Programs & Examples On #File management

File Management relates to the efficient control over, usage of and access to files by users and computer operating systems

Remove all files in a directory

Please see my answer here:

https://stackoverflow.com/a/24844618/2293304

It's a long and ugly, but reliable and efficient solution.

It resolves a few problems which are not addressed by the other answerers:

  • It correctly handles symbolic links, including not calling shutil.rmtree() on a symbolic link (which will pass the os.path.isdir() test if it links to a directory).
  • It handles read-only files nicely.

What's the fastest way to delete a large folder in Windows?

use fastcopy, a free tool. it has a delete option that is a lot faster then the way windows deletes files.

How to pass multiple parameters in json format to a web service using jquery?

i have same issue and resolved by

 data: "Id1=" + id1 + "&Id2=" + id2

Change grid interval and specify tick labels in Matplotlib

A subtle alternative to MaxNoe's answer where you aren't explicitly setting the ticks but instead setting the cadence.

import matplotlib.pyplot as plt
from matplotlib.ticker import (AutoMinorLocator, MultipleLocator)

fig, ax = plt.subplots(figsize=(10, 8))

# Set axis ranges; by default this will put major ticks every 25.
ax.set_xlim(0, 200)
ax.set_ylim(0, 200)

# Change major ticks to show every 20.
ax.xaxis.set_major_locator(MultipleLocator(20))
ax.yaxis.set_major_locator(MultipleLocator(20))

# Change minor ticks to show every 5. (20/4 = 5)
ax.xaxis.set_minor_locator(AutoMinorLocator(4))
ax.yaxis.set_minor_locator(AutoMinorLocator(4))

# Turn grid on for both major and minor ticks and style minor slightly
# differently.
ax.grid(which='major', color='#CCCCCC', linestyle='--')
ax.grid(which='minor', color='#CCCCCC', linestyle=':')

Matplotlib Custom Grid

Convert String to double in Java

There is another way too.

Double temp = Double.valueOf(str);
number = temp.doubleValue();

Double is a class and "temp" is a variable. "number" is the final number you are looking for.

Get all column names of a DataTable into string array using (LINQ/Predicate)

Use

var arrayNames = (from DataColumn x in dt.Columns
                  select x.ColumnName).ToArray();

How to import js-modules into TypeScript file?

2021 Solution

If you're still getting this error message:

TS7016: Could not find a declaration file for module './myjsfile'

Then you might need to add the following to tsconfig.json

{
  "compilerOptions": {
    ...
    "allowJs": true,
    "checkJs": false,
    ...
  }
}

This prevents typescript from trying to apply module types to the imported javascript.

Is it possible to pass parameters programmatically in a Microsoft Access update query?

I just tested this and it works in Access 2010.

Say you have a SELECT query with parameters:

PARAMETERS startID Long, endID Long;
SELECT Members.*
FROM Members
WHERE (((Members.memberID) Between [startID] And [endID]));

You run that query interactively and it prompts you for [startID] and [endID]. That works, so you save that query as [MemberSubset].

Now you create an UPDATE query based on that query:

UPDATE Members SET Members.age = [age]+1
WHERE (((Members.memberID) In (SELECT memberID FROM [MemberSubset])));

You run that query interactively and again you are prompted for [startID] and [endID] and it works well, so you save it as [MemberSubsetUpdate].

You can run [MemberSubsetUpdate] from VBA code by specifying [startID] and [endID] values as parameters to [MemberSubsetUpdate], even though they are actually parameters of [MemberSubset]. Those parameter values "trickle down" to where they are needed, and the query does work without human intervention:

Sub paramTest()
    Dim qdf As DAO.QueryDef
    Set qdf = CurrentDb.QueryDefs("MemberSubsetUpdate")
    qdf!startID = 1  ' specify
    qdf!endID = 2    '     parameters
    qdf.Execute
    Set qdf = Nothing
End Sub

jQuery SVG, why can't I addClass?

Based on above answers I created the following API

/*
 * .addClassSVG(className)
 * Adds the specified class(es) to each of the set of matched SVG elements.
 */
$.fn.addClassSVG = function(className){
    $(this).attr('class', function(index, existingClassNames) {
        return ((existingClassNames !== undefined) ? (existingClassNames + ' ') : '') + className;
    });
    return this;
};

/*
 * .removeClassSVG(className)
 * Removes the specified class to each of the set of matched SVG elements.
 */
$.fn.removeClassSVG = function(className){
    $(this).attr('class', function(index, existingClassNames) {
        var re = new RegExp('\\b' + className + '\\b', 'g');
        return existingClassNames.replace(re, '');
    });
    return this;
};

When to use the different log levels

I think that SYSLOG levels NOTICE and ALERT/EMERGENCY are largely superfluous for application-level logging - while CRITICAL/ALERT/EMERGENCY may be useful alert levels for an operator that may trigger different actions and notifications, to an application admin it's all the same as FATAL. And I just cannot sufficiently distinguish between being given a notice or some information. If the information is not noteworthy, it's not really information :)

I like Jay Cincotta's interpretation best - tracing your code's execution is something very useful in tech support, and putting trace statements into the code liberally should be encouraged - especially in combination with a dynamic filtering mechanism for logging the trace messages from specific application components. However DEBUG level to me indicates that we're still in the process of figuring out what's going on - I see DEBUG level output as a development-only option, not as something that should ever show up in a production log.

There is however a logging level that I like to see in my error logs when wearing the hat of a sysadmin as much as that of tech support, or even developer: OPER, for OPERATIONAL messages. This I use for logging a timestamp, the type of operation invoked, the arguments supplied, possibly a (unique) task identifier, and task completion. It's used when e.g. a standalone task is fired off, something that is a true invocation from within the larger long-running app. It's the sort of thing I want always logged, no matter whether anything goes wrong or not, so I consider the level of OPER to be higher than FATAL, so you can only turn it off by going to totally silent mode. And it's much more than mere INFO log data - a log level often abused for spamming logs with minor operational messages of no historical value whatsoever.

As the case dictates this information may be directed to a separate invocation log, or may be obtained by filtering it out of a large log recording more information. But it's always needed, as historical info, to know what was being done - without descending to the level of AUDIT, another totally separate log level that has nothing to do with malfunctions or system operation, doesn't really fit within the above levels (as it needs its own control switch, not a severity classification) and which definitely needs its own separate log file.

Python: convert string from UTF-8 to Latin-1

If the previous answers do not solve your problem, check the source of the data that won't print/convert properly.

In my case, I was using json.load on data incorrectly read from file by not using the encoding="utf-8". Trying to de-/encode the resulting string to latin-1 just does not help...

How to compile and run C in sublime text 3?

The best way would be just to use a Makefile for your project and ST3 will automatically detect build system for your project. For example. If you press shift + ctrl/cmd +B you will see this: Make

Git's famous "ERROR: Permission to .git denied to user"

After Googling for few days, I found this is the only question similar to my situation.

However, I just solved the problem! So I am putting my answer here to help anyone else searching for this issue.

Here is what I did:

  1. Open "Keychain Access.app" (You can find it in Spotlight or LaunchPad)

  2. Select "All items" in Category

  3. Search "git"

  4. Delete every old & strange item

  5. Try to Push again and it just WORKED

Can't install APK from browser downloads

It shouldn't be HTTP headers if the file has been downloaded successfully and it's the same file that you can open from OI.

A shot in the dark, but could it be that you are not allowing installation from unknown sources, and that OI is somehow bypassing that?

Settings > Applications > Unknown sources...

Edit

Answer extracted from comments which worked. Ensure the Content-Type is set to application/vnd.android.package-archive

Change the Blank Cells to "NA"

My function takes into account factor, character vector and potential attributes, if you use haven or foreign package to read external files. Also it allows matching different self-defined na.strings. To transform all columns, simply use lappy: df[] = lapply(df, blank2na, na.strings=c('','NA','na','N/A','n/a','NaN','nan'))

See more the comments:

#' Replaces blank-ish elements of a factor or character vector to NA
#' @description Replaces blank-ish elements of a factor or character vector to NA
#' @param x a vector of factor or character or any type
#' @param na.strings case sensitive strings that will be coverted to NA. The function will do a trimws(x,'both') before conversion. If NULL, do only trimws, no conversion to NA.
#' @return Returns a vector trimws (always for factor, character) and NA converted (if matching na.strings). Attributes will also be kept ('label','labels', 'value.labels').
#' @seealso \code{\link{ez.nan2na}}
#' @export
blank2na = function(x,na.strings=c('','.','NA','na','N/A','n/a','NaN','nan')) {
    if (is.factor(x)) {
        lab = attr(x, 'label', exact = T)
        labs1 <- attr(x, 'labels', exact = T)
        labs2 <- attr(x, 'value.labels', exact = T)

        # trimws will convert factor to character
        x = trimws(x,'both')
        if (! is.null(lab)) lab = trimws(lab,'both')
        if (! is.null(labs1)) labs1 = trimws(labs1,'both')
        if (! is.null(labs2)) labs2 = trimws(labs2,'both')

        if (!is.null(na.strings)) {
            # convert to NA
            x[x %in% na.strings] = NA
            # also remember to remove na.strings from value labels 
            labs1 = labs1[! labs1 %in% na.strings]
            labs2 = labs2[! labs2 %in% na.strings]
        }

        # the levels will be reset here
        x = factor(x)

        if (! is.null(lab)) attr(x, 'label') <- lab
        if (! is.null(labs1)) attr(x, 'labels') <- labs1
        if (! is.null(labs2)) attr(x, 'value.labels') <- labs2
    } else if (is.character(x)) {
        lab = attr(x, 'label', exact = T)
        labs1 <- attr(x, 'labels', exact = T)
        labs2 <- attr(x, 'value.labels', exact = T)

        # trimws will convert factor to character
        x = trimws(x,'both')
        if (! is.null(lab)) lab = trimws(lab,'both')
        if (! is.null(labs1)) labs1 = trimws(labs1,'both')
        if (! is.null(labs2)) labs2 = trimws(labs2,'both')

        if (!is.null(na.strings)) {
            # convert to NA
            x[x %in% na.strings] = NA
            # also remember to remove na.strings from value labels 
            labs1 = labs1[! labs1 %in% na.strings]
            labs2 = labs2[! labs2 %in% na.strings]
        }

        if (! is.null(lab)) attr(x, 'label') <- lab
        if (! is.null(labs1)) attr(x, 'labels') <- labs1
        if (! is.null(labs2)) attr(x, 'value.labels') <- labs2
    } else {
        x = x
    }
    return(x)
}

Unable to resolve dependency for ':app@debug/compileClasspath': Could not resolve com.android.support:appcompat-v7:26.1.0

I ran into the same issue and adding mavenCentral() in the repositories block of my build.gradle file worked for me. I had Offline work unchecked and adding maven { url "https://maven.google.com" }. Adding this answer for the lost souls that find themselves at end of this thread.

Axios Delete request with body and headers?

So after a number of tries, I found it working.

Please follow the order sequence it's very important else it won't work

axios.delete(URL, {
  headers: {
    Authorization: authorizationToken
  },
  data: {
    source: source
  }
});

Mysql error 1452 - Cannot add or update a child row: a foreign key constraint fails

try this

SET foreign_key_checks = 0;

ALTER TABLE sourcecodes_tags ADD FOREIGN KEY (sourcecode_id) REFERENCES sourcecodes (id) ON DELETE CASCADE ON UPDATE CASCADE

SET foreign_key_checks = 1;

A general tree implementation?

node = { 'parent':0, 'left':0, 'right':0 }
import copy
root = copy.deepcopy(node)
root['parent'] = -1
left = copy

just to show another thought on implementation if you stick to the "OOP"

class Node:
    def __init__(self,data):
        self.data = data
        self.child = {}
    def append(self, title, child):
        self.child[title] = child

CEO = Node( ('ceo', 1000) )
CTO = ('cto',100)
CFO = ('cfo', 10)
CEO.append('left child', CTO)
CEO.append('right child', CFO)

print CEO.data
print ' ', CEO.child['left child']
print ' ', CEO.child['right child']

Convert string to Python class object?

I don't see why this wouldn't work. It's not as concrete as everyone else's answers but if you know the name of your class then it's enough.

def str_to_class(name):
    if name == "Foo":
        return Foo
    elif name == "Bar":
        return Bar

Error : java.lang.NoSuchMethodError: org.objectweb.asm.ClassWriter.<init>(I)V

The NoSuchMethodError javadoc says this:

Thrown if an application tries to call a specified method of a class (either static or instance), and that class no longer has a definition of that method.

Normally, this error is caught by the compiler; this error can only occur at run time if the definition of a class has incompatibly changed.

In your case, this Error is a strong indication that your webapp is using the wrong version of the JAR defining the org.objectweb.asm.* classes.

Plot two graphs in same plot in R

You could use the ggplotly() function from the plotly package to turn any of the gggplot2 examples here into an interactive plot, but I think this sort of plot is better without ggplot2:

# call Plotly and enter username and key
library(plotly)
x  <- seq(-2, 2, 0.05)
y1 <- pnorm(x)
y2 <- pnorm(x, 1, 1)

plot_ly(x = x) %>%
  add_lines(y = y1, color = I("red"), name = "Red") %>%
  add_lines(y = y2, color = I("green"), name = "Green")

enter image description here

MySQL "WITH" clause

Oracle does support WITH.

It would look like this.

WITH emps as (SELECT * FROM Employees)
SELECT * FROM emps WHERE ID < 20
UNION ALL
SELECT * FROM emps where Sex = 'F'

@ysth WITH is hard to google because it's a common word typically excluded from searches.

You'd want to look at the SELECT docs to see how subquery factoring works.

I know this doesn't answer the OP but I'm cleaning up any confusion ysth may have started.

Javac is not found

Start off by opening a cmd.exe session, changing directory to the "program files" directory that has the javac.exe executable and running .\javac.exe.

