import pandas as pd

df = pd.read_csv('glycolysis_nodes_xy.tsv', sep='\t')

df.head()
    nodes    x    y
0  c00033  146  958
1  c00031  601  195
...

xy_dict_list=dict([(i,[a,b]) for i, a,b in zip(df.nodes, df.x,df.y)])

xy_dict_list
{'c00022': [483, 868],
 'c00024': [146, 868],
 ... }

xy_dict_tuples=dict([(i,(a,b)) for i, a,b in zip(df.nodes, df.x,df.y)])

xy_dict_tuples
{'c00022': (483, 868),
 'c00024': (146, 868),
 ... }

Addendum

I later returned to this issue, for other, but related, work. Here is an approach that more closely mirrors the [excellent] accepted answer.

node_df = pd.read_csv('node_prop-glycolysis_tca-from_pg.tsv', sep='\t')

node_df.head()
   node  kegg_id kegg_cid            name  wt  vis
0  22    22       c00022   pyruvate        1   1
1  24    24       c00024   acetyl-CoA      1   1
...

Convert Pandas dataframe to a [list], {dict}, {dict of {dict}}, ...

Per accepted answer:

node_df.set_index('kegg_cid').T.to_dict('list')

{'c00022': [22, 22, 'pyruvate', 1, 1],
 'c00024': [24, 24, 'acetyl-CoA', 1, 1],
 ... }

node_df.set_index('kegg_cid').T.to_dict('dict')

{'c00022': {'kegg_id': 22, 'name': 'pyruvate', 'node': 22, 'vis': 1, 'wt': 1},
 'c00024': {'kegg_id': 24, 'name': 'acetyl-CoA', 'node': 24, 'vis': 1, 'wt': 1},
 ... }

In my case, I wanted to do the same thing but with selected columns from the Pandas dataframe, so I needed to slice the columns. There are two approaches.

  1. Directly:

(see: Convert pandas to dictionary defining the columns used fo the key values)

node_df.set_index('kegg_cid')[['name', 'wt', 'vis']].T.to_dict('dict')

{'c00022': {'name': 'pyruvate', 'vis': 1, 'wt': 1},
 'c00024': {'name': 'acetyl-CoA', 'vis': 1, 'wt': 1},
 ... }
  1. "Indirectly:" first, slice the desired columns/data from the Pandas dataframe (again, two approaches),
node_df_sliced = node_df[['kegg_cid', 'name', 'wt', 'vis']]

or

node_df_sliced2 = node_df.loc[:, ['kegg_cid', 'name', 'wt', 'vis']]

that can then can be used to create a dictionary of dictionaries

node_df_sliced.set_index('kegg_cid').T.to_dict('dict')

{'c00022': {'name': 'pyruvate', 'vis': 1, 'wt': 1},
 'c00024': {'name': 'acetyl-CoA', 'vis': 1, 'wt': 1},
 ... }

The application has stopped unexpectedly: How to Debug?

Filter your log to just Error and look for FATAL EXCEPTION

Converting Float to Dollars and Cents

Building on @JustinBarber's example and noting @eric.frederich's comment, if you want to format negative values like -$1,000.00 rather than $-1,000.00 and don't want to use locale:

def as_currency(amount):
    if amount >= 0:
        return '${:,.2f}'.format(amount)
    else:
        return '-${:,.2f}'.format(-amount)

Can't access to HttpContext.Current

Have you included the System.Web assembly in the application?

using System.Web;

If not, try specifying the System.Web namespace, for example:

 System.Web.HttpContext.Current

Replace and overwrite instead of appending

Using truncate(), the solution could be

import re
#open the xml file for reading:
with open('path/test.xml','r+') as f:
    #convert to string:
    data = f.read()
    f.seek(0)
    f.write(re.sub(r"<string>ABC</string>(\s+)<string>(.*)</string>",r"<xyz>ABC</xyz>\1<xyz>\2</xyz>",data))
    f.truncate()

Rewrite URL after redirecting 404 error htaccess

Try this in your .htaccess:

.htaccess

ErrorDocument 404 http://example.com/404/
ErrorDocument 500 http://example.com/500/
# or map them to one error document:
# ErrorDocument 404 /pages/errors/error_redirect.php
# ErrorDocument 500 /pages/errors/error_redirect.php

