Programs & Examples On #Coldfusion 7

For issues relating to using ColdFusion, version 7.

Get first row of dataframe in Python Pandas based on criteria

For the point that 'returns the value as soon as you find the first row/record that meets the requirements and NOT iterating other rows', the following code would work:

def pd_iter_func(df):
    for row in df.itertuples():
        # Define your criteria here
        if row.A > 4 and row.B > 3:
            return row

It is more efficient than Boolean Indexing when it comes to a large dataframe.

To make the function above more applicable, one can implements lambda functions:

def pd_iter_func(df: DataFrame, criteria: Callable[[NamedTuple], bool]) -> Optional[NamedTuple]:
    for row in df.itertuples():
        if criteria(row):
            return row

pd_iter_func(df, lambda row: row.A > 4 and row.B > 3)

As mentioned in the answer to the 'mirror' question, pandas.Series.idxmax would also be a nice choice.

def pd_idxmax_func(df, mask):
    return df.loc[mask.idxmax()]

pd_idxmax_func(df, (df.A > 4) & (df.B > 3))

Which Eclipse version should I use for an Android app?

Just because it's not on here Nvidia has a nice package that simplifies getting it set up and running with an added bonus of supporting 3D acceleration on capable TEGRA enabled devices.

You may find it here.

Passing array in GET for a REST call

As @Ravi_MCA mentioned, /users?ids[]=id1&ids[]=id2 worked for me, too.

When you want to send an array through PATCH or POST method, it's better to use JSON or XML. (I use JSON)
In HTTP Request body you should follow like this:

{"params":["arg1", "arg2", ...]}

You can even use JSON object instead of array.

Export SQL query data to Excel

I don't know if this is what you're looking for, but you can export the results to Excel like this:

In the results pane, click the top-left cell to highlight all the records, and then right-click the top-left cell and click "Save Results As". One of the export options is CSV.

You might give this a shot too:

   'Excel 8.0;Database=c:\Test.xls;','SELECT productid, price FROM dbo.product')

Lastly, you can look into using SSIS (replaced DTS) for data exports. Here is a link to a tutorial:

== Update #1 ==

To save the result as CSV file with column headers, one can follow the steps shown below:

  1. Go to Tools->Options
  2. Query Results->SQL Server->Results to Grid
  3. Check “Include column headers when copying or saving results”
  4. Click OK.
  5. Note that the new settings won’t affect any existing Query tabs — you’ll need to open new ones and/or restart SSMS.

Adding 'serial' to existing column in Postgres

Look at the following commands (especially the commented block).


CREATE TABLE foo (a int, b text);
CREATE TABLE bar (a serial, b text);

INSERT INTO foo (a, b) SELECT i, 'foo ' || i::text FROM generate_series(1, 5) i;
INSERT INTO bar (b) SELECT 'bar ' || i::text FROM generate_series(1, 5) i;

-- blocks of commands to turn foo into bar
ALTER TABLE foo ALTER COLUMN a SET DEFAULT nextval('foo_a_seq');
ALTER SEQUENCE foo_a_seq OWNED BY foo.a;    -- 8.2 or later

SELECT setval('foo_a_seq', 5);  -- replace 5 by SELECT MAX result

INSERT INTO foo (b) VALUES('teste');
INSERT INTO bar (b) VALUES('teste');


How to get a list of properties with a given attribute?

var props = t.GetProperties().Where(
                prop => Attribute.IsDefined(prop, typeof(MyAttribute)));

This avoids having to materialize any attribute instances (i.e. it is cheaper than GetCustomAttribute[s]().

Get year, month or day from numpy datetime64

This is how I do it.

import numpy as np

def dt2cal(dt):
    Convert array of datetime64 to a calendar array of year, month, day, hour,
    minute, seconds, microsecond with these quantites indexed on the last axis.

    dt : datetime64 array (...)
        numpy.ndarray of datetimes of arbitrary shape

    cal : uint32 array (..., 7)
        calendar array with last axis representing year, month, day, hour,
        minute, second, microsecond

    # allocate output 
    out = np.empty(dt.shape + (7,), dtype="u4")
    # decompose calendar floors
    Y, M, D, h, m, s = [dt.astype(f"M8[{x}]") for x in "YMDhms"]
    out[..., 0] = Y + 1970 # Gregorian Year
    out[..., 1] = (M - Y) + 1 # month
    out[..., 2] = (D - M) + 1 # dat
    out[..., 3] = (dt - D).astype("m8[h]") # hour
    out[..., 4] = (dt - h).astype("m8[m]") # minute
    out[..., 5] = (dt - m).astype("m8[s]") # second
    out[..., 6] = (dt - s).astype("m8[us]") # microsecond
    return out

It's vectorized across arbitrary input dimensions, it's fast, its intuitive, it works on numpy v1.15.4, it doesn't use pandas.

I really wish numpy supported this functionality, it's required all the time in application development. I always get super nervous when I have to roll my own stuff like this, I always feel like I'm missing an edge case.

How to create an alert message in jsp page after submit process is complete

in your servlet

 return mapping.findForward("success");

In your jsp

<c:if test="${not empty submitDone}">
  <script>alert("Form submitted");

JavaScript, get date of the next day

Using Date object guarantees that. For eg if you try to create April 31st :

new Date(2014,3,31)        // Thu May 01 2014 00:00:00

Please note that it's zero indexed, so Jan. is 0, Feb. is 1 etc.

Check if int is between two numbers

You could make your own

public static boolean isBetween(int a, int b, int c) {
    return b > a ? c > a && c < b : c > b && c < a;

Edit: sorry checks if c is between a and b

How to make the overflow CSS property work with hidden as value

Ok if anyone else is having this problem this may be your answer:

If you are trying to hide absolute positioned elements make sure the container of those absolute positioned elements is relatively positioned.

Can not find module “@angular-devkit/build-angular”

Run the below command to get it resolved. Whenever you pull a new project, few dependencies wont get added to the working directory. Run the below command to get it resolved

npm install --save-dev @angular-devkit/build-angular

Processing $http response in service

As far as caching the response in service is concerned , here's another version that seems more straight forward than what I've seen so far:

App.factory('dataStorage', function($http) {
     var dataStorage;//storage for cache

     return (function() {
         // if dataStorage exists returned cached version
        return dataStorage = dataStorage || $http({
      url: 'your.json',
      method: 'GET',
      cache: true
    }).then(function (response) {

              console.log('if storage don\'t exist : ' + response);

              return response;



this service will return either the cached data or $http.get;

 dataStorage.then(function(data) {
     $ = data;
    console.log('err: ' + e);

Run batch file as a Windows service

Why not simply set it up as a Scheduled Task that is scheduled to run at start up?

Property 'value' does not exist on type EventTarget in TypeScript

The way I do it is the following (better than type assertion imho):

onFieldUpdate(event: { target: HTMLInputElement }) {

This assumes you are only interested in the target property, which is the most common case. If you need to access the other properties of event, a more comprehensive solution involves using the & type intersection operator:

event: Event & { target: HTMLInputElement }

This is a Vue.js version but the concept applies to all frameworks. Obviously you can go more specific and instead of using a general HTMLInputElement you can use e.g. HTMLTextAreaElement for textareas.

identifier "string" undefined?

You want to do #include <string> instead of string.h and then the type string lives in the std namespace, so you will need to use std::string to refer to it.

Filtering a list of strings based on contents

# To support matches from the beginning, not any matches:

items = ['a', 'ab', 'abc', 'bac']
prefix = 'ab'

filter(lambda x: x.startswith(prefix), items)

ORACLE IIF Statement

In PL/SQL, there is a trick to use the undocumented OWA_UTIL.ITE function.


    x   VARCHAR2(10);
    x := owa_util.ite('a' = 'b','T','F');


PL/SQL procedure successfully completed.

What does 'const static' mean in C and C++?

It's a small space optimization.

When you say

const int foo = 42;

You're not defining a constant, but creating a read-only variable. The compiler is smart enough to use 42 whenever it sees foo, but it will also allocate space in the initialized data area for it. This is done because, as defined, foo has external linkage. Another compilation unit can say:

extern const int foo;

To get access to its value. That's not a good practice since that compilation unit has no idea what the value of foo is. It just knows it's a const int and has to reload the value from memory whenever it is used.

Now, by declaring that it is static:

static const int foo = 42;

The compiler can do its usual optimization, but it can also say "hey, nobody outside this compilation unit can see foo and I know it's always 42 so there is no need to allocate any space for it."

I should also note that in C++, the preferred way to prevent names from escaping the current compilation unit is to use an anonymous namespace:

namespace {
    const int foo = 42; // same as static definition above

Implements vs extends: When to use? What's the difference?

Implements is used for Interfaces and extends is used to extend a class.

To make it more clearer in easier terms,an interface is like it sound - an interface - a model, that you need to apply,follow, along with your ideas to it.

Extend is used for classes,here,you are extending something that already exists by adding more functionality to it.

A few more notes:

an interface can extend another interface.

And when you need to choose between implementing an interface or extending a class for a particular scenario, go for implementing an interface. Because a class can implement multiple interfaces but extend only one class.

Producer/Consumer threads using a Queue

Java 5+ has all the tools you need for this kind of thing. You will want to:

  1. Put all your Producers in one ExecutorService;
  2. Put all your Consumers in another ExecutorService;
  3. If necessary, communicate between the two using a BlockingQueue.

I say "if necessary" for (3) because from my experience it's an unnecessary step. All you do is submit new tasks to the consumer executor service. So:

final ExecutorService producers = Executors.newFixedThreadPool(100);
final ExecutorService consumers = Executors.newFixedThreadPool(100);
while (/* has more work */) {
producers.awaitTermination(Long.MAX_VALUE, TimeUnit.NANOSECONDS);
consumers.awaitTermination(Long.MAX_VALUE, TimeUnit.NANOSECONDS);

So the producers submit directly to consumers.

TNS Protocol adapter error while starting Oracle SQL*Plus

Another possibility (esp. with multiple Oracle homes)


sqlplus /nolog

conn / as sysdba;

Cannot ignore .idea/workspace.xml - keeps popping up

The way i did in Android Studio which is also based on IntelliJ was like this. In commit dialog, I reverted the change for workspace.xml, then it was moved to unversioned file. After that I deleted this from commit dialog. Now it won't appear in the changelist. Note that my gitignore was already including .idea/workspace.xml

pip: no module named _internal

Its probably due to a version conflict, try to run this, it will remove the older pip somehow.

sudo apt remove python pip

Bootstrap: Use .pull-right without having to hardcode a negative margin-top

Keep the h2 at the top, then pull-left on the p and pull-right on the login-box

<div class='container'>
  <div class='hero-unit'>


    <div class="pull-left">
      <p>Please log in</p>

    <div id='login-box' class='pull-right control-group'>
        <div class='clearfix'>
            <input type='text' placeholder='Username' />
        <div class='clearfix'>
            <input type='password' placeholder='Password' />
        <button type='button' class='btn btn-primary'>Log in</button>

    <div class="clearfix"></div>


the default vertical-align on floated boxes is baseline, so the "Please log in" exactly lines up with the "Username" (check by changing the pull-right to pull-left).

Excel VBA Run Time Error '424' object required

The first code line, Option Explicit means (in simple terms) that all of your variables have to be explicitly declared by Dim statements. They can be any type, including object, integer, string, or even a variant.

This line: Dim envFrmwrkPath As Range is declaring the variable envFrmwrkPath of type Range. This means that you can only set it to a range.

This line: Set envFrmwrkPath = ActiveSheet.Range("D6").Value is attempting to set the Range type variable to a specific Value that is in cell D6. This could be a integer or a string for example (depends on what you have in that cell) but it's not a range.

I'm assuming you want the value stored in a variable. Try something like this:

Dim MyVariableName As Integer
MyVariableName = ActiveSheet.Range("D6").Value

This assumes you have a number (like 5) in cell D6. Now your variable will have the value.

For simplicity sake of learning, you can remove or comment out the Option Explicit line and VBA will try to determine the type of variables at run time.

Try this to get through this part of your code

Dim envFrmwrkPath As String
Dim ApplicationName As String
Dim TestIterationName As String

Extracting the top 5 maximum values in excel

Put the data into a Pivot Table and do a top n filter on it

Excel Demo

assign value using linq

Be aware that it only updates the first company it found with company id 1. For multiple

 (from c in listOfCompany where == 1 select c).First().Name = "Whatever Name";

For Multiple updates

 from c in listOfCompany where == 1 select c => {c.Name = "Whatever Name";  return c;}

html tables & inline styles

This should do the trick:

<table width="400" border="0" cellpadding="0" cellspacing="0">
    <td width="50" height="40" valign="top" rowspan="3">
      <img alt="" src="" width="40" height="40" style="margin: 0; border: 0; padding: 0; display: block;">
    <td width="350" height="40" style="font-family: Helvetica, Arial, sans-serif; font-size: 14px; color: #000000;">
<a href="" style="color: #D31145; font-weight: bold; text-decoration: none;">LAST FIRST</a><br>
REALTOR | P 123.456.789
    <td width="350" height="70" valign="bottom" style="font-family: Helvetica, Arial, sans-serif; font-size: 14px; color: #000000;">
<img alt="" src="" width="200" height="60" style="margin: 0; border: 0; padding: 0; display: block;">
    <td width="350" height="20" valign="bottom" style="font-family: Helvetica, Arial, sans-serif; font-size: 10px; color: #000000;">
all your minor text here | all your minor text here | all your minor text here

UPDATE: Adjusted code per the comments:

After viewing your jsFiddle, an important thing to note about tables is that table cell widths in each additional row all have to be the same width as the first, and all cells must add to the total width of your table.

Here is an example that will NOT WORK:

<table width="600" border="0" cellpadding="0" cellspacing="0">
    <td width="200" bgcolor="#252525">&nbsp;
    <td width="400" bgcolor="#454545">&nbsp;
    <td width="300" bgcolor="#252525">&nbsp;
    <td width="300" bgcolor="#454545">&nbsp;

Although the 2nd row does add up to 600, it (and any additional rows) must have the same 200-400 split as the first row, unless you are using colspans. If you use a colspan, you could have one row, but it needs to have the same width as the cells it is spanning, so this works:

<table width="600" border="0" cellpadding="0" cellspacing="0">
    <td width="200" bgcolor="#252525">&nbsp;
    <td width="400" bgcolor="#454545">&nbsp;
    <td width="600" colspan="2" bgcolor="#353535">&nbsp;

Not a full tutorial, but I hope that helps steer you in the right direction in the future.

Here is the code you are after:

<table width="900" border="0" cellpadding="0" cellspacing="0">
    <td width="57" height="43" valign="top" rowspan="2">
      <img alt="Rashel Adragna" src="" width="47" height="43" style="margin: 0; border: 0; padding: 0; display: block;">
    <td width="843" height="43" style="font-family: Helvetica, Arial, sans-serif; font-size: 14px; color: #000000;">
<a href="" style="color: #D31145; font-weight: bold; text-decoration: none;">RASHEL ADRAGNA</a><br>
REALTOR | P 855.900.24KW
    <td width="843" height="64" valign="bottom" style="font-family: Helvetica, Arial, sans-serif; font-size: 14px; color: #000000;">
<img alt="Zopa Realty Group logo" src="" width="177" height="54" style="margin: 0; border: 0; padding: 0; display: block;">
    <td width="843" colspan="2" height="20" valign="bottom" align="center" style="font-family: Helvetica, Arial, sans-serif; font-size: 10px; color: #000000;">
all your minor text here | all your minor text here | all your minor text here

You'll note that I've added an extra 10px to some of your table cells. This in combination with align/valigns act as padding between your cells. It is a clever way to aviod actually having to add padding, margins or empty padding cells.

select rows in sql with latest date for each ID repeated multiple times

This question has been asked before. Please see this question.

