Why does C++ code for testing the Collatz conjecture run faster than hand-written assembly?
As a generic answer, not specifically directed at this task: In many cases, you can significantly speed up any program by making improvements at a high level. Like calculating data once instead of multiple times, avoiding unnecessary work completely, using caches in the best way, and so on. These things are much easier to do in a high level language.
Writing assembler code, it is possible to improve on what an optimising compiler does, but it is hard work. And once it's done, your code is much harder to modify, so it is much more difficult to add algorithmic improvements. Sometimes the processor has functionality that you cannot use from a high level language, inline assembly is often useful in these cases and still lets you use a high level language.
In the Euler problems, most of the time you succeed by building something, finding why it is slow, building something better, finding why it is slow, and so on and so on. That is very, very hard using assembler. A better algorithm at half the possible speed will usually beat a worse algorithm at full speed, and getting the full speed in assembler isn't trivial.
How to convert image into byte array and byte array to base64 String in android?
I wrote the following code to convert an image from sdcard to a Base64 encoded string to send as a JSON object.And it works great:
String filepath = "/sdcard/temp.png";
File imagefile = new File(filepath);
FileInputStream fis = null;
try {
fis = new FileInputStream(imagefile);
} catch (FileNotFoundException e) {
e.printStackTrace();
}
Bitmap bm = BitmapFactory.decodeStream(fis);
ByteArrayOutputStream baos = new ByteArrayOutputStream();
bm.compress(Bitmap.CompressFormat.JPEG, 100 , baos);
byte[] b = baos.toByteArray();
encImage = Base64.encodeToString(b, Base64.DEFAULT);
Make Iframe to fit 100% of container's remaining height
Similar answer of @MichAdel, but I'm using JQuery and more elegant.
<script type="text/javascript">
$(document).ready(function() {
var $iframe = $('#iframe_id')[0];
// Calculate the total offset top of given jquery element
function totalOffsetTop($elem) {
return $elem.offsetTop + ($elem.offsetParent ? totalOffsetTop($elem.offsetParent) : 0);
}
function resizeIframe() {
var height = window.innerHeight || document.body.clientHeight || document.documentElement.clientHeight;
height -= totalOffsetTop($iframe);
$iframe.height = Math.max(0, height) + 'px';
}
$iframe.onload = resizeIframe();
window.onresize = resizeIframe;
});
</script>
iframe_id
is the ID of the iframe tag
How can I change the image of an ImageView?
If you created imageview using xml file then follow the steps.
Solution 1:
Step 1: Create an XML file
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="#cc8181"
>
<ImageView
android:id="@+id/image"
android:layout_width="50dip"
android:layout_height="fill_parent"
android:src="@drawable/icon"
android:layout_marginLeft="3dip"
android:scaleType="center"/>
</LinearLayout>
Step 2: create an Activity
ImageView img= (ImageView) findViewById(R.id.image);
img.setImageResource(R.drawable.my_image);
Solution 2:
If you created imageview from Java Class
ImageView img = new ImageView(this);
img.setImageResource(R.drawable.my_image);
How to find the length of a string in R
Use stringi
package and stri_length
function
> stri_length(c("ala ma kota","ABC",NA))
[1] 11 3 NA
Why? Because it is the FASTEST among presented solutions :)
require(microbenchmark)
require(stringi)
require(stringr)
x <- c(letters,NA,paste(sample(letters,2000,TRUE),collapse=" "))
microbenchmark(nchar(x),str_length(x),stri_length(x))
Unit: microseconds
expr min lq median uq max neval
nchar(x) 11.868 12.776 13.1590 13.6475 41.815 100
str_length(x) 30.715 33.159 33.6825 34.1360 173.400 100
stri_length(x) 2.653 3.281 4.0495 4.5380 19.966 100
and also works fine with NA's
nchar(NA)
## [1] 2
stri_length(NA)
## [1] NA
How do I capture response of form.submit
You can event.preventDefault()
in the click handler for your submit button to ensure that the HTML form default submit
event doesn't fire (which is what leads to the page refreshing).
