How to find specific lines in a table using Selenium?
if you want to access table cell
WebElement thirdCell = driver.findElement(By.Xpath("//table/tbody/tr[2]/td[1]"));
If you want to access nested table cell -
WebElement thirdCell = driver.findElement(By.Xpath("//table/tbody/tr[2]/td[2]"+//table/tbody/tr[1]/td[2]));
For more details visit this Tutorial
Android Studio update -Error:Could not run build action using Gradle distribution
I had same issue. I have tried many things but nothing worked Until I try following:
- Close Android Studio
- Delete any directory matching
gradle-[version]-all
within C:\Users\<username>\.gradle\wrapper\dists\
. If you encounter a "File in use" error (or similar), terminate any running Java executables.
- Open Android Studio as Administrator.
- Try to sync project files.
- If the above does not work, try restarting your computer and/or delete the project's
.gradle
directory.
- Open the problem project and trigger a Gradle sync.
How to get SLF4J "Hello World" working with log4j?
Following is an example. You can see the details http://jkssweetlife.com/configure-slf4j-working-various-logging-frameworks/ and download the full codes here.
Add following dependency to your pom if you are using maven, otherwise, just download the jar files and put on your classpath
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-api</artifactId>
<version>1.7.7</version>
</dependency>
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-log4j12</artifactId>
<version>1.7.7</version>
</dependency>
Configure log4j.properties
log4j.rootLogger=TRACE, stdout
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.Target=System.out
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%d{yyyy-MM-dd'T'HH:mm:ss.SSS} %-5p [%c] - %m%n
Java example
public class Slf4jExample {
public static void main(String[] args) {
Logger logger = LoggerFactory.getLogger(Slf4jExample.class);
final String message = "Hello logging!";
logger.trace(message);
logger.debug(message);
logger.info(message);
logger.warn(message);
logger.error(message);
}
}
Changing datagridview cell color based on condition
Kyle's and Simon's answers are gross waste of CPU resources. CellFormatting
and CellPainting
events occur far too many times and should not be used for applying styles. Here are two better ways of doing it:
If your DataGridView or at least the columns that decide cell style are read-only, you should change DefaultCellStyle of rows in RowsAdded
event. This event occurs only once when a new row is added. The condition should be evaluated at that time and DefaultCellStyle
of the row should be set therein. Note that this event occurs for DataBound situations too.
If your DataGridView or those columns allow editing, you should use CellEndEdit
or CommitEdit
events to change DefaultCellStyle
.
if (boolean condition) in Java
if (turnedOn) {
//do stuff when the condition is false or true?
}
else {
//do else of if
}
It can be written like:
if (turnedOn == true) {
//do stuff when the condition is false or true?
}
else { // turnedOn == false or !turnedOn
//do else of if
}
So if your turnedOn
variable is true, if will be called, if is assigned to false, else will be called. boolean values are implicitly assigned to false if you won't assign them explicitly e.q. turnedOn = true
getElementById in React
You need to have your function in the componentDidMount
lifecycle since this is the function that is called when the DOM has loaded.
Make use of refs
to access the DOM element
<input type="submit" className="nameInput" id="name" value="cp-dev1" onClick={this.writeData} ref = "cpDev1"/>
componentDidMount: function(){
var name = React.findDOMNode(this.refs.cpDev1).value;
this.someOtherFunction(name);
}
See this answer for more info on How to access the dom element in React
Sum of Numbers C++
First, you have two variables of the same name i
. This calls for confusion.
Second, you should declare a variable called sum
, which is initially zero. Then, in a loop, you should add to it the numbers from 1 upto and including positiveInteger
. After that, you should output the sum
.
Calculate a MD5 hash from a string
Was trying to create a string representation of MD5 hash using LINQ, however, none of the answers were LINQ solutions, therefore adding this to the smorgasbord of available solutions.
string result;
using (MD5 hash = MD5.Create())
{
result = String.Join
(
"",
from ba in hash.ComputeHash
(
Encoding.UTF8.GetBytes(observedText)
)
select ba.ToString("x2")
);
}
Generating random numbers with Swift
===== Swift 4.2 / Xcode 10 =====
let randomIntFrom0To10 = Int.random(in: 1..<10)
let randomFloat = Float.random(in: 0..<1)
// if you want to get a random element in an array
let greetings = ["hey", "hi", "hello", "hola"]
greetings.randomElement()
Under the hood Swift uses arc4random_buf
to get job done.
===== Swift 4.1 / Xcode 9 =====
arc4random()
returns a random number in the range of 0 to 4 294 967 295
drand48()
returns a random number in the range of 0.0 to 1.0
arc4random_uniform(N)
returns a random number in the range of 0 to N - 1
Examples:
arc4random() // => UInt32 = 2739058784
arc4random() // => UInt32 = 2672503239
arc4random() // => UInt32 = 3990537167
arc4random() // => UInt32 = 2516511476
arc4random() // => UInt32 = 3959558840
drand48() // => Double = 0.88642843322303122
drand48() // => Double = 0.015582849408328769
drand48() // => Double = 0.58409022031727176
drand48() // => Double = 0.15936862653180484
drand48() // => Double = 0.38371587480719427
arc4random_uniform(3) // => UInt32 = 0
arc4random_uniform(3) // => UInt32 = 1
arc4random_uniform(3) // => UInt32 = 0
arc4random_uniform(3) // => UInt32 = 1
arc4random_uniform(3) // => UInt32 = 2
arc4random_uniform() is recommended over constructions like arc4random() % upper_bound
as it avoids "modulo bias" when the upper bound is not a power of two.
how can I debug a jar at runtime?
Even though it is a runnable jar, you can still run it from a console -- open a terminal window, navigate to the directory containing the jar, and enter "java -jar yourJar.jar". It will run in that terminal window, and sysout and syserr output will appear there, including stack traces from uncaught exceptions. Be sure to have your debug set to true when you compile. And good luck.
Just thought of something else -- if you're on Win7, it often has permission problems with user applications writing files to specific directories. Make sure the directory to which you are writing your output file is one for which you have permissions.
In a future project, if it's big enough, you can use one of the standard logging facilities for 'debug' output; then it will be easy(ier) to redirect it to a file instead of depending on having a console. But for a smaller job like this, this should be fine.
Django Template Variables and Javascript
I was facing simillar issue and answer suggested by S.Lott worked for me.
<script type="text/javascript">
var a = "{{someDjangoVariable}}"
</script>
However I would like to point out major implementation limitation here.
If you are planning to put your javascript code in different file and include that file in your template. This won't work.
This works only when you main template and javascript code is in same file.
Probably django team can address this limitation.
Access-Control-Allow-Origin and Angular.js $http
I've had success with express and editing the res.header
. Mine matches yours pretty closely but I have a different Allow-Headers
as noted below:
res.header("Access-Control-Allow-Headers", "Origin, X-Requested-With, Content-Type, Accept");
I'm also using Angular and Node/Express, but I don't have the headers called out in the Angular code only the node/express
git visual diff between branches
If you're using github you can use the website for this:
github.com/url/to/your/repo/compare/SHA_of_tip_of_one_branch...SHA_of_tip_of_another_branch
That will show you a compare of the two.
HTML5 Canvas Rotate Image
As @markE mention in his answer
the alternative is to untranslate & unrotate after drawing
It is much faster than context save and restore.
Here is an example
// translate and rotate
this.context.translate(x,y);
this.context.rotate(radians);
this.context.translate(-x,-y);
this.context.drawImage(...);
// untranslate and unrotate
this.context.translate(x, y);
this.context.rotate(-radians);
this.context.translate(-x,-y);
How can I scan barcodes on iOS?
If support for the iPad 2 or iPod Touch is important for your application, I'd choose a barcode scanner SDK that can decode barcodes in blurry images, such as our Scandit barcode scanner SDK for iOS and Android. Decoding blurry barcode images is also helpful on phones with autofocus cameras because the user does not have to wait for the autofocus to kick in.
Scandit comes with a free community price plan and also has a product API that makes it easy to convert barcode numbers into product names.
(Disclaimer: I'm a co-founder of Scandit)
How to add a .dll reference to a project in Visual Studio
Copy the downloaded DLL file in a custom folder on your dev drive, then add the reference to your project using the Browse button in the Add Reference
dialog.
Be sure that the new reference has the Copy Local = True
.
The Add Reference
dialog could be opened right-clicking on the References item in your project in Solution Explorer
UPDATE AFTER SOME YEARS
At the present time the best way to resolve all those problems is through the
Manage NuGet packages menu command of Visual Studio 2017/2019.
You can right click on the References node of your project and select that command. From the Browse tab search for the library you want to use in the NuGet repository, click on the item if found and then Install it. (Of course you need to have a package for that DLL and this is not guaranteed to exist)
Read about NuGet here
Bulk Insert into Oracle database: Which is better: FOR Cursor loop or a simple Select?
A simple insert/select like your 2nd option is far preferable. For each insert in the 1st option you require a context switch from pl/sql to sql. Run each with trace/tkprof and examine the results.
If, as Michael mentions, your rollback cannot handle the statement then have your dba give you more. Disk is cheap, while partial results that come from inserting your data in multiple passes is potentially quite expensive. (There is almost no undo associated with an insert.)
C# event with custom arguments
public enum MyEvents
{
Event1
}
public class CustomEventArgs : EventArgs
{
public MyEvents MyEvents { get; set; }
}
private EventHandler<CustomEventArgs> onTrigger;
public event EventHandler<CustomEventArgs> Trigger
{
add
{
onTrigger += value;
}
remove
{
onTrigger -= value;
}
}
protected void OnTrigger(CustomEventArgs e)
{
if (onTrigger != null)
{
onTrigger(this, e);
}
}
How to join entries in a set into one string?
Sets don't have a join
method but you can use str.join
instead.
', '.join(set_3)
The str.join
method will work on any iterable object including lists and sets.
Note: be careful about using this on sets containing integers; you will need to convert the integers to strings before the call to join. For example
set_4 = {1, 2}
', '.join(str(s) for s in set_4)
AttributeError: 'module' object has no attribute 'urlretrieve'
Suppose you have following lines of code
MyUrl = "www.google.com" #Your url goes here
urllib.urlretrieve(MyUrl)
If you are receiving following error message
AttributeError: module 'urllib' has no attribute 'urlretrieve'
Then you should try following code to fix the issue:
import urllib.request
MyUrl = "www.google.com" #Your url goes here
urllib.request.urlretrieve(MyUrl)
Overlay with spinner
As an update, for Angular 7, a very good example, loading plus http interceptor, here: https://nezhar.com/blog/create-a-loading-screen-for-angular-apps/.
For version 6, you need a small adjustment when you use Subject. You need to add the generic type.
loadingStatus: Subject<boolean> = new Subject();
I'm using angular material, so instead of a loading text, you can use mat-spinner.