Using the accepted answer and adapting it to your problem you get:

FROM myTable tt
    (SELECT ID, MAX(Date) AS MaxDateTime
    FROM myTable
    GROUP BY ID) groupedtt 
ON tt.ID = groupedtt.ID 
AND tt.Date = groupedtt.MaxDateTime

Terminal Commands: For loop with echo

By using jot:

jot -w "" 1000 1

Binding an enum to a WinForms combo box, and then setting it

The Enum

public enum Status { Active = 0, Canceled = 3 }; 

Setting the drop down values from it

cbStatus.DataSource = Enum.GetValues(typeof(Status));

Getting the enum from the selected item

Status status; 
Enum.TryParse<Status>(cbStatus.SelectedValue.ToString(), out status); 

Resource leak: 'in' is never closed

adding private static Scanner in; does not really fix the problem, it only clears out the warning. Making the scanner static means it remains open forever (or until the class get's unloaded, which nearly is "forever"). The compiler gives you no warning any more, since you told him "keep it open forever". But that is not what you really wanted to, since you should close resources as soon as you don't need them any more.

HTH, Manfred.

How do I overload the [] operator in C#

The [] operator is called an indexer. You can provide indexers that take an integer, a string, or any other type you want to use as a key. The syntax is straightforward, following the same principles as property accessors.

For example, in your case where an int is the key or index:

public int this[int index]
    get => GetValue(index);

You can also add a set accessor so that the indexer becomes read and write rather than just read-only.

public int this[int index]
    get => GetValue(index);
    set => SetValue(index, value);

If you want to index using a different type, you just change the signature of the indexer.

public int this[string index]

How to extract the decision rules from scikit-learn decision-tree?

I needed a more human-friendly format of rules from the Decision Tree. I'm building open-source AutoML Python package and many times MLJAR users want to see the exact rules from the tree.

That's why I implemented a function based on paulkernfeld answer.

def get_rules(tree, feature_names, class_names):
    tree_ = tree.tree_
    feature_name = [
        feature_names[i] if i != _tree.TREE_UNDEFINED else "undefined!"
        for i in tree_.feature

    paths = []
    path = []
    def recurse(node, path, paths):
        if tree_.feature[node] != _tree.TREE_UNDEFINED:
            name = feature_name[node]
            threshold = tree_.threshold[node]
            p1, p2 = list(path), list(path)
            p1 += [f"({name} <= {np.round(threshold, 3)})"]
            recurse(tree_.children_left[node], p1, paths)
            p2 += [f"({name} > {np.round(threshold, 3)})"]
            recurse(tree_.children_right[node], p2, paths)
            path += [(tree_.value[node], tree_.n_node_samples[node])]
            paths += [path]
    recurse(0, path, paths)

    # sort by samples count
    samples_count = [p[-1][1] for p in paths]
    ii = list(np.argsort(samples_count))
    paths = [paths[i] for i in reversed(ii)]
    rules = []
    for path in paths:
        rule = "if "
        for p in path[:-1]:
            if rule != "if ":
                rule += " and "
            rule += str(p)
        rule += " then "
        if class_names is None:
            rule += "response: "+str(np.round(path[-1][0][0][0],3))
            classes = path[-1][0][0]
            l = np.argmax(classes)
            rule += f"class: {class_names[l]} (proba: {np.round(100.0*classes[l]/np.sum(classes),2)}%)"
        rule += f" | based on {path[-1][1]:,} samples"
        rules += [rule]
    return rules

The rules are sorted by the number of training samples assigned to each rule. For each rule, there is information about the predicted class name and probability of prediction for classification tasks. For the regression task, only information about the predicted value is printed.


from sklearn import datasets
from sklearn.tree import DecisionTreeRegressor
from sklearn import tree

# Prepare the data data
boston = datasets.load_boston()
X =
y =

# Fit the regressor, set max_depth = 3
regr = DecisionTreeRegressor(max_depth=3, random_state=1234)
model =, y)

# Print rules
rules = get_rules(regr, boston.feature_names, None)
for r in rules:

The printed rules:

if (RM <= 6.941) and (LSTAT <= 14.4) and (DIS > 1.385) then response: 22.905 | based on 250 samples
if (RM <= 6.941) and (LSTAT > 14.4) and (CRIM <= 6.992) then response: 17.138 | based on 101 samples
if (RM <= 6.941) and (LSTAT > 14.4) and (CRIM > 6.992) then response: 11.978 | based on 74 samples
if (RM > 6.941) and (RM <= 7.437) and (NOX <= 0.659) then response: 33.349 | based on 43 samples
if (RM > 6.941) and (RM > 7.437) and (PTRATIO <= 19.65) then response: 45.897 | based on 29 samples
if (RM <= 6.941) and (LSTAT <= 14.4) and (DIS <= 1.385) then response: 45.58 | based on 5 samples
if (RM > 6.941) and (RM <= 7.437) and (NOX > 0.659) then response: 14.4 | based on 3 samples
if (RM > 6.941) and (RM > 7.437) and (PTRATIO > 19.65) then response: 21.9 | based on 1 samples

I've summarized the ways to extract rules from the Decision Tree in my article: Extract Rules from Decision Tree in 3 Ways with Scikit-Learn and Python.

Android Emulator: Installation error: INSTALL_FAILED_VERSION_DOWNGRADE

It may be a problem with the Google Play Services dependencies rather than an actual app version issue.

Sometimes, it is NOT the case that:

a) there is an existing version of the app installed, newer or not b) there is an existing version of the app installed on another user account on the device

So the error message is just bogus.

In my case, I had:

implementation ''
implementation ''
implementation ''

But when I tried

implementation ''
implementation ''
implementation ''

I got androidX related errors, as I had not yet upgraded to androidX and was not ready to do so. I found that using the latest 16.x.y versions work and I don't get the error message any more. Furthermore, I could wait till later when I am ready, to upgrade to androidX.

implementation ''
implementation ''
implementation ''

Fastest way to download a GitHub project

I agree with the current answers, I just wanna add little more information, Here's a good functionality

if you want to require just zip file but the owner has not prepared a zip file,

To simply download a repository as a zip file: add the extra path /zipball/master/ to the end of the repository URL, This will give you a full ZIP file

For example, here is your repository

Add zipball/master/ in your repository link

Paste the URL into your browser and it will give you a zip file to download

How do I fix a merge conflict due to removal of a file in a branch?

The conflict message:

CONFLICT (delete/modify): res/layout/dialog_item.xml deleted in dialog and modified in HEAD

means that res/layout/dialog_item.xml was deleted in the 'dialog' branch you are merging, but was modified in HEAD (in the branch you are merging to).

So you have to decide whether

  • remove file using "git rm res/layout/dialog_item.xml"


  • accept version from HEAD (perhaps after editing it) with "git add res/layout/dialog_item.xml"

Then you finalize merge with "git commit".

Note that git will warn you that you are creating a merge commit, in the (rare) case where it is something you don't want. Probably remains from the days where said case was less rare.

How to POST JSON request using Apache HttpClient?

For Apache HttpClient 4.5 or newer version:

    CloseableHttpClient httpclient = HttpClients.createDefault();
    HttpPost httpPost = new HttpPost("http://targethost/login");
    String JSON_STRING="";
    HttpEntity stringEntity = new StringEntity(JSON_STRING,ContentType.APPLICATION_JSON);
    CloseableHttpResponse response2 = httpclient.execute(httpPost);


1 in order to make the code compile, both httpclient package and httpcore package should be imported.

2 try-catch block has been ommitted.

Reference: appache official guide

the Commons HttpClient project is now end of life, and is no longer being developed. It has been replaced by the Apache HttpComponents project in its HttpClient and HttpCore modules Date without time

I almost always use the standard formating ShortDateString, because I want the user to be in control of the actual output of the date.


   Dim d As DateTime = Now


Wednesday, December 10, 2008

Note that these results will vary depending on the culture settings on your computer.

Why does SSL handshake give 'Could not generate DH keypair' exception?

You can disable DHE completely in your jdk, edit jre/lib/security/ and make sure DHE is disabled, eg. like

jdk.tls.disabledAlgorithms=SSLv3, DHE.

Remove unwanted parts from strings in a column

Try this using regular expression:

import re
data['result'] = data['result'].map(lambda x: re.sub('[-+A-Za-z]',x)

Force unmount of NFS-mounted directory

I had the same problem, and neither umount /path -f, neither umount.nfs /path -f, neither fuser -km /path, works

finally I found a simple solution >.<

sudo /etc/init.d/nfs-common restart, then lets do the simple umount ;-)

Python, Pandas : write content of DataFrame into text File

Late to the party: Try this>

base_filename = 'Values.txt'
with open(os.path.join(WorkingFolder, base_filename),'w') as outfile:
#Neatly allocate all columns and rows to a .txt file

Trying to fire the onload event on script tag

You should set the src attribute after the onload event, f.ex:

el.onload = function() { //...
el.src = script;

You should also append the script to the DOM before attaching the onload event:

el.onload = function() { //...
el.src = script;

Remember that you need to check readystate for IE support. If you are using jQuery, you can also try the getScript() method:

How can I add raw data body to an axios request?

How about using direct axios API?

  method: 'post',
  url: baseUrl + 'applications/' + appName + '/dataexport/plantypes' + plan,
  headers: {}, 
  data: {
    foo: 'bar', // This is the body part

Source: axios api

Correct way to add external jars (lib/*.jar) to an IntelliJ IDEA project

I use this method and it works well:

1- Copy And paste the .jar files under the libs folder.

2- Add compile fileTree(dir: 'libs', include: '*.jar') to dependencies in build.gradle then all the jars in the libs folder will be included..

3- Right click on libs folder and select 'Add as library' option from the list.

function to remove duplicate characters in a string

Question: Remove Duplicate characters in a string Method 1 :(Python)

import collections

a = "GiniGinaProtijayi"

aa = collections.OrderedDict().fromkeys(a)

Method 2 :(Python)

a = "GiniGinaProtijayi"
list = []
aa = [ list.append(ch) for ch in a if  ch  not in list]
print( ''.join(list))

IN Java:

class test2{
    public static void main(String[] args) {

 String a = "GiniGinaProtijayi";
 List<Character> list = new ArrayList<>();

       for(int i = 0 ; i < a.length() ;i++) {
           char ch = a.charAt(i);
           if( list.size() == 0 ) {list.add(ch);}
           if(!list.contains(ch)) {list.add(ch) ;}

       StringBuffer sbr = new StringBuffer();

      for( char ch : list) {sbr.append(ch);}



form_for with nested resources

Travis R is correct. (I wish I could upvote ya.) I just got this working myself. With these routes:

resources :articles do
  resources :comments

You get paths like:


routed to controllers at


just as it says at, with no special namespaces.

But partials and forms become tricky. Note the square brackets:

<%= form_for [@article, @comment] do |f| %>

Most important, if you want a URI, you may need something like this:

article_comment_path(@article, @comment)


[@article, @comment]

as described at

For example, inside a collections partial with comment_item supplied for iteration,

<%= link_to "delete", article_comment_path(@article, comment_item),
      :method => :delete, :confirm => "Really?" %>

What jamuraa says may work in the context of Article, but it did not work for me in various other ways.

There is a lot of discussion related to nested resources, e.g.

Interestingly, I just learned that most people's unit-tests are not actually testing all paths. When people follow jamisbuck's suggestion, they end up with two ways to get at nested resources. Their unit-tests will generally get/post to the simplest:

# POST /comments
post :create, :comment => {:article_id=>42, ...}

In order to test the route that they may prefer, they need to do it this way:

# POST /articles/42/comments
post :create, :article_id => 42, :comment => {...}

I learned this because my unit-tests started failing when I switched from this:

resources :comments
resources :articles do
  resources :comments

to this:

resources :comments, :only => [:destroy, :show, :edit, :update]
resources :articles do
  resources :comments, :only => [:create, :index, :new]

I guess it's ok to have duplicate routes, and to miss a few unit-tests. (Why test? Because even if the user never sees the duplicates, your forms may refer to them, either implicitly or via named routes.) Still, to minimize needless duplication, I recommend this:

resources :comments
resources :articles do
  resources :comments, :only => [:create, :index, :new]

Sorry for the long answer. Not many people are aware of the subtleties, I think.

How to escape single quotes in MySQL

$var = mysqli_real_escape_string($conn, $_POST['varfield']);

Can I call jQuery's click() to follow an <a> link if I haven't bound an event handler to it with bind or click already?

To open hyperlink in the same tab, use:

$(document).on('click', "a.classname", function() {
    var form = $("<form></form>");
        id     : "formid",
        action : $(this).attr("href"),
        method : "GET",

    return false;

IN vs ANY operator in PostgreSQL

(Neither IN nor ANY is an "operator". A "construct" or "syntax element".)

Logically, quoting the manual:

IN is equivalent to = ANY.

But there are two syntax variants of IN and two variants of ANY. Details:

IN taking a set is equivalent to = ANY taking a set, as demonstrated here:

But the second variant of each is not equivalent to the other. The second variant of the ANY construct takes an array (must be an actual array type), while the second variant of IN takes a comma-separated list of values. This leads to different restrictions in passing values and can also lead to different query plans in special cases:

ANY is more versatile

The ANY construct is far more versatile, as it can be combined with various operators, not just =. Example:

SELECT 'foo' LIKE ANY('{FOO,bar,%oo%}');

For a big number of values, providing a set scales better for each:


Inversion / opposite / exclusion

"Find rows where id is in the given array":

SELECT * FROM tbl WHERE id = ANY (ARRAY[1, 2]);

Inversion: "Find rows where id is not in the array":

SELECT * FROM tbl WHERE id <> ALL (ARRAY[1, 2]);
SELECT * FROM tbl WHERE id <> ALL ('{1, 2}');  -- equivalent array literal
SELECT * FROM tbl WHERE NOT (id = ANY ('{1, 2}'));

All three equivalent. The first with array constructor, the other two with array literal. The data type can be derived from context unambiguously. Else, an explicit cast may be required, like '{1,2}'::int[].

Rows with id IS NULL do not pass either of these expressions. To include NULL values additionally:

SELECT * FROM tbl WHERE (id = ANY ('{1, 2}')) IS NOT TRUE;

DataTable: Hide the Show Entries dropdown but keep the Search box

If you're using Angular you can use the following code to do the same.

in component.html

<table id="" datatable [dtOptions]="dtOptions" class="table dataTable">

and in your component.ts

 dtOptions: any = {}

 this.dtOptions = {
  searching: true,    //enables the search bar
  info: false        //disables the entry information

there more option for data table available please visit here to learn more

Java optional parameters

You can use a class that works much like a builder to contain your optional values like this.

public class Options {
    private String someString = "default value";
    private int someInt= 0;
    public Options setSomeString(String someString) {
        this.someString = someString;
        return this;
    public Options setSomeInt(int someInt) {
        this.someInt = someInt;
        return this;

public static void foo(Consumer<Options> consumer) {
    Options options = new Options();
    System.out.println("someString = " + options.someString + ", someInt = " + options.someInt);

Use like

foo(o -> o.setSomeString("something").setSomeInt(5));

Output is

someString = something, someInt = 5

To skip all the optional values you'd have to call it like foo(o -> {}); or if you prefer, you can create a second foo() method that doesn't take the optional parameters.

Using this approach, you can specify optional values in any order without any ambiguity. You can also have parameters of different classes unlike with varargs. This approach would be even better if you can use annotations and code generation to create the Options class.

Meaning of "n:m" and "1:n" in database design

Many to Many (n:m) One to Many (1:n)

Where is the .NET Framework 4.5 directory?

The webpage is incorrect and I have pointed this out to MS and they will get it changed.