Another alternative would be to use hackier form markup: It's the use of <form>
and type="submit"
that is getting in the way of the desired behavior here; as these ultimately lead to click events refreshing the page.
If you want to still use <form>
, and you don't want to write custom click handlers, you can use jQuery's ajax
method, which abstracts the entire problem away for you by exposing promise methods for success
, error
, etc.
To recap, you can solve your problem by either:
• preventing default behavior in the handling function by using event.preventDefault()
• using elements that don't have default behavior (e.g. <form>
)
• using jQuery ajax
(i just noticed this question is from 2008, not sure why it showed up in my feed; at any rate, hopefully this is a clear answer)
What's the longest possible worldwide phone number I should consider in SQL varchar(length) for phone
As for "phone numbers" you should really consider the difference between a "subscriber number" and a "dialling number" and the possible formatting options of them.
A subscriber number is generally defined in the national numbering plans. The question itself shows a relation to a national view by mentioning "area code" which a lot of nations don't have. ITU has assembled an overview of the world's numbering plans publishing recommendation E.164 where the national number was found to have a maximum of 12 digits. With international direct distance calling (DDD) defined by a country code of 1 to 3 digits they added that up to 15 digits ... without formatting.
The dialling number is a different thing as there are network elements that can interpret exta values in a phone number. You may think of an answering machine and a number code that sets the call diversion parameters. As it may contain another subscriber number it must be obviously longer than its base value. RFC 4715 has set aside 20 bcd-encoded bytes for "subaddressing".
If you turn to the technical limitation then it gets even more as the subscriber number has a technical limit in the 10 bcd-encoded bytes in the 3GPP standards (like GSM) and ISDN standards (like DSS1). They have a seperate TON/NPI byte for the prefix (type of number / number plan indicator) which E.164 recommends to be written with a "+" but many number plans define it with up to 4 numbers to be dialled.
So if you want to be future proof (and many software systems run unexpectingly for a few decades) you would need to consider 24 digits for a subscriber number and 64 digits for a dialling number as the limit ... without formatting. Adding formatting may add roughly an extra character for every digit. So as a final thought it may not be a good idea to limit the phone number in the database in any way and leave shorter limits to the UX designers.
How to iterate a loop with index and element in Swift
Swift 5 provides a method called enumerated()
for Array
. enumerated()
has the following declaration:
func enumerated() -> EnumeratedSequence<Array<Element>>
Returns a sequence of pairs (n, x), where n represents a consecutive integer starting at zero and x represents an element of the sequence.
In the simplest cases, you may use enumerated()
with a for loop. For example:
let list = ["Car", "Bike", "Plane", "Boat"]
for (index, element) in list.enumerated() {
print(index, ":", element)
}
/*
prints:
0 : Car
1 : Bike
2 : Plane
3 : Boat
*/
Note however that you're not limited to use enumerated()
with a for loop. In fact, if you plan to use enumerated()
with a for loop for something similar to the following code, you're doing it wrong:
let list = [Int](1...5)
var arrayOfTuples = [(Int, Int)]()
for (index, element) in list.enumerated() {
arrayOfTuples += [(index, element)]
}
print(arrayOfTuples) // prints [(0, 1), (1, 2), (2, 3), (3, 4), (4, 5)]
A swiftier way to do this is:
let list = [Int](1...5)
let arrayOfTuples = Array(list.enumerated())
print(arrayOfTuples) // prints [(offset: 0, element: 1), (offset: 1, element: 2), (offset: 2, element: 3), (offset: 3, element: 4), (offset: 4, element: 5)]
As an alternative, you may also use enumerated()
with map
:
let list = [Int](1...5)
let arrayOfDictionaries = list.enumerated().map { (a, b) in return [a : b] }
print(arrayOfDictionaries) // prints [[0: 1], [1: 2], [2: 3], [3: 4], [4: 5]]
Moreover, although it has some limitations, forEach
can be a good replacement to a for loop:
let list = [Int](1...5)
list.reversed().enumerated().forEach { print($0, ":", $1) }
/*
prints:
0 : 5
1 : 4
2 : 3
3 : 2
4 : 1
*/
By using enumerated()
and makeIterator()
, you can even iterate manually on your Array
. For example:
import UIKit
import PlaygroundSupport
class ViewController: UIViewController {
var generator = ["Car", "Bike", "Plane", "Boat"].enumerated().makeIterator()
override func viewDidLoad() {
super.viewDidLoad()
let button = UIButton(type: .system)
button.setTitle("Tap", for: .normal)
button.frame = CGRect(x: 100, y: 100, width: 100, height: 100)
button.addTarget(self, action: #selector(iterate(_:)), for: .touchUpInside)
view.addSubview(button)
}
@objc func iterate(_ sender: UIButton) {
let tuple = generator.next()
print(String(describing: tuple))
}
}
PlaygroundPage.current.liveView = ViewController()
/*
Optional((offset: 0, element: "Car"))
Optional((offset: 1, element: "Bike"))
Optional((offset: 2, element: "Plane"))
Optional((offset: 3, element: "Boat"))
nil
nil
nil
*/
Use python requests to download CSV
To simplify these answers, and increase performance when downloading a large file, the below may work a bit more efficiently.
