Programs & Examples On #Specifier

Xcode couldn't find any provisioning profiles matching

Try to check Signing settings in Build settings for your project and target. Be sure that code signing identity section has correct identities for Debug and Release.

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Get git branch name in Jenkins Pipeline/Jenkinsfile

For pipeline:

pipeline {
  environment {
     BRANCH_NAME = "${GIT_BRANCH.split("/")[1]}"
  }
}

How to printf a 64-bit integer as hex?

The warning from your compiler is telling you that your format specifier doesn't match the data type you're passing to it.

Try using %lx or %llx. For more portability, include inttypes.h and use the PRIx64 macro.

For example: printf("val = 0x%" PRIx64 "\n", val); (note that it's string concatenation)

Jenkins - how to build a specific branch

To checkout the branch via Jenkins scripts use:

stage('Checkout SCM') {
    git branch: 'branchName', credentialsId: 'your_credentials', url: "giturlrepo"
}

How can I avoid getting this MySQL error Incorrect column specifier for column COLUMN NAME?

The auto_increment property only works for numeric columns (integer and floating point), not char columns:

CREATE TABLE discussion_topics (
    topic_id INT NOT NULL AUTO_INCREMENT,
    project_id char(36) NOT NULL,
    topic_subject VARCHAR(255) NOT NULL,
    topic_content TEXT default NULL,
    date_created DATETIME NOT NULL,
    date_last_post DATETIME NOT NULL,
    created_by_user_id char(36) NOT NULL,
    last_post_user_id char(36) NOT NULL,
    posts_count char(36) default NULL,
    PRIMARY KEY (topic_id)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 AUTO_INCREMENT=1;

Precision String Format Specifier In Swift

You can't do it (yet) with string interpolation. Your best bet is still going to be NSString formatting:

println(NSString(format:"%.2f", sqrt(2.0)))

Extrapolating from python, it seems like a reasonable syntax might be:

@infix func % (value:Double, format:String) -> String {
    return NSString(format:format, value)
}

Which then allows you to use them as:

M_PI % "%5.3f"                // "3.142"

You can define similar operators for all of the numeric types, unfortunately I haven't found a way to do it with generics.

Swift 5 Update

As of at least Swift 5, String directly supports the format: initializer, so there's no need to use NSString and the @infix attribute is no longer needed which means the samples above should be written as:

println(String(format:"%.2f", sqrt(2.0)))

func %(value:Double, format:String) -> String {
    return String(format:format, value)
}

Double.pi % "%5.3f"         // "3.142"

This declaration has no storage class or type specifier in C++

Calling m.check(side), meaning you are running actual code, but you can't run code outside main() - you can only define variables. In C++, code can only appear inside function bodies or in variable initializes.

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

This solved the problem for me (Ubuntu 16.04):

sudo apt-get install build-essential libssl-dev libffi-dev python-dev python3-dev

and then it was working like this:

pip install cryptography
pip install pyopenssl ndg-httpsclient pyasn1

getting the error: expected identifier or ‘(’ before ‘{’ token

{
int main(void);

should be

int main(void)
{

Then I let you fix the next compilation errors of your program...

Format specifier %02x

Your string is wider than your format width of 2. So there's no padding to be done.

printf, wprintf, %s, %S, %ls, char* and wchar*: Errors not announced by a compiler warning?

At least in Visual C++: printf (and other ACSII functions): %s represents an ASCII string %S is a Unicode string wprintf (and other Unicode functions): %s is a Unicode string %S is an ASCII string

As far as no compiler warnings, printf uses a variable argument list, with only the first argument able to be type checked. The compiler is not designed to parse the format string and type check the parameters that match. In cases of functions like printf, that is up to the programmer

What is the printf format specifier for bool?

There is no format specifier for bool. You can print it using some of the existing specifiers for printing integral types or do something more fancy:

 printf("%s", x?"true":"false");

How abstraction and encapsulation differ?

Encapsulation: Hiding implementation details (NOTE: data AND/OR methods) such that only what is sensibly readable/writable/usable by externals is accessible to them, everything else is "untouchable" directly.

Abstraction: This sometimes refers specifically to a type that cannot be instantiated and which provides a template for other types that can be, usually via subclassing. More generally "abstraction" refers to making/having something that is less detailed, less specific, less granular.

There is some similarity, overlap between the concepts but the best way to remember it is like this: Encapsulation is more about hiding the details, whereas abstraction is more about generalizing the details.

Printf width specifier to maintain precision of floating-point value

No, there is no such printf width specifier to print floating-point with maximum precision. Let me explain why.

The maximum precision of float and double is variable, and dependent on the actual value of the float or double.

Recall float and double are stored in sign.exponent.mantissa format. This means that there are many more bits used for the fractional component for small numbers than for big numbers.

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For example, float can easily distinguish between 0.0 and 0.1.

float r = 0;
printf( "%.6f\n", r ) ; // 0.000000
r+=0.1 ;
printf( "%.6f\n", r ) ; // 0.100000

But float has no idea of the difference between 1e27 and 1e27 + 0.1.

r = 1e27;
printf( "%.6f\n", r ) ; // 999999988484154753734934528.000000
r+=0.1 ;
printf( "%.6f\n", r ) ; // still 999999988484154753734934528.000000

This is because all the precision (which is limited by the number of mantissa bits) is used up for the large part of the number, left of the decimal.

The %.f modifier just says how many decimal values you want to print from the float number as far as formatting goes. The fact that the accuracy available depends on the size of the number is up to you as the programmer to handle. printf can't/doesn't handle that for you.

How to state in requirements.txt a direct github source

Normally your requirements.txt file would look something like this:

package-one==1.9.4
package-two==3.7.1
package-three==1.0.1
...

To specify a Github repo, you do not need the package-name== convention.

The examples below update package-two using a GitHub repo. The text between @ and # denotes the specifics of the package.

Specify commit hash (41b95ec in the context of updated requirements.txt):

package-one==1.9.4
git+git://github.com/path/to/package-two@41b95ec#egg=package-two
package-three==1.0.1

Specify branch name (master):

git+git://github.com/path/to/package-two@master#egg=package-two

Specify tag (0.1):

git+git://github.com/path/to/[email protected]#egg=package-two

Specify release (3.7.1):

git+git://github.com/path/to/package-two@releases/tag/v3.7.1#egg=package-two

Note that #egg=package-two is not a comment here, it is to explicitly state the package name

This blog post has some more discussion on the topic.

What does git rev-parse do?

git rev-parse is an ancillary plumbing command primarily used for manipulation.

One common usage of git rev-parse is to print the SHA1 hashes given a revision specifier. In addition, it has various options to format this output such as --short for printing a shorter unique SHA1.

There are other use cases as well (in scripts and other tools built on top of git) that I've used for:

  • --verify to verify that the specified object is a valid git object.
  • --git-dir for displaying the abs/relative path of the the .git directory.
  • Checking if you're currently within a repository using --is-inside-git-dir or within a work-tree using --is-inside-work-tree
  • Checking if the repo is a bare using --is-bare-repository
  • Printing SHA1 hashes of branches (--branches), tags (--tags) and the refs can also be filtered based on the remote (using --remote)
  • --parse-opt to normalize arguments in a script (kind of similar to getopt) and print an output string that can be used with eval

Massage just implies that it is possible to convert the info from one form into another i.e. a transformation command. These are some quick examples I can think of:

  • a branch or tag name into the commit's SHA1 it is pointing to so that it can be passed to a plumbing command which only accepts SHA1 values for the commit.
  • a revision range A..B for git log or git diff into the equivalent arguments for the underlying plumbing command as B ^A

Passing structs to functions

It is possible to construct a struct inside the function arguments:

function({ .variable = PUT_DATA_HERE });

C - The %x format specifier

The format string attack on printf you mentioned isn't specific to the "%x" formatting - in any case where printf has more formatting parameters than passed variables, it will read values from the stack that do not belong to it. You will get the same issue with %d for example. %x is useful when you want to see those values as hex.

As explained in previous answers, %08x will produce a 8 digits hex number, padded by preceding zeros.

Using the formatting in your code example in printf, with no additional parameters:

printf ("%08x %08x %08x %08x");

Will fetch 4 parameters from the stack and display them as 8-digits padded hex numbers.

Correct format specifier to print pointer or address?

p is the conversion specifier to print pointers. Use this.

int a = 42;

printf("%p\n", (void *) &a);

Remember that omitting the cast is undefined behavior and that printing with p conversion specifier is done in an implementation-defined manner.

How to install OpenSSL for Python

SSL development libraries have to be installed

CentOS:

$ yum install openssl-devel libffi-devel

Ubuntu:

$ apt-get install libssl-dev libffi-dev

OS X (with Homebrew installed):

$ brew install openssl

Error: expected type-specifier before 'ClassName'

For future people struggling with a similar problem, the situation is that the compiler simply cannot find the type you are using (even if your Intelisense can find it).

This can be caused in many ways:

  • You forgot to #include the header that defines it.
  • Your inclusion guards (#ifndef BLAH_H) are defective (your #ifndef BLAH_H doesn't match your #define BALH_H due to a typo or copy+paste mistake).
  • Your inclusion guards are accidentally used twice (two separate files both using #define MYHEADER_H, even if they are in separate directories)
  • You forgot that you are using a template (eg. new Vector() should be new Vector<int>())
  • The compiler is thinking you meant one scope when really you meant another (For example, if you have NamespaceA::NamespaceB, AND a <global scope>::NamespaceB, if you are already within NamespaceA, it'll look in NamespaceA::NamespaceB and not bother checking <global scope>::NamespaceB) unless you explicitly access it.
  • You have a name clash (two entities with the same name, such as a class and an enum member).

To explicitly access something in the global namespace, prefix it with ::, as if the global namespace is a namespace with no name (e.g. ::MyType or ::MyNamespace::MyType).

What is the format specifier for unsigned short int?

From the Linux manual page:

h      A  following  integer conversion corresponds to a short int or unsigned short int argument, or a fol-
       lowing n conversion corresponds to a pointer to a short int argument.

So to print an unsigned short integer, the format string should be "%hu".

Assign a variable inside a Block to a variable outside a Block

Try __weak if you get any warning regarding retain cycle else use __block

Person *strongPerson = [Person new];
__weak Person *weakPerson = person;

Now you can refer weakPerson object inside block.

C++ auto keyword. Why is it magic?

For variables, specifies that the type of the variable that is being declared will be automatically deduced from its initializer. For functions, specifies that the return type is a trailing return type or will be deduced from its return statements (since C++14).

Syntax

auto variable initializer   (1) (since C++11)

auto function -> return type    (2) (since C++11)

auto function   (3) (since C++14)

decltype(auto) variable initializer (4) (since C++14)

decltype(auto) function (5) (since C++14)

auto :: (6) (concepts TS)

cv(optional) auto ref(optional) parameter   (7) (since C++14)

Explanation

1) When declaring variables in block scope, in namespace scope, in initialization statements of for loops, etc., the keyword auto may be used as the type specifier. Once the type of the initializer has been determined, the compiler determines the type that will replace the keyword auto using the rules for template argument deduction from a function call (see template argument deduction#Other contexts for details). The keyword auto may be accompanied by modifiers, such as const or &, which will participate in the type deduction. For example, given const auto& i = expr;, the type of i is exactly the type of the argument u in an imaginary template template<class U> void f(const U& u) if the function call f(expr) was compiled. Therefore, auto&& may be deduced either as an lvalue reference or rvalue reference according to the initializer, which is used in range-based for loop. If auto is used to declare multiple variables, the deduced types must match. For example, the declaration auto i = 0, d = 0.0; is ill-formed, while the declaration auto i = 0, *p = &i; is well-formed and the auto is deduced as int.

2) In a function declaration that uses the trailing return type syntax, the keyword auto does not perform automatic type detection. It only serves as a part of the syntax.

3) In a function declaration that does not use the trailing return type syntax, the keyword auto indicates that the return type will be deduced from the operand of its return statement using the rules for template argument deduction.

4) If the declared type of the variable is decltype(auto), the keyword auto is replaced with the expression (or expression list) of its initializer, and the actual type is deduced using the rules for decltype.

5) If the return type of the function is declared decltype(auto), the keyword auto is replaced with the operand of its return statement, and the actual return type is deduced using the rules for decltype.

6) A nested-name-specifier of the form auto:: is a placeholder that is replaced by a class or enumeration type following the rules for constrained type placeholder deduction.

7) A parameter declaration in a lambda expression. (since C++14) A function parameter declaration. (concepts TS)

Notes Until C++11, auto had the semantic of a storage duration specifier. Mixing auto variables and functions in one declaration, as in auto f() -> int, i = 0; is not allowed.

For more info : http://en.cppreference.com/w/cpp/language/auto

NSAttributedString add text alignment

I was searching for the same issue and was able to center align the text in a NSAttributedString this way:

NSMutableParagraphStyle *paragraphStyle = [[NSMutableParagraphStyle alloc]init] ;
[paragraphStyle setAlignment:NSTextAlignmentCenter];

NSMutableAttributedString *attribString = [[NSMutableAttributedString alloc]initWithString:string];
[attribString addAttribute:NSParagraphStyleAttributeName value:paragraphStyle range:NSMakeRange(0, [string length])];

How to access private data members outside the class without making "friend"s?

access private members outside class ....only for study purpose .... This program accepts all the below conditions "I dont want to create member function for above class A. And also i dont want to inherit the above class A. I dont want to change the specifier of iData."

//here member function is used only to input and output the private values ... //void hack() is defined outside the class...

//GEEK MODE....;)
#include<iostream.h>
#include<conio.h>

    class A
    {
    private :int iData,x;
    public: void get()             //enter the values
        {cout<<"Enter iData : ";
            cin>>iData;cout<<"Enter x : ";cin>>x;}

        void put()                               //displaying values
    {cout<<endl<<"sum = "<<iData+x;}
};

void hack();        //hacking function

void main()
{A obj;clrscr();
obj.get();obj.put();hack();obj.put();getch();
}

void hack()         //hack begins
{int hck,*ptr=&hck;
cout<<endl<<"Enter value of private data (iData or x) : ";
cin>>hck;     //enter the value assigned for iData or x
for(int i=0;i<5;i++)
{ptr++;
if(*ptr==hck)
{cout<<"Private data hacked...!!!\nChange the value : ";
cin>>*ptr;cout<<hck<<" Is chaged to : "<<*ptr;
return;}
}cout<<"Sorry value not found.....";
}

What are access specifiers? Should I inherit with private, protected or public?

The explanation from Scott Meyers in Effective C++ might help understand when to use them:

Public inheritance should model "is-a relationship," whereas private inheritance should be used for "is-implemented-in-terms-of" - so you don't have to adhere to the interface of the superclass, you're just reusing the implementation.

'printf' with leading zeros in C

Your format specifier is incorrect. From the printf() man page on my machine:

0 A zero '0' character indicating that zero-padding should be used rather than blank-padding. A '-' overrides a '0' if both are used;

Field Width: An optional digit string specifying a field width; if the output string has fewer characters than the field width it will be blank-padded on the left (or right, if the left-adjustment indicator has been given) to make up the field width (note that a leading zero is a flag, but an embedded zero is part of a field width);

Precision: An optional period, '.', followed by an optional digit string giving a precision which specifies the number of digits to appear after the decimal point, for e and f formats, or the maximum number of characters to be printed from a string; if the digit string is missing, the precision is treated as zero;

For your case, your format would be %09.3f:

#include <stdio.h>

int main(int argc, char **argv)
{
  printf("%09.3f\n", 4917.24);
  return 0;
}

Output:

$ make testapp
cc     testapp.c   -o testapp
$ ./testapp 
04917.240

Note that this answer is conditional on your embedded system having a printf() implementation that is standard-compliant for these details - many embedded environments do not have such an implementation.

Float to String format specifier

Firstly, as Etienne says, float in C# is Single. It is just the C# keyword for that data type.

So you can definitely do this:

float f = 13.5f;
string s = f.ToString("R");

Secondly, you have referred a couple of times to the number's "format"; numbers don't have formats, they only have values. Strings have formats. Which makes me wonder: what is this thing you have that has a format but is not a string? The closest thing I can think of would be decimal, which does maintain its own precision; however, calling simply decimal.ToString should have the effect you want in that case.

How about including some example code so we can see exactly what you're doing, and why it isn't achieving what you want?

Difference between text and varchar (character varying)

character varying(n), varchar(n) - (Both the same). value will be truncated to n characters without raising an error.

character(n), char(n) - (Both the same). fixed-length and will pad with blanks till the end of the length.

text - Unlimited length.

Example:

Table test:
   a character(7)
   b varchar(7)

insert "ok    " to a
insert "ok    " to b

We get the results:

a        | (a)char_length | b     | (b)char_length
----------+----------------+-------+----------------
"ok     "| 7              | "ok"  | 2

C++ - struct vs. class

Ok, POD means plain old data. That usually refers to structs without any methods because these types are then used to structure multiple data that belong together.

As for structs not having methods: I have seen more than once that a struct had methods, and I don't feel that this would be unnatural.

Correct format specifier for double in printf

Format %lf is a perfectly correct printf format for double, exactly as you used it. There's nothing wrong with your code.

Format %lf in printf was not supported in old (pre-C99) versions of C language, which created superficial "inconsistency" between format specifiers for double in printf and scanf. That superficial inconsistency has been fixed in C99.

You are not required to use %lf with double in printf. You can use %f as well, if you so prefer (%lf and %f are equivalent in printf). But in modern C it makes perfect sense to prefer to use %f with float, %lf with double and %Lf with long double, consistently in both printf and scanf.

printf and long double

Was having this issue testing long doubles, and alas, I came across a fix! You have to compile your project with -D__USE_MINGW_ANSI_STDIO:

Jason Huntley@centurian /home/developer/dependencies/Python-2.7.3/test $ gcc main.c

Jason Huntley@centurian /home/developer/dependencies/Python-2.7.3/test $ a.exe c=0.000000

Jason Huntley@centurian /home/developer/dependencies/Python-2.7.3/test $ gcc main.c -D__USE_MINGW_ANSI_STDIO

Jason Huntley@centurian /home/developer/dependencies/Python-2.7.3/test $ a.exe c=42.000000

Code:

Jason Huntley@centurian /home/developer/dependencies/Python-2.7.3/test
$ cat main.c
#include <stdio.h>

int main(int argc, char **argv)
{
   long double c=42;

   c/3;

   printf("c=%Lf\n",c);

   return 0;
}

How to use java.String.format in Scala?