As already stated above .NET 4.5 is an in-place upgrade of 4.0 so you will only have Microsoft.NET\Framework\v4.0.30319.

The ToolVersion for MSBuild remains at "4.0".

How to get data from database in javascript based on the value passed to the function

Try the following:

 //Functions to open database and to create, insert data into tables

 getSelectedRow = function(val)
        db.transaction(function(transaction) {
              transaction.executeSql('SELECT * FROM Employ where number = ?;',[parseInt(val)], selectedRowValues, errorHandler);

    selectedRowValues = function(transaction,results)
         for(var i = 0; i < results.rows.length; i++)
             var row = results.rows.item(i);

You don't have access to javascript variable names in SQL, you must pass the values to the Database.

How return error message in spring mvc @Controller

Evaluating the error response from another service invocated...

This was my solution for evaluating the error:

try {
        return authenticationFeign.signIn(userDto, dataRequest);
    }catch(FeignException ex){


        if(ex.status() == HttpStatus.UNAUTHORIZED.value()){
            System.out.println("is a error 401");
            return new ResponseEntity<>(HttpStatus.UNAUTHORIZED);
        return new ResponseEntity<>(HttpStatus.OK);


Find closing HTML tag in Sublime Text

As said before, Control/Command + Shift + A gives you basic support for tag matching. Press it again to extend the match to the parent element. Press arrow left/right to jump to the start/end tag.

Anyway, there is no built-in highlighting of matching tags. Emmet is a popular plugin but it's overkill for this purpose and can get in the way if you don't want Emmet-like editing. Bracket Highlighter seems to be a better choice for this use case.

How can you create pop up messages in a batch script?

Few more ways (in all of them the script waits for button pressing unlike msg.exe).

1) The geekiest and hackiest - it uses the IEXPRESS to create small exe that will create a pop-up with a single button (it can create two more types of pop-up messages).Works on EVERY windows from XP and above:

;@echo off

;set ppopup_executable=popupe.exe
;set "message2=click OK to continue"
;del /q /f %tmp%\yes >nul 2>&1
;copy /y "%~f0" "%temp%\popup.sed" >nul 2>&1

;iexpress /n /q /m %temp%\popup.sed
;rem del /q /f %ppopup_executable% >nul 2>&1


;exit /b 0



2) Using MSHTA. Also works on every windows machine from XP and above (despite yhe OP do not wants "external" languages the jsvascript here is minimized).Should be saved as .bat:

@if (true == false) @end /*!
@echo off
mshta "about:<script src='file://%~f0'></script><script>close()</script>" %*
goto :EOF */

alert("Hello, world!");

or in one line:

mshta "about:<script>alert('Hello, world!');close()</script>"


mshta "javascript:alert('message');close()"


mshta.exe vbscript:Execute("msgbox ""message"",0,""title"":close")

3) Here's parametrized .bat/jscript hybrid (should be saved as bat) .It again uses jscript despite the OP request but as it is a bat it can be called as a bat file without worries.It uses POPUP which allows a little bit more control than the more populae MSGBOX.It uses WSH ,but not MSHTA like in the example above.

 @if (@x)==(@y) @end /***** jscript comment ******
     @echo off

     cscript //E:JScript //nologo "%~f0" "%~nx0" %*
     exit /b 0

 @if (@x)==(@y) @end ******  end comment *********/

var wshShell = WScript.CreateObject("WScript.Shell");
var args=WScript.Arguments;
var title=args.Item(0);

var timeout=-1;
var pressed_message="button pressed";
var timeout_message="timedout";
var message="";

function printHelp() {
    WScript.Echo(title + "[-title Title] [-timeout m] [-tom \"Time-out message\"] [-pbm \"Pressed button message\"]  [-message \"pop-up message\"]");

if (WScript.Arguments.Length==1){

if (args.Item(1).toLowerCase() == "-help" ||  args.Item(1).toLowerCase() == "-h" ) {

if (WScript.Arguments.Length % 2 == 0 ) {
    WScript.Echo("Illegal arguments ");

for (var arg = 1 ; arg<args.Length;arg=arg+2) {

    if (args.Item(arg).toLowerCase() == "-title") {
        title = args.Item(arg+1);

    if (args.Item(arg).toLowerCase() == "-timeout") {
        timeout = parseInt(args.Item(arg+1));
        if (isNaN(timeout)) {

    if (args.Item(arg).toLowerCase() == "-tom") {
        timeout_message = args.Item(arg+1);

    if (args.Item(arg).toLowerCase() == "-pbm") {
        pressed_message = args.Item(arg+1);

    if (args.Item(arg).toLowerCase() == "-message") {
        message = args.Item(arg+1);

function runPopup(){
    var btn = wshShell.Popup(message, timeout, title, 0x0 + 0x10);

    switch(btn) {
        // button pressed.
        case 1:

        // Timed out.
        case -1:


4) and one hybrid (should be saved as .bat) .This time it uses .NET and compiles a small .exe file that could be deleted:

@if (@X)==(@Y) @end /****** silent jscript comment ******

@echo off
:::       compile the script    ::::

::if exist "%~n0.exe" goto :skip_compilation

:: searching the latest installed .net framework
for /f "tokens=* delims=" %%v in ('dir /b /s /a:d /o:-n "%SystemRoot%\Microsoft.NET\Framework\v*"') do (
    if exist "%%v\jsc.exe" (
        rem :: the compiler
        set "jsc=%%~dpsnfxv\jsc.exe"
        goto :break_loop
echo jsc.exe not found && exit /b 0

call %jsc% /nologo /out:"%~n0.exe" "%~f0" 
:::       end of compilation    ::::

"%~n0.exe" %*
exit /b 0

****** end of jscript comment ******/

import System;
import System.WIndows;
import System.Windows.Forms

var arguments:String[] = Environment.GetCommandLineArgs();

5) and at the end one single call to powershell that creates a pop-up (can be called from command line or from batch if powershell is installed):

powershell [Reflection.Assembly]::LoadWithPartialName("""System.Windows.Forms""");[Windows.Forms.MessageBox]::show("""Hello World""", """My PopUp Message Box""")

6) Though msg solution is already post as answer here's a better way to be used:

msg * /self /w "hello world"

/self is a not documented switch that will force msg to send the message only to the current user.

Strip all non-numeric characters from string in JavaScript



var myString = 'abc123.8<blah>'_x000D_
console.log( myString.match(/\d/g).join`` );

Your project contains error(s), please fix it before running it

If none of the above solution work, you should check the READ ONLY property of the Project folder, if it is Read-Only, the compiler will not be able to overwrite the resources, and other dex APK etc files and hence this will occur.. This happened to me and I fixed after a long struggle.. Happy Programming.

HTTP vs HTTPS performance

The HTTPS indeed affects page speed...

The quotes above reveal the foolishness of many people about site security and speed. HTTPS / SSL server handshaking creates an initial stall in making Internet connections. There’s a slow delay before anything starts to render on your visitor’s browser screen. This delay is measured in Time-to-First-Byte information.

HTTPS handshake overhead appears in Time-to-First-Byte information (TTFB). Common TTFB ranges from under 100 milliseconds (best-case) to over 1.5 seconds (worst case). But, of course, with HTTPS it’s 500 milliseconds worse.

Roundtrip, wireless 3G connections can be 500 milliseconds or more. The extra trips double delays to 1 second or more. This is a big, negative impact on mobile performance. Very bad news.

My advice, if you're not exchanging sensitive data then you don't need SSL at all, but if you do like an ecommerce website then you can just enable HTTPS on certain pages where sensitive data is exchanged like Login and checkout.

Source: Pagepipe

TextView - setting the text size programmatically doesn't seem to work

Currently, setTextSize(float size) method will work well so we don't need to use another method for change text size source code

 * Set the default text size to the given value, interpreted as "scaled
 * pixel" units.  This size is adjusted based on the current density and
 * user font size preference.
 * <p>Note: if this TextView has the auto-size feature enabled than this function is no-op.
 * @param size The scaled pixel size.
 * @attr ref android.R.styleable#TextView_textSize
public void setTextSize(float size) {
    setTextSize(TypedValue.COMPLEX_UNIT_SP, size);

Example using

textView.setTextSize(20); // set your text size = 20sp

Most efficient way to append arrays in C#?

If you can make an approximation of the number of items that will be there at the end, use the overload of the List constuctor that takes count as a parameter. You will save some expensive List duplications. Otherwise you have to pay for it.

How can I compile and run c# program without using visual studio?

I use a batch script to compile and run C#:

C:\Windows\Microsoft.NET\Framework\v4.0.30319\csc /out:%1 %2

@echo off

if errorlevel 1 (

start %1 %1

I call it like this:

C:\bin\csc.bat "C:\code\MyProgram.exe" "C:\code\MyProgram.cs"

I also have a shortcut in Notepad++, which you can define by going to Run > Run...:


I assigned this shortcut to my F5 key for maximum laziness.

How to match all occurrences of a regex

To find all the matching strings, use String's scan method.

str = "A 54mpl3 string w1th 7 numb3rs scatter36 ar0und"
#=> ["54", "3", "1", "7", "3", "36", "0"]

If you want, MatchData, which is the type of the object returned by the Regexp match method, use:

str.to_enum(:scan, /\d+/).map { Regexp.last_match }
#=> [#<MatchData "54">, #<MatchData "3">, #<MatchData "1">, #<MatchData "7">, #<MatchData "3">, #<MatchData "36">, #<MatchData "0">]

The benefit of using MatchData is that you can use methods like offset:

match_datas = str.to_enum(:scan, /\d+/).map { Regexp.last_match }
#=> [2, 4]
#=> [7, 8]

See these questions if you'd like to know more:

Reading about special variables $&, $', $1, $2 in Ruby will be helpful too.

Access non-numeric Object properties by index?

"I'm specifically looking to target the index, just like the first example - if it's possible."

No, it isn't possible.

The closest you can get is to get an Array of the object's keys, and use that:

var keys = Object.keys( obj );

...but there's no guarantee that the keys will be returned in the order you defined. So it could end up looking like:

keys[ 0 ];  // 'evenmore'
keys[ 1 ];  // 'something'

Line Break in XML formatting?

If you are refering to res strings, use CDATA with \n.

<string name="about">
 Author: Sergio Abreu\n

Finding diff between current and last version

If last versions means last tag, and current versions means HEAD (current state), it's just a diff with the last tag:

Looking for tags:

$ git tag --list

The last tag would be:

$ git tag --list | tail -n 1

Putting it together:

tag=$(git tag --list | tail -n 1)
git diff $tag

Prevent scrolling of parent element when inner element scroll position reaches top/bottom?

Don't use overflow: hidden; on body. It automatically scrolls everything to the top. There's no need for JavaScript either. Make use of overflow: auto;:

HTML Structure

<div class="overlay">
    <div class="overlay-content"></div>

<div class="background-content">
    lengthy content here


    position: fixed;
    top: 0px;
    left: 0px;
    right: 0px;
    bottom: 0px;
    background-color: rgba(0, 0, 0, 0.8);

    .overlay-content {
        height: 100%;
        overflow: scroll;

    height: 100%;
    overflow: auto;

Play with the demo here.

Create a Path from String in Java7

Even when the question is regarding Java 7, I think it adds value to know that from Java 11 onward, there is a static method in Path class that allows to do this straight away:

With all the path in one String:


With the path broken down in several Strings:


Use Awk to extract substring

I am asking in general, how to write a compatible awk script that performs the same functionality ...

To solve the problem in your quesiton is easy. (check others' answer).

If you want to write an awk script, which portable to any awk implementations and versions (gawk/nawk/mawk...) it is really hard, even if with --posix (gawk)

for example:

  • some awk works on string in terms of characters, some with bytes
  • some supports \x escape, some not
  • FS interpreter works differently
  • keywords/reserved words abbreviation restriction
  • some operator restriction e.g. **
  • even same awk impl. (gawk for example), the version 4.0 and 3.x have difference too.
  • the implementation of certain functions are also different. (your problem is one example, see below)

well all the points above are just spoken in general. Back to your problem, you problem is only related to fundamental feature of awk. awk '{print $x}' the line like that will work all awks.

There are two reasons why your awk line behaves differently on gawk and mawk:

  • your used substr() function wrongly. this is the main cause. you have substr($0, 0, RSTART - 1) the 0 should be 1, no matter which awk do you use. awk array, string idx etc are 1-based.

  • gawk and mawk implemented substr() differently.

How can I initialise a static Map?

If you want unmodifiable map, finally java 9 added a cool factory method of to Map interface. Similar method is added to Set, List as well.

Map<String, String> unmodifiableMap = Map.of("key1", "value1", "key2", "value2");

Setting a property by reflection with a string value

I will answer this with a general answer. Usually these answers not working with guids. Here is a working version with guids too.

var stringVal="6e3ba183-89d9-e611-80c2-00155dcfb231"; // guid value as string to set
var prop = obj.GetType().GetProperty("FooGuidProperty"); // property to be setted
var propType = prop.PropertyType;

// var will be type of guid here
var valWithRealType = TypeDescriptor.GetConverter(propType).ConvertFrom(stringVal); 

HTML Mobile -forcing the soft keyboard to hide

Since the soft keyboard is part of the OS, more often than not, you won't be able to hide it - also, on iOS, hiding the keyboard drops focus from the element.

However, if you use the onFocus attribute on the input, and then blur() the text input immediately, the keyboard will hide itself and the onFocus event can set a variable to define which text input was focused last.

Then alter your on-page keyboard to only alter the last-focused (check using the variable) text input, rather than simulating a key press.

How to check if user input is not an int value

Maybe you can try this:

int function(){
Scanner input = new Scanner(;   
System.out.print("Enter an integer between 1-100: ");   
int range;
    range = input.nextInt();
    if(0<=range && range <= 100)
    input.nextLine();  //Comsume the garbage value
    System.out.println("Enter an integer between 1-100:");
return range;

Spring - No EntityManager with actual transaction available for current thread - cannot reliably process 'persist' call

I had the same error code when I used @Transaction on a wrong method/actionlevel.

methodWithANumberOfDatabaseActions() { 
   methodA( ...)
   methodA( ...)

void methodA( ...) {
  ... ERROR message

I had to place the @Transactional just above the method methodWithANumberOfDatabaseActions(), of course.

That solved the error message in my case.

Can you hide the controls of a YouTube embed without enabling autoplay?

Set autoplay=0

<iframe width="100%" height="100%" src="//" frameborder="0" allowfullscreen>

As seen here: Autoplay=0 Test

CSS animation delay in repeating

I know this is old but I was looking for the answer in this post and with jquery you can do it easily and without too much hassle. Just declare your animation keyframe in the css and set the class with the atributes you would like. I my case I used the tada animation from css animate:

.tada {
    -webkit-animation-name: tada;
    animation-name: tada;
    -webkit-animation-duration: 1.25s;
    animation-duration: 1.25s;
    -webkit-animation-fill-mode: both;
    animation-fill-mode: both;

I wanted the animation to run every 10 seconds so jquery just adds the class, after 6000ms (enough time for the animation to finish) it removes the class and 4 seconds later it adds the class again and so the animation starts again.

$(document).ready(function() {
  setInterval(function() {

    $(".bottom h2").addClass("tada");//adds the class

    setTimeout(function() {//waits 6 seconds to remove the class
      $(".bottom h2").removeClass("tada");
    }, 6000);

  }, 10000)//repeats the process every 10 seconds

Not at all difficult like one guy posted.

How to pass anonymous types as parameters?

Instead of passing an anonymous type, pass a List of a dynamic type:

  1. var dynamicResult = anonymousQueryResult.ToList<dynamic>();
  2. Method signature: DoSomething(List<dynamic> _dynamicResult)
  3. Call method: DoSomething(dynamicResult);
  4. done.

Thanks to Petar Ivanov!