import requests
from contextlib import closing
import csv
url = "http://download-and-process-csv-efficiently/python.csv"
with closing(requests.get(url, stream=True)) as r:
reader = csv.reader(r.iter_lines(), delimiter=',', quotechar='"')
for row in reader:
print row
By setting stream=True
in the GET request, when we pass r.iter_lines()
to csv.reader(), we are passing a generator to csv.reader(). By doing so, we enable csv.reader() to lazily iterate over each line in the response with for row in reader
.
This avoids loading the entire file into memory before we start processing it, drastically reducing memory overhead for large files.
How to assign a heredoc value to a variable in Bash?
Thanks to dimo414's answer, this shows how his great solution works, and shows that you can have quotes and variables in the text easily as well:
example output
$ ./test.sh
The text from the example function is:
Welcome dev: Would you "like" to know how many 'files' there are in /tmp?
There are " 38" files in /tmp, according to the "wc" command
test.sh
#!/bin/bash
function text1()
{
COUNT=$(\ls /tmp | wc -l)
cat <<EOF
$1 Would you "like" to know how many 'files' there are in /tmp?
There are "$COUNT" files in /tmp, according to the "wc" command
EOF
}
function main()
{
OUT=$(text1 "Welcome dev:")
echo "The text from the example function is: $OUT"
}
main
Is there a way to represent a directory tree in a Github README.md?
I made a node module to automate this task: mddir
Usage
node mddir "../relative/path/"
To install: npm install mddir -g
To generate markdown for current directory: mddir
To generate for any absolute path: mddir /absolute/path
To generate for a relative path: mddir ~/Documents/whatever.
The md file gets generated in your working directory.
Currently ignores node_modules, and .git folders.
Troubleshooting
If you receive the error 'node\r: No such file or directory', the issue is that your operating system uses different line endings and mddir can't parse them without you explicitly setting the line ending style to Unix. This usually affects Windows, but also some versions of Linux. Setting line endings to Unix style has to be performed within the mddir npm global bin folder.
Line endings fix
Get npm bin folder path with:
npm config get prefix
Cd into that folder
brew install dos2unix
dos2unix lib/node_modules/mddir/src/mddir.js
This converts line endings to Unix instead of Dos
Then run as normal with: node mddir "../relative/path/".
