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How to fix error "ERROR: Command errored out with exit status 1: python." when trying to install django-heroku using pip

You need to add the package containing the executable pg_config.

A prior answer should have details you need: pg_config executable not found

What could cause an error related to npm not being able to find a file? No contents in my node_modules subfolder. Why is that?

I had the SAME issue today and it was driving me nuts!!! What I had done was upgrade to node 8.10 and upgrade my NPM to the latest I uninstalled angular CLI

npm uninstall -g angular-cli
npm uninstall --save-dev angular-cli

I then verified my Cache from NPM if it wasn't up to date I cleaned it and ran the install again if npm version is < 5 then use npm cache clean --force

npm install -g @angular/cli@latest

and created a new project file and create a new angular project.

Node.js: Python not found exception due to node-sass and node-gyp

I found the same issue with Node 12.19.0 and yarn 1.22.5 on Windows 10. I fixed the problem by installing latest stable python 64-bit with adding the path to Environment Variables during python installation. After python installation, I restarted my machine for env vars.

TypeError: expected str, bytes or os.PathLike object, not _io.BufferedReader

I think it has to do with your second element in storbinary. You are trying to open file, but it is already a pointer to the file you opened in line file = open(local_path,'rb'). So, try to use ftp.storbinary("STOR " + i, file).

How to solve npm error "npm ERR! code ELIFECYCLE"

Resolved like this:

# chown -R <user>: node_modules

Maximum call stack size exceeded on npm install

Following steps helped me to solve this issue:

  1. Stop all react strips (e.g. start build)
  2. run npm cache clean --force
  3. run npm install

Why does C++ code for testing the Collatz conjecture run faster than hand-written assembly?

Even without looking at assembly, the most obvious reason is that /= 2 is probably optimized as >>=1 and many processors have a very quick shift operation. But even if a processor doesn't have a shift operation, the integer division is faster than floating point division.

Edit: your milage may vary on the "integer division is faster than floating point division" statement above. The comments below reveal that the modern processors have prioritized optimizing fp division over integer division. So if someone were looking for the most likely reason for the speedup which this thread's question asks about, then compiler optimizing /=2 as >>=1 would be the best 1st place to look.


On an unrelated note, if n is odd, the expression n*3+1 will always be even. So there is no need to check. You can change that branch to

{
   n = (n*3+1) >> 1;
   count += 2;
}

So the whole statement would then be

if (n & 1)
{
    n = (n*3 + 1) >> 1;
    count += 2;
}
else
{
    n >>= 1;
    ++count;
}

How to install and run Typescript locally in npm?

You need to tell npm that "tsc" exists as a local project package (via the "scripts" property in your package.json) and then run it via npm run tsc. To do that (at least on Mac) I had to add the path for the actual compiler within the package, like this

{
  "name": "foo"
  "scripts": {
    "tsc": "./node_modules/typescript/bin/tsc"
  },
  "dependencies": {
    "typescript": "^2.3.3",
    "typings": "^2.1.1"
  }
}

After that you can run any TypeScript command like npm run tsc -- --init (the arguments come after the first --).

Add Favicon with React and Webpack

Use the file-loader for that:

{
    test: /\.(svg|png|gif|jpg|ico)$/,
    include: path.resolve(__dirname, path),
    use: {
        loader: 'file-loader',
        options: {
            context: 'src/assets',
            name: 'root[path][name].[ext]'
        }
    }
}

NPM stuck giving the same error EISDIR: Illegal operation on a directory, read at error (native)

Make sure node_modules (and your root package.json) doesn't contain a reference to npm's "package.json" module. Deleting package.json FOLDER from node_modules solved the issue for me.

Angular2 QuickStart npm start is not working correctly

This answer is for Windows 10 users only and as you'll see below, I suspect the problem is happening only for those users:

To find out what is happening, you can run the command on PowerShell and it will tell you what is the actual problem:

PS C:\Users\Laurent-Philippe> tsc && concurrently "tsc -w" "lite-server"
At line:1 char:5
+ tsc && concurrently "tsc -w" "lite-server"
+     ~~
The token '&&' is not a valid statement separator in this version.
    + CategoryInfo          : ParserError: (:) [], ParentContainsErrorRecordException
    + FullyQualifiedErrorId : InvalidEndOfLine

Basically, the message explains that the token "&&" is not yet valid with Windows 10. And for those wondering, the same command replacing && with &, informed us that the ampersand operator is reserved for future use:

 (&) character is not allowed. The & operator is reserved for future use; wrap an ampersand in double quotation marks ("&") to pass it as part of a string.

Conclusions:

  • if you want to manually launch this command from the powershell, you can use this instead:

    tsc "&" concurrently "tsc -w" "lite-server"

  • if you want to launch your application with npm start, replace the start line in your package.json by:

    "start": "tsc & concurrently \"tsc -w\" \"lite-server\" "

  • alternatively, the answer of user60108 also works because he is not using the ampersand:

    "start": "concurrently \"npm run tsc:w\" \"npm run lite\" "

Can't get private key with openssl (no start line:pem_lib.c:703:Expecting: ANY PRIVATE KEY)

On my execution of openssl pkcs12 -export -out cacert.pkcs12 -in testca/cacert.pem, I received the following message:

unable to load private key 140707250050712:error:0906D06C:PEM routines:PEM_read_bio:no start line:pem_lib.c:701:Expecting: ANY PRIVATE KEY`

Got this solved by providing the key file along with the command. The switch is -inkey inkeyfile.pem

"Please try running this command again as Root/Administrator" error when trying to install LESS

I also got the problem. This is what I did:

  1. Uninstalled nodeJs from Control Panel > Uninstall a program
  2. There are 2 folders in users//appData/roaming --> npm folder and npm-cache folder. Delete both of these.

Now, go to nodeJS site, and install again. Select 2nd option in installation option (ie npm package). Install it. You problem must be solved by now.

Can't install Scipy through pip

You can test this answer:

python -m pip install --user numpy scipy matplotlib ipython jupyter pandas sympy nose

Spring Boot and multiple external configuration files

A modified version of @mxsb solution that allows us to define multiple files and in my case these are yml files.

In my application-dev.yml, I added this config that allows me to inject all the yml that have -dev.yml in them. This can be a list of specific files also. "classpath:/test/test.yml,classpath:/test2/test.yml"

application:
  properties:
    locations: "classpath*:/**/*-dev.yml"

This helps to get a properties map.

@Configuration

public class PropertiesConfig {

private final static Logger LOG = LoggerFactory.getLogger(PropertiesConfig.class);

@Value("${application.properties.locations}")
private String[] locations;

@Autowired
private ResourceLoader rl;

@Bean
Map<String, Properties> myProperties() {
    return stream(locations)
            .collect(toMap(filename -> filename, this::loadProperties));
}

private Properties loadProperties(final String filename) {

    YamlPropertySourceLoader loader = new YamlPropertySourceLoader();
    try {
        final Resource[] possiblePropertiesResources = ResourcePatternUtils.getResourcePatternResolver(rl).getResources(filename);
        final Properties properties = new Properties();
        stream(possiblePropertiesResources)
                .filter(Resource::exists)
                .map(resource1 -> {
                    try {
                        return loader.load(resource1.getFilename(), resource1);
                    } catch (IOException e) {
                        throw new RuntimeException(e);
                    }
                }).flatMap(l -> l.stream())
                .forEach(propertySource -> {
                    Map source = ((MapPropertySource) propertySource).getSource();
                    properties.putAll(source);
                });

        return properties;
    } catch (IOException e) {
        throw new RuntimeException(e);
    }
}
}

However, if like in my case, I wanted to have to split yml files for each profile and load them and inject that directly into spring configuration before beans initialisation.

config
    - application.yml
    - application-dev.yml
    - application-prod.yml
management
    - management-dev.yml
    - management-prod.yml

... you get the idea

The component is slightly different

@Component
public class PropertiesConfigurer extends     PropertySourcesPlaceholderConfigurer
    implements EnvironmentAware, InitializingBean {

private final static Logger LOG = LoggerFactory.getLogger(PropertiesConfigurer.class);

private String[] locations;

@Autowired
private ResourceLoader rl;
private Environment environment;

@Override
public void setEnvironment(Environment environment) {
    // save off Environment for later use
    this.environment = environment;
    super.setEnvironment(environment);
}

@Override
public void afterPropertiesSet() throws Exception {
    // Copy property sources to Environment
    MutablePropertySources envPropSources = ((ConfigurableEnvironment) environment).getPropertySources();
    envPropSources.forEach(propertySource -> {
        if (propertySource.containsProperty("application.properties.locations")) {
            locations = ((String) propertySource.getProperty("application.properties.locations")).split(",");
            stream(locations).forEach(filename -> loadProperties(filename).forEach(source ->{
                envPropSources.addFirst(source);
            }));
        }
    });
}


private List<PropertySource> loadProperties(final String filename) {
    YamlPropertySourceLoader loader = new YamlPropertySourceLoader();
    try {
        final Resource[] possiblePropertiesResources = ResourcePatternUtils.getResourcePatternResolver(rl).getResources(filename);
        final Properties properties = new Properties();
        return stream(possiblePropertiesResources)
                .filter(Resource::exists)
                .map(resource1 -> {
                    try {
                        return loader.load(resource1.getFilename(), resource1);
                    } catch (IOException e) {
                        throw new RuntimeException(e);
                    }
                }).flatMap(l -> l.stream())
                .collect(Collectors.toList());
    } catch (IOException e) {
        throw new RuntimeException(e);
    }
}

}

Filezilla FTP Server Fails to Retrieve Directory Listing

It worked for me:

General -> Encryption -> Only use plain FTP

Transfer settings -> Transfer Mode -> Active

Consider that it is very insecure, and must be used only for testing.

npm install error from the terminal

Running just "npm install" will look for dependencies listed in your package.json. The error you're getting says that you don't have a package.json file set up (or you're in the wrong directory).

If you're trying to install a specific package, you should use 'npm install {package name}'. See here for more info about the command.

Otherwise, you'll need to create a package.json file for your dependencies or go to the right directory and then run 'npm install'.

Npm Please try using this command again as root/administrator

On windows 10, npm cache clean --force and npm cache verify did not work for me. Tried to delete cache folder and file with administrator permission, did not work. The process-explorer tool helped me finding that Node.exe is holding on the cache file. I killed the process and tried to clean, worked.

Failed to install Python Cryptography package with PIP and setup.py

If you are building a python package distribution in a .gitlab-ci.yml file in for GitLab CI that uses a gitlab runner deployed in an AWS EC2 machine

 - apk add --update alpine-sdk && \
 - apk add libffi-dev openssl-dev && \
 - apk --no-cache --update add build-base

SSL Error: CERT_UNTRUSTED while using npm command

I think I got the reason for the above error. It is the corporate proxy(virtual private network) provided in order to work in the client network. Without that connection I frequently faced the same problem be it maven build or npm install.

json: cannot unmarshal object into Go value of type

Here's a fixed version of it: http://play.golang.org/p/w2ZcOzGHKR

The biggest fix that was needed is when Unmarshalling an array, that property needs to be an array/slice in the struct as well.

For example:

{ "things": ["a", "b", "c"] }

Would Unmarshal into a:

type Item struct {
    Things []string
}

And not into:

type Item struct {
    Things string
}

The other thing to watch out for when Unmarshaling is that the types line up exactly. It will fail when Unmarshalling a JSON string representation of a number into an int or float field -- "1" needs to Unmarshal into a string, not into an int like we saw with ShippingAdditionalCost int

Subprocess changing directory

Another option based on this answer: https://stackoverflow.com/a/29269316/451710

This allows you to execute multiple commands (e.g cd) in the same process.

import subprocess

commands = '''
pwd
cd some-directory
pwd
cd another-directory
pwd
'''

process = subprocess.Popen('/bin/bash', stdin=subprocess.PIPE, stdout=subprocess.PIPE)
out, err = process.communicate(commands.encode('utf-8'))
print(out.decode('utf-8'))

NodeJS - Error installing with NPM

For windows

Check python path in system variable. npm plugins need node-gyp to be installed.

open command prompt with admin rights, and run following command.

npm install --global --production windows-build-tools

npm install --global node-gyp

npm not working after clearing cache

Try npm cache clean --force if it doesn't work then manually delete %appdata%\npm-cache folder.

and install npm install npm@latest -g

It worked for me.

visit this link

How to approach a "Got minus one from a read call" error when connecting to an Amazon RDS Oracle instance

I would like to augment to Stephen C's answer, my case was on the first dot. So since we have DHCP to allocate IP addresses in the company, DHCP changed my machine's address without of course asking neither me nor Oracle. So out of the blue oracle refused to do anything and gave the minus one dreaded exception. So if you want to workaround this once and for ever, and since TCP.INVITED_NODES of SQLNET.ora file does not accept wildcards as stated here, you can add you machine's hostname instead of the IP address.

npm not working - "read ECONNRESET"

The three thing to make npm working well inside the proxy network .

This set npm registry , By default it may take https.

npm config set registry "http://registry.npmjs.org/"

Second is two set proxy in your system . If your organization use proxy or you.

npm config set proxy "http://username:password@proxy-url:proxy-port"

npm config set https-proxy "http://username:password@proxy-url:proxy-port"

You can also check if they are set or not , by

npm config get https-proxy

for all values.

"Couldn't read dependencies" error with npm

I had an "Invalid Name"

I switched from "name": "Some Name",... to "name": "Some-Name",...

Guess name needs to be a sluggy string.

npm install errors with Error: ENOENT, chmod

This problem somehow arose for me on Mac when I was trying to run npm install -g bower. It was giving me a number of errors for not being able to find things like graceful-fs. I'm not sure how I installed npm originally, but it looks like perhaps it came down with node using homebrew. I first ran

brew uninstall node

This removed both node and npm from my path. From there I just reinstalled it

brew install node

When it completed I had node and npm on my path and I was able to run

rm -rf ~/.npm
npm install -g bower

This then installed bower successfully.

Updating the brew formulas and upgrading the installs didn't seem to work for me, I'm not sure why. The removal of the .npm folder was something that had worked for other people, and I had tried it without success. I did it this time just in case. Note also that neither of the following solved the problem for me, although it did for others:

npm cache clean
sudo npm cache clean

Can't install via pip because of egg_info error

Found out what was wrong. I never installed the setuptools for python, so it was missing some vital files, like the egg ones.

If you find yourself having my issue above, download this file and then in powershell or command prompt, navigate to ez_setup’s directory and execute the command and this will run the file for you:

$ [sudo] python ez_setup.py

If you still need to install pip at this point, run:

$ [sudo] easy_install pip

easy_install was part of the setuptools, and therefore wouldn't work for installing pip.

Then, pip will successfully install django with the command:

$ [sudo] pip install django

Hope I saved someone the headache I gave myself!

~Zorpix

How to install an npm package from GitHub directly?

Install it directly:

npm install visionmedia/express

Alternatively, you can add "express": "github:visionmedia/express" to the "dependencies" section of package.json file, then run:

npm install

How to get the current working directory using python 3?

It seems that IDLE changes its current working dir to location of the script that is executed, while when running the script using cmd doesn't do that and it leaves CWD as it is.

To change current working dir to the one containing your script you can use:

import os
os.chdir(os.path.dirname(__file__))
print(os.getcwd())

The __file__ variable is available only if you execute script from file, and it contains path to the file. More on it here: Python __file__ attribute absolute or relative?

Can't install any package with node npm

For future reference, this can also happen if npm is down. That's how I found this question. Wish the first npm task was a server status check so there was a clearer error message.

npm throws error without sudo

As if we need more answers here, but anyway..

Sindre Sorus has a guide Install npm packages globally without sudo on OS X and Linux outlining how to cleanly install without messing with permissions:

Here is a way to install packages globally for a given user.

  1. Create a directory for your global packages

    mkdir "${HOME}/.npm-packages"
    
  2. Reference this directory for future usage in your .bashrc/.zshrc:

    NPM_PACKAGES="${HOME}/.npm-packages"
    
  3. Indicate to npm where to store your globally installed package. In your $HOME/.npmrc file add:

    prefix=${HOME}/.npm-packages
    
  4. Ensure node will find them. Add the following to your .bashrc/.zshrc:

    NODE_PATH="$NPM_PACKAGES/lib/node_modules:$NODE_PATH"
    
  5. Ensure you'll find installed binaries and man pages. Add the following to your .bashrc/.zshrc:

    PATH="$NPM_PACKAGES/bin:$PATH"
    # Unset manpath so we can inherit from /etc/manpath via the `manpath`
    # command
    unset MANPATH # delete if you already modified MANPATH elsewhere in your config
    MANPATH="$NPM_PACKAGES/share/man:$(manpath)"
    

Check out npm-g_nosudo for doing the above steps automagically

Checkout the source of this guide for the latest updates.

nodejs npm global config missing on windows

Have you tried running npm config list? And, if you want to see the defaults, run npm config ls -l.

PHP CURL CURLOPT_SSL_VERIFYPEER ignored

According to documentation: to verify host or peer certificate you need to specify alternate certificates with the CURLOPT_CAINFO option or a certificate directory can be specified with the CURLOPT_CAPATH option.

Also look at CURLOPT_SSL_VERIFYHOST:

  • 1 to check the existence of a common name in the SSL peer certificate.
  • 2 to check the existence of a common name and also verify that it matches the hostname provided.

curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, 0);
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, 0);

Running Python on Windows for Node.js dependencies

Your problem is that you didn't set the environment variable.

The error clearly says this:

gyp ERR! stack Error: Can't find Python executable "python", you can set the PYTHON env variable.

And in your comment, you say you did this:

set PYTHONPATH=%PYTHONPATH%;C:\My_python_lib

That's nice, but that doesn't set the PYTHON variable, it sets the PYTHONPATH variable.


Meanwhile, just using the set command only affects the current cmd session. If you reboot after that, as you say you did, you end up with a whole new cmd session that doesn't have that variable set in it.

There are a few ways to set environment variables permanently—the easiest is in the System Control Panel in XP, which is of course different in Vista, different again in 7, and different again in 8, but you can google for it.

Alternatively, just do the set right before the npm command, without rebooting in between.


You can test whether you've done things right by doing the exact same thing the config script is trying to do: Before running npm, try running %PYTHON%. If you've done it right, you'll get a Python interpreter (which you can immediately quit). If you get an error, you haven't done it right.


There are two problems with this:

set PYTHON=%PYTHON%;D:\Python

First, you're setting PYTHON to ;D:\Python. That extra semicolon is fine for a semicolon-separated list of paths, like PATH or PYTHONPATH, but not for a single value like PYTHON. And likewise, adding a new value to the existing value is what you want when you want to add another path to a list of paths, but not for a single value. So, you just want set PYTHON=D:\Python.