RewriteEngine On
RewriteBase /

RewriteCond %{REQUEST_URI} ^/404/$
RewriteRule ^(.*)$ /pages/errors/404.php [L]

RewriteCond %{REQUEST_URI} ^/500/$
RewriteRule ^(.*)$ /pages/errors/500.php [L]

# or map them to one error document:
#RewriteCond %{REQUEST_URI} ^/404/$ [OR]
#RewriteCond %{REQUEST_URI} ^/500/$
#RewriteRule ^(.*)$ /pages/errors/error_redirect.php [L]

The ErrorDocument redirects all 404s to a specific URL, all 500s to another url (replace with your domain).

The Rewrite rules map that URL to your actual 404.php script. The RewriteCond regular expressions can be made more generic if you want, but I think you have to explicitly define all ErrorDocument codes you want to override.

Local Redirect:

Change .htaccess ErrorDocument to a file that exists (must exist, or you'll get an error):

ErrorDocument 404 /pages/errors/404_redirect.php

404_redirect.php

<?php
   header('Location: /404/');
   exit;
?>

Redirect based on error number

Looks like you'll need to specify an ErrorDocument line in .htaccess for every error you want to redirect (see: Apache ErrorDocument and Apache Custom Error). The .htaccess example above has multiple examples in it. You can use the following as the generic redirect script to replace 404_redirect.php above.

error_redirect.php

<?php
   $error_url = $_SERVER["REDIRECT_STATUS"] . '/';
   $error_path = $error_url . '.php';

   if ( ! file_exists($error_path)) {
      // this is the default error if a specific error page is not found
      $error_url = '404/';
   }

   header('Location: ' . $error_url);
   exit;
?>

How do I get the SelectedItem or SelectedIndex of ListView in vb.net?

ListView.FocusedItem.Index 

or you can use foreach loop like this

int index= -1;
foreach (ListViewItem itm in listView1.SelectedItems)
{
    if (itm.Selected)
    {
        index= itm.Index;
    }
}

Using "If cell contains #N/A" as a formula condition.

"N/A" is not a string it is an error, try this:

=if(ISNA(A1),C1)

you have to place this fomula in cell B1 so it will get the value of your formula

Java: convert List<String> to a String

Java 8 solution with java.util.StringJoiner

Java 8 has got a StringJoiner class. But you still need to write a bit of boilerplate, because it's Java.

StringJoiner sj = new StringJoiner(" and ", "" , "");
String[] names = {"Bill", "Bob", "Steve"};
for (String name : names) {
   sj.add(name);
}
System.out.println(sj);

How to get the process ID to kill a nohup process?

Suppose you are executing a java program with nohup you can get java process id by

`ps aux | grep java`

output

xxxxx     9643  0.0  0.0  14232   968 pts/2   

then you can kill the process by typing

sudo kill 9643

or lets say that you need to kill all the java processes then just use

sudo killall java

this command kills all the java processes. you can use this with process. just give the process name at the end of the command

sudo killall {processName}

Django: multiple models in one template using forms

According to Django documentation, inline formsets are for this purpose: "Inline formsets is a small abstraction layer on top of model formsets. These simplify the case of working with related objects via a foreign key".

See https://docs.djangoproject.com/en/dev/topics/forms/modelforms/#inline-formsets

Using Service to run background and create notification

Your error is in UpdaterServiceManager in onCreate and showNotification method.

You are trying to show notification from Service using Activity Context. Whereas Every Service has its own Context, just use the that. You don't need to pass a Service an Activity's Context.I don't see why you need a specific Activity's Context to show Notification.

Put your createNotification method in UpdateServiceManager.class. And remove CreateNotificationActivity not from Service.

You cannot display an application window/dialog through a Context that is not an Activity. Try passing a valid activity reference

How do I remove a file from the FileList

You may wish to create an array and use that instead of the read-only filelist.

var myReadWriteList = new Array();
// user selects files later...
// then as soon as convenient... 
myReadWriteList = FileListReadOnly;

After that point do your uploading against your list instead of the built in list. I am not sure of the context you are working in but I am working with a jquery plugin I found and what I had to do was take the plugin's source and put it in the page using <script> tags. Then above the source I added my array so that it can act as a global variable and the plugin could reference it.