<mat-spinner></mat-spinner>
Update: the code from the previous page will not complete work (regarding the interceptor part), but here you have the complete solution: https://github.com/nezhar/snypy-frontend
And as Miranda recommended into comments, here is also the solution:
The loading screen component:
loading-screen.component.ts
import { Component, ElementRef, ChangeDetectorRef, OnDestroy, AfterViewInit } from '@angular/core';
import { Subscription } from 'rxjs';
import { LoadingScreenService } from '../services/loading-screen.service';
@Component({
selector: 'app-loading-screen',
templateUrl: './loading-screen.component.html',
styleUrls: ['./loading-screen.component.css']
})
export class LoadingScreenComponent implements AfterViewInit, OnDestroy {
loading: boolean = false;
loadingSubscription: Subscription;
constructor(
private loadingScreenService: LoadingScreenService,
private _elmRef: ElementRef,
private _changeDetectorRef: ChangeDetectorRef
) { }
ngAfterViewInit(): void {
this._elmRef.nativeElement.style.display = 'none';
this.loadingSubscription = this.loadingScreenService.loadingStatus.pipe().subscribe(
(status: boolean) => {
this._elmRef.nativeElement.style.display = status ? 'block' : 'none';
this._changeDetectorRef.detectChanges();
}
);
}
ngOnDestroy() {
console.log("inside destroy loading component");
this.loadingSubscription.unsubscribe();
}
}
loading-screen.component.html
<div id="overlay">
<mat-spinner class="content"></mat-spinner>
</div>
loading-screen.component.css
#overlay {
position: fixed; /* Sit on top of the page content */
display: block; /* Hidden by default */
width: 100%; /* Full width (cover the whole page) */
height: 100%; /* Full height (cover the whole page) */
top: 0;
left: 0;
right: 0;
bottom: 0;
background-color: rgba(60, 138, 255, 0.1); /* Black background with opacity */
opacity: 0.5;
z-index: 2; /* Specify a stack order in case you're using a different order for other elements */
cursor: progress; /* Add a pointer on hover */
}
.content {
position: absolute;
top: 50%;
left: 50%;
font-size: 50px;
color: white;
transform: translate(-50%, -50%);
-ms-transform: translate(-50%, -50%);
}
Don't forget to add the component to your root component. In my case, AppComponent
app.component.html
<app-loading-screen></app-loading-screen>
The service that will manage the component: loading-screen.service.ts
import { Injectable } from '@angular/core';
import { Subject } from 'rxjs';
@Injectable({
providedIn: 'root'
})
export class LoadingScreenService {
constructor() { }
private _loading: boolean = false;
loadingStatus: Subject<boolean> = new Subject();
get loading(): boolean {
console.log("get loading: " + this._loading);
return this._loading;
}
set loading(value) {
console.log("get loading: " + value);
this._loading = value;
this.loadingStatus.next(value);
}
startLoading() {
console.log("startLoading");
this.loading = true;
}
stopLoading() {
console.log("stopLoading");
this.loading = false;
}
}
Here is the http interceptor, which will show/hide the component, using the previous service.
loading-screen-interceptor.ts
import { Injectable } from '@angular/core';
import { HttpInterceptor, HttpRequest, HttpHandler, HttpEvent } from '@angular/common/http';
import { LoadingScreenService } from '../services/loading-screen.service';
import { Observable } from 'rxjs';
import { finalize } from 'rxjs/operators';
@Injectable()
export class LoadingScreenInterceptor implements HttpInterceptor {
activeRequests: number = 0;
constructor(
private loadingScreenService: LoadingScreenService
) { }
intercept(request: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>> {
console.log("inside interceptor");
if (this.activeRequests === 0) {
this.loadingScreenService.startLoading();
}
this.activeRequests++;
return next.handle(request).pipe(
finalize(() => {
this.activeRequests--;
if (this.activeRequests === 0) {
this.loadingScreenService.stopLoading();
}
})
)
};
}
And in your app.module.ts, don't forget to config the interceptor
providers: [
{
provide: HTTP_INTERCEPTORS,
useClass: LoadingScreenInterceptor,
multi: true
}
]
Renaming part of a filename
I like to do this with sed. In you case:
for x in DET01-*.dat; do
echo $x | sed -r 's/DET01-ABC-(.+)\.dat/mv -v "\0" "DET01-XYZ-\1.dat"/'
done | sh -e
It is best to omit the "sh -e" part first to see what will be executed.
'uint32_t' does not name a type
just navigate to /usr/include/x86_64-linux-gnu/bits
open stdint-uintn.h and add these lines
typedef __uint8_t uint8_t;
typedef __uint16_t uint16_t;
typedef __uint32_t uint32_t;
typedef __uint64_t uint64_t;
again open stdint-intn.h and add
typedef __int8_t int8_t;
typedef __int16_t int16_t;
typedef __int32_t int32_t;
typedef __int64_t int64_t;
note these lines are already present just copy and add the missing lines cheerss..
How can I hash a password in Java?
You can actually use a facility built in to the Java runtime to do this. The SunJCE in Java 6 supports PBKDF2, which is a good algorithm to use for password hashing.
byte[] salt = new byte[16];
random.nextBytes(salt);
KeySpec spec = new PBEKeySpec("password".toCharArray(), salt, 65536, 128);
SecretKeyFactory f = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA1");
byte[] hash = f.generateSecret(spec).getEncoded();
Base64.Encoder enc = Base64.getEncoder();
System.out.printf("salt: %s%n", enc.encodeToString(salt));
System.out.printf("hash: %s%n", enc.encodeToString(hash));
Here's a utility class that you can use for PBKDF2 password authentication:
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
import java.security.spec.InvalidKeySpecException;
import java.security.spec.KeySpec;
import java.util.Arrays;
import java.util.Base64;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.PBEKeySpec;
/**
* Hash passwords for storage, and test passwords against password tokens.
*
* Instances of this class can be used concurrently by multiple threads.
*
* @author erickson
* @see <a href="http://stackoverflow.com/a/2861125/3474">StackOverflow</a>
*/
public final class PasswordAuthentication
{
/**
* Each token produced by this class uses this identifier as a prefix.
*/
public static final String ID = "$31$";
/**
* The minimum recommended cost, used by default
*/
public static final int DEFAULT_COST = 16;
private static final String ALGORITHM = "PBKDF2WithHmacSHA1";
private static final int SIZE = 128;
private static final Pattern layout = Pattern.compile("\\$31\\$(\\d\\d?)\\$(.{43})");
private final SecureRandom random;
private final int cost;
public PasswordAuthentication()
{
this(DEFAULT_COST);
}
/**
* Create a password manager with a specified cost
*
* @param cost the exponential computational cost of hashing a password, 0 to 30
*/
public PasswordAuthentication(int cost)
{
iterations(cost); /* Validate cost */
this.cost = cost;
this.random = new SecureRandom();
}
private static int iterations(int cost)
{
if ((cost < 0) || (cost > 30))
throw new IllegalArgumentException("cost: " + cost);
return 1 << cost;
}
/**
* Hash a password for storage.
*
* @return a secure authentication token to be stored for later authentication
*/
public String hash(char[] password)
{
byte[] salt = new byte[SIZE / 8];
random.nextBytes(salt);
byte[] dk = pbkdf2(password, salt, 1 << cost);
byte[] hash = new byte[salt.length + dk.length];
System.arraycopy(salt, 0, hash, 0, salt.length);
System.arraycopy(dk, 0, hash, salt.length, dk.length);
Base64.Encoder enc = Base64.getUrlEncoder().withoutPadding();
return ID + cost + '$' + enc.encodeToString(hash);
}
/**
* Authenticate with a password and a stored password token.
*
* @return true if the password and token match
*/
public boolean authenticate(char[] password, String token)
{
Matcher m = layout.matcher(token);
if (!m.matches())
throw new IllegalArgumentException("Invalid token format");
int iterations = iterations(Integer.parseInt(m.group(1)));
byte[] hash = Base64.getUrlDecoder().decode(m.group(2));
byte[] salt = Arrays.copyOfRange(hash, 0, SIZE / 8);
byte[] check = pbkdf2(password, salt, iterations);
int zero = 0;
for (int idx = 0; idx < check.length; ++idx)
zero |= hash[salt.length + idx] ^ check[idx];
return zero == 0;
}
private static byte[] pbkdf2(char[] password, byte[] salt, int iterations)
{
KeySpec spec = new PBEKeySpec(password, salt, iterations, SIZE);
try {
SecretKeyFactory f = SecretKeyFactory.getInstance(ALGORITHM);
return f.generateSecret(spec).getEncoded();
}
catch (NoSuchAlgorithmException ex) {
throw new IllegalStateException("Missing algorithm: " + ALGORITHM, ex);
}
catch (InvalidKeySpecException ex) {
throw new IllegalStateException("Invalid SecretKeyFactory", ex);
}
}
/**
* Hash a password in an immutable {@code String}.
*
* <p>Passwords should be stored in a {@code char[]} so that it can be filled
* with zeros after use instead of lingering on the heap and elsewhere.
*
* @deprecated Use {@link #hash(char[])} instead
*/
@Deprecated
public String hash(String password)
{
return hash(password.toCharArray());
}
/**
* Authenticate with a password in an immutable {@code String} and a stored
* password token.
*
* @deprecated Use {@link #authenticate(char[],String)} instead.
* @see #hash(String)
*/
@Deprecated
public boolean authenticate(String password, String token)
{
return authenticate(password.toCharArray(), token);
}
}
Ansible: How to delete files and folders inside a directory?
Isn't it that simple ... tested working ..
eg.
---
- hosts: localhost
vars:
cleandir: /var/lib/cloud/
tasks:
- shell: ls -a -I '.' -I '..' {{ cleandir }}
register: ls2del
ignore_errors: yes
- name: Cleanup {{ cleandir }}
file:
path: "{{ cleandir }}{{ item }}"
state: absent
with_items: "{{ ls2del.stdout_lines }}"
Restoring MySQL database from physical files
I once copied these files to the database storage folder for a mysql database which was working, started the db and waited for it to "repair" the files, then extracted them with mysqldump.
Redirect all output to file in Bash
You can use exec
command to redirect all stdout/stderr output of any commands later.
sample script:
exec 2> your_file2 > your_file1
your other commands.....
Hide/Show Action Bar Option Menu Item for different fragments
To show action items (action buttons) in the ActionBar of fragments where they are only needed, do this:
Lets say you want the save
button to only show in the fragment where you accept input for items and not in the Fragment where you view a list of items, add this to the OnCreateOptionsMenu
method of the Fragment where you view the items:
public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
if (menu != null) {
menu.findItem(R.id.action_save_item).setVisible(false);
}
}
NOTE: For this to work, you need the onCreate()
method in your Fragment (where you want to hide item button, the item view fragment in our example) and add setHasOptionsMenu(true)
like this:
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setHasOptionsMenu(true);
}
Might not be the best option, but it works and it's simple.
How to set underline text on textview?
you're almost there: just don't call toString()
on Html.fromHtml()
and you get a Spanned Object which will do the job ;)
tvHide.setText(Html.fromHtml("<p><u>Hide post</u></p>"));
Variables as commands in bash scripts
Quoting spaces inside variables such that the shell will re-interpret things properly is hard. It's this type of thing that prompts me to reach for a stronger language. Whether that's perl or python or ruby or whatever (I choose perl, but that's not always for everyone), it's just something that will allow you to bypass the shell for quoting.
It's not that I've never managed to get it right with liberal doses of eval, but just that eval gives me the eebie-jeebies (becomes a whole new headache when you want to take user input and eval it, though in this case you'd be taking stuff that you wrote and evaling that instead), and that I've gotten headaches in debugging.
With perl, as my example, I'd be able to do something like:
@tar_cmd = ( qw(tar cv), $directory );
@encrypt_cmd = ( qw(openssl des3 -salt) );
@split_cmd = ( qw(split -b 1024m -), $backup_file );
The hard part here is doing the pipes - but a bit of IO::Pipe, fork, and reopening stdout and stderr, and it's not bad. Some would say that's worse than quoting the shell properly, and I understand where they're coming from, but, for me, this is easier to read, maintain, and write. Heck, someone could take the hard work out of this and create a IO::Pipeline module and make the whole thing trivial ;-)
How to reverse a singly linked list using only two pointers?
As an alternative, you can use recursion-
struct node* reverseList(struct node *head)
{
if(head == NULL) return NULL;
if(head->next == NULL) return head;
struct node* second = head->next;
head->next = NULL;
struct node* remaining = reverseList(second);
second->next = head;
return remaining;
}
Object comparison in JavaScript
I wrote this piece of code for object comparison, and it seems to work. check the assertions:
function countProps(obj) {
var count = 0;
for (k in obj) {
if (obj.hasOwnProperty(k)) {
count++;
}
}
return count;
};
function objectEquals(v1, v2) {
if (typeof(v1) !== typeof(v2)) {
return false;
}
if (typeof(v1) === "function") {
return v1.toString() === v2.toString();
}
if (v1 instanceof Object && v2 instanceof Object) {
if (countProps(v1) !== countProps(v2)) {
return false;
}
var r = true;
for (k in v1) {
r = objectEquals(v1[k], v2[k]);
if (!r) {
return false;
}
}
return true;
} else {
return v1 === v2;
}
}
assert.isTrue(objectEquals(null,null));
assert.isFalse(objectEquals(null,undefined));
assert.isTrue(objectEquals("hi","hi"));
assert.isTrue(objectEquals(5,5));
assert.isFalse(objectEquals(5,10));
assert.isTrue(objectEquals([],[]));
assert.isTrue(objectEquals([1,2],[1,2]));
assert.isFalse(objectEquals([1,2],[2,1]));
assert.isFalse(objectEquals([1,2],[1,2,3]));
assert.isTrue(objectEquals({},{}));
assert.isTrue(objectEquals({a:1,b:2},{a:1,b:2}));
assert.isTrue(objectEquals({a:1,b:2},{b:2,a:1}));
assert.isFalse(objectEquals({a:1,b:2},{a:1,b:3}));
assert.isTrue(objectEquals({1:{name:"mhc",age:28}, 2:{name:"arb",age:26}},{1:{name:"mhc",age:28}, 2:{name:"arb",age:26}}));
assert.isFalse(objectEquals({1:{name:"mhc",age:28}, 2:{name:"arb",age:26}},{1:{name:"mhc",age:28}, 2:{name:"arb",age:27}}));
assert.isTrue(objectEquals(function(x){return x;},function(x){return x;}));
assert.isFalse(objectEquals(function(x){return x;},function(y){return y+2;}));
Enum Naming Convention - Plural
Coming in a bit late...