If that doesn't work, reinstall java. If that works, odds are you will find (in doing that task) that you've installed a 64 bit javac.exe, or a slightly different release number of javac.exe, or in a different drive, etc. and selecting the right entry in your path will become child's play.

Only use the semicolon between directories in the PATH environment variable, and remember that in some systems, you need to log out and log back in before the new environment variable is accessible to all environments.

Define preprocessor macro through CMake?

To do this for a specific target, you can do the following:

target_compile_definitions(my_target PRIVATE FOO=1 BAR=1)

You should do this if you have more than one target that you're building and you don't want them all to use the same flags. Also see the official documentation on target_compile_definitions.

When is null or undefined used in JavaScript?

Regarding this topic the specification (ecma-262) is quite clear

I found it really useful and straightforward, so that I share it: - Here you will find Equality algorithm - Here you will find Strict equality algorithm

I bumped into it reading "Abstract equality, strict equality, and same value" from mozilla developer site, section sameness.

I hope you find it useful.

Floating Point Exception C++ Why and what is it?

Problem is in the for loop in the code snippet:
for (i > 0; i--;)

Here, your intention seems to be entering the loop if (i > 0) and decrement the value of i by one after the completion of for loop.

Does it work like that? lets see.

Look at the for() loop syntax:

**for ( initialization; condition check; increment/decrement ) {  
    statements;  
}**

Initialization gets executed only once in the beginning of the loop. Pay close attention to ";" in your code snippet and map it with for loop syntax.

Initialization : i > 0 : Gets executed only once. Doesn't have any impact in your code.

Condition check : i -- : post decrement.

              Here, i is used for condition check and then it is decremented. 
              Decremented value will be used in statements within for loop. 
              This condition check is working as increment/decrement too in your code. 

Lets stop here and see floating point exception.

what is it? One easy example is Divide by 0. Same is happening with your code.

When i reaches 1 in condition check, condition check validates to be true.
Because of post decrement i will be 0 when it enters for loop.

Modulo operation at line #9 results in divide by zero operation.  

With this background you should be able to fix the problem in for loop.

Host binding and Host listening

This is the simple example to use both of them:

import {
  Directive, HostListener, HostBinding
}
from '@angular/core';

@Directive({
  selector: '[Highlight]'
})
export class HighlightDirective {
  @HostListener('mouseenter') mouseover() {
    this.backgroundColor = 'green';
  };

  @HostListener('mouseleave') mouseleave() {
    this.backgroundColor = 'white';
  }

  @HostBinding('style.backgroundColor') get setColor() {
     return this.backgroundColor;
  };

  private backgroundColor = 'white';
  constructor() {}

}

Introduction:

  1. HostListener can bind an event to the element.

  2. HostBinding can bind a style to the element.

  3. this is directive, so we can use it for

    Some Text
  4. So according to the debug, we can find that this div has been binded style = "background-color:white"

    Some Text
  5. we also can find that EventListener of this div has two event: mouseenter and mouseleave. So when we move the mouse into the div, the colour will become green, mouse leave, the colour will become white.

Angular CLI SASS options

ng set --global defaults.styleExt=scss is deprecated since ng6. You will get this message:

get/set have been deprecated in favor of the config command

You should use:

ng config schematics.@schematics/angular:component '{ styleext: "scss"}'

If you want to target a specific project (replace {project} with your project's name):

ng config projects.{project}.schematics.@schematics/angular:component '{ styleext: "scss"}'

R apply function with multiple parameters

Just pass var2 as an extra argument to one of the apply functions.

mylist <- list(a=1,b=2,c=3)
myfxn <- function(var1,var2){
  var1*var2
}
var2 <- 2

sapply(mylist,myfxn,var2=var2)

This passes the same var2 to every call of myfxn. If instead you want each call of myfxn to get the 1st/2nd/3rd/etc. element of both mylist and var2, then you're in mapply's domain.

Setting width and height

The below worked for me - but dont forget to put this in the "options" param.

var myChart = new Chart(ctx, {
type: 'line',
data: data,
options: {
    maintainAspectRatio: false,
    responsive:true,
    scales: {
        yAxes: [{
            ticks: {
                beginAtZero: true
            }
        }]
    }
}
});

How to retrieve Jenkins build parameters using the Groovy API?

In cases when a parameter name cannot be hardcoded I found this would be the simplest and best way to access parameters:

def myParam = env.getProperty(dynamicParamName)

In cases, when a parameter name is known and can be hardcoded the following 3 lines are equivalent:

def myParam = env.getProperty("myParamName")
def myParam = env.myParamName
def myParam = myParamName

LINQ to SQL - Left Outer Join with multiple join conditions

You need to introduce your join condition before calling DefaultIfEmpty(). I would just use extension method syntax:

from p in context.Periods
join f in context.Facts on p.id equals f.periodid into fg
from fgi in fg.Where(f => f.otherid == 17).DefaultIfEmpty()
where p.companyid == 100
select f.value

Or you could use a subquery:

from p in context.Periods
join f in context.Facts on p.id equals f.periodid into fg
from fgi in (from f in fg
             where f.otherid == 17
             select f).DefaultIfEmpty()
where p.companyid == 100
select f.value

How can I concatenate strings in VBA?

The main (very interesting) difference for me is that:
"string" & Null -> "string"
while
"string" + Null -> Null

But that's probably more useful in database apps like Access.

Send email from localhost running XAMMP in PHP using GMAIL mail server

Here's the link that gives me the answer:

[Install] the "fake sendmail for windows". If you are not using XAMPP you can download it here: http://glob.com.au/sendmail/sendmail.zip

[Modify] the php.ini file to use it (commented out the other lines):

[mail function]
; For Win32 only.
; SMTP = smtp.gmail.com
; smtp_port = 25

; For Win32 only.
; sendmail_from = <e-mail username>@gmail.com

; For Unix only. You may supply arguments as well (default: "sendmail -t -i").
sendmail_path = "C:\xampp\sendmail\sendmail.exe -t"

(ignore the "Unix only" bit, since we actually are using sendmail)

You then have to configure the "sendmail.ini" file in the directory where sendmail was installed:

[sendmail]

smtp_server=smtp.gmail.com
smtp_port=25
error_logfile=error.log
debug_logfile=debug.log
auth_username=<username>
auth_password=<password>
force_sender=<e-mail username>@gmail.com

To access a Gmail account protected by 2-factor verification, you will need to create an application-specific password. (source)

Disable browser's back button

There have been a few different implementations. There is a flash solution and some iframe/frame solutions for IE. Check out this

http://www.contentwithstyle.co.uk/content/fixing-the-back-button-and-enabling-bookmarking-for-ajax-apps

BTW: There are plenty of valid reasons to disable (or at least prevent 1 step) a back button -- look at gmail as an example which implements the hash solution discussed in the above article.

Google "how ajax broke the back button" and you'll find plenty of articles on user testing and the validity of disabling the back button.

How to mute an html5 video player using jQuery

Are you using the default controls boolean attribute on the video tag? If so, I believe all the supporting browsers have mute buttons. If you need to wire it up, set .muted to true on the element in javascript (use .prop for jquery because it's an IDL attribute.) The speaker icon on the volume control is the mute button on chrome,ff, safari, and opera for example

Javascript - check array for value

If you don't care about legacy browsers:

if ( bank_holidays.indexOf( '06/04/2012' ) > -1 )

if you do care about legacy browsers, there is a shim available on MDN. Otherwise, jQuery provides an equivalent function:

if ( $.inArray( '06/04/2012', bank_holidays ) > -1 )

What’s the difference between "Array()" and "[]" while declaring a JavaScript array?

The first one is the default object constructor call. You can use it's parameters if you want.

var array = new Array(5); //initialize with default length 5

The second one gives you the ability to create not empty array:

var array = [1, 2, 3]; // this array will contain numbers 1, 2, 3.

There can be only one auto column

CREATE TABLE book (
   id INT AUTO_INCREMENT primary key NOT NULL,
   accepted_terms BIT(1) NOT NULL,
   accepted_privacy BIT(1) NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=latin1

Change a web.config programmatically with C# (.NET)

This is a method that I use to update AppSettings, works for both web and desktop applications. If you need to edit connectionStrings you can get that value from System.Configuration.ConnectionStringSettings config = configFile.ConnectionStrings.ConnectionStrings["YourConnectionStringName"]; and then set a new value with config.ConnectionString = "your connection string";. Note that if you have any comments in the connectionStrings section in Web.Config these will be removed.

private void UpdateAppSettings(string key, string value)
{
    System.Configuration.Configuration configFile = null;
    if (System.Web.HttpContext.Current != null)
    {
        configFile =
            System.Web.Configuration.WebConfigurationManager.OpenWebConfiguration("~");
    }
    else
    {
        configFile =
            ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None);
    }
    var settings = configFile.AppSettings.Settings;
    if (settings[key] == null)
    {
        settings.Add(key, value);
    }
    else
    {
        settings[key].Value = value;
    }
    configFile.Save(ConfigurationSaveMode.Modified);
    ConfigurationManager.RefreshSection(configFile.AppSettings.SectionInformation.Name);
}

How do I break a string in YAML over multiple lines?

There are 5 6 NINE (or 63*, depending how you count) different ways to write multi-line strings in YAML.

TL;DR

  • Use > most of the time: interior line breaks are stripped out, although you get one at the end:

    key: >
      Your long
      string here.
    
  • Use | if you want those linebreaks to be preserved as \n (for instance, embedded markdown with paragraphs).

    key: |
      ### Heading
    
      * Bullet
      * Points
    
  • Use >- or |- instead if you don't want a linebreak appended at the end.

  • Use "..." if you need to split lines in the middle of words or want to literally type linebreaks as \n:

    key: "Antidisestab\
     lishmentarianism.\n\nGet on it."
    
  • YAML is crazy.

Block scalar styles (>, |)

These allow characters such as \ and " without escaping, and add a new line (\n) to the end of your string.

> Folded style removes single newlines within the string (but adds one at the end, and converts double newlines to singles):

Key: >
  this is my very very very
  long string

? this is my very very very long string\n

| Literal style turns every newline within the string into a literal newline, and adds one at the end:

Key: |
  this is my very very very 
  long string

? this is my very very very\nlong string\n

Here's the official definition from the YAML Spec 1.2

Scalar content can be written in block notation, using a literal style (indicated by “|”) where all line breaks are significant. Alternatively, they can be written with the folded style (denoted by “>”) where each line break is folded to a space unless it ends an empty or a more-indented line.

Block styles with block chomping indicator (>-, |-, >+, |+)

You can control the handling of the final new line in the string, and any trailing blank lines (\n\n) by adding a block chomping indicator character:

  • >, |: "clip": keep the line feed, remove the trailing blank lines.
  • >-, |-: "strip": remove the line feed, remove the trailing blank lines.
  • >+, |+: "keep": keep the line feed, keep trailing blank lines.

"Flow" scalar styles (, ", ')

These have limited escaping, and construct a single-line string with no new line characters. They can begin on the same line as the key, or with additional newlines first.

plain style (no escaping, no # or : combinations, limits on first character):

Key: this is my very very very 
  long string

double-quoted style (\ and " must be escaped by \, newlines can be inserted with a literal \n sequence, lines can be concatenated without spaces with trailing \):

Key: "this is my very very \"very\" loooo\
  ng string.\n\nLove, YAML."

"this is my very very \"very\" loooong string.\n\nLove, YAML."

single-quoted style (literal ' must be doubled, no special characters, possibly useful for expressing strings starting with double quotes):

Key: 'this is my very very "very"
  long string, isn''t it.'

"this is my very very \"very\" long string, isn't it."

Summary

In this table, _ means space character. \n means "newline character" (\n in JavaScript), except for the "in-line newlines" row, where it means literally a backslash and an n).

                      >     |            "     '     >-     >+     |-     |+
-------------------------|------|-----|-----|-----|------|------|------|------  
Trailing spaces   | Kept | Kept |     |     |     | Kept | Kept | Kept | Kept
Single newline => | _    | \n   | _   | _   | _   | _    |  _   | \n   | \n
Double newline => | \n   | \n\n | \n  | \n  | \n  | \n   |  \n  | \n\n | \n\n
Final newline  => | \n   | \n   |     |     |     |      |  \n  |      | \n
Final dbl nl's => |      |      |     |     |     |      | Kept |      | Kept  
In-line newlines  | No   | No   | No  | \n  | No  | No   | No   | No   | No
Spaceless newlines| No   | No   | No  | \   | No  | No   | No   | No   | No 
Single quote      | '    | '    | '   | '   | ''  | '    | '    | '    | '
Double quote      | "    | "    | "   | \"  | "   | "    | "    | "    | "
Backslash         | \    | \    | \   | \\  | \   | \    | \    | \    | \
" #", ": "        | Ok   | Ok   | No  | Ok  | Ok  | Ok   | Ok   | Ok   | Ok
Can start on same | No   | No   | Yes | Yes | Yes | No   | No   | No   | No
line as key       |

Examples

Note the trailing spaces on the line before "spaces."

- >
  very "long"
  'string' with

  paragraph gap, \n and        
  spaces.
- | 
  very "long"
  'string' with

  paragraph gap, \n and        
  spaces.
- very "long"
  'string' with

  paragraph gap, \n and        
  spaces.
- "very \"long\"
  'string' with

  paragraph gap, \n and        
  s\
  p\
  a\
  c\
  e\
  s."
- 'very "long"
  ''string'' with

  paragraph gap, \n and        
  spaces.'
- >- 
  very "long"
  'string' with

  paragraph gap, \n and        
  spaces.