Then it was just a matter of swapping out the references.

I think this would allow you to also add drag & drop as again, if the built in list is read-only then how else could you get the dropped files into the list?

:))

"SELECT ... IN (SELECT ...)" query in CodeIgniter

Note that these solutions use the Code Igniter Active Records Class

This method uses sub queries like you wish but you should sanitize $countryId yourself!

$this->db->select('username')
         ->from('user')
         ->where('`locationId` in', '(select `locationId` from `locations` where `countryId` = '.$countryId.')', false)
         ->get();

Or this method would do it using joins and will sanitize the data for you (recommended)!

$this->db->select('username')
         ->from('users')
         ->join('locations', 'users.locationid = locations.locationid', 'inner')
         ->where('countryid', $countryId)
         ->get();

What's better at freeing memory with PHP: unset() or $var = null

unset code if not freeing immediate memory is still very helpful and would be a good practice to do this each time we pass on code steps before we exit a method. take note its not about freeing immediate memory. immediate memory is for CPU, what about secondary memory which is RAM.

and this also tackles about preventing memory leaks.

please see this link http://www.hackingwithphp.com/18/1/11/be-wary-of-garbage-collection-part-2

i have been using unset for a long time now.

better practice like this in code to instanly unset all variable that have been used already as array.

$data['tesst']='';
$data['test2']='asdadsa';
....
nth.

and just unset($data); to free all variable usage.

please see related topic to unset

How important is it to unset variables in PHP?

[bug]

How do I concatenate strings in Swift?

You can concatenate strings a number of ways:

let a = "Hello"
let b = "World"

let first = a + ", " + b
let second = "\(a), \(b)"

You could also do:

var c = "Hello"
c += ", World"

I'm sure there are more ways too.

Bit of description

let creates a constant. (sort of like an NSString). You can't change its value once you have set it. You can still add it to other things and create new variables though.

var creates a variable. (sort of like NSMutableString) so you can change the value of it. But this has been answered several times on Stack Overflow, (see difference between let and var).

Note

In reality let and var are very different from NSString and NSMutableString but it helps the analogy.

Where IN clause in LINQ

public List<State> GetcountryCodeStates(List<string> countryCodes)
{
    List<State> states = new List<State>();
    states = (from a in _objdatasources.StateList.AsEnumerable()
    where countryCodes.Any(c => c.Contains(a.CountryCode))
    select a).ToList();
    return states;
}

right click context menu for datagridview

While this question is old, the answers aren't proper. Context menus have their own events on DataGridView. There is an event for row context menu and cell context menu.

The reason for which these answers aren't proper is they do not account for different operation schemes. Accessibility options, remote connections, or Metro/Mono/Web/WPF porting might not work and keyboard shortcuts will down right fail (Shift+F10 or Context Menu key).

Cell selection on right mouse click has to be handled manually. Showing the context menu does not need to be handled as this is handled by the UI.

This completely mimics the approach used by Microsoft Excel. If a cell is part of a selected range, the cell selection doesn't change and neither does CurrentCell. If it isn't, the old range is cleared and the cell is selected and becomes CurrentCell.

If you are unclear on this, CurrentCell is where the keyboard has focus when you press the arrow keys. Selected is whether it is part of SelectedCells. The context menu will show on right click as handled by the UI.

private void dgvAccount_CellMouseDown(object sender, DataGridViewCellMouseEventArgs e)
{
    if (e.ColumnIndex != -1 && e.RowIndex != -1 && e.Button == System.Windows.Forms.MouseButtons.Right)
    {
        DataGridViewCell c = (sender as DataGridView)[e.ColumnIndex, e.RowIndex];
        if (!c.Selected)
        {
            c.DataGridView.ClearSelection();
            c.DataGridView.CurrentCell = c;
            c.Selected = true;
        }
    }
}

Keyboard shortcuts do not show the context menu by default, so we have to add them in.