Second, D:\Python is not the path to your Python interpreter. It's something like D:\Python\Python.exe, or D:\Python\bin\Python.exe. Find the right path, make sure it works on its own (e.g., type D:\Python\bin\Python.exe and make sure you get a Python interpreter), then set the variable and use it.


So:

set PYTHON=D:\Python\bin\Python.exe

Or, if you want to make it permanent, do the equivalent in the Control Panel.

Cannot install node modules that require compilation on Windows 7 x64/VS2012

After DAYS of digging, someone on IRC suggested that I try to use the

Windows 7.1 SDK Command Prompt

Shortcut (links to C:\Windows\System32\cmd.exe /E:ON /V:ON /T:0E /K "C:\Program Files\Microsoft SDKs\Windows\v7.1\Bin\SetEnv.cmd"). I think you MUST have the older 7.1 SDK (even on Windows 8.1) because the newer ones use msbuild.exe instead of vcbuild.exe which is what node-gyp wants even though it's twice as old as node at this point :/

Once in that prompt, I had to run the following to get x86 context because the compiler was throwing as error otherwise about architecture:

setenv.cmd /Release /x86

THEN I was able to successfully run npm commands that were trying to use node-gyp to recompile things.

Error: Segmentation fault (core dumped)

There is one more reason for such failure which I came to know when mine failed

  • You might be working with a lot of data and your RAM is full

This might not apply in this case but it also throws the same error and since this question comes up on top for this error, I have added this answer here.

Save current directory in variable using Bash?

One more variant:

export PATH=$PATH:\`pwd`:/foo/bar

How to read a file in other directory in python

You can't "open" a directory using the open function. This function is meant to be used to open files.

Here, what you want to do is open the file that's in the directory. The first thing you must do is compute this file's path. The os.path.join function will let you do that by joining parts of the path (the directory and the file name):

fpath = os.path.join(direct, "5_1.txt")

You can then open the file:

f = open(fpath)

And read its content:

content = f.read()

Additionally, I believe that on Windows, using open on a directory does return a PermissionDenied exception, although that's not really the case.

"message failed to fetch from registry" while trying to install any module

for raspberry pi I found and modified a solution I found
here is what I ran

sudo su -
cd /opt
wget http://nodejs.org/dist/v0.10.28/node-v0.10.28-linux-arm-pi.tar.gz
tar xvzf node-v0.10.28-linux-arm-pi.tar.gz
ln -s node-v0.10.28-linux-arm-pi node
chmod a+rw /opt/node/lib/node_modules
chmod a+rw /opt/node/bin
echo 'PATH=$PATH:/opt/node/bin' > /etc/profile.d/node.sh

the only mod I did was change all 10.25 to 10.28 which was the latest linux-arm-pi at the time

sh: 0: getcwd() failed: No such file or directory on cited drive

Try the following command, it worked for me.

cd; cd -

shell init issue when click tab, what's wrong with getcwd?

This usually occurs when your current directory does not exist anymore. Most likely, from another terminal you remove that directory (from within a script or whatever). To get rid of this, in case your current directory was recreated in the meantime, just cd to another (existing) directory and then cd back; the simplest would be: cd; cd -.

Determine command line working directory when running node bin script

Alternatively, if you want to solely obtain the current directory of the current NodeJS script, you could try something simple like this. Note that this will not work in the Node CLI itself:

var fs = require('fs'),
    path = require('path');

var dirString = path.dirname(fs.realpathSync(__filename));

// output example: "/Users/jb/workspace/abtest"
console.log('directory to start walking...', dirString);

Can't install any packages in Node.js using "npm install"

If you happened to run npm install command on Windows, first make sure you open your command prompt with Administration Privileges. That's what solved the issue for me.

Not receiving Google OAuth refresh token

Using offline access and prompt:consent worked well to me:

   auth2 = gapi.auth2.init({
                    client_id: '{cliend_id}' 
   });

   auth2.grantOfflineAccess({prompt:'consent'}).then(signInCallback); 

How to convert image into byte array and byte array to base64 String in android?

Try this:

// convert from bitmap to byte array
public byte[] getBytesFromBitmap(Bitmap bitmap) {
    ByteArrayOutputStream stream = new ByteArrayOutputStream();
    bitmap.compress(CompressFormat.JPEG, 70, stream);
    return stream.toByteArray();
}

// get the base 64 string
String imgString = Base64.encodeToString(getBytesFromBitmap(someImg), 
                       Base64.NO_WRAP);

Determine project root from a running node.js application

At top of main file add:

mainDir = __dirname;

Then use it in any file you need:

console.log('mainDir ' + mainDir);
  • mainDir is defined globally, if you need it only in current file - use __dirname instead.
  • main file is usually in root folder of the project and is named like main.js, index.js, gulpfile.js.

What's the difference between process.cwd() vs __dirname?

Knowing the scope of each can make things easier to remember.

process is node's global object, and .cwd() returns where node is running.

__dirname is module's property, and represents the file path of the module. In node, one module resides in one file.

Similarly, __filename is another module's property, which holds the file name of the module.

npm can't find package.json

I had a similar problem with npm. The problem was that I had the project inside two folders of the same name. I resolved it by renaming one of the folders to something else (outer folder recommended).

How to find if directory exists in Python

#You can also check it get help for you

if not os.path.isdir('mydir'):
    print('new directry has been created')
    os.system('mkdir mydir')

os.path.dirname(__file__) returns empty

Because os.path.abspath = os.path.dirname + os.path.basename does not hold. we rather have

os.path.dirname(filename) + os.path.basename(filename) == filename

Both dirname() and basename() only split the passed filename into components without taking into account the current directory. If you want to also consider the current directory, you have to do so explicitly.

To get the dirname of the absolute path, use

os.path.dirname(os.path.abspath(__file__))

Open file in a relative location in Python

import os
def file_path(relative_path):
    dir = os.path.dirname(os.path.abspath(__file__))
    split_path = relative_path.split("/")
    new_path = os.path.join(dir, *split_path)
    return new_path

with open(file_path("2091/data.txt"), "w") as f:
    f.write("Powerful you have become.")

How to install lxml on Ubuntu

Since you're on Ubuntu, don't bother with those source packages. Just install those development packages using apt-get.

apt-get install libxml2-dev libxslt1-dev python-dev

If you're happy with a possibly older version of lxml altogether though, you could try

apt-get install python-lxml

and be done with it. :)

How do I get IntelliJ to recognize common Python modules?

Have you set up a python interpreter facet?

Open Project Structure CTRL+ALT+SHIFT+S

Project settings -> Facets -> expand Python click on child -> Python Interpreter

Then:

Project settings -> Modules -> Expand module -> Python -> Dependencies -> select Python module SDK

How to input a regex in string.replace?

I would go like this (regex explained in comments):

import re

# If you need to use the regex more than once it is suggested to compile it.
pattern = re.compile(r"</{0,}\[\d+>")

# <\/{0,}\[\d+>
# 
# Match the character “<” literally «<»
# Match the character “/” literally «\/{0,}»
#    Between zero and unlimited times, as many times as possible, giving back as needed (greedy) «{0,}»
# Match the character “[” literally «\[»
# Match a single digit 0..9 «\d+»
#    Between one and unlimited times, as many times as possible, giving back as needed (greedy) «+»
# Match the character “>” literally «>»

subject = """this is a paragraph with<[1> in between</[1> and then there are cases ... where the<[99> number ranges from 1-100</[99>. 
and there are many other lines in the txt files
with<[3> such tags </[3>"""

result = pattern.sub("", subject)

print(result)

If you want to learn more about regex I recomend to read Regular Expressions Cookbook by Jan Goyvaerts and Steven Levithan.

libxml install error using pip

On osx 10.10.5 and in a virtualenv, maybe you can resolve that problem like below:

sudo C_INCLUDE_PATH=/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.11.sdk/usr/include/libxml2:/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.11.sdk/usr/include/libxml2/libxml:/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.11.sdk/usr/include pip install -r lxml

How to use S_ISREG() and S_ISDIR() POSIX Macros?

You're using S_ISREG() and S_ISDIR() correctly, you're just using them on the wrong thing.

In your while((dit = readdir(dip)) != NULL) loop in main, you're calling stat on currentPath over and over again without changing currentPath:

if(stat(currentPath, &statbuf) == -1) {
    perror("stat");
    return errno;
}

Shouldn't you be appending a slash and dit->d_name to currentPath to get the full path to the file that you want to stat? Methinks that similar changes to your other stat calls are also needed.

How can I find script's directory?

Use os.path.abspath('')

Non-alphanumeric list order from os.listdir()

The proposed combination of os.listdir and sorted commands generates the same result as ls -l command under Linux. The following example verifies this assumption:

user@user-PC:/tmp/test$ touch 3a 4a 5a b c d1 d2 d3 k l p0 p1 p3 q 410a 409a 408a 407a
user@user-PC:/tmp/test$ ls -l
total 0
-rw-rw-r-- 1 user user 0 Feb  15 10:31 3a
-rw-rw-r-- 1 user user 0 Feb  15 10:31 407a
-rw-rw-r-- 1 user user 0 Feb  15 10:31 408a
-rw-rw-r-- 1 user user 0 Feb  15 10:31 409a
-rw-rw-r-- 1 user user 0 Feb  15 10:31 410a
-rw-rw-r-- 1 user user 0 Feb  15 10:31 4a
-rw-rw-r-- 1 user user 0 Feb  15 10:31 5a
-rw-rw-r-- 1 user user 0 Feb  15 10:31 b
-rw-rw-r-- 1 user user 0 Feb  15 10:31 c
-rw-rw-r-- 1 user user 0 Feb  15 10:31 d1
-rw-rw-r-- 1 user user 0 Feb  15 10:31 d2
-rw-rw-r-- 1 user user 0 Feb  15 10:31 d3
-rw-rw-r-- 1 user user 0 Feb  15 10:31 k
-rw-rw-r-- 1 user user 0 Feb  15 10:31 l
-rw-rw-r-- 1 user user 0 Feb  15 10:31 p0
-rw-rw-r-- 1 user user 0 Feb  15 10:31 p1
-rw-rw-r-- 1 user user 0 Feb  15 10:31 p3
-rw-rw-r-- 1 user user 0 Feb  15 10:31 q

user@user-PC:/tmp/test$ python
Python 2.7.6 (default, Jun 22 2015, 17:58:13) 
[GCC 4.8.2] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import os
>>> os.listdir( './' )
['d3', 'k', 'p1', 'b', '410a', '5a', 'l', 'p0', '407a', '409a', '408a', 'd2', '4a', 'p3', '3a', 'q', 'c', 'd1']
>>> sorted( os.listdir( './' ) )
['3a', '407a', '408a', '409a', '410a', '4a', '5a', 'b', 'c', 'd1', 'd2', 'd3', 'k', 'l', 'p0', 'p1', 'p3', 'q']
>>> exit()
user@user-PC:/tmp/test$ 

So, for someone who wants to reproduce the result of the well-known ls -l command in their python code, sorted( os.listdir( DIR ) ) works pretty well.

Argparse optional positional arguments?

parser.add_argument also has a switch required. You can use required=False. Here is a sample snippet with Python 2.7:

parser = argparse.ArgumentParser(description='get dir')
parser.add_argument('--dir', type=str, help='dir', default=os.getcwd(), required=False)
args = parser.parse_args()

How to reliably open a file in the same directory as a Python script

Ok here is what I do

sys.argv is always what you type into the terminal or use as the file path when executing it with python.exe or pythonw.exe

For example you can run the file text.py several ways, they each give you a different answer they always give you the path that python was typed.

    C:\Documents and Settings\Admin>python test.py
    sys.argv[0]: test.py
    C:\Documents and Settings\Admin>python "C:\Documents and Settings\Admin\test.py"
    sys.argv[0]: C:\Documents and Settings\Admin\test.py

Ok so know you can get the file name, great big deal, now to get the application directory you can know use os.path, specifically abspath and dirname

    import sys, os
    print os.path.dirname(os.path.abspath(sys.argv[0]))

That will output this:

   C:\Documents and Settings\Admin\

it will always output this no matter if you type python test.py or python "C:\Documents and Settings\Admin\test.py"

The problem with using __file__ Consider these two files test.py

import sys
import os

def paths():
        print "__file__: %s" % __file__
        print "sys.argv: %s" % sys.argv[0]

        a_f = os.path.abspath(__file__)
        a_s = os.path.abspath(sys.argv[0])

        print "abs __file__: %s" % a_f
        print "abs sys.argv: %s" % a_s

if __name__ == "__main__":
    paths()

import_test.py

import test
import sys

test.paths()

print "--------"
print __file__
print sys.argv[0]

Output of "python test.py"

C:\Documents and Settings\Admin>python test.py
__file__: test.py
sys.argv: test.py
abs __file__: C:\Documents and Settings\Admin\test.py
abs sys.argv: C:\Documents and Settings\Admin\test.py

Output of "python test_import.py"

C:\Documents and Settings\Admin>python test_import.py
__file__: C:\Documents and Settings\Admin\test.pyc
sys.argv: test_import.py
abs __file__: C:\Documents and Settings\Admin\test.pyc
abs sys.argv: C:\Documents and Settings\Admin\test_import.py
--------
test_import.py
test_import.py

So as you can see file gives you always the python file it is being run from, where as sys.argv[0] gives you the file that you ran from the interpreter always. Depending on your needs you will need to choose which one best fits your needs.

Python base64 data decode

import base64
coded_string = '''Q5YACgA...'''
base64.b64decode(coded_string)

worked for me. At the risk of pasting an offensively-long result, I got:

>>> base64.b64decode(coded_string)
2: 'C\x96\x00\n\x00\x00\x00\x00C\x96\x00\x1b\x00\x00\x00\x00C\x96\x00-\x00\x00\x00\x00C\x96\x00?\x00\x00\x00\x00C\x96\x07M\x00\x00\x00\x00C\x96\x07_\x00\x00\x00\x00C\x96\x07p\x00\x00\x00\x00C\x96\x07\x82\x00\x00\x00\x00C\x96\x07\x94\x00\x00\x00\x00C\x96\x07\xa6Cq\xf0\x7fC\x96\x07\xb8DJ\x81\xc7C\x96\x07\xcaD\xa5\x9dtC\x96\x07\xdcD\xb6\x97\x11C\x96\x07\xeeD\x8b\x8flC\x96\x07\xffD\x03\xd4\xaaC\x96\x08\x11B\x05&\xdcC\x96\x08#\x00\x00\x00\x00C\x96\x085C\x0c\xc9\xb7C\x96\x08GCy\xc0\xebC\x96\x08YC\x81\xa4xC\x96\x08kC\x0f@\x9bC\x96\x08}\x00\x00\x00\x00C\x96\x08\x8e\x00\x00\x00\x00C\x96\x08\xa0\x00\x00\x00\x00C\x96\x08\xb2\x00\x00\x00\x00C\x96\x86\xf9\x00\x00\x00\x00C\x96\x87\x0b\x00\x00\x00\x00C\x96\x87\x1d\x00\x00\x00\x00C\x96\x87/\x00\x00\x00\x00C\x96\x87AA\x0b\xe7PC\x96\x87SCI\xf5gC\x96\x87eC\xd4J\xeaC\x96\x87wD\r\x17EC\x96\x87\x89D\x00F6C\x96\x87\x9bC\x9cg\xdeC\x96\x87\xadB\xd56\x0cC\x96\x87\xbf\x00\x00\x00\x00C\x96\x87\xd1\x00\x00\x00\x00C\x96\x87\xe3\x00\x00\x00\x00C\x96\x87\xf5\x00\x00\x00\x00C\x9cY}\x00\x00\x00\x00C\x9cY\x90\x00\x00\x00\x00C\x9cY\xa4\x00\x00\x00\x00C\x9cY\xb7\x00\x00\x00\x00C\x9cY\xcbC\x1f\xbd\xa3C\x9cY\xdeCCz{C\x9cY\xf1CD\x02\xa7C\x9cZ\x05C+\x9d\x97C\x9cZ\x18C\x03R\xe3C\x9cZ,\x00\x00\x00\x00C\x9cZ?
[stuff omitted as it exceeded SO's body length limits]
\xbb\x00\x00\x00\x00D\xc5!7\x00\x00\x00\x00D\xc5!\xb2\x00\x00\x00\x00D\xc7\x14x\x00\x00\x00\x00D\xc7\x14\xf6\x00\x00\x00\x00D\xc7\x15t\x00\x00\x00\x00D\xc7\x15\xf2\x00\x00\x00\x00D\xc7\x16pC5\x9f\xf9D\xc7\x16\xeeC[\xb5\xf5D\xc7\x17lCG\x1b;D\xc7\x17\xeaB\xe3\x0b\xa6D\xc7\x18h\x00\x00\x00\x00D\xc7\x18\xe6\x00\x00\x00\x00D\xc7\x19d\x00\x00\x00\x00D\xc7\x19\xe2\x00\x00\x00\x00D\xc7\xfe\xb4\x00\x00\x00\x00D\xc7\xff3\x00\x00\x00\x00D\xc7\xff\xb2\x00\x00\x00\x00D\xc8\x001\x00\x00\x00\x00'

What problem are you having, specifically?

How do I get the path to the current script with Node.js?

So basically you can do this:

fs.readFile(path.resolve(__dirname, 'settings.json'), 'UTF-8', callback);

Use resolve() instead of concatenating with '/' or '\' else you will run into cross-platform issues.

Note: __dirname is the local path of the module or included script. If you are writing a plugin which needs to know the path of the main script it is:

require.main.filename

or, to just get the folder name:

require('path').dirname(require.main.filename)

How to get the current plugin directory in WordPress?

Looking at your own answer @Bog, I think you want;

$plugin_dir_path = dirname(__FILE__);

List Directories and get the name of the Directory

This will print all the subdirectories of the current directory:

print [name for name in os.listdir(".") if os.path.isdir(name)]

I'm not sure what you're doing with split("-"), but perhaps this code will help you find a solution?

If you want the full pathnames of the directories, use abspath:

print [os.path.abspath(name) for name in os.listdir(".") if os.path.isdir(name)]

Note that these pieces of code will only get the immediate subdirectories. If you want sub-sub-directories and so on, you should use walk as others have suggested.

How do I get the path of the current executed file in Python?

You can't directly determine the location of the main script being executed. After all, sometimes the script didn't come from a file at all. For example, it could come from the interactive interpreter or dynamically generated code stored only in memory.

However, you can reliably determine the location of a module, since modules are always loaded from a file. If you create a module with the following code and put it in the same directory as your main script, then the main script can import the module and use that to locate itself.

some_path/module_locator.py:

def we_are_frozen():
    # All of the modules are built-in to the interpreter, e.g., by py2exe
    return hasattr(sys, "frozen")

def module_path():
    encoding = sys.getfilesystemencoding()
    if we_are_frozen():
        return os.path.dirname(unicode(sys.executable, encoding))
    return os.path.dirname(unicode(__file__, encoding))

some_path/main.py:

import module_locator
my_path = module_locator.module_path()

If you have several main scripts in different directories, you may need more than one copy of module_locator.