You don't need to use numbers to indicate positioning. By default, the position of the argument is simply the order in which it appears in the string.

Here's an example of the proper way to use this:

String result = String.format("The format method is %s!", "great");
// result now equals  "The format method is great!".

You will always use a % followed by some other characters to let the method know how it should display the string. %s is probably the most common, and it just means that the argument should be treated as a string.

I won't list every option, but I'll give a few examples just to give you an idea:

// we can specify the # of decimals we want to show for a floating point:
String result = String.format("10 / 3 = %.2f", 10.0 / 3.0);
// result now equals  "10 / 3 = 3.33"

// we can add commas to long numbers:
result = String.format("Today we processed %,d transactions.", 1000000);
// result now equals  "Today we processed 1,000,000 transactions."

String.format just uses a java.util.Formatter, so for a full description of the options you can see the Formatter javadocs.

And, as BalusC mentions, you will see in the documentation that is possible to change the default argument ordering if you need to. However, probably the only time you'd need / want to do this is if you are using the same argument more than once.

What is the default access specifier in Java?

First of all let me say one thing there is no such term as "Access specifier" in java. We should call everything as "Modifiers". As we know that final, static, synchronised, volatile.... are called as modifiers, even Public, private, protected, default, abstract should also be called as modifiers . Default is such a modifiers where physical existence is not there but no modifiers is placed then it should be treated as default modifiers.

To justify this take one example:

public class Simple{  
    public static void main(String args[]){  
     System.out.println("Hello Java");  
    }  
}  

Output will be: Hello Java

Now change public to private and see what compiler error you get: It says "Modifier private is not allowed here" What conclusion is someone can be wrong or some tutorial can be wrong but compiler cannot be wrong. So we can say there is no term access specifier in java everything is modifiers.

What is the use of the %n format specifier in C?

Nothing printed. The argument must be a pointer to a signed int, where the number of characters written so far is stored.

#include <stdio.h>

int main()
{
  int val;

  printf("blah %n blah\n", &val);

  printf("val = %d\n", val);

  return 0;

}

The previous code prints:

blah  blah
val = 5

printf format specifiers for uint32_t and size_t

Sounds like you're expecting size_t to be the same as unsigned long (possibly 64 bits) when it's actually an unsigned int (32 bits). Try using %zu in both cases.

I'm not entirely certain though.

jquery data selector

$('a[data-category="music"]')

It works. See Attribute Equals Selector [name=”value”].

How can one print a size_t variable portably using the printf family?

Will it warn you if you pass a 32-bit unsigned integer to a %lu format? It should be fine since the conversion is well-defined and doesn't lose any information.

I've heard that some platforms define macros in <inttypes.h> that you can insert into the format string literal but I don't see that header on my Windows C++ compiler, which implies it may not be cross-platform.

How can I account for period (AM/PM) using strftime?

>>> from datetime import datetime
>>> print(datetime.today().strftime("%H:%M %p"))
15:31 AM

Try replacing %I with %H.

C++ Redefinition Header Files (winsock2.h)

By using "header guards":

#ifndef MYCLASS_H
#define MYCLASS_H

// This is unnecessary, see comments.
//#pragma once

// MyClass.h

#include <winsock2.h>

class MyClass
{

// methods
public:
    MyClass(unsigned short port);
    virtual ~MyClass(void);
};

#endif

Where can I find documentation on formatting a date in JavaScript?

Where is the documentation which lists the format specifiers supported by the Date() object?

I stumbled across this today and was quite surprised that no one took the time to answer this simple question. True, there are many libraries out there to help with date manipulation. Some are better than others. But that wasn't the question asked.

AFAIK, pure JavaScript doesn't support format specifiers the way you have indicated you'd like to use them. But it does support methods for formatting dates and/or times, such as .toLocaleDateString(), .toLocaleTimeString(), and .toUTCString().

The Date object reference I use most frequently is on the w3schools.com website (but a quick Google search will reveal many more that may better meet your needs).

Also note that the Date Object Properties section provides a link to prototype, which illustrates some ways you can extend the Date object with custom methods. There has been some debate in the JavaScript community over the years about whether or not this is best practice, and I am not advocating for or against it, just pointing out its existence.

Where's the DateTime 'Z' format specifier?

Label1.Text = dt.ToString("dd MMM yyyy | hh:mm | ff | zzz | zz | z");

will output:

07 Mai 2009 | 08:16 | 13 | +02:00 | +02 | +2

I'm in Denmark, my Offset from GMT is +2 hours, witch is correct.

if you need to get the CLIENT Offset, I recommend that you check a little trick that I did. The Page is in a Server in UK where GMT is +00:00 and, as you can see you will get your local GMT Offset.


Regarding you comment, I did:

DateTime dt1 = DateTime.Now;
DateTime dt2 = dt1.ToUniversalTime();

Label1.Text = dt1.ToString("dd MMM yyyy | hh:mm | ff | zzz | zz | z");
Label2.Text = dt2.ToString("dd MMM yyyy | hh:mm | FF | ZZZ | ZZ | Z");

and I get this:

07 Mai 2009 | 08:24 | 14 | +02:00 | +02 | +2
07 Mai 2009 | 06:24 | 14 | ZZZ | ZZ | Z 

I get no Exception, just ... it does nothing with capital Z :(

I'm sorry, but am I missing something?


Reading carefully the MSDN on Custom Date and Time Format Strings

there is no support for uppercase 'Z'.

List of special characters for SQL LIKE clause

You should add that you have to add an extra ' to escape an exising ' in SQL Server:

smith's -> smith''s

.NET Format a string with fixed spaces

This will give you exactly the strings that you asked for:

string s = "String goes here";
string lineAlignedRight  = String.Format("{0,27}", s);
string lineAlignedCenter = String.Format("{0,-27}",
    String.Format("{0," + ((27 + s.Length) / 2).ToString() +  "}", s));
string lineAlignedLeft   = String.Format("{0,-27}", s);

What does this error mean: "error: expected specifier-qualifier-list before 'type_name'"?

this error basically comes when you use the object before using it.

What good are SQL Server schemas?

I know it's an old thread, but I just looked into schemas myself and think the following could be another good candidate for schema usage:

In a Datawarehouse, with data coming from different sources, you can use a different schema for each source, and then e.g. control access based on the schemas. Also avoids the possible naming collisions between the various source, as another poster replied above.

Avoid trailing zeroes in printf()

Why not just do this?

double f = 359.01335;
printf("%g", round(f * 1000.0) / 1000.0);

How to save a BufferedImage as a File

File outputfile = new File("image.jpg");
ImageIO.write(bufferedImage, "jpg", outputfile);

How do I filter date range in DataTables?

Here is my solution, there is no way to use momemt.js.Here is DataTable with Two DatePickers for DateRange (To and From) Filter.

$.fn.dataTable.ext.search.push(
  function (settings, data, dataIndex) {
    var min = $('#min').datepicker("getDate");
    var max = $('#max').datepicker("getDate");
    var startDate = new Date(data[4]);
    if (min == null && max == null) { return true; }
    if (min == null && startDate <= max) { return true; }
    if (max == null && startDate >= min) { return true; }
    if (startDate <= max && startDate >= min) { return true; }
    return false;
  }
);
  

    

Remove substring from the string

If you only have one occurrence of the target string you can use:

str[target] = ''

or

str.sub(target, '')

If you have multiple occurrences of target use:

str.gsub(target, '')

For instance:

asdf = 'foo bar'
asdf['bar'] = ''
asdf #=> "foo "

asdf = 'foo bar'
asdf.sub('bar', '') #=> "foo "
asdf = asdf + asdf #=> "foo barfoo bar"
asdf.gsub('bar', '') #=> "foo foo "

If you need to do in-place substitutions use the "!" versions of gsub! and sub!.

IntelliJ does not show project folders

For me in IntelliJ it was showing me a popup to import the existing project as gradle project. I just clicked ok on it and then the folder structure appeared properly.

Volatile vs. Interlocked vs. lock

Worst (won't actually work)

Change the access modifier of counter to public volatile

As other people have mentioned, this on its own isn't actually safe at all. The point of volatile is that multiple threads running on multiple CPUs can and will cache data and re-order instructions.

If it is not volatile, and CPU A increments a value, then CPU B may not actually see that incremented value until some time later, which may cause problems.

If it is volatile, this just ensures the two CPUs see the same data at the same time. It doesn't stop them at all from interleaving their reads and write operations which is the problem you are trying to avoid.

Second Best:

lock(this.locker) this.counter++;

This is safe to do (provided you remember to lock everywhere else that you access this.counter). It prevents any other threads from executing any other code which is guarded by locker. Using locks also, prevents the multi-CPU reordering problems as above, which is great.

The problem is, locking is slow, and if you re-use the locker in some other place which is not really related then you can end up blocking your other threads for no reason.

Best

Interlocked.Increment(ref this.counter);

This is safe, as it effectively does the read, increment, and write in 'one hit' which can't be interrupted. Because of this, it won't affect any other code, and you don't need to remember to lock elsewhere either. It's also very fast (as MSDN says, on modern CPUs, this is often literally a single CPU instruction).

I'm not entirely sure however if it gets around other CPUs reordering things, or if you also need to combine volatile with the increment.

InterlockedNotes:

  1. INTERLOCKED METHODS ARE CONCURRENTLY SAFE ON ANY NUMBER OF COREs OR CPUs.
  2. Interlocked methods apply a full fence around instructions they execute, so reordering does not happen.
  3. Interlocked methods do not need or even do not support access to a volatile field, as volatile is placed a half fence around operations on given field and interlocked is using the full fence.

Footnote: What volatile is actually good for.

As volatile doesn't prevent these kinds of multithreading issues, what's it for? A good example is saying you have two threads, one which always writes to a variable (say queueLength), and one which always reads from that same variable.

If queueLength is not volatile, thread A may write five times, but thread B may see those writes as being delayed (or even potentially in the wrong order).

A solution would be to lock, but you could also use volatile in this situation. This would ensure that thread B will always see the most up-to-date thing that thread A has written. Note however that this logic only works if you have writers who never read, and readers who never write, and if the thing you're writing is an atomic value. As soon as you do a single read-modify-write, you need to go to Interlocked operations or use a Lock.

What is the syntax for Typescript arrow functions with generics?

In case you'd like to do it with async:

const request = async <T>(param1: string, param2: number) => {
  const res = await func();
  return res.response() as T;
}

And a more complex pattern, in case you'd like to wrap your function inside a generic counterpart, such as memoization (Example uses fast-memoize):

const request = memoize(
  async <T>(
    url: string,
    token?: string
  ) => {
    // Perform your code here
  }
);

See how you define the generic after the memoizing function.

How to write an inline IF statement in JavaScript?

I often need to run more code per condition, by using: ( , , ) multiple code elements can execute:

var a = 2;
var b = 3;
var c = 0;

( a < b ?  ( alert('hi'), a=3, b=2, c=a*b ) : ( alert('by'), a=4, b=10, c=a/b ) );

Converting year and month ("yyyy-mm" format) to a date?

The most concise solution if you need the dates to be in Date format:

library(zoo)
month <- "2000-03"
as.Date(as.yearmon(month))
[1] "2000-03-01"

as.Date will fix the first day of each month to a yearmon object for you.

How do I return JSON without using a template in Django?

You could also check the request accept content type as specified in the rfc. That way you can render by default HTML and where your client accept application/jason you can return json in your response without a template being required

How do I make an attributed string using Swift?

It will be really easy to solve your problem with the library I created. It is called Atributika.

let calculatedCoffee: Int = 768
let g = Style("g").font(.boldSystemFont(ofSize: 12)).foregroundColor(.red)
let all = Style.font(.systemFont(ofSize: 12))

let str = "\(calculatedCoffee)<g>g</g>".style(tags: g)
    .styleAll(all)
    .attributedString

label.attributedText = str

768g

You can find it here https://github.com/psharanda/Atributika

Powershell: Get FQDN Hostname

Local Computer FQDN via dotNet class

[System.Net.Dns]::GetHostEntry([string]$env:computername).HostName

or

[System.Net.Dns]::GetHostEntry([string]"localhost").HostName

Reference:

Dns Methods (System.Net)

note: GetHostByName method is obsolete


Local computer FQDN via WMI query

$myFQDN=(Get-WmiObject win32_computersystem).DNSHostName+"."+(Get-WmiObject win32_computersystem).Domain
Write-Host $myFQDN

Reference:

Win32_ComputerSystem class

How can I download a specific Maven artifact in one command line?

To copy artifact in specified location use copy instead of get.

mvn org.apache.maven.plugins:maven-dependency-plugin:3.1.2:copy \
  -DrepoUrl=someRepositoryUrl \
  -Dartifact="com.acme:foo:RELEASE:jar" -Dmdep.stripVersion -DoutputDirectory=/tmp/

Practical uses for AtomicInteger

In Java 8 atomic classes have been extended with two interesting functions:

  • int getAndUpdate(IntUnaryOperator updateFunction)
  • int updateAndGet(IntUnaryOperator updateFunction)

Both are using the updateFunction to perform update of the atomic value. The difference is that the first one returns old value and the second one return the new value. The updateFunction may be implemented to do more complex "compare and set" operations than the standard one. For example it can check that atomic counter doesn't go below zero, normally it would require synchronization, and here the code is lock-free:

    public class Counter {

      private final AtomicInteger number;

      public Counter(int number) {
        this.number = new AtomicInteger(number);
      }

      /** @return true if still can decrease */
      public boolean dec() {
        // updateAndGet(fn) executed atomically:
        return number.updateAndGet(n -> (n > 0) ? n - 1 : n) > 0;
      }
    }

The code is taken from Java Atomic Example.

How to express a One-To-Many relationship in Django

While rolling stone's answer is good, straightforward and functional, I think there are two things it does not solve.

  1. If OP wanted to enforce a phone number cannot belong to both a Dude and a Business
  2. The inescapable feeling of sadness as a result of defining the relationship on the PhoneNumber model and not on the Dude/Business models. When extra terrestrials come to Earth, and we want to add an Alien model, we need to modify the PhoneNumber (assuming the ETs have phone numbers) instead of simply adding a "phone_numbers" field to the Alien model.

Introduce the content types framework, which exposes some objects that allow us to create a "generic foreign key" on the PhoneNumber model. Then, we can define the reverse relationship on Dude and Business

from django.contrib.contenttypes.fields import GenericForeignKey, GenericRelation
from django.contrib.contenttypes.models import ContentType
from django.db import models

class PhoneNumber(models.Model):
    number = models.CharField()

    content_type = models.ForeignKey(ContentType, on_delete=models.CASCADE)
    object_id = models.PositiveIntegerField()
    owner = GenericForeignKey()

class Dude(models.Model):
    numbers = GenericRelation(PhoneNumber)

class Business(models.Model):
    numbers = GenericRelation(PhoneNumber)

See the docs for details, and perhaps check out this article for a quick tutorial.

Also, here is an article that argues against the use of Generic FKs.

How to upload a project to Github

Steps to upload project to git:-

step1-open cmd and change current working directory to your project location.

step2-Initialize your project directory as a Git repository.

$ git init

step3-Add files in your local repository.

$ add .

step4-Commit the files that you've staged in your local repository.

$ git commit -m "First commit"

step5-Copy the remote repository url.

step6-add the remote repository url as origin in your local location.

$ git add origin copied_remote_repository_url

step7-confirm your origin is updated ot not.

$ git remote show origin

step8-push the changed to your github repository

$ git push origin master.

Access-control-allow-origin with multiple domains

In Web.API this attribute can be added using Microsoft.AspNet.WebApi.Cors as detailed at http://www.asp.net/web-api/overview/security/enabling-cross-origin-requests-in-web-api

In MVC you could create a filter attribute to do this work for you:

[AttributeUsage(AttributeTargets.Class | AttributeTargets.Method,
                AllowMultiple = true, Inherited = true)]
public class EnableCorsAttribute : FilterAttribute, IActionFilter {
    private const string IncomingOriginHeader = "Origin";
    private const string OutgoingOriginHeader = "Access-Control-Allow-Origin";
    private const string OutgoingMethodsHeader = "Access-Control-Allow-Methods";
    private const string OutgoingAgeHeader = "Access-Control-Max-Age";

    public void OnActionExecuted(ActionExecutedContext filterContext) {
        // Do nothing
    }

    public void OnActionExecuting(ActionExecutingContext filterContext)
    {
        var isLocal = filterContext.HttpContext.Request.IsLocal;
        var originHeader = 
             filterContext.HttpContext.Request.Headers.Get(IncomingOriginHeader);
        var response = filterContext.HttpContext.Response;

        if (!String.IsNullOrWhiteSpace(originHeader) &&
            (isLocal || IsAllowedOrigin(originHeader))) {
            response.AddHeader(OutgoingOriginHeader, originHeader);
            response.AddHeader(OutgoingMethodsHeader, "GET,POST,OPTIONS");
            response.AddHeader(OutgoingAgeHeader, "3600");
        }
    }

    protected bool IsAllowedOrigin(string origin) {
        // ** replace with your own logic to check the origin header
        return true;
    }
}

Then either enable it for specific actions / controllers:

[EnableCors]
public class SecurityController : Controller {
    // *snip*
    [EnableCors]
    public ActionResult SignIn(Guid key, string email, string password) {

Or add it for all controllers in Global.asax.cs

protected void Application_Start() {
    // *Snip* any existing code

    // Register global filter
    GlobalFilters.Filters.Add(new EnableCorsAttribute());
    RegisterGlobalFilters(GlobalFilters.Filters);

    // *snip* existing code
}

How to change environment's font size?

you can use editor.fontSize into your setting.json file of the editor.

for example :

{
"editor.fontSize": 14
}

How to get coordinates of an svg element?

I was trying to select an area of svg with a rectangle and get all the elements from it. For this, element.getBoundingClientRect() worked perfectly for me. It returns current coordinates of svg elements regardless of whether svg is scaled or transformed.

SOAP client in .NET - references or examples?

I have done quite a bit of what you're talking about, and SOAP interoperability between platforms has one cardinal rule: CONTRACT FIRST. Do not derive your WSDL from code and then try to generate a client on a different platform. Anything more than "Hello World" type functions will very likely fail to generate code, fail to talk at runtime or (my favorite) fail to properly send or receive all of the data without raising an error.