[
  "very \"long\" 'string' with\nparagraph gap, \\n and         spaces.\n", 
  "very \"long\"\n'string' with\n\nparagraph gap, \\n and        \nspaces.\n", 
  "very \"long\" 'string' with\nparagraph gap, \\n and spaces.", 
  "very \"long\" 'string' with\nparagraph gap, \n and spaces.", 
  "very \"long\" 'string' with\nparagraph gap, \\n and spaces.", 
  "very \"long\" 'string' with\nparagraph gap, \\n and         spaces."
]

Block styles with indentation indicators

Just in case the above isn't enough for you, you can add a "block indentation indicator" (after your block chomping indicator, if you have one):

- >8
        My long string
        starts over here
- |+1
 This one
 starts here

Addendum

If you insert extra spaces at the start of not-the-first lines in Folded style, they will be kept, with a bonus newline. This doesn't happen with flow styles:

- >
    my long
      string
- my long
    string

? ["my long\n string\n", "my long string"]

I can't even.

*2 block styles, each with 2 possible block chomping indicators (or none), and with 9 possible indentation indicators (or none), 1 plain style and 2 quoted styles: 2 x (2 + 1) x (9 + 1) + 1 + 2 = 63

Some of this information has also been summarised here.

Iterating through array - java

You should definitely encapsulate this logic into a method.

There is no benefit to repeating identical code multiple times.

Also, if you place the logic in a method and it changes, you only need to modify your code in one place.

Whether or not you want to use a 3rd party library is an entirely different decision.

Using CookieContainer with WebClient class

I think there's cleaner way where you don't have to create a new webclient (and it'll work with 3rd party libraries as well)

internal static class MyWebRequestCreator
{
    private static IWebRequestCreate myCreator;

    public static IWebRequestCreate MyHttp
    {
        get
        {
            if (myCreator == null)
            {
                myCreator = new MyHttpRequestCreator();
            }
            return myCreator;
        }
    }

    private class MyHttpRequestCreator : IWebRequestCreate
    {
        public WebRequest Create(Uri uri)
        {
            var req = System.Net.WebRequest.CreateHttp(uri);
            req.CookieContainer = new CookieContainer();
            return req;
        }
    }
}

Now all you have to do is opt in for which domains you want to use this:

    WebRequest.RegisterPrefix("http://example.com/", MyWebRequestCreator.MyHttp);

That means ANY webrequest that goes to example.com will now use your custom webrequest creator, including the standard webclient. This approach means you don't have to touch all you code. You just call the register prefix once and be done with it. You can also register for "http" prefix to opt in for everything everywhere.

Best way to compare dates in Android

Your code could be reduced to

SimpleDateFormat sdf = new SimpleDateFormat("dd/MM/yyyy");
Date strDate = sdf.parse(valid_until);
if (new Date().after(strDate)) {
    catalog_outdated = 1;
}

or

SimpleDateFormat sdf = new SimpleDateFormat("dd/MM/yyyy");
Date strDate = sdf.parse(valid_until);
if (System.currentTimeMillis() > strDate.getTime()) {
    catalog_outdated = 1;
}

How to toggle (hide / show) sidebar div using jQuery

See this fiddle for a preview and check the documentation for jquerys toggle and animate methods.

$('#toggle').toggle(function(){
    $('#A').animate({width:0});
    $('#B').animate({left:0});
},function(){
    $('#A').animate({width:200});
    $('#B').animate({left:200});
});

Basically you animate on the properties that sets the layout.

A more advanced version:

$('#toggle').toggle(function(){
    $('#A').stop(true).animate({width:0});
    $('#B').stop(true).animate({left:0});
},function(){
    $('#A').stop(true).animate({width:200});
    $('#B').stop(true).animate({left:200});
})

This stops the previous animation, clears animation queue and begins the new animation.

How to display with n decimal places in Matlab

You can convert a number to a string with n decimal places using the SPRINTF command:

>> x = 1.23;
>> sprintf('%0.6f', x)

ans =

1.230000

>> x = 1.23456789;
>> sprintf('%0.6f', x)

ans =

1.234568

How to concatenate multiple lines of output to one line?

Probably the best way to do it is using 'awk' tool which will generate output into one line

$ awk ' /pattern/ {print}' ORS=' ' /path/to/file

It will merge all lines into one with space delimiter

Just disable scroll not hide it?

I like to stick to the "overflow: hidden" method and just add padding-right that's equal to the scrollbar width.

Get scrollbar width function, by lostsource.

function getScrollbarWidth() {
    var outer = document.createElement("div");
    outer.style.visibility = "hidden";
    outer.style.width = "100px";
    outer.style.msOverflowStyle = "scrollbar"; // needed for WinJS apps

    document.body.appendChild(outer);

    var widthNoScroll = outer.offsetWidth;
    // force scrollbars
    outer.style.overflow = "scroll";

    // add innerdiv
    var inner = document.createElement("div");
    inner.style.width = "100%";
    outer.appendChild(inner);        

    var widthWithScroll = inner.offsetWidth;

    // remove divs
    outer.parentNode.removeChild(outer);

    return widthNoScroll - widthWithScroll;
}

When showing the overlay, add "noscroll" class to html and add padding-right to body:

$(html).addClass("noscroll");
$(body).css("paddingRight", getScrollbarWidth() + "px");

When hiding, remove the class and padding:

$(html).removeClass("noscroll");
$(body).css("paddingRight", 0);

The noscroll style is just this:

.noscroll { overflow: hidden; }

Note that if you have any elements with position:fixed you need to add the padding to those elements too.

Comments in Android Layout xml

ctrl+shift+/ You can comment the code.

<!--    
     <View
          android:layout_marginTop="@dimen/d10dp"
          android:id="@+id/view1"
          android:layout_below="@+id/tv_change_password"
          android:layout_width="fill_parent"
          android:layout_height="1dp"
          android:background="#c0c0c0"/>-->

Run function from the command line

python -c 'from myfile import hello; hello()' where myfile must be replaced with the basename of your Python script. (E.g., myfile.py becomes myfile).

However, if hello() is your "permanent" main entry point in your Python script, then the usual way to do this is as follows:

def hello():
    print "Hi :)"

if __name__ == "__main__":
    hello()

This allows you to execute the script simply by running python myfile.py or python -m myfile.

Some explanation here: __name__ is a special Python variable that holds the name of the module currently being executed, except when the module is started from the command line, in which case it becomes "__main__".

How to select the last record of a table in SQL?

MS SQL Server has supported ANSI SQL FETCH FIRST for many years now:

SELECT * FROM TABLE
ORDER BY ID DESC 
OFFSET 0 ROWS FETCH FIRST 1 ROW ONLY

(Works with most modern databases.)

ldconfig error: is not a symbolic link

You need to include the path of the libraries inside /etc/ld.so.conf, and rerun ldconfig to upate the list

Other possibility is to include in the env variable LD_LIBRARY_PATH the path to your library, and rerun the executable.

check the symbolic links if they point to a valid library ...

You can add the path directly in /etc/ld.so.conf, without include...

run ldconfig -p to see whether your library is well included in the cache.

curl_init() function not working

For PHP 7 and Windows x64

libeay32.dll, libssh2.dll and ssleay32.dll should not be in apache/bin and should only exist in php directory and add php directory in system environment variable. This work for me.

Obvisouly in php.ini you should have enable php_curl.dll as well.

How to Set JPanel's Width and Height?

please, something went xxx*x, and that's not true at all, check that

JButton Size - java.awt.Dimension[width=400,height=40]
JPanel Size - java.awt.Dimension[width=640,height=480]
JFrame Size - java.awt.Dimension[width=646,height=505]

code (basic stuff from Trail: Creating a GUI With JFC/Swing , and yet I still satisfied that that would be outdated )

EDIT: forget setDefaultCloseOperation()

import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;

public class FrameSize {

    private JFrame frm = new JFrame();
    private JPanel pnl = new JPanel();
    private JButton btn = new JButton("Get ScreenSize for JComponents");

    public FrameSize() {
        btn.setPreferredSize(new Dimension(400, 40));
        btn.addActionListener(new ActionListener() {

            @Override
            public void actionPerformed(ActionEvent e) {
                System.out.println("JButton Size - " + btn.getSize());
                System.out.println("JPanel Size - " + pnl.getSize());
                System.out.println("JFrame Size - " + frm.getSize());
            }
        });
        pnl.setPreferredSize(new Dimension(640, 480));
        pnl.add(btn, BorderLayout.SOUTH);
        frm.add(pnl, BorderLayout.CENTER);
        frm.setLocation(150, 100);
        frm.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); // EDIT
        frm.setResizable(false);
        frm.pack();
        frm.setVisible(true);
    }

    public static void main(String[] args) {
        java.awt.EventQueue.invokeLater(new Runnable() {

            @Override
            public void run() {
                FrameSize fS = new FrameSize();
            }
        });
    }
}

Multi-line string with extra space (preserved indentation)

There are many ways to do it. For me, piping the indented string into sed works nicely.

printf_strip_indent() {
   printf "%s" "$1" | sed "s/^\s*//g" 
}

printf_strip_indent "this is line one
this is line two
this is line three" > "file.txt"

This answer was based on Mateusz Piotrowski's answer but refined a bit.

Oracle insert from select into table with more columns

Just add in the '0' in your select.

INSERT INTO table_name (a,b,c,d)
    SELECT
       other_table.a AS a,
       other_table.b AS b,
       other_table.c AS c,
       '0' AS d
    FROM other_table

Notice: Array to string conversion in

Even simpler:

$get = @mysql_query("SELECT money FROM players WHERE username = '" . $_SESSION['username'] . "'");

note the quotes around username in the $_SESSION reference.

Cell Style Alignment on a range

Don't use "Style:

worksheet.Cells[y,x].HorizontalAlignment = Microsoft.Office.Interop.Excel.XlHAlign.xlHAlignLeft;

Left Outer Join using + sign in Oracle 11g

I saw some contradictions in the answers above, I just tried the following on Oracle 12c and the following is correct :

LEFT OUTER JOIN

SELECT *
FROM A, B
WHERE A.column = B.column(+)

RIGHT OUTER JOIN

SELECT *
FROM A, B
WHERE B.column(+) = A.column

Where is web.xml in Eclipse Dynamic Web Project

If you don't see the web.xml file in WEB-INF folder,

enter image description here

- Select Deployment Descriptor and right click on it.
- Then select the Generate Deployment Descriptor Stub

enter image description here

Finally you get web.xml file.

enter image description here

Command not found error in Bash variable assignment

Drop the spaces around the = sign:

#!/bin/bash 
STR="Hello World" 
echo $STR 

Event system in Python

If I do code in pyQt I use QT sockets/signals paradigm, same is for django

If I'm doing async I/O I use native select module

If I'm usign a SAX python parser I'm using event API provided by SAX. So it looks like I'm victim of underlying API :-)

Maybe you should ask yourself what do you expect from event framework/module. My personal preference is to use Socket/Signal paradigm from QT. more info about that can be found here

How to compile the finished C# project and then run outside Visual Studio?

On your project folder, open up the bin\Debug subfolder and you'll see the compiled result.

How do I compile the asm generated by GCC?

Yes, gcc can also compile assembly source code. Alternatively, you can invoke as, which is the assembler. (gcc is just a "driver" program that uses heuristics to call C compiler, C++ compiler, assembler, linker, etc..)

what does Error "Thread 1:EXC_BAD_INSTRUCTION (code=EXC_I386_INVOP, subcode=0x0)" mean?

This line

secondNumber = Screen.text!.toInt()!

means: Get the Screen object, get the text property and please crash if it doesn't exist, then get the text converted to an integer, and please crash if it doesn't exist.

That's what the ! means: "I am sure this thing exists, so please crash if it doesn't". And crash is what it did.

BarCode Image Generator in Java

There is also this free API that you can use to make free barcodes in java.

Barbecue

How to Delete node_modules - Deep Nested Folder in Windows

Delete Deep Netsted Folder like node_modules in Windows

  1. Option 1

    Delete using rimraf NPM package

    • Open command prompt and change your directory to the folder where node_modules folder exists.

    • Run

      rimraf node_modules

    • Missing rimraf ERROR then Install

      npm install rimraf -g

    • When the installation completes, run

      rimraf node_modules

  2. Option 2:

    Detele without installing anything

    • Create a folder with name test in any Drive

      robocopy /MIR c:\test D:\UserData\FolderToDelete > NUL

    • delete the folder test and FolderToDelete as both are empty

Why this is an issue in windows?

One of the deep nested folder structure is node_modules, Windows can’t delete the folder as its name is too long. To solve this, Easy solution, install a node module RimRaf

asp.net Button OnClick event not firing

If you are using updatepanel on onclick event, this may happen.

Use 'EnableEventValidation="false"' in your page markup like this :

<%@ Page Language="C#" MasterPageFile="~/ars_home.master" AutoEventWireup="true" CodeFile="Transaction_Window.aspx.cs" Inherits="Transaction_Window" EnableEventValidation="false" %>

Hope this helps

How to make Bitmap compress without change the bitmap size?

If you are using PNG format then it will not compress your image because PNG is a lossless format. use JPEG for compressing your image and use 0 instead of 100 in quality.

Quality Accepts 0 - 100

0 = MAX Compression (Least Quality which is suitable for Small images)

100 = Least Compression (MAX Quality which is suitable for Big images)

What is the MySQL JDBC driver connection string?

Here's the documentation:

https://dev.mysql.com/doc/connector-j/en/connector-j-reference-configuration-properties.html

A basic connection string looks like:

jdbc:mysql://localhost:3306/dbname

The class.forName string is "com.mysql.jdbc.Driver", which you can find (edit: now on the same page).

How to hide Soft Keyboard when activity starts

If your application is targeting Android API Level 21 or more than there is a default method available.

editTextObj.setShowSoftInputOnFocus(false);

Make sure you have set below code in EditText XML tag.

<EditText  
    ....
    android:enabled="true"
    android:focusable="true" />

How to suppress Pandas Future warning ?