There's an important difference between your question and the one you mention (which I asked ;-):
You put the enum definition out of the class, which allows you to have the same name for the enum and the property:
public enum EntityType {
Type1, Type2
}
public class SomeClass {
public EntityType EntityType {get; set;} // This is legal
}
In this case, I'd follow the MS guidelins and use a singular name for the enum (plural for flags). It's probaby the easiest solution.
My problem (in the other question) is when the enum is defined in the scope of the class, preventing the use of a property named exactly after the enum.
How can we print line numbers to the log in java
private static final int CLIENT_CODE_STACK_INDEX;
static {
// Finds out the index of "this code" in the returned stack Trace - funny but it differs in JDK 1.5 and 1.6
int i = 0;
for (StackTraceElement ste : Thread.currentThread().getStackTrace()) {
i++;
if (ste.getClassName().equals(Trace.class.getName())) {
break;
}
}
CLIENT_CODE_STACK_INDEX = i;
}
private String methodName() {
StackTraceElement ste=Thread.currentThread().getStackTrace()[CLIENT_CODE_STACK_INDEX+1];
return ste.getMethodName()+":"+ste.getLineNumber();
}
Are PostgreSQL column names case-sensitive?
if use JPA I recommend change to lowercase schema, table and column names, you can use next intructions for help you:
select
psat.schemaname,
psat.relname,
pa.attname,
psat.relid
from
pg_catalog.pg_stat_all_tables psat,
pg_catalog.pg_attribute pa
where
psat.relid = pa.attrelid
change schema name:
ALTER SCHEMA "XXXXX" RENAME TO xxxxx;
change table names:
ALTER TABLE xxxxx."AAAAA" RENAME TO aaaaa;
change column names:
ALTER TABLE xxxxx.aaaaa RENAME COLUMN "CCCCC" TO ccccc;
Change background position with jQuery
You guys are complicating things. You can simple do this from CSS.
#carousel li { background-position:0px 0px; }
#carousel li:hover { background-position:100px 0px; }
CASE .. WHEN expression in Oracle SQL
It will be easier to do using decode.
SELECT
status,
decode ( status, 'a1','Active',
'a2','Active',
'a3','Active',
'i','Inactive',
't','Terminated',
'Default')STATUSTEXT
FROM STATUS
Where do I find the definition of size_t?
size_t should be defined in your standard library's headers. In my experience, it usually is simply a typedef to unsigned int. The point, though, is that it doesn't have to be.
Types like size_t allow the standard library vendor the freedom to change its underlying data types if appropriate for the platform. If you assume size_t is always unsigned int (via casting, etc), you could run into problems in the future if your vendor changes size_t to be e.g. a 64-bit type. It is dangerous to assume anything about this or any other library type for this reason.
sklearn plot confusion matrix with labels
UPDATE:
In scikit-learn 0.22, there's a new feature to plot the confusion matrix directly.
See the documentation: sklearn.metrics.plot_confusion_matrix
OLD ANSWER:
I think it's worth mentioning the use of seaborn.heatmap
here.
import seaborn as sns
import matplotlib.pyplot as plt
ax= plt.subplot()
sns.heatmap(cm, annot=True, ax = ax); #annot=True to annotate cells
# labels, title and ticks
ax.set_xlabel('Predicted labels');ax.set_ylabel('True labels');
ax.set_title('Confusion Matrix');
ax.xaxis.set_ticklabels(['business', 'health']); ax.yaxis.set_ticklabels(['health', 'business']);
iOS change navigation bar title font and color
Here is an answer for your question:
Move your code to below method because navigation bar title updated after view loaded. I tried adding above code in viewDidLoad doesn't work, it works fine in viewDidAppear method.
-(void)viewDidAppear:(BOOL)animated{}
how to empty recyclebin through command prompt?
You can effectively "empty" the Recycle Bin from the command line by permanently deleting the Recycle Bin directory on the drive that contains the system files. (In most cases, this will be the C:
drive, but you shouldn't hardcode that value because it won't always be true. Instead, use the %systemdrive%
environment variable.)
The reason that this tactic works is because each drive has a hidden, protected folder with the name $Recycle.bin
, which is where the Recycle Bin actually stores the deleted files and folders. When this directory is deleted, Windows automatically creates a new directory.
So, to remove the directory, use the rd
command (r?emove d?irectory) with the /s
parameter, which indicates that all of the files and directories within the specified directory should be removed as well:
rd /s %systemdrive%\$Recycle.bin
Do note that this action will permanently delete all files and folders currently in the Recycle Bin from all user accounts. Additionally, you will (obviously) have to run the command from an elevated command prompt in order to have sufficient privileges to perform this action.
How can I get an int from stdio in C?
I'm not fully sure that this is what you're looking for, but if your question is how to read an integer using <stdio.h>
, then the proper syntax is
int myInt;
scanf("%d", &myInt);
You'll need to do a lot of error-handling to ensure that this works correctly, of course, but this should be a good start. In particular, you'll need to handle the cases where
- The
stdin
file is closed or broken, so you get nothing at all.
- The user enters something invalid.
To check for this, you can capture the return code from scanf
like this:
int result = scanf("%d", &myInt);
If stdin
encounters an error while reading, result
will be EOF
, and you can check for errors like this:
int myInt;
int result = scanf("%d", &myInt);
if (result == EOF) {
/* ... you're not going to get any input ... */
}
If, on the other hand, the user enters something invalid, like a garbage text string, then you need to read characters out of stdin
until you consume all the offending input. You can do this as follows, using the fact that scanf
returns 0 if nothing was read:
int myInt;
int result = scanf("%d", &myInt);
if (result == EOF) {
/* ... you're not going to get any input ... */
}
if (result == 0) {
while (fgetc(stdin) != '\n') // Read until a newline is found
;
}
Hope this helps!
EDIT: In response to the more detailed question, here's a more appropriate answer. :-)
The problem with this code is that when you write
printf("got the number: %d", scanf("%d", &x));
This is printing the return code from scanf
, which is EOF
on a stream error, 0
if nothing was read, and 1
otherwise. This means that, in particular, if you enter an integer, this will always print 1
because you're printing the status code from scanf
, not the number you read.
To fix this, change this to
int x;
scanf("%d", &x);
/* ... error checking as above ... */
printf("got the number: %d", x);
Hope this helps!
Inserting data into a MySQL table using VB.NET
Dim connString as String ="server=localhost;userid=root;password=123456;database=uni_park_db"
Dim conn as MySqlConnection(connString)
Dim cmd as MysqlCommand
Dim dt as New DataTable
Dim ireturn as Boolean
Private Sub Insert_Car()
Dim sql as String = "insert into members_car (car_id, member_id, model, color, chassis_id, plate_number, code) values (@car_id,@member_id,@model,@color,@chassis_id,@plate_number,@code)"
Dim cmd = new MySqlCommand(sql, conn)
cmd.Paramaters.AddwithValue("@car_id", txtCar.Text)
cmd.Paramaters.AddwithValue("@member_id", txtMember.Text)
cmd.Paramaters.AddwithValue("@model", txtModel.Text)
cmd.Paramaters.AddwithValue("@color", txtColor.Text)
cmd.Paramaters.AddwithValue("@chassis_id", txtChassis.Text)
cmd.Paramaters.AddwithValue("@plate_number", txtPlateNo.Text)
cmd.Paramaters.AddwithValue("@code", txtCode.Text)
Try
conn.Open()
If cmd.ExecuteNonQuery() > 0 Then
ireturn = True
End If
conn.Close()
Catch ex as Exception
ireturn = False
conn.Close()
End Try
Return ireturn
End Sub
java.util.Date to XMLGregorianCalendar
GregorianCalendar c = new GregorianCalendar();
c.setTime(yourDate);
XMLGregorianCalendar date2 = DatatypeFactory.newInstance().newXMLGregorianCalendar(c);
How to make MySQL handle UTF-8 properly
Your answer is you can configure by MySql Settings. In My Answer may be something gone out of context but this is also know is help for you.
how to configure Character Set
and Collation
.
For applications that store data using the default MySQL character set
and collation (latin1, latin1_swedish_ci
), no special configuration
should be needed. If applications require data storage using a
different character set or collation, you can configure character set
information several ways:
- Specify character settings per database. For example, applications
that use one database might require
utf8
, whereas applications that
use another database might require sjis.
- Specify character settings at server startup. This causes the server
to use the given settings for all applications that do not make other
arrangements.
- Specify character settings at configuration time, if you build MySQL
from source. This causes the server to use the given settings for all
applications, without having to specify them at server startup.
The examples shown here for your question to set utf8 character set , here also set collation for more helpful(utf8_general_ci
collation`).
Specify character settings per database
CREATE DATABASE new_db
DEFAULT CHARACTER SET utf8
DEFAULT COLLATE utf8_general_ci;
Specify character settings at server startup
[mysqld]
character-set-server=utf8
collation-server=utf8_general_ci
Specify character settings at MySQL configuration time
shell> cmake . -DDEFAULT_CHARSET=utf8 \
-DDEFAULT_COLLATION=utf8_general_ci
To see the values of the character set and collation system variables that apply to your connection, use these statements:
SHOW VARIABLES LIKE 'character_set%';
SHOW VARIABLES LIKE 'collation%';
This May be lengthy answer but there is all way, you can use. Hopeful my answer is helpful for you. for more information http://dev.mysql.com/doc/refman/5.7/en/charset-applications.html
What is the difference between "#!/usr/bin/env bash" and "#!/usr/bin/bash"?
Running a command through /usr/bin/env
has the benefit of looking for whatever the default version of the program is in your current environment.
This way, you don't have to look for it in a specific place on the system, as those paths may be in different locations on different systems. As long as it's in your path, it will find it.
One downside is that you will be unable to pass more than one argument (e.g. you will be unable to write /usr/bin/env awk -f
) if you wish to support Linux, as POSIX is vague on how the line is to be interpreted, and Linux interprets everything after the first space to denote a single argument. You can use /usr/bin/env -S
on some versions of env
to get around this, but then the script will become even less portable and break on fairly recent systems (e.g. even Ubuntu 16.04 if not later).
Another downside is that since you aren't calling an explicit executable, it's got the potential for mistakes, and on multiuser systems security problems (if someone managed to get their executable called bash
in your path, for example).
#!/usr/bin/env bash #lends you some flexibility on different systems
#!/usr/bin/bash #gives you explicit control on a given system of what executable is called
In some situations, the first may be preferred (like running python scripts with multiple versions of python, without having to rework the executable line). But in situations where security is the focus, the latter would be preferred, as it limits code injection possibilities.
How to read a string one letter at a time in python
A couple of things for ya:
The loading would be "better" like this:
with file('morsecodes.txt', 'rt') as f:
for line in f:
line = line.strip()
if len(line) > 0:
# do your stuff to parse the file
That way you don't need to close, and you don't need to manually load each line, etc., etc.
for letter in userInput:
if ValidateLetter(letter): # you need to define this
code = GetMorseCode(letter) # from my other answer
# do whatever you want
Slack URL to open a channel from browser
Referencing a channel within a conversation
To create a clickable reference to a channel in a Slack conversation, just type #
followed by the channel name. For example: #general
.
To grab a link to a channel through the Slack UI
To share the channel URL externally, you can grab its link by control-clicking (Mac) or right-clicking (Windows) on the channel name:
The link would look like this:
https://yourteam.slack.com/messages/C69S1L3SS
Note that this link doesn't change even if you change the name of the channel. So, it is better to use this link rather than the one based on channel's name.