OpenSSL and error in reading openssl.conf file

If you are seeing an error something like

error on line -1 c:apacheconfopenssl.cnf

try changing from back slash to front slash in the -config.

Adding an assets folder in Android Studio

You can click on the Project window, press Alt-Insert, and select Folder->Assets Folder. Android Studio will add it automatically to the correct location.

You are most likely looking at your Project with the new(ish) "Android View". Note that this is a view and not the actual folder structure on disk (which hasn't changed since the introduction of Gradle as the new build tool). You can switch to the old "Project View" by clicking on the word "Android" at the top of the Project window and selecting "Project".

Using CMake with GNU Make: How can I see the exact commands?

Or simply export VERBOSE environment variable on the shell like this: export VERBOSE=1

How to set caret(cursor) position in contenteditable element (div)?

I think it's not simple to set caret to some position in contenteditable element. I wrote my own code for this. It bypasses the node tree calcing how many characters left and sets caret in needed element. I didn't test this code much.

//Set offset in current contenteditable field (for start by default or for with forEnd=true)
function setCurSelectionOffset(offset, forEnd = false) {
    const sel = window.getSelection();
    if (sel.rangeCount !== 1 || !document.activeElement) return;

    const firstRange = sel.getRangeAt(0);

    if (offset > 0) {
        bypassChildNodes(document.activeElement, offset);
        if (forEnd)
            firstRange.setEnd(document.activeElement, 0);
            firstRange.setStart(document.activeElement, 0);

    //Bypass in depth
    function bypassChildNodes(el, leftOffset) {
        const childNodes = el.childNodes;

        for (let i = 0; i < childNodes.length && leftOffset; i++) {
            const childNode = childNodes[i];

            if (childNode.nodeType === 3) {
                const curLen = childNode.textContent.length;

                if (curLen >= leftOffset) {
                    if (forEnd)
                        firstRange.setEnd(childNode, leftOffset);
                        firstRange.setStart(childNode, leftOffset);
                    return 0;
                    leftOffset -= curLen;
            if (childNode.nodeType === 1) {
                leftOffset = bypassChildNodes(childNode, leftOffset);

        return leftOffset;

I also wrote code to get current caret position (didn't test):

//Get offset in current contenteditable field (start offset by default or end offset with calcEnd=true)
function getCurSelectionOffset(calcEnd = false) {
    const sel = window.getSelection();
    if (sel.rangeCount !== 1 || !document.activeElement) return 0;

    const firstRange     = sel.getRangeAt(0),
          startContainer = calcEnd ? firstRange.endContainer : firstRange.startContainer,
          startOffset    = calcEnd ? firstRange.endOffset    : firstRange.startOffset;
    let needStop = false;

    return bypassChildNodes(document.activeElement);

    //Bypass in depth
    function bypassChildNodes(el) {
        const childNodes = el.childNodes;
        let ans = 0;

        if (el === startContainer) {
            if (startContainer.nodeType === 3) {
                ans = startOffset;
            if (startContainer.nodeType === 1) {
                for (let i = 0; i < startOffset; i++) {
                    const childNode = childNodes[i];

                    ans += childNode.nodeType === 3 ? childNode.textContent.length :
                           childNode.nodeType === 1 ? childNode.innerText.length :

            needStop = true;
            for (let i = 0; i < childNodes.length && !needStop; i++) {
                const childNode = childNodes[i];
                ans += bypassChildNodes(childNode);

        return ans;

You also need to be aware of range.startOffset and range.endOffset contain character offset for text nodes (nodeType === 3) and child node offset for element nodes (nodeType === 1). range.startContainer and range.endContainer may refer to any element node of any level in the tree (of course they also can refer to text nodes).

What are -moz- and -webkit-?

These are the vendor-prefixed properties offered by the relevant rendering engines (-webkit for Chrome, Safari; -moz for Firefox, -o for Opera, -ms for Internet Explorer). Typically they're used to implement new, or proprietary CSS features, prior to final clarification/definition by the W3.

This allows properties to be set specific to each individual browser/rendering engine in order for inconsistencies between implementations to be safely accounted for. The prefixes will, over time, be removed (at least in theory) as the unprefixed, the final version, of the property is implemented in that browser.

To that end it's usually considered good practice to specify the vendor-prefixed version first and then the non-prefixed version, in order that the non-prefixed property will override the vendor-prefixed property-settings once it's implemented; for example:

.elementClass {
    -moz-border-radius: 2em;
    -ms-border-radius: 2em;
    -o-border-radius: 2em;
    -webkit-border-radius: 2em;
    border-radius: 2em;

Specifically, to address the CSS in your question, the lines you quote:

-webkit-column-count: 3;
-webkit-column-gap: 10px;
-webkit-column-fill: auto;
-moz-column-count: 3;
-moz-column-gap: 10px;
-moz-column-fill: auto;

Specify the column-count, column-gap and column-fill properties for Webkit browsers and Firefox.


Equivalent of explode() to work with strings in MySQL

Use this function. It works like a charm. replace "|" with the char to explode/split and the values 1,2,3,etc are based on the number of entries in the data-set: Value_ONE|Value_TWO|Value_THREE.


I hope this helps.

Electron: jQuery is not defined

im building and Angular App with electron, my solution was the following:


    if ( typeof module === "object" && typeof module.exports === "object" ) {
      window.$ = window.jQuery = require('jquery');


"scripts": [

So Jquery gets loaded from angular.json if on browser, else if it is an electron builded app it will require module instead.

If you want to import jquery in index.html instead of importing from angular.json use the following solution:

<script src="path/to/jquery"></script>
    if ( typeof module === "object" && typeof module.exports === "object" ) {
      window.$ = window.jQuery = require('jquery');

ImportError: No module named PIL

On some installs of PIL, you must do

import Image

instead of import PIL (PIL is in fact not always imported this way). Since import Image works for you, this means that you have in fact installed PIL.

Having a different name for the library and the Python module is unusual, but this is what was chosen for (some versions of) PIL.

You can get more information about how to use this module from the official tutorial.

PS: In fact, on some installs, import PIL does work, which adds to the confusion. This is confirmed by an example from the documentation, as @JanneKarila found out, and also by some more recent versions of the MacPorts PIL package (1.1.7).

Get public/external IP address?

When I debug, I use following to construct the externally callable URL, but you could just use first 2 lines to get your public IP:

public static string ExternalAction(this UrlHelper helper, string actionName, string controllerName = null, RouteValueDictionary routeValues = null, string protocol = null)
    var client = new HttpClient();
    var ipAddress = client.GetStringAsync("").Result; 
    // above 2 lines should do it..
    var route = UrlHelper.GenerateUrl(null, actionName, controllerName, routeValues, helper.RouteCollection, helper.RequestContext, true); 
    if (route == null)
        return route;
    if (string.IsNullOrEmpty(protocol) && string.IsNullOrEmpty(ipAddress))
        return route;
    var url = HttpContext.Current.Request.Url;
    protocol = !string.IsNullOrWhiteSpace(protocol) ? protocol : Uri.UriSchemeHttp;
    return string.Concat(protocol, Uri.SchemeDelimiter, ipAddress, route);
    helper.Action(action, null, null, HttpContext.Current.Request.Url.Scheme)

batch script - run command on each file in directory

Actually this is pretty easy since Windows Vista. Microsoft added the command FORFILES

in your case

forfiles /p c:\directory /m *.xls /c "cmd /c ssconvert @file @fname.xlsx"

the only weird thing with this command is that forfiles automatically adds double quotes around @file and @fname. but it should work anyway

dropping infinite values from dataframes in pandas?

The simplest way would be to first replace infs to NaN:

df.replace([np.inf, -np.inf], np.nan)

and then use the dropna:

df.replace([np.inf, -np.inf], np.nan).dropna(subset=["col1", "col2"], how="all")

For example:

In [11]: df = pd.DataFrame([1, 2, np.inf, -np.inf])

In [12]: df.replace([np.inf, -np.inf], np.nan)
0   1
1   2
2 NaN
3 NaN

The same method would work for a Series.

Git checkout: updating paths is incompatible with switching branches

Could your issue be linked to this other SO question "checkout problem"?

i.e.: a problem related to:

  • an old version of Git
  • a curious checkout syntax, which should be: git checkout -b [<new_branch>] [<start_point>], with [<start_point>] referring to the name of a commit at which to start the new branch, and 'origin/remote-name' is not that.
    (whereas git branch does support a start_point being the name of a remote branch)

Note: what the script says is:

  if test '' != "$newbranch$force$merge"
    die "git checkout: updating paths is incompatible with switching branches/forcing$hint"

It is like the syntax git checkout -b [] [remote_branch_name] was both renaming the branch and resetting the new starting point of the new branch, which is deemed incompatible.

Getting list of files in documents folder

Simple and dynamic solution (Swift 5):

extension FileManager {

  class func directoryUrl() -> URL? {
      let paths = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask)
      return paths.first

  class func allRecordedData() -> [URL]? {
     if let documentsUrl = FileManager.directoryUrl() {
        do {
            let directoryContents = try FileManager.default.contentsOfDirectory(at: documentsUrl, includingPropertiesForKeys: nil)
            return directoryContents.filter{ $0.pathExtension == "m4a" }
        } catch {
            return nil
     return nil

Assign output to variable in Bash

In shell, you don't put a $ in front of a variable you're assigning. You only use $IP when you're referring to the variable.



echo "$IP"

sed "s/IP/$IP/" nsupdate.txt | nsupdate

How to allow http content within an iframe on a https site

You could try scraping whatever you need with PHP or another server side language, then put the iframe to the scraped content. Here's an example with PHP:


$homepage = file_get_contents('');
echo $homepage;


<iframe src="scrapedcontent.php"></iframe>

Can I multiply strings in Java to repeat sequences?

No, but you can in Scala! (And then compile that and run it using any Java implementation!!!!)

Now, if you want to do it the easy way in java, use the Apache commons-lang package. Assuming you're using maven, add this dependency to your pom.xml:


And then use StringUtils.repeat as follows:

import org.apache.commons.lang.StringUtils
someNum = sumNum + StringUtils.repeat("0", 3);

App not setup: This app is still in development mode

Issue Log: App Not Setup. This app is still in development mode. and you dont have access to it. register test user or ask an app admin for permission

  1. The app are not in Live Mode
  2. You are not listed as admin or a tester in
  3. Your App Hashkey are not set. if Facebook app cant be on Live Mode you need a hashkey to test it. because the app are not yet Live. Facebook wont allow an access.

1. go to :
2. select your app on "My Apps" List
3. toggle the switch from OFF to ON

enter image description hereenter image description here

1. go to :
2. select your app on "My Apps" List
3. go to : Roles > Roles > Press Add for example administratorenter image description here 4. Search your new admin/tester Facebook account.
enter image description here 5. admin must enter facebook password to confirm.then submit enter image description here
the new admin must go to developer.facebook page and accept the request
6. go to :

7. Profile > Requests > Confirm
enter image description here List item 8. Congratulation you have been assign as new Admin

as Refer to Facebook Login Documentation
The most preferable solution by me is by code ( Troubleshooting Sample Apps )
it will print out the hash key. you can update it on
on Android > Key Hashes section

a step by step process on how to get the hashKey.

  1. Firstly Add the code to any oncreate method enter image description here

  2. Run The app and Search the KeyHash at Logcat enter image description here

step by step process on how Update on Facebook Developer.

  1. Open Facebook Developer Page. You need access as to update the Facebook Developer page.

  2. Follow the step as follow.enter image description here

VBA Check if variable is empty

To check if a Variant is Null, you need to do it like:

Isnull(myvar) = True


Not Isnull(myvar)

The mysql extension is deprecated and will be removed in the future: use mysqli or PDO instead

  1. Why is this happening?

    The entire ext/mysql PHP extension, which provides all functions named with the prefix mysql_, was officially deprecated in PHP v5.5.0 and removed in PHP v7.

    It was originally introduced in PHP v2.0 (November 1997) for MySQL v3.20, and no new features have been added since 2006. Coupled with the lack of new features are difficulties in maintaining such old code amidst complex security vulnerabilities.

    The manual has contained warnings against its use in new code since June 2011.

  2. How can I fix it?

    As the error message suggests, there are two other MySQL extensions that you can consider: MySQLi and PDO_MySQL, either of which can be used instead of ext/mysql. Both have been in PHP core since v5.0, so if you're using a version that is throwing these deprecation errors then you can almost certainly just start using them right away—i.e. without any installation effort.

    They differ slightly, but offer a number of advantages over the old extension including API support for transactions, stored procedures and prepared statements (thereby providing the best way to defeat SQL injection attacks). PHP developer Ulf Wendel has written a thorough comparison of the features. has an excellent tutorial on migrating from ext/mysql to PDO.

  3. I understand that it's possible to suppress deprecation errors by setting error_reporting in php.ini to exclude E_DEPRECATED:

    error_reporting = E_ALL ^ E_DEPRECATED

    What will happen if I do that?

    Yes, it is possible to suppress such error messages and continue using the old ext/mysql extension for the time being. But you really shouldn't do this—this is a final warning from the developers that the extension may not be bundled with future versions of PHP (indeed, as already mentioned, it has been removed from PHP v7). Instead, you should take this opportunity to migrate your application now, before it's too late.

    Note also that this technique will suppress all E_DEPRECATED messages, not just those to do with the ext/mysql extension: therefore you may be unaware of other upcoming changes to PHP that would affect your application code. It is, of course, possible to only suppress errors that arise on the expression at issue by using PHP's error control operator—i.e. prepending the relevant line with @—however this will suppress all errors raised by that expression, not just E_DEPRECATED ones.

What should you do?

  • You are starting a new project.

    There is absolutely no reason to use ext/mysql—choose one of the other, more modern, extensions instead and reap the rewards of the benefits they offer.

  • You have (your own) legacy codebase that currently depends upon ext/mysql.

    It would be wise to perform regression testing: you really shouldn't be changing anything (especially upgrading PHP) until you have identified all of the potential areas of impact, planned around each of them and then thoroughly tested your solution in a staging environment.

    • Following good coding practice, your application was developed in a loosely integrated/modular fashion and the database access methods are all self-contained in one place that can easily be swapped out for one of the new extensions.

      Spend half an hour rewriting this module to use one of the other, more modern, extensions; test thoroughly. You can later introduce further refinements to reap the rewards of the benefits they offer.

    • The database access methods are scattered all over the place and cannot easily be swapped out for one of the new extensions.

      Consider whether you really need to upgrade to PHP v5.5 at this time.

      You should begin planning to replace ext/mysql with one of the other, more modern, extensions in order that you can reap the rewards of the benefits they offer; you might also use it as an opportunity to refactor your database access methods into a more modular structure.

      However, if you have an urgent need to upgrade PHP right away, you might consider suppressing deprecation errors for the time being: but first be sure to identify any other deprecation errors that are also being thrown.

  • You are using a third party project that depends upon ext/mysql.

    Consider whether you really need to upgrade to PHP v5.5 at this time.

    Check whether the developer has released any fixes, workarounds or guidance in relation to this specific issue; or, if not, pressure them to do so by bringing this matter to their attention. If you have an urgent need to upgrade PHP right away, you might consider suppressing deprecation errors for the time being: but first be sure to identify any other deprecation errors that are also being thrown.

    It is absolutely essential to perform regression testing.

How to set a class attribute to a Symfony2 form input

You can do it with FormBuilder. Add this to the array in your FormBuilder:

'attr'=> array('class'=>'span2')

String concatenation: concat() vs "+" operator

I don't think so.

a.concat(b) is implemented in String and I think the implementation didn't change much since early java machines. The + operation implementation depends on Java version and compiler. Currently + is implemented using StringBuffer to make the operation as fast as possible. Maybe in the future, this will change. In earlier versions of java + operation on Strings was much slower as it produced intermediate results.

