Programs & Examples On #Mod python

Mod_python is an Apache module that embeds the Python interpreter within the server.

Mysql adding user for remote access

An alternative way is to use MySql Workbench. Go to Administration -> Users and privileges -> and change 'localhost' with '%' in 'Limit to Host Matching' (From host) attribute for users you wont to give remote access Or create new user ( Add account button ) with '%' on this attribute instead localhost.

How to give environmental variable path for file appender in configuration file in log4j

you CAN give it environment variables. Just preppend env: before the variable name, like this:


Converting Dictionary to List?

Converting from dict to list is made easy in Python. Three examples:

>> d = {'a': 'Arthur', 'b': 'Belling'}

>> d.items()
[('a', 'Arthur'), ('b', 'Belling')]

>> d.keys()
['a', 'b']

>> d.values()
['Arthur', 'Belling']

The maximum recursion 100 has been exhausted before statement completion

Specify the maxrecursion option at the end of the query:

from EmployeeTree
option (maxrecursion 0)

That allows you to specify how often the CTE can recurse before generating an error. Maxrecursion 0 allows infinite recursion.

Python: Number of rows affected by cursor.execute("SELECT ...)

To get the number of selected rows I usually use the following:

count = (len(cursor.fetchall))

Why is <deny users="?" /> included in the following example?

Example 1 is for applications using forms authenication. This is common practice for internet applications because user is unauthenticated until it is authentcation against some security module.

Example 2 is for application using windows authenication. Windows Authentication uses Active Directory to authenticate users. The will prevent access to your application. I use this feature on intranet applications.

How to get public directory?

Use public_path()

For reference:

// Path to the project's root folder    
echo base_path();

// Path to the 'app' folder    
echo app_path();        

// Path to the 'public' folder    
echo public_path();

// Path to the 'storage' folder    
echo storage_path();

// Path to the 'storage/app' folder    
echo storage_path('app');

Input size vs width

I just got through fighting with a table that I couldn't make any smaller no matter which element I tried to make smaller the width of the table stayed the same. I searched using firebug but couldn't find the element that was setting the width so high.

Finally I tried changing the size attribute of the input text elements and that fixed it. For some reason the size attribute over-rode the css widths. I was using jQuery to dynamically add rows to a table and it was these rows that contained the inputs. So perhaps when it comes to dynamically adding inputs using the appendTo() function maybe it is better to set the size attribute along with the width.

Impact of Xcode build options "Enable bitcode" Yes/No

Bitcode makes crash reporting harder. Here is a quote from HockeyApp (which also true for any other crash reporting solutions):

When uploading an app to the App Store and leaving the "Bitcode" checkbox enabled, Apple will use that Bitcode build and re-compile it on their end before distributing it to devices. This will result in the binary getting a new UUID and there is an option to download a corresponding dSYM through Xcode.

Note: the answer was edited on Jan 2016 to reflect most recent changes

How to write MySQL query where A contains ( "a" or "b" )

I user for searching the size of motorcycle :

For example : Data = "Tire cycle size 70 / 90 - 16"

i can search with "70 90 16"

$searchTerms = preg_split("/[\s,-\/?!]+/", $itemName);

foreach ($searchTerms as $term) {
        $term = trim($term);
            if (!empty($term)) {
            $searchTermBits[] = "name LIKE '%$term%'";

$query = "SELECT * FROM item WHERE " .implode(' AND ', $searchTermBits);

What is the difference between an abstract function and a virtual function?

To my understanding:

Abstract Methods:

Only the abstract class can hold abstract methods. Also the derived class need to implement the method and no implementation is provided in the class.

Virtual Methods:

A class can declare these and also provide the implementation of the same. Also the derived class need to implement of the method to override it.

Read text from response

The accepted answer does not correctly dispose the WebResponse or decode the text. Also, there's a new way to do this in .NET 4.5.

To perform an HTTP GET and read the response text, do the following.

.NET 1.1 - 4.0

public static string GetResponseText(string address)
    var request = (HttpWebRequest)WebRequest.Create(address);

    using (var response = (HttpWebResponse)request.GetResponse())
        var encoding = Encoding.GetEncoding(response.CharacterSet);

        using (var responseStream = response.GetResponseStream())
        using (var reader = new StreamReader(responseStream, encoding))
            return reader.ReadToEnd();

.NET 4.5

private static readonly HttpClient httpClient = new HttpClient();

public static async Task<string> GetResponseText(string address)
    return await httpClient.GetStringAsync(address);

How to convert JSON object to JavaScript array?

As simple as this !

var json_data = {"2013-01-21":1,"2013-01-22":7};
var result = [json_data];

Return row number(s) for a particular value in a column in a dataframe

Use which(mydata_2$height_chad1 == 2585)

Short example

df <- data.frame(x = c(1,1,2,3,4,5,6,3),
                 y = c(5,4,6,7,8,3,2,4))
  x y
1 1 5
2 1 4
3 2 6
4 3 7
5 4 8
6 5 3
7 6 2
8 3 4

which(df$x == 3)
[1] 4 8

length(which(df$x == 3))
[1] 2

count(df, vars = "x")
  x freq
1 1    2
2 2    1
3 3    2
4 4    1
5 5    1
6 6    1

df[which(df$x == 3),]
  x y
4 3 7
8 3 4

As Matt Weller pointed out, you can use the length function. The count function in plyr can be used to return the count of each unique column value.

EC2 instance types's exact network performance?

FWIW CloudFront supports streaming as well. Might be better than plain streaming from instances.

Binary Data in JSON String. Something better than Base64

yEnc might work for you:

"yEnc is a binary-to-text encoding scheme for transferring binary files in [text]. It reduces the overhead over previous US-ASCII-based encoding methods by using an 8-bit Extended ASCII encoding method. yEnc's overhead is often (if each byte value appears approximately with the same frequency on average) as little as 1–2%, compared to 33%–40% overhead for 6-bit encoding methods like uuencode and Base64. ... By 2003 yEnc became the de facto standard encoding system for binary files on Usenet."

However, yEnc is an 8-bit encoding, so storing it in a JSON string has the same problems as storing the original binary data — doing it the naïve way means about a 100% expansion, which is worse than base64.

What's the best way to add a full screen background image in React Native

I solved my background image issue using this code.

import React from 'react';
import { StyleSheet, Text, View,Alert,ImageBackground } from 'react-native';

import { TextInput,Button,IconButton,Colors,Avatar } from 'react-native-paper';

class SignInScreen extends React.Component {

    state = {
       UsernameOrEmail  : '',
       Password : '',
    render() {
      return (
             <ImageBackground  source={require('../assets/icons/background3.jpg')} style {styles.backgroundImage}>
              <Text>React Native App</Text>

    export default SignInScreen;

    const styles = StyleSheet.create({
     backgroundImage: {
      flex: 1,
      resizeMode: 'cover', // or 'stretch'

Add placeholder text inside UITextView in Swift?

No need to add any third party library. Just use below code...

class SubmitReviewVC : UIViewController, UITextViewDelegate {

@IBOutlet var txtMessage : UITextView!
var lblPlaceHolder : UILabel!

override func viewDidLoad() {

    txtMessage.delegate = self
    lblPlaceHolder = UILabel()
    lblPlaceHolder.text = "Enter message..."
    lblPlaceHolder.font = UIFont.systemFont(ofSize: txtMessage.font!.pointSize)
    lblPlaceHolder.frame.origin = CGPoint(x: 5, y: (txtMessage.font?.pointSize)! / 2)
    lblPlaceHolder.textColor = UIColor.lightGray
    lblPlaceHolder.isHidden = !txtMessage.text.isEmpty

func textViewDidChange(_ textView: UITextView) {
    lblPlaceHolder.isHidden = !textView.text.isEmpty


Concatenate two string literals

Your second example does not work because there is no operator + for two string literals. Note that a string literal is not of type string, but instead is of type const char *. Your second example will work if you revise it like this:

const string message = string("Hello") + ",world" + exclam;

Finding the max/min value in an array of primitives using Java

    int[] arr = {1, 2, 3};

    List<Integer> list =;
    int max_ = Collections.max(list);
    int i;
    if (max_ > 0) {
        for (i = 1; i < Collections.max(list); i++) {
            if (!list.contains(i)) {
    } else {

Uploading both data and files in one form using Ajax?

For me, it didn't work without enctype: 'multipart/form-data' field in the Ajax request. I hope it helps someone who is stuck in a similar problem.

Even though the enctype was already set in the form attribute, for some reason, the Ajax request didn't automatically identify the enctype without explicit declaration (jQuery 3.3.1).

// Tested, this works for me (jQuery 3.3.1)

fileUploadForm.submit(function (e) {   
            type: 'POST',
            url: $(this).attr('action'),
            enctype: 'multipart/form-data',
            data: new FormData(this),
            processData: false,
            contentType: false,
            success: function (data) {
                console.log('Thank God it worked!');

// enctype field was set in the form but Ajax request didn't set it by default.

<form action="process/file-upload" enctype="multipart/form-data" method="post" >

     <input type="file" name="input-file" accept="text/plain" required> 

As others mentioned above, please also pay special attention to the contentType and processData fields.

How to align 3 divs (left/center/right) inside another div?

There are several tricks available for aligning the elements.

01. Using Table Trick

<div class="container">_x000D_
  <div class="left">_x000D_
  <div class="center">_x000D_
  <div class="right">_x000D_

02. Using Flex Trick

  justify-content: center;_x000D_
  align-items: center;_x000D_
<div class="container">_x000D_
  <div class="left">_x000D_
  <div class="center">_x000D_
  <div class="right">_x000D_

03. Using Float Trick

<div class="container">_x000D_
  <div class="left">_x000D_
  <div class="center">_x000D_
  <div class="right">_x000D_

onclick open window and specific size

Just add them to the parameter string.,'targetWindow','toolbar=no,location=no,status=no,menubar=no,scrollbars=yes,resizable=yes,width=350,height=250')

Copy data from another Workbook through VBA

There's very little reason not to open multiple workbooks in Excel. Key lines of code are:

Application.EnableEvents = False
Application.ScreenUpdating = False

...then you won't see anything whilst the code runs, and no code will run that is associated with the opening of the second workbook. Then there are...

Application.DisplayAlerts = False
Application.Calculation = xlManual as to stop you getting pop-up messages associated with the content of the second file, and to avoid any slow re-calculations. Ensure you set back to True/xlAutomatic at end of your programming

If opening the second workbook is not going to cause performance issues, you may as well do it. In fact, having the second workbook open will make it very beneficial when attempting to debug your code if some of the secondary files do not conform to the expected format

Here is some expert guidance on using multiple Excel files that gives an overview of the different methods available for referencing data

An extension question would be how to cycle through multiple files contained in the same folder. You can use the Windows folder picker using:

With Application.FileDialog(msoFileDialogFolderPicker)
     If .Selected.Items.Count = 1 the InputFolder = .SelectedItems(1)
End With

FName = VBA.Dir(InputFolder)

Do While FName <> ""
'''Do function here
FName = VBA.Dir()

Hopefully some of the above will be of use

Convert Rows to columns using 'Pivot' in SQL Server

I'm writing an sp that could be useful for this purpose, basically this sp pivot any table and return a new table pivoted or return just the set of data, this is the way to execute it:

Exec dbo.rs_pivot_table @schema=dbo,@table=table_name,@column=column_to_pivot,@agg='sum([column_to_agg]),avg([another_column_to_agg]),',

please note that in the parameter @agg the column names must be with '[' and the parameter must end with a comma ','


Create Procedure [dbo].[rs_pivot_table]
    @schema sysname=dbo,
    @table sysname,
    @column sysname,
    @agg nvarchar(max),
    @sel_cols varchar(max),
    @new_table sysname,
    @add_to_col_name sysname=null
--Exec dbo.rs_pivot_table dbo,##TEMPORAL1,tip_liq,'sum([val_liq]),sum([can_liq]),','cod_emp,cod_con,tip_liq',##TEMPORAL1PVT,'hola';

    Declare @query varchar(max)='';
    Declare @aggDet varchar(100);
    Declare @opp_agg varchar(5);
    Declare @col_agg varchar(100);
    Declare @pivot_col sysname;
    Declare @query_col_pvt varchar(max)='';
    Declare @full_query_pivot varchar(max)='';
    Declare @ind_tmpTbl int; --Indicador de tabla temporal 1=tabla temporal global 0=Tabla fisica

    Create Table #pvt_column(
        pivot_col varchar(100)

    Declare @column_agg table(
        opp_agg varchar(5),
        col_agg varchar(100)

    IF  EXISTS (SELECT * FROM sys.objects WHERE object_id = OBJECT_ID(@table) AND type in (N'U'))
        Set @ind_tmpTbl=0;
    ELSE IF OBJECT_ID('tempdb..'+ltrim(rtrim(@table))) IS NOT NULL
        Set @ind_tmpTbl=1;