private void dgvAccount_KeyDown(object sender, KeyEventArgs e)
{
    if ((e.KeyCode == Keys.F10 && e.Shift) || e.KeyCode == Keys.Apps)
    {
        e.SuppressKeyPress = true;
        DataGridViewCell currentCell = (sender as DataGridView).CurrentCell;
        if (currentCell != null)
        {
            ContextMenuStrip cms = currentCell.ContextMenuStrip;
            if (cms != null)
            {
                Rectangle r = currentCell.DataGridView.GetCellDisplayRectangle(currentCell.ColumnIndex, currentCell.RowIndex, false);
                Point p = new Point(r.X + r.Width, r.Y + r.Height);
                cms.Show(currentCell.DataGridView, p);
            }
        }
    }
}

I've reworked this code to work statically, so you can copy and paste them into any event.

The key is to use CellContextMenuStripNeeded since this will give you the context menu.

Here's an example using CellContextMenuStripNeeded where you can specify which context menu to show if you want to have different ones per row.

In this context MultiSelect is True and SelectionMode is FullRowSelect. This is just for the example and not a limitation.

private void dgvAccount_CellContextMenuStripNeeded(object sender, DataGridViewCellContextMenuStripNeededEventArgs e)
{
    DataGridView dgv = (DataGridView)sender;

    if (e.RowIndex == -1 || e.ColumnIndex == -1)
        return;
    bool isPayment = true;
    bool isCharge = true;
    foreach (DataGridViewRow row in dgv.SelectedRows)
    {
        if ((string)row.Cells["P/C"].Value == "C")
            isPayment = false;
        else if ((string)row.Cells["P/C"].Value == "P")
            isCharge = false;
    }
    if (isPayment)
        e.ContextMenuStrip = cmsAccountPayment;
    else if (isCharge)
        e.ContextMenuStrip = cmsAccountCharge;
}

private void cmsAccountPayment_Opening(object sender, CancelEventArgs e)
{
    int itemCount = dgvAccount.SelectedRows.Count;
    string voidPaymentText = "&Void Payment"; // to be localized
    if (itemCount > 1)
        voidPaymentText = "&Void Payments"; // to be localized
    if (tsmiVoidPayment.Text != voidPaymentText) // avoid possible flicker
        tsmiVoidPayment.Text = voidPaymentText;
}

private void cmsAccountCharge_Opening(object sender, CancelEventArgs e)
{
    int itemCount = dgvAccount.SelectedRows.Count;
    string deleteChargeText = "&Delete Charge"; //to be localized
    if (itemCount > 1)
        deleteChargeText = "&Delete Charge"; //to be localized
    if (tsmiDeleteCharge.Text != deleteChargeText) // avoid possible flicker
        tsmiDeleteCharge.Text = deleteChargeText;
}

private void tsmiVoidPayment_Click(object sender, EventArgs e)
{
    int paymentCount = dgvAccount.SelectedRows.Count;
    if (paymentCount == 0)
        return;

    bool voidPayments = false;
    string confirmText = "Are you sure you would like to void this payment?"; // to be localized
    if (paymentCount > 1)
        confirmText = "Are you sure you would like to void these payments?"; // to be localized
    voidPayments = (MessageBox.Show(
                    confirmText,
                    "Confirm", // to be localized
                    MessageBoxButtons.YesNo,
                    MessageBoxIcon.Warning,
                    MessageBoxDefaultButton.Button2
                   ) == DialogResult.Yes);
    if (voidPayments)
    {
        // SQLTransaction Start
        foreach (DataGridViewRow row in dgvAccount.SelectedRows)
        {
            //do Work    
        }
    }
}

private void tsmiDeleteCharge_Click(object sender, EventArgs e)
{
    int chargeCount = dgvAccount.SelectedRows.Count;
    if (chargeCount == 0)
        return;

    bool deleteCharges = false;
    string confirmText = "Are you sure you would like to delete this charge?"; // to be localized
    if (chargeCount > 1)
        confirmText = "Are you sure you would like to delete these charges?"; // to be localized
    deleteCharges = (MessageBox.Show(
                    confirmText,
                    "Confirm", // to be localized
                    MessageBoxButtons.YesNo,
                    MessageBoxIcon.Warning,
                    MessageBoxDefaultButton.Button2
                   ) == DialogResult.Yes);
    if (deleteCharges)
    {
        // SQLTransaction Start
        foreach (DataGridViewRow row in dgvAccount.SelectedRows)
        {
            //do Work    
        }
    }
}