To compose a URL for a channel based on channel name
https://yourteam.slack.com/channels/<channel_name>
Opening the above URL from a browser would launch the Slack client (if available) or open the slack channel on the browser itself.
To compose a URL for a direct message (DM) channel to a user
https://yourteam.slack.com/channels/<username>
Fragment MyFragment not attached to Activity
The problem with your code is the way the you are using the AsyncTask, because when you rotate the screen during your sleep thread:
Thread.sleep(2000)
the AsyncTask is still working, it is because you didn't cancel the AsyncTask instance properly in onDestroy() before the fragment rebuilds (when you rotate) and when this same AsyncTask instance (after rotate) runs onPostExecute(), this tries to find the resources with getResources() with the old fragment instance(an invalid instance):
getResources().getString(R.string.app_name)
which is equivalent to:
MyFragment.this.getResources().getString(R.string.app_name)
So the final solution is manage the AsyncTask instance (to cancel if this is still working) before the fragment rebuilds when you rotate the screen, and if canceled during the transition, restart the AsyncTask after reconstruction by the aid of a boolean flag:
public class MyFragment extends SherlockFragment {
private MyAsyncTask myAsyncTask = null;
private boolean myAsyncTaskIsRunning = true;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
if(savedInstanceState!=null) {
myAsyncTaskIsRunning = savedInstanceState.getBoolean("myAsyncTaskIsRunning");
}
if(myAsyncTaskIsRunning) {
myAsyncTask = new MyAsyncTask();
myAsyncTask.execute();
}
}
@Override
public void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
outState.putBoolean("myAsyncTaskIsRunning",myAsyncTaskIsRunning);
}
@Override
public void onDestroy() {
super.onDestroy();
if(myAsyncTask!=null) myAsyncTask.cancel(true);
myAsyncTask = null;
}
public class MyAsyncTask extends AsyncTask<Void, Void, Void>() {
public MyAsyncTask(){}
@Override
protected void onPreExecute() {
super.onPreExecute();
myAsyncTaskIsRunning = true;
}
@Override
protected Void doInBackground(Void... params) {
try {
Thread.sleep(2000);
} catch (InterruptedException ex) {}
return null;
}
@Override
protected void onPostExecute(Void result){
getResources().getString(R.string.app_name);
myAsyncTaskIsRunning = false;
myAsyncTask = null;
}
}
}
Check if number is prime number
/***
* Check a number is prime or not
* @param n the number
* @return {@code true} if {@code n} is prime
*/
public static boolean isPrime(int n) {
if (n == 2) {
return true;
}
if (n < 2 || n % 2 == 0) {
return false;
}
for (int i = 3; i <= Math.sqrt(n); i += 2) {
if (n % i == 0) {
return false;
}
}
return true;
}
c# dictionary How to add multiple values for single key?
Update: check for existence using TryGetValue
to do only one lookup in the case where you have the list:
List<int> list;
if (!dictionary.TryGetValue("foo", out list))
{
list = new List<int>();
dictionary.Add("foo", list);
}
list.Add(2);
Original:
Check for existence and add once, then key into the dictionary to get the list and add to the list as normal:
var dictionary = new Dictionary<string, List<int>>();
if (!dictionary.ContainsKey("foo"))
dictionary.Add("foo", new List<int>());
dictionary["foo"].Add(42);
dictionary["foo"].AddRange(oneHundredInts);
Or List<string>
as in your case.
As an aside, if you know how many items you are going to add to a dynamic collection such as List<T>
, favour the constructor that takes the initial list capacity: new List<int>(100);
.
This will grab the memory required to satisfy the specified capacity upfront, instead of grabbing small chunks every time it starts to fill up. You can do the same with dictionaries if you know you have 100 keys.
Determine if char is a num or letter
C99 standard on c >= '0' && c <= '9'
c >= '0' && c <= '9'
(mentioned in another answer) works because C99 N1256 standard draft 5.2.1 "Character sets" says:
In both the source and execution basic character sets, the
value of each character after 0 in the above list of decimal digits shall be one greater than the value of the previous.
ASCII is not guaranteed however.
What is a stack pointer used for in microprocessors?
The stack pointer stores the address of the most recent entry that was pushed onto the stack.
To push a value onto the stack, the stack pointer is incremented to point to the next physical memory address, and the new value is copied to that address in memory.
To pop a value from the stack, the value is copied from the address of the stack pointer, and the stack pointer is decremented, pointing it to the next available item in the stack.
The most typical use of a hardware stack is to store the return address of a subroutine call. When the subroutine is finished executing, the return address is popped off the top of the stack and placed in the Program Counter register, causing the processor to resume execution at the next instruction following the call to the subroutine.
http://en.wikipedia.org/wiki/Stack_%28data_structure%29#Hardware_stacks
What's in an Eclipse .classpath/.project file?
Complete reference is not available for the mentioned files, as they are extensible by various plug-ins.
Basically, .project files store project-settings, such as builder and project nature settings, while .classpath files define the classpath to use during running. The classpath files contains src and target entries that correspond with folders in the project; the con entries are used to describe some kind of "virtual" entries, such as the JVM libs or in case of eclipse plug-ins dependencies (normal Java project dependencies are displayed differently, using a special src entry).
Install NuGet via PowerShell script
None of the above solutions worked for me, I found an article that explained the issue. The security protocols on the system were deprecated and therefore displayed an error message that no match was found for the ProviderPackage.
Here is a the basic steps for upgrading your security protocols:
Run both cmdlets to set .NET Framework strong cryptography registry keys. After that, restart PowerShell and check if the security protocol TLS 1.2 is added. As of last, install the PowerShellGet module.
The first cmdlet is to set strong cryptography on 64 bit .Net Framework (version 4 and above).
[PS] C:\>Set-ItemProperty -Path 'HKLM:\SOFTWARE\Wow6432Node\Microsoft\.NetFramework\v4.0.30319' -Name 'SchUseStrongCrypto' -Value '1' -Type DWord
1
[PS] C:\>Set-ItemProperty -Path 'HKLM:\SOFTWARE\Wow6432Node\Microsoft\.NetFramework\v4.0.30319' -Name 'SchUseStrongCrypto' -Value '1' -Type DWord
The second cmdlet is to set strong cryptography on 32 bit .Net Framework (version 4 and above).
[PS] C:\>Set-ItemProperty -Path 'HKLM:\SOFTWARE\Microsoft\.NetFramework\v4.0.30319' -Name 'SchUseStrongCrypto' -Value '1' -Type DWord
1
[PS] C:\>Set-ItemProperty -Path 'HKLM:\SOFTWARE\Microsoft\.NetFramework\v4.0.30319' -Name 'SchUseStrongCrypto' -Value '1' -Type DWord
Restart Powershell and check for supported security protocols.
[PS] C:\>[Net.ServicePointManager]::SecurityProtocol
Tls, Tls11, Tls12
1
2
[PS] C:\>[Net.ServicePointManager]::SecurityProtocol
Tls, Tls11, Tls12
Run the command Install-Module PowershellGet -Force and press Y to install NuGet provider, follow with Enter.
[PS] C:\>Install-Module PowershellGet -Force
NuGet provider is required to continue
PowerShellGet requires NuGet provider version '2.8.5.201' or newer to interact with NuGet-based repositories. The NuGet provider must be available in 'C:\Program Files\PackageManagement\ProviderAssemblies' or
'C:\Users\administrator.EXOIP\AppData\Local\PackageManagement\ProviderAssemblies'. You can also install the NuGet provider by running 'Install-PackageProvider -Name NuGet -MinimumVersion 2.8.5.201 -Force'. Do you want PowerShellGet to install
and import the NuGet provider now?
[Y] Yes [N] No [S] Suspend [?] Help (default is "Y"): Y
[PS] C:\>Install-Module PowershellGet -Force
NuGet provider is required to continue
PowerShellGet requires NuGet provider version '2.8.5.201' or newer to interact with NuGet-based repositories. The NuGet provider must be available in 'C:\Program Files\PackageManagement\ProviderAssemblies' or
'C:\Users\administrator.EXOIP\AppData\Local\PackageManagement\ProviderAssemblies'. You can also install the NuGet provider by running 'Install-PackageProvider -Name NuGet -MinimumVersion 2.8.5.201 -Force'. Do you want PowerShellGet to install
and import the NuGet provider now?
[Y] Yes [N] No [S] Suspend [?] Help (default is "Y"): Y
How to print HTML content on click of a button, but not the page?
Here is a pure css version
_x000D_
_x000D_
.example-print {_x000D_
display: none;_x000D_
}_x000D_
@media print {_x000D_
.example-screen {_x000D_
display: none;_x000D_
}_x000D_
.example-print {_x000D_
display: block;_x000D_
}_x000D_
}
_x000D_
<div class="example-screen">You only see me in the browser</div>_x000D_
_x000D_
<div class="example-print">You only see me in the print</div>
_x000D_
_x000D_
_x000D_
Difference Between $.getJSON() and $.ajax() in jQuery
.getJson is simply a wrapper around .ajax but it provides a simpler method signature as some of the settings are defaulted e.g dataType to json, type to get etc
N.B .load, .get and .post are also simple wrappers around the .ajax method.
How to round up the result of integer division?
Alternative to remove branching in testing for zero:
int pageCount = (records + recordsPerPage - 1) / recordsPerPage * (records != 0);
Not sure if this will work in C#, should do in C/C++.
How to restore to a different database in sql server?
You can create a new db then use the "Restore Wizard" enabling the Overwrite option or;
View the content;
RESTORE FILELISTONLY FROM DISK='c:\your.bak'
note the logical names of the .mdf & .ldf from the results, then;
RESTORE DATABASE MyTempCopy FROM DISK='c:\your.bak'
WITH
MOVE 'LogicalNameForTheMDF' TO 'c:\MyTempCopy.mdf',
MOVE 'LogicalNameForTheLDF' TO 'c:\MyTempCopy_log.ldf'
To create the database MyTempCopy
with the contents of your.bak
.
Example (restores a backup of a db called 'creditline' to 'MyTempCopy';
RESTORE FILELISTONLY FROM DISK='e:\mssql\backup\creditline.bak'
>LogicalName
>--------------
>CreditLine
>CreditLine_log
RESTORE DATABASE MyTempCopy FROM DISK='e:\mssql\backup\creditline.bak'
WITH
MOVE 'CreditLine' TO 'e:\mssql\MyTempCopy.mdf',
MOVE 'CreditLine_log' TO 'e:\mssql\MyTempCopy_log.ldf'
>RESTORE DATABASE successfully processed 186 pages in 0.010 seconds (144.970 MB/sec).
How can I add a volume to an existing Docker container?
A note for using Docker Windows containers after I had to look for this problem for a long time!
Condiditions:
- Windows 10
- Docker Desktop (latest version)
- using Docker Windows Container for image microsoft/mssql-server-windows-developer
Problem:
- I wanted to mount a host dictionary into my windows container.
Solution as partially discripted here:
docker run -d -p 1433:1433 -e sa_password=<STRONG_PASSWORD> -e ACCEPT_EULA=Y microsoft/mssql-server-windows-developer
- go to command shell in container
docker exec -it <CONTAINERID> cmd.exe
mkdir DirForMount
docker container stop <CONTAINERID>
docker commit <CONTAINERID> <NEWIMAGENAME>
docker container rm <CONTAINERID>
- create new container with new image and volume mounting
docker run -d -p 1433:1433 -e sa_password=<STRONG_PASSWORD> -e ACCEPT_EULA=Y -v C:\DirToMount:C:\DirForMount <NEWIMAGENAME>
After this i solved this problem on docker windows containers.
UITableViewCell, show delete button on swipe
Swift 2.2 :
override func tableView(tableView: UITableView, canEditRowAtIndexPath indexPath: NSIndexPath) -> Bool {
return true
}
override func tableView(tableView: UITableView,
editActionsForRowAtIndexPath indexPath: NSIndexPath) -> [UITableViewRowAction]? {
let delete = UITableViewRowAction(style: UITableViewRowActionStyle.Default, title: "DELETE"){(UITableViewRowAction,NSIndexPath) -> Void in
print("Your action when user pressed delete")
}
let edit = UITableViewRowAction(style: UITableViewRowActionStyle.Normal, title: "EDIT"){(UITableViewRowAction,NSIndexPath) -> Void in
print("Your action when user pressed edit")
}
return [delete, block]
}
How do I get Fiddler to stop ignoring traffic to localhost?