That said, WSDL is complicated, nasty stuff and I avoid writing it from scratch whenever possible. Here are some guidelines for reliable interop of services (using Web References, WCF, Axis2/Java, WS02, Ruby, Python, whatever):

  • Go ahead and do code-first to create your initial WSDL. Then, delete your code and re-generate the server class(es) from the WSDL. Almost every platform has a tool for this. This will show you what odd habits your particular platform has, and you can begin tweaking the WSDL to be simpler and more straightforward. Tweak, re-gen, repeat. You'll learn a lot this way, and it's portable knowledge.
  • Stick to plain old language classes (POCO, POJO, etc.) for complex types. Do NOT use platform-specific constructs like List<> or DataTable. Even PHP associative arrays will appear to work but fail in ways that are difficult to debug across platforms.
  • Stick to basic data types: bool, int, float, string, date(Time), and arrays. Odds are, the more particular you get about a data type, the less agile you'll be to new requirements over time. You do NOT want to change your WSDL if you can avoid it.
  • One exception to the data types above - give yourself a NameValuePair mechanism of some kind. You wouldn't believe how many times a list of these things will save your bacon in terms of flexibility.
  • Set a real namespace for your WSDL. It's not hard, but you might not believe how many web services I've seen in namespace "http://www.tempuri.org". Also, use a URN ("urn:com-myweb-servicename-v1", not a URL-based namespace ("http://servicename.myweb.com/v1". It's not a website, it's an abstract set of characters that defines a logical grouping. I've probably had a dozen people call me for support and say they went to the "website" and it didn't work.

</rant> :)

JSON Invalid UTF-8 middle byte

client text protocol

POST http://127.0.0.1/bom/create HTTP/1.1
Content-Type: application/json
User-Agent: PostmanRuntime/7.25.0
Accept: */*
Postman-Token: 50ecfbfe-741f-4a2b-a3d3-cdf162ada27f
Host: 127.0.0.1
Accept-Encoding: gzip, deflate, br
Connection: keep-alive
Content-Length: 405

{
  "fwoid": 1,
  "list": [
    {
      "bomIndex": "10001",
      "desc": "?GH 1.25 13pin ???? ??",
      "pn": "084.0001.0036",
      "preUse": 1,
      "type": "?? ???-??PCB??"
    },
     {
      "bomIndex": "10002",
      "desc": "????-?????",
      "pn": "Z.08.013.0051",
      "preUse": 1,
      "type": "E060A0302301"
    }
  ]
}
HTTP/1.1 200 OK
Connection: keep-alive
Vary: Origin
Vary: Access-Control-Request-Method
Vary: Access-Control-Request-Headers
Content-Type: application/json
Date: Mon, 01 Jun 2020 11:23:42 GMT
Content-Length: 40

{"code":"0","message":"BOM????"}

a springboot Controller code as below:

@PostMapping("/bom/create")
@ApiOperation(value = "??BOM")
@BusinessOperation(module = "BOM",methods = "??BOM")
public JsonResult save(@RequestBody BOMSaveQuery query)
{
    return bomService.saveBomList(query);
}

when i debug on loopback interface,it works ok. while deploy on internet server via bat command, i got an error

ServletInvocableHandlerMethod - Could not resolve parameter [0] in public XXXController.save(com.h2.mes.query.BOMSaveQuery): JSON parse error: Invalid UTF-8 middle byte 0x3f; nested exception is com.fasterxml.jackson.databind.JsonMappingException: Invalid UTF-8 middle byte 0x3f
 at [Source: (PushbackInputStream); line: 9, column: 32] (through reference chain: com.h2.mes.query.BOMSaveQuery["list"]->java.util.ArrayList[0]->com.h2.mes.vo.BOMVO["type"])
2020-06-01 15:37:50.251 MES [XNIO-1 task-13] WARN  o.s.w.s.m.s.DefaultHandlerExceptionResolver - Resolved [org.springframework.http.converter.HttpMessageNotReadableException: JSON parse error: Invalid UTF-8 middle byte 0x3f; nested exception is com.fasterxml.jackson.databind.JsonMappingException: Invalid UTF-8 middle byte 0x3f
 at [Source: (PushbackInputStream); line: 9, column: 32] (through reference chain: com.h2.mes.query.BOMSaveQuery["list"]->java.util.ArrayList[0]->com.h2.mes.vo.BOMVO["type"])]
2020-06-01 15:37:50.251 MES [XNIO-1 task-13] DEBUG o.s.web.servlet.DispatcherServlet - Completed 400 BAD_REQUEST
2020-06-01 15:37:50.251 MES [XNIO-1 task-13] DEBUG o.s.web.servlet.DispatcherServlet - "ERROR" dispatch for POST "/error", parameters={}

add a jvm arguement works for me. java -Dfile.encoding=UTF-8

Deprecated Gradle features were used in this build, making it incompatible with Gradle 5.0

In my case adding multiDexEnabled true in Android/build/build.gradle file compiled the files.

I will look into removing this in the future, as in the documentation it says 'Before configuring your app to enable use of 64K or more method references, you should take steps to reduce the total number of references called by your app code, including methods defined by your app code or included libraries.'

defaultConfig {
  applicationId "com.peoplesenergyapp"
  minSdkVersion rootProject.ext.minSdkVersion
  targetSdkVersion rootProject.ext.targetSdkVersion
  versionCode 1
  versionName "1.0"
  multiDexEnabled true // <-add this 
}

'Property does not exist on type 'never'

This seems to be similar to this issue: False "Property does not exist on type 'never'" when changing value inside callback with strictNullChecks, which is closed as a duplicate of this issue (discussion): Trade-offs in Control Flow Analysis.

That discussion is pretty long, if you can't find a good solution there you can try this:

if (instance == null) {
    console.log('Instance is null or undefined');
} else {
    console.log(instance!.name); // ok now
}

Access denied for user 'root'@'localhost' (using password: YES) after new installation on Ubuntu

from superuser accepted answer:

sudo mysql -u root
use mysql;
update user set plugin='' where User='root';
flush privileges;
exit;

What is the point of "Initial Catalog" in a SQL Server connection string?

If the user name that is in the connection string has access to more then one database you have to specify the database you want the connection string to connect to. If your user has only one database available then you are correct that it doesn't matter. But it is good practice to put this in your connection string.

Broadcast Receiver within a Service

as your service is already setup, simply add a broadcast receiver in your service:

private final BroadcastReceiver receiver = new BroadcastReceiver() {
   @Override
   public void onReceive(Context context, Intent intent) {
      String action = intent.getAction();
      if(action.equals("android.provider.Telephony.SMS_RECEIVED")){
        //action for sms received
      }
      else if(action.equals(android.telephony.TelephonyManager.ACTION_PHONE_STATE_CHANGED)){
           //action for phone state changed
      }     
   }
};

in your service's onCreate do this:

IntentFilter filter = new IntentFilter();
filter.addAction("android.provider.Telephony.SMS_RECEIVED");
filter.addAction(android.telephony.TelephonyManager.ACTION_PHONE_STATE_CHANGED);
filter.addAction("your_action_strings"); //further more
filter.addAction("your_action_strings"); //further more

registerReceiver(receiver, filter);

and in your service's onDestroy:

unregisterReceiver(receiver);

and you are good to go to receive broadcast for what ever filters you mention in onCreate. Make sure to add any permission if required. for e.g.

<uses-permission android:name="android.permission.RECEIVE_SMS" />

How can I plot a histogram such that the heights of the bars sum to 1 in matplotlib?

Here is another simple solution using np.histogram() method.

myarray = np.random.random(100)
results, edges = np.histogram(myarray, normed=True)
binWidth = edges[1] - edges[0]
plt.bar(edges[:-1], results*binWidth, binWidth)

You can indeed check that the total sums up to 1 with:

> print sum(results*binWidth)
1.0

Turn a number into star rating display using jQuery and CSS

DEMO

You can do it with 2 images only. 1 blank stars, 1 filled stars.

Overlay filled image on the top of the other one. and convert rating number into percentage and use it as width of fillter image.

enter image description here

.containerdiv {
  border: 0;
  float: left;
  position: relative;
  width: 300px;
} 
.cornerimage {
  border: 0;
  position: absolute;
  top: 0;
  left: 0;
  overflow: hidden;
 } 
 img{
   max-width: 300px;
 }

Disable form autofill in Chrome without disabling autocomplete

My solution is based on dsuess user solution, which didn't work in IE for me, because I had to click one more time in the textbox to be able to type in. Therefore I adapted it only to Chrome:

$(window).on('load', function () {
    if (navigator.userAgent.indexOf("Chrome") != -1) {
        $('#myTextBox').attr('readonly', 'true');
        $('#myTextBox').addClass("forceWhiteBackground");
        $('#myTextBox').focus(function () {
            $('#myTextBox').removeAttr('readonly');
            $('#myTextBox').removeClass('forceWhiteBackground');
        });
    }
});

In your css add this:

.forceWhiteBackground {
    background-color:white !important;
}

Find non-ASCII characters in varchar columns using SQL Server

To find which field has invalid characters:

SELECT * FROM Staging.APARMRE1 FOR XML AUTO, TYPE

You can test it with this query:

SELECT top 1 'char 31: '+char(31)+' (hex 0x1F)' field
from sysobjects
FOR XML AUTO, TYPE

The result will be:

Msg 6841, Level 16, State 1, Line 3 FOR XML could not serialize the data for node 'field' because it contains a character (0x001F) which is not allowed in XML. To retrieve this data using FOR XML, convert it to binary, varbinary or image data type and use the BINARY BASE64 directive.

It is very useful when you write xml files and get error of invalid characters when validate it.

What does the "no version information available" error from linux dynamic linker mean?

The "no version information available" means that the library version number is lower on the shared object. For example, if your major.minor.patch number is 7.15.5 on the machine where you build the binary, and the major.minor.patch number is 7.12.1 on the installation machine, ld will print the warning.

You can fix this by compiling with a library (headers and shared objects) that matches the shared object version shipped with your target OS. E.g., if you are going to install to RedHat 3.4.6-9 you don't want to compile on Debian 4.1.1-21. This is one of the reasons that most distributions ship for specific linux distro numbers.

Otherwise, you can statically link. However, you don't want to do this with something like PAM, so you want to actually install a development environment that matches your client's production environment (or at least install and link against the correct library versions.)

Advice you get to rename the .so files (padding them with version numbers,) stems from a time when shared object libraries did not use versioned symbols. So don't expect that playing with the .so.n.n.n naming scheme is going to help (much - it might help if you system has been trashed.)

You last option will be compiling with a library with a different minor version number, using a custom linking script: http://www.redhat.com/docs/manuals/enterprise/RHEL-4-Manual/gnu-linker/scripts.html

To do this, you'll need to write a custom script, and you'll need a custom installer that runs ld against your client's shared objects, using the custom script. This requires that your client have gcc or ld on their production system.

How can I suppress the newline after a print statement?

print didn't transition from statement to function until Python 3.0. If you're using older Python then you can suppress the newline with a trailing comma like so:

print "Foo %10s bar" % baz,

Rebasing a Git merge commit

  • From your merge commit
  • Cherry-pick the new change which should be easy
  • copy your stuff
  • redo the merge and resolve the conflicts by just copying the files from your local copy ;)

exception.getMessage() output with class name

I think you are wrapping your exception in another exception (which isn't in your code above). If you try out this code:

public static void main(String[] args) {
    try {
        throw new RuntimeException("Cannot move file");
    } catch (Exception ex) {
        JOptionPane.showMessageDialog(null, "Error: " + ex.getMessage());
    }
}

...you will see a popup that says exactly what you want.


However, to solve your problem (the wrapped exception) you need get to the "root" exception with the "correct" message. To do this you need to create a own recursive method getRootCause:

public static void main(String[] args) {
    try {
        throw new Exception(new RuntimeException("Cannot move file"));
    } catch (Exception ex) {
        JOptionPane.showMessageDialog(null,
                                      "Error: " + getRootCause(ex).getMessage());
    }
}

public static Throwable getRootCause(Throwable throwable) {
    if (throwable.getCause() != null)
        return getRootCause(throwable.getCause());

    return throwable;
}

Note: Unwrapping exceptions like this however, sort of breaks the abstractions. I encourage you to find out why the exception is wrapped and ask yourself if it makes sense.

Text-align class for inside a table

I guess because CSS already has text-align:right, AFAIK, Bootstrap doesn't have a special class for it.

Bootstrap does have "pull-right" for floating divs, etc. to the right.

Bootstrap 2.3 just came out and added text alignment styles:

Bootstrap 2.3 released (2013-02-07)

Sort a single String in Java

In Java 8 it can be done with:

String s = "edcba".chars()
    .sorted()
    .collect(StringBuilder::new, StringBuilder::appendCodePoint, StringBuilder::append)
    .toString();

A slightly shorter alternative that works with a Stream of Strings of length one (each character in the unsorted String is converted into a String in the Stream) is:

String sorted =
    Stream.of("edcba".split(""))
        .sorted()
        .collect(Collectors.joining());

Angular - ng: command not found

I tried this and everything worked by changing the npm directory.

         mkdir ~/.npm-global
         npm config set prefix '~/.npm-global'
         export PATH=~/.npm-global/bin:$PATH
         source ~/.profile
         npm install -g jshint
         ng --version

Call to undefined function mysql_query() with Login

You are mixing the deprecated mysql extension with mysqli.

Try something like:

$sql = mysqli_query($success, "SELECT * FROM login WHERE username = '".$_POST['username']."' and password = '".md5($_POST['password'])."'");
$row = mysqli_num_rows($sql);

How to read a .properties file which contains keys that have a period character using Shell script

I use simple grep inside function in bash script to receive properties from .properties file.

This properties file I use in two places - to setup dev environment and as application parameters.

I believe that grep may work slow in big loops but it solves my needs when I want to prepare dev environment.

Hope, someone will find this useful.

Example:

File: setup.sh

#!/bin/bash

ENV=${1:-dev}

function prop {
    grep "${1}" env/${ENV}.properties|cut -d'=' -f2
}

docker create \
    --name=myapp-storage \
    -p $(prop 'app.storage.address'):$(prop 'app.storage.port'):9000 \
    -h $(prop 'app.storage.host') \
    -e STORAGE_ACCESS_KEY="$(prop 'app.storage.access-key')" \
    -e STORAGE_SECRET_KEY="$(prop 'app.storage.secret-key')" \
    -e STORAGE_BUCKET="$(prop 'app.storage.bucket')" \
    -v "$(prop 'app.data-path')/storage":/app/storage \
    myapp-storage:latest

docker create \
    --name=myapp-database \
    -p "$(prop 'app.database.address')":"$(prop 'app.database.port')":5432 \
    -h "$(prop 'app.database.host')" \
    -e POSTGRES_USER="$(prop 'app.database.user')" \
    -e POSTGRES_PASSWORD="$(prop 'app.database.pass')" \
    -e POSTGRES_DB="$(prop 'app.database.main')" \
    -e PGDATA="/app/database" \
    -v "$(prop 'app.data-path')/database":/app/database \
    postgres:9.5

File: env/dev.properties

app.data-path=/apps/myapp/

#==========================================================
# Server properties
#==========================================================
app.server.address=127.0.0.70
app.server.host=dev.myapp.com
app.server.port=8080

#==========================================================
# Backend properties
#==========================================================
app.backend.address=127.0.0.70
app.backend.host=dev.myapp.com
app.backend.port=8081
app.backend.maximum.threads=5

#==========================================================
# Database properties
#==========================================================
app.database.address=127.0.0.70
app.database.host=database.myapp.com
app.database.port=5432
app.database.user=dev-user-name
app.database.pass=dev-password
app.database.main=dev-database

#==========================================================
# Storage properties
#==========================================================
app.storage.address=127.0.0.70
app.storage.host=storage.myapp.com
app.storage.port=4569
app.storage.endpoint=http://storage.myapp.com:4569
app.storage.access-key=dev-access-key
app.storage.secret-key=dev-secret-key
app.storage.region=us-east-1
app.storage.bucket=dev-bucket

Usage:

./setup.sh dev

Create a custom event in Java

The following is not exactly the same but similar, I was searching for a snippet to add a call to the interface method, but found this question, so I decided to add this snippet for those who were searching for it like me and found this question:

 public class MyClass
 {
        //... class code goes here

        public interface DataLoadFinishedListener {
            public void onDataLoadFinishedListener(int data_type);
        }

        private DataLoadFinishedListener m_lDataLoadFinished;

        public void setDataLoadFinishedListener(DataLoadFinishedListener dlf){
            this.m_lDataLoadFinished = dlf;
        }



        private void someOtherMethodOfMyClass()
        {
            m_lDataLoadFinished.onDataLoadFinishedListener(1);
        }    
    }

Usage is as follows:

myClassObj.setDataLoadFinishedListener(new MyClass.DataLoadFinishedListener() {
            @Override
            public void onDataLoadFinishedListener(int data_type) {
                }
            });

How do I check the difference, in seconds, between two dates?

import time  
current = time.time()

...job...
end = time.time()
diff = end - current

would that work for you?

TensorFlow, "'module' object has no attribute 'placeholder'"

I had the same problem before after tried to upgrade tensorflow, I solved it by reinstalling Tensorflow and Keras.

pip uninstall tensorflow

pip uninstall keras

Then:

pip install tensorflow

pip install keras

how can I login anonymously with ftp (/usr/bin/ftp)?

Anonymous FTP usage is covered by RFC 1635: How to Use Anonymous FTP:

What is Anonymous FTP?

Anonymous FTP is a means by which archive sites allow general access to their archives of information. These sites create a special account called "anonymous".

Traditionally, this special anonymous user account accepts any string as a password, although it is common to use either the password "guest" or one's electronic mail (e-mail) address. Some archive sites now explicitly ask for the user's e-mail address and will not allow login with the "guest" password. Providing an e-mail address is a courtesy that allows archive site operators to get some idea of who is using their services.

These are general recommendations, though. Each FTP server may have its own guidelines.

For sample use of the ftp command on anonymous FTP access, see appendix A:

atlas.arc.nasa.gov% ftp naic.nasa.gov
Connected to naic.nasa.gov.
220 naic.nasa.gov FTP server (Wed May 4 12:15:15 PDT 1994) ready.
Name (naic.nasa.gov:amarine): anonymous
331 Guest login ok, send your complete e-mail address as password.
Password:
230-----------------------------------------------------------------
230-Welcome to the NASA Network Applications and Info Center Archive
230-
230-     Access to NAIC's online services is also available through:
230-
230-        Gopher         - naic.nasa.gov (port 70)
230-    World-Wide-Web - http://naic.nasa.gov/naic/naic-home.html
230-
230-        If you experience any problems please send email to
230-
230-                    [email protected]
230-
230-                 or call +1 (800) 858-9947
230-----------------------------------------------------------------
230-
230-Please read the file README
230-  it was last modified on Fri Dec 10 13:06:33 1993 - 165 days ago
230 Guest login ok, access restrictions apply.
ftp> cd files/rfc
250-Please read the file README.rfc
250-  it was last modified on Fri Jul 30 16:47:29 1993 - 298 days ago
250 CWD command successful.
ftp> get rfc959.txt
200 PORT command successful.
150 Opening ASCII mode data connection for rfc959.txt (147316 bytes).
226 Transfer complete.
local: rfc959.txt remote: rfc959.txt
151249 bytes received in 0.9 seconds (1.6e+02 Kbytes/s)
ftp> quit
221 Goodbye.
atlas.arc.nasa.gov%

See also the example session at the University of Edinburgh site.