    IF  EXISTS (SELECT * FROM sys.objects WHERE object_id = OBJECT_ID(@new_table) AND type in (N'U')) OR 
        OBJECT_ID('tempdb..'+ltrim(rtrim(@new_table))) IS NOT NULL
        Set @query='DROP TABLE '+@new_table+'';
        Exec (@query);

    Select @query='Select distinct '+@column+' From '+(case when @ind_tmpTbl=1 then 'tempdb.' else '' end)+@schema+'.'+@table+' where '+@column+' is not null;';
    Print @query;

    Insert into #pvt_column(pivot_col)
    Exec (@query)

    While charindex(',',@agg,1)>0
        Select @aggDet=Substring(@agg,1,charindex(',',@agg,1)-1);

        Insert Into @column_agg(opp_agg,col_agg)

        Set @agg=Substring(@agg,charindex(',',@agg,1)+1,len(@agg))


    Declare cur_agg cursor read_only forward_only local static for
    from @column_agg;

    Open cur_agg;

    Fetch Next From cur_agg
    Into @opp_agg,@col_agg;

    While @@fetch_status=0

        Declare cur_col cursor read_only forward_only local static for
        From #pvt_column;

        Open cur_col;

        Fetch Next From cur_col
        Into @pivot_col;

        While @@fetch_status=0

            Select @query_col_pvt='isnull('+@opp_agg+'(case when '+@column+'='+quotename(@pivot_col,char(39))+' then '+@col_agg+
            ' else null end),0) as ['+lower(Replace(Replace(@opp_agg+'_'+convert(varchar(100),@pivot_col)+'_'+replace(replace(@col_agg,'[',''),']',''),' ',''),'&',''))+
                (case when @add_to_col_name is null then space(0) else '_'+isnull(ltrim(rtrim(@add_to_col_name)),'') end)+']'
            print @query_col_pvt
            Select @full_query_pivot=@full_query_pivot+@query_col_pvt+', '

            --print @full_query_pivot

            Fetch Next From cur_col
            Into @pivot_col;        


        Close cur_col;
        Deallocate cur_col;

        Fetch Next From cur_agg
        Into @opp_agg,@col_agg; 

    Close cur_agg;
    Deallocate cur_agg;

    Select @full_query_pivot=substring(@full_query_pivot,1,len(@full_query_pivot)-1);

    Select @query='Select '+@sel_cols+','+@full_query_pivot+' into '+@new_table+' From '+(case when @ind_tmpTbl=1 then 'tempdb.' else '' end)+
    @schema+'.'+@table+' Group by '+@sel_cols+';';

    print @query;
    Exec (@query);


This is an example of execution:

Exec dbo.rs_pivot_table @schema=dbo,@table=##TEMPORAL1,@column=tip_liq,@agg='sum([val_liq]),avg([can_liq]),',@sel_cols='cod_emp,cod_con,tip_liq',@new_table=##TEMPORAL1PVT;

then Select * From ##TEMPORAL1PVT would return:

enter image description here

Is #pragma once a safe include guard?

Additional note to the people thinking that an automatic one-time-only inclusion of header files is always desired: I build code generators using double or multiple inclusion of header files since decades. Especially for generation of protocol library stubs I find it very comfortable to have a extremely portable and powerful code generator with no additional tools and languages. I'm not the only developer using this scheme as this blogs X-Macros show. This wouldn't be possible to do without the missing automatic guarding.

How to use a table type in a SELECT FROM statement?

Thanks for all help at this issue. I'll post here my solution:

Package Header

  TYPE exch_row IS RECORD(
    currency_cd VARCHAR2(9),
    exch_rt_eur NUMBER,
    exch_rt_usd NUMBER);
  TYPE exch_tbl IS TABLE OF X.exch_row;

  FUNCTION GetExchangeRate RETURN X.exch_tbl PIPELINED;

Package Body

  FUNCTION GetExchangeRate RETURN X.exch_tbl
    exch_rt_usd NUMBER := 1.0; --todo
    rw exch_row;

    FOR rw IN (SELECT c.currency_cd AS currency_cd, e.exch_rt AS exch_rt_eur, (e.exch_rt / exch_rt_usd) AS exch_rt_usd
                 FROM exch e, currency c
                WHERE c.currency_key = e.currency_key
                  ) LOOP
      PIPE ROW(rw);

      CURSOR c0 IS
        SELECT i.DOC,
               i.net_value / rt.exch_rt_usd AS net_value_in_usd,
               i.net_value / rt.exch_rt_eur AS net_value_in_euro,
          FROM item i, (SELECT * FROM TABLE(X.GetExchangeRate())) rt
         WHERE i.doc_currency = rt.currency_cd;

      TYPE c0_type IS TABLE OF c0%ROWTYPE;

      items c0_type;
      OPEN c0;

          INTO items LIMIT batchsize;

        EXIT WHEN items.COUNT = 0;
          INSERT INTO detail_items VALUES items (i);

      END LOOP;

      CLOSE c0;




Please review.

How to check type of files without extensions in python?

In the case of images, you can use the imghdr module.

>>> import imghdr
>>> imghdr.what('8e5d7e9d873e2a9db0e31f9dfc11cf47')  # You can pass a file name or a file object as first param. See doc for optional 2nd param.

Python 2 imghdr doc
Python 3 imghdr doc

Laravel: Using try...catch with DB::transaction()

You could wrapping the transaction over try..catch or even reverse them, here my example code I used to in laravel 5,, if you look deep inside DB:transaction() in Illuminate\Database\Connection that the same like you write manual transaction.

Laravel Transaction

public function transaction(Closure $callback)

        try {
            $result = $callback($this);


        catch (Exception $e) {

            throw $e;
        } catch (Throwable $e) {

            throw $e;

        return $result;

so you could write your code like this, and handle your exception like throw message back into your form via flash or redirect to another page. REMEMBER return inside closure is returned in transaction() so if you return redirect()->back() it won't redirect immediately, because the it returned at variable which handle the transaction.

Wrap Transaction

$result = DB::transaction(function () use ($request, $message) {

      // execute query 1
      // execute query 2
      // ..

      return redirect(route('account.article'));

   } catch (\Exception $e) {
       return redirect()->back()->withErrors(['error' => $e->getMessage()]);

// redirect the page
return $result;

then the alternative is throw boolean variable and handle redirect outside transaction function or if your need to retrieve why transaction failed you can get it from $e->getMessage() inside catch(Exception $e){...}

Transmitting newline character "\n"

late to the party, but if anyone comes across this, javascript has a encodeURI method

Use <Image> with a local file

I was having trouble with react-native-navigation, I created my own header component, then inserted a image - as logo - on the left before title, then when I was triggering navigate to another screen and then back again, logo was loading again, with a timeout near 1s, my file were local. My solution :


{"file" : "base64 big string"}


import Logo from '.../Logo.json'
<Image source:{{uri:Logo.file}} />

Why does typeof array with objects return "object" and not "array"?

Quoting the spec

15.4 Array Objects

Array objects give special treatment to a certain class of property names. A property name P (in the form of a String value) is an array index if and only if ToString(ToUint32(P)) is equal to P and ToUint32(P) is not equal to 2^32-1. A property whose property name is an array index is also called an element. Every Array object has a length property whose value is always a nonnegative integer less than 2^32. The value of the length property is numerically greater than the name of every property whose name is an array index; whenever a property of an Array object is created or changed, other properties are adjusted as necessary to maintain this invariant. Specifically, whenever a property is added whose name is an array index, the length property is changed, if necessary, to be one more than the numeric value of that array index; and whenever the length property is changed, every property whose name is an array index whose value is not smaller than the new length is automatically deleted. This constraint applies only to own properties of an Array object and is unaffected by length or array index properties that may be inherited from its prototypes.

And here's a table for typeof

enter image description here

To add some background, there are two data types in JavaScript:

  1. Primitive Data types - This includes null, undefined, string, boolean, number and object.
  2. Derived data types/Special Objects - These include functions, arrays and regular expressions. And yes, these are all derived from "Object" in JavaScript.

An object in JavaScript is similar in structure to the associative array/dictionary seen in most object oriented languages - i.e., it has a set of key-value pairs.

An array can be considered to be an object with the following properties/keys:

  1. Length - This can be 0 or above (non-negative).
  2. The array indices. By this, I mean "0", "1", "2", etc are all properties of array object.

Hope this helped shed more light on why typeof Array returns an object. Cheers!

How a thread should close itself in Java?

If you simply call interrupt(), the thread will not automatically be closed. Instead, the Thread might even continue living, if isInterrupted() is implemented accordingly. The only way to guaranteedly close a thread, as asked for by OP, is


Method is deprecated, however.

Calling return only returns from the current method. This only terminates the thread if you're at its top level.

Nevertheless, you should work with interrupt() and build your code around it.

How to enable cross-origin resource sharing (CORS) in the express.js framework on node.js

Recommend using the cors express module. This allows you to whitelist domains, allow/restrict domains specifically to routes, etc.,

Why do we use Base64?

Why not look to the RFC that currently defines Base64?

Base encoding of data is used in many situations to store or transfer
data in environments that, perhaps for legacy reasons, are restricted to US-ASCII [1] data.Base encoding can also be used in new applications that do not have legacy restrictions, simply because it makes it possible to manipulate objects with text editors.

In the past, different applications have had different requirements and thus sometimes implemented base encodings in slightly different ways. Today, protocol specifications sometimes use base encodings in general, and "base64" in particular, without a precise description or reference. Multipurpose Internet Mail Extensions (MIME) [4] is often used as a reference for base64 without considering the consequences for line-wrapping or non-alphabet characters. The purpose of this specification is to establish common alphabet and encoding considerations. This will hopefully reduce ambiguity in other documents, leading to better interoperability.

Base64 was originally devised as a way to allow binary data to be attached to emails as a part of the Multipurpose Internet Mail Extensions.

Formatting html email for Outlook

I used VML(Vector Markup Language) based formatting in my email template. In VML Based you have write your code within comment I took help from this site.

Explode PHP string by new line

First of all, I think it's usually \r\n, second of all, those are not the same on all systems. That will only work on windows. It's kind-of annoying trying to figure out how to replace new lines because different systems treat them differently (see here). You might have better luck with just \n.

How to remove empty lines with or without whitespace in Python

you can simply use rstrip:

    for stuff in largestring:

Easily measure elapsed time

They are they same because your doSomething function happens faster than the granularity of the timer. Try:

printf ("**MyProgram::before time= %ld\n", time(NULL));

for(i = 0; i < 1000; ++i) {

printf ("**MyProgram::after time= %ld\n", time(NULL));

MySQL and PHP - insert NULL rather than empty string

To pass a NULL to MySQL, you do just that.

INSERT INTO table (field,field2) VALUES (NULL,3)

So, in your code, check if $intLat, $intLng are empty, if they are, use NULL instead of '$intLat' or '$intLng'.

$intLat = !empty($intLat) ? "'$intLat'" : "NULL";
$intLng = !empty($intLng) ? "'$intLng'" : "NULL";

$query = "INSERT INTO data (notes, id, filesUploaded, lat, lng, intLat, intLng)
          VALUES ('$notes', '$id', TRIM('$imageUploaded'), '$lat', '$long', 
                  $intLat, $intLng)";

Command to delete all pods in all kubernetes namespaces

If you already have pods which are recreated, think to delete all deployments first

kubectl delete -n *NAMESPACE deployment *DEPLOYMENT

Just replace the NAMSPACE and the DEPLOYMENT to corresponding ones, you can get all deployments information by the following command

kubectl get deployments --all-namespaces

npm install error - MSB3428: Could not load the Visual C++ component "VCBuild.exe"

I tried the above suggested npm install --global --production windows-build-tools but found that the installation was always hanging forever.

I managed to fix the problem by installing Node.js 8 instead of Node.js 10.

How to fire an event on class change using jQuery?

you can use something like this:



$(otherSelector).bind('ClassChanged', data, function(){//stuff });

but otherwise, no, there's no predefined function to fire an event when a class changes.

Read more about triggers here

Open a workbook using FileDialog and manipulate it in Excel VBA

Thankyou Frank.i got the idea. Here is the working code.

Option Explicit
Private Sub CommandButton1_Click()

  Dim directory As String, fileName As String, sheet As Worksheet, total As Integer
  Dim fd As Office.FileDialog

  Set fd = Application.FileDialog(msoFileDialogFilePicker)

  With fd
    .AllowMultiSelect = False
    .Title = "Please select the file."
    .Filters.Add "Excel 2003", "*.xls?"