Of course, if your main script is loaded by some other tool that doesn't let you import modules that are co-located with your script, then you're out of luck. In cases like that, the information you're after simply doesn't exist anywhere in your program. Your best bet would be to file a bug with the authors of the tool.

"Fatal error: Cannot redeclare <function>"

I don't like function_exists('fun_name') because it relies on the function name being turned into a string, plus, you have to name it twice. Could easily break with refactoring.

Declare your function as a lambda expression (I haven't seen this solution mentioned):

$generate_salt = function()
{
    ...
};

And use thusly:

$salt = $generate_salt();

Then, at re-execution of said PHP code, the function simply overwrites the previous declaration.

Can't get Python to import from a different folder

After going through the answers given by these contributors above - Zorglub29, Tom, Mark, Aaron McMillin, lucasamaral, JoeyZhao, Kjeld Flarup, Procyclinsur, martin.zaenker, tooty44 and debugging the issue that I was facing I found out a different use case due to which I was facing this issue. Hence adding my observations below for anybody's reference.

In my code I had a cyclic import of classes. For example:

src
 |-- utilities.py (has Utilities class that uses Event class)  
 |-- consume_utilities.py (has Event class that uses Utilities class)
 |-- tests
      |-- test_consume_utilities.py (executes test cases that involves Event class)

I got following error when I tried to execute python -m pytest tests/test_utilities.py for executing UTs written in test_utilities.py.

ImportError while importing test module '/Users/.../src/tests/test_utilities.py'.
Hint: make sure your test modules/packages have valid Python names.
Traceback:
tests/test_utilities.py:1: in <module>
    from utilities import Utilities
...
...
E   ImportError: cannot import name 'Utilities'

The way I resolved the error was by re-factoring my code to move the functionality in cyclic import class so that I could remove the cyclic import of classes.

Note, I have __init__.py file in my 'src' folder as well as 'tests' folder and still was able to get rid of the 'ImportError' just by re-factoring the code.

Following stackoverflow link provides much more details on Circular dependency in Python.

SFTP in Python? (platform independent)

Paramiko supports SFTP. I've used it, and I've used Twisted. Both have their place, but you might find it easier to start with Paramiko.

How to list only top level directories in Python?

Filter the result using os.path.isdir() (and use os.path.join() to get the real path):

>>> [ name for name in os.listdir(thedir) if os.path.isdir(os.path.join(thedir, name)) ]
['ctypes', 'distutils', 'encodings', 'lib-tk', 'config', 'idlelib', 'xml', 'bsddb', 'hotshot', 'logging', 'doc', 'test', 'compiler', 'curses', 'site-packages', 'email', 'sqlite3', 'lib-dynload', 'wsgiref', 'plat-linux2', 'plat-mac']

How to get an absolute file path in Python

Install a third-party path module (found on PyPI), it wraps all the os.path functions and other related functions into methods on an object that can be used wherever strings are used:

>>> from path import path
>>> path('mydir/myfile.txt').abspath()
'C:\\example\\cwd\\mydir\\myfile.txt'

How do I get the path and name of the file that is currently executing?

import os
os.path.dirname(__file__) # relative directory path
os.path.abspath(__file__) # absolute file path
os.path.basename(__file__) # the file name only

How to resolve symbolic links in a shell script

Try this:

cd $(dirname $([ -L $0 ] && readlink -f $0 || echo $0))

Warning: #1265 Data truncated for column 'pdd' at row 1

You are most likely pushing a string 'NULL' to the table, rather then an actual NULL, but other things may be going on as well, an illustration:

mysql> CREATE TABLE date_test (pdd DATE NOT NULL);
Query OK, 0 rows affected (0.11 sec)

mysql> INSERT INTO date_test VALUES (NULL);
ERROR 1048 (23000): Column 'pdd' cannot be null
mysql> INSERT INTO date_test VALUES ('NULL');
Query OK, 1 row affected, 1 warning (0.05 sec)

mysql> show warnings;
+---------+------+------------------------------------------+
| Level   | Code | Message                                  |
+---------+------+------------------------------------------+
| Warning | 1265 | Data truncated for column 'pdd' at row 1 |
+---------+------+------------------------------------------+
1 row in set (0.00 sec)

mysql> SELECT * FROM date_test;
+------------+
| pdd        |
+------------+
| 0000-00-00 |
+------------+
1 row in set (0.00 sec)

mysql> ALTER TABLE date_test MODIFY COLUMN pdd DATE NULL;
Query OK, 1 row affected (0.15 sec)
Records: 1  Duplicates: 0  Warnings: 0

mysql> INSERT INTO date_test VALUES (NULL);
Query OK, 1 row affected (0.06 sec)

mysql> SELECT * FROM date_test;
+------------+
| pdd        |
+------------+
| 0000-00-00 |
| NULL       |
+------------+
2 rows in set (0.00 sec)

Cannot use special principal dbo: Error 15405

To fix this, open the SQL Server Management Studio and click New Query. Then type:

USE mydatabase
exec sp_changedbowner 'sa', 'true'

Is Eclipse the best IDE for Java?

There is no best IDE. You make it as good as you get used using it.

Concatenating null strings in Java

This is behavior specified in the Java API's String.valueOf(Object) method. When you do concatenation, valueOf is used to get the String representation. There is a special case if the Object is null, in which case the string "null" is used.

public static String valueOf(Object obj)

Returns the string representation of the Object argument.

Parameters: obj - an Object.

Returns:

if the argument is null, then a string equal to "null"; otherwise, the value of obj.toString() is returned.

ImproperlyConfigured: You must either define the environment variable DJANGO_SETTINGS_MODULE or call settings.configure() before accessing settings

In my case it was python path issue.

#1 First set your PYTHONPATH

#2 then set DJANGO_SETTINGS_MODULE

then run django-admin shell command (django-admin dbshell)
(venv) shakeel@workstation:~/project_path$ export PYTHONPATH=/home/shakeel/project_path
(venv) shakeel@workstation:~/project_path$ export DJANGO_SETTINGS_MODULE=my_project.settings
(venv) shakeel@workstation:~/project_path$ django-admin dbshell
SQLite version 3.22.0 2018-01-22 18:45:57
Enter ".help" for usage hints.
sqlite>

otherwise python manage.py shell works like charm.

JavaScript file upload size validation

JQuery example provided in this thread was extremely outdated, and google wasn't helpful at all so here is my revision:

 <script type="text/javascript">
        $('#image-file').on('change', function() {
            console.log($(this)[0].files[0].name+' file size is: ' + $(this)[0].files[0].size/1024/1024 + 'Mb');
        });
    </script>

How to resolve git error: "Updates were rejected because the tip of your current branch is behind"

This worked for me:

git branch

Copy the current branch name to clipboard

git pull origin <paste-branch-name>
git push

How to replace part of string by position?

string s = "ABCDEFGH";
s= s.Remove(3, 2).Insert(3, "ZX");

How to get the public IP address of a user in C#

 private string GetClientIpaddress()
    {
        string ipAddress = string.Empty;
        ipAddress = HttpContext.Current.Request.ServerVariables["HTTP_X_FORWARDED_FOR"];
        if (ipAddress == "" || ipAddress == null)
        {
            ipAddress = HttpContext.Current.Request.ServerVariables["REMOTE_ADDR"];
            return ipAddress;
        }
        else
        {
            return ipAddress;
        }
    }

How do I write data to csv file in columns and rows from a list in python?

import pandas as pd
header=['a','b','v']
df=pd.DataFrame(columns=header)
for i in range(len(doc_list)):
  d_id=(test_data.filenames[i]).split('\\')
  doc_id.append(d_id[len(d_id)-1])
  df['a']=doc_id
print(df.head())
df[column_names_to_be_updated]=np.asanyarray(data)
print(df.head())
df.to_csv('output.csv')

Using pandas dataframe,we can write to csv. First create a dataframe as per the your needs for storing in csv. Then create csv of the dataframe using pd.DataFrame.to_csv() API.

Node.js get file extension

Update

Since the original answer, extname() has been added to the path module, see Snowfish answer

Original answer:

I'm using this function to get a file extension, because I didn't find a way to do it in an easier way (but I think there is) :

function getExtension(filename) {
    var ext = path.extname(filename||'').split('.');
    return ext[ext.length - 1];
}

you must require 'path' to use it.

another method which does not use the path module :

function getExtension(filename) {
    var i = filename.lastIndexOf('.');
    return (i < 0) ? '' : filename.substr(i);
}

Convert JSON array to Python list

Tested on Ideone.


import json
array = '{"fruits": ["apple", "banana", "orange"]}'
data  = json.loads(array)
fruits_list = data['fruits']
print fruits_list

"Items collection must be empty before using ItemsSource."

Exception

Items collection must be empty before using ItemsSource.

This exception occurs when you add items to the ItemsSource through different sources. So Make sure you haven't accidentally missed a tag, misplaced a tag, added extra tags, or miswrote a tag.

<!--Right-->

<ItemsControl ItemsSource="{Binding MyItems}">
     <ItemsControl.ItemsPanel.../>
     <ItemsControl.MyAttachedProperty.../>
     <FrameworkElement.ActualWidth.../>
</ItemsControl>


<!--WRONG-->

<ItemsControl ItemsSource="{Binding MyItems}">
     <Grid.../>
     <Button.../>
     <DataTemplate.../>
     <Heigth.../>
</ItemsControl>

While ItemsControl.ItemsSource is already set through Binding, other items (Grid, Button, ...) can't be added to the source. However while ItemsSource is not in-use the following code is allowed:

<!--Right-->
<ItemsControl>
     <Button.../>
     <TextBlock.../>
     <sys:String.../>
</ItemsControl>

notice the missing ItemsSource="{Binding MyItems}" part.

How to get rid of the "No bootable medium found!" error in Virtual Box?

FIX 1:

Step1: Go to settings > then select the following configuration(Disable Floppy)

Config

Alternatively, you can press F12 while booting the Guest OS and select CD from there, this is a one time setting, good enough for the installation.

Step 2: Place your Existing Guest OS bootable CD in the Disk Drive and start the Guest OS.

FIX 2:

Go to Settings > And Perform the following:

Config1

FIX 3:

Try Fix 1 & 2 together..

Copy file or directories recursively in Python

shutil.copy and shutil.copy2 are copying files.

shutil.copytree copies a folder with all the files and all subfolders. shutil.copytree is using shutil.copy2 to copy the files.

So the analog to cp -r you are saying is the shutil.copytree because cp -r targets and copies a folder and its files/subfolders like shutil.copytree. Without the -r cp copies files like shutil.copy and shutil.copy2 do.

Loading local JSON file

function readTextFile(srcfile) {
        try { //this is for IE
            var fso = new ActiveXObject("Scripting.FileSystemObject");;
            if (fso.FileExists(srcfile)) {
                var fileReader = fso.OpenTextFile(srcfile, 1);
                var line = fileReader.ReadLine();
                var jsonOutput = JSON.parse(line); 
            }

        } catch (e) {

        }
}

readTextFile("C:\\Users\\someuser\\json.txt");

What I did was, first of all, from network tab, record the network traffic for the service, and from response body, copy and save the json object in a local file. Then call the function with the local file name, you should be able to see the json object in jsonOutout above.

ReactJS - How to use comments?

On the other hand, the following is a valid comment, pulled directly from a working application:

render () {
    return <DeleteResourceButton
            //confirm
            onDelete={this.onDelete.bind(this)}
            message="This file will be deleted from the server."
           />
}

Apparantly, when inside the angle brackets of a JSX element, the // syntax is valid, but the {/**/} is invalid. The following breaks:

render () {
    return <DeleteResourceButton
            {/*confirm*/}
            onDelete={this.onDelete.bind(this)}
            message="This file will be deleted from the server."
           />
}

Inserting created_at data with Laravel

In your User model, add the following line in the User class:

public $timestamps = true;

Now, whenever you save or update a user, Laravel will automatically update the created_at and updated_at fields.


Update:
If you want to set the created at manually you should use the date format Y-m-d H:i:s. The problem is that the format you have used is not the same as Laravel uses for the created_at field.

Update: Nov 2018 Laravel 5.6 "message": "Access level to App\\Note::$timestamps must be public", Make sure you have the proper access level as well. Laravel 5.6 is public.

Laravel 5.4 redirection to custom url after login

For newer versions of Laravel, please replace protected $redirectTo = RouteServiceProvider::HOME; with protected $redirectTo = '/newurl'; and replace newurl accordingly.

Tested with Laravel version-6

Checking if a date is valid in javascript

Try this:

var date = new Date();
console.log(date instanceof Date && !isNaN(date.valueOf()));

This should return true.

UPDATED: Added isNaN check to handle the case commented by Julian H. Lam

Regular expression to match any character being repeated more than 10 times

use the {10,} operator:

$: cat > testre
============================
==
==============

$: grep -E '={10,}' testre
============================
==============

Java out.println() how is this possible?

Or simply:

System.out.println("Some text");

Checking password match while typing

Here's a working jsfiddle

http://jsfiddle.net/dbwMY/

Things to note:

  • validate event handler bound within the document.ready function - otherwise the inputs won't exist when the JS is loaded
  • using keyup

In saying that, validation is a solved problem there are frameworks that implement this functionality.

http://bassistance.de/jquery-plugins/jquery-plugin-validation/

I'd suggest using one of these rather than reimplementing Validation for every app you write.

A non-blocking read on a subprocess.PIPE in Python

Things are a lot better in modern Python.

Here's a simple child program, "hello.py":

#!/usr/bin/env python3

while True:
    i = input()
    if i == "quit":
        break
    print(f"hello {i}")

And a program to interact with it:

import asyncio


async def main():
    proc = await asyncio.subprocess.create_subprocess_exec(
        "./hello.py", stdin=asyncio.subprocess.PIPE, stdout=asyncio.subprocess.PIPE
    )
    proc.stdin.write(b"bob\n")
    print(await proc.stdout.read(1024))
    proc.stdin.write(b"alice\n")
    print(await proc.stdout.read(1024))
    proc.stdin.write(b"quit\n")
    await proc.wait()


asyncio.run(main())

That prints out:

b'hello bob\n'
b'hello alice\n'

Note that the actual pattern, which is also by almost all of the previous answers, both here and in related questions, is to set the child's stdout file descriptor to non-blocking and then poll it in some sort of select loop. These days, of course, that loop is provided by asyncio.

How do I upgrade the Python installation in Windows 10?

_x000D_
_x000D_
#Update your pip version
python -m pip install pip
#else
python -m pip install –upgrade pip
_x000D_
_x000D_
_x000D_

char initial value in Java

As you will see in linked discussion there is no need for initializing char with special character as it's done for us and is represented by '\u0000' character code.

So if we want simply to check if specified char was initialized just write:

if(charVariable != '\u0000'){
 actionsOnInitializedCharacter();
}

Link to question: what's the default value of char?

What is HEAD in Git?

A branch is actually a pointer that holds a commit ID such as 17a5. HEAD is a pointer to a branch the user is currently working on.

HEAD has a reference filw which looks like this:

ref:

You can check these files by accessing .git/HEAD .git/refs that are in the repository you are working in.

Simplest way to detect a mobile device in PHP

You only need to include user_agent.php file which can be found from Mobile device detection in PHP page and use the following code.

<?php
//include file
include_once 'user_agent.php';

//create an instance of UserAgent class
$ua = new UserAgent();

//if site is accessed from mobile, then redirect to the mobile site.
if($ua->is_mobile()){
   header("Location:http://m.codexworld.com");
   exit;
}
?>

Convert boolean result into number/integer

The typed way to do this would be:

Number(true) // 1
Number(false) // 0

Compare every item to every other item in ArrayList

In some cases this is the best way because your code may have change something and j=i+1 won't check that.

for (int i = 0; i < list.size(); i++){  
    for (int j = 0; j < list.size(); j++) {
                if(i == j) {
               //to do code here
                    continue;
                }

}

}

The way to check a HDFS directory's size?

hdfs dfs -count <dir>

info from man page:

-count [-q] [-h] [-v] [-t [<storage type>]] [-u] <path> ... :
  Count the number of directories, files and bytes under the paths
  that match the specified file pattern.  The output columns are:
  DIR_COUNT FILE_COUNT CONTENT_SIZE PATHNAME
  or, with the -q option:
  QUOTA REM_QUOTA SPACE_QUOTA REM_SPACE_QUOTA
        DIR_COUNT FILE_COUNT CONTENT_SIZE PATHNAME

how to change the dist-folder path in angular-cli after 'ng build'

for github pages I Use

ng build --prod --base-href "https://<username>.github.io/<RepoName>/" --output-path=docs

This is what that copies output into the docs folder : --output-path=docs

How to pop an alert message box using PHP?

See this example :

<?php
echo "<div id='div1'>text</div>"
?>

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="utf-8" />
    <title></title>
    <script src="js/jquery1.3.2/jquery.min.js"></script>

    <script type="text/javascript">
        $(document).ready(function () {
            $('#div1').click(function () {
                alert('I clicked');
            });
        });
</script>
</head>
<body>

</body>
</html>

For each row in an R dataframe

you can do something for a list object,

data("mtcars")
rownames(mtcars)
data <- list(mtcars ,mtcars, mtcars, mtcars);data

out1 <- NULL 
for(i in seq_along(data)) { 
  out1[[i]] <- data[[i]][rownames(data[[i]]) != "Volvo 142E", ] } 
out1

Or a data frame,

data("mtcars")
df <- mtcars
out1 <- NULL 
for(i in 1:nrow(df)) {
  row <- rownames(df[i,])
  # do stuff with row
  out1 <- df[rownames(df) != "Volvo 142E",]
  
}
out1 

HTML Button Close Window

When in the onclick attribute you do not need to specify that it is Javascript.

<button type="button" 
        onclick="window.open('', '_self', ''); window.close();">Discard</button>

This should do it. In order to close it your page needs to be opened by the script, hence the window.open. Here is an article explaining this in detail:

Click Here

If all else fails, you should also add a message asking the user to manually close the window, as there is no cross-browser solution for this, especially with older browsers such as IE 8.

Fully custom validation error message with Rails

One solution might be to change the i18n default error format:

en:
  errors:
    format: "%{message}"

Default is format: %{attribute} %{message}

Android - Set text to TextView

Try This:

TextView err = (TextView)findViewById(R.id.text);

Ensure you import TextView.

Node.js: Python not found exception due to node-sass and node-gyp

node-gyp requires old Python 2 - link

If you don't have it installed - check other answers about installing windows-build-tools.