What size do you use for varchar(MAX) in your parameter declaration?

The maximum SqlDbType.VarChar size is 2147483647.

If you would use a generic oledb connection instead of sql, I found here there is also a LongVarChar datatype. Its max size is 2147483647.

cmd.Parameters.Add("@blah", OleDbType.LongVarChar, -1).Value = "very big string";

What is boilerplate code?

Boilerplate in software development can mean different things to different people but generally means the block of code that is used over and over again.

In MEAN stack development, this term refers to code generation through use of template. It's easier than hand coding the entire application from scratch and it gives the code block consistency and fewer bugs as it is clean, tested and proven code and it's open source so it is constantly getting updated or fixed therefore it saves a lot of time as using framework or code generator. For more information about MEAN stack, click here.

I keep getting this error for my simple python program: "TypeError: 'float' object cannot be interpreted as an integer"

range() can only work with integers, but dividing with the / operator always results in a float value:

>>> 450 / 10
45.0
>>> range(450 / 10)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: 'float' object cannot be interpreted as an integer

Make the value an integer again:

for i in range(int(c / 10)):

or use the // floor division operator:

for i in range(c // 10):

Syntax for a for loop in ruby

array.each do |element|
  element.do_stuff
end

or

for element in array do
  element.do_stuff
end

If you need index, you can use this:

array.each_with_index do |element,index|
  element.do_stuff(index)
end

Why is access to the path denied?

I also had the problem, hence me stumbling on this post. I added the following line of code before and after a Copy / Delete.

Delete

File.SetAttributes(file, FileAttributes.Normal);
File.Delete(file);

Copy

File.Copy(file, dest, true);
File.SetAttributes(dest, FileAttributes.Normal);

PHP session handling errors

I had the same error everything was correct like the setting the folder permissions.

It looks like an bug in php in my case because when i delete my PHPSESSID cookie it was working again so aperently something was messed up and the session got removed but the cookie was still active so php had to define the cause differently and checking first if the session file is still they and give another error and not the permission error

Parcelable encountered IOException writing serializable object getactivity()

In my case I had to implement MainActivity as Serializable too. Cause I needed to start a service from my MainActivity :

public class MainActivity extends AppCompatActivity implements Serializable {
    ...
    musicCover = new MusicCover(); // A Serializable Object
    ...
    sIntent = new Intent(MainActivity.this, MusicPlayerService.class);
    sIntent.setAction(MusicPlayerService.ACTION_INITIALIZE_COVER);
    sIntent.putExtra(MusicPlayerService.EXTRA_COVER, musicCover);
    startService(sIntent);
}

How to use particular CSS styles based on screen size / device

@media queries serve this purpose. Here's an example:

@media only screen and (max-width: 991px) and (min-width: 769px){
 /* CSS that should be displayed if width is equal to or less than 991px and larger 
  than 768px goes here */
}

@media only screen and (max-width: 991px){
 /* CSS that should be displayed if width is equal to or less than 991px goes here */
}

IllegalArgumentException or NullPointerException for a null parameter?

You should be using IllegalArgumentException (IAE), not NullPointerException (NPE) for the following reasons:

First, the NPE JavaDoc explicitly lists the cases where NPE is appropriate. Notice that all of them are thrown by the runtime when null is used inappropriately. In contrast, the IAE JavaDoc couldn't be more clear: "Thrown to indicate that a method has been passed an illegal or inappropriate argument." Yup, that's you!

Second, when you see an NPE in a stack trace, what do you assume? Probably that someone dereferenced a null. When you see IAE, you assume the caller of the method at the top of the stack passed in an illegal value. Again, the latter assumption is true, the former is misleading.

Third, since IAE is clearly designed for validating parameters, you have to assume it as the default choice of exception, so why would you choose NPE instead? Certainly not for different behavior -- do you really expect calling code to catch NPE's separately from IAE and do something different as a result? Are you trying to communicate a more specific error message? But you can do that in the exception message text anyway, as you should for all other incorrect parameters.

Fourth, all other incorrect parameter data will be IAE, so why not be consistent? Why is it that an illegal null is so special that it deserves a separate exception from all other types of illegal arguments?

Finally, I accept the argument given by other answers that parts of the Java API use NPE in this manner. However, the Java API is inconsistent with everything from exception types to naming conventions, so I think just blindly copying (your favorite part of) the Java API isn't a good enough argument to trump these other considerations.

How to get the version of ionic framework?

The method version on ionic object returns the current version in string format.

What is web.xml file and what are all things can I do with it?

  1. No, there isn't anything that should be avoided
  2. The parameters related to performance are not in web.xml they are in the servlet container configuration files (server.xml on tomcat)
  3. No. But the default servlet (mapped in a web.xml at a common location in your servlet container) should preferably disable file listings (so that users don't see the contents of your web folders):

    listings true

What is "Connect Timeout" in sql server connection string?

Gets the time to wait while trying to establish a connection before terminating the attempt and generating an error. (MSDN, SqlConnection.ConnectionTimeout Property, 2013)

Submitting the value of a disabled input field

I wanna Disable an Input Field on a form and when i submit the form the values from the disabled form is not submitted.

Use Case: i am trying to get Lat Lng from Google Map and wanna Display it.. but dont want the user to edit it.

You can use the readonly property in your input field

<input type="text" readonly="readonly" />

How to use a jQuery plugin inside Vue

There's a much, much easier way. Do this:

MyComponent.vue

<template>
  stuff here
</template>
<script>
  import $ from 'jquery';
  import 'selectize';

  $(function() {
      // use jquery
      $('body').css('background-color', 'orange');

      // use selectize, s jquery plugin
      $('#myselect').selectize( options go here );
  });

</script>

Make sure JQuery is installed first with npm install jquery. Do the same with your plugin.

Understanding MongoDB BSON Document size limit

I have not yet seen a problem with the limit that did not involve large files stored within the document itself. There are already a variety of databases which are very efficient at storing/retrieving large files; they are called operating systems. The database exists as a layer over the operating system. If you are using a NoSQL solution for performance reasons, why would you want to add additional processing overhead to the access of your data by putting the DB layer between your application and your data?

JSON is a text format. So, if you are accessing your data through JSON, this is especially true if you have binary files because they have to be encoded in uuencode, hexadecimal, or Base 64. The conversion path might look like

binary file <> JSON (encoded) <> BSON (encoded)

It would be more efficient to put the path (URL) to the data file in your document and keep the data itself in binary.

If you really want to keep these files of unknown length in your DB, then you would probably be better off putting these in GridFS and not risking killing your concurrency when the large files are accessed.

How to set or change the default Java (JDK) version on OS X?

This answer is an attempt to address: how to control java version system-wide (not just in currently running shell) when several versions of JDK are installed for development purposes on macOS El Capitan or newer (Sierra, High Sierra, Mojave). As far as I can tell, none of the current answers do that (*).

As a developer, I use several JDKs, and I want to switch from one to the other easily. Usually I have the latest stable one for general use, and others for tests. But I don't want the system (e.g. when I start my IDE) to use the latest "early access" version I have for now. I want to control system's default, and that should be latest stable.

The following approach works with Java 7 to 12 at least (early access at the time of this writing), with Oracle JDK or OpenJDK (including builds by AdoptOpenJDK produced after mid-October 2018).

Solution without 3rd party tools:

  • leave all JDKs at their default location, under /Library/Java/JavaVirtualMachines. The system will pick the highest version by default.
  • To exclude a JDK from being picked by default, rename its Contents/Info.plist to Info.plist.disabled. That JDK can still be used when $JAVA_HOME points to it, or explicitly referenced in a script or configuration. It will simply be ignored by system's java command.

System launcher will use the JDK with highest version among those that have an Info.plist file.

When working in a shell with alternate JDK, pick your method among existing answers (jenv, or custom aliases/scripts around /usr/libexec/java_home, etc).


Details of investigation in this gist.


(*) Current answers are either obsolete (no longer valid for macOS El Capitan or Sierra), or only address a single JDK, or do not address the system-wide aspect. Many explain how to change $JAVA_HOME, but this only affects the current shell and what is launched from there. It won't affect an application started from OS launcher (unless you change the right file and logout/login, which is tedious). Same for jenv, it's cool and all, but as far as I can tell it merely changes environment variables, so it has the same limitation.

What's the difference between SHA and AES encryption?

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

AES Reference

Best algorithm for detecting cycles in a directed graph

https://mathoverflow.net/questions/16393/finding-a-cycle-of-fixed-length I like this solution the best specially for 4 length:)

Also phys wizard says u have to do O(V^2). I believe that we need only O(V)/O(V+E). If the graph is connected then DFS will visit all nodes. If the graph has connected sub graphs then each time we run a DFS on a vertex of this sub graph we will find the connected vertices and wont have to consider these for the next run of the DFS. Therefore the possibility of running for each vertex is incorrect.

How do I add a library path in cmake?

You had better use find_library command instead of link_directories. Concretely speaking there are two ways:

  1. designate the path within the command

    find_library(NAMES gtest PATHS path1 path2 ... pathN)

  2. set the variable CMAKE_LIBRARY_PATH

    set(CMAKE_LIBRARY_PATH path1 path2)
    find_library(NAMES gtest)

the reason is as flowings:

Note This command is rarely necessary and should be avoided where there are other choices. Prefer to pass full absolute paths to libraries where possible, since this ensures the correct library will always be linked. The find_library() command provides the full path, which can generally be used directly in calls to target_link_libraries(). Situations where a library search path may be needed include: Project generators like Xcode where the user can switch target architecture at build time, but a full path to a library cannot be used because it only provides one architecture (i.e. it is not a universal binary).

Libraries may themselves have other private library dependencies that expect to be found via RPATH mechanisms, but some linkers are not able to fully decode those paths (e.g. due to the presence of things like $ORIGIN).

If a library search path must be provided, prefer to localize the effect where possible by using the target_link_directories() command rather than link_directories(). The target-specific command can also control how the search directories propagate to other dependent targets.

how can the textbox width be reduced?

<input type='text' 
       name='t1'
       id='t1'
       maxlength=10
       placeholder='typing some text' >
<p></p>

This is the text box, it has a fixed length of 10 characters, and if you can try but this text box does not contain maximum length 10 character

How to create Toast in Flutter?

use this dependency: toast: ^0.1.3 then import the dependency of toast in the page : import 'package:toast/toast.dart'; then on onTap() of the widget: Toast.show("Toast plugin app", context,duration: Toast.LENGTH_SHORT, gravity: Toast.BOTTOM);

horizontal scrollbar on top and bottom of table

Expanding on StanleyH's answer, and trying to find the minimum required, here is what I implemented:

JavaScript (called once from somewhere like $(document).ready()):

function doubleScroll(){
        $(".topScrollVisible").scroll(function(){
            $(".tableWrapper")
                .scrollLeft($(".topScrollVisible").scrollLeft());
        });
        $(".tableWrapper").scroll(function(){
            $(".topScrollVisible")
                .scrollLeft($(".tableWrapper").scrollLeft());
        });
}

HTML (note that the widths will change the scroll bar length):

<div class="topScrollVisible" style="overflow-x:scroll">
    <div class="topScrollTableLength" style="width:1520px; height:20px">
    </div>
</div>
<div class="tableWrapper" style="overflow:auto; height:100%;">
    <table id="myTable" style="width:1470px" class="myTableClass">
...
    </table>

That's it.

Transactions in .net

if you just need it for db-related stuff, some OR Mappers (e.g. NHibernate) support transactinos out of the box per default.

404 Not Found The requested URL was not found on this server

For me, using OS X Catalina: Changing from AllowOverride None to AllowOverride All is the one that works.

httpd.conf is located on /etc/apache2/httpd.conf.

Env: PHP7. MySQL8.

Convert Xml to Table SQL Server

The sp_xml_preparedocument stored procedure will parse the XML and the OPENXML rowset provider will show you a relational view of the XML data.

For details and more examples check the OPENXML documentation.

As for your question,

DECLARE @XML XML
SET @XML = '<rows><row>
    <IdInvernadero>8</IdInvernadero>
    <IdProducto>3</IdProducto>
    <IdCaracteristica1>8</IdCaracteristica1>
    <IdCaracteristica2>8</IdCaracteristica2>
    <Cantidad>25</Cantidad>
    <Folio>4568457</Folio>
</row>
<row>
    <IdInvernadero>3</IdInvernadero>
    <IdProducto>3</IdProducto>
    <IdCaracteristica1>1</IdCaracteristica1>
    <IdCaracteristica2>2</IdCaracteristica2>
    <Cantidad>72</Cantidad>
    <Folio>4568457</Folio>
</row></rows>'

DECLARE @handle INT  
DECLARE @PrepareXmlStatus INT  

EXEC @PrepareXmlStatus= sp_xml_preparedocument @handle OUTPUT, @XML  

SELECT  *
FROM    OPENXML(@handle, '/rows/row', 2)  
    WITH (
    IdInvernadero INT,
    IdProducto INT,
    IdCaracteristica1 INT,
    IdCaracteristica2 INT,
    Cantidad INT,
    Folio INT
    )  


EXEC sp_xml_removedocument @handle 

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

Here is a script I run to restart adb (Android Debug Bridge) server:

#!/usr/bin/env bash

## Summary: restart adb (Android Debug Brdige) server.

## adb binary full path
ADB_BIN=./adb


if pgrep adb >/dev/null 2>&1
then
    echo "adb is running"
    echo "terminating adb ..."
    $ADB_BIN kill-server
    if pgrep adb >/dev/null 2>&1
    then
        echo "did not work"
        echo "kill adb processes by killall"
        killall -9 adb
    else
        echo "terminated"
    fi
else
    echo "adb is not running"
fi

echo "starting adb ..."

$ADB_BIN start-server

echo "adb process:"

echo `pgrep adb`

echo "done"

# END

How to pass data in the ajax DELETE request other than headers

Read this Bug Issue: http://bugs.jquery.com/ticket/11586

Quoting the RFC 2616 Fielding

The DELETE method requests that the origin server delete the resource identified by the Request-URI.

So you need to pass the data in the URI

$.ajax({
    url: urlCall + '?' + $.param({"Id": Id, "bolDeleteReq" : bolDeleteReq}),
    type: 'DELETE',
    success: callback || $.noop,
    error: errorCallback || $.noop
});

How to write data with FileOutputStream without losing old data?

Use the constructor that takes a File and a boolean

FileOutputStream(File file, boolean append) 

and set the boolean to true. That way, the data you write will be appended to the end of the file, rather than overwriting what was already there.

What are the new features in C++17?

Language features:

Templates and Generic Code

Lambda

Attributes

Syntax cleanup

Cleaner multi-return and flow control

  • Structured bindings

    • Basically, first-class std::tie with auto
    • Example:
      • const auto [it, inserted] = map.insert( {"foo", bar} );
      • Creates variables it and inserted with deduced type from the pair that map::insert returns.
    • Works with tuple/pair-likes & std::arrays and relatively flat structs
    • Actually named structured bindings in standard
  • if (init; condition) and switch (init; condition)

    • if (const auto [it, inserted] = map.insert( {"foo", bar} ); inserted)
    • Extends the if(decl) to cases where decl isn't convertible-to-bool sensibly.
  • Generalizing range-based for loops

    • Appears to be mostly support for sentinels, or end iterators that are not the same type as begin iterators, which helps with null-terminated loops and the like.
  • if constexpr

    • Much requested feature to simplify almost-generic code.

Misc

Library additions:

Data types

Invoke stuff

File System TS v1

New algorithms

  • for_each_n

  • reduce

  • transform_reduce

  • exclusive_scan

  • inclusive_scan

  • transform_exclusive_scan

  • transform_inclusive_scan

  • Added for threading purposes, exposed even if you aren't using them threaded

Threading

(parts of) Library Fundamentals TS v1 not covered above or below

Container Improvements

Smart pointer changes

Other std datatype improvements:

Misc

Traits

Deprecated

Isocpp.org has has an independent list of changes since C++14; it has been partly pillaged.

Naturally TS work continues in parallel, so there are some TS that are not-quite-ripe that will have to wait for the next iteration. The target for the next iteration is C++20 as previously planned, not C++19 as some rumors implied. C++1O has been avoided.

Initial list taken from this reddit post and this reddit post, with links added via googling or from the above isocpp.org page.

Additional entries pillaged from SD-6 feature-test list.

clang's feature list and library feature list are next to be pillaged. This doesn't seem to be reliable, as it is C++1z, not C++17.

these slides had some features missing elsewhere.

While "what was removed" was not asked, here is a short list of a few things ((mostly?) previous deprecated) that are removed in C++17 from C++:

Removed:

There were rewordings. I am unsure if these have any impact on code, or if they are just cleanups in the standard:

Papers not yet integrated into above:

  • P0505R0 (constexpr chrono)

  • P0418R2 (atomic tweaks)

  • P0512R0 (template argument deduction tweaks)

  • P0490R0 (structured binding tweaks)

  • P0513R0 (changes to std::hash)

  • P0502R0 (parallel exceptions)

  • P0509R1 (updating restrictions on exception handling)

  • P0012R1 (make exception specifications be part of the type system)

  • P0510R0 (restrictions on variants)

  • P0504R0 (tags for optional/variant/any)

  • P0497R0 (shared ptr tweaks)

  • P0508R0 (structured bindings node handles)

  • P0521R0 (shared pointer use count and unique changes?)

Spec changes:

Further reference:

Redis: Show database size/size for keys

You might find it very useful to sample Redis keys and group them by type. Salvatore has written a tool called redis-sampler that issues about 10000 RANDOMKEY commands followed by a TYPE on retrieved keys. In a matter of seconds, or minutes, you should get a fairly accurate view of the distribution of key types.