    If .Show = True Then
      fileName = Dir(.SelectedItems(1))

    End If
  End With

  Application.ScreenUpdating = False
  Application.DisplayAlerts = False

  Workbooks.Open (fileName)

  For Each sheet In Workbooks(fileName).Worksheets
    total = Workbooks("import-sheets.xlsm").Worksheets.Count
    Workbooks(fileName).Worksheets(sheet.Name).Copy _
  Next sheet


  Application.ScreenUpdating = True
  Application.DisplayAlerts = True

End Sub

How can I list the scheduled jobs running in my database?

I think you need the SCHEDULER_ADMIN role to see the dba_scheduler tables (however this may grant you too may rights)


Delete from a table based on date

or an ORACLE version:

  from table_name
 where trunc( > to_date('01/01/2009','mm/dd/yyyy') 

Conversion failed when converting the varchar value to data type int in sql

Your problem seams to be located here:

SELECT @maxCode = CAST(MAX(CAST(SUBSTRING(Voucher_No,LEN(@startFrom)+1,LEN(Voucher_No)- LEN(@Prefix)) AS INT)) AS varchar(100)) FROM dbo.Journal_Entry;
SET @sCode=CAST(@maxCode AS INT)

As the error says, you're casting a string that contains a letter 'J' to an INT which for obvious reasons is not possible.

Either fix SUBSTRING or don't store the letter 'J' in the database and only prepend it when reading.

What exactly should be set in PYTHONPATH?

You don't have to set either of them. PYTHONPATH can be set to point to additional directories with private libraries in them. If PYTHONHOME is not set, Python defaults to using the directory where python.exe was found, so that dir should be in PATH.

Writing an mp4 video using python opencv

There are some things to change in your code:

  1. Change the name of your output to 'output.mp4' (change to .mp4)
  2. I had the the same issues that people have in the comments, so I changed the fourcc to 0x7634706d: out = cv2.VideoWriter('output.mp4',0x7634706d , 20.0, (640,480))

Getting "Skipping JaCoCo execution due to missing execution data file" upon executing JaCoCo

My response is very late but for others users In your case you have to configure failsafe pluging to use the command line agent configuration saved in itCoverageAgent variable. For exemple


In your maven configuration, jacoco prepare the command line arguments in prepare-agent phase, but failsafe plugin doesn't use it so there is no execution data file.

Android activity life cycle - what are all these methods for?

The entire confusion is caused since Google chose non-intuivitive names instead of something as follows:

onCreateAndPrepareToDisplay()   [instead of onCreate() ]
onPrepareToDisplay()            [instead of onRestart() ]
onVisible()                     [instead of onStart() ]
onBeginInteraction()            [instead of onResume() ]
onPauseInteraction()            [instead of onPause() ]
onInvisible()                   [instead of onStop]
onDestroy()                     [no change] 

The Activity Diagram can be interpreted as:

enter image description here

How to set root password to null

  • connect to mysql as user root (use one of the two following methods)
    • login as root and start mysql using mysql -p, enter current root password
    • login as self and start mysql using mysql -u root -p, enter current root password
  • mysql> set password = password('');

Done! No root password.

How to apply a patch generated with git format-patch?

Note: You can first preview what your patch will do:

First the stats:

git apply --stat a_file.patch

Then a dry run to detect errors:

git apply --check a_file.patch

Finally, you can use git am to apply your patch as a commit. This also allows you to sign off an applied patch.
This can be useful for later reference.

git am --signoff < a_file.patch 

See an example in this article:

In your git log, you’ll find that the commit messages contain a “Signed-off-by” tag. This tag will be read by Github and others to provide useful info about how the commit ended up in the code.


Can you break from a Groovy "each" closure?

No, you can't break from a closure in Groovy without throwing an exception. Also, you shouldn't use exceptions for control flow.

If you find yourself wanting to break out of a closure you should probably first think about why you want to do this and not how to do it. The first thing to consider could be the substitution of the closure in question with one of Groovy's (conceptual) higher order functions. The following example:

for ( i in 1..10) { if (i < 5) println i; else return}


(1..10).each{if (it < 5) println it}


(1..10).findAll{it < 5}.each{println it} 

which also helps clarity. It states the intent of your code much better.

The potential drawback in the shown examples is that iteration only stops early in the first example. If you have performance considerations you might want to stop it right then and there.

However, for most use cases that involve iterations you can usually resort to one of Groovy's find, grep, collect, inject, etc. methods. They usually take some "configuration" and then "know" how to do the iteration for you, so that you can actually avoid imperative looping wherever possible.

Intellij IDEA Java classes not auto compiling on save

The only thing that worked for me in my maven project that was affected by this is to add a "test-compile" goal to the run configuration of my unit tests. Incredibly clumsy solution, but it works.

enter image description here

Docker container not starting (docker start)

What I need is to use Docker with MariaDb on different port /3301/ on my Ubuntu machine because I already had MySql installed and running on 3306.

To do this after half day searching did it using:

docker run -it -d -p 3301:3306 -v ~/mdbdata/mariaDb:/var/lib/mysql -e MYSQL_ROOT_PASSWORD=root --name mariaDb mariadb

This pulls the image with latest MariaDb, creates container called mariaDb, and run mysql on port 3301. All data of which is located in home directory in /mdbdata/mariaDb.

To login in mysql after that can use:

mysql -u root -proot -h -P3301

Used sources are:

The answer of Iarks in this article /using -it -d was the key :) /




Good luck all!

PostgreSQL: How to change PostgreSQL user password?


On many systems, a user's account often contains a period, or some sort of punction (user: john.smith, horise.johnson). IN these cases a modification will have to be made to the accepted answer above. The change requires the username to be double-quoted.


ALTER USER "username.lastname" WITH PASSWORD 'password'; 


Postgres is quite picky on when to use a 'double quote' and when to use a 'single quote'. Typically when providing a string you would use a single quote.

Pandas rename column by position?

You can do this:

df.rename(columns={ df.columns[1]: "whatever" })

What does 'IISReset' do?

Editing the web.config file or updating a DLL in the bin folder just recycles the worker process for that application, not the whole pool.

How to convert char to int?

You may use the following extension method:

public static class CharExtensions
        public static int CharToInt(this char c)
            if (c < '0' || c > '9')
                throw new ArgumentException("The character should be a number", "c");

            return c - '0';

Best practices for API versioning?

This is a good and a tricky question. The topic of URI design is at the same time the most prominent part of a REST API and, therefore, a potentially long-term commitment towards the users of that API.

Since evolution of an application and, to a lesser extent, its API is a fact of life and that it's even similar to the evolution of a seemingly complex product like a programming language, the URI design should have less natural constraints and it should be preserved over time. The longer the application's and API's lifespan, the greater the commitment to the users of the application and API.

On the other hand, another fact of life is that it is hard to foresee all the resources and their aspects that would be consumed through the API. Luckily, it is not necessary to design the entire API which will be used until Apocalypse. It is sufficient to correctly define all the resource end-points and the addressing scheme of every resource and resource instance.

Over time you may need to add new resources and new attributes to each particular resource, but the method that API users follow to access a particular resources should not change once a resource addressing scheme becomes public and therefore final.

This method applies to HTTP verb semantics (e.g. PUT should always update/replace) and HTTP status codes that are supported in earlier API versions (they should continue to work so that API clients that have worked without human intervention should be able to continue to work like that).

Furthermore, since embedding of API version into the URI would disrupt the concept of hypermedia as the engine of application state (stated in Roy T. Fieldings PhD dissertation) by having a resource address/URI that would change over time, I would conclude that API versions should not be kept in resource URIs for a long time meaning that resource URIs that API users can depend on should be permalinks.

Sure, it is possible to embed API version in base URI but only for reasonable and restricted uses like debugging a API client that works with the the new API version. Such versioned APIs should be time-limited and available to limited groups of API users (like during closed betas) only. Otherwise, you commit yourself where you shouldn't.

A couple of thoughts regarding maintenance of API versions that have expiration date on them. All programming platforms/languages commonly used to implement web services (Java, .NET, PHP, Perl, Rails, etc.) allow easy binding of web service end-point(s) to a base URI. This way it's easy to gather and keep a collection of files/classes/methods separate across different API versions.

From the API users POV, it's also easier to work with and bind to a particular API version when it's this obvious but only for limited time, i.e. during development.

From the API maintainer's POV, it's easier to maintain different API versions in parallel by using source control systems that predominantly work on files as the smallest unit of (source code) versioning.

However, with API versions clearly visible in URI there's a caveat: one might also object this approach since API history becomes visible/aparent in the URI design and therefore is prone to changes over time which goes against the guidelines of REST. I agree!

The way to go around this reasonable objection, is to implement the latest API version under versionless API base URI. In this case, API client developers can choose to either:

  • develop against the latest one (committing themselves to maintain the application protecting it from eventual API changes that might break their badly designed API client).

  • bind to a specific version of the API (which becomes apparent) but only for a limited time

For example, if API v3.0 is the latest API version, the following two should be aliases (i.e. behave identically to all API requests):


In addition, API clients that still try to point to the old API should be informed to use the latest previous API version, if the API version they're using is obsolete or not supported anymore. So accessing any of the obsolete URIs like these:


should return any of the 30x HTTP status codes that indicate redirection that are used in conjunction with Location HTTP header that redirects to the appropriate version of resource URI which remain to be this one:


There are at least two redirection HTTP status codes that are appropriate for API versioning scenarios:

  • 301 Moved permanently indicating that the resource with a requested URI is moved permanently to another URI (which should be a resource instance permalink that does not contain API version info). This status code can be used to indicate an obsolete/unsupported API version, informing API client that a versioned resource URI been replaced by a resource permalink.

  • 302 Found indicating that the requested resource temporarily is located at another location, while requested URI may still supported. This status code may be useful when the version-less URIs are temporarily unavailable and that a request should be repeated using the redirection address (e.g. pointing to the URI with APi version embedded) and we want to tell clients to keep using it (i.e. the permalinks).

  • other scenarios can be found in Redirection 3xx chapter of HTTP 1.1 specification

Batch program to to check if process exists

TASKLIST doesn't set an exit code that you could check in a batch file. One workaround to checking the exit code could be parsing its standard output (which you are presently redirecting to NUL). Apparently, if the process is found, TASKLIST will display its details, which include the image name too. Therefore, you could just use FIND or FINDSTR to check if the TASKLIST's output contains the name you have specified in the request. Both FIND and FINDSTR set a non-null exit code if the search was unsuccessful. So, this would work:

@echo off
tasklist /fi "imagename eq notepad.exe" | find /i "notepad.exe" > nul
if not errorlevel 1 (taskkill /f /im "notepad.exe") else (
  specific commands to perform if the process was not found

There's also an alternative that doesn't involve TASKLIST at all. Unlike TASKLIST, TASKKILL does set an exit code. In particular, if it couldn't terminate a process because it simply didn't exist, it would set the exit code of 128. You could check for that code to perform your specific actions that you might need to perform in case the specified process didn't exist:

@echo off
taskkill /f /im "notepad.exe" > nul
if errorlevel 128 (
  specific commands to perform if the process
  was not terminated because it was not found

What is the scope of variables in JavaScript?

Variables declared globally have a global scope. Variables declared within a function are scoped to that function, and shadow global variables of the same name.

(I'm sure there are many subtleties that real JavaScript programmers will be able to point out in other answers. In particular I came across this page about what exactly this means at any time. Hopefully this more introductory link is enough to get you started though.)

String, StringBuffer, and StringBuilder

                  String                    StringBuffer         StringBuilder
Storage Area | Constant String Pool         Heap                   Heap 
Modifiable   |  No (immutable)              Yes( mutable )         Yes( mutable )
Thread Safe  |      Yes                     Yes                     No
 Performance |     Fast                 Very slow                  Fast

Java 256-bit AES Password-Based Encryption

Consider using the Spring Security Crypto Module

The Spring Security Crypto module provides support for symmetric encryption, key generation, and password encoding. The code is distributed as part of the core module but has no dependencies on any other Spring Security (or Spring) code.

It's provides a simple abstraction for encryption and seems to match what's required here,

The "standard" encryption method is 256-bit AES using PKCS #5's PBKDF2 (Password-Based Key Derivation Function #2). This method requires Java 6. The password used to generate the SecretKey should be kept in a secure place and not be shared. The salt is used to prevent dictionary attacks against the key in the event your encrypted data is compromised. A 16-byte random initialization vector is also applied so each encrypted message is unique.

A look at the internals reveals a structure similar to erickson's answer.

As noted in the question, this also requires the Java Cryptography Extension (JCE) Unlimited Strength Jurisdiction Policy (else you'll encounter InvalidKeyException: Illegal Key Size). It's downloadable for Java 6, Java 7 and Java 8.