If you are like me and have both old and new Python versions installed, chances are that node-gyp tries to use Python 3. And that results in the following SyntaxError: invalid syntax error.

I found an article about having two Python versions installed. And they recommend renaming Python 2.* executable to python2.exe - link.

So it looks like node-gyp is expecting to find old Python 2 executable renamed. Hence the error message:

...
gyp verb check python checking for Python executable "python2" in the PATH
gyp verb `which` failed Error: not found: python2
...

Once I renamed C:\Python27\python.exe to C:\Python27\python2.exe it worked without errors.

Of course, both C:\Python27\ and C:\Python39\ have to be in PATH variable. And no need in setting old Python version in npm config. Your default Python still will be the new one.

Global npm install location on windows?

Just press windows button and type %APPDATA% and type enter.

Above is the location where you can find \npm\node_modules folder. This is where global modules sit in your system.

Android Studio Rendering Problems : The following classes could not be found

Please see the following link - here is where I found a solution that worked for me.

Rendering problems in Android Studio v 1.1 / 1.2

Changing the Android Version when rendering layouts worked for me - I flipped it back to 21 and my "Hello World" app then rendered the basic activity_main.xml OK - at 22 I got this error. I borrowed the image from this posting to show you where to click in the Design tab of the XML preview. What is wierd is that when I flip back to 22 the problem is still gone :-).

enter image description here

Convert IQueryable<> type object to List<T> type?

Here's a couple of extension methods I've jury-rigged together to convert IQueryables and IEnumerables from one type to another (i.e. DTO). It's mainly used to convert from a larger type (i.e. the type of the row in the database that has unneeded fields) to a smaller one.

The positive sides of this approach are:

  • it requires almost no code to use - a simple call to .Transform<DtoType>() is all you need
  • it works just like .Select(s=>new{...}) i.e. when used with IQueryable it produces the optimal SQL code, excluding Type1 fields that DtoType doesn't have.

LinqHelper.cs:

public static IQueryable<TResult> Transform<TResult>(this IQueryable source)
{
    var resultType = typeof(TResult);
    var resultProperties = resultType.GetProperties().Where(p => p.CanWrite);

    ParameterExpression s = Expression.Parameter(source.ElementType, "s");

    var memberBindings =
        resultProperties.Select(p =>
            Expression.Bind(typeof(TResult).GetMember(p.Name)[0], Expression.Property(s, p.Name))).OfType<MemberBinding>();

    Expression memberInit = Expression.MemberInit(
        Expression.New(typeof(TResult)),
        memberBindings
        );

    var memberInitLambda = Expression.Lambda(memberInit, s);

    var typeArgs = new[]
        {
            source.ElementType, 
            memberInit.Type
        };

    var mc = Expression.Call(typeof(Queryable), "Select", typeArgs, source.Expression, memberInitLambda);

    var query = source.Provider.CreateQuery<TResult>(mc);

    return query;
}

public static IEnumerable<TResult> Transform<TResult>(this IEnumerable source)
{
    return source.AsQueryable().Transform<TResult>();
}

How can I get the URL of the current tab from a Google Chrome extension?

This Solution is already TESTED.

set permissions for API in manifest.json

"permissions": [ ...
   "tabs",
    "activeTab",
    "<all_urls>"
]

On first load call function. https://developer.chrome.com/extensions/tabs#event-onActivated

chrome.tabs.onActivated.addListener((activeInfo) => {  
  sendCurrentUrl()
})

On change call function. https://developer.chrome.com/extensions/tabs#event-onSelectionChanged

chrome.tabs.onSelectionChanged.addListener(() => {
  sendCurrentUrl()
})

the function to get the URL

function sendCurrentUrl() {
  chrome.tabs.getSelected(null, function(tab) {
    var tablink = tab.url
    console.log(tablink)
  })

List files recursively in Linux CLI with path relative to the current directory

In the fish shell, you can do this to list all pdfs recursively, including the ones in the current directory:

$ ls **pdf

Just remove 'pdf' if you want files of any type.

How to get a jqGrid cell value when editing

I think that Aidan's answer is by far the best.

$('#yourgrid').jqGrid("editCell", 0, 0, false);

This commits any current edits, giving you access to the real value. I prefer it because:

  • You don't have to hard-code any cell references in.
    • It is particularly well suited to using getRowData() to get the entire grid, as it doesn't care which cell you've just been editing.
    • You're not trying to parse some markup generated by jqGrid which may change in future.
    • If the user is saving, then ending the edit session is likely the behaviour they would want anyway.

Android: How to open a specific folder via Intent and show its content in a file browser?

Today, you should be representing a folder using its content: URI as obtained from the Storage Access Framework, and opening it should be as simple as:

Intent i = new Intent(Intent.ACTION_VIEW, uri);
startActivity(i);

Alas, the Files app currently contains a bug that causes it to crash when you try this using the external storage provider. Folders from third party providers however can be displayed in this way.

Efficient SQL test query or validation query that will work across all (or most) databases

How about

SELECT user()

I use this before.MySQL, H2 is OK, I don't know others.

Java function for arrays like PHP's join()?

In Java 8 you can use

1) Stream API :

String[] a = new String[] {"a", "b", "c"};
String result = Arrays.stream(a).collect(Collectors.joining(", "));

2) new String.join method: https://stackoverflow.com/a/21756398/466677

3) java.util.StringJoiner class: http://docs.oracle.com/javase/8/docs/api/java/util/StringJoiner.html

how to get login option for phpmyadmin in xampp

Ya, it's working fine, but it can enter into localhost without entering password.

You can do it in another way by following these steps:

  1. In the browser, type: localhost/xampp/

  2. On the left side bar menu, click Security.

  3. Now you can see the subject table, and below the subject table you can see this link:
    http://localhost/security/xamppsecurity.php. Click this link.

  4. Now you can set the password as you want.

  5. Go to the xampp folder where you installed xampp. Open the xampp folder.

  6. Find and open the phpMyAdmin folder.

  7. Find and open the config.inc.php file with Notepad.

  8. Find the code below:

    $cfg['Servers'][$i]['auth_type'] = 'config';
    $cfg['Servers'][$i]['user'] = 'root';
    $cfg['Servers'][$i]['password'] = '';
    $cfg['Servers'][$i]['extension'] = 'mysqli';
    $cfg['Servers'][$i]['AllowNoPassword'] = true;
    
  9. Replace it with the code below:

    $cfg['Servers'][$i]['auth_type'] = 'cookie';
    $cfg['Servers'][$i]['user'] = 'root';
    $cfg['Servers'][$i]['password'] = '';
    $cfg['Servers'][$i]['extension'] = 'mysqli';
    $cfg['Servers'][$i]['AllowNoPassword'] = false;
    
  10. Save the file and run the localhost/phpmyadmin with the browser.

Creating a PHP header/footer

the simpler, the better.

index.php

<? 
if (empty($_SERVER['QUERY_STRING'])) { 
  $name="index"; 
} else { 
  $name=basename($_SERVER['QUERY_STRING']); 
} 
$file="txt/".$name.".htm"; 
if (is_readable($file)) { 
  include 'header.php';
  readfile($file);
} else { 
  header("HTTP/1.0 404 Not Found");
  exit;
} 
?>

header.php

<a href="index.php">Main page</a><br>
<a href=?about>About</a><br>
<a href=?links>Links</a><br>
<br><br> 

the actual static html pages stored in the txt folder in the page.htm format

What regular expression will match valid international phone numbers?

I use this one:

/([0-9\s\-]{7,})(?:\s*(?:#|x\.?|ext\.?|extension)\s*(\d+))?$/

Advantages: recognizes + or 011 beginnings, lets it be as long as needed, and handles many extension conventions. (#,x,ext,extension)

how I can show the sum of in a datagridview column?

//declare the total variable
int total = 0;
//loop through the datagrid and sum the column 
for(int i=0;i<datagridview1.Rows.Count;i++)
{
    total +=int.Parse(datagridview1.Rows[i].Cells["CELL NAME OR INDEX"].Value.ToString());

}
string tota

Get current controller in view

Other way to get current Controller name in View

@ViewContext.Controller.ValueProvider.GetValue("controller").RawValue

How to convert FileInputStream to InputStream?

InputStream is;

try {
    is = new FileInputStream("c://filename");

    is.close(); 
} catch (FileNotFoundException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
} catch (IOException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
}

return is;

Angularjs error Unknown provider

Make sure you are loading those modules (myApp.services and myApp.directives) as dependencies of your main app module, like this:

angular.module('myApp', ['myApp.directives', 'myApp.services']);

plunker: http://plnkr.co/edit/wxuFx6qOMfbuwPq1HqeM?p=preview

Setting an image button in CSS - image:active

This is what worked for me.

<!DOCTYPE html> 
<form action="desired Link">
  <button>  <img src="desired image URL"/>
  </button>
</form>
<style> 

</style>

Disable output buffering

(I've posted a comment, but it got lost somehow. So, again:)

  1. As I noticed, CPython (at least on Linux) behaves differently depending on where the output goes. If it goes to a tty, then the output is flushed after each '\n'
    If it goes to a pipe/process, then it is buffered and you can use the flush() based solutions or the -u option recommended above.

  2. Slightly related to output buffering:
    If you iterate over the lines in the input with

    for line in sys.stdin:
    ...

then the for implementation in CPython will collect the input for a while and then execute the loop body for a bunch of input lines. If your script is about to write output for each input line, this might look like output buffering but it's actually batching, and therefore, none of the flush(), etc. techniques will help that. Interestingly, you don't have this behaviour in pypy. To avoid this, you can use

while True: line=sys.stdin.readline()
...

Alternative to file_get_contents?

If the file is local as your comment about SITE_PATH suggest, it's pretty simple just execute the script and cache the result in a variable using the output control functions :

function print_xml_data_file()
{
    include(XML_DATA_FILE_DIRECTORY . 'cms/data.php');
}

function get_xml_data()
{
    ob_start();
    print_xml_data_file();
    $xml_file = ob_get_contents();
    ob_end_clean();
    return $xml_file;
}

If it's remote as lot of others said curl is the way to go. If it isn't present try socket_create or fsockopen. If nothing work... change your hosting provider.

How do I implement a callback in PHP?

The manual uses the terms "callback" and "callable" interchangeably, however, "callback" traditionally refers to a string or array value that acts like a function pointer, referencing a function or class method for future invocation. This has allowed some elements of functional programming since PHP 4. The flavors are:

$cb1 = 'someGlobalFunction';
$cb2 = ['ClassName', 'someStaticMethod'];
$cb3 = [$object, 'somePublicMethod'];

// this syntax is callable since PHP 5.2.3 but a string containing it
// cannot be called directly
$cb2 = 'ClassName::someStaticMethod';
$cb2(); // fatal error

// legacy syntax for PHP 4
$cb3 = array(&$object, 'somePublicMethod');

This is a safe way to use callable values in general:

if (is_callable($cb2)) {
    // Autoloading will be invoked to load the class "ClassName" if it's not
    // yet defined, and PHP will check that the class has a method
    // "someStaticMethod". Note that is_callable() will NOT verify that the
    // method can safely be executed in static context.

    $returnValue = call_user_func($cb2, $arg1, $arg2);
}

Modern PHP versions allow the first three formats above to be invoked directly as $cb(). call_user_func and call_user_func_array support all the above.

See: http://php.net/manual/en/language.types.callable.php

Notes/Caveats:

  1. If the function/class is namespaced, the string must contain the fully-qualified name. E.g. ['Vendor\Package\Foo', 'method']
  2. call_user_func does not support passing non-objects by reference, so you can either use call_user_func_array or, in later PHP versions, save the callback to a var and use the direct syntax: $cb();
  3. Objects with an __invoke() method (including anonymous functions) fall under the category "callable" and can be used the same way, but I personally don't associate these with the legacy "callback" term.
  4. The legacy create_function() creates a global function and returns its name. It's a wrapper for eval() and anonymous functions should be used instead.

How to run shell script on host from docker container?

The solution I use is to connect to the host over SSH and execute the command like this:

ssh -l ${USERNAME} ${HOSTNAME} "${SCRIPT}"

UPDATE

As this answer keeps getting up votes, I would like to remind (and highly recommend), that the account which is being used to invoke the script should be an account with no permissions at all, but only executing that script as sudo (that can be done from sudoers file).

socket programming multiple client to one server

See O'Reilly "Java Cookbook", Ian Darwin - recipe 17.4 Handling Multiple Clients.

Pay attention that accept() is not thread safe, so the call is wrapped within synchronized.

64: synchronized(servSock) {
65:     clientSocket = servSock.accept();
66: }

Windows 7: unable to register DLL - Error Code:0X80004005

Use following command should work on windows 7. don't forget to enclose the dll name with full path in double quotations.

C:\Windows\SysWOW64>regsvr32 "c:\dll.name" 

How can I export the schema of a database in PostgreSQL?

If you only want the create tables, then you can do pg_dump -s databasename | awk 'RS="";/CREATE TABLE[^;]*;/'

how to convert Lower case letters to upper case letters & and upper case letters to lower case letters

StringBuilder b = new StringBuilder();

Scanner s = new Scanner(System.in);
String n = s.nextLine();

for(int i = 0; i < n.length(); i++) {
    char c = n.charAt(i);

    if(Character.isLowerCase(c) == true) {
        b.append(String.valueOf(c).toUpperCase());
    }
    else {
        b.append(String.valueOf(c).toLowerCase());
    }
}

System.out.println(b);

Apache 2.4.6 on Ubuntu Server: Client denied by server configuration (PHP FPM) [While loading PHP file]

I recently ran into the same problem. I had to change my virtual hosts from:

<VirtualHost *:80>
  ServerName local.example.com

  DocumentRoot /home/example/public

  <Directory />
    Order allow,deny
    Allow from all
  </Directory>
</VirtualHost>

To:

<VirtualHost *:80>
  ServerName local.example.com

  DocumentRoot /home/example/public

  <Directory />
    Options All
    AllowOverride All
    Require all granted
  </Directory>
</VirtualHost>

compareTo() vs. equals()

"equals" compare objects and return true or false and "compare to" return 0 if is true or an number [> 0] or [< 0] if is false here an example:

<!-- language: lang-java -->
//Objects Integer
Integer num1 = 1;
Integer num2 = 1;
//equal
System.out.println(num1.equals(num2));
System.out.println(num1.compareTo(num2));
//New Value
num2 = 3;//set value
//diferent
System.out.println(num1.equals(num2));
System.out.println(num1.compareTo(num2));

Results:

num1.equals(num2) =true
num1.compareTo(num2) =0
num1.equals(num2) =false
num1.compareTo(num2) =-1

Documentation Compare to: https://docs.oracle.com/javase/7/docs/api/java/lang/Comparable.html

Documentation Equals : https://docs.oracle.com/javase/7/docs/api/java/lang/Object.html#equals(java.lang.Object)

How to write UTF-8 in a CSV file

The examples in the Python documentation show how to write Unicode CSV files: http://docs.python.org/2/library/csv.html#examples

(can't copy the code here because it's protected by copyright)

How to get First and Last record from a sql query?

last record :

SELECT * FROM `aboutus` order by id desc limit 1

first record :

SELECT * FROM `aboutus` order by id asc limit 1

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

These steps work for me:

  1. Download the Rcpp manually from WebSite (https://cran.r-project.org/web/packages/Rcpp/index.html)
  2. unzip the folder/files to "Rcpp" folder
  3. Locate the "library" folder under R install directory Ex: C:\R\R-3.3.1\library
  4. Copy the "Rcpp" folder to Library folder.

Good to go!!!

library(Rcpp)
library(ggplot2) 

What is the javascript filename naming convention?

I'm not aware of any particular convention for javascript files as they aren't really unique on the web versus css files or html files or any other type of file like that. There are some "safe" things you can do that make it less likely you will accidentally run into a cross platform issue:

  1. Use all lowercase filenames. There are some operating systems that are not case sensitive for filenames and using all lowercase prevents inadvertently using two files that differ only in case that might not work on some operating systems.
  2. Don't use spaces in the filename. While this technically can be made to work there are lots of reasons why spaces in filenames can lead to problems.
  3. A hyphen is OK for a word separator. If you want to use some sort of separator for multiple words instead of a space or camelcase as in various-scripts.js, a hyphen is a safe and useful and commonly used separator.
  4. Think about using version numbers in your filenames. When you want to upgrade your scripts, plan for the effects of browser or CDN caching. The simplest way to use long term caching (for speed and efficiency), but immediate and safe upgrades when you upgrade a JS file is to include a version number in the deployed filename or path (like jQuery does with jquery-1.6.2.js) and then you bump/change that version number whenever you upgrade/change the file. This will guarantee that no page that requests the newer version is ever served the older version from a cache.

Django CSRF check failing with an Ajax POST request

I have a solution. in my JS I have two functions. First to get Cookies (ie. csrftoken):

function getCookie(name) {
let cookieValue = null;
if (document.cookie && document.cookie !== '') {
    const cookies = document.cookie.split(';');
    for (let i = 0; i < cookies.length; i++) {
        const cookie = cookies[i].trim();
        // Does this cookie string begin with the name we want?
        if (cookie.substring(0, name.length + 1) === (name + '=')) {
            cookieValue = decodeURIComponent(cookie.substring(name.length + 1));
            break;
        }
    }
}
return cookieValue;

}

Second one is my ajax function. in this case it's for login and in fact doesn't return any thing, just pass values to set a session:

function LoginAjax() {


    //get scrftoken:
    const csrftoken = getCookie('csrftoken');

    var req = new XMLHttpRequest();
    var userName = document.getElementById("Login-Username");
    var password = document.getElementById("Login-Password");

    req.onreadystatechange = function () {
        if (this.readyState == 4 && this.status == 200) {            
            //read response loggedIn JSON show me if user logged in or not
            var respond = JSON.parse(this.responseText);            
            alert(respond.loggedIn);

        }
    }

    req.open("POST", "login", true);

    //following header set scrftoken to resolve problem
    req.setRequestHeader('X-CSRFToken', csrftoken);

    req.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
    req.send("UserName=" + userName.value + "&Password=" + password.value);
}

JavaScript - Get Portion of URL Path

If you have an abstract URL string (not from the current window.location), you can use this trick:

let yourUrlString = "http://example.com:3000/pathname/?search=test#hash";

let parser = document.createElement('a');
parser.href = yourUrlString;

parser.protocol; // => "http:"
parser.hostname; // => "example.com"
parser.port;     // => "3000"
parser.pathname; // => "/pathname/"
parser.search;   // => "?search=test"
parser.hash;     // => "#hash"
parser.host;     // => "example.com:3000"

Thanks to jlong

Catch Ctrl-C in C

Set up a trap (you can trap several signals with one handler):

signal (SIGQUIT, my_handler);
signal (SIGINT, my_handler);

Handle the signal however you want, but be aware of limitations and gotchas:

void my_handler (int sig)
{
  /* Your code here. */
}

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

Centering is one of the biggest issues in CSS. However, some tricks exist:

To center your table horizontally, you can set left and right margin to auto:

<style>
  #test {
    width:100%;
    height:100%;
  }
  table {
    margin: 0 auto; /* or margin: 0 auto 0 auto */
  }
</style>

To center it vertically, the only way is to use javascript:

var tableMarginTop = Math.round( (testHeight - tableHeight) / 2 );
$('table').css('margin-top', tableMarginTop) # with jQuery
$$('table')[0].setStyle('margin-top', tableMarginTop) # with Mootools

No vertical-align:middle is possible as a table is a block and not an inline element.