Example generated markdown file structure 'directoryList.md'
|-- .bowerrc
|-- .jshintrc
|-- .jshintrc2
|-- Gruntfile.js
|-- README.md
|-- bower.json
|-- karma.conf.js
|-- package.json
|-- app
|-- app.js
|-- db.js
|-- directoryList.md
|-- index.html
|-- mddir.js
|-- routing.js
|-- server.js
|-- _api
|-- api.groups.js
|-- api.posts.js
|-- api.users.js
|-- api.widgets.js
|-- _components
|-- directives
|-- directives.module.js
|-- vendor
|-- directive.draganddrop.js
|-- helpers
|-- helpers.module.js
|-- proprietary
|-- factory.actionDispatcher.js
|-- services
|-- services.cardTemplates.js
|-- services.cards.js
|-- services.groups.js
|-- services.posts.js
|-- services.users.js
|-- services.widgets.js
|-- _mocks
|-- mocks.groups.js
|-- mocks.posts.js
|-- mocks.users.js
|-- mocks.widgets.js
jquery animate .css
The example from jQuery's website animates size AND font but you could easily modify it to fit your needs
$("#go").click(function(){
$("#block").animate({
width: "70%",
opacity: 0.4,
marginLeft: "0.6in",
fontSize: "3em",
borderWidth: "10px"
}, 1500 );
http://api.jquery.com/animate/
SQL: Two select statements in one query
You can combine data from the two tables, order by goals highest first and then choose the top two like this:
MySQL
select *
from (
select * from tblMadrid
union all
select * from tblBarcelona
) alldata
order by goals desc
limit 0,2;
SQL Server
select top 2 *
from (
select * from tblMadrid
union all
select * from tblBarcelona
) alldata
order by goals desc;
If you only want Messi and Ronaldo
select * from tblBarcelona where name = 'messi'
union all
select * from tblMadrid where name = 'ronaldo'
To ensure that messi is at the top of the result, you can do something like this:
select * from (
select * from tblBarcelona where name = 'messi'
union all
select * from tblMadrid where name = 'ronaldo'
) stars
order by name;
How to run a jar file in a linux commandline
copy your file in linux Java directory
cp yourfile.jar /java/bin
open the directory
cd /java/bin
and execute your file
./java -jar yourfile.jar
or all in one try this command:
/java/bin/java -jar jarfilefolder/jarfile.jar
How to get JSON response from http.Get
The ideal way is not to use ioutil.ReadAll
, but rather use a decoder on the reader directly. Here's a nice function that gets a url and decodes its response onto a target
structure.
var myClient = &http.Client{Timeout: 10 * time.Second}
func getJson(url string, target interface{}) error {
r, err := myClient.Get(url)
if err != nil {
return err
}
defer r.Body.Close()
return json.NewDecoder(r.Body).Decode(target)
}
Example use:
type Foo struct {
Bar string
}
func main() {
foo1 := new(Foo) // or &Foo{}
getJson("http://example.com", foo1)
println(foo1.Bar)
// alternately:
foo2 := Foo{}
getJson("http://example.com", &foo2)
println(foo2.Bar)
}
You should not be using the default *http.Client
structure in production as this answer originally demonstrated! (Which is what http.Get
/etc call to). The reason is that the default client has no timeout set; if the remote server is unresponsive, you're going to have a bad day.
Rotate a div using javascript
To rotate a DIV we can add some CSS that, well, rotates the DIV using CSS transform rotate.
To toggle the rotation we can keep a flag, a simple variable with a boolean value that tells us what way to rotate.
var rotated = false;
document.getElementById('button').onclick = function() {
var div = document.getElementById('div'),
deg = rotated ? 0 : 66;
div.style.webkitTransform = 'rotate('+deg+'deg)';
div.style.mozTransform = 'rotate('+deg+'deg)';
div.style.msTransform = 'rotate('+deg+'deg)';
div.style.oTransform = 'rotate('+deg+'deg)';
div.style.transform = 'rotate('+deg+'deg)';
rotated = !rotated;
}
_x000D_
_x000D_
var rotated = false;_x000D_
_x000D_
document.getElementById('button').onclick = function() {_x000D_
var div = document.getElementById('div'),_x000D_
deg = rotated ? 0 : 66;_x000D_
_x000D_