Example usage


public class CryptoExample {
    public static void main(String[] args) {
        final String password = "I AM SHERLOCKED";  
        final String salt = KeyGenerators.string().generateKey();
        TextEncryptor encryptor = Encryptors.text(password, salt);      
        System.out.println("Salt: \"" + salt + "\"");
        String textToEncrypt = "*royal secrets*";
        System.out.println("Original text: \"" + textToEncrypt + "\"");
        String encryptedText = encryptor.encrypt(textToEncrypt);
        System.out.println("Encrypted text: \"" + encryptedText + "\"");
        // Could reuse encryptor but wanted to show reconstructing TextEncryptor
        TextEncryptor decryptor = Encryptors.text(password, salt);
        String decryptedText = decryptor.decrypt(encryptedText);
        System.out.println("Decrypted text: \"" + decryptedText + "\"");
        if(textToEncrypt.equals(decryptedText)) {
            System.out.println("Success: decrypted text matches");
        } else {
            System.out.println("Failed: decrypted text does not match");

And sample output,

Salt: "feacbc02a3a697b0"
Original text: "*royal secrets*"
Encrypted text: "7c73c5a83fa580b5d6f8208768adc931ef3123291ac8bc335a1277a39d256d9a" 
Decrypted text: "*royal secrets*"
Success: decrypted text matches target _self v window.location.href?

window.location.href = "webpage.htm";

TypeError: 'in <string>' requires string as left operand, not int

You simply need to make cab a string:

cab = '6176'

As the error message states, you cannot do <int> in <string>:

>>> 1 in '123'
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: 'in <string>' requires string as left operand, not int

because integers and strings are two totally different things and Python does not embrace implicit type conversion ("Explicit is better than implicit.").

In fact, Python only allows you to use the in operator with a right operand of type string if the left operand is also of type string:

>>> '1' in '123'  # Works!
>>> [] in '123'
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: 'in <string>' requires string as left operand, not list
>>> 1.0 in '123'
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: 'in <string>' requires string as left operand, not float
>>> {} in '123'
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: 'in <string>' requires string as left operand, not dict

Get selected option text with JavaScript

Try options

function myNewFunction(sel) {_x000D_
<select id="box1" onChange="myNewFunction(this);">_x000D_
  <option value="98">dog</option>_x000D_
  <option value="7122">cat</option>_x000D_
  <option value="142">bird</option>_x000D_

What are the sizes used for the iOS application splash screen?

For Adobe AIR iOS Developers, take note that if your iPad Splash images "shift" or display and scale a second later, it's because there are different dimensions depending on what version of AIR you're using.

768 x 1004 (AIR 3.3 and earlier)
768 x 1024 (AIR 3.4 and higher)

[email protected]:
1536 x 2008 (AIR 3.3 and earlier)
1536 x 2048 (AIR 3.4 and higher)


AngularJS - get element attributes values

Use Jquery functions

<Button id="myPselector" data-id="1234">HI</Button> 

Change image in HTML page every few seconds

You can load the images at the beginning and change the css attributes to show every image.

var images = array();
for( url in your_urls_array ){
   var img = document.createElement( "img" );
   //here the image attributes ( width, height, position, etc )
   images.push( img );

function player( position )
  images[position-1].style.display = "none" //be careful working with the first position
  images[position].style.display = "block";
  //reset position if needed
  timer = setTimeOut( "player( position )", time );

How get total sum from input box values using Javascript?


window.sumInputs = function() {
    var inputs = document.getElementsByTagName('input'),
        result = document.getElementById('total'),
        sum = 0;            

    for(var i=0; i<inputs.length; i++) {
        var ip = inputs[i];

        if ( &&"total") < 0) {
            sum += parseInt(ip.value) || 0;


    result.value = sum;


Qty1 : <input type="text" name="qty1" id="qty"/><br>
Qty2 : <input type="text" name="qty2" id="qty"/><br>
Qty3 : <input type="text" name="qty3" id="qty"/><br>
Qty4 : <input type="text" name="qty4" id="qty"/><br>
Qty5 : <input type="text" name="qty5" id="qty"/><br>
Qty6 : <input type="text" name="qty6" id="qty"/><br
Qty7 : <input type="text" name="qty7" id="qty"/><br>
Qty8 : <input type="text" name="qty8" id="qty"/><br>
Total : <input type="text" name="total" id="total"/>

<a href="javascript:sumInputs()">Sum</a>



C# Numeric Only TextBox Control


// Boolean flag used to determine when a character other than a number is entered.
private bool nonNumberEntered = false;
// Handle the KeyDown event to determine the type of character entered into the control.
private void textBox1_KeyDown(object sender, KeyEventArgs e)
    // Initialize the flag to false.
    nonNumberEntered = false;
    // Determine whether the keystroke is a number from the top of the keyboard.
    if (e.KeyCode < Keys.D0 || e.KeyCode > Keys.D9)
        // Determine whether the keystroke is a number from the keypad.
        if (e.KeyCode < Keys.NumPad0 || e.KeyCode > Keys.NumPad9)
            // Determine whether the keystroke is a backspace.
            if (e.KeyCode != Keys.Back)
                // A non-numerical keystroke was pressed.
                // Set the flag to true and evaluate in KeyPress event.
                nonNumberEntered = true;

private void textBox1_KeyPress(object sender, KeyPressEventArgs e)
    if (nonNumberEntered == true)
       MessageBox.Show("Please enter number only..."); 
       e.Handled = true;

Source is

"The POM for ... is missing, no dependency information available" even though it exists in Maven Repository

This is my solution, may be it can helps I use IntelliJ IDE. File -> Setting -> Maven -> Importing change JDK for importer to 1.8( you can change to lower, higher)

How to get equal width of input and select fields

Add this code in css:

 select, input[type="text"]{

Write output to a text file in PowerShell

Use the Out-File cmdlet

 Compare-Object ... | Out-File C:\filename.txt

Optionally, add -Encoding utf8 to Out-File as the default encoding is not really ideal for many uses.

Setting max width for body using Bootstrap

I don't know if this was pointed out here. The settings for .container width have to be set on the Bootstrap website. I personally did not have to edit or touch anything within CSS files to tune my .container size which is 1600px. Under Customize tab, there are three sections responsible for media and the responsiveness of the web:

  • Media queries breakpoints
  • Grid system
  • Container sizes

Besides Media queries breakpoints, which I believe most people refer to, I've also changed @container-desktop to (1130px + @grid-gutter-width) and @container-large-desktop to (1530px + @grid-gutter-width). Now, the .container changes its width if my browser is scaled up to ~1600px and ~1200px. Hope it can help.

Why does this iterative list-growing code give IndexError: list assignment index out of range?

One more way:

for k in range(1,len(i)):
    j = numpy.vstack([j,i[k]])

In this case j will be a numpy array

How can I combine two HashMap objects containing the same types?

If you know you don't have duplicate keys, or you want values in map2 to overwrite values from map1 for duplicate keys, you can just write

map3 = new HashMap<>(map1);

If you need more control over how values are combined, you can use Map.merge, added in Java 8, which uses a user-provided BiFunction to merge values for duplicate keys. merge operates on individual keys and values, so you'll need to use a loop or Map.forEach. Here we concatenate strings for duplicate keys:

map3 = new HashMap<>(map1);
for (Map.Entry<String, String> e : map2.entrySet())
    map3.merge(e.getKey(), e.getValue(), String::concat);
//or instead of the above loop
map2.forEach((k, v) -> map3.merge(k, v, String::concat));

If you know you don't have duplicate keys and want to enforce it, you can use a merge function that throws an AssertionError:

map2.forEach((k, v) ->
    map3.merge(k, v, (v1, v2) ->
        {throw new AssertionError("duplicate values for key: "+k);}));

Taking a step back from this specific question, the Java 8 streams library provides toMap and groupingBy Collectors. If you're repeatedly merging maps in a loop, you may be able to restructure your computation to use streams, which can both clarify your code and enable easy parallelism using a parallel stream and concurrent collector.

How to debug a stored procedure in Toad?

Basic Steps to Debug a Procedure in Toad

  1. Load your Procedure in Toad Editor.
  2. Put debug point on the line where you want to debug.See the first screenshot.
  3. Right click on the editor Execute->Execute PLSQL(Debugger).See the second screeshot.
  4. A window opens up,you need to select the procedure from the left side and pass parameters for that procedure and then click Execute.See the third screenshot.
  5. Now start your debugging check Debug-->Step Over...Add Watch etc.

Reference:Toad Debugger


Execute In Debug


What Language is Used To Develop Using Unity

Unity supports:
1. UnityScript(Is known as Javascript but includes more functionality for the Unity game engine. I think this could be very easy to learn)
2. Boo (No experience)
3. C# (I prefer this as it is useful to learn and you will be able to use this outside of unity as well. I also think it is easy to get used to)

jQuery.css() - marginLeft vs. margin-left?

Hi i tried this it is working.


Remove a marker from a GoogleMap

to clear all scribbles in the map use


Can not get a simple bootstrap modal to work

I run into this issue too. I was including bootstrap.js AND bootstrap-modal.js. If you already have bootstrap.js, you don't need to include popover.

How to suppress binary file matching results in grep

There are three options, that you can use. -I is to exclude binary files in grep. Other are for line numbers and file names.

grep -I -n -H 

-I -- process a binary file as if it did not contain matching data; 
-n -- prefix each line of output with the 1-based line number within its input file
-H -- print the file name for each match

So this might be a way to run grep:

grep -InH your-word *

Focus Next Element In Tab Index

Did you specify your own tabIndex values for each element you want to cycle through? if so, you can try this:

var lasTabIndex = 10; //Set this to the highest tabIndex you have
function OnFocusOut()
    var currentElement = $get(currentElementId); // ID set by OnFocusIn 

    var curIndex = $(currentElement).attr('tabindex'); //get the tab index of the current element
    if(curIndex == lastTabIndex) { //if we are on the last tabindex, go back to the beginning
        curIndex = 0;
    $('[tabindex=' + (curIndex + 1) + ']').focus(); //set focus on the element that has a tab index one greater than the current tab index

You are using jquery, right?

How to insert text into the textarea at the current cursor position?

Rab's answer works great, but not for Microsoft Edge, so I added a small adaptation for Edge as well:

function insertAtCursor(myField, myValue) {
    //IE support
    if (document.selection) {
        sel = document.selection.createRange();
        sel.text = myValue;
    // Microsoft Edge
    else if(window.navigator.userAgent.indexOf("Edge") > -1) {
      var startPos = myField.selectionStart; 
      var endPos = myField.selectionEnd; 

      myField.value = myField.value.substring(0, startPos)+ myValue 
             + myField.value.substring(endPos, myField.value.length); 

      var pos = startPos + myValue.length;
      myField.setSelectionRange(pos, pos);
    //MOZILLA and others
    else if (myField.selectionStart || myField.selectionStart == '0') {
        var startPos = myField.selectionStart;
        var endPos = myField.selectionEnd;
        myField.value = myField.value.substring(0, startPos)
            + myValue
            + myField.value.substring(endPos, myField.value.length);
    } else {
        myField.value += myValue;

Draggable div without jQuery UI

What I saw above is complicate.....

Here is some code can refer to.

                  dragging = true;
                  dragX = e.clientX - $(this).position().left;
                  //To calculate the distance between the cursor pointer and box 
                  dragY = e.clientY - $(this).position().top;
                mouseup:function(){dragging = false;},
                  //If not set this on/off,the move will continue forever


dragging,dragX,dragY may place as the global variable.

It's a simple show about this issue,but there is some bug about this method.

If it's your need now,here's the Example here.

How to start and stop android service from a adb shell?

Responding to pzulw's feedback to sandroid about specifying the intent.

The format of the component name is described in the api docs for ComponentName.unflattenFromString

It splits the string at the first '/', taking the part before as the package name and the part after as the class name. As a special convenience (to use, for example, when parsing component names on the command line), if the '/' is immediately followed by a '.' then the final class name will be the concatenation of the package name with the string following the '/'. Thus "" becomes package="" class="".