Warnings are annoying. As mentioned in other answers, you can suppress them using:

import warnings
warnings.simplefilter(action='ignore', category=FutureWarning)

But if you want to handle them one by one and you are managing a bigger codebase, it will be difficult to find the line of code which is causing the warning. Since warnings unlike errors don't come with code traceback. In order to trace warnings like errors, you can write this at the top of the code:

import warnings
warnings.filterwarnings("error")

But if the codebase is bigger and it is importing bunch of other libraries/packages, then all sort of warnings will start to be raised as errors. In order to raise only certain type of warnings (in your case, its FutureWarning) as error, you can write:

import warnings
warnings.simplefilter(action='error', category=FutureWarning)

return in for loop or outside loop

Now someone told me that this is not very good programming because I use the return statement inside a loop and this would cause garbage collection to malfunction.

That's a bunch of rubbish. Everything inside the method would be cleaned up unless there were other references to it in the class or elsewhere (a reason why encapsulation is important). As a rule of thumb, it's generally better to use one return statement simply because it is easier to figure out where the method will exit.

Personally, I would write:

Boolean retVal = false;
for(int i=0; i<array.length; ++i){
    if(array[i]==valueToFind) {
        retVal = true;
        break; //Break immediately helps if you are looking through a big array
    }
}
return retVal;

JAX-RS / Jersey how to customize error handling?

You could also write a reusable class for QueryParam-annotated variables

public class DateParam {
  private SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd");

  private Calendar date;

  public DateParam(String in) throws WebApplicationException {
    try {
      date = Calendar.getInstance();
      date.setTime(format.parse(in));
    }
    catch (ParseException exception) {
      throw new WebApplicationException(400);
    }
  }
  public Calendar getDate() {
    return date;
  }
  public String format() {
    return format.format(value.getTime());
  }
}

then use it like this:

private @QueryParam("from") DateParam startDateParam;
private @QueryParam("to") DateParam endDateParam;
// ...
startDateParam.getDate();

Although the error handling is trivial in this case (throwing a 400 response), using this class allows you to factor-out parameter handling in general which might include logging etc.

The POM for project is missing, no dependency information available

Change:

<!-- ANT4X -->
<dependency>
  <groupId>net.sourceforge</groupId>
  <artifactId>ant4x</artifactId>
  <version>${net.sourceforge.ant4x-version}</version>
  <scope>provided</scope>
</dependency>

To:

<!-- ANT4X -->
<dependency>
  <groupId>net.sourceforge.ant4x</groupId>
  <artifactId>ant4x</artifactId>
  <version>${net.sourceforge.ant4x-version}</version>
  <scope>provided</scope>
</dependency>

The groupId of net.sourceforge was incorrect. The correct value is net.sourceforge.ant4x.

How to POST a FORM from HTML to ASPX page

Are you sure your HTML form is correct, and does, in fact, do an HTTP POST? I would suggest running Fiddler2, and then trying to log in via your Login.aspx, then the remote HTML site, and then comparing the requests that are sent to the server. For me, ASP.Net always worked fine -- if HTTP request contains a valid POST, I can get to values using Request.Form...

Catch a thread's exception in the caller thread in Python

This was a nasty little problem, and I'd like to throw my solution in. Some other solutions I found (async.io for example) looked promising but also presented a bit of a black box. The queue / event loop approach sort of ties you to a certain implementation. The concurrent futures source code, however, is around only 1000 lines, and easy to comprehend. It allowed me to easily solve my problem: create ad-hoc worker threads without much setup, and to be able to catch exceptions in the main thread.

My solution uses the concurrent futures API and threading API. It allows you to create a worker which gives you both the thread and the future. That way, you can join the thread to wait for the result:

worker = Worker(test)
thread = worker.start()
thread.join()
print(worker.future.result())

...or you can let the worker just send a callback when done:

worker = Worker(test)
thread = worker.start(lambda x: print('callback', x))

...or you can loop until the event completes:

worker = Worker(test)
thread = worker.start()

while True:
    print("waiting")
    if worker.future.done():
        exc = worker.future.exception()
        print('exception?', exc)
        result = worker.future.result()
        print('result', result)           
        break
    time.sleep(0.25)

Here's the code:

from concurrent.futures import Future
import threading
import time

class Worker(object):
    def __init__(self, fn, args=()):
        self.future = Future()
        self._fn = fn
        self._args = args

    def start(self, cb=None):
        self._cb = cb
        self.future.set_running_or_notify_cancel()
        thread = threading.Thread(target=self.run, args=())
        thread.daemon = True #this will continue thread execution after the main thread runs out of code - you can still ctrl + c or kill the process
        thread.start()
        return thread

    def run(self):
        try:
            self.future.set_result(self._fn(*self._args))
        except BaseException as e:
            self.future.set_exception(e)

        if(self._cb):
            self._cb(self.future.result())

...and the test function:

def test(*args):
    print('args are', args)
    time.sleep(2)
    raise Exception('foo')

How to sum all the values in a dictionary?

You can get a generator of all the values in the dictionary, then cast it to a list and use the sum() function to get the sum of all the values.

Example:

c={"a":123,"b":4,"d":4,"c":-1001,"x":2002,"y":1001}

sum(list(c.values()))

How do you read CSS rule values with JavaScript?

This version will go through all of the stylesheets on a page. For my needs, the styles were usually in the 2nd to last of the 20+ stylesheets, so I check them backwards.

    var getStyle = function(className){
        var x, sheets,classes;
        for( sheets=document.styleSheets.length-1; sheets>=0; sheets-- ){
            classes = document.styleSheets[sheets].rules || document.styleSheets[sheets].cssRules;
            for(x=0;x<classes.length;x++) {
                if(classes[x].selectorText===className) {
                    return  (classes[x].cssText ? classes[x].cssText : classes[x].style.cssText);
                }
            }
        }
        return false;
    };

Ignore cells on Excel line graph

Not for blanks in the middle of a range, but this works for a complex chart from a start date until infinity (ie no need to adjust the chart's data source each time informatiom is added), without showing any lines for dates that have not yet been entered. As you add dates and data to the spreadsheet, the chart expands. Without it, the chart has a brain hemorrhage.

So, to count a complex range of conditions over an extended period of time but only if the date of the events is not blank :

=IF($B6<>"",(COUNTIF($O6:$O6,Q$5)),"") returns “#N/A” if there is no date in column B.

In other words, "count apples or oranges or whatever in column O (as determined by what is in Q5) but only if column B (the dates) is not blank". By returning “#N/A”, the chart will skip the "blank" rows (blank as in a zero value or rather "#N/A").

From that table of returned values you can make a chart from a date in the past to infinity

How to check for valid email address?

Use this filter mask on email input: emailMask: /[\w.\-@'"!#$%&'*+/=?^_{|}~]/i`

How do you add a timer to a C# console application

You can also create your own (if unhappy with the options available).

Creating your own Timer implementation is pretty basic stuff.

This is an example for an application that needed COM object access on the same thread as the rest of my codebase.

/// <summary>
/// Internal timer for window.setTimeout() and window.setInterval().
/// This is to ensure that async calls always run on the same thread.
/// </summary>
public class Timer : IDisposable {

    public void Tick()
    {
        if (Enabled && Environment.TickCount >= nextTick)
        {
            Callback.Invoke(this, null);
            nextTick = Environment.TickCount + Interval;
        }
    }

    private int nextTick = 0;

    public void Start()
    {
        this.Enabled = true;
        Interval = interval;
    }

    public void Stop()
    {
        this.Enabled = false;
    }

    public event EventHandler Callback;

    public bool Enabled = false;

    private int interval = 1000;

    public int Interval
    {
        get { return interval; }
        set { interval = value; nextTick = Environment.TickCount + interval; }
    }

    public void Dispose()
    {
        this.Callback = null;
        this.Stop();
    }

}

You can add events as follows:

Timer timer = new Timer();
timer.Callback += delegate
{
    if (once) { timer.Enabled = false; }
    Callback.execute(callbackId, args);
};
timer.Enabled = true;
timer.Interval = ms;
timer.Start();
Window.timers.Add(Environment.TickCount, timer);

To make sure the timer works you need to create an endless loop as follows:

while (true) {
     // Create a new list in case a new timer
     // is added/removed during a callback.
     foreach (Timer timer in new List<Timer>(timers.Values))
     {
         timer.Tick();
     }
}

Should I use the datetime or timestamp data type in MySQL?

2016 +: what I advise is to set your Mysql timezone to UTC and use DATETIME:

Any recent front-end framework (Angular 1/2, react, Vue,...) can easily and automatically convert your UTC datetime to local time.

Additionally:

(Unless you are likely to change the timezone of your servers)


Example with AngularJs

// back-end: format for angular within the sql query
SELECT DATE_FORMAT(my_datetime, "%Y-%m-%dT%TZ")...

// font-end Output the localised time
{{item.my_datetime | date :'medium' }}

All localised time format available here: https://docs.angularjs.org/api/ng/filter/date

CSS force image resize and keep aspect ratio

Fullscreen presentation:

img[data-attribute] {height: 100vh;}

Keep in mind that if the view-port height is greater than the image the image will naturally degrade relative to the difference.

Meaning of 'const' last in a function declaration of a class?

when you use const in the method signature (like your said: const char* foo() const;) you are telling the compiler that memory pointed to by this can't be changed by this method (which is foo here).

How do I integrate Ajax with Django applications?

Further from yuvi's excellent answer, I would like to add a small specific example on how to deal with this within Django (beyond any js that will be used). The example uses AjaxableResponseMixin and assumes an Author model.

import json

from django.http import HttpResponse
from django.views.generic.edit import CreateView
from myapp.models import Author

class AjaxableResponseMixin(object):
    """
    Mixin to add AJAX support to a form.
    Must be used with an object-based FormView (e.g. CreateView)
    """
    def render_to_json_response(self, context, **response_kwargs):
        data = json.dumps(context)
        response_kwargs['content_type'] = 'application/json'
        return HttpResponse(data, **response_kwargs)

    def form_invalid(self, form):
        response = super(AjaxableResponseMixin, self).form_invalid(form)
        if self.request.is_ajax():
            return self.render_to_json_response(form.errors, status=400)
        else:
            return response

    def form_valid(self, form):
        # We make sure to call the parent's form_valid() method because
        # it might do some processing (in the case of CreateView, it will
        # call form.save() for example).
        response = super(AjaxableResponseMixin, self).form_valid(form)
        if self.request.is_ajax():
            data = {
                'pk': self.object.pk,
            }
            return self.render_to_json_response(data)
        else:
            return response

class AuthorCreate(AjaxableResponseMixin, CreateView):
    model = Author
    fields = ['name']

Source: Django documentation, Form handling with class-based views

The link to version 1.6 of Django is no longer available updated to version 1.11

Turning Sonar off for certain code

You can annotate a class or a method with SuppressWarnings

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

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

ERROR Source option 1.5 is no longer supported. Use 1.6 or later

I got this error: "Source option 5 is no longer supported. Use 6 or later" after I changed the pom.xml

<java.version>7</java.version>

to

<java.version>11</java.version>

Later to realise the property was used with a dash insteal of a dot:

  <source>${java-version}</source>
  <target>${java-version}</target>

(swearings), I replaced the dot with a dash and the error went away:

<java-version>11</javaversion>

Find html label associated with a given input

It is actually far easier to add an id to the label in the form itself, for example:

<label for="firstName" id="firstNameLabel">FirstName:</label>

<input type="text" id="firstName" name="firstName" class="input_Field" 
       pattern="^[a-zA-Z\s\-]{2,25}$" maxlength="25"
       title="Alphabetic, Space, Dash Only, 2-25 Characters Long" 
       autocomplete="on" required
/>

Then, you can simply use something like this:

if (myvariableforpagelang == 'es') {
   // set field label to spanish
   document.getElementById("firstNameLabel").innerHTML = "Primer Nombre:";
   // set field tooltip (title to spanish
   document.getElementById("firstName").title = "Alfabética, espacio, guión Sólo, 2-25 caracteres de longitud";
}

The javascript does have to be in a body onload function to work.

Just a thought, works beautifully for me.

How do I lock the orientation to portrait mode in a iPhone Web Application?

// CSS hack to prevent layout breaking in landscape
// e.g. screens larger than 320px  
html {
  width: 320px;
  overflow-x: hidden;
}

This, or a similar CSS solution, will at least preserve your layout if that is what you are after.

The root solution is accounting for device's capabilities rather than attempting to limit them. If the device doesn't allow you the appropriate limitation than a simple hack is your best bet since the design is essentially incomplete. The simpler the better.

display: inline-block extra margin

For the record, that margin and padding resetting didn't do the trick for me, but this quote from one of the comments above turned out to be crucial and solved the issue for me: "If i put the divs on the same line it margin disappears."

How to check if android checkbox is checked within its onClick method (declared in XML)?

You can try this code:

public void itemClicked(View v) {
 //code to check if this checkbox is checked!
 if(((Checkbox)v).isChecked()){
   // code inside if
 }
}

Disable copy constructor

You can make the copy constructor private and provide no implementation:

private:
    SymbolIndexer(const SymbolIndexer&);

Or in C++11, explicitly forbid it:

SymbolIndexer(const SymbolIndexer&) = delete;

How to select min and max values of a column in a datatable?

int minAccountLevel = int.MaxValue;
int maxAccountLevel = int.MinValue;
foreach (DataRow dr in table.Rows)
{
    int accountLevel = dr.Field<int>("AccountLevel");
    minAccountLevel = Math.Min(minAccountLevel, accountLevel);
    maxAccountLevel = Math.Max(maxAccountLevel, accountLevel);
}

Yes, this really is the fastest way. Using the Linq Min and Max extensions will always be slower because you have to iterate twice. You could potentially use Linq Aggregate, but the syntax isn't going to be much prettier than this already is.