I guess that += is implemented using + and similarly optimized.

LINQ: Distinct values

In addition to Jon Skeet's answer, you can also use the group by expressions to get the unique groups along w/ a count for each groups iterations:

var query = from e in doc.Elements("whatever")
            group e by new { id = e.Key, val = e.Value } into g
            select new { id =, val = g.Key.val, count = g.Count() };

CSS selector (id contains part of text)

Try this:


This will get you all a elements with id containing


and have the id ending in


How to configure Chrome's Java plugin so it uses an existing JDK in the machine

On Ubuntu, You can follow these steps to resolve the issue:

  1. Create a directory named plugins inside $HOME/.mozilla, if it doesn't exist already
  2. Create a symlink to inside this directory using this command:

    ln -s $JAVA_HOME/jre/lib/i386/ $MOZILLA_HOME/plugins


    ln -s $JAVA_HOME/jre/lib/amd64/ $MOZILLA_HOME/plugins

    depending on whether you're using a 32 or 64 bit JVM installation. Moreover, $JAVA_HOME is the location of your JVM installation.

More detailed instructions can be found here.

Make column fixed position in bootstrap

Updated for Bootstrap 4

Bootstrap 4 now includes a position-fixed class for this purpose so there is no need for additional CSS...

<div class="container">
    <div class="row">
        <div class="col-lg-3">
            <div class="position-fixed">
                Fixed content
        <div class="col-lg-9">
            Normal scrollable content

iOS 9 not opening Instagram app with URL SCHEME

iOS 9 has made a small change to the handling of URL scheme. You must whitelist the url's that your app will call out to using the LSApplicationQueriesSchemes key in your Info.plist.

Please see post here:

The main conclusion is that:

If you call the “canOpenURL” method on a URL that is not in your whitelist, it will return “NO”, even if there is an app installed that has registered to handle this scheme. A “This app is not allowed to query for scheme xxx” syslog entry will appear.

If you call the “openURL” method on a URL that is not in your whitelist, it will fail silently. A “This app is not allowed to query for scheme xxx” syslog entry will appear.

The author also speculates that this is a bug with the OS and Apple will fix this in a subsequent release.

Is it possible to log all HTTP request headers with Apache?

mod_log_forensic is what you want, but it may not be included/available with your Apache install by default.

Here is how to use it.

LoadModule log_forensic_module /usr/lib64/httpd/modules/ 
<IfModule log_forensic_module> 
ForensicLog /var/log/httpd/forensic_log 

What is a "thread" (really)?

I am going to use a lot of text from the book Operating Systems Concepts by ABRAHAM SILBERSCHATZ, PETER BAER GALVIN and GREG GAGNE along with my own understanding of things.


Any application resides in the computer in the form of text (or code).

We emphasize that a program by itself is not a process. A program is a passive entity, such as a file containing a list of instructions stored on disk (often called an executable file).

When we start an application, we create an instance of execution. This instance of execution is called a process. EDIT:(As per my interpretation, analogous to a class and an instance of a class, the instance of a class being a process. )

An example of processes is that of Google Chrome. When we start Google Chrome, 3 processes are spawned:

• The browser process is responsible for managing the user interface as well as disk and network I/O. A new browser process is created when Chrome is started. Only one browser process is created.

Renderer processes contain logic for rendering web pages. Thus, they contain the logic for handling HTML, Javascript, images, and so forth. As a general rule, a new renderer process is created for each website opened in a new tab, and so several renderer processes may be active at the same time.

• A plug-in process is created for each type of plug-in (such as Flash or QuickTime) in use. Plug-in processes contain the code for the plug-in as well as additional code that enables the plug-in to communicate with associated renderer processes and the browser process.


To answer this I think you should first know what a processor is. A Processor is the piece of hardware that actually performs the computations. EDIT: (Computations like adding two numbers, sorting an array, basically executing the code that has been written)

Now moving on to the definition of a thread.

A thread is a basic unit of CPU utilization; it comprises a thread ID, a program counter, a register set, and a stack.

EDIT: Definition of a thread from intel's website:

A Thread, or thread of execution, is a software term for the basic ordered sequence of instructions that can be passed through or processed by a single CPU core.

So, if the Renderer process from the Chrome application sorts an array of numbers, the sorting will take place on a thread/thread of execution. (The grammar regarding threads seems confusing to me)

My Interpretation of Things

A process is an execution instance. Threads are the actual workers that perform the computations via CPU access. When there are multiple threads running for a process, the process provides common memory.

EDIT: Other Information that I found useful to give more context

All modern day computer have more than one threads. The number of threads in a computer depends on the number of cores in a computer.

Concurrent Computing:

From Wikipedia:

Concurrent computing is a form of computing in which several computations are executed during overlapping time periods—concurrently—instead of sequentially (one completing before the next starts). This is a property of a system—this may be an individual program, a computer, or a network—and there is a separate execution point or "thread of control" for each computation ("process").

So, I could write a program which calculates the sum of 4 numbers:

(1 + 3) + (4 + 5)

In the program to compute this sum (which will be one process running on a thread of execution) I can fork another process which can run on a different thread to compute (4 + 5) and return the result to the original process, while the original process calculates the sum of (1 + 3).

Adding Table rows Dynamically in Android

Create an init() function and point the table layout. Then create the needed rows and columns.

   public void init() {
            TableLayout stk = (TableLayout) findViewById(;
            TableRow tbrow0 = new TableRow(this);
            TextView tv0 = new TextView(this);
            tv0.setText(" Sl.No ");
            TextView tv1 = new TextView(this);
            tv1.setText(" Product ");
            TextView tv2 = new TextView(this);
            tv2.setText(" Unit Price ");
            TextView tv3 = new TextView(this);
            tv3.setText(" Stock Remaining ");
            for (int i = 0; i < 25; i++) {
                TableRow tbrow = new TableRow(this);
                TextView t1v = new TextView(this);
                t1v.setText("" + i);
                TextView t2v = new TextView(this);
                t2v.setText("Product " + i);
                TextView t3v = new TextView(this);
                t3v.setText("Rs." + i);
                TextView t4v = new TextView(this);
                t4v.setText("" + i * 15 / 32 * 10);


Call init function in your onCreate method:

    protected void onCreate(Bundle savedInstanceState) {


Layout file like:

        android:layout_alignParentLeft="true" >

            android:layout_height="wrap_content" >

                android:orientation="vertical" >

                    android:layout_centerHorizontal="true" >

Will look like:

enter image description here

Android BroadcastReceiver within Activity

What do I do wrong?

The source code of ToastDisplay is OK (mine is similar and works), but it will only receive something, if it is currently in foreground (you register receiver in onResume). But it can not receive anything if a different activity (in this case SendBroadcast activity) is shown.

Instead you probably want to startActivity ToastDisplay from the first activity?

BroadcastReceiver and Activity make sense in a different use case. In my application I need to receive notifications from a background GPS tracking service and show them in the activity (if the activity is in the foreground).

There is no need to register the receiver in the manifest. It would be even harmful in my use case - my receiver manipulates the UI of the activity and the UI would not be available during onReceive if the activity is not currently shown. Instead I register and unregister the receiver for activity in onResume and onPause as described in BroadcastReceiver documentation:

You can either dynamically register an instance of this class with Context.registerReceiver() or statically publish an implementation through the tag in your AndroidManifest.xml.

How do I put a variable inside a string?

I had a need for an extended version of this: instead of embedding a single number in a string, I needed to generate a series of file names of the form 'file1.pdf', 'file2.pdf' etc. This is how it worked:

['file' + str(i) + '.pdf' for i in range(1,4)]

React Js: Uncaught (in promise) SyntaxError: Unexpected token < in JSON at position 0

This error can be received but be aware it can be a red herring to the real issue. In my case, there wasn't an issue with the JSON as the error states, but rather a 404 was occurring that it could not pull the JSON data to process in the 1st place thus resulting in this error.

The fix for this was that in order to use fetch on a .json file in a local project, the .json file must be accessible. This can be done by placing it in a folder such as the public folder in the root of the project. Once I moved the json file into that folder, the 404 turned into a 200, and the Unexpected token < in JSON at position 0 error was resolved.

JavaScript: Class.method vs. Class.prototype.method

When you create more than one instance of MyClass , you will still only have only one instance of publicMethod in memory but in case of privilegedMethod you will end up creating lots of instances and staticMethod has no relationship with an object instance.

That's why prototypes save memory.

Also, if you change the parent object's properties, is the child's corresponding property hasn't been changed, it'll be updated.

Compare two columns using pandas

Use if you have multiple conditions to be checked from the dataframe and output a specific choice in a different column


df["new column"],choice,default=)

Note: No of conditions and no of choices should match, repeat text in choice if for two different conditions you have same choices

keytool error bash: keytool: command not found

In Windows 10, you need to add a double slash

./keytool -genkey -v -keystore c:\\Users\\USERNAME\\youralias.jks -storetype JKS -keyalg RSA -keysize 2048 -validity 10000 -alias youralias

How do you get the index of the current iteration of a foreach loop?

If the collection is a list, you can use List.IndexOf, as in:

foreach (Object o in collection)
    // ...

Html.Textbox VS Html.TextboxFor

Html.TextBox amd Html.DropDownList are not strongly typed and hence they doesn't require a strongly typed view. This means that we can hardcode whatever name we want. On the other hand, Html.TextBoxFor and Html.DropDownListFor are strongly typed and requires a strongly typed view, and the name is inferred from the lambda expression.

Strongly typed HTML helpers also provide compile time checking.

Since, in real time, we mostly use strongly typed views, prefer to use Html.TextBoxFor and Html.DropDownListFor over their counterparts.

Whether, we use Html.TextBox & Html.DropDownList OR Html.TextBoxFor & Html.DropDownListFor, the end result is the same, that is they produce the same HTML.

Strongly typed HTML helpers are added in MVC2.

Parse json string to find and element (key / value)

Use a JSON parser, like JSON.NET

string json = "{ \"Atlantic/Canary\": \"GMT Standard Time\", \"Europe/Lisbon\": \"GMT Standard Time\", \"Antarctica/Mawson\": \"West Asia Standard Time\", \"Etc/GMT+3\": \"SA Eastern Standard Time\", \"Etc/GMT+2\": \"UTC-02\", \"Etc/GMT+1\": \"Cape Verde Standard Time\", \"Etc/GMT+7\": \"US Mountain Standard Time\", \"Etc/GMT+6\": \"Central America Standard Time\", \"Etc/GMT+5\": \"SA Pacific Standard Time\", \"Etc/GMT+4\": \"SA Western Standard Time\", \"Pacific/Wallis\": \"UTC+12\", \"Europe/Skopje\": \"Central European Standard Time\", \"America/Coral_Harbour\": \"SA Pacific Standard Time\", \"Asia/Dhaka\": \"Bangladesh Standard Time\", \"America/St_Lucia\": \"SA Western Standard Time\", \"Asia/Kashgar\": \"China Standard Time\", \"America/Phoenix\": \"US Mountain Standard Time\", \"Asia/Kuwait\": \"Arab Standard Time\" }";
var data = (JObject)JsonConvert.DeserializeObject(json);
string timeZone = data["Atlantic/Canary"].Value<string>();

How can I map True/False to 1/0 in a Pandas DataFrame?

This question specifically mentions a single column, so the currently accepted answer works. However, it doesn't generalize to multiple columns. For those interested in a general solution, use the following:

df.replace({False: 0, True: 1}, inplace=True)

This works for a DataFrame that contains columns of many different types, regardless of how many are boolean.

How to retrieve data from sqlite database in android and display it in TextView

You are using getData() method as void.

You can not return values from void.

Adding new line of data to TextBox

If you use WinForms:

Use the AppendText(myTxt) method on the TextBox instead (.net 3.5+):

    private void button1_Click(object sender, EventArgs e)
        string sent = chatBox.Text;



Text in itself has typically a low memory footprint (you can say a lot within f.ex. 10kb which is "nothing"). The TextBox does not render all text that is in the buffer, only the visible part so you don't need to worry too much about lag. The slower operations are inserting text. Appending text is relatively fast.

If you need a more complex handling of the content you can use StringBuilder combined with the textbox. This will give you a very efficient way of handling text.

IF... OR IF... in a windows batch file

Realizing this is a bit of an old question, the responses helped me come up with a solution to testing command line arguments to a batch file; so I wanted to post my solution as well in case anyone else was looking for a similar solution.

First thing that I should point out is that I was having trouble getting IF ... ELSE statements to work inside of a FOR ... DO clause. Turns out (thanks to dbenham for inadvertently pointing this out in his examples) the ELSE statement cannot be on a separate line from the closing parens.

So instead of this:

FOR ... DO (
    IF ... (
    ELSE (

Which is my preference for readability and aesthetic reasons, you have to do this:

FOR ... DO (
    IF ... (
    ) ELSE (

Now the ELSE statement doesn't return as an unrecognized command.

Finally, here's what I was attempting to do - I wanted to be able to pass several arguments to a batch file in any order, ignoring case, and reporting/failing on undefined arguments passed in. So here's my solution...

SET ARGS=(arg1 Arg1 ARG1 arg2 Arg2 ARG2 arg3 Arg3 ARG3)

FOR %%A IN (%*) DO (
    FOR %%B in %ARGS% DO (
        IF [%%A] == [%%B] SET TRUE=1
        SET %%A=TRUE
        ) ELSE (
        SET ARG=%%A


ECHO "%ARG%" is not an acceptable argument.


Note, this will only report on the first failed argument. So if the user passes in more than one unacceptable argument, they will only be told about the first until it's corrected, then the second, etc.

Remove rows not .isin('X')

You can use the method:

In [1]: df = pd.DataFrame([[1,2],[3,4]], index=['A','B'])

In [2]: df
   0  1
A  1  2
B  3  4

In [3]: L = ['A']

In [4]: x: x in L)
   0  1
A  1  2

seek() function?

The seek function expect's an offset in bytes.

Ascii File Example:

So if you have a text file with the following content:



You can jump 1 byte to skip over the first character as following:

fp = open('simple.txt', 'r')
print fp.readline()
>>> bc

Binary file example gathering width :

fp = open('afile.png', 'rb')
print 'width: {0}'.format(struct.unpack('>i',[0])
print 'height: ', struct.unpack('>i',[0]

Note: Once you call read you are changing the position of the read-head, which act's like seek.

what is the difference between GROUP BY and ORDER BY in sql

  1. GROUP BY will aggregate records by the specified column which allows you to perform aggregation functions on non-grouped columns (such as SUM, COUNT, AVG, etc.). ORDER BY alters the order in which items are returned.
  2. If you do SELECT IsActive, COUNT(*) FROM Customers GROUP BY IsActive you get a count of active and inactive customers. The group by aggregated the results based on the field you specified. If you do SELECT * FROM Customers ORDER BY Name then you get the result list sorted by the customer’s name.
  3. If you GROUP, the results are not necessarily sorted; although in many cases they may come out in an intuitive order, that's not guaranteed by the GROUP clause. If you want your groups sorted, always use an explicitly ORDER BY after the GROUP BY.
  4. Grouped data cannot be filtered by WHERE clause. Order data can be filtered by WHERE clause.

How to disable editing of elements in combobox for c#?

Yow can change the DropDownStyle in properties to DropDownList. This will not show the TextBox for filter.