I've written an extension (unfortunately not anywhere open-source because it's work related), that adds a bit of introspection of key names via regexs that give you an idea of what kinds of application keys (according to whatever naming structure you're using), are stored in Redis. Combined with the more general output of redis-sampler, this should give you an extremely good idea of what's going on.

How can I print literal curly-brace characters in a string and also use .format on it?

If you are going to be doing this a lot, it might be good to define a utility function that will let you use arbitrary brace substitutes instead, like

def custom_format(string, brackets, *args, **kwargs):
    if len(brackets) != 2:
        raise ValueError('Expected two brackets. Got {}.'.format(len(brackets)))
    padded = string.replace('{', '{{').replace('}', '}}')
    substituted = padded.replace(brackets[0], '{').replace(brackets[1], '}')
    formatted = substituted.format(*args, **kwargs)
    return formatted

>>> custom_format('{{[cmd]} process 1}', brackets='[]', cmd='firefox.exe')
'{{firefox.exe} process 1}'

Note that this will work either with brackets being a string of length 2 or an iterable of two strings (for multi-character delimiters).

What primitive data type is time_t?

It's platform-specific. But you can cast it to a known type.

printf("%lld\n", (long long) time(NULL));

Java: How to access methods from another class

I have another solution. If Alpha and Beta are your only extra class then why not make a static variable with the image of the class.

Like in Alpha class :

public class Alpha{
        public static Alpha alpha;
        public Alpha(){
                this.alpha = this;
}

Now you you can call the function in Beta class by just using these lines :

new Alpha();
Alpha.alpha.DoSomethingAlpha();

How do you completely remove the button border in wpf?

You may already know that putting your Button inside of a ToolBar gives you this behavior, but if you want something that will work across ALL current themes with any sort of predictability, you'll need to create a new ControlTemplate.

Prashant's solution does not work with a Button not in a toolbar when the Button has focus. It also doesn't work 100% with the default theme in XP -- you can still see faint gray borders when your container Background is white.

javascript Unable to get property 'value' of undefined or null reference

The issue is how you're attempting to get the value. Things like...

if ( document.frm_new_user_request.u_isid.value == '' )

won't work. You need to find the element you want to get the value of first. It's not quite like a server side language where you can type in an object's reference name and a period to get or assign values.

document.getElementById('[id goes here]').value;

will work. Note: JavaScript is case-sensitive

I would recommend using:

var variablename = document.getElementById('[id goes here]');

or

var variablename = document.getElementById('[id goes here]').value;

How to store a dataframe using Pandas

Pandas DataFrames have the to_pickle function which is useful for saving a DataFrame:

import pandas as pd

a = pd.DataFrame({'A':[0,1,0,1,0],'B':[True, True, False, False, False]})
print a
#    A      B
# 0  0   True
# 1  1   True
# 2  0  False
# 3  1  False
# 4  0  False

a.to_pickle('my_file.pkl')

b = pd.read_pickle('my_file.pkl')
print b
#    A      B
# 0  0   True
# 1  1   True
# 2  0  False
# 3  1  False
# 4  0  False

Make a div into a link

An option that hasn't been mentioned is using flex. By applying flex: 1 to the a tag, it expands to fit the container.

_x000D_
_x000D_
div {_x000D_
  height: 100px;_x000D_
  width: 100px;_x000D_
  display: flex;_x000D_
  border: 1px solid;_x000D_
}_x000D_
_x000D_
a {_x000D_
  flex: 1;_x000D_
}
_x000D_
<div>_x000D_
  <a href="http://google.co.uk">Link</a>_x000D_
</div>
_x000D_
_x000D_
_x000D_

Access Control Request Headers, is added to header in AJAX request with jQuery

This code below works for me. I always use only single quotes, and it works fine. I suggest you should use only single quotes or only double quotes, but not mixed up.

$.ajax({
    url: 'YourRestEndPoint',
    headers: {
        'Authorization':'Basic xxxxxxxxxxxxx',
        'X-CSRF-TOKEN':'xxxxxxxxxxxxxxxxxxxx',
        'Content-Type':'application/json'
    },
    method: 'POST',
    dataType: 'json',
    data: YourData,
    success: function(data){
      console.log('succes: '+data);
    }
  });

Predict() - Maybe I'm not understanding it

Thanks Hong, that was exactly the problem I was running into. The error you get suggests that the number of rows is wrong, but the problem is actually that the model has been trained using a command that ends up with the wrong names for parameters.

This is really a critical detail that is entirely non-obvious for lm and so on. Some of the tutorial make reference to doing lines like lm(olive$Area@olive$Palmitic) - ending up with variable names of olive$Area NOT Area, so creating an entry using anewdata<-data.frame(Palmitic=2) can't then be used. If you use lm(Area@Palmitic,data=olive) then the variable names are right and prediction works.

The real problem is that the error message does not indicate the problem at all:

Warning message: 'anewdata' had 1 rows but variable(s) found to have X rows

Android open pdf file

Kotlin version below (Updated version of @paul-burke response:

fun openPDFDocument(context: Context, filename: String) {
    //Create PDF Intent
    val pdfFile = File(Environment.getExternalStorageDirectory().absolutePath + "/" + filename)
    val pdfIntent = Intent(Intent.ACTION_VIEW)
    pdfIntent.setDataAndType(Uri.fromFile(pdfFile), "application/pdf")
    pdfIntent.setFlags(Intent.FLAG_ACTIVITY_NO_HISTORY)

    //Create Viewer Intent
    val viewerIntent = Intent.createChooser(pdfIntent, "Open PDF")
    context.startActivity(viewerIntent)
}

Get folder up one level

You can try

echo realpath(__DIR__ . DIRECTORY_SEPARATOR . '..'); 

HTML/Javascript change div content

you can use following helper function:

function content(divSelector, value) {
    document.querySelector(divSelector).innerHTML = value;
}

content('#content',"whatever");

Where #content must be valid CSS selector

Here is working example.


Additionaly - today (2018.07.01) I made speed comparison for jquery and pure js solutions ( MacOs High Sierra 10.13.3 on Chrome 67.0.3396.99 (64-bit), Safari 11.0.3 (13604.5.6), Firefox 59.0.2 (64-bit) ):

document.getElementById("content").innerHTML = "whatever"; // pure JS
$('#content').html('whatever');                            // jQuery

enter image description here

The jquery solution was slower than pure js solution: 69% on firefox, 61% on safari, 56% on chrome. The fastest browser for pure js was firefox with 560M operations per second, the second was safari 426M, and slowest was chrome 122M.

So the winners are pure js and firefox (3x faster than chrome!)

You can test it in your machine: https://jsperf.com/js-jquery-html-content-change

Why am I getting this error: No mapping specified for the following EntitySet/AssociationSet - Entity1?

Update Model from Database doesn't works for me.

I had to remove the conflicted entity, then execute Update Model from Database, lastly rebuild the solution. After that, everything works fine.

Scale an equation to fit exact page width

The graphicx package provides the command \resizebox{width}{height}{object}:

\documentclass{article}
\usepackage{graphicx}
\begin{document}
\hrule
%%%
\makeatletter%
\setlength{\@tempdima}{\the\columnwidth}% the, well columnwidth
\settowidth{\@tempdimb}{(\ref{Equ:TooLong})}% the width of the "(1)"
\addtolength{\@tempdima}{-\the\@tempdimb}% which cannot be used for the math
\addtolength{\@tempdima}{-1em}%
% There is probably some variable giving the required minimal distance
% between math and label, but because I do not know it I used 1em instead.
\addtolength{\@tempdima}{-1pt}% distance must be greater than "1em"
\xdef\Equ@width{\the\@tempdima}% space remaining for math
\begin{equation}%
\resizebox{\Equ@width}{!}{$\displaystyle{% to get everything inside "big"
 A+B+C+D+E+F+G+H+I+J+K+L+M+N+O+P+Q+R+S+T+U+V+W+X+Y+Z}$}%
\label{Equ:TooLong}%
\end{equation}%
\makeatother%
%%%
\hrule
\end{document}

Migration: Cannot add foreign key constraint

In my case, I was referencing an integer id column on a string user_id column. I changed:

$table->string('user_id')

to:

$table->integer('user_id')->unsigned();

Hope it helps someone!

Capture Signature using HTML5 and iPad

The options already listed are very good, however here a few more on this topic that I've researched and came across.

1) http://perfectionkills.com/exploring-canvas-drawing-techniques/
2) http://mcc.id.au/2010/signature.html
3) https://zipso.net/a-simple-touchscreen-sketchpad-using-javascript-and-html5/

And as always you may want to save the canvas to image:
http://www.html5canvastutorials.com/advanced/html5-canvas-save-drawing-as-an-image/

good luck and happy signing

PHP7 : install ext-dom issue

simply run

sudo apt install php-xml

its worked for me

Rails has_many with alias name

You could do this two different ways. One is by using "as"

has_many :tasks, :as => :jobs

or

def jobs
     self.tasks
end

Obviously the first one would be the best way to handle it.

Number of elements in a javascript object

if you are already using jQuery in your build just do this:

$(yourObject).length

It works nicely for me on objects, and I already had jQuery as a dependancy.

ToList().ForEach in Linq

Try this:

foreach (var dept in employees.SelectMany(e => e.Departments))
{
   dept.SomeProperty = null;
   collection.Add(dept);
}

How do I negate a test with regular expressions in a bash script?

Yes you can negate the test as SiegeX has already pointed out.

However you shouldn't use regular expressions for this - it can fail if your path contains special characters. Try this instead:

[[ ":$PATH:" != *":$1:"* ]]

(Source)

DataSet panel (Report Data) in SSRS designer is gone

If you are using BIDS with SQL 2008 R2 you can only get the "Report Data" menu by clicking inside the actual report layout itself.

  1. Click inside the actual report layout.

  2. Now select "View" from the main menu bar.

  3. Now select "Report Data" which is the last item.

Array of PHP Objects

Although all the answers given are correct, in fact they do not completely answer the question which was about using the [] construct and more generally filling the array with objects.

A more relevant answer can be found in how to build arrays of objects in PHP without specifying an index number? which clearly shows how to solve the problem.

Remove rows not .isin('X')

All you have to do is create a subset of your dataframe where the isin method evaluates to False:

df = df[df['Column Name'].isin(['Value']) == False]

ORA-01950: no privileges on tablespace 'USERS'

You cannot insert data because you have a quota of 0 on the tablespace. To fix this, run

ALTER USER <user> quota unlimited on <tablespace name>;

or

ALTER USER <user> quota 100M on <tablespace name>;

as a DBA user (depending on how much space you need / want to grant).

function is not defined error in Python

It works for me:

>>> def pyth_test (x1, x2):
...     print x1 + x2
...
>>> pyth_test(1,2)
3

Make sure you define the function before you call it.

Iterating each character in a string using Python

Just to make a more comprehensive answer, the C way of iterating over a string can apply in Python, if you really wanna force a square peg into a round hole.

i = 0
while i < len(str):
    print str[i]
    i += 1

But then again, why do that when strings are inherently iterable?

for i in str:
    print i

Can I stop 100% Width Text Boxes from extending beyond their containers?

box-sizing support is pretty good actually: http://caniuse.com/#search=box-sizing

So unless you target IE7, you should be able to solve this kind of issues using this property. A layer such as sass or less makes it easier to handle prefixed rules like that, btw.

Getting path of captured image in Android using camera intent

Try this method to get path of original image captured by camera.

public String getOriginalImagePath() {
        String[] projection = { MediaStore.Images.Media.DATA };
        Cursor cursor = getActivity().managedQuery(
                MediaStore.Images.Media.EXTERNAL_CONTENT_URI,
                projection, null, null, null);
        int column_index_data = cursor
                .getColumnIndexOrThrow(MediaStore.Images.Media.DATA);
        cursor.moveToLast();

        return cursor.getString(column_index_data);
    }

This method will return path of the last image captured by camera. So this path would be of original image not of thumbnail bitmap.

(unicode error) 'unicodeescape' codec can't decode bytes in position 2-3: truncated \UXXXXXXXX escape

You can just put r in front of the string with your actual path, which denotes a raw string. For example:

data = open(r"C:\Users\miche\Documents\school\jaar2\MIK\2.6\vektis_agb_zorgverlener")

Simple DateTime sql query

Others have already said that date literals in SQL Server require being surrounded with single quotes, but I wanted to add that you can solve your month/day mixup problem two ways (that is, the problem where 25 is seen as the month and 5 the day) :

  1. Use an explicit Convert(datetime, 'datevalue', style) where style is one of the numeric style codes, see Cast and Convert. The style parameter isn't just for converting dates to strings but also for determining how strings are parsed to dates.

  2. Use a region-independent format for dates stored as strings. The one I use is 'yyyymmdd hh:mm:ss', or consider ISO format, yyyy-mm-ddThh:mi:ss.mmm. Based on experimentation, there are NO other language-invariant format string. (Though I think you can include time zone at the end, see the above link).

How to select an element by classname using jqLite?

If elem.find() is not working for you, check that you are including JQuery script before angular script....

How to change column datatype from character to numeric in PostgreSQL 8.4

If your VARCHAR column contains empty strings (which are not the same as NULL for PostgreSQL as you might recall) you will have to use something in the line of the following to set a default:

ALTER TABLE presales ALTER COLUMN code TYPE NUMERIC(10,0)
            USING COALESCE(NULLIF(code, '')::NUMERIC, 0);

(found with the help of this answer)

Where can I download the jar for org.apache.http package?

You can add org.apache.http by using below code in app:Build gradle

dependencies {
    compile 'org.apache.httpcomponents:httpclient:4.5'
}

Compare one String with multiple values in one expression

Remember in Java a quoted String is still a String object. Therefore you can use the String function contains() to test for a range of Strings or integers using this method:

if ("A C Viking G M Ocelot".contains(mAnswer)) {...}

for numbers it's a tad more involved but still works:

if ("1 4 5 9 10 17 23 96457".contains(String.valueOf(mNumAnswer))) {...} 

Posting JSON Data to ASP.NET MVC

I see everyone here "took the long route!". As long as you are using MVC, I strongly recommend you to use the easiest method over all which is Newtonsoft.JSON... Also If you dont wanna use libraries check the answer links below. I took a good research time for this to solve the issue for my self and these are the solutions I found;

First implement the Newtonsoft.Json:

using Newtonsoft.Json;

Prepare your Ajax request:

$.ajax({
    dataType: "json",
    contentType: "application/json",            
    type: 'POST',
    url: '/Controller/Action',
    data: { 'items': JSON.stringify(lineItems), 'id': documentId }
});

Then go for your result class:

public ActionResult SaveData(string incoming, int documentId){
    // DeSerialize into your Model as your Model Array
    LineItem[] jsr = JsonConvert.DeserializeObject<LineItem[]>(Temp);
    foreach(LineItem item in jsr){
        // save some stuff
    }
    return Json(new { success = true, message = "Some message" });
}

See the trick up there? Instead of using JsonResult I used regular ActionResult with a string which includes json string. Then deserialized into my Model so I can use this in any action method I have.

Plus sides of this method is :

  1. Easier to pass between actions,
  2. Lesser and more clear usage of code,
  3. No need to change your model,
  4. Simple implementation with JSON.stringify(Model)
  5. Passing only string

Down sides of this method is :

  1. Passing only string
  2. Deserialization process

Also check these questions and answers which are really helpfull:

https://stackoverflow.com/a/45682516/861019

another method :

https://stackoverflow.com/a/31656160/861019

and another method :

https://stackoverflow.com/a/50787450/861019

How do you uninstall all dependencies listed in package.json (NPM)?

Even you don't need to run the loop for that.

You can delete all the node_modules by using the only single command:-

npm uninstall `ls -1 node_modules | tr '/\n' ' '`

How do I join two SQLite tables in my Android application?

You need rawQuery method.

Example:

private final String MY_QUERY = "SELECT * FROM table_a a INNER JOIN table_b b ON a.id=b.other_id WHERE b.property_id=?";

db.rawQuery(MY_QUERY, new String[]{String.valueOf(propertyId)});

Use ? bindings instead of putting values into raw sql query.

How to delete multiple files at once in Bash on Linux?

I am not a linux guru, but I believe you want to pipe your list of output files to xargs rm -rf. I have used something like this in the past with good results. Test on a sample directory first!

EDIT - I might have misunderstood, based on the other answers that are appearing. If you can use wildcards, great. I assumed that your original list that you displayed was generated by a program to give you your "selection", so I thought piping to xargs would be the way to go.

How to use boolean datatype in C?

C99 has a boolean datatype, actually, but if you must use older versions, just define a type:

typedef enum {false=0, true=1} bool;

How to extract week number in sql

After converting your varchar2 date to a true date datatype, then convert back to varchar2 with the desired mask:

to_char(to_date('01/02/2012','MM/DD/YYYY'),'WW')

If you want the week number in a number datatype, you can wrap the statement in to_number():

to_number(to_char(to_date('01/02/2012','MM/DD/YYYY'),'WW'))

However, you have several week number options to consider:

WW  Week of year (1-53) where week 1 starts on the first day of the year and continues to the seventh day of the year.
W   Week of month (1-5) where week 1 starts on the first day of the month and ends on the seventh.
IW  Week of year (1-52 or 1-53) based on the ISO standard.

Express-js can't GET my static files, why?

if your setup

myApp
  |
  |__ public
  |     |
  |     |__  stylesheets
  |     |     |
  |     |     |__ style.css
  |     |
  |     |___ img
  |           |
  |           |__ logo.png
  |
  |__ app.js

then,
put in app.js

app.use('/static', express.static('public'));

and refer to your style.css: (in some .pug file):

link(rel='stylesheet', href='/static/stylesheets/style.css')

Spring MVC UTF-8 Encoding

In addition to Benjamin's answer (which I've only skimmed), you need to make sure that your files are actually stored using the proper encoding (that would be UTF-8 for source code, JSPs etc., but note that Java Properties files must be encoded as ISO 8859-1 by definition).

The problem with this is that it's not possible to tell what encoding has been used to store a file. Your only option is to open the file using a specific encoding, and checking whether or not the content makes sense. You can also try to convert the file from the assumed encoding to the desired encoding using iconv - if that produces an error, your assumption was incorrect. So if you assume that hello.jsp is encoded as UTF-8, run "iconv -f UTF-16 -t UTF-8 hello.jsp" and check for errors.

If you should find out that your files are not properly encoded, you need to find out why. It's probably the editor or IDE you used to create the file. In case of Eclipse (and STS), make sure the Text File Encoding (Preferences / General / Workspace) is set to UTF-8 (it unfortunately defaults to your system's platform encoding).