Assign null to a SqlParameter

In my opinion the better way is to do this with the Parameters property of the SqlCommand class:

public static void AddCommandParameter(SqlCommand myCommand)
{
    myCommand.Parameters.AddWithValue(
        "@AgeIndex",
        (AgeItem.AgeIndex== null) ? DBNull.Value : AgeItem.AgeIndex);
}

smooth scroll to top

Elegant easy solution using jQuery.

<script>
    function call() {
        var body = $("html, body");
        body.stop().animate({scrollTop:0}, 500, 'swing', function() {
        });
    }
</script>

and in your html : <div onclick="call()"><img src="../img/[email protected]"></div>

IntelliJ does not show project folders

For me, it happens when i set Project SDK as JAVA SDK 14 in a react-native project. Upon unset, all the folders show up again.

How do I return a proper success/error message for JQuery .ajax() using PHP?

I had the same issue. My problem was that my header type wasn't set properly.

I just added this before my json echo

header('Content-type: application/json');

How to make a simple modal pop up form using jquery and html?

I have placed here complete bins for above query. you can check demo link too.

Demo: http://codebins.com/bin/4ldqp78/2/How%20to%20make%20a%20simple%20modal%20pop

HTML

<div id="panel">
  <input type="button" class="button" value="1" id="btn1">
  <input type="button" class="button" value="2" id="btn2">
  <input type="button" class="button" value="3" id="btn3">
  <br>
  <input type="text" id="valueFromMyModal">
  <!-- Dialog Box-->
  <div class="dialog" id="myform">
    <form>
      <label id="valueFromMyButton">
      </label>
      <input type="text" id="name">
      <div align="center">
        <input type="button" value="Ok" id="btnOK">
      </div>
    </form>
  </div>
</div>

JQuery

$(function() {
    $(".button").click(function() {
        $("#myform #valueFromMyButton").text($(this).val().trim());
        $("#myform input[type=text]").val('');
        $("#myform").show(500);
    });
    $("#btnOK").click(function() {
        $("#valueFromMyModal").val($("#myform input[type=text]").val().trim());
        $("#myform").hide(400);
    });
});

CSS

.button{
  border:1px solid #333;
  background:#6479fd;
}
.button:hover{
  background:#a4a9fd;
}
.dialog{
  border:5px solid #666;
  padding:10px;
  background:#3A3A3A;
  position:absolute;
  display:none;
}
.dialog label{
  display:inline-block;
  color:#cecece;
}
input[type=text]{
  border:1px solid #333;
  display:inline-block;
  margin:5px;
}
#btnOK{
  border:1px solid #000;
  background:#ff9999;
  margin:5px;
}

#btnOK:hover{
  border:1px solid #000;
  background:#ffacac;
}

Demo: http://codebins.com/bin/4ldqp78/2/How%20to%20make%20a%20simple%20modal%20pop

How can I download HTML source in C#

The newest, most recent, up to date answer
This post is really old (it's 7 years old when I answered it), so no one of the other answers used the new and recommended way, which is HttpClient class.


HttpClient is considered the new API and it should replace the old ones (WebClient and WebRequest)

string url = "page url";
HttpClient client = new HttpClient();
using (HttpResponseMessage response = client.GetAsync(url).Result)
{
   using (HttpContent content = response.Content)
   {
      string result = content.ReadAsStringAsync().Result;
   }
}

for more information about how to use the HttpClient class (especially in async cases), you can refer this question


NOTE 1: If you want to use async/await

string url = "page url";
HttpClient client = new HttpClient();   // actually only one object should be created by Application
using (HttpResponseMessage response = await client.GetAsync(url))
{
   using (HttpContent content = response.Content)
   {
      string result = await content.ReadAsStringAsync();
   }
}

NOTE 2: If use C# 8 features

string url = "page url";
HttpClient client = new HttpClient();
using HttpResponseMessage response = await client.GetAsync(url);
using HttpContent content = response.Content;
string result = await content.ReadAsStringAsync();

How to select lines between two marker patterns which may occur multiple times with awk/sed

sed '/^abc$/,/^mno$/!d;//d' file

golfs two characters better than ppotong's {//!b};d

The empty forward slashes // mean: "reuse the last regular expression used". and the command does the same as the more understandable:

sed '/^abc$/,/^mno$/!d;/^abc$/d;/^mno$/d' file

This seems to be POSIX:

If an RE is empty (that is, no pattern is specified) sed shall behave as if the last RE used in the last command applied (either as an address or as part of a substitute command) was specified.