Unique Key constraints for multiple columns in Entity Framework

With Entity Framework 6.1, you can now do this:

[Index("IX_FirstAndSecond", 1, IsUnique = true)]
public int FirstColumn { get; set; }

[Index("IX_FirstAndSecond", 2, IsUnique = true)]
public int SecondColumn { get; set; }

The second parameter in the attribute is where you can specify the order of the columns in the index.
More information: MSDN

How do I change the figure size with subplots?

Alternatively, create a figure() object using the figsize argument and then use add_subplot to add your subplots. E.g.

import matplotlib.pyplot as plt
import numpy as np

f = plt.figure(figsize=(10,3))
ax = f.add_subplot(121)
ax2 = f.add_subplot(122)
x = np.linspace(0,4,1000)
ax.plot(x, np.sin(x))
ax2.plot(x, np.cos(x), 'r:')

Simple Example

Benefits of this method are that the syntax is closer to calls of subplot() instead of subplots(). E.g. subplots doesn't seem to support using a GridSpec for controlling the spacing of the subplots, but both subplot() and add_subplot() do.

Error "can't use subversion command line client : svn" when opening android project checked out from svn

If you are using ubuntu, check weather subversion is installed or not.

If not then install through command line as

sudo apt-get install subversion

and check following configurations are selected

enter image description here

How do I add a submodule to a sub-directory?

For those of you who share my weird fondness of manually editing config files, adding (or modifying) the following would also do the trick.

.git/config (personal config)

[submodule "cookbooks/apt"]
    url = https://github.com/opscode-cookbooks/apt

.gitmodules (committed shared config)

[submodule "cookbooks/apt"]
    path = cookbooks/apt
    url = https://github.com/opscode-cookbooks/apt

See this as well - difference between .gitmodules and specifying submodules in .git/config?

How to use stringstream to separate comma separated strings

#include <iostream>
#include <sstream>

std::string input = "abc,def,ghi";
std::istringstream ss(input);
std::string token;

while(std::getline(ss, token, ',')) {
    std::cout << token << '\n';
}

abc
def
ghi

How to edit the size of the submit button on a form?

just use style attribute with height and width option

<input type="submit" id="search" value="Search"  style="height:50px; width:50px" />

How do you disable browser Autocomplete on web form field / input tag?

try these too if just autocomplete="off" doesn't work:

autocorrect="off" autocapitalize="off" autocomplete="off"

Confused about stdin, stdout and stderr?

Using ps -aux reveals current processes, all of which are listed in /proc/ as /proc/(pid)/, by calling cat /proc/(pid)/fd/0 it prints anything that is found in the standard output of that process I think. So perhaps,

/proc/(pid)/fd/0 - Standard Output File
/proc/(pid)/fd/1 - Standard Input File
/proc/(pid)/fd/2 - Standard Error File

for examplemy terminal window

But only worked this well for /bin/bash other processes generally had nothing in 0 but many had errors written in 2

Reloading .env variables without restarting server (Laravel 5, shared hosting)

I know this is old, but for local dev, this is what got things back to a production .env file:

rm bootstrap/cache/config.php

then

php artisan config:cache
php artisan config:clear
php artisan cache:clear

PowerShell To Set Folder Permissions

In case you had to deal with a lot of subfolders contatining subfolders and other recursive stuff. Small improvment of @Mike L'Angelo:

$mypath = "path_to_folder"
$myacl = Get-Acl $mypath
$myaclentry = "username","FullControl","Allow"
$myaccessrule = New-Object System.Security.AccessControl.FileSystemAccessRule($myaclentry)
$myacl.SetAccessRule($myaccessrule)
Get-ChildItem -Path "$mypath" -Recurse -Force | Set-Acl -AclObject $myacl -Verbose

Verbosity is optional in the last line

How to print a specific row of a pandas DataFrame?

If you want to display at row=159220

row=159220

#To display in a table format
display(res.loc[row:row])
display(res.iloc[row:row+1])

#To display in print format
display(res.loc[row])
display(res.iloc[row])

Calculate the execution time of a method

If you are interested in understand performance, the best answer is to use a profiler.

Otherwise, System.Diagnostics.StopWatch provides a high resolution timer.

How to display line numbers in 'less' (GNU)

From the manual:

-N or --LINE-NUMBERS Causes a line number to be displayed at the beginning of each line in the display.

You can also toggle line numbers without quitting less by typing -N.

It is possible to toggle any of less's command line options in this way.

No input file specified

GoDaddy is currently (Feb '13) supporting modification of FastCGI for some accounts using PHP 5.2.x or earlier. See GoDaddy article "Disabling FastCGI in Your Hosting Account".
(In my case, this is apparently necessary to help get the current version of LimeSurvey (2.0) towards a running state.)

Docker is installed but Docker Compose is not ? why?

I'm on debian, I found something quite natural to do :

apt-get install docker-compose

and it did the job (not tested on centos)

How to run mysql command on bash?

This one worked, double quotes when $user and $password are outside single quotes. Single quotes when inside a single quote statement.

mysql --user="$user" --password="$password" --database="$user" --execute='DROP DATABASE '$user'; CREATE DATABASE '$user';'

Remove Item from ArrayList

String[] mString = new String[] {"B", "D", "F"};

for (int j = 0; j < mString.length-1; j++) {
        List_Of_Array.remove(mString[j]);
}

plain count up timer in javascript

Check this:

_x000D_
_x000D_
var minutesLabel = document.getElementById("minutes");_x000D_
var secondsLabel = document.getElementById("seconds");_x000D_
var totalSeconds = 0;_x000D_
setInterval(setTime, 1000);_x000D_
_x000D_
function setTime() {_x000D_
  ++totalSeconds;_x000D_
  secondsLabel.innerHTML = pad(totalSeconds % 60);_x000D_
  minutesLabel.innerHTML = pad(parseInt(totalSeconds / 60));_x000D_
}_x000D_
_x000D_
function pad(val) {_x000D_
  var valString = val + "";_x000D_
  if (valString.length < 2) {_x000D_
    return "0" + valString;_x000D_
  } else {_x000D_
    return valString;_x000D_
  }_x000D_
}
_x000D_
<label id="minutes">00</label>:<label id="seconds">00</label>
_x000D_
_x000D_
_x000D_

download a file from Spring boot rest service

I want to share a simple approach for downloading files with JavaScript (ES6), React and a Spring Boot backend:

  1. Spring boot Rest Controller

Resource from org.springframework.core.io.Resource

    @SneakyThrows
    @GetMapping("/files/{filename:.+}/{extraVariable}")
    @ResponseBody
    public ResponseEntity<Resource> serveFile(@PathVariable String filename, @PathVariable String extraVariable) {

        Resource file = storageService.loadAsResource(filename, extraVariable);
        return ResponseEntity.ok()
               .header(HttpHeaders.CONTENT_DISPOSITION, "attachment; filename=\"" + file.getFilename() + "\"")
               .body(file);
    }
  1. React, API call using AXIOS

Set the responseType to arraybuffer to specify the type of data contained in the response.

export const DownloadFile = (filename, extraVariable) => {
let url = 'http://localhost:8080/files/' + filename + '/' + extraVariable;
return axios.get(url, { responseType: 'arraybuffer' }).then((response) => {
    return response;
})};

Final step > downloading
with the help of js-file-download you can trigger browser to save data to file as if it was downloaded.

DownloadFile('filename.extension', 'extraVariable').then(
(response) => {
    fileDownload(response.data, filename);
}
, (error) => {
    // ERROR 
});

New lines inside paragraph in README.md

Interpreting newlines as <br /> used to be a feature of Github-flavored markdown, but the most recent help document no longer lists this feature.

Fortunately, you can do it manually. The easiest way is to ensure that each line ends with two spaces. So, change

a
b
c

into

a__
b__
c

(where _ is a blank space).

Or, you can add explicit <br /> tags.

a <br />
b <br />
c

Android: Use a SWITCH statement with setOnClickListener/onClick for more than 1 button?

inside OnCreate method :-

{

    Button b = (Button)findViewById(R.id.button1);
    b.setOnClickListener((View.OnClickListener)this);

    b = (Button)findViewById(R.id.button2);
    b.setOnClickListener((View.OnClickListener)this);
} 

@Override
public void OnClick(View v){

    switch(v.getId()){
         case R.id.button1:
             //whatever
             break;

         case R.id.button2:
             //whatever
             break;
}

Does Go have "if x in" construct similar to Python?

Another solution if the list contains static values.

eg: checking for a valid value from a list of valid values:

func IsValidCategory(category string) bool {
    switch category {
    case
        "auto",
        "news",
        "sport",
        "music":
        return true
    }
    return false
}

jQuery datepicker to prevent past date

//disable future dates

$('#datetimepicker1').datetimepicker({
            format: 'DD-MM-YYYY',
            maxDate: new Date
        }); 

//disable past dates

 $('#datetimepicker2').datetimepicker({
        format: 'DD-MM-YYYY',
        minDate: new Date
    });

Angular 2 Scroll to top on Route Change

You can also use scrollOffset in Route.ts. Ref. Router ExtraOptions

@NgModule({
  imports: [
    SomeModule.forRoot(
      SomeRouting,
      {
        scrollPositionRestoration: 'enabled',
        scrollOffset:[0,0]
      })],
  exports: [RouterModule]
})

Creating a new empty branch for a new project

Make an empty new branch like this:

true | git mktree | xargs git commit-tree | xargs git branch proj-doc

If your proj-doc files are already in a commit under a single subdir you can make the new branch this way:

git commit-tree thatcommit:path/to/dir | xargs git branch proj-doc

which might be more convenient than git branch --orphan if that would leave you with a lot of git rm and git mving to do.

Try

git branch --set-upstream proj-doc origin/proj-doc

and see if that helps with your fetching-too-much problem. Also if you really only want to fetch a single branch it's safest to just specify it on the commandline.

Capturing count from an SQL query

You'll get converting errors with:

cmd.CommandText = "SELECT COUNT(*) FROM table_name";
Int32 count = (Int32) cmd.ExecuteScalar();

Use instead:

string stm = "SELECT COUNT(*) FROM table_name WHERE id="+id+";";
MySqlCommand cmd = new MySqlCommand(stm, conn);
Int32 count = Convert.ToInt32(cmd.ExecuteScalar());
if(count > 0){
    found = true; 
} else {
    found = false; 
}

matplotlib: plot multiple columns of pandas data frame on the bar chart

Although the accepted answer works fine, since v0.21.0rc1 it gives a warning

UserWarning: Pandas doesn't allow columns to be created via a new attribute name

Instead, one can do

df[["X", "A", "B", "C"]].plot(x="X", kind="bar")

Escape text for HTML

Didn't see this here

System.Web.HttpUtility.JavaScriptStringEncode("Hello, this is Satan's Site")

it was the only thing that worked (asp 4.0+) when dealing with html like this. The&apos; gets rendered as ' (using htmldecode) in the html, causing it to fail:

<a href="article.aspx?id=268" onclick="tabs.open('modules/xxx/id/268', 'It&apos;s Allstars'); return false;">It's Allstars</a>

What is the difference between CMD and ENTRYPOINT in a Dockerfile?

Most people explain it perfectly here, so I won't repeat all the answers. But to get a good feeling I would suggest testing it yourself by looking at the processes in the container.

Create a tiny Dockerfile of the form:

FROM ubuntu:latest
CMD /bin/bash

Build it, run it in with docker run -it theimage and run ps -eo ppid,pid,args in the container. Compare this output to the output you receive from ps when using:

  • docker run -it theimage bash
  • Rebuilding the image but with ENTRYPOINT /bin/bash and running it in both ways
  • Using CMD ["/bin/bash"]
  • ...

This way you will easily see the differences between all possible methods for yourself.

How to search if dictionary value contains certain string with Python

import re
for i in range(len(myDict.values())):
     for j in range(len(myDict.values()[i])):
             match=re.search(r'Mary', myDict.values()[i][j])
             if match:
                     print match.group() #Mary
                     print myDict.keys()[i] #firstName
                     print myDict.values()[i][j] #Mary-Ann

Passing an array to a query using a WHERE clause

Because the original question relates to an array of numbers and I am using an array of strings I couldn't make the given examples work.

I found that each string needed to be encapsulated in single quotes to work with the IN() function.

Here is my solution

foreach($status as $status_a) {
        $status_sql[] = '\''.$status_a.'\'';
    }
    $status = implode(',',$status_sql);

$sql = mysql_query("SELECT * FROM table WHERE id IN ($status)");

As you can see the first function wraps each array variable in single quotes (\') and then implodes the array.

NOTE: $status does not have single quotes in the SQL statement.

There is probably a nicer way to add the quotes but this works.

What is the most elegant way to check if all values in a boolean array are true?

This is probably not faster, and definitely not very readable. So, for the sake of colorful solutions...

int i = array.length()-1;
for(; i > -1 && array[i]; i--);
return i==-1

VSCode single to double quote automatic replace

There only solution that worked for me: and only for Angular Projects:

Just go into your project ".editorconfig" file and paste 'quote_type = single'. Hope it should work for you as well.

Display List in a View MVC

Your action method considers model type asList<string>. But, in your view you are waiting for IEnumerable<Standings.Models.Teams>. You can solve this problem with changing the model in your view to List<string>.

But, the best approach would be to return IEnumerable<Standings.Models.Teams> as a model from your action method. Then you haven't to change model type in your view.