div.style.webkitTransform = 'rotate('+deg+'deg)'; _x000D_
div.style.mozTransform = 'rotate('+deg+'deg)'; _x000D_
div.style.msTransform = 'rotate('+deg+'deg)'; _x000D_
div.style.oTransform = 'rotate('+deg+'deg)'; _x000D_
div.style.transform = 'rotate('+deg+'deg)'; _x000D_
_x000D_
rotated = !rotated;_x000D_
}
_x000D_
#div {_x000D_
position:relative; _x000D_
height: 200px; _x000D_
width: 200px; _x000D_
margin: 30px;_x000D_
background: red;_x000D_
}
_x000D_
<button id="button">rotate</button>_x000D_
<br /><br />_x000D_
<div id="div"></div>
_x000D_
_x000D_
_x000D_
To add some animation to the rotation all we have to do is add CSS transitions
div {
-webkit-transition: all 0.5s ease-in-out;
-moz-transition: all 0.5s ease-in-out;
-o-transition: all 0.5s ease-in-out;
transition: all 0.5s ease-in-out;
}
_x000D_
_x000D_
var rotated = false;_x000D_
_x000D_
document.getElementById('button').onclick = function() {_x000D_
var div = document.getElementById('div'),_x000D_
deg = rotated ? 0 : 66;_x000D_
_x000D_
div.style.webkitTransform = 'rotate('+deg+'deg)'; _x000D_
div.style.mozTransform = 'rotate('+deg+'deg)'; _x000D_
div.style.msTransform = 'rotate('+deg+'deg)'; _x000D_
div.style.oTransform = 'rotate('+deg+'deg)'; _x000D_
div.style.transform = 'rotate('+deg+'deg)'; _x000D_
_x000D_
rotated = !rotated;_x000D_
}
_x000D_
#div {_x000D_
position:relative; _x000D_
height: 200px; _x000D_
width: 200px; _x000D_
margin: 30px;_x000D_
background: red;_x000D_
-webkit-transition: all 0.5s ease-in-out;_x000D_
-moz-transition: all 0.5s ease-in-out;_x000D_
-o-transition: all 0.5s ease-in-out;_x000D_
transition: all 0.5s ease-in-out;_x000D_
}
_x000D_
<button id="button">rotate</button>_x000D_
<br /><br />_x000D_
<div id="div"></div>
_x000D_
_x000D_
_x000D_
Another way to do it is using classes, and setting all the styles in a stylesheet, thus keeping them out of the javascript
document.getElementById('button').onclick = function() {
document.getElementById('div').classList.toggle('rotated');
}
_x000D_
_x000D_
document.getElementById('button').onclick = function() {_x000D_
document.getElementById('div').classList.toggle('rotated');_x000D_
}
_x000D_
#div {_x000D_
position:relative; _x000D_
height: 200px; _x000D_
width: 200px; _x000D_
margin: 30px;_x000D_
background: red;_x000D_
-webkit-transition: all 0.5s ease-in-out;_x000D_
-moz-transition: all 0.5s ease-in-out;_x000D_
-o-transition: all 0.5s ease-in-out;_x000D_
transition: all 0.5s ease-in-out;_x000D_
}_x000D_
_x000D_
#div.rotated {_x000D_
-webkit-transform : rotate(66deg); _x000D_
-moz-transform : rotate(66deg); _x000D_
-ms-transform : rotate(66deg); _x000D_
-o-transform : rotate(66deg); _x000D_
transform : rotate(66deg); _x000D_
}
_x000D_
<button id="button">rotate</button>_x000D_
<br /><br />_x000D_
<div id="div"></div>
_x000D_
_x000D_
_x000D_
How do I post form data with fetch api?
With fetch api it turned out that you do NOT have to include headers "Content-type": "multipart/form-data".
So the following works:
let formData = new FormData()
formData.append("nameField", fileToSend)
fetch(yourUrlToPost, {
method: "POST",
body: formData
})
Note that with axios I had to use the content-type.
getElementById returns null?
Also be careful how you execute the js on the page. For example if you do something like this:
(function(window, document, undefined){
var foo = document.getElementById("foo");
console.log(foo);
})(window, document, undefined);
This will return null because you'd be calling the document before it was loaded.
Better option..
(function(window, document, undefined){
// code that should be taken care of right away
window.onload = init;
function init(){
// the code to be called when the dom has loaded
// #document has its nodes
}
})(window, document, undefined);
How can I remove a button or make it invisible in Android?
IF you want to make invisible button, then use this:
<Button ... android:visibility="gone"/>
View.INVISIBLE:
Button will become transparent. But it taking space.