Inheritance and init method in Python

A simple change in Num2 class like this:

super().__init__(num) 

It works in python3.

class Num:
        def __init__(self,num):
                self.n1 = num

class Num2(Num):
        def __init__(self,num):
                super().__init__(num)
                self.n2 = num*2
        def show(self):
                print (self.n1,self.n2)

mynumber = Num2(8)
mynumber.show()

How can I repeat a character in Bash?

Slightly longer version, but if you have to use pure Bash for some reason, you can use a while loop with an incrementing variable:

n=0; while [ $n -lt 100 ]; do n=$((n+1)); echo -n '='; done

PHP compare two arrays and get the matched values not the difference

OK.. We needed to compare a dynamic number of product names...

There's probably a better way... but this works for me...

... because....Strings are just Arrays of characters.... :>}

//  Compare Strings ...  Return Matching Text and Differences with Product IDs...

//  From MySql...
$productID1 = 'abc123';
$productName1 = "EcoPlus Premio Jet 600";   

$productID2 = 'xyz789';
$productName2 = "EcoPlus Premio Jet 800";   

$ProductNames = array(
    $productID1 => $productName1,
    $productID2 => $productName2
);


function compareNames($ProductNames){   

    //  Convert NameStrings to Arrays...    
    foreach($ProductNames as $id => $product_name){
        $Package1[$id] = explode(" ",$product_name);    
    }

    // Get Matching Text...
    $Matching = call_user_func_array('array_intersect', $Package1 );
    $MatchingText = implode(" ",$Matching);

    //  Get Different Text...
    foreach($Package1 as $id => $product_name_chunks){
        $Package2 = array($product_name_chunks,$Matching);
        $diff = call_user_func_array('array_diff', $Package2 );
        $DifferentText[$id] = trim(implode(" ", $diff));
    }

    $results[$MatchingText]  = $DifferentText;              
    return $results;    
}

$Results =  compareNames($ProductNames);

print_r($Results);

// Gives us this...
[EcoPlus Premio Jet] 
        [abc123] => 600
        [xyz789] => 800

Apache 2.4.3 (with XAMPP 1.8.1) not starting in windows 8

I had this problem and then I ran "apache_start.bat" the error in german told me there was a problem with line 51 in httpd-ssl.conf which is

SSLCipherSuite HIGH:MEDIUM:!aNULL:!MD5

What I did was comment lines 163 (ssl module) and 522 (httpd-ssl.conf include) in httpd.conf; I don't need ssl for development, so that solved it for me.

Excel VBA - select multiple columns not in sequential order

Some of the code looks a bit complex to me. This is very simple code to select only the used rows in two discontiguous columns D and H. It presumes the columns are of unequal length and thus more flexible vs if the columns were of equal length.

As you most likely surmised 4=column D and 8=column H

Dim dlastRow As Long
Dim hlastRow As Long

dlastRow = ActiveSheet.Cells(Rows.Count, 4).End(xlUp).Row
hlastRow = ActiveSheet.Cells(Rows.Count, 8).End(xlUp).Row
Range("D2:D" & dlastRow & ",H2:H" & hlastRow).Select

Hope you find useful - DON'T FORGET THAT COMMA BEFORE THE SECOND COLUMN, AS I DID, OR IT WILL BOMB!!

delete word after or around cursor in VIM

The below works for Normal mode: I agree with Dan Olson's answer that you should probably be in normal mode for most deletions. More details below.

If the cursor is inside the word:
diw to delete in the word (doesn't include spaces)
daw to delete around the word (includes spaces before the next word).