For Fiddler to capture traffic from localhost on local IIS, there are 3 steps (It worked on my computer):
- Click Tools > Fiddler Options. Ensure Allow remote clients to connect is checked. Close Fiddler.
- Create a new DWORD named ReverseProxyForPort inside KEY_CURRENT_USER\SOFTWARE\Microsoft\Fiddler2.
Set the DWORD to port 80 (choose decimal here). Restart Fiddler.
- Add port 8888 to the addresses defined in your client. For example localhost:8888/MyService/WebAPI/v1/
Cannot read property 'style' of undefined -- Uncaught Type Error
It's currently working, I've just changed the operator >
in order to work in the snippet, take a look:
_x000D_
_x000D_
window.onload = function() {_x000D_
_x000D_
if (window.location.href.indexOf("test") <= -1) {_x000D_
var search_span = document.getElementsByClassName("securitySearchQuery");_x000D_
search_span[0].style.color = "blue";_x000D_
search_span[0].style.fontWeight = "bold";_x000D_
search_span[0].style.fontSize = "40px";_x000D_
_x000D_
}_x000D_
_x000D_
}
_x000D_
<h1 class="keyword-title">Search results for<span class="securitySearchQuery"> "hi".</span></h1>
_x000D_
_x000D_
_x000D_
Difference between HashMap, LinkedHashMap and TreeMap
Just some more input from my own experience with maps, on when I would use each one:
- HashMap - Most useful when looking for a best-performance (fast) implementation.
- TreeMap (SortedMap interface) - Most useful when I'm concerned with being able to sort or iterate over the keys in a particular order that I define.
- LinkedHashMap - Combines advantages of guaranteed ordering from TreeMap without the increased cost of maintaining the TreeMap. (It is almost as fast as the HashMap). In particular, the LinkedHashMap also provides a great starting point for creating a Cache object by overriding the
removeEldestEntry()
method. This lets you create a Cache object that can expire data using some criteria that you define.
How to set a hidden value in Razor
While I would have gone with Piotr's answer (because it's all in one line), I was surprised that your sample is closer to your solution than you think. From what you have, you simply assign the model value before you use the Html helper method.
@{Model.RequiredProperty = "default";}
@Html.HiddenFor(model => model.RequiredProperty)
What is "entropy and information gain"?
When I was implementing an algorithm to calculate the entropy of an image I found these links, see here and here.
This is the pseudo-code I used, you'll need to adapt it to work with text rather than images but the principles should be the same.
//Loop over image array elements and count occurrences of each possible
//pixel to pixel difference value. Store these values in prob_array
for j = 0, ysize-1 do $
for i = 0, xsize-2 do begin
diff = array(i+1,j) - array(i,j)
if diff lt (array_size+1)/2 and diff gt -(array_size+1)/2 then begin
prob_array(diff+(array_size-1)/2) = prob_array(diff+(array_size-1)/2) + 1
endif
endfor
//Convert values in prob_array to probabilities and compute entropy
n = total(prob_array)
entrop = 0
for i = 0, array_size-1 do begin
prob_array(i) = prob_array(i)/n
//Base 2 log of x is Ln(x)/Ln(2). Take Ln of array element
//here and divide final sum by Ln(2)
if prob_array(i) ne 0 then begin
entrop = entrop - prob_array(i)*alog(prob_array(i))
endif
endfor
entrop = entrop/alog(2)
I got this code from somewhere, but I can't dig out the link.
git add remote branch
Here is the complete process to create a local repo and push the changes to new remote branch
Creating local repository:-
Initially user may have created the local git repository.
$ git init
:- This will make the local folder as Git repository,
Link the remote branch:-
Now challenge is associate the local git repository with remote master branch.
$ git remote add RepoName RepoURL
usage: git remote add []
Test the Remote
$ git remote show
--->Display the remote name
$ git remote -v
--->Display the remote branches
Now Push to remote
$git add .
----> Add all the files and folder as git staged'
$git commit -m "Your Commit Message"
- - - >Commit the message
$git push
- - - - >Push the changes to the upstream
How to remove foreign key constraint in sql server?
Drop all the foreign keys of a table:
USE [Database_Name]
DECLARE @FOREIGN_KEY_NAME VARCHAR(100)
DECLARE FOREIGN_KEY_CURSOR CURSOR FOR
SELECT name FOREIGN_KEY_NAME FROM sys.foreign_keys WHERE parent_object_id = (SELECT object_id FROM sys.objects WHERE name = 'Table_Name' AND TYPE = 'U')
OPEN FOREIGN_KEY_CURSOR
----------------------------------------------------------
FETCH NEXT FROM FOREIGN_KEY_CURSOR INTO @FOREIGN_KEY_NAME
WHILE @@FETCH_STATUS = 0
BEGIN
DECLARE @DROP_COMMAND NVARCHAR(150) = 'ALTER TABLE Table_Name DROP CONSTRAINT' + ' ' + @FOREIGN_KEY_NAME
EXECUTE Sp_executesql @DROP_COMMAND
FETCH NEXT FROM FOREIGN_KEY_CURSOR INTO @FOREIGN_KEY_NAME
END
-----------------------------------------------------------------------------------------------------------------
CLOSE FOREIGN_KEY_CURSOR
DEALLOCATE FOREIGN_KEY_CURSOR
How to initialize a static array?
If you are creating an array then there is no difference, however, the following is neater:
String[] suit = {
"spades",
"hearts",
"diamonds",
"clubs"
};
But, if you want to pass an array into a method you have to call it like this:
myMethod(new String[] {"spades", "hearts"});
myMethod({"spades", "hearts"}); //won't compile!
Find (and kill) process locking port 3000 on Mac
TL;DR:
lsof -ti tcp:3000 -sTCP:LISTEN | xargs kill
If you're in a situation where there are both clients and servers using the port, e.g.:
$ lsof -i tcp:3000
COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME
node 2043 benjiegillam 21u IPv4 0xb1b4330c68e5ad61 0t0 TCP localhost:3000->localhost:52557 (ESTABLISHED)
node 2043 benjiegillam 22u IPv4 0xb1b4330c8d393021 0t0 TCP localhost:3000->localhost:52344 (ESTABLISHED)
node 2043 benjiegillam 25u IPv4 0xb1b4330c8eaf16c1 0t0 TCP localhost:3000 (LISTEN)
Google 99004 benjiegillam 125u IPv4 0xb1b4330c8bb05021 0t0 TCP localhost:52557->localhost:3000 (ESTABLISHED)
Google 99004 benjiegillam 216u IPv4 0xb1b4330c8e5ea6c1 0t0 TCP localhost:52344->localhost:3000 (ESTABLISHED)
then you probably don't want to kill both.
In this situation you can use -sTCP:LISTEN
to only show the pid of processes that are listening. Combining this with the -t
terse format you can automatically kill the process:
lsof -ti tcp:3000 -sTCP:LISTEN | xargs kill
Session timeout in ASP.NET
Are you using Forms authentication?
Forms authentication uses it own value for timeout (30 min. by default). A forms authentication timeout will send the user to the login page with the session still active. This may look like the behavior your app gives when session times out making it easy to confuse one with the other.
<system.web>
<authentication mode="Forms">
<forms timeout="50"/>
</authentication>
<sessionState timeout="60" />
</system.web>
Setting the forms timeout to something less than the session timeout can give the user a window in which to log back in without losing any session data.
How to get a reference to an iframe's window object inside iframe's onload handler created from parent window
You're declaring everything in the parent page. So the references to window
and document
are to the parent page's. If you want to do stuff to the iframe
's, use iframe || iframe.contentWindow
to access its window
, and iframe.contentDocument || iframe.contentWindow.document
to access its document
.
There's a word for what's happening, possibly "lexical scope": What is lexical scope?
The only context of a scope is this. And in your example, the owner of the method is doc
, which is the iframe
's document
. Other than that, anything that's accessed in this function that uses known objects are the parent's (if not declared in the function). It would be a different story if the function were declared in a different place, but it's declared in the parent page.
This is how I would write it:
(function () {
var dom, win, doc, where, iframe;
iframe = document.createElement('iframe');
iframe.src = "javascript:false";
where = document.getElementsByTagName('script')[0];
where.parentNode.insertBefore(iframe, where);
win = iframe.contentWindow || iframe;
doc = iframe.contentDocument || iframe.contentWindow.document;
doc.open();
doc._l = (function (w, d) {
return function () {
w.vanishing_global = new Date().getTime();
var js = d.createElement("script");
js.src = 'test-vanishing-global.js?' + w.vanishing_global;
w.name = "foobar";
d.foobar = "foobar:" + Math.random();
d.foobar = "barfoo:" + Math.random();
d.body.appendChild(js);
};
})(win, doc);
doc.write('<body onload="document._l();"></body>');
doc.close();
})();
The aliasing of win
and doc
as w
and d
aren't necessary, it just might make it less confusing because of the misunderstanding of scopes. This way, they are parameters and you have to reference them to access the iframe
's stuff. If you want to access the parent's, you still use window
and document
.
I'm not sure what the implications are of adding methods to a document
(doc
in this case), but it might make more sense to set the _l
method on win
. That way, things can be run without a prefix...such as <body onload="_l();"></body>
What is the difference between display: inline and display: inline-block?
One thing not mentioned in answers is inline element can break among lines while inline-block can't (and obviously block)! So inline elements can be useful to style sentences of text and blocks inside them, but as they can't be padded you can use line-height instead.
_x000D_
_x000D_
<div style="width: 350px">_x000D_
Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua._x000D_
<div style="display: inline; background: #F00; color: #FFF">_x000D_
Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat._x000D_
</div>_x000D_
Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum._x000D_
</div>_x000D_
<hr/>_x000D_
<div style="width: 350px">_x000D_
Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua._x000D_
<div style="display: inline-block; background: #F00; color: #FFF">_x000D_
Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat._x000D_
</div>_x000D_
Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum._x000D_
</div>
_x000D_
_x000D_
_x000D_
Checking if a file is a directory or just a file
You can call the stat() function and use the S_ISREG()
macro on the st_mode
field of the stat structure in order to determine if your path points to a regular file:
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
int is_regular_file(const char *path)
{
struct stat path_stat;
stat(path, &path_stat);
return S_ISREG(path_stat.st_mode);
}
Note that there are other file types besides regular and directory, like devices, pipes, symbolic links, sockets, etc. You might want to take those into account.
git pull remote branch cannot find remote ref
This error happens because the local repository can't identify the remote branch at first time. So you need to do it first. It can be done using following commands:
git remote add origin 'url_of_your_github_project'
git push -u origin master
Auto refresh page every 30 seconds
Use setInterval
instead of setTimeout
. Though in this case either will be fine but setTimeout
inherently triggers only once setInterval
continues indefinitely.
<script language="javascript">
setInterval(function(){
window.location.reload(1);
}, 30000);
</script>
Intel's HAXM equivalent for AMD on Windows OS
Posting a new answer since it is 2019.
TLDR: AMD is now supported on both Windows and Linux via WHPX and yes, Genymotion is faster as it is using x86 architecture virtualization.
From the Android docs (January 2019):
Though we recommend using HAXM on Windows, it is possible to use
Windows Hypervisor Platform (WHPX) with the emulator. You should use
WHPX with the emulator if you are using an AMD CPU or if you need to
use Hyper-V at the same time.
To use WHPX acceleration on Windows, you must enable the Windows
Hypervisor Platform option in the Turn Windows features on or off
dialog box. For changes to this option to take effect, restart your
computer.
Additionally, the following changes must be made in the BIOS settings:
Intel CPU: VT-x must be enabled. AMD CPU: Virtualization or SVM must
be enabled.
Diff from 2016:
Virtualization extension requirements
Before attempting to use acceleration, you should first determine if
your CPU supports one of the following virtualization extensions
technologies:
- Intel Virtualization Technology (VT, VT-x, vmx) extensions
- AMD Virtualization (AMD-V, SVM) extensions
(only supported for Linux)
Most modern computers do. If you use an older computer and you're not
sure, consult the specifications from the manufacturer of your CPU to
determine if it supports virtualization extensions. If your CPU
doesn't support one of these virtualization technologies, then you
can't use VM acceleration.
Virtualization extensions are typically enabled through your computer BIOS and are frequently turned off by default. Check the documentation
for your motherboard to find out how to enable virtualization
extensions.