DropDownStyle Property
(Screenshot provided by FUSION CHA0S.)

add image to uitableview cell

All good answers from others. Here are two ways you can solve this:

  1. Directly from the code where you will have to programmatically control the dimensions of the imageview

    override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCell(withIdentifier: "xyz", for: indexPath)
        cell.imageView!.image = UIImage(named: "xyz") // if retrieving the image from the assets folder 
        return cell
  2. From the story board, where you can use the attribute inspector & size inspector in the utility pane to adjust positioning, add constraints and specify dimensions

    • In the storyboard, add an imageView object in to the cell's content view with your desired dimensions and add a tag to the view(imageView) in the attribute inspector. Then do the following in your viewController

      override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
          let cell = tableView.dequeueReusableCell(withIdentifier: "xyz", for: indexPath)
          let pictureView = cell.viewWithTag(119) as! UIImageView //let's assume the tag is set to 119
          pictureView.image = UIImage(named: "xyz") // if retrieving the image from the assets folder 
          return cell

Apply multiple functions to multiple groupby columns

Pandas >= 0.25.0, named aggregations

Since pandas version 0.25.0 or higher, we are moving away from the dictionary based aggregation and renaming, and moving towards named aggregations which accepts a tuple. Now we can simultaneously aggregate + rename to a more informative column name:


df = pd.DataFrame(np.random.rand(4,4), columns=list('abcd'))
df['group'] = [0, 0, 1, 1]

          a         b         c         d  group
0  0.521279  0.914988  0.054057  0.125668      0
1  0.426058  0.828890  0.784093  0.446211      0
2  0.363136  0.843751  0.184967  0.467351      1
3  0.241012  0.470053  0.358018  0.525032      1

Apply GroupBy.agg with named aggregation:

             a_sum=('a', 'sum'),
             a_mean=('a', 'mean'),
             b_mean=('b', 'mean'),
             c_sum=('c', 'sum'),
             d_range=('d', lambda x: x.max() - x.min())

          a_sum    a_mean    b_mean     c_sum   d_range
0      0.947337  0.473668  0.871939  0.838150  0.320543
1      0.604149  0.302074  0.656902  0.542985  0.057681

How to create permanent PowerShell Aliases

UPDATED - January 2021

It's possible to store in a profile.ps1 file any PowerShell code to be executed each time PowerShell starts. There are at least 6 different paths where to store the code depending on which user has to execute it. We will consider only 2 of them: the "all users" and the "only your user" paths (follow the previous link for further options).

To answer your question, you only have to create a profile.ps1 file containing the code you want to be executed, that is:

New-Alias Goto Set-Location

and save it in the proper path:

  • "$Home\Documents" (usually C:\Users<yourname>\Documents): Only your user will execute the code. This is the reccomanded place.
    You can quickly find your profile location by running echo $profile in PowerShell
  • $PsHome (C:\Windows\System32\WindowsPowerShell\v1.0): Every user will execute the code.

IMPORTANT: Remember you need to restart your PowerShell instances to apply the changes.


  • If both paths contain a profile.ps1 file, the all-users one is executed first, then the user-specific one. This means the user-specific commands will overwrite variables in case of duplicates or conflicts.

  • Always put the code in the user-specific profile if there is no need to extend its execution to every user. This is safer because you don't pollute other users' space (usually, you don't want to do that).
    Another advantage is that you don't need administrator rights to add the file to your user-space (you do for anything in C:\Windows\System32).

  • If you really need to execute the profile code for every user, mind that the $PsHome path is different for 32bit and 64bit instances of PowerShell. You should consider both environments if you want to always execute the profile code.
    The paths are:

    • C:\Windows\System32\WindowsPowerShell\v1.0 for the 64bit environment
    • C:\Windows\SysWow64\WindowsPowerShell\v1.0 for the 32bit one (Yeah I know, the folder naming is counterintuitive, but it's correct).

How to read text file in JavaScript

(fiddle: )

  1. Usage


<textarea id='tbMain' ></textarea>
<a id='btnOpen' href='#' >Open</a>


document.getElementById('btnOpen').onclick = function(){
        document.getElementById('tbMain').value = txt; 
  1. Js Helper functions
function openFile(callBack){
  var element = document.createElement('input');
  element.setAttribute('type', "file");
  element.setAttribute('id', "btnOpenFile");
  element.onchange = function(){
      } = 'none';

function readText(filePath,callBack) {
    var reader;
    if (window.File && window.FileReader && window.FileList && window.Blob) {
        reader = new FileReader();
    } else {
        alert('The File APIs are not fully supported by your browser. Fallback required.');
        return false;
    var output = ""; //placeholder for text output
    if(filePath.files && filePath.files[0]) {           
        reader.onload = function (e) {
            output =;
        };//end onload()
    }//end if html5 filelist support
    else { //this is where you could fallback to Java Applet, Flash or similar
        return false;
    return true;

How to delete the last row of data of a pandas dataframe

Surprised nobody brought this one up:

# To remove last n rows

# To remove first n rows

Running a speed test on a DataFrame of 1000 rows shows that slicing and head/tail are ~6 times faster than using drop:

>>> %timeit df[:-1]
125 µs ± 132 ns per loop (mean ± std. dev. of 7 runs, 10000 loops each)

>>> %timeit df.head(-1)
129 µs ± 1.18 µs per loop (mean ± std. dev. of 7 runs, 10000 loops each)

>>> %timeit df.drop(df.tail(1).index)
751 µs ± 20.4 µs per loop (mean ± std. dev. of 7 runs, 1000 loops each)

Javascript Cookie with no expiration date

YOU JUST CAN'T. There's no exact code to use for setting a forever cookie but an old trick will do, like current time + 10 years.

Just a note that any dates beyond January 2038 will doomed you for the cookies (32-bit int) will be deleted instantly. Wish for a miracle that that will be fixed in the near future. For 64-bit int, years around 2110 will be safe. As time goes by, software and hardware will change and may never adapt to older ones (the things we have now) so prepare the now for the future.

See Year 2038 problem

Linux cmd to search for a class file among jars irrespective of jar path

I have used this small snippet. Might be slower but works every time.

for i in 'find . -type f -name "*.jar"'; do
    jar tvf $i | grep "";
    if [ $? -eq 0 ]; then echo $i; fi;

Can we update primary key values of a table?

You can as long as

  • The value is unique
  • No existing foreign keys are violated

How to scroll to bottom in react?

import React, {Component} from 'react';

export default class ChatOutPut extends Component {

    constructor(props) {
        this.state = {
            messages: props.chatmessages
    componentDidUpdate = (previousProps, previousState) => {
        if (this.refs.chatoutput != null) {
            this.refs.chatoutput.scrollTop = this.refs.chatoutput.scrollHeight;
    renderMessage(data) {
        return (
            <div key={data.key}>
    render() {
        return (
            <div ref='chatoutput' className={classes.chatoutputcontainer}>
                {, this)}


Pax is correct about the reasons for TIME_WAIT, and why you should be careful about lowering the default setting.

A better solution is to vary the port numbers used for the originating end of your sockets. Once you do this, you won't really care about time wait for individual sockets.

For listening sockets, you can use SO_REUSEADDR to allow the listening socket to bind despite the TIME_WAIT sockets sitting around.

Vertically aligning a checkbox

Vertical alignment only works on inline elements. If you float it, then I don't think it is treated as part of that stream of inline elements any more.

Make the label an inline-block, and use vertical alignment on both the label and the input to align their middles. Then, assuming it is okay to have a specific width on the labels and checkboxes, use relative positioning instead of floating to swap them (jsFiddle demo):

input {
    width: 20px;

    position: relative;
    left: 200px;

    vertical-align: middle;

label {  
    width: 200px;

    position: relative;
    left: -20px;

    display: inline-block;
    vertical-align: middle;

Kubernetes how to make Deployment to update image

I am using Azure DevOps to deploy the containerize applications, I am easily manage to overcome this problem by using the build ID

Everytime its builds and generate the new Build ID, I use this build ID as tag for docker image here is example


once your image is build (CI) successfully, in CD pipeline in deployment yml file I have give image name as


here evn:buildid is the azure devops variable which having value of build ID.

so now every time I have new changes to build(CI) and deploy(CD).

please comment if you need build definition for CI/CD.

Why are only a few video games written in Java?

  1. Java is slow, most of the heavy lifting is not handled by the GPU. There's still animation, physics, and AI hitting the CPU, all of which are very time-consuming.

  2. Java doesn't exist on consoles, and consoles are a major target for commercial games. If you use Java on PC, you're eliminating your ability to port to consoles within reasonable time and budget.

  3. Many of the more experienced coders in the game industry have been using C and C++ long before Java became popular. The two points above may contribute to this, but I expect that many professional game coders just don't really know Java all that well.

  4. Someone else's point about middleware above was a good one, so I'm adding it to my answer. There's a lot of legacy code and middleware written specifically to link with C/C++, and last I checked Java doesn't have good interoperability. Using Java for most companies would involve throwing out a lot of code, much of which has been paid for in one way or another.

Get specific ArrayList item


For future reference, you should refer to the Java API for these types of questions:

It's a useful thing!

Convert or extract TTC font to TTF - how to?

Assuming that Windows doesn't really know how to deal with TTC files (which I honestly find strange), you can "split" the combined fonts in an easy way if you use fontforge.

The steps are:

  1. Download the file.
  2. Unzip it (e.g., unzip "STHeiti").
  3. Load Fontforge.
  4. Open it with Fontforge (e.g., File > Open).
  5. Fontforge will tell you that there are two fonts "packed" in this particular TTC file (at least as of 2014-01-29) and ask you to choose one.
  6. After the font is loaded (it may take a while, as this font is very large), you can ask Fontforge to generate the TTF file via the menu File > Generate Fonts....

Repeat the steps of loading 4--6 for the other font and you will have your TTFs readily usable for you.

Note that I emphasized generating instead of saving above: saving the font will create a file in Fontforge's specific SFD format, which is probably useless to you, unless you want to develop fonts with Fontforge.

If you want to have a more programmatic/automatic way of manipulating fonts, then you might be interested in my answer to a similar (but not exactly the same) question.


Further comments: One reason why some people may be interested in performing the splitting mentioned above (or using a font converter after all) is to convert the fonts to web formats (like WOFF). That's great, but be careful to see if the license of the fonts that you are splitting/converting allows such wide redistribution.

Of course, for Free ("as in Freedom") fonts, you don't need to worry (and one of the most prominent licenses of such fonts is the OFL).

How do I merge two dictionaries in a single expression (taking union of dictionaries)?

It's so silly that .update returns nothing.
I just use a simple helper function to solve the problem:

def merge(dict1,*dicts):
    for dict2 in dicts:
    return dict1


merge({},dict1,dict2)  # this one returns a new copy

Group by in LINQ


persons.GroupBy(x => x.PersonId).Select(x => x)


to check if any person is repeating in your list try

persons.GroupBy(x => x.PersonId).Where(x => x.Count() > 1).Any(x => x)

SQL Server Output Clause into a scalar variable

Way later but still worth mentioning is that you can also use variables to output values in the SET clause of an UPDATE or in the fields of a SELECT;

DECLARE @val1 int;
DECLARE @val2 int;
UPDATE [dbo].[PortalCounters_TEST]
SET @val1 = NextNum, @val2 = NextNum = NextNum + 1
WHERE [Condition] = 'unique value'
SELECT @val1, @val2

In the example above @val1 has the before value and @val2 has the after value although I suspect any changes from a trigger would not be in val2 so you'd have to go with the output table in that case. For anything but the simplest case, I think the output table will be more readable in your code as well.

One place this is very helpful is if you want to turn a column into a comma-separated list;

DECLARE @list varchar(max) = '';
DECLARE @comma varchar(2) = '';
SELECT @list = @list + @comma + County, @comma = ', ' FROM County
print @list

Executors.newCachedThreadPool() versus Executors.newFixedThreadPool()

You must use newCachedThreadPool only when you have short-lived asynchronous tasks as stated in Javadoc, if you submit tasks which takes longer time to process, you will end up creating too many threads. You may hit 100% CPU if you submit long running tasks at faster rate to newCachedThreadPool (

Increasing nesting function calls limit

This error message comes specifically from the XDebug extension. PHP itself does not have a function nesting limit. Change the setting in your php.ini:

xdebug.max_nesting_level = 200

or in your PHP code:

ini_set('xdebug.max_nesting_level', 200);

As for if you really need to change it (i.e.: if there's a alternative solution to a recursive function), I can't tell without the code.

Can I use a :before or :after pseudo-element on an input field?

If you are trying to style an input element with :before and :after, odds are you are trying to mimic the effects of other span, div, or even a elements in your CSS stack.

As Robert Koritnik's answer points out, :before and :after can only be applied to container elements and input elements are not containers.

HOWEVER, HTML 5 introduced the button element which is a container and behaves like an input[type="submit|reset"] element.

    .happy:after { content:url(smiley.gif); }

    <!-- won't work -->
    <input class="happy" type="submit" value="Submit" />

    <!-- works -->
    <button class="happy">Submit</button>

EditText non editable

android:editable="false" should work, but it is deprecated, you should be using android:inputType="none" instead.

Alternatively, if you want to do it in the code you could do this :

EditText mEdit = (EditText) findViewById(;

This is also a viable alternative :

EditText mEdit = (EditText) findViewById(;

If you're going to make your EditText non-editable, may I suggest using the TextView widget instead of the EditText, since using a EditText seems kind of pointless in that case.

EDIT: Altered some information since I've found that android:editable is deprecated, and you should use android:inputType="none", but there is a bug about it on android code; So please check this.

Java converting Image to BufferedImage

If you use Kotlin, you can add an extension method to Image in the same manner Sri Harsha Chilakapati suggests.

fun Image.toBufferedImage(): BufferedImage {
    if (this is BufferedImage) {
        return this
    val bufferedImage = BufferedImage(this.getWidth(null), this.getHeight(null), BufferedImage.TYPE_INT_ARGB)

    val graphics2D = bufferedImage.createGraphics()
    graphics2D.drawImage(this, 0, 0, null)

    return bufferedImage

And use it like this:


How to implement the ReLU function in Numpy

If we have 3 parameters (t0, a0, a1) for Relu, that is we want to implement

if x > t0:
    x = x * a1
    x = x * a0

We can use the following code:

X = X * (X > t0) * a1 +  X * (X < t0) * a0

X there is a matrix.

Java - Using Accessor and Mutator methods

You need to remove the static from your accessor methods - these methods need to be instance methods and access the instance variables

public class IDCard {
    public String name, fileName;
    public int id;

    public IDCard(final String name, final String fileName, final int id) { = name;
        this.fileName = fileName = id;

    public String getName() {
        return name;

You can the create an IDCard and use the accessor like this:

final IDCard card = new IDCard();

Each time you call new a new instance of the IDCard will be created and it will have it's own copies of the 3 variables.

If you use the static keyword then those variables are common across every instance of IDCard.

A couple of things to bear in mind:

  1. don't add useless comments - they add code clutter and nothing else.
  2. conform to naming conventions, use lower case of variable names - name not Name.

Python add item to the tuple

Bottom line, the easiest way to append to a tuple is to enclose the element being added with parentheses and a comma.

t = ('a', 4, 'string')
t = t + (5.0,)

out: ('a', 4, 'string', 5.0)

How to draw a filled circle in Java?

public void paintComponent(Graphics g) {
   Graphics2D g2d = (Graphics2D)g;
   // Assume x, y, and diameter are instance variables.
   Ellipse2D.Double circle = new Ellipse2D.Double(x, y, diameter, diameter);

Here are some docs about paintComponent (link).

You should override that method in your JPanel and do something similar to the code snippet above.

In your ActionListener you should specify x, y, diameter and call repaint().

Fixed header table with horizontal scrollbar and vertical scrollbar on

Here's a solution which again is not a CSS only solution. It is similar to avrahamcool's solution in that it uses a few lines of jQuery, but instead of changing heights and moving the header along, all it does is changing the width of tbody based on how far its parent table is scrolled along to the right.

An added bonus with this solution is that it works with a semantically valid HTML table.

It works great on all recent browser versions (IE10, Chrome, FF) and that's it, the scrolling functionality breaks on older versions.