If the cursor is at the start of the word, just press dw.

This can be multiplied by adding the usual numbers for movement, e.g. 2w to move forward 2 words, so d2w deletes two words.

Insert Mode ^w
The idea of using hjkl for movement in Vim is that it's more productive to keep your hands on the home row. At the end of a word ^w works great to quickly delete the word. If you've gone into insert mode, entered some text and used the arrow keys to end up in the middle of the word you've gone against the home-row philosophy.
If you're in normal mode and want to change the word you can simply use the c (change) rather than d (delete) if you'd like to completely change the word, and re-enter insert mode without having to press i to get back to typing.

Error loading the SDK when Eclipse starts

I faced the same issue. To get rid of this issue, I followed the below steps and it worked for me.

  1. Close Eclipse
  2. Open file devices.xml(location of this will be shown in the error message) in a text editor.
  3. Comment out all tags contains d:skin
  4. Save files
  5. Reopen Eclipse

Java Object Null Check for method

You simply compare your object to null using the == (or !=) operator. E.g.:

public static double calculateInventoryTotal(Book[] books) {
    // First null check - the entire array
    if (books == null) {
        return 0;
    }

    double total = 0;

    for (int i = 0; i < books.length; i++) {
        // second null check - each individual element
        if (books[i] != null) {
            total += books[i].getPrice();
        }
    }

    return total;
}

Simulating Button click in javascript

Use this

jQuery("input.second").trigger("click");

Create GUI using Eclipse (Java)

There are lot of GUI designers even like Eclipse plugins, just few of them could use both, Swing and SWT..

WindowBuilder Pro GUI Designer - eclipse marketplace

WindowBuilder Pro GUI Designer - Google code home page

and

Jigloo SWT/Swing GUI Builder - eclipse market place

Jigloo SWT/Swing GUI Builder - home page

The window builder is quite better tool..

But IMHO, GUIs created by those tools have really ugly and unmanageable code..

How to make Visual Studio copy a DLL file to the output directory?

Add builtin COPY in project.csproj file:

  <Project>
    ...
    <Target Name="AfterBuild">
      <Copy SourceFiles="$(ProjectDir)..\..\Lib\*.dll" DestinationFolder="$(OutDir)Debug\bin" SkipUnchangedFiles="false" />
      <Copy SourceFiles="$(ProjectDir)..\..\Lib\*.dll" DestinationFolder="$(OutDir)Release\bin" SkipUnchangedFiles="false" />
    </Target>
  </Project>

How to list files in a directory in a C program?

An example, available for POSIX compliant systems :

/*
 * This program displays the names of all files in the current directory.
 */

#include <dirent.h> 
#include <stdio.h> 

int main(void) {
  DIR *d;
  struct dirent *dir;
  d = opendir(".");
  if (d) {
    while ((dir = readdir(d)) != NULL) {
      printf("%s\n", dir->d_name);
    }
    closedir(d);
  }
  return(0);
}

Beware that such an operation is platform dependant in C.

Source : http://faq.cprogramming.com/cgi-bin/smartfaq.cgi?answer=1046380353&id=1044780608

Are PDO prepared statements sufficient to prevent SQL injection?

No this is not enough (in some specific cases)! By default PDO uses emulated prepared statements when using MySQL as a database driver. You should always disable emulated prepared statements when using MySQL and PDO:

$dbh->setAttribute(PDO::ATTR_EMULATE_PREPARES, false);

Another thing that always should be done it set the correct encoding of the database:

$dbh = new PDO('mysql:dbname=dbtest;host=127.0.0.1;charset=utf8', 'user', 'pass');

Also see this related question: How can I prevent SQL injection in PHP?

Also note that that only is about the database side of the things you would still have to watch yourself when displaying the data. E.g. by using htmlspecialchars() again with the correct encoding and quoting style.

jQuery get selected option value (not the text, but the attribute 'value')

this code work very well for me: this return the value of selected option. $('#select_id').find('option:selected').val();

Setting CSS pseudo-class rules from JavaScript

In jquery you can easily set hover pseudo classes.

$("p").hover(function(){
$(this).css("background-color", "yellow");
}, function(){
$(this).css("background-color", "pink");
});