How to break out of the IF statement

You can return only if !something2 or use else return:

public void Method()
        //some code
            //now I should break from ifs and go to te code outside ifs
        if(!something2) // or else
    // The code i want to go if the second if is true

Merge two dataframes by index

Use merge, which is inner join by default:

pd.merge(df1, df2, left_index=True, right_index=True)

Or join, which is left join by default:


Or concat, which is outer join by default:

pd.concat([df1, df2], axis=1)


df1 = pd.DataFrame({'a':range(6),
                    'b':[5,3,6,9,2,4]}, index=list('abcdef'))

print (df1)
   a  b
a  0  5
b  1  3
c  2  6
d  3  9
e  4  2
f  5  4

df2 = pd.DataFrame({'c':range(4),
                    'd':[10,20,30, 40]}, index=list('abhi'))

print (df2)
   c   d
a  0  10
b  1  20
h  2  30
i  3  40

#default inner join
df3 = pd.merge(df1, df2, left_index=True, right_index=True)
print (df3)
   a  b  c   d
a  0  5  0  10
b  1  3  1  20

#default left join
df4 = df1.join(df2)
print (df4)
   a  b    c     d
a  0  5  0.0  10.0
b  1  3  1.0  20.0
c  2  6  NaN   NaN
d  3  9  NaN   NaN
e  4  2  NaN   NaN
f  5  4  NaN   NaN

#default outer join
df5 = pd.concat([df1, df2], axis=1)
print (df5)
     a    b    c     d
a  0.0  5.0  0.0  10.0
b  1.0  3.0  1.0  20.0
c  2.0  6.0  NaN   NaN
d  3.0  9.0  NaN   NaN
e  4.0  2.0  NaN   NaN
f  5.0  4.0  NaN   NaN
h  NaN  NaN  2.0  30.0
i  NaN  NaN  3.0  40.0

Validating parameters to a Bash script

Old post but I figured i could contribute anyway.

A script is arguably not necessary and with some tolerance to wild cards could be carried out from the command line.

  1. wild anywhere matching. Lets remove any occurrence of sub "folder"

    $ rm -rf ~/*/folder/*
  2. Shell iterated. Lets remove the specific pre and post folders with one line

    $ rm -rf ~/foo{1,2,3}/folder/{ab,cd,ef}
  3. Shell iterated + var (BASH tested).

    $ var=bar rm -rf ~/foo{1,2,3}/${var}/{ab,cd,ef}

How to change the Push and Pop animations in a navigation based app

Using private calls is a bad idea as Apple no longer approve apps that do that. Maybe you could try this:

//Init Animation
[UIView beginAnimations:nil context:NULL];
[UIView setAnimationDuration: 0.50];

[UIView setAnimationTransition:UIViewAnimationTransitionCurlUp forView:self.navigationController.view cache:YES];

//Create ViewController
MyViewController *myVC = [[MyViewController alloc] initWith...];

[self.navigationController pushViewController:myVC animated:NO];
[myVC release];

//Start Animation
[UIView commitAnimations];

Check if string is in a pandas dataframe

You should check the value of your line of code like adding checking length of it.

    print("Name Present")

The OLE DB provider "Microsoft.ACE.OLEDB.12.0" for linked server "(null)"

  1. Close SQL Server Management Studio. Type Services.msc in the run command to open the services window.

  2. Search for SQL Server Service and right click it and select properties.

  3. In the Log On Tab, select system account/or select your domain ID and Account and password.

  4. Once it finds your login name press OK.

  5. Now type your login’s passwords in both the fields.

  6. Restart the services so that the new changes are applied as shown in figure below.

  7. Now start SQL Server Management Studio and try to run the query if still not working try a system restart.

... or execute the following query:

USE [master] 
EXEC master.dbo.sp_MSset_oledb_prop N'Microsoft.ACE.OLEDB.12.0', N'AllowInProcess', 1 
EXEC master.dbo.sp_MSset_oledb_prop N'Microsoft.ACE.OLEDB.12.0', N'DynamicParameters', 1 

Java: Convert a String (representing an IP) to InetAddress

Simply call InetAddress.getByName(String host) passing in your textual IP address.

From the javadoc: The host name can either be a machine name, such as "", or a textual representation of its IP address.

InetAddress javadoc

Change values of select box of "show 10 entries" of jquery datatable

$(document).ready(function() {
    $('#example').dataTable( {
    "aLengthMenu": [[25, 50, 75, -1], [25, 50, 75, "All"]],
    "pageLength": 25
    } );
} );

aLengthMenu : This parameter allows you to readily specify the entries in the length drop down menu that DataTables shows when pagination is enabled. It can be either a 1D array of options which will be used for both the displayed option and the value, or a 2D array which will use the array in the first position as the value, and the array in the second position as the displayed options (useful for language strings such as 'All').


Since DataTables v1.10, the options you are looking for are pageLength and lengthMenu

SQL Server SELECT INTO @variable?

If you wanted to simply assign some variables for later use, you can do them in one shot with something along these lines:

declare @var1 int,@var2 int,@var3 int;

    @var1 = field1,
    @var2 = field2,
    @var3 = field3

If that's the type of thing you're after

Convert Little Endian to Big Endian

one more suggestion :

unsigned int a = 0xABCDEF23;
a = ((a&(0x0000FFFF)) << 16) | ((a&(0xFFFF0000)) >> 16);
a = ((a&(0x00FF00FF)) << 8) | ((a&(0xFF00FF00)) >>8);

Add string in a certain position in Python

No. Python Strings are immutable.

>>> s='355879ACB6'
>>> s[4:4] = '-'
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: 'str' object does not support item assignment

It is, however, possible to create a new string that has the inserted character:

>>> s[:4] + '-' + s[4:]

Identify if a string is a number

I know this is an old thread, but none of the answers really did it for me - either inefficient, or not encapsulated for easy reuse. I also wanted to ensure it returned false if the string was empty or null. TryParse returns true in this case (an empty string does not cause an error when parsing as a number). So, here's my string extension method:

public static class Extensions
    /// <summary>
    /// Returns true if string is numeric and not empty or null or whitespace.
    /// Determines if string is numeric by parsing as Double
    /// </summary>
    /// <param name="str"></param>
    /// <param name="style">Optional style - defaults to NumberStyles.Number (leading and trailing whitespace, leading and trailing sign, decimal point and thousands separator) </param>
    /// <param name="culture">Optional CultureInfo - defaults to InvariantCulture</param>
    /// <returns></returns>
    public static bool IsNumeric(this string str, NumberStyles style = NumberStyles.Number,
        CultureInfo culture = null)
        double num;
        if (culture == null) culture = CultureInfo.InvariantCulture;
        return Double.TryParse(str, style, culture, out num) && !String.IsNullOrWhiteSpace(str);

Simple to use:

var mystring = "1234.56789";
var test = mystring.IsNumeric();

Or, if you want to test other types of number, you can specify the 'style'. So, to convert a number with an Exponent, you could use:

var mystring = "5.2453232E6";
var test = mystring.IsNumeric(style: NumberStyles.AllowExponent);

Or to test a potential Hex string, you could use:

var mystring = "0xF67AB2";
var test = mystring.IsNumeric(style: NumberStyles.HexNumber)

The optional 'culture' parameter can be used in much the same way.

It is limited by not being able to convert strings that are too big to be contained in a double, but that is a limited requirement and I think if you are working with numbers larger than this, then you'll probably need additional specialised number handling functions anyway.

How to make a hyperlink in telegram without using bots?

In telegram desktop, use this hotkey: ctrl+K

In android:

  1. type your text
  2. select it
  3. and click on Create Link from its options

You can see these steps in this image: link creation in telegram android

Auto populate columns in one sheet from another sheet

In Google Sheets you can use =ArrayFormula(Sheet1!B2:B)on the first cell and it will populate all column contents not sure if that will work in excel

Traits vs. interfaces

The trait is same as a class we can use for multiple inheritance purposes and also code reusability.

We can use trait inside the class and also we can use multiple traits in the same class with 'use keyword'.

The interface is using for code reusability same as a trait

the interface is extend multiple interfaces so we can solve the multiple inheritance problems but when we implement the interface then we should create all the methods inside the class. For more info click below link:

bootstrap 4 responsive utilities visible / hidden xs sm lg not working

Screen Size Class


  1. Hidden on all .d-none

  2. Hidden only on xs .d-none .d-sm-block

  3. Hidden only on sm .d-sm-none .d-md-block

  4. Hidden only on md .d-md-none .d-lg-block

  5. Hidden only on lg .d-lg-none .d-xl-block

  6. Hidden only on xl .d-xl-none

  7. Visible on all .d-block

  8. Visible only on xs .d-block .d-sm-none

  9. Visible only on sm .d-none .d-sm-block .d-md-none

  10. Visible only on md .d-none .d-md-block .d-lg-none

  11. Visible only on lg .d-none .d-lg-block .d-xl-none

  12. Visible only on xl .d-none .d-xl-block

Refer this link

4.5 link:

How to compare arrays in JavaScript?

This I think is the simplest way to do it using JSON stringify, and it may be the best solution in some situations:

JSON.stringify(a1) === JSON.stringify(a2);

This converts the objects a1 and a2 into strings so they can be compared. The order is important in most cases, for that can sort the object using a sort algorithm shown in one of the above answers.

Please do note that you are no longer comparing the object but the string representation of the object. It may not be exactly what you want.

Declare variable MySQL trigger

All DECLAREs need to be at the top. ie.

delimiter //

CREATE TRIGGER pgl_new_user 
    DECLARE m_user_team_id integer;
    DECLARE m_projects_id integer;
    DECLARE cur CURSOR FOR SELECT project_id FROM user_team_project_relationships WHERE user_team_id = m_user_team_id;

    SET @m_user_team_id := (SELECT id FROM user_teams WHERE name = "pgl_reporters");

    OPEN cur;
        ins_loop: LOOP
            FETCH cur INTO m_projects_id;
            IF done THEN
                LEAVE ins_loop;
            END IF;
            INSERT INTO users_projects (user_id, project_id, created_at, updated_at, project_access) 
            VALUES (, m_projects_id, now(), now(), 20);
        END LOOP;
    CLOSE cur;

What is this property in Spring Boot?

This property will register an OpenEntityManagerInViewInterceptor, which registers an EntityManager to the current thread, so you will have the same EntityManager until the web request is finished. It has nothing to do with a Hibernate SessionFactory etc.

Bug? #1146 - Table 'xxx.xxxxx' doesn't exist

I had the same issue. It happened after windows start up error, it seems some files got corrupted due to this. I did import the DB again from the saved script and it works fine.

Sleep Command in T-SQL?

Look at the WAITFOR command.


-- wait for 1 minute

-- wait for 1 second
WAITFOR DELAY '00:00:01'

This command allows you a high degree of precision but is only accurate within 10ms - 16ms on a typical machine as it relies on GetTickCount. So, for example, the call WAITFOR DELAY '00:00:00:001' is likely to result in no wait at all.


You need to replace it as WHERE clockDate = { fn CURRENT_DATE() } AND userName = 'test'. Please remove extra ")" from { fn CURRENT_DATE() })

PHP to write Tab Characters inside a file?

Use \t and enclose the string with double-quotes:

$chunk = "abc\tdef\tghi";

How can I check the syntax of Python script without executing it?

You can check the syntax by compiling it:

python -m py_compile

How do I scroll to an element within an overflowed Div?

The $innerListItem.position().top is actually relative to the .scrollTop() of its first positioned ancestor. So the way to calculate the correct $parentDiv.scrollTop() value is to begin by making sure that $parentDiv is positioned. If it doesn't already have an explicit position, use position: relative. The elements $innerListItem and all its ancestors up to $parentDiv need to have no explicit position. Now you can scroll to the $innerListItem with:

// Scroll to the top
$parentDiv.scrollTop($parentDiv.scrollTop() + $innerListItem.position().top);

// Scroll to the center
$parentDiv.scrollTop($parentDiv.scrollTop() + $innerListItem.position().top
    - $parentDiv.height()/2 + $innerListItem.height()/2);

How to display a jpg file in Python?

Don't forget to include

import Image

In order to show it use this :'pathToFile').show()

What is the simplest way to write the contents of a StringBuilder to a text file in .NET 1.1?

You still have access to StreamWriter:

using (System.IO.StreamWriter file = new System.IO.StreamWriter(@"\hereIam.txt"))
    file.WriteLine(sb.ToString()); // "sb" is the StringBuilder

From the MSDN documentation: Writing to a Text File (Visual C#).

For newer versions of the .NET Framework (Version 2.0. onwards), this can be achieved with one line using the File.WriteAllText method.

System.IO.File.WriteAllText(@"C:\TextFile.txt", stringBuilder.ToString());

ImportError: No module named 'pygame'

Here are instructions for users with the newer Python 3.5 (Google brought me here, I suspect other 3.5 users might end up here as well):

I just successfully installed Pygame 1.9.2a0-cp35 on Windows and it runs with Python 3.5.1.

  • Install Python, and remember the install location
  • Go here and download pygame-1.9.2a0-cp35-none-win32.whl
  • Move the downloaded .whl file to your python35/Scripts directory
  • Open a command prompt in the Scripts directory (Shift-Right click in the directory > Open a command window here)
  • Enter the command:

    pip3 install pygame-1.9.2a0-cp35-none-win32.whl

  • If you get an error in the last step, try:

    python -m pip install pygame-1.9.2a0-cp35-none-win32.whl

And that should do it. Tested as working on Windows 10 64bit.