Python List & for-each access (Find/Replace in built-in list)
Answering this has been good, as the comments have led to an improvement in my own understanding of Python variables.
As noted in the comments, when you loop over a list with something like for member in my_list
the member
variable is bound to each successive list element. However, re-assigning that variable within the loop doesn't directly affect the list itself. For example, this code won't change the list:
my_list = [1,2,3]
for member in my_list:
member = 42
print my_list
Output:
[1, 2, 3]
If you want to change a list containing immutable types, you need to do something like:
my_list = [1,2,3]
for ndx, member in enumerate(my_list):
my_list[ndx] += 42
print my_list
Output:
[43, 44, 45]
If your list contains mutable objects, you can modify the current member
object directly:
class C:
def __init__(self, n):
self.num = n
def __repr__(self):
return str(self.num)
my_list = [C(i) for i in xrange(3)]
for member in my_list:
member.num += 42
print my_list
[42, 43, 44]
Note that you are still not changing the list, simply modifying the objects in the list.
You might benefit from reading Naming and Binding.
Getting full URL of action in ASP.NET MVC
As Paddy mentioned: if you use an overload of UrlHelper.Action()
that explicitly specifies the protocol to use, the generated URL will be absolute and fully qualified instead of being relative.
I wrote a blog post called How to build absolute action URLs using the UrlHelper class in which I suggest to write a custom extension method for the sake of readability:
/// <summary>
/// Generates a fully qualified URL to an action method by using
/// the specified action name, controller name and route values.
/// </summary>
/// <param name="url">The URL helper.</param>
/// <param name="actionName">The name of the action method.</param>
/// <param name="controllerName">The name of the controller.</param>
/// <param name="routeValues">The route values.</param>
/// <returns>The absolute URL.</returns>
public static string AbsoluteAction(this UrlHelper url,
string actionName, string controllerName, object routeValues = null)
{
string scheme = url.RequestContext.HttpContext.Request.Url.Scheme;
return url.Action(actionName, controllerName, routeValues, scheme);
}
You can then simply use it like that in your view:
@Url.AbsoluteAction("Action", "Controller")
get current url in twig template?
{{ path(app.request.attributes.get('_route'),
app.request.attributes.get('_route_params')) }}
If you want to read it into a view variable:
{% set currentPath = path(app.request.attributes.get('_route'),
app.request.attributes.get('_route_params')) %}
The app
global view variable contains all sorts of useful shortcuts, such as app.session
and app.security.token.user
, that reference the services you might use in a controller.
Using subprocess to run Python script on Windows
Just found sys.executable
- the full path to the current Python executable, which can be used to run the script (instead of relying on the shbang, which obviously doesn't work on Windows)
import sys
import subprocess
theproc = subprocess.Popen([sys.executable, "myscript.py"])
theproc.communicate()
How to remove elements/nodes from angular.js array
My solution to this (which hasn't caused any performance issues):
- Extend the array object with a method remove (i'm sure you will need it more than just one time):
Array.prototype.remove = function(from, to) {
var rest = this.slice((to || from) + 1 || this.length);
this.length = from < 0 ? this.length + from : from;
return this.push.apply(this, rest);
};
I'm using it in all of my projects and credits go to John Resig John Resig's Site
- Using forEach and a basic check:
$scope.items.forEach(function(element, index, array){
if(element.name === 'ted'){
$scope.items.remove(index);
}
});
At the end the $digest will be fired in angularjs and my UI is updated immediately without any recognizable lag.
C: scanf to array
Use
scanf("%d", &array[0]);
and use ==
for comparision instead of =
prevent property from being serialized in web API
I'm late to the game, but an anonymous objects would do the trick:
[HttpGet]
public HttpResponseMessage Me(string hash)
{
HttpResponseMessage httpResponseMessage;
List<Something> somethings = ...
var returnObjects = somethings.Select(x => new {
Id = x.Id,
OtherField = x.OtherField
});
httpResponseMessage = Request.CreateResponse(HttpStatusCode.OK,
new { result = true, somethings = returnObjects });
return httpResponseMessage;
}
Proper way to concatenate variable strings
Good question. But I think there is no good answer which fits your criteria. The best I can think of is to use an extra vars file.
A task like this:
- include_vars: concat.yml
And in concat.yml
you have your definition:
newvar: "{{ var1 }}-{{ var2 }}-{{ var3 }}"
How to remove trailing and leading whitespace for user-provided input in a batch file?
@echo off
setlocal EnableDelayedExpansion
set S= This is a test
echo %S%.
for /f "tokens=* delims= " %%a in ('echo %S%') do (set b=%%a & set b=!b: =! & echo !b!)
endlocal & goto :EOF
or
@echo off
setlocal EnableDelayedExpansion
set S= This is a test
echo %S%.
for /f "tokens=* delims= " %%a in ('echo %S%') do (set b=%%a & set b=!b: =_! & echo !b!)
endlocal & goto :EOF
Building a complete online payment gateway like Paypal
What you're talking about is becoming a payment service provider. I have been there and done that. It was a lot easier about 10 years ago than it is now, but if you have a phenomenal amount of time, money and patience available, it is still possible.
You will need to contact an acquiring bank. You didnt say what region of the world you are in, but by this I dont mean a local bank branch. Each major bank will generally have a separate card acquiring arm. So here in the UK we have (eg) Natwest bank, which uses Streamline (or Worldpay) as its acquiring arm. In total even though we have scores of major banks, they all end up using one of five or so card acquirers.
Happily, all UK card acquirers use a standard protocol for communication of authorisation requests, and end of day settlement. You will find minor quirks where some acquiring banks support some features and have slightly different syntax, but the differences are fairly minor. The UK standards are published by the Association for Payment Clearing Services (APACS) (which is now known as the UKPA). The standards are still commonly referred to as APACS 30 (authorization) and APACS 29 (settlement), but are now formally known as APACS 70 (books 1 through 7).
Although the APACS standard is widely supported across the UK (Amex and Discover accept messages in this format too) it is not used in other countries - each country has it's own - for example: Carte Bancaire in France, CartaSi in Italy, Sistema 4B in Spain, Dankort in Denmark etc. An effort is under way to unify the protocols across Europe - see EPAS.org
Communicating with the acquiring bank can be done a number of ways. Again though, it will depend on your region. In the UK (and most of Europe) we have one communications gateway that provides connectivity to all the major acquirers, they are called TNS and there are dozens of ways of communicating through them to the acquiring bank, from dialup 9600 baud modems, ISDN, HTTPS, VPN or dedicated line. Ultimately the authorisation request will be converted to X25 protocol, which is the protocol used by these acquiring banks when communicating with each other.
In summary then: it all depends on your region.
- Contact a major bank and try to get through to their card acquiring arm.
- Explain that you're setting up as a payment service provider, and request details on comms format for authorization requests and end of day settlement files
- Set up a test merchant account and develop auth/settlement software and go through the accreditation process. Most acquirers help you through this process for free, but when you want to register as an accredited PSP some will request a fee.
- you will need to comply with some regulations too, for example you may need to register as a payment institution
Once you are registered and accredited you'll then be able to accept customers and set up merchant accounts on behalf of the bank/s you're accredited against (bearing in mind that each acquirer will generally support multiple banks). Rinse and repeat with other acquirers as you see necessary.
Beyond that you have lots of other issues, mainly dealing with PCI-DSS. Thats a whole other topic and there are already some q&a's on this site regarding that. Like I say, its a phenomenal undertaking - most likely a multi-year project even for a reasonably sized team, but its certainly possible.
Error importing Seaborn module in Python
I have the same problem and I solved it and the explanation is as follow:
If the Seaborn package is not installed in anaconda, you will not be able to update it, namely,
if in the Terminal we type: conda update seaborn
it will fail showing:
"PackageNotFoundError: Package not found: 'seaborn' Package 'seaborn' is not installed in /Users/yifan/anaconda"
Thus we need to install seaborn in anaconda first by typing in Terminal:
conda install -c https://conda.anaconda.org/anaconda seaborn
Then the seaborn will be fetched and installed in the environment of anaconda, namely in my case, /Users/yifan/anaconda
Once this installation is done, we will be able to import seaborn in python.
Side note, to check and list all discoverable environments where python is installed in anaconda, type in Terminal:
conda info --envs
How to call an async method from a getter or setter?
There is no technical reason that async
properties are not allowed in C#. It was a purposeful design decision, because "asynchronous properties" is an oxymoron.
Properties should return current values; they should not be kicking off background operations.
Usually, when someone wants an "asynchronous property", what they really want is one of these:
- An asynchronous method that returns a value. In this case, change the property to an
async
method.
- A value that can be used in data-binding but must be calculated/retrieved asynchronously. In this case, either use an
async
factory method for the containing object or use an async InitAsync()
method. The data-bound value will be default(T)
until the value is calculated/retrieved.
- A value that is expensive to create, but should be cached for future use. In this case, use
AsyncLazy
from my blog or AsyncEx library. This will give you an await
able property.
Update: I cover asynchronous properties in one of my recent "async OOP" blog posts.
What is the difference between a process and a thread?
Both threads and processes are atomic units of OS resource allocation (i.e. there is a concurrency model describing how CPU time is divided between them, and the model of owning other OS resources). There is a difference in:
- Shared resources (threads are sharing memory by definition, they do not own anything except stack and local variables; processes could also share memory, but there is a separate mechanism for that, maintained by OS)
- Allocation space (kernel space for processes vs. user space for threads)
Greg Hewgill above was correct about the Erlang meaning of the word "process", and here there's a discussion of why Erlang could do processes lightweight.
Correct location of openssl.cnf file
/usr/local/ssl/openssl.cnf
This is a local installation. You downloaded and built OpenSSL taking the default prefix
, of you configured with ./config --prefix=/usr/local/ssl
or ./config --openssldir=/usr/local/ssl
.
You will use this if you use the OpenSSL in /usr/local/ssl/bin
. That is, /usr/local/ssl/openssl.cnf
will be used when you issue:
/usr/local/ssl/bin/openssl s_client -connect localhost:443 -tls1 -servername localhost
/usr/lib/ssl/openssl.cnf
This is where Ubuntu places openssl.cnf
for the OpenSSL they provide.
You will use this if you use the OpenSSL in /usr/bin
. That is, /usr/lib/ssl/openssl.cnf
will be used when you issue:
openssl s_client -connect localhost:443 -tls1 -servername localhost
/etc/ssl/openssl.cnf
I don't know when this is used. The stuff in /etc/ssl
is usually certificates and private keys, and it sometimes contains a copy of openssl.cnf
. But I've never seen it used for anything.
Which is the main/correct one that I should use to make changes?
From the sounds of it, you should probably add the engine to /usr/lib/ssl/openssl.cnf
. That ensures most "off the shelf" gear will use the new engine.
After you do that, add it to /usr/local/ssl/openssl.cnf
also because copy/paste is easy.
Here's how to see which openssl.cnf
directory is associated with a OpenSSL installation. The library and programs look for openssl.cnf
in OPENSSLDIR
. OPENSSLDIR
is a configure option, and its set with --openssldir
.
I'm on a MacBook with 3 different OpenSSL's (Apple's, MacPort's and the one I build):
# Apple
$ /usr/bin/openssl version -a | grep OPENSSLDIR
OPENSSLDIR: "/System/Library/OpenSSL"
# MacPorts
$ /opt/local/bin/openssl version -a | grep OPENSSLDIR
OPENSSLDIR: "/opt/local/etc/openssl"
# My build of OpenSSL
$ openssl version -a | grep OPENSSLDIR
OPENSSLDIR: "/usr/local/ssl/darwin"
I have an Ubuntu system and I have installed openssl.
Just bike shedding, but be careful of Ubuntu's version of OpenSSL. It disables TLSv1.1 and TLSv1.2, so you will only have clients capable of older cipher suites; and you will not be able to use newer ciphers like AES/CTR (to replace RC4) and elliptic curve gear (like ECDHE_ECDSA_*
and ECDHE_RSA_*
). See Ubuntu 12.04 LTS: OpenSSL downlevel version is 1.0.0, and does not support TLS 1.2 in Launchpad.
EDIT: Ubuntu enabled TLS 1.1 and TLS 1.2 recently. See Comment 17 on the bug report.