Edit

Here is a website that sums up CSS centering solutions: http://howtocenterincss.com/

How to query data out of the box using Spring data JPA by both Sort and Pageable?

in 2020, the accepted answer is kinda out of date since the PageRequest is deprecated, so you should use code like this :

Pageable page = PageRequest.of(pageable.getPageNumber(), pageable.getPageSize(), Sort.by("id").descending());
return repository.findAll(page);

How to get substring in C

If the task is only copying 4 characters, try for loops. If it's going to be more advanced and you're asking for a function, try strncpy. http://www.cplusplus.com/reference/clibrary/cstring/strncpy/

strncpy(sub1, baseString, 4);
strncpy(sub1, baseString+4, 4);
strncpy(sub1, baseString+8, 4);

or

for(int i=0; i<4; i++)
    sub1[i] = baseString[i];
sub1[4] = 0;
for(int i=0; i<4; i++)
    sub2[i] = baseString[i+4];
sub2[4] = 0;
for(int i=0; i<4; i++)
    sub3[i] = baseString[i+8];
sub3[4] = 0;

Prefer strncpy if possible.

Converting Varchar Value to Integer/Decimal Value in SQL Server

You can use it without casting such as:

select sum(`stuff`) as mySum from test;

Or cast it to decimal:

select sum(cast(`stuff` as decimal(4,2))) as mySum from test;

SQLFiddle

EDIT

For SQL Server, you can use:

select sum(cast(stuff as decimal(5,2))) as mySum from test;

SQLFiddle

How do I create a message box with "Yes", "No" choices and a DialogResult?

The MessageBox does produce a DialogResults

DialogResult r = MessageBox.Show("Some question here");

You can also specify the buttons easily enough. More documentation can be found at http://msdn.microsoft.com/en-us/library/ba2a6d06.aspx

How to detect orientation change in layout in Android?

Use the onConfigurationChanged method of Activity. See the following code:

@Override
public void onConfigurationChanged(@NotNull Configuration newConfig) {
    super.onConfigurationChanged(newConfig);

    // Checks the orientation of the screen
    if (newConfig.orientation == Configuration.ORIENTATION_LANDSCAPE) {
        Toast.makeText(this, "landscape", Toast.LENGTH_SHORT).show();
    } else if (newConfig.orientation == Configuration.ORIENTATION_PORTRAIT){
        Toast.makeText(this, "portrait", Toast.LENGTH_SHORT).show();
    }
}

You also have to edit the appropriate element in your manifest file to include the android:configChanges Just see the code below:

<activity android:name=".MyActivity"
          android:configChanges="orientation|keyboardHidden"
          android:label="@string/app_name">

NOTE: with Android 3.2 (API level 13) or higher, the "screen size" also changes when the device switches between portrait and landscape orientation. Thus, if you want to prevent runtime restarts due to orientation change when developing for API level 13 or higher, you must declare android:configChanges="orientation|screenSize" for API level 13 or higher.

Hope this will help you... :)

Difference between a class and a module

Module in Ruby, to a degree, corresponds to Java abstract class -- has instance methods, classes can inherit from it (via include, Ruby guys call it a "mixin"), but has no instances. There are other minor differences, but this much information is enough to get you started.

Convert negative data into positive data in SQL Server

The best solution is: from positive to negative or from negative to positive

For negative:

SELECT ABS(a) * -1 AS AbsoluteA, ABS(b) * -1 AS AbsoluteB
FROM YourTable

For positive:

SELECT ABS(a) AS AbsoluteA, ABS(b)  AS AbsoluteB
FROM YourTable

'Access-Control-Allow-Origin' issue when API call made from React (Isomorphic app)

I was having the same problem with the fetch command. A quick look at the docs from here tells us this:

If the server you are requesting from doesn't support CORS, you should get an error in the console indicating that the cross-origin request is blocked due to the CORS Access-Control-Allow-Origin header being missing.

You can use no-cors mode to request opaque resources.

fetch('https://bar.com/data.json', {
  mode: 'no-cors' // 'cors' by default
})
.then(function(response) {
  // Do something with response
});

Multiple conditions with CASE statements

Another way based on amadan:

    SELECT * FROM [Purchasing].[Vendor] WHERE  

      ( (@url IS null OR @url = '' OR @url = 'ALL') and   PurchasingWebServiceURL LIKE '%')
    or

       ( @url = 'blank' and  PurchasingWebServiceURL = '')
    or
        (@url = 'fail' and  PurchasingWebServiceURL NOT LIKE '%treyresearch%')
    or( (@url not in ('fail','blank','','ALL') and @url is not null and 
          PurchasingWebServiceUrl Like '%'+@ur+'%') 
END

JavaScript getElementByID() not working

You need to put the JavaScript at the end of the body tag.

It doesn't find it because it's not in the DOM yet!

You can also wrap it in the onload event handler like this:

window.onload = function() {
var refButton = document.getElementById( 'btnButton' );
refButton.onclick = function() {
   alert( 'I am clicked!' );
}
}

What's the difference between unit tests and integration tests?

Unit test is usually done for a single functionality implemented in Software module. The scope of testing is entirely within this SW module. Unit test never fulfils the final functional requirements. It comes under whitebox testing methodology..

Whereas Integration test is done to ensure the different SW module implementations. Testing is usually carried out after module level integration is done in SW development.. This test will cover the functional requirements but not enough to ensure system validation.

Check if item is in an array / list

You can also use the same syntax for an array. For example, searching within a Pandas series:

ser = pd.Series(['some', 'strings', 'to', 'query'])

if item in ser.values:
    # do stuff

Rails: Default sort order for a rails model?

default_scope

This works for Rails 4+:

class Book < ActiveRecord::Base
  default_scope { order(created_at: :desc) }
end

For Rails 2.3, 3, you need this instead:

default_scope order('created_at DESC')

For Rails 2.x:

default_scope :order => 'created_at DESC'

Where created_at is the field you want the default sorting to be done on.

Note: ASC is the code to use for Ascending and DESC is for descending (desc, NOT dsc !).

scope

Once you're used to that you can also use scope:

class Book < ActiveRecord::Base
  scope :confirmed, :conditions => { :confirmed => true }
  scope :published, :conditions => { :published => true }
end

For Rails 2 you need named_scope.

:published scope gives you Book.published instead of Book.find(:published => true).

Since Rails 3 you can 'chain' those methods together by concatenating them with periods between them, so with the above scopes you can now use Book.published.confirmed.

With this method, the query is not actually executed until actual results are needed (lazy evaluation), so 7 scopes could be chained together but only resulting in 1 actual database query, to avoid performance problems from executing 7 separate queries.

You can use a passed in parameter such as a date or a user_id (something that will change at run-time and so will need that 'lazy evaluation', with a lambda, like this:

scope :recent_books, lambda 
  { |since_when| where("created_at >= ?", since_when) }
  # Note the `where` is making use of AREL syntax added in Rails 3.

Finally you can disable default scope with:

Book.with_exclusive_scope { find(:all) } 

or even better:

Book.unscoped.all

which will disable any filter (conditions) or sort (order by).

Note that the first version works in Rails2+ whereas the second (unscoped) is only for Rails3+


So ... if you're thinking, hmm, so these are just like methods then..., yup, that's exactly what these scopes are!
They are like having def self.method_name ...code... end but as always with ruby they are nice little syntactical shortcuts (or 'sugar') to make things easier for you!

In fact they are Class level methods as they operate on the 1 set of 'all' records.

Their format is changing however, with rails 4 there are deprecation warning when using #scope without passing a callable object. For example scope :red, where(color: 'red') should be changed to scope :red, -> { where(color: 'red') }.

As a side note, when used incorrectly, default_scope can be misused/abused.
This is mainly about when it gets used for actions like where's limiting (filtering) the default selection (a bad idea for a default) rather than just being used for ordering results.
For where selections, just use the regular named scopes. and add that scope on in the query, e.g. Book.all.published where published is a named scope.

In conclusion, scopes are really great and help you to push things up into the model for a 'fat model thin controller' DRYer approach.

End of File (EOF) in C

That's a lot of questions.

  1. Why EOF is -1: usually -1 in POSIX system calls is returned on error, so i guess the idea is "EOF is kind of error"

  2. any boolean operation (including !=) returns 1 in case it's TRUE, and 0 in case it's FALSE, so getchar() != EOF is 0 when it's FALSE, meaning getchar() returned EOF.

  3. in order to emulate EOF when reading from stdin press Ctrl+D

Is there a foreach loop in Go?

This may be obvious, but you can inline the array like so:

package main

import (
    "fmt"
)

func main() {
    for _, element := range [3]string{"a", "b", "c"} {
        fmt.Print(element)
    }
}

outputs:

abc

https://play.golang.org/p/gkKgF3y5nmt

SSIS Convert Between Unicode and Non-Unicode Error

Instead of adding an earlier suggested Data Conversion you can cast the nvarchar column to a varchar column. This prevents you from having an unnecessary step and has a higher performance then the alternative.

In the select of your SQL statement replace date with CAST(date AS varchar([size])). For some reason this does not yet change the output data type. To do this do the following:

  1. Right click your OLE DB Source step and open the advanced editor.
  2. Go to Input and Output Properties
  3. Select Output Columns
  4. Select your column
  5. Under Data Type Properties change DataType to string [DT_STR]
  6. Change Length to the length you specified in your CAST statement

After doing this your source data will be output as a varchar and your error will disappear.

Source

Order a MySQL table by two columns

Default sorting is ascending, you need to add the keyword DESC to both your orders:

ORDER BY article_rating DESC, article_time DESC

Define an <img>'s src attribute in CSS

They are right. IMG is a content element and CSS is about design. But, how about when you use some content elements or properties for design purposes? I have IMG across my web pages that must change if i change the style (the CSS).

Well this is a solution for defining IMG presentation (no really the image) in CSS style.
1: create a 1x1 transparent gif or png.
2: Assign propery "src" of IMG to that image.
3: Define final presentation with "background-image" in the CSS style.

It works like a charm :)

Not equal to != and !== in PHP

You can find the info here: http://www.php.net/manual/en/language.operators.comparison.php

It's scarce because it wasn't added until PHP4. What you have is fine though, if you know there may be a type difference then it's a much better comparison, since it's testing value and type in the comparison, not just value.

error LNK2019: unresolved external symbol _WinMain@16 referenced in function ___tmainCRTStartup

Besides changing it to Console (/SUBSYSTEM:CONSOLE) as others have said, you may need to change the entry point in Properties -> Linker -> Advanced -> Entry Point. Set it to mainCRTStartup.

It seems that Visual Studio might be searching for the WinMain function instead of main, if you don't specify otherwise.

What does HTTP/1.1 302 mean exactly?

For anyone who might be curious about the naming, I'm just going to add that it's probably called "Found" because the main resource(e.g., a private web page) the user intends to receive is not available at that moment(e.g., the user has not proved their identity yet), so instead the server has found a new resource that the user can receive(which is a login page in the most common use case).

Also it's "getting lost and found" in the hide-and-seek manner, meaning a lost resource under a 302 status is only lost temporarily, it is not supposed to be lost forever(unless a player has some bad intentions;)).

Reset local repository branch to be just like remote repository HEAD

git reset --hard HEAD actually only resets to the last committed state. In this case HEAD refers to the HEAD of your branch.

If you have several commits, this won't work..

What you probably want to do, is reset to the head of origin or whatever you remote repository is called. I'd probably just do something like

git reset --hard origin/HEAD

Be careful though. Hard resets cannot easily be undone. It is better to do as Dan suggests, and branch off a copy of your changes before resetting.

Java Runtime.getRuntime(): getting output from executing a command line program

Pretty much the same as other snippets on this page but just organizing things up over an function, here we go...

String str=shell_exec("ls -l");

The Class function:

public String shell_exec(String cmd)
       {
       String o=null;
       try
         {
         Process p=Runtime.getRuntime().exec(cmd);
         BufferedReader b=new BufferedReader(new InputStreamReader(p.getInputStream()));
         String r;
         while((r=b.readLine())!=null)o+=r;
         }catch(Exception e){o="error";}
       return o;
       }

How to show only next line after the matched one?

you can try with awk:

awk '/blah/{getline; print}' logfile

CSS Animation onClick

You can achieve this by binding an onclick listener and then adding the animate class like this:

$('#button').onClick(function(){
    $('#target_element').addClass('animate_class_name');
});

Error "The connection to adb is down, and a severe error has occurred."

Open up the Windows task manager, kill the process named adb.exe, and re-launch your program.

MySQL error code: 1175 during UPDATE in MySQL Workbench

Since the question was answered and had nothing to do with safe updates, this might be the wrong place; I'll post just to add information.

I tried to be a good citizen and modified the query to use a temp table of ids that would get updated:

create temporary table ids ( id int )
    select id from prime_table where condition = true;
update prime_table set field1 = '' where id in (select id from ids);

Failure. Modified the update to:

update prime_table set field1 = '' where id <> 0 and id in (select id from ids);

That worked. Well golly -- if I am always adding where key <> 0 to get around the safe update check, or even set SQL_SAFE_UPDATE=0, then I've lost the 'check' on my query. I might as well just turn off the option permanently. I suppose it makes deleting and updating a two step process instead of one.. but if you type fast enough and stop thinking about the key being special but rather as just a nuisance..

How do I turn off PHP Notices?

I believe commenting out display_errors in php.ini won't work because the default is On. You must set it to 'Off' instead.

Don't forget to restart Apache to apply configuration changes.

Also note that while you can set display_errors at runtime, changing it here does not affect FATAL errors.

As noted by others, ideally during development you should run with error_reporting at the highest level possible and display_errors enabled. While annoying when you first start out, these errors, warnings, notices and strict coding advice all add up and enable you to becoem a better coder.

How to get thread id of a pthread in linux c program?

What? The person asked for Linux specific, and the equivalent of getpid(). Not BSD or Apple. The answer is gettid() and returns an integral type. You will have to call it using syscall(), like this:

#include <sys/types.h>
#include <unistd.h>
#include <sys/syscall.h>

 ....

 pid_t x = syscall(__NR_gettid);

While this may not be portable to non-linux systems, the threadid is directly comparable and very fast to acquire. It can be printed (such as for LOGs) like a normal integer.

Get child Node of another Node, given node name

Check if the Node is a Dom Element, cast, and call getElementsByTagName()

Node doc = docs.item(i);
if(doc instanceof Element) {
    Element docElement = (Element)doc;
    ...
    cell = doc.getElementsByTagName("aoo").item(0);
}

Read only the first line of a file?

Use the .readline() method (Python 2 docs, Python 3 docs):

with open('myfile.txt') as f:
    first_line = f.readline()

Some notes:

  1. As noted in the docs, unless it is the only line in the file, the string returned from f.readline() will contain a trailing newline. You may wish to use f.readline().strip() instead to remove the newline.
  2. The with statement automatically closes the file again when the block ends.
  3. The with statement only works in Python 2.5 and up, and in Python 2.5 you need to use from __future__ import with_statement
  4. In Python 3 you should specify the file encoding for the file you open. Read more...

How to implement the Android ActionBar back button?

Android Annotations:

@OptionsItem(android.R.id.home)
void homeSelected() {
    onBackPressed();
}

Source: https://github.com/excilys/androidannotations

Trim whitespace from a String

I think that substr() throws an exception if str only contains the whitespace.

I would modify it to the following code:

string trim(string& str)
{
    size_t first = str.find_first_not_of(' ');
    if (first == std::string::npos)
        return "";
    size_t last = str.find_last_not_of(' ');
    return str.substr(first, (last-first+1));
}

How to move div vertically down using CSS

I don't see any mention of flexbox in here, so I will illustrate:

HTML

 <div class="wrapper">
   <div class="main">top</div>
   <div class="footer">bottom</div>
 </div>

CSS

 .wrapper {
   display: flex;
   flex-direction: column;
   min-height: 100vh;
  }
 .main {
   flex: 1;
 }
 .footer {
  flex: 0;
 }

How do I delete all the duplicate records in a MySQL table without temp tables

Add Unique Index on your table:

ALTER IGNORE TABLE TableA   
ADD UNIQUE INDEX (member_id, quiz_num, question_num, answer_num);

is work very well

Calculating percentile of dataset column

table_ages <- subset(infert, select=c("age"))
summary(table_ages)
#            age       
#  Min.   :21.00  
#  1st Qu.:28.00  
#  Median :31.00  
#  Mean   :31.50  
#  3rd Qu.:35.25  
#  Max.   :44.00  

This is probably what they're looking for. summary(...) applied to a numeric returns the min, max, mean, median, and 25th and 75th percentile of the data.

Note that

summary(infert$age)
#    Min. 1st Qu.  Median    Mean 3rd Qu.    Max. 
#   21.00   28.00   31.00   31.50   35.25   44.00 

The numbers are the same but the format is different. This is because table_ages is a data frame with one column (ages), whereas infert$age is a numeric vector. Try typing summary(infert).

Pandas index column title or name

df.columns.values also give us the column names

How to get the first and last date of the current year?

SELECT
   DATEADD(yy, DATEDIFF(yy, 0, GETDATE()), 0) AS StartOfYear,
   DATEADD(yy, DATEDIFF(yy, 0, GETDATE()) + 1, -1) AS EndOfYear

The above query gives a datetime value for midnight at the beginning of December 31. This is about 24 hours short of the last moment of the year. If you want to include time that might occur on December 31, then you should compare to the first of the next year, with a < comparison. Or you can compare to the last few milliseconds of the current year, but this still leaves a gap if you are using something other than DATETIME (such as DATETIME2):

SELECT
   DATEADD(yy, DATEDIFF(yy, 0, GETDATE()), 0) AS StartOfYear,
   DATEADD(yy, DATEDIFF(yy, 0, GETDATE()) + 1, -1) AS LastDayOfYear,
   DATEADD(yy, DATEDIFF(yy, 0, GETDATE()) + 1, 0) AS FirstOfNextYear,
   DATEADD(ms, -3, DATEADD(yy, DATEDIFF(yy, 0, GETDATE()) + 1, 0)) AS LastTimeOfYear

Tech Details

This works by figuring out the number of years since 1900 with DATEDIFF(yy, 0, GETDATE()) and then adding that to a date of zero = Jan 1, 1900. This can be changed to work for an arbitrary date by replacing the GETDATE() portion or an arbitrary year by replacing the DATEDIFF(...) function with "Year - 1900."