But then the fact that you are using a semantically valid HTML table will save the day and ensure the table is still displayed properly, it's only the scrolling functionality that won't work on older browsers.

Here's a jsFiddle for demonstration purposes.


table {
    width: 300px;
    overflow-x: scroll;
    display: block;
thead, tbody {
    display: block;
tbody {
    overflow-y: scroll;
    overflow-x: hidden;
    height: 140px;
td, th {
    min-width: 100px;


$("table").on("scroll", function () {
    $("table > *").width($("table").width() + $("table").scrollLeft());

I needed a version which degrades nicely in IE9 (no scrolling, just a normal table). Posting the fiddle here as it is an improved version. All you need to do is set a height on the tr.

Additional CSS to make this solution degrade nicely in IE9

tr {
    height: 25px; /* This could be any value, it just needs to be set. */ 

Here's a jsFiddle demonstrating the nicely degrading in IE9 version of this solution.

Edit: Updated fiddle links to link to a version of the fiddle which contains fixes for issues mentioned in the comments. Just adding a snippet with the latest and greatest version while I'm at it:

$('table').on('scroll', function() {_x000D_
  $("table > *").width($("table").width() + $("table").scrollLeft());_x000D_
html {_x000D_
  font-family: verdana;_x000D_
  font-size: 10pt;_x000D_
  line-height: 25px;_x000D_
table {_x000D_
  border-collapse: collapse;_x000D_
  width: 300px;_x000D_
  overflow-x: scroll;_x000D_
  display: block;_x000D_
thead {_x000D_
  background-color: #EFEFEF;_x000D_
tbody {_x000D_
  display: block;_x000D_
tbody {_x000D_
  overflow-y: scroll;_x000D_
  overflow-x: hidden;_x000D_
  height: 140px;_x000D_
th {_x000D_
  min-width: 100px;_x000D_
  height: 25px;_x000D_
  border: dashed 1px lightblue;_x000D_
  overflow: hidden;_x000D_
  text-overflow: ellipsis;_x000D_
  max-width: 100px;_x000D_
<script src=""></script>_x000D_
      <th>Column 1</th>_x000D_
      <th>Column 2</th>_x000D_
      <th>Column 3</th>_x000D_
      <th>Column 4</th>_x000D_
      <th>Column 5</th>_x000D_
      <td>Row 1</td>_x000D_
      <td>Row 1</td>_x000D_
      <td>Row 1</td>_x000D_
      <td>Row 1</td>_x000D_
      <td>Row 2</td>_x000D_
      <td>Row 2</td>_x000D_
      <td>Row 2</td>_x000D_
      <td>Row 2</td>_x000D_
      <td>Row 2</td>_x000D_
      <td>Row 3</td>_x000D_
      <td>Row 3</td>_x000D_
      <td>Row 3</td>_x000D_
      <td>Row 3</td>_x000D_
      <td>Row 3</td>_x000D_
      <td>Row 4</td>_x000D_
      <td>Row 4</td>_x000D_
      <td>Row 4</td>_x000D_
      <td>Row 4</td>_x000D_
      <td>Row 4</td>_x000D_
      <td>Row 5</td>_x000D_
      <td>Row 5</td>_x000D_
      <td>Row 5</td>_x000D_
      <td>Row 5</td>_x000D_
      <td>Row 5</td>_x000D_
      <td>Row 6</td>_x000D_
      <td>Row 6</td>_x000D_
      <td>Row 6</td>_x000D_
      <td>Row 6</td>_x000D_
      <td>Row 6</td>_x000D_
      <td>Row 7</td>_x000D_
      <td>Row 7</td>_x000D_
      <td>Row 7</td>_x000D_
      <td>Row 7</td>_x000D_
      <td>Row 7</td>_x000D_
      <td>Row 8</td>_x000D_
      <td>Row 8</td>_x000D_
      <td>Row 8</td>_x000D_
      <td>Row 8</td>_x000D_
      <td>Row 8</td>_x000D_
      <td>Row 9</td>_x000D_
      <td>Row 9</td>_x000D_
      <td>Row 9</td>_x000D_
      <td>Row 9</td>_x000D_
      <td>Row 9</td>_x000D_
      <td>Row 10</td>_x000D_
      <td>Row 10</td>_x000D_
      <td>Row 10</td>_x000D_
      <td>Row 10</td>_x000D_
      <td>Row 10</td>_x000D_

Safe navigation operator (?.) or (!.) and null property paths

Since TypeScript 3.7 was released you can use optional chaining now.

Property example:

let x = foo?.bar.baz();

This is equvalent to:

let x = (foo === null || foo === undefined) ?
    undefined :;

Moreover you can call:

Optional Call

function(otherFn: (par: string) => void) {
   otherFn?.("some value");

otherFn will be called only if otherFn won't be equal to null or undefined

Usage optional chaining in IF statement


if (someObj && someObj.someProperty) {
    // ...

can be replaced now with this

if (someObj?.someProperty) {
    // ...


installing urllib in Python3.6

The corrected code is

import urllib.request
fhand = urllib.request.urlopen('')
counts = dict()
for line in fhand: 
    words = line.decode().split() 
for word in words: 
    counts[word] = counts.get(word, 0) + 1 

running the code above produces

{'Who': 1, 'is': 1, 'already': 1, 'sick': 1, 'and': 1, 'pale': 1, 'with': 1, 'grief': 1}

Set cookie and get cookie with JavaScript

These are much much better references than w3schools (the most awful web reference ever made):

Examples derived from these references:

// sets the cookie cookie1
document.cookie = 'cookie1=test; expires=Sun, 1 Jan 2023 00:00:00 UTC; path=/'

// sets the cookie cookie2 (cookie1 is *not* overwritten)
document.cookie = 'cookie2=test; expires=Sun, 1 Jan 2023 00:00:00 UTC; path=/'

// remove cookie2
document.cookie = 'cookie2=; expires=Thu, 01 Jan 1970 00:00:00 UTC; path=/'

The Mozilla reference even has a nice cookie library you can use.

Java stack overflow error - how to increase the stack size in Eclipse?

When the argument -Xss doesn't do the job try deleting the temporary files from:


This did the trick for me.

Which encoding opens CSV files correctly with Excel on both Mac and Windows?

This works for me

  1. Open the file in BBEdit or TextWrangler*.
  2. Set the file as Unicode (UTF-16 Little-Endian) (Line Endings can be Unix or Windows). Save!
  3. In Excel: Data > Get External Data > Import Text File...

Now the key point, choose MacIntosh as File Origin (it should be the first choice).

This is using Excel 2011 (version 14.4.2)

*There's a little dropdown at the bottom of the window

Displaying Total in Footer of GridView and also Add Sum of columns(row vise) in last Column

protected void gvBill_RowDataBound(object sender, GridViewRowEventArgs e)

        if (e.Row.RowType == DataControlRowType.DataRow)

            Total += Convert.ToDecimal(DataBinder.Eval(e.Row.DataItem, "InvMstAmount"));
        else if (e.Row.RowType == DataControlRowType.Footer)

            e.Row.Cells[7].Text = String.Format("{0:0}", "<b>" + Total + "</b>");

enter image description here

php multidimensional array get values

This is the way to iterate on this array:

foreach($hotels as $row) {
       foreach($row['rooms'] as $k) {
             echo $k['boards']['board_id'];
             echo $k['boards']['price'];

You want to iterate on the hotels and the rooms (the ones with numeric indexes), because those seem to be the "collections" in this case. The other arrays only hold and group properties.

Prevent text selection after double click

A simple Javascript function that makes the content inside a page-element unselectable:

function makeUnselectable(elem) {
  if (typeof(elem) == 'string')
    elem = document.getElementById(elem);
  if (elem) {
    elem.onselectstart = function() { return false; }; = "none"; = "none";
    elem.unselectable = "on";

Is it possible to declare a public variable in vba and assign a default value?

Just to offer you a different angle -

I find it's not a good idea to maintain public variables between function calls. Any variables you need to use should be stored in Subs and Functions and passed as parameters. Once the code is done running, you shouldn't expect the VBA Project to maintain the values of any variables.

The reason for this is that there is just a huge slew of things that can inadvertently reset the VBA Project while using the workbook. When this happens, any public variables get reset to 0.

If you need a value to be stored outside of your subs and functions, I highly recommend using a hidden worksheet with named ranges for any information that needs to persist.

Error: package or namespace load failed for ggplot2 and for data.table

For me, i had to uninstall R from brew brew uninstall --force R and then head over to the R website and download and install it from there.

How to screenshot website in JavaScript client-side / how Google did it? (no need to access HDD)

I needed to snapshot a div on the page (for a webapp I wrote) that is protected by JWT's and makes very heavy use of Angular.

I had no luck with any of the above methods.

I ended up taking the outerHTML of the div I needed, cleaning it up a little (*) and then sending it to the server where I run wkhtmltopdf against it.

This is working very well for me.

(*) various input devices in my pages didn't render as checked or have their text values when viewed in the pdf... So I run a little bit of jQuery on the html before I send it up for rendering. ex: for text input items -- I copy their .val()'s into 'value' attributes, which then can be seen by wkhtmlpdf

Can I run javascript before the whole page is loaded?

Not only can you, but you have to make a special effort not to if you don't want to. :-)

When the browser encounters a classic script tag when parsing the HTML, it stops parsing and hands over to the JavaScript interpreter, which runs the script. The parser doesn't continue until the script execution is complete (because the script might do document.write calls to output markup that the parser should handle).

That's the default behavior, but you have a few options for delaying script execution:

  1. Use JavaScript modules. A type="module" script is deferred until the HTML has been fully parsed and the initial DOM created. This isn't the primary reason to use modules, but it's one of the reasons:

    <script type="module" src="./my-code.js"></script>
    <!-- Or -->
    <script type="module">
    // Your code here

    The code will be fetched (if it's separate) and parsed in parallel with the HTML parsing, but won't be run until the HTML parsing is done. (If your module code is inline rather than in its own file, it is also deferred until HTML parsing is complete.)

    This wasn't available when I first wrote this answer in 2010, but here in 2020, all major modern browsers support modules natively, and if you need to support older browsers, you can use bundlers like Webpack and Rollup.js.

  2. Use the defer attribute on a classic script tag:

    <script defer src="./my-code.js"></script>

    As with the module, the code in my-code.js will be fetched and parsed in parallel with the HTML parsing, but won't be run until the HTML parsing is done. But, defer doesn't work with inline script content, only with external files referenced via src.

  3. I don't think it's what you want, but you can use the async attribute to tell the browser to fetch the JavaScript code in parallel with the HTML parsing, but then run it as soon as possible, even if the HTML parsing isn't complete. You can put it on a type="module" tag, or use it instead of defer on a classic script tag.

  4. Put the script tag at the end of the document, just prior to the closing </body> tag:

    <!doctype html>
    <!-- ... -->
    <!-- The document's HTML goes here -->
    <script type="module" src="./my-code.js"></script><!-- Or inline script -->

    That way, even though the code is run as soon as its encountered, all of the elements defined by the HTML above it exist and are ready to be used.

    It used to be that this caused an additional delay on some browsers because they wouldn't start fetching the code until the script tag was encountered, but modern browsers scan ahead and start prefetching. Still, this is very much the third choice at this point, both modules and defer are better options.

The spec has a useful diagram showing a raw script tag, defer, async, type="module", and type="module" async and the timing of when the JavaScript code is fetched and run:

enter image description here

Here's an example of the default behavior, a raw script tag:

.found {_x000D_
    color: green;_x000D_
<p>Paragraph 1</p>_x000D_
    if (typeof NodeList !== "undefined" && !NodeList.prototype.forEach) {_x000D_
        NodeList.prototype.forEach = Array.prototype.forEach;_x000D_
    document.querySelectorAll("p").forEach(p => {_x000D_
<p>Paragraph 2</p>

(See my answer here for details around that NodeList code.)

When you run that, you see "Paragraph 1" in green but "Paragraph 2" is black, because the script ran synchronously with the HTML parsing, and so it only found the first paragraph, not the second.

In contrast, here's a type="module" script:

.found {_x000D_
    color: green;_x000D_
<p>Paragraph 1</p>_x000D_
<script type="module">_x000D_
    document.querySelectorAll("p").forEach(p => {_x000D_
<p>Paragraph 2</p>

Notice how they're both green now; the code didn't run until HTML parsing was complete. That would also be true with a defer script with external content (but not inline content).

(There was no need for the NodeList check there because any modern browser supporting modules already has forEach on NodeList.)

In this modern world, there's no real value to the DOMContentLoaded event of the "ready" feature that PrototypeJS, jQuery, ExtJS, Dojo, and most others provided back in the day (and still provide); just use modules or defer. Even back in the day, there wasn't much reason for using them (and they were often used incorrectly, holding up page presentation while the entire jQuery library was loaded because the script was in the head instead of after the document), something some developers at Google flagged up early on. This was also part of the reason for the YUI recommendation to put scripts at the end of the body, again back in the day.

Set div height equal to screen size

You need to give height for the parent element too! Check out this fiddle.


html, body {height: 100%;}

#content, .container-fluid, .span9
    border: 1px solid #000;

JavaScript (using jQuery) Way:


Extract data from XML Clob using SQL from Oracle Database


SELECT EXTRACTVALUE(xmltype(testclob), '/DCResponse/ContextData/Field[@key="Decision"]') 
FROM traptabclob;

Here is a sqlfiddle demo

Splitting dataframe into multiple dataframes

Groupby can helps you:

grouped = data.groupby(['name'])

Then you can work with each group like with a dataframe for each participant. And DataFrameGroupBy object methods such as (apply, transform, aggregate, head, first, last) return a DataFrame object.

Or you can make list from grouped and get all DataFrame's by index:

l_grouped = list(grouped)

l_grouped[0][1] - DataFrame for first group with first name.

Stop and Start a service via batch or cmd file?

Syntax always gets me.... so...

Here is explicitly how to add a line to a batch file that will kill a remote service (on another machine) if you are an admin on both machines, run the .bat as an administrator, and the machines are on the same domain. The machine name follows the UNC format \myserver

sc \\ip.ip.ip.ip stop p4_1

In this case... p4_1 was both the Service Name and the Display Name, when you view the Properties for the service in Service Manager. You must use the Service Name.

For your Service Ops junkies... be sure to append your reason code and comment! i.e. '4' which equals 'Planned' and comment 'Stopping server for maintenance'

sc \\ip.ip.ip.ip stop p4_1 4 Stopping server for maintenance

React - How to force a function component to render?

This can be done without explicitly using hooks provided you add a prop to your component and a state to the stateless component's parent component:

const ParentComponent = props => {
  const [updateNow, setUpdateNow] = useState(true)

  const updateFunc = () => {

  const MyComponent = props => {
    return (<div> .... </div>)

  const MyButtonComponent = props => {
    return (<div> <input type="button" onClick={props.updateFunc} />.... </div>)

  return (
      <MyComponent updateMe={updateNow} />
      <MyButtonComponent updateFunc={updateFunc}/>

Two statements next to curly brace in an equation

That can be achieve in plain LaTeX without any specific package.

This is your only binary choices

This code produces something which looks what you seems to need.

curly braces in front of two lines

The same example as in the @Tombart can be obtained with similar code.



      1, & \mbox{if $x<0$}.\\
      0, & \mbox{otherwise}.