View.GONE
Button will be completely remove from the layout and we can add other widget in the place of removed button.
Importing data from a JSON file into R
First install the RJSONIO and RCurl package:
_x000D_
_x000D_
install.packages("RJSONIO")_x000D_
install.packages("(RCurl")
_x000D_
_x000D_
_x000D_
Try below code using RJSONIO in console
_x000D_
_x000D_
library(RJSONIO)_x000D_
library(RCurl)_x000D_
json_file = getURL("https://raw.githubusercontent.com/isrini/SI_IS607/master/books.json")_x000D_
json_file2 = RJSONIO::fromJSON(json_file)_x000D_
head(json_file2)
_x000D_
_x000D_
_x000D_
Pass request headers in a jQuery AJAX GET call
As of jQuery 1.5, there is a headers
hash you can pass in as follows:
$.ajax({
url: "/test",
headers: {"X-Test-Header": "test-value"}
});
From http://api.jquery.com/jQuery.ajax:
headers (added 1.5): A map of additional header key/value pairs to send along with the request. This setting is set before the beforeSend function is called; therefore, any values in the headers setting can be overwritten from within the beforeSend function.
Unable to call the built in mb_internal_encoding method?
If you don't know how to enable php_mbstring extension in windows, open your php.ini and remove the semicolon before the extension:
change this
;extension=php_mbstring.dll
to this
extension=php_mbstring.dll
after modification, you need to reset your php server.
What is the best way to know if all the variables in a Class are null?
The best way in my opinion is Reflection as others have recommended. Here's a sample that evaluates each local field for null. If it finds one that is not null, method will return false.
public class User {
String id = null;
String name = null;
public String getId() {
return id;
}
public void setId(String id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public boolean isNull() {
Field fields[] = this.getClass().getDeclaredFields();
for (Field f : fields) {
try {
Object value = f.get(this);
if (value != null) {
return false;
}
}
catch (IllegalArgumentException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
catch (IllegalAccessException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
return true;
}
public static void main(String args[]) {
System.out.println(new User().isNull());
}
}
How to draw circle in html page?
The followings are my 9 solutions. Feel free to insert text into the divs or svg elements.
- border-radius
- clip-path
- html entity
- pseudo element
- radial-gradient
- svg circle & path
- canvas arc()
- img tag
- pre tag
_x000D_
_x000D_
var c = document.getElementById('myCanvas');
var ctx = c.getContext('2d');
ctx.beginPath();
ctx.arc(50, 50, 50, 0, 2 * Math.PI);
ctx.fillStyle = '#B90136';
ctx.fill();
_x000D_
#circle1 {
background-color: #B90136;
width: 100px;
height: 100px;
border-radius: 50px;
}
#circle2 {
background-color: #B90136;
width: 100px;
height: 100px;
clip-path: circle();
}
#circle3 {
color: #B90136;
font-size: 100px;
line-height: 100px;
}
#circle4::before {
content: "";
display: block;
width: 100px;
height: 100px;
border-radius: 50px;
background-color: #B90136;
}
#circle5 {
background-image: radial-gradient(#B90136 70%, transparent 30%);
height: 100px;
width: 100px;
}
_x000D_
<h3>1 border-radius</h3>
<div id="circle1"></div>
<hr/>
<h3>2 clip-path</h3>
<div id="circle2"></div>
<hr/>
<h3>3 html entity</h3>
<div id="circle3">⬤</div>
<hr/>
<h3>4 pseudo element</h3>
<div id="circle4"></div>
<hr/>
<h3>5 radial-gradient</h3>
<div id="circle5"></div>
<hr/>
<h3>6 svg circle & path</h3>
<svg width="100" height="100">
<circle cx="50" cy="50" r="50" fill="#B90136" />
</svg>
<hr/>
<h3>7 canvas arc()</h3>
<canvas id="myCanvas" width="100" height="100"></canvas>
<hr/>
<h3>8 img tag</h3>
<img src="circle.png" width="100" height="100" />
<hr/>
<h3>9 pre tag</h3>
<pre style="line-height:8px;">
+++
+++++
+++++++
+++++++++
+++++++++++
+++++++++++
+++++++++++
+++++++++
+++++++
+++++
+++
</pre>
_x000D_
_x000D_
_x000D_
PostgreSQL ERROR: canceling statement due to conflict with recovery
No need to touch hot_standby_feedback
. As others have mentioned, setting it to on
can bloat master. Imagine opening transaction on a slave and not closing it.