But, in my opinion your models are not correctly implemented. I suggest you to change it as:

public class Team
{
    public int Position { get; set; }
    public string HomeGround {get; set;}
    public string NickName {get; set;}
    public int Founded { get; set; }
    public string Name { get; set; }
}

Then you must change your action method as:

public ActionResult Index()
{
    var model = new List<Team>();

    model.Add(new Team { Name = "MU"});
    model.Add(new Team { Name = "Chelsea"});
    ...

    return View(model);
}

And, your view:

@model IEnumerable<Standings.Models.Team>

@{
     ViewBag.Title = "Standings";
}

@foreach (var item in Model)
{
    <div>
        @item.Name
        <hr />
    </div>
}

How to restart tomcat 6 in ubuntu

if you are using extracted tomcat then,

startup.sh and shutdown.sh are two script located in TOMCAT/bin/ to start and shutdown tomcat, You could use that

if tomcat is installed then

/etc/init.d/tomcat5.5 start
/etc/init.d/tomcat5.5 stop
/etc/init.d/tomcat5.5 restart

OpenCV resize fails on large image with "error: (-215) ssize.area() > 0 in function cv::resize"

I know this is a very old thread but I had the same problem which was due spaces in the images names.

e.g.

Image name: "hello o.jpg"

weirdly, by removing the spaces the function worked just fine.

Image name: "hello_o.jpg"

How to return the output of stored procedure into a variable in sql server

That depends on the nature of the information you want to return.

If it is a single integer value, you can use the return statement

 create proc myproc
 as 
 begin
     return 1
 end
 go
 declare @i int
 exec @i = myproc

If you have a non integer value, or a number of scalar values, you can use output parameters

create proc myproc
  @a int output,
  @b varchar(50) output
as
begin
  select @a = 1, @b='hello'
end
go
declare @i int, @j varchar(50)
exec myproc @i output, @j output

If you want to return a dataset, you can use insert exec

create proc myproc
as 
begin
     select name from sysobjects
end
go

declare @t table (name varchar(100))
insert @t (name)
exec myproc

You can even return a cursor but that's just horrid so I shan't give an example :)

How do I check if a SQL Server text column is empty?

To get only empty values (and not null values):

SELECT * FROM myTable WHERE myColumn = ''

To get both null and empty values:

SELECT * FROM myTable WHERE myColumn IS NULL OR myColumn = ''

To get only null values:

SELECT * FROM myTable WHERE myColumn IS NULL

To get values other than null and empty:

SELECT * FROM myTable WHERE myColumn <> ''


And remember use LIKE phrases only when necessary because they will degrade performance compared to other types of searches.

What is default list styling (CSS)?

You're resetting the margin on all elements in the second css block. Default margin is 40px - this should solve the problem:

.my_container ul {list-style:disc outside none; margin-left:40px;}

How to position a table at the center of div horizontally & vertically

To position horizontally center you can say width: 50%; margin: auto;. As far as I know, that's cross browser. For vertical alignment you can try vertical-align:middle;, but it may only work in relation to text. It's worth a try though.

How to create Password Field in Model Django

See my code which may help you. models.py

from django.db import models

class Customer(models.Model):
    name = models.CharField(max_length=100)
    email = models.EmailField(max_length=100)
    password = models.CharField(max_length=100)
    instrument_purchase = models.CharField(max_length=100)
    house_no = models.CharField(max_length=100)
    address_line1 = models.CharField(max_length=100)
    address_line2 = models.CharField(max_length=100)
    telephone = models.CharField(max_length=100)
    zip_code = models.CharField(max_length=20)
    state = models.CharField(max_length=100)
    country = models.CharField(max_length=100)

    def __str__(self):
        return self.name

forms.py

from django import forms
from models import *

class CustomerForm(forms.ModelForm):
    password = forms.CharField(widget=forms.PasswordInput)

    class Meta:
        model = Customer
        fields = ('name', 'email', 'password', 'instrument_purchase', 'house_no', 'address_line1', 'address_line2', 'telephone', 'zip_code', 'state', 'country')

How can I change cols of textarea in twitter-bootstrap?

UPDATE: As of Bootstrap 3.0, the input-* classes described below for setting the width of input elements were removed. Instead use the col-* classes to set the width of input elements. Examples are provided in the documentation.


In Bootstrap 2.3, you'd use the input classes for setting the width.

<textarea class="input-mini"></textarea>
<textarea class="input-small"></textarea>
<textarea class="input-medium"></textarea>
<textarea class="input-large"></textarea>
<textarea class="input-xlarge"></textarea>
<textarea class="input-xxlarge"></textarea>?
<textarea class="input-block-level"></textarea>?

Do a find for "Control sizing" for examples in the documentation.

But for height I think you'd still use the rows attribute.

Auto-scaling input[type=text] to width of value?

Input elements do behave differently from other elements, which would do just about what you want if you give them float: left (see http://jsfiddle.net/hEvYj/5/). I do not think that is possible without calculating it in some way with JavaScript (i.e. add 5px to the width per letter in the box).

How to avoid "RuntimeError: dictionary changed size during iteration" error?

I would try to avoid inserting empty lists in the first place, but, would generally use:

d = {k: v for k,v in d.iteritems() if v} # re-bind to non-empty

If prior to 2.7:

d = dict( (k, v) for k,v in d.iteritems() if v )

or just:

empty_key_vals = list(k for k in k,v in d.iteritems() if v)
for k in empty_key_vals:
    del[k]

Is there a sleep function in JavaScript?

function sleep(delay) {
    var start = new Date().getTime();
    while (new Date().getTime() < start + delay);
}

This code blocks for the specified duration. This is CPU hogging code. This is different from a thread blocking itself and releasing CPU cycles to be utilized by another thread. No such thing is going on here. Do not use this code, it's a very bad idea.

How can I add a column that doesn't allow nulls in a Postgresql database?

Specifying a default value would also work, assuming a default value is appropriate.

Passing an array as a function parameter in JavaScript

As @KaptajnKold had answered

var x = [ 'p0', 'p1', 'p2' ];
call_me.apply(this, x);

And you don't need to define every parameters for call_me function either. You can just use arguments

function call_me () {
    // arguments is a array consisting of params.
    // arguments[0] == 'p0',
    // arguments[1] == 'p1',
    // arguments[2] == 'p2'
}

Convert float64 column to int64 in Pandas

consider using

df['column name'].astype('Int64')

nan will be changed to NaN

Detect whether there is an Internet connection available on Android

The getActiveNetworkInfo() method of ConnectivityManager returns a NetworkInfo instance representing the first connected network interface it can find or null if none if the interfaces are connected. Checking if this method returns null should be enough to tell if an internet connection is available.

private boolean isNetworkAvailable() {
     ConnectivityManager connectivityManager = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
     NetworkInfo activeNetworkInfo = connectivityManager.getActiveNetworkInfo();
     return activeNetworkInfo != null; 
}

You will also need:

in your android manifest.

Edit:

Note that having an active network interface doesn't guarantee that a particular networked service is available. Networks issues, server downtime, low signal, captive portals, content filters and the like can all prevent your app from reaching a server. For instance you can't tell for sure if your app can reach Twitter until you receive a valid response from the Twitter service.

getActiveNetworkInfo() shouldn't never give null. I don't know what they were thinking when they came up with that. It should give you an object always.

Referenced Project gets "lost" at Compile Time

Check your build types of each project under project properties - I bet one or the other will be set to build against .NET XX - Client Profile.

With inconsistent versions, specifically with one being Client Profile and the other not, then it works at design time but fails at compile time. A real gotcha.

There is something funny going on in Visual Studio 2010 for me, which keeps setting projects seemingly randomly to Client Profile, sometimes when I create a project, and sometimes a few days later. Probably some keyboard shortcut I'm accidentally hitting...

AngularJS: How to make angular load script inside ng-include?

To dynamically load recaptcha from a ui-view I use the following method:

In application.js:

    .directive('script', function($parse, $rootScope, $compile) {
    return {
        restrict: 'E',
        terminal: true,
        link: function(scope, element, attr) {
            if (attr.ngSrc) {
                 var domElem = '<script src="'+attr.ngSrc+'" async defer></script>';
                 $(element).append($compile(domElem)(scope));


            }
        }
    };
});

In myPartial.client.view.html:

 <script type="application/javascript" ng-src="http://www.google.com/recaptcha/api.js?render=explicit&onload=vcRecaptchaApiLoaded"></script>

Getting Git to work with a proxy server - fails with "Request timed out"

I have tried all the above answers and nothing worked for me, as there was a proxy password encoding issues.

This command worked:

git config --global http.proxy http://[email protected]:PortNumber 

Do not enter the password in your command. It will dynamically ask for when you try to connect to any git repo.

PHP json_decode() returns NULL with valid JSON?

Maybe some hidden characters are messing with your json, try this:

$json = utf8_encode($yourString);
$data = json_decode($json);

Enum String Name from Value

Just cast the int to the enumeration type:

EnumDisplayStatus status = (EnumDisplayStatus) statusFromDatabase;
string statusString = status.ToString();

Reorder / reset auto increment primary key

You could drop the primary key column and re-create it. All the ids should then be reassigned in order.

However this is probably a bad idea in most situations. If you have other tables that have foreign keys to this table then it will definitely not work.

C# : 'is' keyword and checking for Not

Why not just use the else ?

if (child is IContainer)
{
  //
}
else
{
  // Do what you want here
}

Its neat it familiar and simple ?

Laravel: Validation unique on update

From Laravel 5.7, this works great

use Illuminate\Validation\Rule;

Validator::make($data, [
    'email' => [
        'required',
        Rule::unique('users')->ignore($user->id),
    ],
]);

Forcing A Unique Rule To Ignore A Given ID:

Fade In on Scroll Down, Fade Out on Scroll Up - based on element position in window

Sorry this is and old thread but some people would still need this I guess,

Note: I achieved this using Animate.css library for animating the fade.

I used your code and just added .hidden class (using bootstrap's hidden class) but you can still just define .hidden { opacity: 0; }

$(document).ready(function() {

/* Every time the window is scrolled ... */

$(window).scroll( function(){

/* Check the location of each desired element */
$('.hideme').each( function(i){

    var bottom_of_object = $(this).position().top + $(this).outerHeight();
    var bottom_of_window = $(window).scrollTop() + $(window).height();


    /* If the object is completely visible in the window, fade it it */
    if( bottom_of_window > bottom_of_object ){

        $(this).removeClass('hidden');
        $(this).addClass('animated fadeInUp');
    }    else {
            $(this).addClass('hidden');
               }

}); 
}); 
});

Another Note: Applying this to containers might cause it to be glitchy.

What is your single most favorite command-line trick using Bash?

Someone else recommended "M-x shell RET" in Emacs. I think "M-x eshell RET" is even better.

slf4j: how to log formatted message, object array, exception

As of SLF4J 1.6.0, in the presence of multiple parameters and if the last argument in a logging statement is an exception, then SLF4J will presume that the user wants the last argument to be treated as an exception and not a simple parameter. See also the relevant FAQ entry.

So, writing (in SLF4J version 1.7.x and later)

 logger.error("one two three: {} {} {}", "a", "b", 
              "c", new Exception("something went wrong"));

or writing (in SLF4J version 1.6.x)

 logger.error("one two three: {} {} {}", new Object[] {"a", "b", 
              "c", new Exception("something went wrong")});

will yield

one two three: a b c
java.lang.Exception: something went wrong
    at Example.main(Example.java:13)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at ...

The exact output will depend on the underlying framework (e.g. logback, log4j, etc) as well on how the underlying framework is configured. However, if the last parameter is an exception it will be interpreted as such regardless of the underlying framework.

Convert Long into Integer

If you are using Java 8 Do it as below

    import static java.lang.Math.toIntExact;

    public class DateFormatSampleCode {
        public static void main(String[] args) {
            long longValue = 1223321L;
            int longTointValue = toIntExact(longValue);
            System.out.println(longTointValue);

        }
}

Adding link a href to an element using css

You don't need CSS for this.

     <img src="abc"/>

now with link:

     <a href="#myLink"><img src="abc"/></a>

Or with jquery, later on, you can use the wrap property, see these questions answer:

how to add a link to an image using jquery?

Fast check for NaN in NumPy

If you're comfortable with it allows to create a fast short-circuit (stops as soon as a NaN is found) function:

import numba as nb
import math

@nb.njit
def anynan(array):
    array = array.ravel()
    for i in range(array.size):
        if math.isnan(array[i]):
            return True
    return False

If there is no NaN the function might actually be slower than np.min, I think that's because np.min uses multiprocessing for large arrays:

import numpy as np
array = np.random.random(2000000)

%timeit anynan(array)          # 100 loops, best of 3: 2.21 ms per loop
%timeit np.isnan(array.sum())  # 100 loops, best of 3: 4.45 ms per loop
%timeit np.isnan(array.min())  # 1000 loops, best of 3: 1.64 ms per loop

But in case there is a NaN in the array, especially if it's position is at low indices, then it's much faster:

array = np.random.random(2000000)
array[100] = np.nan

%timeit anynan(array)          # 1000000 loops, best of 3: 1.93 µs per loop
%timeit np.isnan(array.sum())  # 100 loops, best of 3: 4.57 ms per loop
%timeit np.isnan(array.min())  # 1000 loops, best of 3: 1.65 ms per loop

Similar results may be achieved with Cython or a C extension, these are a bit more complicated (or easily avaiable as bottleneck.anynan) but ultimatly do the same as my anynan function.

Missing Maven dependencies in Eclipse project

This same problem happened to me, and it was because there an error in downloading a jar due to repo issues, indicated by a red flag in the pom.xml.

I added another repository so the red flag in the pom.xml disappeared and Eclipse then loaded the pom again, resolved its issue and listed the maven dependencies in Project Explorer. it sounds simple and obvious to resolve visible issues, but since Eclipse was quite happy to run maven, and build successfully, it was not obvious that the red flag and repo issue were at the root of its unwillingness to parse the pom and list the maven dependencies

php delete a single file in directory

<?php 
    if(isset($_GET['delete'])){
        $delurl=$_GET['delete'];
        unlink($delurl);
    }
?>
<?php
if ($handle = opendir('.')) {
    while (false !== ($entry = readdir($handle))) {
        if ($entry != "." && $entry != "..") {
            echo "<a href=\"$entry\">$entry</a> | <a href=\"?delete=$entry\">Delete</a><br>";
        }
    }
    closedir($handle);
}
?>

This is It

What's the difference between integer class and numeric class in R

First off, it is perfectly feasible to use R successfully for years and not need to know the answer to this question. R handles the differences between the (usual) numerics and integers for you in the background.