What makes encoding problems so difficult to debug is that there's so many components involved (text editor, borwser, plus each and every software component in between, in some cases including a database), and each of them has the potential to introduce an error.

How to get HTTP Response Code using Selenium WebDriver

Not sure this is what you're looking for, but I had a bit different goal is to check if remote image exists and I will not have 403 error, so you could use something like below:

public static boolean linkExists(String URLName){
    try {
        HttpURLConnection.setFollowRedirects(false);
        HttpURLConnection con = (HttpURLConnection) new URL(URLName).openConnection();
        con.setRequestMethod("HEAD");
        return (con.getResponseCode() == HttpURLConnection.HTTP_OK);
    }
    catch (Exception e) {
        e.printStackTrace();
        return false;
    }
}

Binding to static property

Look at my project CalcBinding, which provides to you writing complex expressions in Path property value, including static properties, source properties, Math and other. So, you can write this:

<TextBox Text="{c:Binding local:VersionManager.FilterString}"/>

Goodluck!

What is the difference between screenX/Y, clientX/Y and pageX/Y?

The difference between those will depend largely on what browser you are currently referring to. Each one implements these properties differently, or not at all. Quirksmode has great documentation regarding browser differences in regards to W3C standards like the DOM and JavaScript Events.

Using array map to filter results with if conditional

You could use flatMap. It can filter and map in one.

$scope.appIds = $scope.applicationsHere.flatMap(obj => obj.selected ? obj.id : [])

Best way to create an empty map in Java

If you need an instance of HashMap, the best way is:

fileParameters = new HashMap<String,String>();

Since Map is an interface, you need to pick some class that instantiates it if you want to create an empty instance. HashMap seems as good as any other - so just use that.

How to copy commits from one branch to another?

Here's another approach.

git checkout {SOURCE_BRANCH}               # switch to Source branch.
git checkout {COMMIT_HASH}                 # go back to the desired commit.
git checkout -b {temp_branch}              # create a new temporary branch from {COMMIT_HASH} snapshot.
git checkout {TARGET_BRANCH}               # switch to Target branch.
git merge {temp_branch}                    # merge code to your Target branch.
git branch -d {temp_branch}                # delete the temp branch.

Java2D: Increase the line width

You should use setStroke to set a stroke of the Graphics2D object.

The example at http://www.java2s.com gives you some code examples.

The following code produces the image below:

import java.awt.*;
import java.awt.geom.Line2D;
import javax.swing.*;

public class FrameTest {
    public static void main(String[] args) {
        JFrame jf = new JFrame("Demo");
        Container cp = jf.getContentPane();
        cp.add(new JComponent() {
            public void paintComponent(Graphics g) {
                Graphics2D g2 = (Graphics2D) g;
                g2.setStroke(new BasicStroke(10));
                g2.draw(new Line2D.Float(30, 20, 80, 90));
            }
        });
        jf.setSize(300, 200);
        jf.setVisible(true);
    }
}

enter image description here

(Note that the setStroke method is not available in the Graphics object. You have to cast it to a Graphics2D object.)


This post has been rewritten as an article here.

How to make button fill table cell

For starters:

<p align='center'>
<table width='100%'>
<tr>
<td align='center'><form><input type=submit value="click me" style="width:100%"></form></td>
</tr>
</table>
</p>

Note, if the width of the input button is 100%, you wont need the attribute "align='center'" anymore.

This would be the optimal solution:

<p align='center'>
<table width='100%'>
<tr>
<td><form><input type=submit value="click me" style="width:100%"></form></td>
</tr>
</table>
</p>

What is the Java equivalent for LINQ?

There is nothing like LINQ for Java.

...

Edit

Now with Java 8 we are introduced to the Stream API, this is a similar kind of thing when dealing with collections, but it is not quite the same as Linq.

If it is an ORM you are looking for, like Entity Framework, then you can try Hibernate

:-)

selenium - chromedriver executable needs to be in PATH

try this :

driver = webdriver.Chrome(ChromeDriverManager().install())

Save the console.log in Chrome to a file

Good news

Chrome dev tools now allows you to save the console output to a file natively

  1. Open the console
  2. Right-click
  3. Select "save as.."

save console to file

Chrome Developer instructions here.

What is the "-->" operator in C/C++?

while( x-- > 0 )

is how that's parsed.

adding onclick event to dynamically added button?

Remove the () from your expressions that are not working will get the desired results you need.

but.setAttribute("onclick",callJavascriptFunction);
but.onclick= callJavascriptFunction;
document.getElementById("but").onclick=callJavascriptFunction;

count number of characters in nvarchar column

I had a similar problem recently, and here's what I did:

    SELECT
         columnname as 'Original_Value',
         LEN(LTRIM(columnname)) as 'Orig_Val_Char_Count',
         N'['+columnname+']' as 'UnicodeStr_Value',
         LEN(N'['+columnname+']')-2 as 'True_Char_Count'
    FROM mytable 

The first two columns look at the original value and count the characters (minus leading/trailing spaces).

I needed to compare that with the true count of characters, which is why I used the second LEN function. It sets the column value to a string, forces that string to Unicode, and then counts the characters.

By using the brackets, you ensure that any leading or trailing spaces are also counted as characters; of course, you don't want to count the brackets themselves, so you subtract 2 at the end.

Updating a java map entry

If key is present table.put(key, val) will just overwrite the value else it'll create a new entry. Poof! and you are done. :)

you can get the value from a map by using key is table.get(key); That's about it

How can I create a product key for my C# application?

Whether it's trivial or hard to crack, I'm not sure that it really makes much of a difference.

The likelihood of your app being cracked is far more proportional to its usefulness rather than the strength of the product key handling.

Personally, I think there are two classes of user. Those who pay. Those who don't. The ones that do will likely do so with even the most trivial protection. Those who don't will wait for a crack or look elsewhere. Either way, it won't get you any more money.

Unexpected end of file error

You did forget to include stdafx.h in your source (as I cannot see it your code). If you didn't, then make sure #include "stdafx.h" is the first line in your .cpp file, otherwise you will see the same error even if you've included "stdafx.h" in your source file (but not in the very beginning of the file).

How do you round a number to two decimal places in C#?

  public double RoundDown(double number, int decimalPlaces)
        {
            return Math.Floor(number * Math.Pow(10, decimalPlaces)) / Math.Pow(10, decimalPlaces);
        }

How to access command line arguments of the caller inside a function?

You can use the shift keyword (operator?) to iterate through them. Example:

#!/bin/bash
function print()
{
    while [ $# -gt 0 ]
    do
        echo $1;
        shift 1;
    done
}
print $*;

Autowiring fails: Not an managed Type

For me the error was quite simple based on what @alfred_m said..... tomcat had 2 jars conflicting having same set of Class names and configuration.

What happened was ..............I copied my existing project to make a new project out of the existing project. but without making required changes, I started working on other project. Henec 2 projects had same classes and configuration files, resulting into conflict.

Deleted the copied project and things started working!!!!

Getting URL parameter in java and extract a specific text from that URL

this will work for all sort of youtube url :
if url could be

youtube.com/?v=_RCIP6OrQrE
youtube.com/v/_RCIP6OrQrE
youtube.com/watch?v=_RCIP6OrQrE
youtube.com/watch?v=_RCIP6OrQrE&feature=whatever&this=that

Pattern p = Pattern.compile("http.*\\?v=([a-zA-Z0-9_\\-]+)(?:&.)*");
String url = "http://www.youtube.com/watch?v=_RCIP6OrQrE";
Matcher m = p.matcher(url.trim()); //trim to remove leading and trailing space if any

if (m.matches()) {
    url = m.group(1);        
}
System.out.println(url);

this will extract video id from your url

further reference

How do I compare version numbers in Python?

... and getting back to easy ... for simple scripts you can use:

import sys
needs = (3, 9) # or whatever
pvi = sys.version_info.major, sys.version_info.minor    

later in your code

try:
    assert pvi >= needs
except:
    print("will fail!")
    # etc.

No visible cause for "Unexpected token ILLEGAL"

I changed all space areas to &nbsp, just like that and it worked without problem.

val.replace(" ", "&nbsp");

I hope it helps someone.

Python date string to date object

There is another library called arrow really great to make manipulation on python date.

import arrow
import datetime

a = arrow.get('24052010', 'DMYYYY').date()
print(isinstance(a, datetime.date)) # True

What is a good Hash Function?

For doing "normal" hash table lookups on basically any kind of data - this one by Paul Hsieh is the best I've ever used.

http://www.azillionmonkeys.com/qed/hash.html

If you care about cryptographically secure or anything else more advanced, then YMMV. If you just want a kick ass general purpose hash function for a hash table lookup, then this is what you're looking for.

How to clear Flutter's Build cache?

I tried flutter clean and that didn't work for me. Then I went to wipe the emulator's data and voila, the cached issue was gone. If you have Android Studio you can launch the AVD Manager by following this Create and Manage virtual machine. Otherwise you can wipe the emulator's data using the emulator.exe command line that's included in the android SDK. Simply follow this instructions here Start the emulator from the command line.

AlertDialog styling - how to change style (color) of title, message, etc

You need to define a Theme for your AlertDialog and reference it in your Activity's theme. The attribute is alertDialogTheme and not alertDialogStyle. Like this:

<style name="Theme.YourTheme" parent="@android:style/Theme.Holo">
    ...
    <item name="android:alertDialogTheme">@style/YourAlertDialogTheme</item>
</style>

<style name="YourAlertDialogTheme">
    <item name="android:windowBackground">@android:color/transparent</item>
    <item name="android:windowContentOverlay">@null</item>
    <item name="android:windowIsFloating">true</item>
    <item name="android:windowAnimationStyle">@android:style/Animation.Dialog</item>
    <item name="android:windowMinWidthMajor">@android:dimen/dialog_min_width_major</item>
    <item name="android:windowMinWidthMinor">@android:dimen/dialog_min_width_minor</item>
    <item name="android:windowTitleStyle">...</item>
    <item name="android:textAppearanceMedium">...</item>
    <item name="android:borderlessButtonStyle">...</item>
    <item name="android:buttonBarStyle">...</item>
</style>

You'll be able to change color and text appearance for the title, the message and you'll have some control on the background of each area. I wrote a blog post detailing the steps to style an AlertDialog.

SessionNotCreatedException: Message: session not created: This version of ChromeDriver only supports Chrome version 81

  1. First of all check latest Chrome version (This is your browser Chrome version) link

  2. Download same version of Chrome Web Driver from this link

Do not download latest Chrome Web Driver if it does not match your Chrome Browser version.

Note: When I write this message, latest Chrome Browser version is 84 but latest Chrome Driver version is 85. I am using Chrome Driver version 84 so that Chrome Driver and Chrome Browser versions are the same.

Proper way to empty a C-String

Depends on what you mean by emptying. If you just want an empty string, you could do

buffer[0] = 0;

If you want to set every element to zero, do

memset(buffer, 0, 80);

Update records in table from CTE

You don't need a CTE for this

UPDATE PEDI_InvoiceDetail
SET
    DocTotal = v.DocTotal
FROM
     PEDI_InvoiceDetail
inner join 
(
   SELECT InvoiceNumber, SUM(Sale + VAT) AS DocTotal
   FROM PEDI_InvoiceDetail
   GROUP BY InvoiceNumber
) v
   ON PEDI_InvoiceDetail.InvoiceNumber = v.InvoiceNumber

How to install latest version of git on CentOS 7.x/6.x

To build and install modern Git on CentOS 6:

yum install -y curl-devel expat-devel gettext-devel openssl-devel zlib-devel gcc perl-ExtUtils-MakeMaker
export GIT_VERSION=2.6.4
mkdir /root/git
cd /root/git
wget "https://www.kernel.org/pub/software/scm/git/git-${GIT_VERSION}.tar.gz"
tar xvzf "git-${GIT_VERSION}.tar.gz"
cd git-${GIT_VERSION}
make prefix=/usr/local all
make prefix=/usr/local install
yum remove -y git
git --version # should be GIT_VERSION

How do I clear inner HTML

The problem appears to be that the global symbol clear is already in use and your function doesn't succeed in overriding it. If you change that name to something else (I used blah), it works just fine:

Live: Version using clear which fails | Version using blah which works

<html>
<head>
    <title>lala</title>
</head>
<body>
    <h1 onmouseover="go('The dog is in its shed')" onmouseout="blah()">lalala</h1>
    <div id="goy"></div>
    <script type="text/javascript">
    function go(what) {
        document.getElementById("goy").innerHTML = what;
    }
    function blah() {
        document.getElementById("goy").innerHTML = "";
    }
    </script>
</body>
</html>

This is a great illustration of the fundamental principal: Avoid global variables wherever possible. The global namespace in browsers is incredibly crowded, and when conflicts occur, you get weird bugs like this.

A corollary to that is to not use old-style onxyz=... attributes to hook up event handlers, because they require globals. Instead, at least use code to hook things up: Live Copy

<html>
<head>
    <title>lala</title>
</head>
<body>
    <h1 id="the-header">lalala</h1>
    <div id="goy"></div>
    <script type="text/javascript">
      // Scoping function makes the declarations within
      // it *not* globals
      (function(){
        var header = document.getElementById("the-header");
        header.onmouseover = function() {
          go('The dog is in its shed');
        };
        header.onmouseout = clear;

        function go(what) {
          document.getElementById("goy").innerHTML = what;
        }
        function clear() {
          document.getElementById("goy").innerHTML = "";
        }
      })();
    </script>
</body>
</html>

...and even better, use DOM2's addEventListener (or attachEvent on IE8 and earlier) so you can have multiple handlers for an event on an element.

Is there a performance difference between CTE , Sub-Query, Temporary Table or Table Variable?

Just 2 things I think make it ALWAYS preferable to use a # Temp Table rather then a CTE are:

  1. You can not put a primary key on a CTE so the data being accessed by the CTE will have to traverse each one of the indexes in the CTE's tables rather then just accessing the PK or Index on the temp table.

  2. Because you can not add constraints, indexes and primary keys to a CTE they are more prone to bugs creeping in and bad data.


-onedaywhen yesterday

Here is an example where #table constraints can prevent bad data which is not the case in CTE's

DECLARE @BadData TABLE ( 
                       ThisID int
                     , ThatID int );
INSERT INTO @BadData
       ( ThisID
       , ThatID
       ) 
VALUES
       ( 1, 1 ),
       ( 1, 2 ),
       ( 2, 2 ),
       ( 1, 1 );

IF OBJECT_ID('tempdb..#This') IS NOT NULL
    DROP TABLE #This;
CREATE TABLE #This ( 
             ThisID int NOT NULL
           , ThatID int NOT NULL
                        UNIQUE(ThisID, ThatID) );
INSERT INTO #This
SELECT * FROM @BadData;
WITH This_CTE
     AS (SELECT *
           FROM @BadData)
     SELECT *
       FROM This_CTE;

Is it .yaml or .yml?

EDIT:

So which am I supposed to use? The proper 4 letter extension suggested by the creator, or the 3 letter extension found in the wild west of the internet?

This question could be:

  1. A request for advice; or

  2. A natural expression of that particular emotion which is experienced, while one is observing that some official recommendation is being disregarded—prominently, or even predominantly.

People differ in their predilection for following:

  1. Official advice; or

  2. The preponderance of practice.

Of course, I am unlikely to influence you, regarding which of these two paths you prefer to take!

In what follows (and, in the spirit of science), I merely make an hypothesis, about what (merely as a matter of fact) led the majority of people to use the 3-letter extension. And, I focus on efficient causes.

By this, I do not intend moral exhortation. As you may recall, the fact that something is, does not imply that it should be.

Whatever your personal inclination, be it to follow one path or the other, I do not object.

(End of edit.)

The suggestion, that this preference (in real life usage) was caused by a 8.3 character DOS-ish limitation, IMO is a red herring (erroneous and misleading).

As of August, 2016, the Google search counts for YML and YAML were approximately 6,000,000 and 4,100,000 (to two digits of precision). Furthermore, the "YAML" count was unfairly high because it included mention of the language by name, beyond its use as an extension.

As of July, 2018, the Google's search counts for YML and YAML were approximately 8,100,000 and 4,100,000 (again, to two digits of precision). So, in the last two years, YML has essentially doubled in popularity, but YAML has stayed the same.

Another cultural measure is websites which attempt to explain file extensions. For example, on the FilExt website (as of July, 2018), the page for YAML results in: "Ooops! The FILEXT.com database does not have any information on file extension .YAML."

Whereas, it has an entry for YML, which gives: "YAML...uses a text file and organizes it into a format which is Human-readable. 'database.yml' is a typical example when YAML is used by Ruby on Rails to connect to a database."

As of November, 2014, Wikipedia's article on extension YML still stated that ".yml" is "the file extension for the YAML file format" (emphasis added). Its YAML article lists both extensions, without expressing a preference.

The extension ".yml" is sufficiently clear, is more brief (thus easier to type and recognize), and is much more common.

Of course, both of these extensions could be viewed as abbreviations of a long, possible extension, ".yamlaintmarkuplanguage". But programmers (and users) don't want to type all of that!

Instead, we programmers (and users) want to type as little as possible, and still yet be unambiguous and clear. And we want to see what kind of file it is, as quickly as possible, without reading a longer word. Typing just how many characters accomplishes both of these goals? Isn't the answer three (3)? In other words, YML?

Wikipedia's Category:Filename_extensions page lists entries for .a, .o and .Z. Somehow, it missed .c and .h (used by the C language). These example single-letter extensions help us to see that extensions should be as long as necessary, but no longer (to half-quote Albert Einstein).

Instead, notice that, in general, few extensions start with "Y". Commonly, on the other hand, the letter X is used for a great variety of meanings including "cross," "extensible," "extreme," "variable," etc. (e.g. in XML). So starting with "Y" already conveys much information (in terms of information theory), whereas starting with "X" does not.

Linguistically speaking, therefore, the acronym "XML" has (in a way) only two informative letters ("M" and "L"). "YML", instead, has three informative letters ("M", "L" and "Y"). Indeed, the existing set of acronyms beginning with Y seems extremely small. By implication, this is why a four letter YAML file extension feels greatly overspecified.

Perhaps this is why we see in practice that the "linguistic" pressure (in natural use) to lengthen the abbreviation in question to four (4) characters is weak, and the "linguistic" pressure to shorten this abbreviation to three (3) characters is strong.

Purely as a result, probably, of these factors (and not as an official endorsement), I would note that the YAML.org website's latest news item (from November, 2011) is all about a project written in JavaScript, JS-YAML, which, itself, internally prefers to use the extension ".yml".