Instead, set max_standby_archive_delay
and max_standby_streaming_delay
to some sane value:
# /etc/postgresql/10/main/postgresql.conf on a slave
max_standby_archive_delay = 900s
max_standby_streaming_delay = 900s
This way queries on slaves with a duration less than 900 seconds won't be cancelled. If your workload requires longer queries, just set these options to a higher value.
Angular: Cannot Get /
This error can apparently happen for a number of reasons. Here is my experience for those who land here after searching for "Cannot GET /"
I experienced this error when I installed ng-bootstrap v6 into an Angular 8 project. I downgraded ng-bootstrap to v5 and it seems to be okay now, since ng-bootstrap v6 is only compatible with Angular 9.
This happened while working in Visual Studio 2019 with the Angular .NET Core template. At the same time, the output panel of Visual Studio displayed this esoteric sounding error: "TS1086: An accessor cannot be declared in ambient context," which led me here, which, after a little reading, made me think it was a versioning issue. It appears that it was.
I fixed it by changing "@ng-bootstrap/ng-bootstrap": "^6.0.0"," to "@ng-bootstrap/ng-bootstrap": "^5.0.0" in the package.json file and rebuilding.
How to select the last record of a table in SQL?
Assuming you have an Id column:
SELECT TOP 1 *
FROM table
ORDER
BY Id DESC;
Also, this will work on SQL Server. I think that MySQL you might need to use:
SELECT *
FROM table
ORDER
BY Id DESC
LIMIT 1
But, I'm not 100% sure about this.
EDIT
Looking at the other answers, I'm now 100% confident that I'm correct with the MySQL statement :o)
EDIT
Just seen your latest comment. You could do:
SELECT MAX(Id)
FROM table
This will get you the highest Id number.
byte array to pdf
You shouldn't be using the BinaryFormatter
for this - that's for serializing .Net types to a binary file so they can be read back again as .Net types.
If it's stored in the database, hopefully, as a varbinary
- then all you need to do is get the byte array from that (that will depend on your data access technology - EF and Linq to Sql, for example, will create a mapping that makes it trivial to get a byte array) and then write it to the file as you do in your last line of code.
With any luck - I'm hoping that fileContent
here is the byte array? In which case you can just do
System.IO.File.WriteAllBytes("hello.pdf", fileContent);
Return Boolean Value on SQL Select Statement
Given that commonly 1 = true
and 0 = false
, all you need to do is count the number of rows, and cast to a boolean
.
Hence, your posted code only needs a COUNT()
function added:
SELECT CAST(COUNT(1) AS BIT) AS Expr1
FROM [User]
WHERE (UserID = 20070022)
android:drawableLeft margin and/or padding
I'll throw my answer into the ring as well. If you want to do this programmatically you can do the following.
final Drawable drawable = ContextCompat.getDrawable(getContext(), R.drawable.somedrawable);
final boolean isLTR = ViewCompat.LAYOUT_DIRECTION_LTR == ViewCompat.getLayoutDirection(this);
final int iconInsetPadding = getResources().getDimensionPixelSize(R.dimen.icon_padding);
final Drawable insetDrawable = new InsetDrawable(drawable, isLTR ? 0 : iconInsetPadding, 0, isLTR ? iconInsetPadding : 0, 0);
This will add the padding to the end of the drawable where end will mean left/right depending if phone is in LTR or RTL.
Equivalent of varchar(max) in MySQL?
The max length of a varchar is
65535
divided by the max byte length of a character in the character set the column is set to (e.g. utf8=3 bytes, ucs2=2, latin1=1).
minus 2 bytes to store the length
minus the length of all the other columns
minus 1 byte for every 8 columns that are nullable. If your column is null/not null this gets stored as one bit in a byte/bytes called the null mask, 1 bit per column that is nullable.