> is.numeric(1)

[1] TRUE

> is.integer(1)

[1] FALSE

> is.numeric(1L)

[1] TRUE

> is.integer(1L)

[1] TRUE

(Putting capital 'L' after an integer forces it to be stored as an integer.)

As you can see "integer" is a subset of "numeric".

> .Machine$integer.max

[1] 2147483647

> .Machine$double.xmax

[1] 1.797693e+308

Integers only go to a little more than 2 billion, while the other numerics can be much bigger. They can be bigger because they are stored as double precision floating point numbers. This means that the number is stored in two pieces: the exponent (like 308 above, except in base 2 rather than base 10), and the "significand" (like 1.797693 above).

Note that 'is.integer' is not a test of whether you have a whole number, but a test of how the data are stored.

One thing to watch out for is that the colon operator, :, will return integers if the start and end points are whole numbers. For example, 1:5 creates an integer vector of numbers from 1 to 5. You don't need to append the letter L.

> class(1:5)
[1] "integer"

Reference: https://www.quora.com/What-is-the-difference-between-numeric-and-integer-in-R

Return a `struct` from a function in C

As far as I can remember, the first versions of C only allowed to return a value that could fit into a processor register, which means that you could only return a pointer to a struct. The same restriction applied to function arguments.

More recent versions allow to pass around larger data objects like structs. I think this feature was already common during the eighties or early nineties.

Arrays, however, can still be passed and returned only as pointers.

Python: How to get stdout after running os.system?

I had to use os.system, since subprocess was giving me a memory error for larger tasks. Reference for this problem here. So, in order to get the output of the os.system command I used this workaround:

import os

batcmd = 'dir'
result_code = os.system(batcmd + ' > output.txt')
if os.path.exists('output.txt'):
    fp = open('output.txt', "r")
    output = fp.read()
    fp.close()
    os.remove('output.txt')
    print(output)

How do I create a file at a specific path?

where is the file created?

In the application's current working directory. You can use os.getcwd to check it, and os.chdir to change it.

Opening file in the root directory probably fails due to lack of privileges.

What is size_t in C?

To go into why size_t needed to exist and how we got here:

In pragmatic terms, size_t and ptrdiff_t are guaranteed to be 64 bits wide on a 64-bit implementation, 32 bits wide on a 32-bit implementation, and so on. They could not force any existing type to mean that, on every compiler, without breaking legacy code.

A size_t or ptrdiff_t is not necessarily the same as an intptr_t or uintptr_t. They were different on certain architectures that were still in use when size_t and ptrdiff_t were added to the Standard in the late ’80s, and becoming obsolete when C99 added many new types but not gone yet (such as 16-bit Windows). The x86 in 16-bit protected mode had a segmented memory where the largest possible array or structure could be only 65,536 bytes in size, but a far pointer needed to be 32 bits wide, wider than the registers. On those, intptr_t would have been 32 bits wide but size_t and ptrdiff_t could be 16 bits wide and fit in a register. And who knew what kind of operating system might be written in the future? In theory, the i386 architecture offers a 32-bit segmentation model with 48-bit pointers that no operating system has ever actually used.

The type of a memory offset could not be long because far too much legacy code assumes that long is exactly 32 bits wide. This assumption was even built into the UNIX and Windows APIs. Unfortunately, a lot of other legacy code also assumed that a long is wide enough to hold a pointer, a file offset, the number of seconds that have elapsed since 1970, and so on. POSIX now provides a standardized way to force the latter assumption to be true instead of the former, but neither is a portable assumption to make.

It couldn’t be int because only a tiny handful of compilers in the ’90s made int 64 bits wide. Then they really got weird by keeping long 32 bits wide. The next revision of the Standard declared it illegal for int to be wider than long, but int is still 32 bits wide on most 64-bit systems.

It couldn’t be long long int, which anyway was added later, since that was created to be at least 64 bits wide even on 32-bit systems.

So, a new type was needed. Even if it weren’t, all those other types meant something other than an offset within an array or object. And if there was one lesson from the fiasco of 32-to-64-bit migration, it was to be specific about what properties a type needed to have, and not use one that meant different things in different programs.

Fade Effect on Link Hover?

You can do this with JQueryUI:

$('a').mouseenter(function(){
  $(this).animate({
    color: '#ff0000'
  }, 1000);
}).mouseout(function(){
  $(this).animate({
    color: '#000000'
  }, 1000);
});

http://jsfiddle.net/dWCbk/

Show hide divs on click in HTML and CSS without jQuery

You can use a checkbox to simulate onClick with CSS:

input[type=checkbox]:checked + p {
    display: none;
}

JSFiddle

Adjacent sibling selectors

font awesome icon in select option

I used this solution and it worked with Font Awesome 5: https://stackoverflow.com/a/50973559/3813846

What made the difference in my case was to add font-weight: 900;to the class. Keep in mind to 'fa' to the value.

Example of my code:

<select class="text-primary fa-select" name="class_logo" required>
  <option value="fa address-book">&#xf2b9; address-book</option>
  <option value="fa adjust">&#xf042; adjust</option>
  <option value="fa air-freshener">&#xf5d0; air-freshener</option>
</select>

CSS:

.fa-select {
    font-family: 'Lato', 'Font Awesome 5 Free';
    font-weight: 900;
}

Edit: If you are mixing Solid Icons with Brand Icons in the select, change the CSS as follows:

.fa-select {
    font-family: 'Lato', 'Font Awesome 5 Free', 'Font Awesome 5 Brands';
    font-weight: 900;
}

CakePHP find method with JOIN

Otro example, custom Data Pagination for JOIN

CODE in Controller CakePHP 2.6 is OK:

$this->SenasaPedidosFacturadosSds->recursive = -1;
    // Filtro
    $where = array(
        'joins' => array(
            array(
                'table' => 'usuarios',
                'alias' => 'Usuarios',
                'type' => 'INNER',
                'conditions' => array(
                    'Usuarios.usuario_id = SenasaPedidosFacturadosSds.usuarios_id'
                )
            ),
            array(
                'table' => 'senasa_pedidos',
                'alias' => 'SenasaPedidos',
                'type' => 'INNER',
                'conditions' => array(
                    'SenasaPedidos.id = SenasaPedidosFacturadosSds.senasa_pedidos_id'
                )
            ),
            array(
                'table' => 'clientes',
                'alias' => 'Clientes',
                'type' => 'INNER',
                'conditions' => array(
                    'Clientes.id_cliente = SenasaPedidos.clientes_id'
                )
            ),
        ),
        'fields'=>array(
            'SenasaPedidosFacturadosSds.*',
            'Usuarios.usuario_id',
            'Usuarios.apellido_nombre',
            'Usuarios.senasa_establecimientos_id',
            'Clientes.id_cliente',
            'Clientes.consolida_doc_sanitaria',
            'Clientes.requiere_senasa',
            'Clientes.razon_social',
            'SenasaPedidos.id',
            'SenasaPedidos.domicilio_entrega',
            'SenasaPedidos.sds',
            'SenasaPedidos.pt_ptr'
        ),
        'conditions'=>array(
            'Clientes.requiere_senasa'=>1
        ),
        'order' => 'SenasaPedidosFacturadosSds.created DESC',
        'limit'=>100
    );
    $this->paginate = $where;
    // Get datos
    $data = $this->Paginator->paginate();
    exit(debug($data));

OR Example 2, NOT active conditions:

$this->SenasaPedidosFacturadosSds->recursive = -1;
    // Filtro
    $where = array(
        'joins' => array(
            array(
                'table' => 'usuarios',
                'alias' => 'Usuarios',
                'type' => 'INNER',
                'conditions' => array(
                    'Usuarios.usuario_id = SenasaPedidosFacturadosSds.usuarios_id'
                )
            ),
            array(
                'table' => 'senasa_pedidos',
                'alias' => 'SenasaPedidos',
                'type' => 'INNER',
                'conditions' => array(
                    'SenasaPedidos.id = SenasaPedidosFacturadosSds.senasa_pedidos_id'
                )
            ),
            array(
                'table' => 'clientes',
                'alias' => 'Clientes',
                'type' => 'INNER',
                'conditions' => array(
                    'Clientes.id_cliente = SenasaPedidos.clientes_id',
                    'Clientes.requiere_senasa = 1'
                )
            ),
        ),
        'fields'=>array(
            'SenasaPedidosFacturadosSds.*',
            'Usuarios.usuario_id',
            'Usuarios.apellido_nombre',
            'Usuarios.senasa_establecimientos_id',
            'Clientes.id_cliente',
            'Clientes.consolida_doc_sanitaria',
            'Clientes.requiere_senasa',
            'Clientes.razon_social',
            'SenasaPedidos.id',
            'SenasaPedidos.domicilio_entrega',
            'SenasaPedidos.sds',
            'SenasaPedidos.pt_ptr'
        ),
        //'conditions'=>array(
        //    'Clientes.requiere_senasa'=>1
        //),
        'order' => 'SenasaPedidosFacturadosSds.created DESC',
        'limit'=>100
    );
    $this->paginate = $where;
    // Get datos
    $data = $this->Paginator->paginate();
    exit(debug($data));

I am getting Failed to load resource: net::ERR_BLOCKED_BY_CLIENT with Google chrome

You can also just run chrome in incognito mode, that automatically switches off all your plugins/extensions, including any add blockers. Then you can quickly see if the extensions are causing the problem.

matplotlib colorbar in each subplot

This can be easily solved with the the utility make_axes_locatable. I provide a minimal example that shows how this works and should be readily adaptable:

bar to each image

import matplotlib.pyplot as plt
from mpl_toolkits.axes_grid1 import make_axes_locatable

import numpy as np

m1 = np.random.rand(3, 3)
m2 = np.arange(0, 3*3, 1).reshape((3, 3))

fig = plt.figure(figsize=(16, 12))
ax1 = fig.add_subplot(121)
im1 = ax1.imshow(m1, interpolation='None')

divider = make_axes_locatable(ax1)
cax = divider.append_axes('right', size='5%', pad=0.05)
fig.colorbar(im1, cax=cax, orientation='vertical')

ax2 = fig.add_subplot(122)
im2 = ax2.imshow(m2, interpolation='None')

divider = make_axes_locatable(ax2)
cax = divider.append_axes('right', size='5%', pad=0.05)
fig.colorbar(im2, cax=cax, orientation='vertical');

Script for rebuilding and reindexing the fragmented index?

I have found the following script is very good at maintaining indexes, you can have this scheduled to run nightly or whatever other timeframe you wish.

http://sqlfool.com/2011/06/index-defrag-script-v4-1/

jQuery: get parent tr for selected radio button

Try this.

You don't need to prefix attribute name by @ in jQuery selector. Use closest() method to get the closest parent element matching the selector.

$("#MwDataList input[name=selectRadioGroup]:checked").closest('tr');

You can simplify your method like this

function getSelectedRowGuid() {
    return GetRowGuid(
      $("#MwDataList > input:radio[@name=selectRadioGroup]:checked :parent tr"));
}

closest() - Gets the first element that matches the selector, beginning at the current element and progressing up through the DOM tree.

As a side note, the ids of the elements should be unique on the page so try to avoid having same ids for radio buttons which I can see in your markup. If you are not going to use the ids then just remove it from the markup.

'0000-00-00 00:00:00' can not be represented as java.sql.Timestamp error

Whether or not the "date" '0000-00-00" is a valid "date" is irrelevant to the question. "Just change the database" is seldom a viable solution.

Facts:

  • MySQL allows a date with the value of zeros.
  • This "feature" enjoys widespread use with other languages.

So, if I "just change the database", thousands of lines of PHP code will break.

Java programmers need to accept the MySQL zero-date and they need to put a zero date back into the database, when other languages rely on this "feature".

A programmer connecting to MySQL needs to handle null and 0000-00-00 as well as valid dates. Changing 0000-00-00 to null is not a viable option, because then you can no longer determine if the date was expected to be 0000-00-00 for writing back to the database.

For 0000-00-00, I suggest checking the date value as a string, then changing it to ("y",1), or ("yyyy-MM-dd",0001-01-01), or into any invalid MySQL date (less than year 1000, iirc). MySQL has another "feature": low dates are automatically converted to 0000-00-00.

I realize my suggestion is a kludge. But so is MySQL's date handling. And two kludges don't make it right. The fact of the matter is, many programmers will have to handle MySQL zero-dates forever.

Launching a website via windows commandline

IE has a setting, located in Tools / Internet options / Advanced / Browsing, called Reuse windows for launching shortcuts, which is checked by default. For IE versions that support tabbed browsing, this option is relevant only when tab browsing is turned off (in fact, IE9 Beta explicitly mentions this). However, since IE6 does not have tabbed browsing, this option does affect opening URLs through the shell (as in your example).

clear data inside text file in c++

As far as I am aware, simply opening the file in write mode without append mode will erase the contents of the file.

ofstream file("filename.txt"); // Without append
ofstream file("filename.txt", ios::app); // with append

The first one will place the position bit at the beginning erasing all contents while the second version will place the position bit at the end-of-file bit and write from there.

How to Copy Contents of One Canvas to Another Canvas Locally

@robert-hurst has a cleaner approach.

However, this solution may also be used, in places when you actually want to have a copy of Data Url after copying. For example, when you are building a website that uses lots of image/canvas operations.