CSS: Force float to do a whole new line

This is what I did. Seems to work in forcing a new line, but I'm not an html/css guru by any measure.


How do search engines deal with AngularJS applications?

Let's get definitive about AngularJS and SEO

Google, Yahoo, Bing, and other search engines crawl the web in traditional ways using traditional crawlers. They run robots that crawl the HTML on web pages, collecting information along the way. They keep interesting words and look for other links to other pages (these links, the amount of them and the number of them come into play with SEO).

So why don't search engines deal with javascript sites?

The answer has to do with the fact that the search engine robots work through headless browsers and they most often do not have a javascript rendering engine to render the javascript of a page. This works for most pages as most static pages don't care about JavaScript rendering their page, as their content is already available.

What can be done about it?

Luckily, crawlers of the larger sites have started to implement a mechanism that allows us to make our JavaScript sites crawlable, but it requires us to implement a change to our site.

If we change our hashPrefix to be #! instead of simply #, then modern search engines will change the request to use _escaped_fragment_ instead of #!. (With HTML5 mode, i.e. where we have links without the hash prefix, we can implement this same feature by looking at the User Agent header in our backend).

That is to say, instead of a request from a normal browser that looks like:!/signup/page

A search engine will search the page with:

We can set the hash prefix of our Angular apps using a built-in method from ngRoute:

angular.module('myApp', [])
.config(['$location', function($location) {

And, if we're using html5Mode, we will need to implement this using the meta tag:

<meta name="fragment" content="!">

Reminder, we can set the html5Mode() with the $location service:

angular.module('myApp', [])
function($location) {

Handling the search engine

We have a lot of opportunities to determine how we'll deal with actually delivering content to search engines as static HTML. We can host a backend ourselves, we can use a service to host a back-end for us, we can use a proxy to deliver the content, etc. Let's look at a few options:


We can write a service to handle dealing with crawling our own site using a headless browser, like phantomjs or zombiejs, taking a snapshot of the page with rendered data and storing it as HTML. Whenever we see the query string ?_escaped_fragment_ in a search request, we can deliver the static HTML snapshot we took of the page instead of the pre-rendered page through only JS. This requires us to have a backend that delivers our pages with conditional logic in the middle. We can use something like's backend as a starting point to run this ourselves. Of course, we still need to handle the proxying and the snippet handling, but it's a good start.

With a paid service

The easiest and the fastest way to get content into search engine is to use a service Brombone, seo.js, seo4ajax, and are good examples of these that will host the above content rendering for you. This is a good option for the times when we don't want to deal with running a server/proxy. Also, it's usually super quick.

For more information about Angular and SEO, we wrote an extensive tutorial on it at and we detailed it even more in our book ng-book: The Complete Book on AngularJS. Check it out at

How to animate a View with Translate Animation in Android

In order to move a View anywhere on the screen, I would recommend placing it in a full screen layout. By doing so, you won't have to worry about clippings or relative coordinates.

You can try this sample code:


<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android=""
    android:orientation="vertical" android:id="@+id/rootLayout">

        android:text="MOVE" android:layout_centerHorizontal="true"/>

        android:src="@drawable/ic_launcher" android:layout_marginLeft="10dip"/>
        android:src="@drawable/ic_launcher" android:layout_centerVertical="true" android:layout_alignParentRight="true"/>
        android:src="@drawable/ic_launcher" android:layout_marginLeft="60dip" android:layout_alignParentBottom="true" android:layout_marginBottom="100dip"/>

        android:orientation="vertical" android:clipChildren="false" android:clipToPadding="false">

            android:src="@drawable/ic_launcher" android:layout_marginLeft="60dip" android:layout_marginTop="150dip"/>


Your activity

public void onCreate(Bundle savedInstanceState) {

    ((Button) findViewById( )).setOnClickListener( new OnClickListener()
        public void onClick(View v)
            ImageView img = (ImageView) findViewById( );              
            moveViewToScreenCenter( img );
            img = (ImageView) findViewById( );
            moveViewToScreenCenter( img );
            img = (ImageView) findViewById( );                
            moveViewToScreenCenter( img );
            img = (ImageView) findViewById( );
            moveViewToScreenCenter( img );

private void moveViewToScreenCenter( View view )
    RelativeLayout root = (RelativeLayout) findViewById( );
    DisplayMetrics dm = new DisplayMetrics();
    this.getWindowManager().getDefaultDisplay().getMetrics( dm );
    int statusBarOffset = dm.heightPixels - root.getMeasuredHeight();

    int originalPos[] = new int[2];
    view.getLocationOnScreen( originalPos );

    int xDest = dm.widthPixels/2;
    xDest -= (view.getMeasuredWidth()/2);
    int yDest = dm.heightPixels/2 - (view.getMeasuredHeight()/2) - statusBarOffset;

    TranslateAnimation anim = new TranslateAnimation( 0, xDest - originalPos[0] , 0, yDest - originalPos[1] );
    anim.setFillAfter( true );

The method moveViewToScreenCenter gets the View's absolute coordinates and calculates how much distance has to move from its current position to reach the center of the screen. The statusBarOffset variable measures the status bar height.

I hope you can keep going with this example. Remember that after the animation your view's position is still the initial one. If you tap the MOVE button again and again the same movement will repeat. If you want to change your view's position do it after the animation is finished.

Manually type in a value in a "Select" / Drop-down HTML list?

ExtJS has a ComboBox control that can do this (and a whole host of other cool stuff!!)

EDIT: Browse all controls etc, here:

Why is NULL undeclared?

NULL is not a built-in constant in the C or C++ languages. In fact, in C++ it's more or less obsolete, just use a plain literal 0 instead, the compiler will do the right thing depending on the context.

In newer C++ (C++11 and higher), use nullptr (as pointed out in a comment, thanks).

Otherwise, add

#include <stddef.h>

to get the NULL definition.

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 '${:,.2f}'.format(amount)
        return '-${:,.2f}'.format(-amount)

Java getting the Enum name given the Enum Value

In such cases, you can convert the values of enum to a List and stream through it. Something like below examples. I would recommend using filter().

Using ForEach:

List<Category> category = Arrays.asList(Category.values()); -> {
                String name =;

Or, using Filter:

When you want to find with code:

List<Category> categoryList = Arrays.asList(Category.values());
Category category = -> eachCategory.toString().equals("3")).findAny().orElse(null);

System.out.println(category.toString() + " " +;

When you want to find with name:

List<Category> categoryList = Arrays.asList(Category.values());
Category category = ->"Apple")).findAny().orElse(null);

System.out.println(category.toString() + " " +;

Hope it helps! I know this is a very old post, but someone can get help.

Sass calculate percent minus px

Just add the percentage value into a variable and use #{$variable} for example

.selector {
    height: calc(#{$twentyFivePercent} - 5px);

Where is the user's Subversion config file stored on the major operating systems?

In TortoiseSVN you can access and modify some settings in the context menu "Settings/General" in explorer.

E.g. the "Global ignore pattern" can be edited directly in the dialog box. Such changings are the stored in the registry as bahrep pointed out in her answer.

(Win10/TortoiseSVN 1.13.1, Build 28686 - 64 Bit)

Best way to parse command-line parameters?

As everyone posted it's own solution here is mine, cause I wanted something easier to write for the user :

The gist contains a code file, plus a test file and a short example copied here:

import ***.ArgsOps._

object Example {
    val parser = ArgsOpsParser("--someInt|-i" -> 4, "--someFlag|-f", "--someWord" -> "hello")

    def main(args: Array[String]){
        val argsOps = parser <<| args
        val someInt : Int = argsOps("--someInt")
        val someFlag : Boolean = argsOps("--someFlag")
        val someWord : String = argsOps("--someWord")
        val otherArgs = argsOps.args

        foo(someWord, someInt, someFlag)

There is not fancy options to force a variable to be in some bounds, cause I don't feel that the parser is the best place to do so.

Note : you can have as much alias as you want for a given variable.

Storing and displaying unicode string (??????) using PHP and MySQL

For those who are looking for PHP ( >5.3.5 ) PDO statement, we can set charset as per below:

$dbh = new PDO('mysql:host=localhost;dbname=testdb;charset=utf8', 'username', 'password');

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

So here is the solution for this:

I check port 80 used by Skype, after that I changes port to 81 and also along with that somewhere i read this error may be because of SSL Port then I changed SSL port to 444. However this got resolved easily.

One most important thing to notice here, all the port changes should be done inside config files, for http port change: httpd.conf for SSL httpd-ssl.conf. Otherwise changes will not replicate to Apache, Sometime PC reboot is also required.

Edit: Make Apache use port 80 and make Skype communicate on other Port

For those who are struggling with Skype, want to change its port and to make Apache to use port 80.

No need to Re-Install, Here is simply how to change Skype Port

Goto: Tools > Options > Advanced > Connection

There you need to uncheck Use port 80 and 443 as alternative for incoming connections.

That's it, here is screen shot of it.

Changing Skype Port

Using SSIS BIDS with Visual Studio 2012 / 2013

Welcome to Microsoft Marketing Speak hell. With the 2012 release of SQL Server, the BIDS, Business Intelligence Designer Studio, plugin for Visual Studio was renamed to SSDT, SQL Server Data Tools. SSDT is available for 2010 and 2012. The problem is, there are two different products called SSDT.

There is SSDT which replaces the database designer thing which was called Data Dude in VS 2008 and in 2010 became database projects. That a free install and if you snag the web installer, that's what you get when you install SSDT. It puts the correct project templates and such into Visual Studio.

There's also the SSDT which is the "BIDS" replacement for developing SSIS, SSRS and SSAS stuff. As of March 2013, it is now available for the 2012 release of Visual Studio. The download is labeled SSDTBI_VS2012_X86.msi Perhaps that's a signal on how the product is going to be referred to in marketing materials. Download links are

None the less, we have Business Intelligence projects available to us in Visual Studio 2012. And the people did rejoice and did feast upon the lambs and toads and tree-sloths and fruit-bats and orangutans and breakfast cereals

enter image description here

The ScriptManager must appear before any controls that need it

The script manager must be put onto the page before it is used. This would be directly on the page itself, or alternatively, if you are using them, on the Master Page.

The markup would be;

 <asp:ScriptManager ID="ScriptManager1" runat="server" LoadScriptsBeforeUI="true"
            EnablePartialRendering="true" />

How to change the commit author for one specific commit?

There is also a lazy approach to this problem, especially if you have more than one commit that you want to change. In my case, I had a new branch with several commits with a wrong author, so what helped me:

Go to your original branch:

git checkout develop

Create new branch from it:

git checkout -b myFeature develop 

Merge it without commit info as one commit:

git merge --no-commit --squash branchWrongAuthor

You might also want to stage changes:

git stage .

Change the name of the author and commit changes:

git commit --amend --author "New Author Name <New Author Email>" -m "new feature added"

And that's it, you can push the changes.

git push

You can delete the branch with a wrong author after that.

What's the difference between SHA and AES encryption?

SHA isn't encryption, it's a one-way hash function. AES (Advanced_Encryption_Standard) is a symmetric encryption standard.

AES Reference

Heap vs Binary Search Tree (BST)

When to use a heap and when to use a BST

Heap is better at findMin/findMax (O(1)), while BST is good at all finds (O(logN)). Insert is O(logN) for both structures. If you only care about findMin/findMax (e.g. priority-related), go with heap. If you want everything sorted, go with BST.

First few slides from here explain things very clearly.

CSS3 Transform Skew One Side

I know this is old, but I would like to suggest using a linear-gradient to achieve the same effect instead of margin offset. This is will maintain any content at its original place.


    <li><a href="#">One</a></li>
    <li><a href="#">Two</a></li>
    <li><a href="#">Three</a></li>


/* reset */
ul, li, a {
    margin: 0; padding: 0;
/* nav stuff */
ul, li, a {
    display: inline-block;
    text-align: center;
/* appearance styling */
ul {
    /* hacks to make one side slant only */
    overflow: hidden;
    background: linear-gradient(to right, red, white, white, red);
li {
    background-color: red;
li a {
    padding: 3px 6px 3px 6px;
    color: #ffffff;
    text-decoration: none;
    width: 80px;

How to solve static declaration follows non-static declaration in GCC C code?

From what the error message complains about, it sounds like you should rather try to fix the source code. The compiler complains about difference in declaration, similar to for instance

void foo(int i);
void foo(double d) {

and this is not valid C code, hence the compiler complains.

Maybe your problem is that there is no prototype available when the function is used the first time and the compiler implicitly creates one that will not be static. If so the solution is to add a prototype somewhere before it is first used.

Basic HTML - how to set relative path to current folder?