The above-mentioned factors may have been the main ones; nevertheless, all the factors (known or unknown) have resulted in the abbreviated, three (3) character extension becoming the one in predominant use for YAML—despite the inventors' preference.

".YML" seems to be the de facto standard. Yet the same inventors were perceptive and correct, about the world's need for a human-readable data language. And we should thank them for providing it.

What can MATLAB do that R cannot do?

We can't because it's expected/required by our customers.

"com.jcraft.jsch.JSchException: Auth fail" with working passwords

Try to add auth method explicitly as below, because sometimes it is required:

session.setConfig("PreferredAuthentications", "password");

recursively use scp but excluding some folders

If you use a pem file to authenticate u can use the following command (which will exclude files with something extension):

rsync -Lavz -e "ssh -i <full-path-to-pem> -o StrictHostKeyChecking=no -o UserKnownHostsFile=/dev/null" --exclude "*.something" --progress <path inside local host> <user>@<host>:<path inside remote host>

The -L means follow links (copy files not links). Use full path to your pem file and not relative.

Using sshfs is not recommended since it works slowly. Also, the combination of find and scp that was presented above is also a bad idea since it will open a ssh session per file which is too expensive.

Open a new tab on button click in AngularJS

Proper HTML way: just surround your button with anchor element and add attribute target="_blank". It is as simple as that:

<a ng-href="{{yourDynamicURL}}" target="_blank">
    <h1>Open me in new Tab</h1>
</a>

where you can set in the controller:

$scope.yourDynamicURL = 'https://stackoverflow.com';

How to validate phone number in laravel 5.2?

There are a lot of things to consider when validating a phone number if you really think about it. (especially international) so using a package is better than the accepted answer by far, and if you want something simple like a regex I would suggest using something better than what @SlateEntropy suggested. (something like A comprehensive regex for phone number validation)

Seaborn Barplot - Displaying Values

Works with single ax or with matrix of ax (subplots)

from matplotlib import pyplot as plt
import numpy as np

def show_values_on_bars(axs):
    def _show_on_single_plot(ax):        
        for p in ax.patches:
            _x = p.get_x() + p.get_width() / 2
            _y = p.get_y() + p.get_height()
            value = '{:.2f}'.format(p.get_height())
            ax.text(_x, _y, value, ha="center") 

    if isinstance(axs, np.ndarray):
        for idx, ax in np.ndenumerate(axs):
            _show_on_single_plot(ax)
    else:
        _show_on_single_plot(axs)

fig, ax = plt.subplots(1, 2)
show_values_on_bars(ax)

How to create a new file in unix?

Try > workdirectory/filename.txt

This would:

  • truncate the file if it exists
  • create if it doesn't exist

You can consider it equivalent to:

rm -f workdirectory/filename.txt; touch workdirectory/filename.txt

sklearn plot confusion matrix with labels

I found a function that can plot the confusion matrix which generated from sklearn.

import numpy as np


def plot_confusion_matrix(cm,
                          target_names,
                          title='Confusion matrix',
                          cmap=None,
                          normalize=True):
    """
    given a sklearn confusion matrix (cm), make a nice plot

    Arguments
    ---------
    cm:           confusion matrix from sklearn.metrics.confusion_matrix

    target_names: given classification classes such as [0, 1, 2]
                  the class names, for example: ['high', 'medium', 'low']

    title:        the text to display at the top of the matrix

    cmap:         the gradient of the values displayed from matplotlib.pyplot.cm
                  see http://matplotlib.org/examples/color/colormaps_reference.html
                  plt.get_cmap('jet') or plt.cm.Blues

    normalize:    If False, plot the raw numbers
                  If True, plot the proportions

    Usage
    -----
    plot_confusion_matrix(cm           = cm,                  # confusion matrix created by
                                                              # sklearn.metrics.confusion_matrix
                          normalize    = True,                # show proportions
                          target_names = y_labels_vals,       # list of names of the classes
                          title        = best_estimator_name) # title of graph

    Citiation
    ---------
    http://scikit-learn.org/stable/auto_examples/model_selection/plot_confusion_matrix.html

    """
    import matplotlib.pyplot as plt
    import numpy as np
    import itertools

    accuracy = np.trace(cm) / np.sum(cm).astype('float')
    misclass = 1 - accuracy

    if cmap is None:
        cmap = plt.get_cmap('Blues')

    plt.figure(figsize=(8, 6))
    plt.imshow(cm, interpolation='nearest', cmap=cmap)
    plt.title(title)
    plt.colorbar()

    if target_names is not None:
        tick_marks = np.arange(len(target_names))
        plt.xticks(tick_marks, target_names, rotation=45)
        plt.yticks(tick_marks, target_names)

    if normalize:
        cm = cm.astype('float') / cm.sum(axis=1)[:, np.newaxis]


    thresh = cm.max() / 1.5 if normalize else cm.max() / 2
    for i, j in itertools.product(range(cm.shape[0]), range(cm.shape[1])):
        if normalize:
            plt.text(j, i, "{:0.4f}".format(cm[i, j]),
                     horizontalalignment="center",
                     color="white" if cm[i, j] > thresh else "black")
        else:
            plt.text(j, i, "{:,}".format(cm[i, j]),
                     horizontalalignment="center",
                     color="white" if cm[i, j] > thresh else "black")


    plt.tight_layout()
    plt.ylabel('True label')
    plt.xlabel('Predicted label\naccuracy={:0.4f}; misclass={:0.4f}'.format(accuracy, misclass))
    plt.show()

It will look like this enter image description here

Run Excel Macro from Outside Excel Using VBScript From Command Line

If you are trying to run the macro from your personal workbook it might not work as opening an Excel file with a VBScript doesnt automatically open your PERSONAL.XLSB. you will need to do something like this:

Dim oFSO
Dim oShell, oExcel, oFile, oSheet
Set oFSO = CreateObject("Scripting.FileSystemObject")
Set oShell = CreateObject("WScript.Shell")
Set oExcel = CreateObject("Excel.Application")
Set wb2 = oExcel.Workbooks.Open("C:\..\PERSONAL.XLSB") 'Specify foldername here

oExcel.DisplayAlerts = False


For Each oFile In oFSO.GetFolder("C:\Location\").Files
    If LCase(oFSO.GetExtensionName(oFile)) = "xlsx" Then
        With oExcel.Workbooks.Open(oFile, 0, True, , , , True, , , , False, , False)



            oExcel.Run wb2.Name & "!modForm"


            For Each oSheet In .Worksheets



                oSheet.SaveAs "C:\test\" & oFile.Name & "." & oSheet.Name & ".txt", 6


            Next
            .Close False, , False
        End With
    End If



Next
oExcel.Quit
oShell.Popup "Conversion complete", 10

So at the beginning of the loop it is opening personals.xlsb and running the macro from there for all the other workbooks. Just thought I should post in here just in case someone runs across this like I did but cant figure out why the macro is still not running.

Assembly - JG/JNLE/JL/JNGE after CMP

When you do a cmp a,b, the flags are set as if you had calculated a - b.

Then the jmp-type instructions check those flags to see if the jump should be made.

In other words, the first block of code you have (with my comments added):

cmp al,dl     ; set flags based on the comparison
jg label1     ; then jump based on the flags

would jump to label1 if and only if al was greater than dl.

You're probably better off thinking of it as al > dl but the two choices you have there are mathematically equivalent:

al > dl
al - dl > dl - dl (subtract dl from both sides)
al - dl > 0       (cancel the terms on the right hand side)

You need to be careful when using jg inasmuch as it assumes your values were signed. So, if you compare the bytes 101 (101 in two's complement) with 200 (-56 in two's complement), the former will actually be greater. If that's not what was desired, you should use the equivalent unsigned comparison.

See here for more detail on jump selection, reproduced below for completeness. First the ones where signed-ness is not appropriate:

+--------+------------------------------+-------------+--------------------+
|Instr   | Description                  | signed-ness | Flags              |
+--------+------------------------------+-------------+--------------------+
| JO     | Jump if overflow             |             | OF = 1             |
+--------+------------------------------+-------------+--------------------+
| JNO    | Jump if not overflow         |             | OF = 0             |
+--------+------------------------------+-------------+--------------------+
| JS     | Jump if sign                 |             | SF = 1             |
+--------+------------------------------+-------------+--------------------+
| JNS    | Jump if not sign             |             | SF = 0             |
+--------+------------------------------+-------------+--------------------+
| JE/    | Jump if equal                |             | ZF = 1             |
| JZ     | Jump if zero                 |             |                    |
+--------+------------------------------+-------------+--------------------+
| JNE/   | Jump if not equal            |             | ZF = 0             |
| JNZ    | Jump if not zero             |             |                    |
+--------+------------------------------+-------------+--------------------+
| JP/    | Jump if parity               |             | PF = 1             |
| JPE    | Jump if parity even          |             |                    |
+--------+------------------------------+-------------+--------------------+
| JNP/   | Jump if no parity            |             | PF = 0             |
| JPO    | Jump if parity odd           |             |                    |
+--------+------------------------------+-------------+--------------------+
| JCXZ/  | Jump if CX is zero           |             | CX = 0             |
| JECXZ  | Jump if ECX is zero          |             | ECX = 0            |
+--------+------------------------------+-------------+--------------------+

Then the unsigned ones:

+--------+------------------------------+-------------+--------------------+
|Instr   | Description                  | signed-ness | Flags              |
+--------+------------------------------+-------------+--------------------+
| JB/    | Jump if below                | unsigned    | CF = 1             |
| JNAE/  | Jump if not above or equal   |             |                    |
| JC     | Jump if carry                |             |                    |
+--------+------------------------------+-------------+--------------------+
| JNB/   | Jump if not below            | unsigned    | CF = 0             |
| JAE/   | Jump if above or equal       |             |                    |
| JNC    | Jump if not carry            |             |                    |
+--------+------------------------------+-------------+--------------------+
| JBE/   | Jump if below or equal       | unsigned    | CF = 1 or ZF = 1   |
| JNA    | Jump if not above            |             |                    |
+--------+------------------------------+-------------+--------------------+
| JA/    | Jump if above                | unsigned    | CF = 0 and ZF = 0  |
| JNBE   | Jump if not below or equal   |             |                    |
+--------+------------------------------+-------------+--------------------+

And, finally, the signed ones:

+--------+------------------------------+-------------+--------------------+
|Instr   | Description                  | signed-ness | Flags              |
+--------+------------------------------+-------------+--------------------+
| JL/    | Jump if less                 | signed      | SF <> OF           |
| JNGE   | Jump if not greater or equal |             |                    |
+--------+------------------------------+-------------+--------------------+
| JGE/   | Jump if greater or equal     | signed      | SF = OF            |
| JNL    | Jump if not less             |             |                    |
+--------+------------------------------+-------------+--------------------+
| JLE/   | Jump if less or equal        | signed      | ZF = 1 or SF <> OF |
| JNG    | Jump if not greater          |             |                    |
+--------+------------------------------+-------------+--------------------+
| JG/    | Jump if greater              | signed      | ZF = 0 and SF = OF |
| JNLE   | Jump if not less or equal    |             |                    |
+--------+------------------------------+-------------+--------------------+

What is the best collation to use for MySQL with PHP?

It is best to use character set utf8mb4 with the collation utf8mb4_unicode_ci.

The character set, utf8, only supports a small amount of UTF-8 code points, about 6% of possible characters. utf8 only supports the Basic Multilingual Plane (BMP). There 16 other planes. Each plane contains 65,536 characters. utf8mb4 supports all 17 planes.

MySQL will truncate 4 byte UTF-8 characters resulting in corrupted data.

The utf8mb4 character set was introduced in MySQL 5.5.3 on 2010-03-24.

Some of the required changes to use the new character set are not trivial:

  • Changes may need to be made in your application database adapter.
  • Changes will need to be made to my.cnf, including setting the character set, the collation and switching innodb_file_format to Barracuda
  • SQL CREATE statements may need to include: ROW_FORMAT=DYNAMIC
    • DYNAMIC is required for indexes on VARCHAR(192) and larger.

NOTE: Switching to Barracuda from Antelope, may require restarting the MySQL service more than once. innodb_file_format_max does not change until after the MySQL service has been restarted to: innodb_file_format = barracuda.

MySQL uses the old Antelope InnoDB file format. Barracuda supports dynamic row formats, which you will need if you do not want to hit the SQL errors for creating indexes and keys after you switch to the charset: utf8mb4

  • #1709 - Index column size too large. The maximum column size is 767 bytes.
  • #1071 - Specified key was too long; max key length is 767 bytes

The following scenario has been tested on MySQL 5.6.17: By default, MySQL is configured like this:

SHOW VARIABLES;

innodb_large_prefix = OFF
innodb_file_format = Antelope

Stop your MySQL service and add the options to your existing my.cnf:

[client]
default-character-set= utf8mb4

[mysqld]
explicit_defaults_for_timestamp = true
innodb_large_prefix = true
innodb_file_format = barracuda
innodb_file_format_max = barracuda
innodb_file_per_table = true

# Character collation
character_set_server=utf8mb4
collation_server=utf8mb4_unicode_ci

Example SQL CREATE statement:

CREATE TABLE Contacts (
 id INT AUTO_INCREMENT NOT NULL,
 ownerId INT DEFAULT NULL,
 created timestamp NOT NULL DEFAULT '0000-00-00 00:00:00',
 modified timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
 contact VARCHAR(640) NOT NULL,
 prefix VARCHAR(128) NOT NULL,
 first VARCHAR(128) NOT NULL,
 middle VARCHAR(128) NOT NULL,
 last VARCHAR(128) NOT NULL,
 suffix VARCHAR(128) NOT NULL,
 notes MEDIUMTEXT NOT NULL,
 INDEX IDX_CA367725E05EFD25 (ownerId),
 INDEX created (created),
 INDEX modified_idx (modified),
 INDEX contact_idx (contact),
 PRIMARY KEY(id)
) DEFAULT CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci ENGINE = InnoDB ROW_FORMAT=DYNAMIC;
  • You can see error #1709 generated for INDEX contact_idx (contact) if ROW_FORMAT=DYNAMIC is removed from the CREATE statement.

NOTE: Changing the index to limit to the first 128 characters on contacteliminates the requirement for using Barracuda with ROW_FORMAT=DYNAMIC

INDEX contact_idx (contact(128)),

Also note: when it says the size of the field is VARCHAR(128), that is not 128 bytes. You can use have 128, 4 byte characters or 128, 1 byte characters.

This INSERT statement should contain the 4 byte 'poo' character in the 2 row:

INSERT INTO `Contacts` (`id`, `ownerId`, `created`, `modified`, `contact`, `prefix`, `first`, `middle`, `last`, `suffix`, `notes`) VALUES
(1, NULL, '0000-00-00 00:00:00', '2014-08-25 03:00:36', '1234567890', '12345678901234567890', '1234567890123456789012345678901234567890', '1234567890123456789012345678901234567890', '12345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678', '', ''),
(2, NULL, '0000-00-00 00:00:00', '2014-08-25 03:05:57', 'poo', '12345678901234567890', '', '', '', '', ''),
(3, NULL, '0000-00-00 00:00:00', '2014-08-25 03:05:57', 'poo', '12345678901234567890', '', '', '123', '', '');

You can see the amount of space used by the last column:

mysql> SELECT BIT_LENGTH(`last`), CHAR_LENGTH(`last`) FROM `Contacts`;
+--------------------+---------------------+
| BIT_LENGTH(`last`) | CHAR_LENGTH(`last`) |
+--------------------+---------------------+
|               1024 |                 128 | -- All characters are ASCII
|               4096 |                 128 | -- All characters are 4 bytes
|               4024 |                 128 | -- 3 characters are ASCII, 125 are 4 bytes
+--------------------+---------------------+

In your database adapter, you may want to set the charset and collation for your connection:

SET NAMES 'utf8mb4' COLLATE 'utf8mb4_unicode_ci'

In PHP, this would be set for: \PDO::MYSQL_ATTR_INIT_COMMAND

References:

How to randomize Excel rows

Perhaps the whole column full of random numbers is not the best way to do it, but it seems like probably the most practical as @mariusnn mentioned.

On that note, this stomped me for a while with Office 2010, and while generally answers like the one in lifehacker work,I just wanted to share an extra step required for the numbers to be unique:

  1. Create a new column next to the list that you're going to randomize
  2. Type in =rand() in the first cell of the new column - this will generate a random number between 0 and 1
  3. Fill the column with that formula. The easiest way to do this may be to:

    • go down along the new column up until the last cell that you want to randomize
    • hold down Shift and click on the last cell
    • press Ctrl+D
  4. Now you should have a column of identical numbers, even though they are all generated randomly.

    Random numbers... that are the same...

    The trick here is to recalculate them! Go to the Formulas tab and then click on Calculate Now (or press F9).

    Actually random numbers!

    Now all the numbers in the column will be actually generated randomly.

  5. Go to the Home tab and click on Sort & Filter. Choose whichever order you want (Smallest to Largest or Largest to Smallest) - whichever one will give you a random order with respect to the original order. Then click OK when the Sort Warning prompts you to Expand the selection.

  6. Your list should be randomized now! You can get rid of the column of random numbers if you want.

Returning JSON response from Servlet to Javascript/JSP page

I used JSONObject as shown below in Servlet.

    JSONObject jsonReturn = new JSONObject();

    NhAdminTree = AdminTasks.GetNeighborhoodTreeForNhAdministrator( connection, bwcon, userName);

    map = new HashMap<String, String>();
    map.put("Status", "Success");
    map.put("FailureReason", "None");
    map.put("DataElements", "2");

    jsonReturn = new JSONObject();
    jsonReturn.accumulate("Header", map);

    List<String> list = new ArrayList<String>();
    list.add(NhAdminTree);
    list.add(userName);

    jsonReturn.accumulate("Elements", list);

The Servlet returns this JSON object as shown below:

    response.setContentType("application/json");
    response.getWriter().write(jsonReturn.toString());

This Servlet is called from Browser using AngularJs as below

$scope.GetNeighborhoodTreeUsingPost = function(){
    alert("Clicked GetNeighborhoodTreeUsingPost : " + $scope.userName );

    $http({

        method: 'POST',
        url : 'http://localhost:8080/EPortal/xlEPortalService',
        headers: {
           'Content-Type': 'application/json'
         },
        data : {
            'action': 64,
            'userName' : $scope.userName
        }
    }).success(function(data, status, headers, config){
        alert("DATA.header.status : " + data.Header.Status);
        alert("DATA.header.FailureReason : " + data.Header.FailureReason);
        alert("DATA.header.DataElements : " + data.Header.DataElements);
        alert("DATA.elements : " + data.Elements);

    }).error(function(data, status, headers, config) {
        alert(data + " : " + status + " : " + headers + " : " + config);
    });

};

This code worked and it is showing correct data in alert dialog box:

Data.header.status : Success

Data.header.FailureReason : None

Data.header.DetailElements : 2

Data.Elements : Coma seperated string values i.e. NhAdminTree, userName

Regex pattern for checking if a string starts with a certain substring?