 SELECT
   DATEADD(yy, DATEDIFF(yy, 0, '20150301'), 0) AS StartOfYearForMarch2015,
   DATEADD(yy, 2015 - 1900, 0) AS StartOfYearFor2015

what exactly is device pixel ratio?

Device Pixel Ratio == CSS Pixel Ratio

In the world of web development, the device pixel ratio (also called CSS Pixel Ratio) is what determines how a device's screen resolution is interpreted by the CSS.

A browser's CSS calculates a device's logical (or interpreted) resolution by the formula:

formula

For example:

Apple iPhone 6s

  • Actual Resolution: 750 x 1334
  • CSS Pixel Ratio: 2
  • Logical Resolution:

formula

When viewing a web page, the CSS will think the device has a 375x667 resolution screen and Media Queries will respond as if the screen is 375x667. But the rendered elements on the screen will be twice as sharp as an actual 375x667 screen because there are twice as many physical pixels in the physical screen.

Some other examples:

Samsung Galaxy S4

  • Actual Resolution: 1080 x 1920
  • CSS Pixel Ratio: 3
  • Logical Resolution:

formula

iPhone 5s

  • Actual Resolution: 640 x 1136
  • CSS Pixel Ratio: 2
  • Logical Resolution:

formula

Why does the Device Pixel Ratio exist?

The reason that CSS pixel ratio was created is because as phones screens get higher resolutions, if every device still had a CSS pixel ratio of 1 then webpages would render too small to see.

A typical full screen desktop monitor is a roughly 24" at 1920x1080 resolution. Imagine if that monitor was shrunk down to about 5" but had the same resolution. Viewing things on the screen would be impossible because they would be so small. But manufactures are coming out with 1920x1080 resolution phone screens consistently now.

So the device pixel ratio was invented by phone makers so that they could continue to push the resolution, sharpness and quality of phone screens, without making elements on the screen too small to see or read.

Here is a tool that also tells you your current device's pixel density:

http://bjango.com/articles/min-device-pixel-ratio/

Setting width to wrap_content for TextView through code

Solution for change TextView width to wrap content.

textView.getLayoutParams().width = ViewGroup.LayoutParams.WRAP_CONTENT; 
textView.requestLayout();  
// Call requestLayout() for redraw your TextView when your TextView is already drawn (laid out) (eg: you update TextView width when click a Button). 
// If your TextView is drawing you may not need requestLayout() (eg: you change TextView width inside onCreate()). However if you call it, it still working well => for easy: always use requestLayout()

// Another useful example
// textView.getLayoutParams().width = 200; // For change `TextView` width to 200 pixel

Creating random numbers with no duplicates

Generating all the indices of a sequence is generally a bad idea, as it might take a lot of time, especially if the ratio of the numbers to be chosen to MAX is low (the complexity becomes dominated by O(MAX)). This gets worse if the ratio of the numbers to be chosen to MAX approaches one, as then removing the chosen indices from the sequence of all also becomes expensive (we approach O(MAX^2/2)). But for small numbers, this generally works well and is not particularly error-prone.

Filtering the generated indices by using a collection is also a bad idea, as some time is spent in inserting the indices into the sequence, and progress is not guaranteed as the same random number can be drawn several times (but for large enough MAX it is unlikely). This could be close to complexity
O(k n log^2(n)/2), ignoring the duplicates and assuming the collection uses a tree for efficient lookup (but with a significant constant cost k of allocating the tree nodes and possibly having to rebalance).

Another option is to generate the random values uniquely from the beginning, guaranteeing progress is being made. That means in the first round, a random index in [0, MAX] is generated:

items i0 i1 i2 i3 i4 i5 i6 (total 7 items)
idx 0       ^^             (index 2)

In the second round, only [0, MAX - 1] is generated (as one item was already selected):

items i0 i1    i3 i4 i5 i6 (total 6 items)
idx 1          ^^          (index 2 out of these 6, but 3 out of the original 7)

The values of the indices then need to be adjusted: if the second index falls in the second half of the sequence (after the first index), it needs to be incremented to account for the gap. We can implement this as a loop, allowing us to select arbitrary number of unique items.

For short sequences, this is quite fast O(n^2/2) algorithm:

void RandomUniqueSequence(std::vector<int> &rand_num,
    const size_t n_select_num, const size_t n_item_num)
{
    assert(n_select_num <= n_item_num);

    rand_num.clear(); // !!

    // b1: 3187.000 msec (the fastest)
    // b2: 3734.000 msec
    for(size_t i = 0; i < n_select_num; ++ i) {
        int n = n_Rand(n_item_num - i - 1);
        // get a random number

        size_t n_where = i;
        for(size_t j = 0; j < i; ++ j) {
            if(n + j < rand_num[j]) {
                n_where = j;
                break;
            }
        }
        // see where it should be inserted

        rand_num.insert(rand_num.begin() + n_where, 1, n + n_where);
        // insert it in the list, maintain a sorted sequence
    }
    // tier 1 - use comparison with offset instead of increment
}

Where n_select_num is your 5 and n_number_num is your MAX. The n_Rand(x) returns random integers in [0, x] (inclusive). This can be made a bit faster if selecting a lot of items (e.g. not 5 but 500) by using binary search to find the insertion point. To do that, we need to make sure that we meet the requirements.

We will do binary search with the comparison n + j < rand_num[j] which is the same as
n < rand_num[j] - j. We need to show that rand_num[j] - j is still a sorted sequence for a sorted sequence rand_num[j]. This is fortunately easily shown, as the lowest distance between two elements of the original rand_num is one (the generated numbers are unique, so there is always difference of at least 1). At the same time, if we subtract the indices j from all the elements
rand_num[j], the differences in index are exactly 1. So in the "worst" case, we get a constant sequence - but never decreasing. The binary search can therefore be used, yielding O(n log(n)) algorithm:

struct TNeedle { // in the comparison operator we need to make clear which argument is the needle and which is already in the list; we do that using the type system.
    int n;

    TNeedle(int _n)
        :n(_n)
    {}
};

class CCompareWithOffset { // custom comparison "n < rand_num[j] - j"
protected:
    std::vector<int>::iterator m_p_begin_it;

public:
    CCompareWithOffset(std::vector<int>::iterator p_begin_it)
        :m_p_begin_it(p_begin_it)
    {}

    bool operator ()(const int &r_value, TNeedle n) const
    {
        size_t n_index = &r_value - &*m_p_begin_it;
        // calculate index in the array

        return r_value < n.n + n_index; // or r_value - n_index < n.n
    }

    bool operator ()(TNeedle n, const int &r_value) const
    {
        size_t n_index = &r_value - &*m_p_begin_it;
        // calculate index in the array

        return n.n + n_index < r_value; // or n.n < r_value - n_index
    }
};

And finally:

void RandomUniqueSequence(std::vector<int> &rand_num,
    const size_t n_select_num, const size_t n_item_num)
{
    assert(n_select_num <= n_item_num);

    rand_num.clear(); // !!

    // b1: 3578.000 msec
    // b2: 1703.000 msec (the fastest)
    for(size_t i = 0; i < n_select_num; ++ i) {
        int n = n_Rand(n_item_num - i - 1);
        // get a random number

        std::vector<int>::iterator p_where_it = std::upper_bound(rand_num.begin(), rand_num.end(),
            TNeedle(n), CCompareWithOffset(rand_num.begin()));
        // see where it should be inserted

        rand_num.insert(p_where_it, 1, n + p_where_it - rand_num.begin());
        // insert it in the list, maintain a sorted sequence
    }
    // tier 4 - use binary search
}

I have tested this on three benchmarks. First, 3 numbers were chosen out of 7 items, and a histogram of the items chosen was accumulated over 10,000 runs:

4265 4229 4351 4267 4267 4364 4257

This shows that each of the 7 items was chosen approximately the same number of times, and there is no apparent bias caused by the algorithm. All the sequences were also checked for correctness (uniqueness of contents).

The second benchmark involved choosing 7 numbers out of 5000 items. The time of several versions of the algorithm was accumulated over 10,000,000 runs. The results are denoted in comments in the code as b1. The simple version of the algorithm is slightly faster.

The third benchmark involved choosing 700 numbers out of 5000 items. The time of several versions of the algorithm was again accumulated, this time over 10,000 runs. The results are denoted in comments in the code as b2. The binary search version of the algorithm is now more than two times faster than the simple one.

The second method starts being faster for choosing more than cca 75 items on my machine (note that the complexity of either algorithm does not depend on the number of items, MAX).

It is worth mentioning that the above algorithms generate the random numbers in ascending order. But it would be simple to add another array to which the numbers would be saved in the order in which they were generated, and returning that instead (at negligible additional cost O(n)). It is not necessary to shuffle the output: that would be much slower.

Note that the sources are in C++, I don't have Java on my machine, but the concept should be clear.

EDIT:

For amusement, I have also implemented the approach that generates a list with all the indices
0 .. MAX, chooses them randomly and removes them from the list to guarantee uniqueness. Since I've chosen quite high MAX (5000), the performance is catastrophic:

// b1: 519515.000 msec
// b2: 20312.000 msec
std::vector<int> all_numbers(n_item_num);
std::iota(all_numbers.begin(), all_numbers.end(), 0);
// generate all the numbers

for(size_t i = 0; i < n_number_num; ++ i) {
    assert(all_numbers.size() == n_item_num - i);
    int n = n_Rand(n_item_num - i - 1);
    // get a random number

    rand_num.push_back(all_numbers[n]); // put it in the output list
    all_numbers.erase(all_numbers.begin() + n); // erase it from the input
}
// generate random numbers

I have also implemented the approach with a set (a C++ collection), which actually comes second on benchmark b2, being only about 50% slower than the approach with the binary search. That is understandable, as the set uses a binary tree, where the insertion cost is similar to binary search. The only difference is the chance of getting duplicate items, which slows down the progress.

// b1: 20250.000 msec
// b2: 2296.000 msec
std::set<int> numbers;
while(numbers.size() < n_number_num)
    numbers.insert(n_Rand(n_item_num - 1)); // might have duplicates here
// generate unique random numbers

rand_num.resize(numbers.size());
std::copy(numbers.begin(), numbers.end(), rand_num.begin());
// copy the numbers from a set to a vector

Full source code is here.

How can I quantify difference between two images?

I have been having a lot of luck with jpg images taken with the same camera on a tripod by (1) simplifying greatly (like going from 3000 pixels wide to 100 pixels wide or even fewer) (2) flattening each jpg array into a single vector (3) pairwise correlating sequential images with a simple correlate algorithm to get correlation coefficient (4) squaring correlation coefficient to get r-square (i.e fraction of variability in one image explained by variation in the next) (5) generally in my application if r-square < 0.9, I say the two images are different and something happened in between.

This is robust and fast in my implementation (Mathematica 7)

It's worth playing around with the part of the image you are interested in and focussing on that by cropping all images to that little area, otherwise a distant-from-the-camera but important change will be missed.

I don't know how to use Python, but am sure it does correlations, too, no?

How to avoid warning when introducing NAs by coercion

I have slightly modified the jangorecki function for the case where we may have a variety of values that cannot be converted to a number. In my function, a template search is performed and if the template is not found, FALSE is returned.! before gperl, it means that we need those vector elements that do not match the template. The rest is similar to the as.num function. Example:

as.num.pattern <- function(x, pattern){
  stopifnot(is.character(x))
  na = !grepl(pattern, x)
  x[na] = -Inf
  x = as.numeric(x)
  x[na] = NA_real_
  x
}

as.num.pattern(c('1', '2', '3.43', 'char1', 'test2', 'other3', '23/40', '23, 54 cm.'))

[1] 1.00 2.00 3.43   NA   NA   NA   NA   NA

What is the strict aliasing rule?

A typical situation where you encounter strict aliasing problems is when overlaying a struct (like a device/network msg) onto a buffer of the word size of your system (like a pointer to uint32_ts or uint16_ts). When you overlay a struct onto such a buffer, or a buffer onto such a struct through pointer casting you can easily violate strict aliasing rules.

So in this kind of setup, if I want to send a message to something I'd have to have two incompatible pointers pointing to the same chunk of memory. I might then naively code something like this:

typedef struct Msg
{
    unsigned int a;
    unsigned int b;
} Msg;

void SendWord(uint32_t);

int main(void)
{
    // Get a 32-bit buffer from the system
    uint32_t* buff = malloc(sizeof(Msg));
    
    // Alias that buffer through message
    Msg* msg = (Msg*)(buff);
    
    // Send a bunch of messages    
    for (int i = 0; i < 10; ++i)
    {
        msg->a = i;
        msg->b = i+1;
        SendWord(buff[0]);
        SendWord(buff[1]);   
    }
}

The strict aliasing rule makes this setup illegal: dereferencing a pointer that aliases an object that is not of a compatible type or one of the other types allowed by C 2011 6.5 paragraph 71 is undefined behavior. Unfortunately, you can still code this way, maybe get some warnings, have it compile fine, only to have weird unexpected behavior when you run the code.

(GCC appears somewhat inconsistent in its ability to give aliasing warnings, sometimes giving us a friendly warning and sometimes not.)

To see why this behavior is undefined, we have to think about what the strict aliasing rule buys the compiler. Basically, with this rule, it doesn't have to think about inserting instructions to refresh the contents of buff every run of the loop. Instead, when optimizing, with some annoyingly unenforced assumptions about aliasing, it can omit those instructions, load buff[0] and buff[1] into CPU registers once before the loop is run, and speed up the body of the loop. Before strict aliasing was introduced, the compiler had to live in a state of paranoia that the contents of buff could change by any preceding memory stores. So to get an extra performance edge, and assuming most people don't type-pun pointers, the strict aliasing rule was introduced.

Keep in mind, if you think the example is contrived, this might even happen if you're passing a buffer to another function doing the sending for you, if instead you have.

void SendMessage(uint32_t* buff, size_t size32)
{
    for (int i = 0; i < size32; ++i) 
    {
        SendWord(buff[i]);
    }
}

And rewrote our earlier loop to take advantage of this convenient function

for (int i = 0; i < 10; ++i)
{
    msg->a = i;
    msg->b = i+1;
    SendMessage(buff, 2);
}

The compiler may or may not be able to or smart enough to try to inline SendMessage and it may or may not decide to load or not load buff again. If SendMessage is part of another API that's compiled separately, it probably has instructions to load buff's contents. Then again, maybe you're in C++ and this is some templated header only implementation that the compiler thinks it can inline. Or maybe it's just something you wrote in your .c file for your own convenience. Anyway undefined behavior might still ensue. Even when we know some of what's happening under the hood, it's still a violation of the rule so no well defined behavior is guaranteed. So just by wrapping in a function that takes our word delimited buffer doesn't necessarily help.

So how do I get around this?

  • Use a union. Most compilers support this without complaining about strict aliasing. This is allowed in C99 and explicitly allowed in C11.

      union {
          Msg msg;
          unsigned int asBuffer[sizeof(Msg)/sizeof(unsigned int)];
      };
    
  • You can disable strict aliasing in your compiler (f[no-]strict-aliasing in gcc))

  • You can use char* for aliasing instead of your system's word. The rules allow an exception for char* (including signed char and unsigned char). It's always assumed that char* aliases other types. However this won't work the other way: there's no assumption that your struct aliases a buffer of chars.

Beginner beware

This is only one potential minefield when overlaying two types onto each other. You should also learn about endianness, word alignment, and how to deal with alignment issues through packing structs correctly.

Footnote

1 The types that C 2011 6.5 7 allows an lvalue to access are:

  • a type compatible with the effective type of the object,
  • a qualified version of a type compatible with the effective type of the object,
  • a type that is the signed or unsigned type corresponding to the effective type of the object,
  • a type that is the signed or unsigned type corresponding to a qualified version of the effective type of the object,
  • an aggregate or union type that includes one of the aforementioned types among its members (including, recursively, a member of a subaggregate or contained union), or
  • a character type.

What's the difference between .NET Core, .NET Framework, and Xamarin?

.NET 5 will be a unified version of all .NET variants coming in November 2020, so there will be no need to choose between variants anymore. enter image description here

React Checkbox not sending onChange

To get the checked state of your checkbox the path would be:

this.refs.complete.state.checked

The alternative is to get it from the event passed into the handleChange method:

event.target.checked

Accessing a resource via codebehind in WPF

You may also use this.Resources["mykey"]. I guess that is not much better than your own suggestion.

LabelEncoder: TypeError: '>' not supported between instances of 'float' and 'str'

As string data types have variable length, it is by default stored as object type. I faced this problem after treating missing values too. Converting all those columns to type 'category' before label encoding worked in my case.

df[cat]=df[cat].astype('category')

And then check df.dtypes and perform label encoding.

Are complex expressions possible in ng-hide / ng-show?

Use a controller method if you need to run arbitrary JavaScript code, or you could define a filter that returned true or false.

I just tested (should have done that first), and something like ng-show="!a && b" worked as expected.

No module named 'pymysql'

If even sudo apt-get install python3-pymysql does not work for you try this:

  • Go to the PyMySQL page and download the zip file.
  • Then, via the terminal, cd to your Downloads folder and extract the folder
  • cd into the newly extracted folder
  • Install the setup.py file with: sudo python3 setup.py install

Comparing boxed Long values 127 and 128

num1 and num2 are Long objects. You should be using equals() to compare them. == comparison might work sometimes because of the way JVM boxes primitives, but don't depend on it.

if (num1.equals(num1))
{
 //code
}

How do I convert an existing callback API to promises?

es6-promisify converts callback-based functions to Promise-based functions.

const promisify = require('es6-promisify');

const promisedFn = promisify(callbackedFn, args);

Ref: https://www.npmjs.com/package/es6-promisify

source command not found in sh shell

This problem happens because jenkins Execute Shell runs the script via its /bin/sh

Consequently, /bin/sh does not know "source"

You just need to add the below line at the top of your Execute Shell in jenkins

#!/bin/bash

What is the iBeacon Bluetooth Profile

It’s very simple, it just advertises a string which contains a few characters conforming to Apple’s iBeacon standard. you can refer the Link http://glimwormbeacons.com/learn/what-makes-an-ibeacon-an-ibeacon/

Show row number in row header of a DataGridView

You can also draw the string dynamically inside the RowPostPaint event:

private void dgGrid_RowPostPaint(object sender, DataGridViewRowPostPaintEventArgs e)
{
    var grid = sender as DataGridView;
    var rowIdx = (e.RowIndex + 1).ToString();

    var centerFormat = new StringFormat() 
    { 
        // right alignment might actually make more sense for numbers
        Alignment = StringAlignment.Center, 
        LineAlignment = StringAlignment.Center
    };

    var headerBounds = new Rectangle(e.RowBounds.Left, e.RowBounds.Top, grid.RowHeadersWidth, e.RowBounds.Height);
    e.Graphics.DrawString(rowIdx, this.Font, SystemBrushes.ControlText, headerBounds, centerFormat);
}

What does `ValueError: cannot reindex from a duplicate axis` mean?