You can use


to mean up one level. If you have a page called page2.html in the same folder as page.html then the relative path is:


If you have page2.html at the same level with folder then the path is:


Converting JSON to XLS/CSV in Java

you can use commons csv to convert into CSV format. or use POI to convert into xls. if you need helper to convert into xls, you can use jxls, it can convert java bean (or list) into excel with expression language.

Basically, the json doc maybe is a json array, right? so it will be same. the result will be list, and you just write the property that you want to display in excel format that will be read by jxls. See

If the problem is the json can't be read in the jxls excel property, just serialize it into collection of java bean first.

No process is on the other end of the pipe (SQL Server 2012)

For me the password expired for my login user, and i got the same exception. Then i login with Windows Authentication mode and change the password for the associated user, and it solved my problem.

Flutter command not found

Just revert to chsh -s /bin/bash from chsh -s /bin/zsh,

Run one command

chsh -s /bin/bash

Your facing this problem just because of you have change shell from /bash to /zsh in macOs. If you run this command again it will change the path again. So just run one command and problem solve.

Find a pair of elements from an array whose sum equals a given number

in C#:

        int[] array = new int[] { 1, 5, 7, 2, 9, 8, 4, 3, 6 }; // given array
        int sum = 10; // given sum
        for (int i = 0; i <= array.Count() - 1; i++)
            if (array.Contains(sum - array[i]))
                Console.WriteLine("{0}, {1}", array[i], sum - array[i]);

Git is not working after macOS Update (xcrun: error: invalid active developer path (/Library/Developer/CommandLineTools)

For me what worked is the following:

sudo xcode-select --reset

Then like in @High6's answer:

sudo xcodebuild -license

This will reveal a license which I assume is some Xcode license. Scroll to the bottom using space (or the mouse) then tap agree.

This is what worked for me on MacOS Mojave v 10.14.

Install apk without downloading

For this your android application must have uploaded into the android market. when you upload it on the android market then use the following code to open the market with your android application.

    Intent intent = new Intent(Intent.ACTION_VIEW,Uri.parse("market://details?id=<packagename>"));

If you want it to download and install from your own server then use the following code

Intent intent = new Intent(Intent.ACTION_VIEW,Uri.parse(""));
    startActivity(intent); vs PHP (What to choose)

This is impossible to answer and has been brought up many many times before. Do a search, read those threads, then pick the framework you and your team have experience with.

What is SYSNAME data type in SQL Server?

Another use case is when using the SQL Server 2016+ functionality of AT TIME ZONE

The below statement will return a date converted to GMT


If you want to pass the time zone as a variable, say:


then that variable needs to be of the type sysname (declaring it as varchar will cause an error).

Convert list to tuple in Python

I find many answers up to date and properly answered but will add something new to stack of answers.

In python there are infinite ways to do this, here are some instances
Normal way

>>> l= [1,2,"stackoverflow","python"]
>>> l
[1, 2, 'stackoverflow', 'python']
>>> tup = tuple(l)
>>> type(tup)
<type 'tuple'>
>>> tup
(1, 2, 'stackoverflow', 'python')

smart way

>>>tuple(item for item in l)
(1, 2, 'stackoverflow', 'python')

Remember tuple is immutable ,used for storing something valuable. For example password,key or hashes are stored in tuples or dictionaries. If knife is needed why to use sword to cut apples. Use it wisely, it will also make your program efficient.

Sublime Text 2 multiple line edit

Windows: I prefer Alt+F3 to search a string and change all instances of search string at once.

How do I create an Excel (.XLS and .XLSX) file in C# without installing Microsoft Office?

You may want to take a look at GemBox.Spreadsheet.

They have a free version with all features but limited to 150 rows per sheet and 5 sheets per workbook, if that falls within your needs.

I haven't had need to use it myself yet, but does look interesting.

Swift 3: Display Image from URL

Use extension for UIImageView to Load URL Images.

let imageCache = NSCache<NSString, UIImage>()

extension UIImageView {

    func imageURLLoad(url: URL) { { [weak self] in
            func setImage(image:UIImage?) {
                DispatchQueue.main.async {
                    self?.image = image
            let urlToString = url.absoluteString as NSString
            if let cachedImage = imageCache.object(forKey: urlToString) {
                setImage(image: cachedImage)
            } else if let data = try? Data(contentsOf: url), let image = UIImage(data: data) {
                DispatchQueue.main.async {
                    imageCache.setObject(image, forKey: urlToString)
                    setImage(image: image)
            }else {
                setImage(image: nil)

How can I upgrade NumPy?

Because you have multiple versions of NumPy installed.

Try pip uninstall numpy and pip list | grep numpy several times, until you see no output from pip list | grep numpy.

Then pip install numpy will get you the newest version of NumPy.

How to select a schema in postgres when using psql?

In PostgreSQL the system determines which table is meant by following a search path, which is a list of schemas to look in.

The first matching table in the search path is taken to be the one wanted, otherwise, if there is no match a error is raised, even if matching table names exist in other schemas in the database.

To show the current search path you can use the following command:

SHOW search_path;

And to put the new schema in the path, you could use:

SET search_path TO myschema;

Or if you want multiple schemas:

SET search_path TO myschema, public;


Showing which files have changed between two revisions

There are two branches lets say

  • A (Branch on which you are working)
  • B (Another branch with which you want to compare)

Being in branch A you can type

git diff --color B

then this will give you a output of

enter image description here

The important point about this is

  1. Text in green is inside present in Branch A

  2. Text in red is present in Branch B

How to escape the % (percent) sign in C's printf?

If there are no formats in the string, you can use puts (or fputs):


if there is a format in the string:

printf("%.2f%%", 53.2);

As noted in the comments, puts appends a \n to the output and fputs does not.

How to print to console when using Qt

It also has a syntax similar to prinft, e.g.:

qDebug ("message %d, says: %s",num,str); 

Very handy as well

Hibernate Error: org.hibernate.NonUniqueObjectException: a different object with the same identifier value was already associated with the session

One workaround to solve this issue is try to read the object back from hibernate cache/db before you make any updates and then persist.


            OrderHeader oh = orderHeaderDAO.get(orderHeaderId);

Note: Keep in mind that this does not fix the root cause but solves the issue.

Java Serializable Object to Byte Array

In case you want a nice no dependencies copy-paste solution. Grab the code below.


MyObject myObject = ...

byte[] bytes = SerializeUtils.serialize(myObject);
myObject = SerializeUtils.deserialize(bytes);



public class SerializeUtils {

    public static byte[] serialize(Serializable value) throws IOException {
        ByteArrayOutputStream out = new ByteArrayOutputStream();

        try(ObjectOutputStream outputStream = new ObjectOutputStream(out)) {

        return out.toByteArray();

    public static <T extends Serializable> T deserialize(byte[] data) throws IOException, ClassNotFoundException {
        try(ByteArrayInputStream bis = new ByteArrayInputStream(data)) {
            //noinspection unchecked
            return (T) new ObjectInputStream(bis).readObject();

Get Substring - everything before certain char

String str = "223232-1.jpg"
int index = str.IndexOf('-');
if(index > 0) {
    return str.Substring(0, index)

What languages are Windows, Mac OS X and Linux written in?

The Linux kernel is mostly written in C (and a bit of assembly language, I'd imagine), but some of the important userspace utilities (programs) are shell scripts written in the Bash scripting language. Beyond that, it's sort of hard to define "Linux" since you basically build a Linux system by picking bits and pieces you want and putting them together, and depending on what an individual Linux user wants, you can get pretty much any language involved. (As Paul said, Python and C++ play important roles)

How to install plugin for Eclipse from .zip

Download the plugin, extract it inside eclipse/dropins folder and restart your Eclipse IDE. You may require to pass --clean along with eclipse command

how to stop a loop arduino

just use this line to exit function:


How can I trim leading and trailing white space?

Probably the best way is to handle the trailing white spaces when you read your data file. If you use read.csv or read.table you can set the parameterstrip.white=TRUE.

If you want to clean strings afterwards you could use one of these functions:

# Returns string without leading white space
trim.leading <- function (x)  sub("^\\s+", "", x)

# Returns string without trailing white space
trim.trailing <- function (x) sub("\\s+$", "", x)

# Returns string without leading or trailing white space
trim <- function (x) gsub("^\\s+|\\s+$", "", x)

To use one of these functions on myDummy$country:

 myDummy$country <- trim(myDummy$country)

To 'show' the white space you could use:


which will show you the strings surrounded by quotation marks (") making white spaces easier to spot.

Python Regex - How to Get Positions and Values of Matches

Taken from

Regular Expression HOWTO

span() returns both start and end indexes in a single tuple. Since the match method only checks if the RE matches at the start of a string, start() will always be zero. However, the search method of RegexObject instances scans through the string, so the match may not start at zero in that case.

>>> p = re.compile('[a-z]+')
>>> print p.match('::: message')
>>> m ='::: message') ; print m
<re.MatchObject instance at 80c9650>
>>> m.span()
(4, 11)

Combine that with:

In Python 2.2, the finditer() method is also available, returning a sequence of MatchObject instances as an iterator.

>>> p = re.compile( ... )
>>> iterator = p.finditer('12 drummers drumming, 11 ... 10 ...')
>>> iterator
<callable-iterator object at 0x401833ac>
>>> for match in iterator:
...     print match.span()
(0, 2)
(22, 24)
(29, 31)

you should be able to do something on the order of

for match in re.finditer(r'[a-z]', 'a1b2c3d4'):
   print match.span()

What character represents a new line in a text area

Talking specifically about textareas in web forms, for all textareas, on all platforms, \r\n will work.

If you use anything else you will cause issues with cut and paste on Windows platforms.

The line breaks will be canonicalised by windows browsers when the form is submitted, but if you send the form down to the browser with \n linebreaks, you will find that the text will not copy and paste correctly between for example notepad and the textarea.

Interestingly, in spite of the Unix line end convention being \n, the standard in most text-based network protocols including HTTP, SMTP, POP3, IMAP, and so on is still \r\n. Yes, it may not make a lot of sense, but that's history and evolving standards for you!

What is the meaning of 'No bundle URL present' in react-native?

For me the issue was it couldn't create the JS bundle. It doesn't state the error when building from Xcode so there is no way for you to know this. To find the error run the following command.

react-native bundle --platform ios --dev false --entry-file index.ios.js --bundle-output ./ios/release/main.jsbundle --assets-dest ./ios/release/main.jsbundle

For me the error was something with missing PureRenderMixin component. To which the solution can be found here: Basicly you have to manually install [email protected]. This can be done via running this command.

npm i --save [email protected]

This issue is now happening for everybody because newer versions of react alphas are being released (particularly alpha.5) and they are breaking react-native builds.

Difference between `npm start` & `node app.js`, when starting app?

The documentation has been updated. My answer has substantial changes vs the accepted answer: I wanted to reflect documentation is up-to-date, and accepted answer has a few broken links.

Also, I didn't understand when the accepted answer said "it defaults to node server.js". I think the documentation clarifies the default behavior:


Start a package


npm start [-- <args>]


This runs an arbitrary command specified in the package's "start" property of its "scripts" object. If no "start" property is specified on the "scripts" object, it will run node server.js.

In summary, running npm start could do one of two things:

  1. npm start {command_name}: Run an arbitrary command (i.e. if such command is specified in the start property of package.json's scripts object)
  2. npm start: Else if no start property exists (or no command_name is passed): Run node server.js, (which may not be appropriate, for example the OP doesn't have server.js; the OP runs nodeapp.js )
  3. I said I would list only 2 items, but are other possibilities (i.e. error cases). For example, if there is no package.json in the directory where you run npm start, you may see an error: npm ERR! enoent ENOENT: no such file or directory, open '.\package.json'

Error In PHP5 ..Unable to load dynamic library

sudo apt-get install php5-mcrypt
sudo apt-get install php5-mysql

...etc resolved it for me :)

hope it helps

Find object by its property in array of objects with AngularJS way

The solucion that work for me is the following

$filter('filter')(data, {'id':10}) 

How to use DISTINCT and ORDER BY in same SELECT statement?

By subquery, it should work:

    SELECT distinct(Category) from MonitoringJob  where Category in(select Category from MonitoringJob order by CreationDate desc);

change <audio> src with javascript

with jQuery:

 $("#playerSource").attr("src", "new_src");

    var audio = $("#player");      

    audio[0].load();//suspends and restores all audio element

    if (isAutoplay) 

Change a HTML5 input's placeholder color with CSS

How about this

<input type="text" value="placeholder text" onfocus="'#000'; _x000D_
    this.value='';" style="color: #f00;" />

No CSS or placeholder, but you get the same functionality.

foreach loop in angularjs

you have to use nested angular.forEach loops for JSON as shown below:

 var values = [

        angular.forEach(value,function(v1,k1){//this is nested angular.forEach loop

How to stop a looping thread in Python?