I really recommend using the String.StartsWith method over the Regex.IsMatch if you only plan to check the beginning of a string.

  • Firstly, the regular expression in C# is a language in a language with does not help understanding and code maintenance. Regular expression is a kind of DSL.
  • Secondly, many developers does not understand regular expressions: it is something which is not understandable for many humans.
  • Thirdly, the StartsWith method brings you features to enable culture dependant comparison which regular expressions are not aware of.

In your case you should use regular expressions only if you plan implementing more complex string comparison in the future.

Copy files from one directory into an existing directory

Assuming t1 is the folder with files in it, and t2 is the empty directory. What you want is something like this:

sudo cp -R t1/* t2/

Bear in mind, for the first example, t1 and t2 have to be the full paths, or relative paths (based on where you are). If you want, you can navigate to the empty folder (t2) and do this:

sudo cp -R t1/* ./

Or you can navigate to the folder with files (t1) and do this:

sudo cp -R ./* t2/

Note: The * sign (or wildcard) stands for all files and folders. The -R flag means recursively (everything inside everything).

How To: Best way to draw table in console app (C#)

There're several open-source libraries which allow console table formatting, ranging from simple (like the code samples in the answers here) to more advanced.

ConsoleTable

Judging by NuGet stats, the most popular library for formatting tables is ConsoleTable. Tables are constructed like this (from the readme file):

var table = new ConsoleTable("one", "two", "three");
table.AddRow(1, 2, 3)
     .AddRow("this line should be longer", "yes it is", "oh");

Tables can be formatted using one of the predefined styles. It'll look like this:

--------------------------------------------------
| one                        | two       | three |
--------------------------------------------------
| 1                          | 2         | 3     |
--------------------------------------------------
| this line should be longer | yes it is | oh    |
--------------------------------------------------

This library expects single-line cells with no formatting.

There're a couple of libraries based on ConsoleTable with slightly extended feature sets, like more line styles.

CsConsoleFormat

If you need more complex formatting, you can use CsConsoleFormat.† Here's a table generated from a process list (from a sample project):

new Grid { Stroke = StrokeHeader, StrokeColor = DarkGray }
    .AddColumns(
        new Column { Width = GridLength.Auto },
        new Column { Width = GridLength.Auto, MaxWidth = 20 },
        new Column { Width = GridLength.Star(1) },
        new Column { Width = GridLength.Auto }
    )
    .AddChildren(
        new Cell { Stroke = StrokeHeader, Color = White }
            .AddChildren("Id"),
        new Cell { Stroke = StrokeHeader, Color = White }
            .AddChildren("Name"),
        new Cell { Stroke = StrokeHeader, Color = White }
            .AddChildren("Main Window Title"),
        new Cell { Stroke = StrokeHeader, Color = White }
            .AddChildren("Private Memory"),
        processes.Select(process => new[] {
            new Cell { Stroke = StrokeRight }
                .AddChildren(process.Id),
            new Cell { Stroke = StrokeRight, Color = Yellow, TextWrap = TextWrapping.NoWrap }
                .AddChildren(process.ProcessName),
            new Cell { Stroke = StrokeRight, Color = White, TextWrap = TextWrapping.NoWrap }
                .AddChildren(process.MainWindowTitle),
            new Cell { Stroke = LineThickness.None, Align = HorizontalAlignment.Right }
                .AddChildren(process.PrivateMemorySize64.ToString("n0")),
        })
    )

The end result will look like this:

It supports any kind of table lines (several included and customizable), multi-line cells with word wrap, colors, columns growing based on content or percentage, text alignment etc.

† CsConsoleFormat was developed by me.

How to config Tomcat to serve images from an external folder outside webapps?

You can deploy an images folder as a separate webapp and define the location of that folder to be anywhere in the file system.

Create a Context element in an XML file in the directory $CATALINA_HOME/conf/[enginename]/[hostname]/ where enginename might be 'Catalina' and hostname might be 'localhost'.

Name the file based on the path URL you want the images to be viewed from, so if your webapp has path 'blog', you might name the XML file blog#images.xml and so that your images would be visible at example.com/blog/images/

The content of the XML file should be <Context docBase="/filesystem/path/to/images"/>

Be careful not to undeploy this webapp, as that could delete all your images!

AngularJS : ng-model binding not updating when changed with jQuery

You have to trigger the change event of the input element because ng-model listens to input events and the scope will be updated. However, the regular jQuery trigger didn't work for me. But here is what works like a charm

$("#myInput")[0].dispatchEvent(new Event("input", { bubbles: true })); //Works

Following didn't work

$("#myInput").trigger("change"); // Did't work for me

You can read more about creating and dispatching synthetic events.

Allow Google Chrome to use XMLHttpRequest to load a URL from a local file

Mac version. From terminal run:

open /Applications/Google\ Chrome.app/ --args --allow-file-access-from-files

MySQL maximum memory usage

We use these settings:

etc/my.cnf
innodb_buffer_pool_size = 384M
key_buffer = 256M
query_cache_size = 1M
query_cache_limit = 128M
thread_cache_size = 8
max_connections = 400
innodb_lock_wait_timeout = 100

for a server with the following specifications:

Dell Server
CPU cores: Two
Processor(s): 1x Dual Xeon
Clock Speed: >= 2.33GHz
RAM: 2 GBytes
Disks: 1×250 GB SATA

Split long commands in multiple lines through Windows batch file

You can break up long lines with the caret ^ as long as you remember that the caret and the newline following it are completely removed. So, if there should be a space where you're breaking the line, include a space. (More on that below.)

Example:

copy file1.txt file2.txt

would be written as:

copy file1.txt^
 file2.txt

Cannot stop or restart a docker container

All the docker: start | restart | stop | rm --force | kill commands may not work if the container is stuck. You can always restart the docker daemon. However, if you have other containers running, that may not be the option. What you can do is:

ps aux | grep <<container id>> | awk '{print $1 $2}'

The output contains:

<<user>><<process id>>

Then kill the process associated with the container like so:

sudo kill -9 <<process id from above command>>

That will kill the container and you can start a new container with the right image.

Read Content from Files which are inside Zip file

Because of the condition in while, the loop might never break:

while (entry != null) {
  // If entry never becomes null here, loop will never break.
}

Instead of the null check there, you can try this:

ZipEntry entry = null;
while ((entry = zip.getNextEntry()) != null) {
  // Rest of your code
}

"Object doesn't support this property or method" error in IE11

This unfortunately breaks other things. Here is the fix I found on another site that seemed to work for me:

I'd say leave the X-UA-Compatible as "IE=8" and add the following code to the bottom of your master page:

<script language="javascript">
    /* IE11 Fix for SP2010 */
    if (typeof(UserAgentInfo) != 'undefined' && !window.addEventListener) 
    {
        UserAgentInfo.strBrowser=1; 
    } 
</script>

This fixes a bug in core.js which incorrectly calculates that sets UserAgentInfo.strBrowse=3 for IE11 and thus supporting addEventListener. I'm not entirely sure on the details other than that but the combination of keeping IE=8 and using this script is working for me. Fingers crossed until I find the next IE11/SharePoint "bug"!

Setting initial values on load with Select2 with Ajax

The function which you are specifying as initSelection is called with the initial value as argument. So if value is empty, the function is not called.
When you specifiy value='[{"id":"IN","name":"India"}]' instead of data-initvalue the function gets called and the selection can get initialized.

Differences between Html.TextboxFor and Html.EditorFor in MVC and Razor

The Html.TextboxFor always creates a textbox (<input type="text" ...).

While the EditorFor looks at the type and meta information, and can render another control or a template you supply.

For example for DateTime properties you can create a template that uses the jQuery DatePicker.

Clear text from textarea with selenium

It is general syntax

driver.find_element_by_id('Locator value').clear();
driver.find_element_by_name('Locator value').clear();

HTML5 form required attribute. Set custom validation message?

Use setCustomValidity:

document.addEventListener("DOMContentLoaded", function() {
    var elements = document.getElementsByTagName("INPUT");
    for (var i = 0; i < elements.length; i++) {
        elements[i].oninvalid = function(e) {
            e.target.setCustomValidity("");
            if (!e.target.validity.valid) {
                e.target.setCustomValidity("This field cannot be left blank");
            }
        };
        elements[i].oninput = function(e) {
            e.target.setCustomValidity("");
        };
    }
})

I changed to vanilla JavaScript from Mootools as suggested by @itpastorn in the comments, but you should be able to work out the Mootools equivalent if necessary.

Edit

I've updated the code here as setCustomValidity works slightly differently to what I understood when I originally answered. If setCustomValidity is set to anything other than the empty string it will cause the field to be considered invalid; therefore you must clear it before testing validity, you can't just set it and forget.

Further edit

As pointed out in @thomasvdb's comment below, you need to clear the custom validity in some event outside of invalid otherwise there may be an extra pass through the oninvalid handler to clear it.

Convert bytes to int?

Assuming you're on at least 3.2, there's a built in for this:

int.from_bytes( bytes, byteorder, *, signed=False )

...

The argument bytes must either be a bytes-like object or an iterable producing bytes.

The byteorder argument determines the byte order used to represent the integer. If byteorder is "big", the most significant byte is at the beginning of the byte array. If byteorder is "little", the most significant byte is at the end of the byte array. To request the native byte order of the host system, use sys.byteorder as the byte order value.

The signed argument indicates whether two’s complement is used to represent the integer.


## Examples:
int.from_bytes(b'\x00\x01', "big")                         # 1
int.from_bytes(b'\x00\x01', "little")                      # 256

int.from_bytes(b'\x00\x10', byteorder='little')            # 4096
int.from_bytes(b'\xfc\x00', byteorder='big', signed=True)  #-1024

Check if a number has a decimal place/is a whole number

function isDecimal(n){
    if(n == "")
        return false;

    var strCheck = "0123456789";
    var i;

    for(i in n){
        if(strCheck.indexOf(n[i]) == -1)
            return false;
    }
    return true;
}

How to skip the OPTIONS preflight request?

I think best way is check if request is of type "OPTIONS" return 200 from middle ware. It worked for me.

express.use('*',(req,res,next) =>{
      if (req.method == "OPTIONS") {
        res.status(200);
        res.send();
      }else{
        next();
      }
    });

Value Change Listener to JTextField

If we use runnable method SwingUtilities.invokeLater() while using Document listener application is getting stuck sometimes and taking time to update the result(As per my experiment). Instead of that we can also use KeyReleased event for text field change listener as mentioned here.

usernameTextField.addKeyListener(new KeyAdapter() {
    public void keyReleased(KeyEvent e) {
        JTextField textField = (JTextField) e.getSource();
        String text = textField.getText();
        textField.setText(text.toUpperCase());
    }
});

Using group by and having clause

The semantics of Having

To better understand having, you need to see it from a theoretical point of view.

A group by is a query that takes a table and summarizes it into another table. You summarize the original table by grouping the original table into subsets (based upon the attributes that you specify in the group by). Each of these groups will yield one tuple.

The Having is simply equivalent to a WHERE clause after the group by has executed and before the select part of the query is computed.

Lets say your query is:

select a, b, count(*) 
from Table 
where c > 100 
group by a, b 
having count(*) > 10;

The evaluation of this query can be seen as the following steps:

  1. Perform the WHERE, eliminating rows that do not satisfy it.
  2. Group the table into subsets based upon the values of a and b (each tuple in each subset has the same values of a and b).
  3. Eliminate subsets that do not satisfy the HAVING condition
  4. Process each subset outputting the values as indicated in the SELECT part of the query. This creates one output tuple per subset left after step 3.

You can extend this to any complex query there Table can be any complex query that return a table (a cross product, a join, a UNION, etc).

In fact, having is syntactic sugar and does not extend the power of SQL. Any given query:

SELECT list 
FROM table
GROUP BY attrList
HAVING condition;

can be rewritten as:

SELECT list from (
   SELECT listatt 
   FROM table 
   GROUP BY attrList) as Name
WHERE condition;

The listatt is a list that includes the GROUP BY attributes and the expressions used in list and condition. It might be necessary to name some expressions in this list (with AS). For instance, the example query above can be rewritten as:

select a, b, count 
from (select a, b, count(*) as count
      from Table 
      where c > 100
      group by a, b) as someName
where count > 10;

The solution you need

Your solution seems to be correct:

SELECT s.sid, s.name
FROM Supplier s, Supplies su, Project pr
WHERE s.sid = su.sid AND su.jid = pr.jid
GROUP BY s.sid, s.name
HAVING COUNT (DISTINCT pr.jid) >= 2 

You join the three tables, then using sid as a grouping attribute (sname is functionally dependent on it, so it does not have an impact on the number of groups, but you must include it, otherwise it cannot be part of the select part of the statement). Then you are removing those that do not satisfy your condition: the satisfy pr.jid is >= 2, which is that you wanted originally.

Best solution to your problem

I personally prefer a simpler cleaner solution:

  1. You need to only group by Supplies (sid, pid, jid**, quantity) to find the sid of those that supply at least to two projects.
  2. Then join it to the Suppliers table to get the supplier same.

 SELECT sid, sname from
    (SELECT sid from supplies 
    GROUP BY sid, pid 
    HAVING count(DISTINCT jid) >= 2
    ) AS T1
NATURAL JOIN 
Supliers;

It will also be faster to execute, because the join is only done when needed, not all the times.

--dmg

Using only CSS, show div on hover over <a>

For me, if I want to interact with the hidden div without seeing it disappear each time I leave the triggering element (a in that case) I must add:

div:hover {
    display: block;
}

In SQL Server, how do I generate a CREATE TABLE statement for a given table?

Show create table in classic asp (handles constraints, primary keys, copying the table structure and/or data ...)

Sql server Show create table Mysql-style "Show create table" and "show create database" commands from Microsoft sql server. The script is written is Microsoft asp-language and is quite easy to port to another language.*

SimpleDateFormat returns 24-hour date: how to get 12-hour date?

SimpleDateFormat dateFormat = new SimpleDateFormat("dd/mm/yyyy hh:mm:ss a");

use hh in place of HH

how to configure apache server to talk to HTTPS backend server?

In my case, my server was configured to work only in https mode, and error occured when I try to access http mode. So changing http://my-service to https://my-service helped.

Get MAC address using shell script

This was the only thing that worked for me on Armbian:

dmesg | grep -oE 'mac=.*\w+' | cut -b '5-'

Android: Storing username and password?

You can also look at the SampleSyncAdapter sample from the SDK. It may help you.

Update Fragment from ViewPager

1) Create a handler in the fragment that you want to update.

public static Handler sUpdateHandler;

@Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        ...

        sUpdateHandler = new Handler(){
            @Override
            public void handleMessage(Message msg) {
                super.handleMessage(msg);
                // call you update method here.
            }
        };
    }

2) In the Activity/Fragment/Dialog, wherever you want the update call to be fired, get the reference to that handler and send a message (telling your fragment to update)

// Check if the fragment is visible by checking if the handler is null or not.
Handler handler = TaskTabCompletedFragment.sUpdateHandler;
if (handler != null) {
    handler.obtainMessage().sendToTarget();
}

Parse JSON from HttpURLConnection object

In addition, if you wish to parse your object in case of http error (400-5** codes), You can use the following code: (just replace 'getInputStream' with 'getErrorStream':

    BufferedReader rd = new BufferedReader(
            new InputStreamReader(conn.getErrorStream()));
    StringBuilder sb = new StringBuilder();
    String line;
    while ((line = rd.readLine()) != null) {
        sb.append(line);
    }
    rd.close();
    return sb.toString();

CSS technique for a horizontal line with words in the middle

I went for a simpler approach:

HTML

<div class="box">
  <h1 class="text">OK THEN LETS GO</h1>
  <hr class="line" />
</div>

CSS

.box {
  align-items: center;
  background: #ff7777;
  display: flex;
  height: 100vh;
  justify-content: center;
}

.line {
  border: 5px solid white;
  display: block;
  width: 100vw;
}

.text {
  background: #ff7777;
  color: white;
  font-family: sans-serif;
  font-size: 2.5rem;
  padding: 25px 50px;
  position: absolute;
}

Result

Result

How do I stretch an image to fit the whole background (100% height x 100% width) in Flutter?

I ran into problems with just an FittedBox so I wrapped my Image in an LayoutBuilder:

LayoutBuilder( 
   builder: (_, constraints) => Image(
      fit: BoxFit.fill,
      width: constraints.maxWidth,
      image: AssetImage(assets.example),
   ),
)

This worked like a charm and I suggest you give it a try.
Of course you can use height instead of width, this is just what I used.

Disable SSL fallback and use only TLS for outbound connections in .NET? (Poodle mitigation)

@watson

On windows forms it is available, at the top of the class put

  static void Main(string[] args)
    {
        ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12;
       //other stuff here
    }

since windows is single threaded, its all you need, in the event its a service you need to put it right above the call to the service (since there is no telling what thread you'll be on).

using System.Security.Principal 

is also needed.

Why are primes important in cryptography?

I think what are important in cryptography are not primes itself, but it is the difficulty of prime factorization problem

Suppose you have very very large integer which is known to be product of two primes m and n, it is not easy to find what are m and n. Algorithm such as RSA depends on this fact.

By the way, there is a published paper on algorithm which can "solve" this prime factorization problem in acceptable time using quantum computer. So newer algorithms in cryptography may not rely on this "difficulty" of prime factorization anymore when quantum computer comes to town :)

Triangle Draw Method

There is no direct method to draw a triangle. You can use drawPolygon() method for this. It takes three parameters in the following form: drawPolygon(int x[],int y[], int number_of_points); To draw a triangle: (Specify the x coordinates in array x and y coordinates in array y and number of points which will be equal to the elements of both the arrays.Like in triangle you will have 3 x coordinates and 3 y coordinates which means you have 3 points in total.) Suppose you want to draw the triangle using the following points:(100,50),(70,100),(130,100) Do the following inside public void paint(Graphics g):

int x[]={100,70,130};
int y[]={50,100,100};
g.drawPolygon(x,y,3);

Similarly you can draw any shape using as many points as you want.