Simply skip the error using .values at the end.

affinity_matrix.loc['sums'] = affinity_matrix.sum(axis=0).values

Relative path to absolute path in C#?

This worked.

var s = Path.Combine(@"C:\some\location", @"..\other\file.txt");
s = Path.GetFullPath(s);

Upload artifacts to Nexus, without Maven

If you need a convenient command line interface or python API, look at repositorytools

Using it, you can upload artifact to nexus with command

artifact upload foo-1.2.3.ext releases com.fooware

To make it work, you will also need to set some environment variables

export REPOSITORY_URL=https://repo.example.com
export REPOSITORY_USER=admin
export REPOSITORY_PASSWORD=mysecretpassword

How to check if div element is empty

if ($("#cartContent").children().length == 0) 
{
     // no child
}

IntelliJ does not show 'Class' when we right click and select 'New'

Most of the people already gave the answer but this one is just for making someone's life easier.

TL;DR

Screenshot of how to add test sources

You must add the test folder as source.

  1. Right click on java directory under test
  2. Mark it as Tests
  3. Add src/test/java in Test Source Folders

Thats it, IntelliJ will consider them as test source.

Progress Bar with HTML and CSS

Why can't you just Create Multiple pictures for each part of the status bar? If it's a third just show a third of the status bar... it's very simple. You could probably figure out how to change it to the next picture based of input with the form tag. Here's my part of the code, you have to figure out the form stuff later

<form> <!--(extra code)-->
<!--first progress bar:-->
<img src="directory"></img>
<!--second progress bar:-->
<img src="directory"></img>
<!--et caetera...-->
</form>

Now it seems simple, doesn't it?

Run a .bat file using python code

This has already been answered in detail on SO. Check out this thread, It should answer all your questions: Executing a subprocess fails

I've tried it myself with this code:

batchtest.py

from subprocess import Popen
p = Popen("batch.bat", cwd=r"C:\Path\to\batchfolder")
stdout, stderr = p.communicate()

batch.bat

echo Hello World!
pause

I've got the batchtest.py example from the aforementioned thread.

How to ssh from within a bash script?

If you want to continue to use passwords and not use key exchange then you can accomplish this with 'expect' like so:

#!/usr/bin/expect -f
spawn ssh user@hostname
expect "password:"
sleep 1
send "<your password>\r"
command1
command2
commandN

Hidden Features of Xcode

When typing a method press ESC to see the code completion options (no doubt this has been mentioned before). I already knew about this, but TODAY I discovered that if you press the button in the lower-right-hand corner of the code completion window (it'll be either an 'A' or Pi) you can toggle between alphabetical sorting and what appears to be sorting by class hierarchy.

All of a sudden this window is useful!

Ruby sleep or delay less than a second?

sleep(1.0/24.0)

As to your follow up question if that's the best way: No, you could get not-so-smooth framerates because the rendering of each frame might not take the same amount of time.

You could try one of these solutions:

  • Use a timer which fires 24 times a second with the drawing code.
  • Create as many frames as possible, create the motion based on the time passed, not per frame.

How to resolve symbolic links in a shell script

Common shell scripts often have to find their "home" directory even if they are invoked as a symlink. The script thus have to find their "real" position from just $0.

cat `mvn`

on my system prints a script containing the following, which should be a good hint at what you need.

if [ -z "$M2_HOME" ] ; then
  ## resolve links - $0 may be a link to maven's home
  PRG="$0"

  # need this for relative symlinks
  while [ -h "$PRG" ] ; do
    ls=`ls -ld "$PRG"`
    link=`expr "$ls" : '.*-> \(.*\)$'`
    if expr "$link" : '/.*' > /dev/null; then
      PRG="$link"
    else
      PRG="`dirname "$PRG"`/$link"
    fi
  done

  saveddir=`pwd`

  M2_HOME=`dirname "$PRG"`/..

  # make it fully qualified
  M2_HOME=`cd "$M2_HOME" && pwd`

ng if with angular for string contains

Only the shortcut syntax worked for me *ngIf.

(I think it's the later versions that use this syntax if I'm not mistaken)

<div *ngIf="haystack.indexOf('needle') > -1">
</div>

or

<div *ngIf="haystack.includes('needle')">
</div>

Get the real width and height of an image with JavaScript? (in Safari/Chrome)

this works for me (safari 3.2), by firing from within the window.onload event:

$(window).load(function() {
  var pic = $('img');

  pic.removeAttr("width"); 
  pic.removeAttr("height");

  alert( pic.width() );
  alert( pic.height() );
});

Laravel 5 PDOException Could Not Find Driver

I'm using Ubuntu 16.04 and PHP 5.6.20

After too many problems, the below steps solved this for me:

  1. find php.ini path via phpinfo()

  2. uncomment

    extension=php_pdo_mysql.dll
    
  3. add this line

    extension=pdo_mysql.so
    
  4. then run

    sudo apt-get install php-mysql
    

git ignore vim temporary files

Vim temporary files end with ~ so you can add to the file .gitignore the line

*~

Vim also creates swap files that have the swp and swo extensions. to remove those use the lines:

*.swp
*.swo

This will ignore all the vim temporary files in a single project

If you want to do it globally, you can create a .gitignore file in your home (you can give it other name or location), and use the following command:

git config --global core.excludesfile ~/.gitignore

Then you just need to add the files you want to ignore to that file

JavaScript unit test tools for TDD

You have "runs on actual browser" as a pro, but in my experience that is a con because it is slow. But what makes it valuable is the lack of sufficient JS emulation from the non-browser alternatives. It could be that if your JS is complex enough that only an in browser test will suffice, but there are a couple more options to consider:

HtmlUnit: "It has fairly good JavaScript support (which is constantly improving) and is able to work even with quite complex AJAX libraries, simulating either Firefox or Internet Explorer depending on the configuration you want to use." If its emulation is good enough for your use then it will be much faster than driving a browser.

But maybe HtmlUnit has good enough JS support but you don't like Java? Then maybe:

Celerity: Watir API running on JRuby backed by HtmlUnit.

or similarly

Schnell: another JRuby wrapper of HtmlUnit.

Of course if HtmlUnit isn't good enough and you have to drive a browser then you might consider Watir to drive your JS.

CSS: how to position element in lower right?

Lets say your HTML looks something like this:

<div class="box">
    <!-- stuff -->
    <p class="bet_time">Bet 5 days ago</p>
</div>

Then, with CSS, you can make that text appear in the bottom right like so:

.box {
    position:relative;
}
.bet_time {
    position:absolute;
    bottom:0;
    right:0;
}

The way this works is that absolutely positioned elements are always positioned with respect to the first relatively positioned parent element, or the window. Because we set the box's position to relative, .bet_time positions its right edge to the right edge of .box and its bottom edge to the bottom edge of .box

How to initialize all members of an array to the same value?

If your compiler is GCC you can use following syntax:

int array[1024] = {[0 ... 1023] = 5};

Check out detailed description: http://gcc.gnu.org/onlinedocs/gcc-4.1.2/gcc/Designated-Inits.html

Remove scrollbars from textarea

Hide scroll bar, but while still being able to scroll using CSS

To hide the scrollbar use -webkit- because it is supported by major browsers (Google Chrome, Safari or newer versions of Opera). There are many other options for the other browsers which are listed below:

    -webkit- (Chrome, Safari, newer versions of Opera):
    .element::-webkit-scrollbar { width: 0 !important }
    -moz- (Firefox):
    .element { overflow: -moz-scrollbars-none; }
    -ms- (Internet Explorer +10):
    .element { -ms-overflow-style: none; }

ref: https://www.geeksforgeeks.org/hide-scroll-bar-but-while-still-being-able-to-scroll-using-css/

Using OR in SQLAlchemy

SQLAlchemy overloads the bitwise operators &, | and ~ so instead of the ugly and hard-to-read prefix syntax with or_() and and_() (like in Bastien's answer) you can use these operators:

.filter((AddressBook.lastname == 'bulger') | (AddressBook.firstname == 'whitey'))

Note that the parentheses are not optional due to the precedence of the bitwise operators.

So your whole query could look like this:

addr = session.query(AddressBook) \
    .filter(AddressBook.city == "boston") \
    .filter((AddressBook.lastname == 'bulger') | (AddressBook.firstname == 'whitey'))

What does the Java assert keyword do, and when should it be used?

In addition to all the great answers provided here, the official Java SE 7 programming guide has a pretty concise manual on using assert; with several spot-on examples of when it's a good (and, importantly, bad) idea to use assertions, and how it's different from throwing exceptions.

Link

How to convert Blob to File in JavaScript

This function converts a Blob into a File and it works great for me.

Vanilla JavaScript

function blobToFile(theBlob, fileName){
    //A Blob() is almost a File() - it's just missing the two properties below which we will add
    theBlob.lastModifiedDate = new Date();
    theBlob.name = fileName;
    return theBlob;
}

TypeScript (with proper typings)

public blobToFile = (theBlob: Blob, fileName:string): File => {
    var b: any = theBlob;
    //A Blob() is almost a File() - it's just missing the two properties below which we will add
    b.lastModifiedDate = new Date();
    b.name = fileName;

    //Cast to a File() type
    return <File>theBlob;
}

Usage

var myBlob = new Blob();

//do stuff here to give the blob some data...

var myFile = blobToFile(myBlob, "my-image.png");

The program can't start because cygwin1.dll is missing... in Eclipse CDT

You can compile with either Cygwin's g++ or MinGW (via stand-alone or using Cygwin package). However, in order to run it, you need to add the Cygwin1.dll (and others) PATH to the system Windows PATH, before any cygwin style paths.

Thus add: ;C:\cygwin64\bin to the end of your Windows system PATH variable.

Also, to compile for use in CMD or PowerShell, you may need to use:

x86_64-w64-mingw32-g++.exe -static -std=c++11 prog_name.cc -o prog_name.exe

(This invokes the cross-compiler, if installed.)

Using ConfigurationManager to load config from an arbitrary location

For ASP.NET use WebConfigurationManager:

var config = WebConfigurationManager.OpenWebConfiguration("~/Sites/" + requestDomain + "/");
(..)
config.AppSettings.Settings["xxxx"].Value;

How can I copy a Python string?

To put it a different way "id()" is not what you care about. You want to know if the variable name can be modified without harming the source variable name.

>>> a = 'hello'                                                                                                                                                                                                                                                                                        
>>> b = a[:]                                                                                                                                                                                                                                                                                           
>>> c = a                                                                                                                                                                                                                                                                                              
>>> b += ' world'                                                                                                                                                                                                                                                                                      
>>> c += ', bye'                                                                                                                                                                                                                                                                                       
>>> a                                                                                                                                                                                                                                                                                                  
'hello'                                                                                                                                                                                                                                                                                                
>>> b                                                                                                                                                                                                                                                                                                  
'hello world'                                                                                                                                                                                                                                                                                          
>>> c                                                                                                                                                                                                                                                                                                  
'hello, bye'                                                                                                                                                                                                                                                                                           

If you're used to C, then these are like pointer variables except you can't de-reference them to modify what they point at, but id() will tell you where they currently point.

The problem for python programmers comes when you consider deeper structures like lists or dicts:

>>> o={'a': 10}                                                                                                                                                                                                                                                                                        
>>> x=o                                                                                                                                                                                                                                                                                                
>>> y=o.copy()                                                                                                                                                                                                                                                                                         
>>> x['a'] = 20                                                                                                                                                                                                                                                                                        
>>> y['a'] = 30                                                                                                                                                                                                                                                                                        
>>> o                                                                                                                                                                                                                                                                                                  
{'a': 20}                                                                                                                                                                                                                                                                                              
>>> x                                                                                                                                                                                                                                                                                                  
{'a': 20}                                                                                                                                                                                                                                                                                              
>>> y                                                                                                                                                                                                                                                                                                  
{'a': 30}                                                                                                                                                                                                                                                                                              

Here o and x refer to the same dict o['a'] and x['a'], and that dict is "mutable" in the sense that you can change the value for key 'a'. That's why "y" needs to be a copy and y['a'] can refer to something else.

String concatenation in Ruby

The + operator is the normal concatenation choice, and is probably the fastest way to concatenate strings.

The difference between + and << is that << changes the object on its left hand side, and + doesn't.

irb(main):001:0> s = 'a'
=> "a"
irb(main):002:0> s + 'b'
=> "ab"
irb(main):003:0> s
=> "a"
irb(main):004:0> s << 'b'
=> "ab"
irb(main):005:0> s
=> "ab"

Recover unsaved SQL query scripts

I use the free file searching program Everything, search for *.sql files across my C: drive, and then sort by Last Modified, and then browse by the date I think it was probably last executed.

It usually brings up loads of autorecovery files from a variety of locations. And you don't have to worry where the latest version of SSMS/VS is saving the backup files this version.

enter image description here

Count number of tables in Oracle

If you want to know the number of tables that belong to a certain schema/user, you can also use SQL similar to this one:

SELECT Count(*) FROM DBA_TABLES where OWNER like 'PART_OF_NAME%';

Android Studio: Add jar as library?

You can do this with two options.

first simple way.

Copy the .jar file to clipboard then add it to libs folder. To see libs folder in the project, choose the project from combobox above the folders.

then right click on the .jar file and click add as a library then choose a module then ok. You can see the .jar file in build.gradle file within dependencies block.

 dependencies {
        implementation fileTree(dir: 'libs', include: ['*.jar'])
        implementation 'com.android.support:appcompat-v7:21.0.3'
        implementation project(':okhttp-2.0.0')
        implementation 'com.google.code.gson:gson:2.3.1'
    }

Second way is that: We can add a .jar file to a module by importing this .jar file as a .jar module then add this module to any module we want.

import module ---> choose your .jar file --> than import as a .jar -- enter image description here

Then CTRL+ALT+SHIFT+S --> project sturure -->choose the module you want ato add a jar -->Dependencendies --> Module Dependency. build.gradle of the module will updated automatically. enter image description here

Simpler way to check if variable is not equal to multiple string values?

For your first code, you can use a short alteration of the answer given by @ShankarDamodaran using in_array():

if ( !in_array($some_variable, array('uk','in'), true ) ) {

or even shorter with [] notation available since php 5.4 as pointed out by @Forty in the comments

if ( !in_array($some_variable, ['uk','in'], true ) ) {

is the same as:

if ( $some_variable !== 'uk' && $some_variable !== 'in' ) {

... but shorter. Especially if you compare more than just 'uk' and 'in'. I do not use an additional variable (Shankar used $os) but instead define the array in the if statement. Some might find that dirty, i find it quick and neat :D

The problem with your second code is that it can easily be exchanged with just TRUE since:

if (true) {

equals

if ( $some_variable !== 'uk' || $some_variable !== 'in' ) {

You are asking if the value of a string is not A or Not B. If it is A, it is definitely not also B and if it is B it is definitely not A. And if it is C or literally anything else, it is also not A and not B. So that statement always (not taking into account schrödingers law here) returns true.

How to echo xml file in php

The best solution is to add to your apache .htaccess file the following line after RewriteEngine On

RewriteRule ^sitemap\.xml$ sitemap.php [L]

and then simply having a file sitemap.php in your root folder that would be normally accessible via http://www.yoursite.com/sitemap.xml, the default URL where all search engines will firstly search.

The file sitemap.php shall start with

<?php
//Saturday, 11 January 2020 @kevin

header('Content-type: text/xml');
echo '<?xml version="1.0" encoding="UTF-8"?>';
?>
<urlset
      xmlns="http://www.sitemaps.org/schemas/sitemap/0.9"
      xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
      xsi:schemaLocation="http://www.sitemaps.org/schemas/sitemap/0.9
            http://www.sitemaps.org/schemas/sitemap/0.9/sitemap.xsd">

<url>
  <loc>https://www.yoursite.com/</loc>
  <lastmod>2020-01-08T13:06:14+00:00</lastmod>
  <priority>1.00</priority>
</url>


</urlset>

it works :)

Difference between .dll and .exe?

I don't know why everybody is answering this question in context of .NET. The question was a general one and didn't mention .NET anywhere.

Well, the major differences are:

EXE

  1. An exe always runs in its own address space i.e., It is a separate process.
  2. The purpose of an EXE is to launch a separate application of its own.

DLL

  1. A dll always needs a host exe to run. i.e., it can never run in its own address space.
  2. The purpose of a DLL is to have a collection of methods/classes which can be re-used from some other application.
  3. DLL is Microsoft's implementation of a shared library.

The file format of DLL and exe is essentially the same. Windows recognizes the difference between DLL and EXE through PE Header in the file. For details of PE Header, You can have a look at this Article on MSDN

iOS 7 status bar overlapping UI

If your developing for iOS 7 I wouldn't recommend wrapping the status bar in a black rectangle old iOS style. Just integrate it to the design for a more iOS 7 "fullscreen" look.

You can use this plugin to adjust the ink colour of the status bar, or hide it or show it in any instance of your app.

https://github.com/jota-v/cordova-ios-statusbar

The js methods are:

window.plugins.statusBar.hide();
window.plugins.statusBar.show();
window.plugins.statusBar.blackTint();
window.plugins.statusBar.whiteTint();

IMPORTANT: Also in your app plist file set UIViewControllerBasedStatusBarAppearance to NO.

How to normalize a 2-dimensional numpy array in python less verbose?

Here is one more possible way using reshape:

a_norm = (a/a.sum(axis=1).reshape(-1,1)).round(3)
print(a_norm)

Or using None works too:

a_norm = (a/a.sum(axis=1)[:,None]).round(3)
print(a_norm)

Output:

array([[0.   , 0.333, 0.667],
       [0.25 , 0.333, 0.417],
       [0.286, 0.333, 0.381]])

Editing an item in a list<T>

You don't need to use linq since List<T> provides the methods to do this:

int index = lst.FindLastIndex(c => c.Number == textBox6.Text);
if(index != -1)
{
    lst[index] = new Class1() { ... };
}

How to fix a locale setting warning from Perl

For anyone connecting to DigitalOcean or some other Cloud hosting provider from the iTerm2.app on macOS v10.13 (High Sierra) and getting this error on some commands:

perl: warning: Setting locale failed.
perl: warning: Please check that your locale settings:
    LANGUAGE = (unset),
    LC_ALL = (unset),
    LC_CTYPE = "UTF-8",
    LANG = "en_US.UTF-8"
  are supported and installed on your system.
perl: warning: Falling back to a fallback locale ("en_US.UTF-8").