My solution is:

import threading, time

def a():
    t = threading.currentThread()
    while getattr(t, "do_run", True):
    print('Do something')

def getThreadByName(name):
    threads = threading.enumerate() #Threads list
    for thread in threads:
        if == name:
            return thread

threading.Thread(target=a, name='228').start() #Init thread
t = getThreadByName('228') #Get thread by name
t.do_run = False #Signal to stop thread

Routing HTTP Error 404.0 0x80070002

The problem for me was a new server that System.Web.Routing was of version 3.5 while web.config requested version The resolution was

%WINDIR%\Framework\v4.0.30319\aspnet_regiis -i

%WINDIR%\Framework64\v4.0.30319\aspnet_regiis -i

Windows path in Python

you can use always:


this works both in linux and windows. Other posibility is


if you have problems with some names you can also try raw string literals:


however best practice is to use the os.path module functions that always select the correct configuration for your OS:

os.path.join(mydir, myfile)

From python 3.4 you can also use the pathlib module. This is equivelent to the above:

pathlib.Path(mydir, myfile)


pathlib.Path(mydir) / myfile

PHP - concatenate or directly insert variables in string

Between those two syntaxes, you should really choose the one you prefer :-)

Personally, I would go with your second solution in such a case (Variable interpolation), which I find easier to both write and read.

The result will be the same; and even if there are performance implications, those won't matter 1.

As a sidenote, so my answer is a bit more complete: the day you'll want to do something like this:

echo "Welcome $names!";

PHP will interpret your code as if you were trying to use the $names variable -- which doesn't exist. - note that it will only work if you use "" not '' for your string.

That day, you'll need to use {}:

echo "Welcome {$name}s!"

No need to fallback to concatenations.

Also note that your first syntax:

echo "Welcome ".$name."!";

Could probably be optimized, avoiding concatenations, using:

echo "Welcome ", $name, "!";

(But, as I said earlier, this doesn't matter much...)

1 - Unless you are doing hundreds of thousands of concatenations vs interpolations -- and it's probably not quite the case.

Java: using switch statement with enum under subclass

Change it to this:

switch (enumExample) {
    case VALUE_A: {

The clue is in the error. You don't need to qualify case labels with the enum type, just its value.

In AngularJS, what's the difference between ng-pristine and ng-dirty?

As already stated in earlier answers, ng-pristine is for indicating that the field has not been modified, whereas ng-dirty is for telling it has been modified. Why need both?

Let's say we've got a form with phone and e-mail address among the fields. Either phone or e-mail is required, and you also have to notify the user when they've got invalid data in each field. This can be accomplished by using ng-dirty and ng-pristine together:

<form name="myForm">
    <input name="email" ng-model="" ng-required="!">
    <div class="error" 
         ng-show="$invalid && 
        $pristine &&
        $pristine">Phone or e-mail required</div>
    <div class="error" 
         ng-show="$invalid &&$dirty">
        E-mail is invalid

    <input name="phone" ng-model="" ng-required="!">
    <div class="error" 
         ng-show="$invalid && 
        $pristine &&
        $pristine">Phone or e-mail required</div>
    <div class="error" 
         ng-show="$invalid &&$dirty">
        Phone is invalid

How to display HTML <FORM> as inline element?

You can accomplish what you want, I think, simply by including the submit button within the paragraph:

     <p>Read this sentence  <input  type='submit' value='or push this button'/></p>

Cannot connect to MySQL Workbench on mac. Can't connect to MySQL server on '' (61) Mac Macintosh

I ran into the same scenario

I opened "System Preferences", clicked "MySQL", then clicked "Initialize Database" button. I entered a new password and saved it in a safe place. After that i restarted the MySql Instance (in the System Preferences dialog as well). After that i opened MySqlWorkbench and opened the default connection, entered the password i set before and: Viola, i can do whatever i want :-)

Get file path of image on Android

I am doing this on click of Button.

private static final int CAMERA_PIC_REQUEST = 1;

private View.OnClickListener  OpenCamera=new View.OnClickListener() {

            public void onClick(View paramView) {
                // TODO Auto-generated method stub

                Intent cameraIntent = new Intent(android.provider.MediaStore.ACTION_IMAGE_CAPTURE);

                //outfile where we are thinking of saving it
                Date date = new Date();
                SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd HH-mm-ss");

                String newPicFile = RecipeName+ df.format(date) + ".png";

                String outPath =Environment.getExternalStorageDirectory() + "/myFolderName/"+ newPicFile ;
                File outFile = new File(outPath);               

                Uri outuri = Uri.fromFile(outFile);
                cameraIntent.putExtra(android.provider.MediaStore.EXTRA_OUTPUT, outuri);            
                startActivityForResult(cameraIntent, CAMERA_PIC_REQUEST);  


You can get the URL of the recently Captured Image from variable CapturedImageURL

protected void onActivityResult(int requestCode, int resultCode, Intent data) {  

    if (requestCode == CAMERA_PIC_REQUEST) {  
        // do something  

         if (resultCode == RESULT_OK) 
             Uri uri = null;

             if (data != null) 
                 uri = data.getData();
             if (uri == null && CapturedImageURL != null) 
                 uri = Uri.fromFile(new File(CapturedImageURL));
             File file = new File(CapturedImageURL);
             if (!file.exists()) {
                sendBroadcast(new Intent(Intent.ACTION_MEDIA_MOUNTED, Uri.parse("file://"+Environment.getExternalStorageDirectory())));



Circle drawing with SVG's arc path

These answers are much too complicated.

A simpler way to do this without creating two arcs or convert to different coordinate systems..

This assumes your canvas area has width w and height h.

`M${w*0.5 + radius},${h*0.5}
 A${radius} ${radius} 0 1 0 ${w*0.5 + radius} ${h*0.5001}`

Just use the "long arc" flag, so the full flag is filled. Then make the arcs 99.9999% the full circle. Visually it is the same. Avoid the sweep flag by just starting the circle at the rightmost point in the circle (one radius directly horizontal from the center).

Counter inside xsl:for-each loop

Try inserting <xsl:number format="1. "/><xsl:value-of select="."/><xsl:text> in the place of ???.

Note the "1. " - this is the number format. More info: here

How to Join to first row

Tried the cross, works nicely, but takes slightly longer. Adjusted line columns to have max and added group which kept speed and dropped the extra record.

Here's the adjusted query:

SELECT Orders.OrderNumber, max(LineItems.Quantity), max(LineItems.Description)
FROM Orders
    INNER JOIN LineItems 
    ON Orders.OrderID = LineItems.OrderID
Group by Orders.OrderNumber

Getting multiple selected checkbox values in a string in javascript and PHP

This is a variation to get all checked checkboxes in all_location_id without using an "if" statement

var all_location_id = document.querySelectorAll('input[name="location[]"]:checked');

var aIds = [];

for(var x = 0, l = all_location_id.length; x < l;  x++)

var str = aIds.join(', ');


Convert spark DataFrame column to python list

On my data I got these benchmarks:

>>> x: x).collect()

0.52 sec

>>> [row[col] for row in data.collect()]

0.271 sec

>>> list([col])

0.427 sec

The result is the same

Convert Unicode to ASCII without errors in Python

Looks like you are using python 2.x. Python 2.x defaults to ascii and it doesn’t know about Unicode. Hence the exception.

Just paste the below line after shebang, it will work

# -*- coding: utf-8 -*-

Query to get only numbers from a string


    string NVARCHAR(50)

INSERT INTO @temp (string)
    ('003Preliminary Examination Plan'),

SELECT SUBSTRING(string, PATINDEX('%[0-9]%', string), PATINDEX('%[0-9][^0-9]%', string + 't') - PATINDEX('%[0-9]%', 
                    string) + 1) AS Number
FROM @temp

Efficiently counting the number of lines of a text file. (200mb+)

If you're under linux you can simply do:

number_of_lines = intval(trim(shell_exec("wc -l ".$file_name." | awk '{print $1}'")));

You just have to find the right command if you're using another OS


ValueError: not enough values to unpack (expected 11, got 1)

The error message is fairly self-explanatory

(a,b,c,d,e) = line.split()

expects line.split() to yield 5 elements, but in your case, it is only yielding 1 element. This could be because the data is not in the format you expect, a rogue malformed line, or maybe an empty line - there's no way to know.

To see what line is causing the issue, you could add some debug statements like this:

if len(line.split()) != 11:
    print line

As Martin suggests, you might also be splitting on the wrong delimiter.

How to restore SQL Server 2014 backup in SQL Server 2008

No, it is not possible. Stack Overflow wants me to answer with a longer answer, so I will say no again.


Backups that are created by more recent version of SQL Server cannot be restored in earlier versions of SQL Server.

PHP - auto refreshing page

<meta http-equiv="refresh" content="10" >

This can work. Try it..!! :-)

How to use vim in the terminal?

You can definetely build your code from Vim, that's what the :make command does.

However, you need to go through the basics first : type vimtutor in your terminal and follow the instructions to the end.

After you have completed it a few times, open an existing (non-important) text file and try out all the things you learned from vimtutor: entering/leaving insert mode, undoing changes, quitting/saving, yanking/putting, moving and so on.

For a while you won't be productive at all with Vim and will probably be tempted to go back to your previous IDE/editor. Do that, but keep up with Vim a little bit every day. You'll probably be stopped by very weird and unexpected things but it will happen less and less.

In a few months you'll find yourself hitting o, v and i all the time in every textfield everywhere.

Have fun!

Can I call a constructor from another constructor (do constructor chaining) in C++?

If you want to be evil, you can use the in-place "new" operator:

class Foo() {
    Foo() { /* default constructor deliciousness */ }
    Foo(Bar myParam) {
      new (this) Foo();
      /* bar your param all night long */

Seems to work for me.


As @ElvedinHamzagic points out, if Foo contained an object which allocated memory, that object might not be freed. This complicates things further.

A more general example:

class Foo() {
  std::vector<int> Stuff;
      : Stuff(42)
      /* default constructor deliciousness */

    Foo(Bar myParam)
      new (this) Foo();
      /* bar your param all night long */

Looks a bit less elegant, for sure. @JohnIdol's solution is much better.

What's the difference between jquery.js and jquery.min.js?

  • jquery.js = Pretty and easy to read :) Read this one.

  • jquery.min.js = Looks like jibberish! But has a smaller file size. Put this one on your site.

Both are the same in functionality. The difference is only in whether it's formatted nicely for readability or compactly for smaller file size.

Specifically, the second one is minified, a process which involves removing unnecessary whitespace and shortening variable names. Both contribute to making the code much harder to read: the removal of whitespace removes line breaks and spaces messing up the formatting, and the shortening of variable names (including some function names) replaces the original variable names with meaningless letters.

All this is done in such a way that it doesn't affect the way the code behaves when run, in any way. Notably, the replacement/shortening of variable and function names is only done to names that appear in a local scope where it won't interfere with any other code in other scripts.

installing cPickle with python 3.5

cPickle comes with the standard library… in python 2.x. You are on python 3.x, so if you want cPickle, you can do this:

>>> import _pickle as cPickle

However, in 3.x, it's easier just to use pickle.

No need to install anything. If something requires cPickle in python 3.x, then that's probably a bug.

Using tr to replace newline with space

Best guess is you are on windows and your line ending settings are set for windows. See this topic: How to change line-ending settings

or use:

tr '\r\n' ' '

Dictionary of dictionaries in Python?

Using collections.defaultdict is a big time-saver when you're building dicts and don't know beforehand which keys you're going to have.

Here it's used twice: for the resulting dict, and for each of the values in the dict.

import collections

def aggregate_names(errors):
    result = collections.defaultdict(lambda: collections.defaultdict(list))
    for real_name, false_name, location in errors:
    return result

Combining this with your code:

dictionary = aggregate_names(previousFunction(string))

Or to test:

    ('Fred', 'Frad', 123),
    ('Jim', 'Jam', 100),
    ('Fred', 'Frod', 200),
    ('Fred', 'Frad', 300)]
print aggregate_names(EXAMPLES)

Dynamically create checkbox with JQuery from text input

One of the elements to consider as you design your interface is on what event (when A takes place, B happens...) does the new checkbox end up being added?

Let's say there is a button next to the text box. When the button is clicked the value of the textbox is turned into a new checkbox. Our markup could resemble the following...

<div id="checkboxes">
    <input type="checkbox" /> Some label<br />
    <input type="checkbox" /> Some other label<br />

<input type="text" id="newCheckText" /> <button id="addCheckbox">Add Checkbox</button>

Based on this markup your jquery could bind to the click event of the button and manipulate the DOM.

$('#addCheckbox').click(function() {
    var text = $('#newCheckText').val();
    $('#checkboxes').append('<input type="checkbox" /> ' + text + '<br />');