How to search for an element in a golang slice
You can use sort.Slice()
plus sort.Search()
type Person struct {
Name string
}
func main() {
crowd := []Person{{"Zoey"}, {"Anna"}, {"Benni"}, {"Chris"}}
sort.Slice(crowd, func(i, j int) bool {
return crowd[i].Name <= crowd[j].Name
})
needle := "Benni"
idx := sort.Search(len(crowd), func(i int) bool {
return string(crowd[i].Name) >= needle
})
if crowd[idx].Name == needle {
fmt.Println("Found:", idx, crowd[idx])
} else {
fmt.Println("Found noting: ", idx)
}
}
See: https://play.golang.org/p/47OPrjKb0g_c
Correct way to write line to file?
since others have answered how to do it, I'll answer how it happens line by line.
with FileOpenerCM('file.txt') as fp: # is equal to "with open('file.txt') as fp:"
fp.write('dummy text')
this is a so-called context manager
, anything that comes with a with
block is a context manager. so let's see how this happens under the hood.
class FileOpenerCM:
def __init__(self, file, mode='w'):
self.file = open(file, mode)
def __enter__(self):
return self.file
def __exit__(self, exc_type, exc_value, exc_traceback):
self.file.close()
the first method __init__
is (as you all know) the initialization method of an object. whenever an object is created obj.__init__
is definitely called. and that's the place where you put your all the init kinda code.
the second method __enter__
is a bit interesting. some of you might not have seen it because it is a specific method for context managers. what it returns is the value to be assigned to the variable after the as
keyword. in our case, fp
.
the last method is the method to run after an error is captured or if the code exits the with block. exc_type
, exc_value
, exc_traceback
variables are the variables that hold the values of the errors that occurred inside with block. for example,
exc_type: TypeError
exc_value: unsupported operand type(s) for +: 'int' and 'str
exc_traceback: <traceback object at 0x6af8ee10bc4d>
from the first two variables, you can get info enough info about the error. honestly, I don't know the use of the third variable, but for me, the first two are enough. if you want to do more research on context managers surely you can do it and note that writing classes are not the only way to write context managers. with contextlib you can write context managers through functions(actually generators) as well. it's totally up to you to have a look at it. you can surely try
generator functions with contextlib but as I see classes are much cleaner.
Configuration with name 'default' not found. Android Studio
For one, it doesn't do good to have more than one settings.gradle file -- it only looks at the top-level one.
When you get this "Configuration with name 'default' not found" error, it's really confusing, but what it means is that Gradle is looking for a module (or a build.gradle) file someplace, and it's not finding it. In your case, you have this in your settings.gradle file:
include ':libraries:Android-Bootstrap',':Android-Bootstrap'
which is making Gradle look for a library at FTPBackup/libraries/Android-Bootstrap. If you're on a case-sensitive filesystem (and you haven't mistyped Libraries in your question when you meant libraries), it may not find FTPBackup/Libraries/Android-Bootstrap because of the case difference. It's also looking for another library at FTPBackup/Android-Bootstrap, and it's definitely not going to find one because that directory isn't there.
This should work:
include ':Libraries:Android-Bootstrap'
You need the same case-sensitive spec in your dependencies
block:
compile project (':Libraries:Android-Bootstrap')
How to validate an email address in JavaScript
Regex update 2018! try this
let val = '[email protected]';
if(/^[a-z0-9][a-z0-9-_\.]+@([a-z]|[a-z0-9]?[a-z0-9-]+[a-z0-9])\.[a-z0-9]{2,10}(?:\.[a-z]{2,10})?$/.test(val)) {
console.log('passed');
}
typscript version complete
//
export const emailValid = (val:string):boolean => /^[a-z0-9][a-z0-9-_\.]+@([a-z]|[a-z0-9]?[a-z0-9-]+[a-z0-9])\.[a-z0-9]{2,10}(?:\.[a-z]{2,10})?$/.test(val);
more info https://git.io/vhEfc
Initialize/reset struct to zero/null
Better than all above is ever to use Standard C specification for struct initialization:
struct StructType structVar = {0};
Here are all bits zero (ever).
Type of expression is ambiguous without more context Swift
As theEye's answer it is not an answer to this question, but as I also came here looking for the error im posting my case as others might find this also useful:
I got this error message when I was by error trying to calculate a value of two different types.
In my case I was trying to divide a CGFloat
by a Double
Select Last Row in the Table
To get last record details
Model::all()->last();
or
Model::orderBy('id', 'desc')->first();
To get last record id
Model::all()->last()->id;
or
Model::orderBy('id', 'desc')->first()->id;
How to read/write arbitrary bits in C/C++
You have to do a shift and mask (AND) operation.
Let b be any byte and p be the index (>= 0) of the bit from which you want to take n bits (>= 1).
First you have to shift right b by p times:
x = b >> p;
Second you have to mask the result with n ones:
mask = (1 << n) - 1;
y = x & mask;
You can put everything in a macro:
#define TAKE_N_BITS_FROM(b, p, n) ((b) >> (p)) & ((1 << (n)) - 1)
ALTER TABLE to add a composite primary key
It`s definitely better to use COMPOSITE UNIQUE KEY, as @GranadaCoder offered, a little bit tricky example though:
ALTER IGNORE TABLE table_name ADD UNIQUES INDEX idx_name(some_id, another_id, one_more_id);
How many significant digits do floats and doubles have in java?
float: 32 bits (4 bytes) where 23 bits are used for the mantissa (about 7 decimal digits). 8 bits are used for the exponent, so a float can “move” the decimal point to the right or to the left using those 8 bits. Doing so avoids storing lots of zeros in the mantissa as in 0.0000003 (3 × 10-7) or 3000000 (3 × 107). There is 1 bit used as the sign bit.
double: 64 bits (8 bytes) where 52 bits are used for the mantissa (about 16 decimal digits). 11 bits are used for the exponent and 1 bit is the sign bit.
Since we are using binary (only 0 and 1), one bit in the mantissa is implicitly 1 (both float and double use this trick) when the number is non-zero.
Also, since everything is in binary (mantissa and exponents) the conversions to decimal numbers are usually not exact. Numbers like 0.5, 0.25, 0.75, 0.125 are stored exactly, but 0.1 is not. As others have said, if you need to store cents precisely, do not use float or double, use int, long, BigInteger or BigDecimal.
Sources:
http://en.wikipedia.org/wiki/Floating_point#IEEE_754:_floating_point_in_modern_computers
http://en.wikipedia.org/wiki/Binary64
http://en.wikipedia.org/wiki/Binary32
Curly braces in string in PHP
Example:
$number = 4;
print "You have the {$number}th edition book";
//output: "You have the 4th edition book";
Without curly braces PHP would try to find a variable named $numberth
, that doesn't exist!
Chrome, Javascript, window.open in new tab
You can't directly control this, because it's an option controlled by Internet Explorer users.
Opening pages using Window.open with a different window name will open in a new browser window like a popup, OR open in a new tab, if the user configured the browser to do so.
EDIT:
A more detailed explanation:
1. In modern browsers, window.open will open in a new tab rather than a popup.
2. You can force a browser to use a new window (‘popup’) by specifying options in the 3rd parameter
3. If the window.open call was not part of a user-initiated event, it’ll open in a new window.
4. A “user initiated event” does not have to the same function call – but it must originate in the function invoked by a user click
5. If a user initiated event delegates or defers a function call (in an event listener or delegate not bound to the click event, or by using setTimeout for example), it loses it’s status as “user initiated”
6. Some popup blockers will allow windows opened from user initiated events, but not those opened otherwise.
7. If any popup is blocked, those normally allowed by a blocker (via user initiated events) will sometimes also be blocked.
Some examples…
Forcing a window to open in a new browser instance, instead of a new tab:
window.open('page.php', '', 'width=1000');
The following would qualify as a user-initiated event, even though it calls another function:
function o(){
window.open('page.php');
}
$('button').addEvent('click', o);
The following would not qualify as a user-initiated event, since the setTimeout defers it:
function g(){
setTimeout(o, 1);
}
function o(){
window.open('page.php');
}
$('button').addEvent('click', g);
Simple timeout in java
What you are looking for can be found here. It may exist a more elegant way to accomplish that, but one possible approach is
Option 1 (preferred):
final Duration timeout = Duration.ofSeconds(30);
ExecutorService executor = Executors.newSingleThreadExecutor();
final Future<String> handler = executor.submit(new Callable() {
@Override
public String call() throws Exception {
return requestDataFromModem();
}
});
try {
handler.get(timeout.toMillis(), TimeUnit.MILLISECONDS);
} catch (TimeoutException e) {
handler.cancel(true);
}
executor.shutdownNow();
Option 2:
final Duration timeout = Duration.ofSeconds(30);
ScheduledExecutorService executor = Executors.newScheduledThreadPool(1);
final Future<String> handler = executor.submit(new Callable() {
@Override
public String call() throws Exception {
return requestDataFromModem();
}
});
executor.schedule(new Runnable() {
@Override
public void run(){
handler.cancel(true);
}
}, timeout.toMillis(), TimeUnit.MILLISECONDS);
executor.shutdownNow();
Those are only a draft so that you can get the main idea.
How to use the toString method in Java?
It may optionally have uses within the context of an application but far more often it is used for debugging purposes. For example, when you hit a breakpoint in an IDE, it's far easier to read a meaningful toString()
of objects than it is to inspect their members.
There is no set requirement for what a toString()
method should do. By convention, most often it will tell you the name of the class and the value of pertinent data members. More often than not, toString()
methods are auto-generated in IDEs.
Relying on particular output from a toString()
method or parsing it within a program is a bad idea. Whatever you do, don't go down that route.
Difference between "git add -A" and "git add ."
Git Version 1.x
Command |
New Files |
Modified Files |
Deleted Files |
Description |
git add -A |
?? |
?? |
?? |
Stage all (new, modified, deleted) files |
git add . |
?? |
?? |
? |
Stage new and modified files only in current folder |
git add -u |
? |
?? |
?? |
Stage modified and deleted files only |
Git Version 2.x
Command |
New Files |
Modified Files |
Deleted Files |
Description |
git add -A |
?? |
?? |
?? |
Stage all (new, modified, deleted) files |
git add . |
?? |
?? |
?? |
Stage all (new, modified, deleted) files in current folder |
git add --ignore-removal . |
?? |
?? |
? |
Stage new and modified files only |
git add -u |
? |
?? |
?? |
Stage modified and deleted files only |
Long-form flags:
git add -A
is equivalent to git add --all
git add -u
is equivalent to git add --update
Further reading:
Get the element triggering an onclick event in jquery?
Try this
<input onclick="confirmSubmit(event);" type="button" value="Send" />
Along with this
function confirmSubmit(event){
var domElement =$(event.target);
console.log(domElement.attr('type'));
}
I tried it in firefox, it prints the 'type' attribute of dom Element clicked. I guess you can then get the form via the parents() methods using this object.
How to construct a set out of list items in python?
The most direct solution is this:
s = set(filelist)
The issue in your original code is that the values weren't being assigned to the set. Here's the fixed-up version of your code:
s = set()
for filename in filelist:
s.add(filename)
print(s)
Creating a DateTime in a specific Time Zone in c#
You'll have to create a custom object for that. Your custom object will contain two values:
Not sure if there already is a CLR-provided data type that has that, but at least the TimeZone component is already available.
insert a NOT NULL column to an existing table
Other SQL implementations have similar restrictions. The reason is that adding a column requires adding values for that column (logically, even if not physically), which default to NULL
. If you don't allow NULL
, and don't have a default
, what is the value going to be?
Since SQL Server supports ADD CONSTRAINT
, I'd recommend Pavel's approach of creating a nullable column, and then adding a NOT NULL
constraint after you've filled it with non-NULL
values.
Pip - Fatal error in launcher: Unable to create process using '"'
This worked for me under Windows 10 x64
:
Ensure that the Python directories are in the path, e.g.:
# Edit Environment variables so that variable "path" points to the new location.
# Insert these at the start of the list (or delete other Python directories), as Windows takes the first match it finds.
# Run the program "Edit the System Environment Variables".
# Or see Control Panel under "System Properties".
S:\Research\bin\Python375\Scripts\
S:\Research\bin\Python375\
Then:
python -m pip install --upgrade --force-reinstall pip
In my particular case, the error was caused by shifting the Python directory to a new location.
How do I get extra data from intent on Android?