This fixed the problem for me:

Enter image description here

@UniqueConstraint and @Column(unique = true) in hibernate annotation

As said before, @Column(unique = true) is a shortcut to UniqueConstraint when it is only a single field.

From the example you gave, there is a huge difference between both.

@Column(unique = true)
@ManyToOne(optional = false, fetch = FetchType.EAGER)
private ProductSerialMask mask;

@Column(unique = true)
@ManyToOne(optional = false, fetch = FetchType.EAGER)
private Group group;

This code implies that both mask and group have to be unique, but separately. That means that if, for example, you have a record with a mask.id = 1 and tries to insert another record with mask.id = 1, you'll get an error, because that column should have unique values. The same aplies for group.

On the other hand,

@Table(
   name = "product_serial_group_mask", 
   uniqueConstraints = {@UniqueConstraint(columnNames = {"mask", "group"})}
)

Implies that the values of mask + group combined should be unique. That means you can have, for example, a record with mask.id = 1 and group.id = 1, and if you try to insert another record with mask.id = 1 and group.id = 2, it'll be inserted successfully, whereas in the first case it wouldn't.

If you'd like to have both mask and group to be unique separately and to that at class level, you'd have to write the code as following:

@Table(
        name = "product_serial_group_mask",
        uniqueConstraints = {
                @UniqueConstraint(columnNames = "mask"),
                @UniqueConstraint(columnNames = "group")
        }
)

This has the same effect as the first code block.

Changing default startup directory for command prompt in Windows 7

  1. go to regedit ( go to search and type regedit)
  2. expand "HKEY_CURRENT_USER" node
  3. under HKEY_CURRENT_USER node expand "software" node
  4. under software node expand "microsoft" node
  5. under microsoft node click on "Command Processor"
  6. path looks like this : "HKEY_CURRENT_USER\Software\Microsoft\Command Processor"

it looks something like this :

  1. if you do not see "Autorun" String Value
  2. Right Click - New - Expandable String Value, and rename it to Autorun
  3. double click on "Autorun" 10.enter this value path format:
  4. "CD/d C:\yourfoldername\yoursubfoldername"

What does 'public static void' mean in Java?

Public - means that the class (program) is available for use by any other class.

Static - creates a class. Can also be applied to variables and methods,making them class methods/variables instead of just local to a particular instance of the class.

Void - this means that no product is returned when the class completes processing. Compare this with helper classes that provide a return value to the main class,these operate like functions; these do not have void in the declaration.

How to check if an object is defined?

If a class type is not defined, you'll get a compiler error if you try to use the class, so in that sense you should have to check.

If you have an instance, and you want to ensure it's not null, simply check for null:

if (value != null)
{
    // it's not null. 
}

Adding minutes to date time in PHP

As noted by Brad and Nemoden in their answers above, strtotime() is a great function. Personally, I found the standard DateTime Object to be overly complicated for many use cases. I just wanted to add 5 minutes to the current time, for example.

I wrote a function that returns a date as a string with some optional parameters:
1.) time:String | ex: "+5 minutes" (default = current time)
2.) format:String | ex: "Y-m-d H:i:s" (default = "Y-m-d H:i:s O")

Obviously, this is not a fully featured method. Just a quick and simple function for modifying/formatting the current date.

function get_date($time=null, $format='Y-m-d H:i:s O')
{
    if(empty($time))return date($format);
    return date($format, strtotime($time));
}

// Example #1: Return current date in default format
$date = get_date(); 

// Example #2: Add 5 minutes to the current date
$date = get_date("+5 minutes"); 

// Example #3: Subtract 30 days from the current date & format as 'Y-m-d H:i:s'
$date = get_date("-30 days", "Y-m-d H:i:s"); 

Convert a Unix timestamp to time in JavaScript

_x000D_
_x000D_
let unix_timestamp = 1549312452_x000D_
// Create a new JavaScript Date object based on the timestamp_x000D_
// multiplied by 1000 so that the argument is in milliseconds, not seconds._x000D_
var date = new Date(unix_timestamp * 1000);_x000D_
// Hours part from the timestamp_x000D_
var hours = date.getHours();_x000D_
// Minutes part from the timestamp_x000D_
var minutes = "0" + date.getMinutes();_x000D_
// Seconds part from the timestamp_x000D_
var seconds = "0" + date.getSeconds();_x000D_
_x000D_
// Will display time in 10:30:23 format_x000D_
var formattedTime = hours + ':' + minutes.substr(-2) + ':' + seconds.substr(-2);_x000D_
_x000D_
console.log(formattedTime);
_x000D_
_x000D_
_x000D_

For more information regarding the Date object, please refer to MDN or the ECMAScript 5 specification.

Correct Way to Load Assembly, Find Class and Call Run() Method

You will need to use reflection to get the type "TestRunner". Use the Assembly.GetType method.

class Program
{
    static void Main(string[] args)
    {
        Assembly assembly = Assembly.LoadFile(@"C:\dyn.dll");
        Type type = assembly.GetType("TestRunner");
        var obj = (TestRunner)Activator.CreateInstance(type);
        obj.Run();
    }
}

Flatten an irregular list of lists

def nested_list(depth):
    l = [depth]
    for i in range(depth-1, 0, -1):
        l = [i, l]
    return l

nested_list(10)

[1, [2, [3, [4, [5, [6, [7, [8, [9, [10]]]]]]]]]]

def Flatten(ul):
    fl = []
    for i in ul:
        if type(i) is list:
            fl += Flatten(i)
        else:
            fl += [i]
    return fl

Flatten(nested_list(10))

[1, 2, 3, 4, 5, 6, 7, 8, 9, 10]

Benchmarking

l = nested_list(100)

https://stackoverflow.com/a/2158532

import collections

def flatten(l):
    for el in l:
        if isinstance(el, collections.Iterable) and not isinstance(el, (str, bytes)):
            yield from flatten(el)
        else:
            yield el
%%timeit -n 1000
list(flatten(l))

320 µs ± 14.3 µs per loop (mean ± std. dev. of 7 runs, 1000 loops each)

%%timeit -n 1000
Flatten(l)

60 µs ± 10.2 µs per loop (mean ± std. dev. of 7 runs, 1000 loops each)

list(flatten(l)) == Flatten(l)

True

How to truncate the time on a DateTime object in Python?

You can use datetime.strftime to extract the day, the month, the year...

Example :

from datetime import datetime
d = datetime.today()

# Retrieves the day and the year
print d.strftime("%d-%Y")

Output (for today):

29-2011

If you just want to retrieve the day, you can use day attribute like :

from datetime import datetime
d = datetime.today()

# Retrieves the day
print d.day

Ouput (for today):

29

parse html string with jquery

One thing to note - as I had exactly this problem today, depending on your HTML jQuery may or may not parse it that well. jQuery wouldn't parse my HTML into a correct DOM - on smaller XML compliant files it worked fine, but the HTML I had (that would render in a page) wouldn't parse when passed back to an Ajax callback.

In the end I simply searched manually in the string for the tag I wanted, not ideal but did work.

Round float to x decimals?

Use the built-in function round():

In [23]: round(66.66666666666,4)
Out[23]: 66.6667

In [24]: round(1.29578293,6)
Out[24]: 1.295783

help on round():

round(number[, ndigits]) -> floating point number

Round a number to a given precision in decimal digits (default 0 digits). This always returns a floating point number. Precision may be negative.

Resolve promises one after another (i.e. in sequence)?

(function() {
  function sleep(ms) {
    return new Promise(function(resolve) {
      setTimeout(function() {
        return resolve();
      }, ms);
    });
  }

  function serial(arr, index, results) {
    if (index == arr.length) {
      return Promise.resolve(results);
    }
    return new Promise(function(resolve, reject) {
      if (!index) {
        index = 0;
        results = [];
      }
      return arr[index]()
        .then(function(d) {
          return resolve(d);
        })
        .catch(function(err) {
          return reject(err);
        });
    })
      .then(function(result) {
        console.log("here");
        results.push(result);
        return serial(arr, index + 1, results);
      })
      .catch(function(err) {
        throw err;
      });
  }

  const a = [5000, 5000, 5000];

  serial(a.map(x => () => sleep(x)));
})();

Here the key is how you call the sleep function. You need to pass an array of functions which itself returns a promise instead of an array of promises.

What is the basic difference between the Factory and Abstract Factory Design Patterns?

Both Factory Method and Abstract Factory keep the clients decoupled from the concrete types. Both create objects, but Factory method uses inheritance whereas Abstract Factory use composition.

The Factory Method is inherited in subclasses to create the concrete objects(products) whereas Abstract Factory provide interface for creating the family of related products and subclass of these interface define how to create related products.

Then these subclasses when instantiated is passed into product classes where it is used as abstract type. The related products in an Abstract Factory are often implemented using Factory Method.

How to refresh datagrid in WPF

Reload the datasource of your grid after the update

myGrid.ItemsSource = null;
myGrid.ItemsSource = myDataSource;

How to format date and time in Android?

This code work for me!

Date d = new Date();
    CharSequence s = android.text.format.DateFormat.format("MM-dd-yy hh-mm-ss",d.getTime());
    Toast.makeText(this,s.toString(),Toast.LENGTH_SHORT).show();

JavaScript: location.href to open in new window/tab?

You can also open a new tab calling to an action method with parameter like this:

   var reportDate = $("#inputDateId").val();
   var url = '@Url.Action("PrintIndex", "Callers", new {dateRequested = "findme"})';
   window.open(window.location.href = url.replace('findme', reportDate), '_blank');

Converting double to integer in Java

is there a possibility that casting a double created via Math.round() will still result in a truncated down number

No, round() will always round your double to the correct value, and then, it will be cast to an long which will truncate any decimal places. But after rounding, there will not be any fractional parts remaining.

Here are the docs from Math.round(double):

Returns the closest long to the argument. The result is rounded to an integer by adding 1/2, taking the floor of the result, and casting the result to type long. In other words, the result is equal to the value of the expression:

(long)Math.floor(a + 0.5d)

Get current URL with jQuery?

You'll want to use JavaScript's built-in window.location object.

Styling input radio with css

Here is simple example of how you can do this.

Just replace the image file and you are done.

HTML Code

<input type="radio" id="r1" name="rr" />
<label for="r1"><span></span>Radio Button 1</label>
<p>
<input type="radio" id="r2" name="rr" />
<label for="r2"><span></span>Radio Button 2</label>

CSS

input[type="radio"] {
    display:none;
}

input[type="radio"] + label {
    color:#f2f2f2;
    font-family:Arial, sans-serif;
    font-size:14px;
}

input[type="radio"] + label span {
    display:inline-block;
    width:19px;
    height:19px;
    margin:-1px 4px 0 0;
    vertical-align:middle;
    background:url(check_radio_sheet.png) -38px top no-repeat;
    cursor:pointer;
}

input[type="radio"]:checked + label span {
    background:url(check_radio_sheet.png) -57px top no-repeat;
}

Working DEMO

C# get and set properties for a List Collection

Your setters are strange, which is why you may be seeing a problem.

First, consider whether you even need these setters - if so, they should take a List<string>, not just a string:

set
{
    _subHead = value;
}

These lines:

newSec.subHead.Add("test string");

Are calling the getter and then call Add on the returned List<string> - the setter is not invoked.

java.util.zip.ZipException: duplicate entry during packageAllDebugClassesForMultiDex

My understanding is that there are duplicate references to the same API (Likely different version numbers). It should be reasonably easy to debug when building from the command line.

Try ./gradlew yourBuildVariantName --debug from the command line.

The offending item will be the first failure. An example might look like:

14:32:29.171 [INFO] [org.gradle.api.Task] INPUT: /Users/mydir/Documents/androidApp/BaseApp/build/intermediates/exploded-aar/theOffendingAAR/libs/google-play-services.jar

14:32:29.171 [DEBUG] [org.gradle.api.internal.tasks.execution.ExecuteAtMostOnceTaskExecuter] Finished executing task ':BaseApp:packageAllyourBuildVariantNameClassesForMultiDex'

14:32:29.172 [LIFECYCLE] [class org.gradle.TaskExecutionLogger] :BaseApp:packageAllyourBuildVariantNameClassesForMultiDex FAILED'

In the case above, the aar file that I'd included in my libs directory (theOffendingAAR) included the Google Play Services jar (yes the whole thing. yes I know.) file whilst my BaseApp build file utilised location services:

compile 'com.google.android.gms:play-services-location:6.5.87'

You can safely remove the offending item from your build file(s), clean and rebuild (repeat if necessary).

How to get current time with jQuery

Using JavaScript native Date functions you can get hours, minutes and seconds as you want. If you wish to format date and time in particular way you may want to implement a method extending JavaScript Date prototype.

Here is one already implemented: https://github.com/jacwright/date.format

how to rotate a bitmap 90 degrees

Below is the code to rotate or re size your image in android

public class bitmaptest extends Activity {
    @Override
    public void onCreate(Bundle icicle) {
        super.onCreate(icicle);
        LinearLayout linLayout = new LinearLayout(this);

        // load the origial BitMap (500 x 500 px)
        Bitmap bitmapOrg = BitmapFactory.decodeResource(getResources(),
               R.drawable.android);

        int width = bitmapOrg.width();
        int height = bitmapOrg.height();
        int newWidth = 200;
        int newHeight = 200;

        // calculate the scale - in this case = 0.4f
        float scaleWidth = ((float) newWidth) / width;
        float scaleHeight = ((float) newHeight) / height;

        // createa matrix for the manipulation
        Matrix matrix = new Matrix();
        // resize the bit map
        matrix.postScale(scaleWidth, scaleHeight);
        // rotate the Bitmap
        matrix.postRotate(45);

        // recreate the new Bitmap
        Bitmap resizedBitmap = Bitmap.createBitmap(bitmapOrg, 0, 0,
                          width, height, matrix, true);

        // make a Drawable from Bitmap to allow to set the BitMap
        // to the ImageView, ImageButton or what ever
        BitmapDrawable bmd = new BitmapDrawable(resizedBitmap);

        ImageView imageView = new ImageView(this);

        // set the Drawable on the ImageView
        imageView.setImageDrawable(bmd);

        // center the Image
        imageView.setScaleType(ScaleType.CENTER);

        // add ImageView to the Layout
        linLayout.addView(imageView,
                new LinearLayout.LayoutParams(
                      LayoutParams.FILL_PARENT, LayoutParams.FILL_PARENT
                )
        );

        // set LinearLayout as ContentView
        setContentView(linLayout);
    }
}

You can also check this link for details : http://www.anddev.org/resize_and_rotate_image_-_example-t621.html

Make the console wait for a user input to close

I used simple hack, asking windows to use cmd commands , and send it to null.

// Class for Different hacks for better CMD Display
import java.io.IOException;
public class CMDWindowEffets
{
    public static void getch() throws IOException, InterruptedException
    {
        new ProcessBuilder("cmd", "/c", "pause > null").inheritIO().start().waitFor();
    }    
}

ACCESS_FINE_LOCATION AndroidManifest Permissions Not Being Granted

just remove s from the permission you are using sss you have to use ss

To show error message without alert box in Java Script

First you are trying to write to the innerHTML of the input field. This will not work. You need to have a div or span to write to. Try something like:

First_Name
<input type=text id=fname name=fname onblur="validate()"> </input>
<div id="fname_error"></div>

Then change your validate function to read

if(myform.fname.value.length==0)
    {
    document.getElementById("fname_error").innerHTML="this is invalid name ";
    }

Second, I'm always hesitant about using onBlur for this kind of thing. It is possible to submit a form without exiting the field (e.g. return key) in which case your validation code will not be executed. I prefer to run the validation from the button that submits the form and then call the submit() from within the function only if the document has passed validation.

ApiNotActivatedMapError for simple html page using google-places-api

Have you tried following the advice on the linked help page? The help page at http://g.co/mapsJSApiErrors says:

ApiNotActivatedMapError

The Google Maps JavaScript API is not activated on your API project. You may need to enable the Google Maps JavaScript API under APIs in the Google Developers Console.

See Obtaining an API key.

So check that the key you are using has Google Maps JavaScript API enabled.

Java, Calculate the number of days between two dates

If you're sick of messing with java you can just send it to db2 as part of your query:

select date1, date2, days(date1) - days(date2) from table

will return date1, date2 and the difference in days between the two.

Amazon products API - Looking for basic overview and information

Your post contains several questions, so I'll try to answer them one at a time:

  1. The API you're interested in is the Product Advertising API (PA). It allows you programmatic access to search and retrieve product information from Amazon's catalog. If you're having trouble finding information on the API, that's because the web service has undergone two name changes in recent history: it was also known as ECS and AAWS.
  2. The signature process you're referring to is the same HMAC signature that all of the other AWS services use for authentication. All that's required to sign your requests to the Product Advertising API is a function to compute a SHA-1 hash and and AWS developer key. For more information, see the section of the developer documentation on signing requests.
  3. As far as I know, there is no support for retrieving RSS feeds of products or tags through PA. If anyone has information suggesting otherwise, please correct me.
  4. Either the REST or SOAP APIs should make your use case very straight forward. Amazon provides a fairly basic "getting started" guide available here. As well, you can view the complete API developer documentation here.

Although the documentation is a little hard to find (likely due to all the name changes), the PA API is very well documented and rather elegant. With a modicum of elbow grease and some previous experience in calling out to web services, you shouldn't have any trouble getting the information you need from the API.

The remote server returned an error: (407) Proxy Authentication Required

I had a similar proxy related problem. In my case it was enough to add:

webRequest.Proxy.Credentials = new NetworkCredential("user", "password", "domain");

Expected response code 250 but got code "530", with message "530 5.7.1 Authentication required

I believe this has been answered in some sections already, just test with gmail for your "MAIL_HOST" instead and don't forget to clear cache. Setup like below: Firstly, you need to setup 2 step verification here google security. An App Password link will appear and you can get your App Password to insert into below "MAIL_PASSWORD". More info on getting App Password here

MAIL_DRIVER=smtp
[email protected]
MAIL_FROM_NAME=DomainName
MAIL_HOST=smtp.gmail.com
MAIL_PORT=587
[email protected]
MAIL_PASSWORD=YOUR_GMAIL_CREATED_APP_PASSWORD
MAIL_ENCRYPTION=tls

Clear cache with:

php artisan config:cache

How to assert greater than using JUnit Assert?

You should add Hamcrest-library to your Build Path. It contains the needed Matchers.class which has the lessThan() method.

Dependency as below.

<dependency>
  <groupId>org.hamcrest</groupId>
  <artifactId>hamcrest-library</artifactId>
  <version>1.3</version>
  <scope>test</scope>
</dependency>