This code produces very similar results.

enter image description here

n-grams in python, four, five, six grams?

here is another simple way for do n-grams

>>> from nltk.util import ngrams
>>> text = "I am aware that nltk only offers bigrams and trigrams, but is there a way to split my text in four-grams, five-grams or even hundred-grams"
>>> tokenize = nltk.word_tokenize(text)
>>> tokenize
['I', 'am', 'aware', 'that', 'nltk', 'only', 'offers', 'bigrams', 'and', 'trigrams', ',', 'but', 'is', 'there', 'a', 'way', 'to', 'split', 'my', 'text', 'in', 'four-grams', ',', 'five-grams', 'or', 'even', 'hundred-grams']
>>> bigrams = ngrams(tokenize,2)
>>> bigrams
[('I', 'am'), ('am', 'aware'), ('aware', 'that'), ('that', 'nltk'), ('nltk', 'only'), ('only', 'offers'), ('offers', 'bigrams'), ('bigrams', 'and'), ('and', 'trigrams'), ('trigrams', ','), (',', 'but'), ('but', 'is'), ('is', 'there'), ('there', 'a'), ('a', 'way'), ('way', 'to'), ('to', 'split'), ('split', 'my'), ('my', 'text'), ('text', 'in'), ('in', 'four-grams'), ('four-grams', ','), (',', 'five-grams'), ('five-grams', 'or'), ('or', 'even'), ('even', 'hundred-grams')]
>>> trigrams=ngrams(tokenize,3)
>>> trigrams
[('I', 'am', 'aware'), ('am', 'aware', 'that'), ('aware', 'that', 'nltk'), ('that', 'nltk', 'only'), ('nltk', 'only', 'offers'), ('only', 'offers', 'bigrams'), ('offers', 'bigrams', 'and'), ('bigrams', 'and', 'trigrams'), ('and', 'trigrams', ','), ('trigrams', ',', 'but'), (',', 'but', 'is'), ('but', 'is', 'there'), ('is', 'there', 'a'), ('there', 'a', 'way'), ('a', 'way', 'to'), ('way', 'to', 'split'), ('to', 'split', 'my'), ('split', 'my', 'text'), ('my', 'text', 'in'), ('text', 'in', 'four-grams'), ('in', 'four-grams', ','), ('four-grams', ',', 'five-grams'), (',', 'five-grams', 'or'), ('five-grams', 'or', 'even'), ('or', 'even', 'hundred-grams')]
>>> fourgrams=ngrams(tokenize,4)
>>> fourgrams
[('I', 'am', 'aware', 'that'), ('am', 'aware', 'that', 'nltk'), ('aware', 'that', 'nltk', 'only'), ('that', 'nltk', 'only', 'offers'), ('nltk', 'only', 'offers', 'bigrams'), ('only', 'offers', 'bigrams', 'and'), ('offers', 'bigrams', 'and', 'trigrams'), ('bigrams', 'and', 'trigrams', ','), ('and', 'trigrams', ',', 'but'), ('trigrams', ',', 'but', 'is'), (',', 'but', 'is', 'there'), ('but', 'is', 'there', 'a'), ('is', 'there', 'a', 'way'), ('there', 'a', 'way', 'to'), ('a', 'way', 'to', 'split'), ('way', 'to', 'split', 'my'), ('to', 'split', 'my', 'text'), ('split', 'my', 'text', 'in'), ('my', 'text', 'in', 'four-grams'), ('text', 'in', 'four-grams', ','), ('in', 'four-grams', ',', 'five-grams'), ('four-grams', ',', 'five-grams', 'or'), (',', 'five-grams', 'or', 'even'), ('five-grams', 'or', 'even', 'hundred-grams')]

get current url in twig template?

{{ path(app.request.attributes.get('_route'),
     app.request.attributes.get('_route_params')) }}

If you want to read it into a view variable:

{% set currentPath = path(app.request.attributes.get('_route'),
                       app.request.attributes.get('_route_params')) %}

The app global view variable contains all sorts of useful shortcuts, such as app.session and, that reference the services you might use in a controller.

Convert string to date then format the date

Tested this code

java.text.DateFormat formatter = new java.text.SimpleDateFormat("MM-dd-yyyy");
java.util.Date newDate = new java.util.Date();
System.out.println(formatter.format(newDate ));,5.0/docs/api/java/text/SimpleDateFormat.html

Post request with Wget?

Wget currently only supports x-www-form-urlencoded data. --post-file is not for transmitting files as form attachments, it expects data with the form: key=value&otherkey=example.

--post-data and --post-file work the same way: the only difference is that --post-data allows you to specify the data in the command line, while --post-file allows you to specify the path of the file that contain the data to send.

Here's the documentation:

           Use POST as the method for all HTTP requests and send the specified data
           in the request body.  --post-data sends string as data, whereas
           --post-file sends the contents of file.  Other than that, they work in
           exactly the same way. In particular, they both expect content of the
           form "key1=value1&key2=value2", with percent-encoding for special
           characters; the only difference is that one expects its content as a
           command-line parameter and the other accepts its content from a file. In
           particular, --post-file is not for transmitting files as form
           attachments: those must appear as "key=value" data (with appropriate
           percent-coding) just like everything else. Wget does not currently
           support "multipart/form-data" for transmitting POST data; only
           "application/x-www-form-urlencoded". Only one of --post-data and
           --post-file should be specified.

Regarding your authentication token, it should either be provided in the header, in the path of the url, or in the data itself. This must be indicated somewhere in the documentation of the service you use. In a POST request, as in a GET request, you must specify the data using keys and values. This way the server will be able to receive multiple information with specific names. It's similar with variables.

Hence, you can't just send a magic token to the server, you also need to specify the name of the key. If the key is "token", then it should be token=YOUR_TOKEN.

wget --post-data 'user=foo&password=bar'

Also, you should consider using curl if you can because it is easier to send files using it. There are many examples on the Internet for that.

Converting a factor to numeric without losing information R (as.numeric() doesn't seem to work)

First, factor consists of indices and levels. This fact is very very important when you are struggling with factor.

For example,

> z <- factor(letters[c(3, 2, 3, 4)])

# human-friendly display, but internal structure is invisible
> z
[1] c b c d
Levels: b c d

# internal structure of factor
> unclass(z)
[1] 2 1 2 3
[1] "b" "c" "d"

here, z has 4 elements.
The index is 2, 1, 2, 3 in that order.
The level is associated with each index: 1 -> b, 2 -> c, 3 -> d.

Then, as.numeric converts simply the index part of factor into numeric.
as.character handles the index and levels, and generates character vector expressed by its level.

?as.numeric says that Factors are handled by the default method.

How to send email from MySQL 5.1

I would be very concerned about putting the load of sending e-mails on my database server (small though it may be). I might suggest one of these alternatives:

  1. Have application logic detect the need to send an e-mail and send it.
  2. Have a MySQL trigger populate a table that queues up the e-mails to be sent and have a process monitor that table and send the e-mails.

How to delete a row from GridView?

using System;
using System.Configuration;
using System.Data;
using System.Linq;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Xml.Linq;
using System.Data.SqlClient;

public partial class Default3 : System.Web.UI.Page
   DataTable dt = new DataTable();
    DataSet Gds = new DataSet();
   // DataColumn colm1 = new DataColumn();
   //DataColumn colm2 = new DataColumn();

    protected void Page_Load(object sender, EventArgs e)
        dt.Columns.Add("ExpId", typeof(int));
        dt.Columns.Add("FirstName", typeof(string));


    protected void BtnLoad_Click(object sender, EventArgs e)
        //   gvLoad is Grid View Id
        if (gvLoad.Rows.Count == 0)
            dt = tblGridRow();
        gvLoad.DataSource = Gds;

    protected DataTable tblLoad()
        return dt;
    protected DataRow tblRow()
        DataRow dr;
        dr = dt.NewRow();
        dr["Exp Id"] = Convert.ToInt16(txtId.Text);
        dr["First Name"] = Convert.ToString(txtName.Text);
        return dr;

    protected DataTable tblGridRow()
        DataRow dr;
        for (int i = 0; i < gvLoad.Rows.Count; i++)
            if (gvLoad.Rows[i].Cells[0].Text != null)

                dr = dt.NewRow();
                dr["Exp Id"] = gvLoad.Rows[i].Cells[1].Text.ToString();
                dr["First Name"] = gvLoad.Rows[i].Cells[2].Text.ToString();


        return dt;

    protected void btn_Click(object sender, EventArgs e)
        dt = tblGridRow();
        Session["tab"] = dt;
        // Response.Redirect("Default.aspx");

    protected void gvLoad_RowDeleting(object sender, GridViewDeleteEventArgs e)
        dt = tblGridRow();
        gvLoad.DataSource = dt;

What does "\r" do in the following script?

Actually, this has nothing to do with the usual Windows / Unix \r\n vs \n issue. The TELNET procotol itself defines \r\n as the end-of-line sequence, independently of the operating system. See RFC854.

Java regex to extract text between tags

You're on the right track. Now you just need to extract the desired group, as follows:

final Pattern pattern = Pattern.compile("<tag>(.+?)</tag>", Pattern.DOTALL);
final Matcher matcher = pattern.matcher("<tag>String I want to extract</tag>");
System.out.println(; // Prints String I want to extract

If you want to extract multiple hits, try this:

public static void main(String[] args) {
    final String str = "<tag>apple</tag><b>hello</b><tag>orange</tag><tag>pear</tag>";
    System.out.println(Arrays.toString(getTagValues(str).toArray())); // Prints [apple, orange, pear]

private static final Pattern TAG_REGEX = Pattern.compile("<tag>(.+?)</tag>", Pattern.DOTALL);

private static List<String> getTagValues(final String str) {
    final List<String> tagValues = new ArrayList<String>();
    final Matcher matcher = TAG_REGEX.matcher(str);
    while (matcher.find()) {
    return tagValues;

However, I agree that regular expressions are not the best answer here. I'd use XPath to find elements I'm interested in. See The Java XPath API for more info.

Resizing an iframe based on content

function frameSize(id){
var frameHeight;

document.getElementById(id).height=0 + "px";

document.getElementById(id).height= (frameHeight) + "px";


<iframe id="frame"  src="startframe.html" frameborder="0" marginheight="0" hspace=20     width="100%" 


<p>This will work, but you need to host it on an http server, you can do it locally.    </p>

Eclipse/Java code completion not working

Just in case anyone got to a desperate point where nothing works... It happened to us that the content assist somehow shrunk so no suggestion was shown, just the "Press Ctrl+Space for non-Java..." could be seen. So, it was just a matter of dragging the corner of the content assist to enlarge the pop-up.

I know, embarrassing. Hope it helps.

Note: this was an Ubuntu server with Xfce4 using Eclipse Oxygen.

Android Studio does not show layout preview

Change the Android version to use while rendering layouts in the IDE.

Go to your xml layout file -> Design -> change Android API version from Automatically Pick Best to a value in between your minimum and target sdk versions.

ORA-06550: line 1, column 7 (PL/SQL: Statement ignored) Error

If the value stored in PropertyLoader.RET_SECONDARY_V_ARRAY is not "V_ARRAY", then you are using different types; even if they are declared identically (e.g. both are table of number) this will not work.

You're hitting this data type compatibility restriction:

You can assign a collection to a collection variable only if they have the same data type. Having the same element type is not enough.

You're trying to call the procedure with a parameter that is a different type to the one it's expecting, which is what the error message is telling you.

Always pass weak reference of self into block in ARC?

Some explanation ignore a condition about the retain cycle [If a group of objects is connected by a circle of strong relationships, they keep each other alive even if there are no strong references from outside the group.] For more information, read the document

Build fat static library (device + simulator) using Xcode and SDK 4+

I have spent many hours trying to build a fat static library that will work on armv7, armv7s, and the simulator. Finally found a solution.

The gist is to build the two libraries (one for the device and then one for the simulator) separately, rename them to distinguish from each other, and then lipo -create them into one library.

lipo -create libPhone.a libSimulator.a -output libUniversal.a

I tried it and it works!

How to get current class name including package name in Java?

Use this.getClass().getCanonicalName() to get the full class name.

Note that a package / class name ("a.b.C") is different from the path of the .class files (a/b/C.class), and that using the package name / class name to derive a path is typically bad practice. Sets of class files / packages can be in multiple different class paths, which can be directories or jar files.

Get a resource using getResource()

Instead of explicitly writing the class name you could use


Declaring & Setting Variables in a Select Statement

From the searching I've done it appears you can not declare and set variables like this in Select statements. Is this right or am I missing something?

Within Oracle PL/SQL and SQL are two separate languages with two separate engines. You can embed SQL DML within PL/SQL, and that will get you variables. Such as the following anonymous PL/SQL block. Note the / at the end is not part of PL/SQL, but tells SQL*Plus to send the preceding block.

    v_Date1 date := to_date('03-AUG-2010', 'DD-Mon-YYYY');
    v_Count number;
    select count(*) into v_Count
    from Usage
    where UseTime > v_Date1;

The problem is that a block that is equivalent to your T-SQL code will not work:

SQL> declare 
  2      v_Date1 date := to_date('03-AUG-2010', 'DD-Mon-YYYY');
  3  begin
  4      select VisualId
  5      from Usage
  6      where UseTime > v_Date1;
  7  end;
  8  /
    select VisualId
ERROR at line 4:
ORA-06550: line 4, column 5:
PLS-00428: an INTO clause is expected in this SELECT statement

To pass the results of a query out of an PL/SQL, either an anonymous block, stored procedure or stored function, a cursor must be declared, opened and then returned to the calling program. (Beyond the scope of answering this question. EDIT: see Get resultset from oracle stored procedure)

The client tool that connects to the database may have it's own bind variables. In SQL*Plus:

SQL> -- SQL*Plus does not all date type in this context
SQL> -- So using varchar2 to hold text
SQL> variable v_Date1 varchar2(20)
SQL> -- use PL/SQL to set the value of the bind variable
SQL> exec :v_Date1 := '02-Aug-2010';

PL/SQL procedure successfully completed.

SQL> -- Converting to a date, since the variable is not yet a date.
SQL> -- Note the use of colon, this tells SQL*Plus that v_Date1
SQL> -- is a bind variable.
SQL> select VisualId
  2  from Usage
  3  where UseTime > to_char(:v_Date1, 'DD-Mon-YYYY');

no rows selected

Note the above is in SQLPlus, may not (probably won't) work in Toad PL/SQL developer, etc. The lines starting with variable and exec are SQLPlus commands. They are not SQL or PL/SQL commands. No rows selected because the table is empty.

how to find 2d array size in c++

#include <bits/stdc++.h>
using namespace std;

int main(int argc, char const *argv[])
    int arr[6][5] = {
    int rows = sizeof(arr)/sizeof(arr[0]);
    int cols = sizeof(arr[0])/sizeof(arr[0][0]);
    cout<<rows<<" "<<cols<<endl;
    return 0;

Output: 6 5

Remove the first character of a string

Depending on the structure of the string, you can use lstrip:

str = str.lstrip(':')

But this would remove all colons at the beginning, i.e. if you have ::foo, the result would be foo. But this function is helpful if you also have strings that do not start with a colon and you don't want to remove the first character then.

jQuery - Get Width of Element when Not Visible (Display: None)

jQuery(".megamenu li.level0 .dropdown-container .sub-column ul .level1").on("mouseover", function () {
    var sum = 0;
    jQuery(this).find('ul li.level2').each(function(){
    sum -= jQuery(this).height();
    jQuery(this).parent('ul').css('margin-top', sum / 1.8);

On hover we can calculate the list item height.

Convert UTC dates to local time in PHP

I store date in the DB in UTC format but then I show them to the final user in their local timezone

// retrieve
$d = (new \DateTime($val . ' UTC'))->format('U');
return date("Y-m-d H:i:s", $d);

Unable to add window -- token null is not valid; is your activity running?

In my case, I was inflating a PopupMenu at the very beginning of the activity i.e on onCreate()... I fixed it by putting it in a Handler

  new Handler().postDelayed(new Runnable() {
            public void run() {
                PopupMenu popuMenu=new PopupMenu(SplashScreen.this,binding.progressBar);