If you are trying to get extra data in fragments then you can try using:
Place data using:
Bundle args = new Bundle();
args.putInt(DummySectionFragment.ARG_SECTION_NUMBER);
Get data using:
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
getArguments().getInt(ARG_SECTION_NUMBER);
getArguments().getString(ARG_SECTION_STRING);
getArguments().getBoolean(ARG_SECTION_BOOL);
getArguments().getChar(ARG_SECTION_CHAR);
getArguments().getByte(ARG_SECTION_DATA);
}
How to "fadeOut" & "remove" a div in jQuery?
you really should try to use jQuery in a separate file, not inline. Here is what you need:
<a class="notificationClose "><img src="close.png"/></a>
And then this at the bottom of your page in <script>
tags at the very least or in a external JavaScript file.
$(".notificationClose").click(function() {
$("#notification").fadeOut("normal", function() {
$(this).remove();
});
});
Python 2.7: %d, %s, and float()
Try the following:
print "First is: %f" % (first)
print "Second is: %f" % (second)
I am unsure what answer is. But apart from that, this will be:
print "DONE: %f DIVIDED BY %f EQUALS %f, SWEET MATH BRO!" % (first, second, ans)
There's a lot of text on Format String Specifiers. You can google it and get a list of specifiers. One thing I forgot to note:
If you try this:
print "First is: %s" % (first)
It converts the float value in first to a string. So that would work as well.
Upload Image using POST form data in Python-requests
From wechat api doc:
curl -F [email protected] "http://file.api.wechat.com/cgi-bin/media/upload?access_token=ACCESS_TOKEN&type=TYPE"
Translate the command above to python:
import requests
url = 'http://file.api.wechat.com/cgi-bin/media/upload?access_token=ACCESS_TOKEN&type=TYPE'
files = {'media': open('test.jpg', 'rb')}
requests.post(url, files=files)
Impact of Xcode build options "Enable bitcode" Yes/No
Bitcode makes crash reporting harder. Here is a quote from HockeyApp (which also true for any other crash reporting solutions):
When uploading an app to the App Store and leaving the "Bitcode" checkbox enabled, Apple will use that Bitcode build and re-compile it on their end before distributing it to devices. This will result in the binary getting a new UUID and there is an option to download a corresponding dSYM through Xcode.
Note: the answer was edited on Jan 2016 to reflect most recent changes
MySQL - DATE_ADD month interval
BETWEEN ... AND
If expr is greater than or equal to min and expr is less than or equal to max, BETWEEN
returns 1, otherwise it returns 0.
The important part here is EQUAL to max., which 1st of July is.
How to Clear Console in Java?
If your terminal supports ANSI escape codes, this clears the screen and moves the cursor to the first row, first column:
System.out.print("\033[H\033[2J");
System.out.flush();
This works on almost all UNIX terminals and terminal emulators. The Windows cmd.exe
does not interprete ANSI escape codes.
Detect Safari browser
I use this
function getBrowserName() {
var name = "Unknown";
if(navigator.userAgent.indexOf("MSIE")!=-1){
name = "MSIE";
}
else if(navigator.userAgent.indexOf("Firefox")!=-1){
name = "Firefox";
}
else if(navigator.userAgent.indexOf("Opera")!=-1){
name = "Opera";
}
else if(navigator.userAgent.indexOf("Chrome") != -1){
name = "Chrome";
}
else if(navigator.userAgent.indexOf("Safari")!=-1){
name = "Safari";
}
return name;
}
if( getBrowserName() == "Safari" ){
alert("You are using Safari");
}else{
alert("You are surfing on " + getBrowserName(name));
}
List all of the possible goals in Maven 2?
Lets make it very simple:
Maven Lifecycles:
1. Clean
2. Default (build)
3. Site
Maven Phases of the Default Lifecycle:
1. Validate
2. Compile
3. Test
4. Package
5. Verify
6. Install
7. Deploy
Note:
Don't mix or get confused with maven goals with maven lifecycle.
See Maven Build Lifecycle Basics1
Rails :include vs. :joins
tl;dr
I contrast them in two ways:
joins - For conditional selection of records.
includes - When using an association on each member of a result set.
Longer version
Joins is meant to filter the result set coming from the database. You use it to do set operations on your table. Think of this as a where clause that performs set theory.
Post.joins(:comments)
is the same as
Post.where('id in (select post_id from comments)')
Except that if there are more than one comment you will get duplicate posts back with the joins. But every post will be a post that has comments. You can correct this with distinct:
Post.joins(:comments).count
=> 10
Post.joins(:comments).distinct.count
=> 2
In contract, the includes
method will simply make sure that there are no additional database queries when referencing the relation (so that we don't make n + 1 queries)
Post.includes(:comments).count
=> 4 # includes posts without comments so the count might be higher.
The moral is, use joins
when you want to do conditional set operations and use includes
when you are going to be using a relation on each member of a collection.
WMI "installed" query different from add/remove programs list?
Installed products consist of installed software elements and features so it's worth checking wmic alias's for PRODUCT as well as checking SOFTWAREELEMENT and SOFTWAREFEATURE:
wmic product get name,version
wmic softwareelement get name,version
wmic softwarefeature get name,version
jQuery UI Dialog OnBeforeUnload
For ASP.NET MVC if you want to make an exception for leaving the page via submitting a particular form:
Set a form id:
@using (Html.BeginForm("Create", "MgtJob", FormMethod.Post, new { id = "createjob" }))
{
// Your code
}
<script type="text/javascript">
// Without submit form
$(window).bind('beforeunload', function () {
if ($('input').val() !== '') {
return "It looks like you have input you haven't submitted."
}
});
// this will call before submit; and it will unbind beforeunload
$(function () {
$("#createjob").submit(function (event) {
$(window).unbind("beforeunload");
});
});
</script>
Maximum length of HTTP GET request
Browser limits are:
Browser Address bar document.location
or anchor tag
---------------------------------------------------
Chrome 32779 >64k
Android 8192 >64k
Firefox >64k >64k
Safari >64k >64k
Internet Explorer 11 2047 5120
Edge 16 2047 10240
Want more? See this question on Stack Overflow.
Apply pandas function to column to create multiple new columns?
Summary: If you only want to create a few columns, use df[['new_col1','new_col2']] = df[['data1','data2']].apply( function_of_your_choosing(x), axis=1)
For this solution, the number of new columns you are creating must be equal to the number columns you use as input to the .apply() function. If you want to do something else, have a look at the other answers.
Details
Let's say you have two-column dataframe. The first column is a person's height when they are 10; the second is said person's height when they are 20.
Suppose you need to calculate both the mean of each person's heights and sum of each person's heights. That's two values per each row.
You could do this via the following, soon-to-be-applied function:
def mean_and_sum(x):
"""
Calculates the mean and sum of two heights.
Parameters:
:x -- the values in the row this function is applied to. Could also work on a list or a tuple.
"""
sum=x[0]+x[1]
mean=sum/2
return [mean,sum]
You might use this function like so:
df[['height_at_age_10','height_at_age_20']].apply(mean_and_sum(x),axis=1)
(To be clear: this apply function takes in the values from each row in the subsetted dataframe and returns a list.)
However, if you do this:
df['Mean_&_Sum'] = df[['height_at_age_10','height_at_age_20']].apply(mean_and_sum(x),axis=1)
you'll create 1 new column that contains the [mean,sum] lists, which you'd presumably want to avoid, because that would require another Lambda/Apply.
Instead, you want to break out each value into its own column. To do this, you can create two columns at once:
df[['Mean','Sum']] = df[['height_at_age_10','height_at_age_20']]
.apply(mean_and_sum(x),axis=1)
Are the shift operators (<<, >>) arithmetic or logical in C?
Here are functions to guarantee logical right shift and arithmetic right shift of an int in C:
int logicalRightShift(int x, int n) {
return (unsigned)x >> n;
}
int arithmeticRightShift(int x, int n) {
if (x < 0 && n > 0)
return x >> n | ~(~0U >> n);
else
return x >> n;
}
How to properly highlight selected item on RecyclerView?
Decision with Interfaces and Callbacks.
Create Interface with select and unselect states:
public interface ItemTouchHelperViewHolder {
/**
* Called when the {@link ItemTouchHelper} first registers an item as being moved or swiped.
* Implementations should update the item view to indicate it's active state.
*/
void onItemSelected();
/**
* Called when the {@link ItemTouchHelper} has completed the move or swipe, and the active item
* state should be cleared.
*/
void onItemClear();
}
Implement interface in ViewHolder:
public static class ItemViewHolder extends RecyclerView.ViewHolder implements
ItemTouchHelperViewHolder {
public LinearLayout container;
public PositionCardView content;
public ItemViewHolder(View itemView) {
super(itemView);
container = (LinearLayout) itemView;
content = (PositionCardView) itemView.findViewById(R.id.content);
}
@Override
public void onItemSelected() {
/**
* Here change of item
*/
container.setBackgroundColor(Color.LTGRAY);
}
@Override
public void onItemClear() {
/**
* Here change of item
*/
container.setBackgroundColor(Color.WHITE);
}
}
Run state change on Callback:
public class ItemTouchHelperCallback extends ItemTouchHelper.Callback {
private final ItemTouchHelperAdapter mAdapter;
public ItemTouchHelperCallback(ItemTouchHelperAdapter adapter) {
this.mAdapter = adapter;
}
@Override
public boolean isLongPressDragEnabled() {
return true;
}
@Override
public boolean isItemViewSwipeEnabled() {
return true;
}
@Override
public int getMovementFlags(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder) {
int dragFlags = ItemTouchHelper.UP | ItemTouchHelper.DOWN;
int swipeFlags = ItemTouchHelper.END;
return makeMovementFlags(dragFlags, swipeFlags);
}
@Override
public boolean onMove(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, RecyclerView.ViewHolder target) {
...
}
@Override
public void onSwiped(final RecyclerView.ViewHolder viewHolder, int direction) {
...
}
@Override
public void onSelectedChanged(RecyclerView.ViewHolder viewHolder, int actionState) {
if (actionState != ItemTouchHelper.ACTION_STATE_IDLE) {
if (viewHolder instanceof ItemTouchHelperViewHolder) {
ItemTouchHelperViewHolder itemViewHolder =
(ItemTouchHelperViewHolder) viewHolder;
itemViewHolder.onItemSelected();
}
}
super.onSelectedChanged(viewHolder, actionState);
}
@Override
public void clearView(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder) {
super.clearView(recyclerView, viewHolder);
if (viewHolder instanceof ItemTouchHelperViewHolder) {
ItemTouchHelperViewHolder itemViewHolder =
(ItemTouchHelperViewHolder) viewHolder;
itemViewHolder.onItemClear();
}
}
}
Create RecyclerView with Callback (example):
mAdapter = new BuyItemsRecyclerListAdapter(MainActivity.this, positionsList, new ArrayList<BuyItem>());
positionsList.setAdapter(mAdapter);
positionsList.setLayoutManager(new LinearLayoutManager(this));
ItemTouchHelper.Callback callback = new ItemTouchHelperCallback(mAdapter);
mItemTouchHelper = new ItemTouchHelper(callback);
mItemTouchHelper.attachToRecyclerView(positionsList);
See more in article of iPaulPro: https://medium.com/@ipaulpro/drag-and-swipe-with-recyclerview-6a6f0c422efd#.6gh29uaaz
The tilde operator in Python
Besides being a bitwise complement operator, ~
can also help revert a boolean value, though it is not the conventional bool
type here, rather you should use numpy.bool_
.
This is explained in,
import numpy as np
assert ~np.True_ == np.False_
Reversing logical value can be useful sometimes, e.g., below ~
operator is used to cleanse your dataset and return you a column without NaN.
from numpy import NaN
import pandas as pd
matrix = pd.DataFrame([1,2,3,4,NaN], columns=['Number'], dtype='float64')
# Remove NaN in column 'Number'
matrix['Number'][~matrix['Number'].isnull()]
How do I install opencv using pip?
run the following command by creating a virtual enviroment using python 3 and run
pip3 install opencv-python
to check it has installed correctly run
python3 -c "import cv2"
max value of integer
Actually the size in bits of the int
, short
, long
depends on the compiler implementation.
E.g. on my Ubuntu 64 bit I have short
in 32
bits, when on another one 32bit Ubuntu version it is 16
bit.