    // select canvas elements
    var sourceCanvas = document.getElementById("some-unique-id");
    var destCanvas = document.getElementsByClassName("some-class-selector")[0];

    //copy canvas by DataUrl
    var sourceImageData = sourceCanvas.toDataURL("image/png");
    var destCanvasContext = destCanvas.getContext('2d');

    var destinationImage = new Image;
    destinationImage.onload = function(){
      destCanvasContext.drawImage(destinationImage,0,0);
    };
    destinationImage.src = sourceImageData;

How do I determine the size of my array in C?

The macro ARRAYELEMENTCOUNT(x) that everyone is making use of evaluates incorrectly. This, realistically, is just a sensitive matter, because you can't have expressions that result in an 'array' type.

/* Compile as: CL /P "macro.c" */
# define ARRAYELEMENTCOUNT(x) (sizeof (x) / sizeof (x[0]))

ARRAYELEMENTCOUNT(p + 1);

Actually evaluates as:

(sizeof (p + 1) / sizeof (p + 1[0]));

Whereas

/* Compile as: CL /P "macro.c" */
# define ARRAYELEMENTCOUNT(x) (sizeof (x) / sizeof (x)[0])

ARRAYELEMENTCOUNT(p + 1);

It correctly evaluates to:

(sizeof (p + 1) / sizeof (p + 1)[0]);

This really doesn't have a lot to do with the size of arrays explicitly. I've just noticed a lot of errors from not truly observing how the C preprocessor works. You always wrap the macro parameter, not an expression in might be involved in.


This is correct; my example was a bad one. But that's actually exactly what should happen. As I previously mentioned p + 1 will end up as a pointer type and invalidate the entire macro (just like if you attempted to use the macro in a function with a pointer parameter).

At the end of the day, in this particular instance, the fault doesn't really matter (so I'm just wasting everyone's time; huzzah!), because you don't have expressions with a type of 'array'. But really the point about preprocessor evaluation subtles I think is an important one.

SQL Add foreign key to existing column

Maybe you got your columns backwards??

ALTER TABLE Employees
ADD FOREIGN KEY (UserID)           <-- this needs to be a column of the Employees table
REFERENCES ActiveDirectories(id)   <-- this needs to be a column of the ActiveDirectories table

Could it be that the column is called ID in the Employees table, and UserID in the ActiveDirectories table?

Then your command should be:

ALTER TABLE Employees
ADD FOREIGN KEY (ID)                   <-- column in table "Employees"
REFERENCES ActiveDirectories(UserID)   <-- column in table "ActiveDirectories" 

Split array into two parts without for loop in java

copyOfRange

This does what you want without you having to create a new array as it returns a new array.

int[] original = new int[300000];
int[] firstHalf = Arrays.copyOfRange(original, 0, original.length/2);

What would be the Unicode character for big bullet in the middle of the character?

You can use a span with 50% border radius.

_x000D_
_x000D_
 .mydot{_x000D_
     background: rgb(66, 183, 42);_x000D_
     border-radius: 50%;_x000D_
     display: inline-block;_x000D_
     height: 20px;_x000D_
     margin-left: 4px;_x000D_
     margin-right: 4px;_x000D_
     width: 20px;_x000D_
}    
_x000D_
<span class="mydot"></span>
_x000D_
_x000D_
_x000D_

RegEx to parse or validate Base64 data

To validate base64 image we can use this regex

/^data:image/(?:gif|png|jpeg|bmp|webp)(?:;charset=utf-8)?;base64,(?:[A-Za-z0-9]|[+/])+={0,2}

  private validBase64Image(base64Image: string): boolean {
    const regex = /^data:image\/(?:gif|png|jpeg|bmp|webp)(?:;charset=utf-8)?;base64,(?:[A-Za-z0-9]|[+/])+={0,2}/;
    return base64Image && regex.test(base64Image);
  }

Format decimal for percentage values?

I have found the above answer to be the best solution, but I don't like the leading space before the percent sign. I have seen somewhat complicated solutions, but I just use this Replace addition to the answer above instead of using other rounding solutions.

String.Format("Value: {0:P2}.", 0.8526).Replace(" %","%") // formats as 85.26% (varies by culture)

Check whether IIS is installed or not?

I simple gave below in all my browsers. I got image IIS7

http://localhost/

How to make HTML code inactive with comments

Just create a multi-line comment around it. When you want it back, just erase the comment tags.

For example, <!-- Stuff to comment out or make inactive -->

Use find command but exclude files in two directories

Here's how you can specify that with find:

find . -type f -name "*_peaks.bed" ! -path "./tmp/*" ! -path "./scripts/*"

Explanation:

  • find . - Start find from current working directory (recursively by default)
  • -type f - Specify to find that you only want files in the results
  • -name "*_peaks.bed" - Look for files with the name ending in _peaks.bed
  • ! -path "./tmp/*" - Exclude all results whose path starts with ./tmp/
  • ! -path "./scripts/*" - Also exclude all results whose path starts with ./scripts/

Testing the Solution:

$ mkdir a b c d e
$ touch a/1 b/2 c/3 d/4 e/5 e/a e/b
$ find . -type f ! -path "./a/*" ! -path "./b/*"

./d/4
./c/3
./e/a
./e/b
./e/5

You were pretty close, the -name option only considers the basename, where as -path considers the entire path =)

How to position one element relative to another with jQuery?

Something like this?

$(menu).css("top", targetE1.y + "px"); 
$(menu).css("left", targetE1.x - widthOfMenu + "px");

how to prevent css inherit

Using the wildcard * selector in CSS to override inheritance for all attributes of an element (by setting these back to their initial state).

An example of its use:

li * {
   display: initial;
}

How to modify existing, unpushed commit messages?

If the commit you want to fix isn’t the most recent one:

  1. git rebase --interactive $parent_of_flawed_commit

    If you want to fix several flawed commits, pass the parent of the oldest one of them.

  2. An editor will come up, with a list of all commits since the one you gave.

    1. Change pick to reword (or on old versions of Git, to edit) in front of any commits you want to fix.
    2. Once you save, Git will replay the listed commits.

  3. For each commit you want to reword, Git will drop you back into your editor. For each commit you want to edit, Git drops you into the shell. If you’re in the shell:

    1. Change the commit in any way you like.
    2. git commit --amend
    3. git rebase --continue

Most of this sequence will be explained to you by the output of the various commands as you go. It’s very easy; you don’t need to memorise it – just remember that git rebase --interactive lets you correct commits no matter how long ago they were.


Note that you will not want to change commits that you have already pushed. Or maybe you do, but in that case you will have to take great care to communicate with everyone who may have pulled your commits and done work on top of them. How do I recover/resynchronise after someone pushes a rebase or a reset to a published branch?

How do I make a dictionary with multiple keys to one value?

It is simple. The first thing that you have to understand the design of the Python interpreter. It doesn't allocate memory for all the variables basically if any two or more variable has the same value it just map to that value.

let's go to the code example,

In [6]: a = 10

In [7]: id(a)
Out[7]: 10914656

In [8]: b = 10

In [9]: id(b)
Out[9]: 10914656

In [10]: c = 11

In [11]: id(c)
Out[11]: 10914688

In [12]: d = 21

In [13]: id(d)
Out[13]: 10915008

In [14]: e = 11

In [15]: id(e)
Out[15]: 10914688

In [16]: e = 21

In [17]: id(e)
Out[17]: 10915008

In [18]: e is d
Out[18]: True
In [19]: e = 30

In [20]: id(e)
Out[20]: 10915296

From the above output, variables a and b shares the same memory, c and d has different memory when I create a new variable e and store a value (11) which is already present in the variable c so it mapped to that memory location and doesn't create a new memory when I change the value present in the variable e to 21 which is already present in the variable d so now variables d and e share the same memory location. At last, I change the value in the variable e to 30 which is not stored in any other variable so it creates a new memory for e.

so any variable which is having same value shares the memory.

Not for list and dictionary objects

let's come to your question.

when multiple keys have same value then all shares same memory so the thing that you expect is already there in python.

you can simply use it like this

In [49]: dictionary = {
    ...:     'k1':1,
    ...:     'k2':1,
    ...:     'k3':2,
    ...:     'k4':2}
    ...:     
    ...:     

In [50]: id(dictionary['k1'])
Out[50]: 10914368

In [51]: id(dictionary['k2'])
Out[51]: 10914368

In [52]: id(dictionary['k3'])
Out[52]: 10914400

In [53]: id(dictionary['k4'])
Out[53]: 10914400

From the above output, the key k1 and k2 mapped to the same address which means value one stored only once in the memory which is multiple key single value dictionary this is the thing you want. :P

How to auto generate migrations with Sequelize CLI from Sequelize models?

It's 2020 and many of these answers no longer apply to the Sequelize v4/v5/v6 ecosystem.

The one good answer says to use sequelize-auto-migrations, but probably is not prescriptive enough to use in your project. So here's a bit more color...

Setup

My team uses a fork of sequelize-auto-migrations because the original repo is has not been merged a few critical PRs. #56 #57 #58 #59

$ yarn add github:scimonster/sequelize-auto-migrations#a063aa6535a3f580623581bf866cef2d609531ba

Edit package.json:

"scripts": {
  ...
  "db:makemigrations": "./node_modules/sequelize-auto-migrations/bin/makemigration.js",
  ...
}

Process

Note: Make sure you’re using git (or some source control) and database backups so that you can undo these changes if something goes really bad.

  1. Delete all old migrations if any exist.
  2. Turn off .sync()
  3. Create a mega-migration that migrates everything in your current models (yarn db:makemigrations --name "mega-migration").
  4. Commit your 01-mega-migration.js and the _current.json that is generated.
  5. if you've previously run .sync() or hand-written migrations, you need to “Fake” that mega-migration by inserting the name of it into your SequelizeMeta table. INSERT INTO SequelizeMeta Values ('01-mega-migration.js').
  6. Now you should be able to use this as normal…
  7. Make changes to your models (add/remove columns, change constraints)
  8. Run $ yarn db:makemigrations --name whatever
  9. Commit your 02-whatever.js migration and the changes to _current.json, and _current.bak.json.
  10. Run your migration through the normal sequelize-cli: $ yarn sequelize db:migrate.
  11. Repeat 7-10 as necessary

Known Gotchas

  1. Renaming a column will turn into a pair of removeColumn and addColumn. This will lose data in production. You will need to modify the up and down actions to use renameColumn instead.

For those who confused how to use renameColumn, the snippet would look like this. (switch "column_name_before" and "column_name_after" for the rollbackCommands)

{
    fn: "renameColumn",
    params: [
        "table_name",
        "column_name_before",
        "column_name_after",
        {
            transaction: transaction
        }
    ]
}
  1. If you have a lot of migrations, the down action may not perfectly remove items in an order consistent way.

  2. The maintainer of this library does not actively check it. So if it doesn't work for you out of the box, you will need to find a different community fork or another solution.

Convert array to JSON

If you have only 1 object like the one you asked, the following will work.

var x = [{'a':'b'}];
var b= JSON.stringify(x);
var c = b.substring(1,b.length-1);
JSON.parse(c); 

Displaying standard DataTables in MVC

Here is the answer in Razor syntax

 <table border="1" cellpadding="5">
    <thead>
       <tr>
          @foreach (System.Data.DataColumn col in Model.Columns)
          {
             <th>@col.Caption</th>
          }
       </tr>
    </thead>
    <tbody>
    @foreach(System.Data.DataRow row in Model.Rows)
    {
       <tr>
          @foreach (var cell in row.ItemArray)
          {
             <td>@cell.ToString()</td>
          }
       </tr>
    }      
    </tbody>
</table>

how to have two headings on the same line in html

You should only need to do one of:

  • Make them both inline (or inline-block)
  • Set them to float left or right

You should be able to adjust the height, padding, or margin properties of the smaller heading to compensate for its positioning. I recommend setting both headings to have the same height.

See this live jsFiddle for an example.

(code of the jsFiddle):

CSS

h2 {
  font-size: 50px;
}

h3 {
  font-size: 30px;
}

h2, h3 {
  width: 50%;
  height: 60px;
  margin: 0;
  padding: 0;
  display: inline;
}?

HTML

<h2>Big Heading</h2>
<h3>Small(er) Heading</h3>
<hr />?

What is the `data-target` attribute in Bootstrap 3?

data-target is used by bootstrap to make your life easier. You (mostly) do not need to write a single line of Javascript to use their pre-made JavaScript components.

The data-target attribute should contain a CSS selector that points to the HTML Element that will be changed.

Modal Example Code from BS3:

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

<!-- Modal -->
<div class="modal fade" id="myModal" tabindex="-1" role="dialog" aria-labelledby="myModalLabel" aria-hidden="true">
  [...]
</div>

In this example, the button has data-target="#myModal", if you click on it, <div id="myModal">...</div> will be modified (in this case faded in). This happens because #myModal in CSS selectors points to elements that have an id attribute with the myModal value.

Further information about the HTML5 "data-" attribute: https://developer.mozilla.org/en-US/docs/Web/Guide/HTML/Using_data_attributes

How can I add (simple) tracing in C#?

DotNetCoders has a starter article on it: http://www.dotnetcoders.com/web/Articles/ShowArticle.aspx?article=50. They talk about how to set up the switches in the configuration file and how to write the code, but it is pretty old (2002).

There's another article on CodeProject: A Treatise on Using Debug and Trace classes, including Exception Handling, but it's the same age.

CodeGuru has another article on custom TraceListeners: Implementing a Custom TraceListener

MySQL INSERT INTO ... VALUES and SELECT

Use an insert ... select query, and put the known values in the select:

insert into table1
select 'A string', 5, idTable2
from table2
where ...

Regex - Does not contain certain Characters

^[^<>]+$

The caret in the character class ([^) means match anything but, so this means, beginning of string, then one or more of anything except < and >, then the end of the string.