How to include duplicate keys in HashMap?
Use Map<Integer, List<String>>
:
Map<Integer, List<String>> map = new LinkedHashMap< Integer, List<String>>();
map.put(-1505711364, new ArrayList<>(Arrays.asList("4")));
map.put(294357273, new ArrayList<>(Arrays.asList("15", "71")));
//...
To add a new key/value pair in this map:
public void add(Integer key, String newValue) {
List<String> currentValue = map.get(key);
if (currentValue == null) {
currentValue = new ArrayList<String>();
map.put(key, currentValue);
}
currentValue.add(newValue);
}
T-SQL query to show table definition?
I know it's an old question, but exactly what I was looking for. Because I want to batch script some tables, I rewrote the C# code from Anthony Faull for PowerShell.
This one is uses Integrated Security:
Import-Module sqlps
$serverInstance = "<server>"
$database = "<database>"
$table = "<table>"
$schema = "<schema>"
$options = New-Object -TypeName Microsoft.SqlServer.Management.Smo.ScriptingOptions
$options.DriAll = $true
$options.SchemaQualify = $true
$connection = New-Object -TypeName Microsoft.SqlServer.Management.Common.ServerConnection `
-ArgumentList $serverInstance
$server = New-Object -TypeName Microsoft.SqlServer.Management.Smo.Server `
-ArgumentList $connection
$server.Databases.Item($database).Tables.Item($table, $schema).Script($options) `
| ForEach-Object -Process { $_ + "`nGO"}
And here with username and password:
Import-Module sqlps
$serverInstance = "<server>"
$user = "<user>"
$password = "<pasword>"
$database = "<database>"
$table = "<table>"
$schema = "<schema>"
$options = New-Object -TypeName Microsoft.SqlServer.Management.Smo.ScriptingOptions
$options.DriAll = $true
$options.SchemaQualify = $true
$connection = New-Object -TypeName Microsoft.SqlServer.Management.Common.ServerConnection `
-ArgumentList $serverInstance
$connection.LoginSecure = $false
$connection.Login = $user
$connection.Password = $password
$server = New-Object -TypeName Microsoft.SqlServer.Management.Smo.Server `
-ArgumentList $connection
$server.Databases.Item($database).Tables.Item($table, $schema).Script($options) `
| ForEach-Object -Process { $_ + "`nGO"}
iPhone UITextField - Change placeholder text color
In Swift:
if let placeholder = yourTextField.placeholder {
yourTextField.attributedPlaceholder = NSAttributedString(string:placeholder,
attributes: [NSForegroundColorAttributeName: UIColor.blackColor()])
}
In Swift 4.0:
if let placeholder = yourTextField.placeholder {
yourTextField.attributedPlaceholder = NSAttributedString(string:placeholder,
attributes: [NSAttributedStringKey.foregroundColor: UIColor.black])
}
C++ callback using class member
If you have callbacks with different parameters you can use templates as follows:
// compile with: g++ -std=c++11 myTemplatedCPPcallbacks.cpp -o myTemplatedCPPcallbacksApp
#include <functional> // c++11
#include <iostream> // due to: cout
using std::cout;
using std::endl;
class MyClass
{
public:
MyClass();
static void Callback(MyClass* instance, int x);
private:
int private_x;
};
class OtherClass
{
public:
OtherClass();
static void Callback(OtherClass* instance, std::string str);
private:
std::string private_str;
};
class EventHandler
{
public:
template<typename T, class T2>
void addHandler(T* owner, T2 arg2)
{
cout << "\nHandler added..." << endl;
//Let's pretend an event just occured
owner->Callback(owner, arg2);
}
};
MyClass::MyClass()
{
EventHandler* handler;
private_x = 4;
handler->addHandler(this, private_x);
}
OtherClass::OtherClass()
{
EventHandler* handler;
private_str = "moh ";
handler->addHandler(this, private_str );
}
void MyClass::Callback(MyClass* instance, int x)
{
cout << " MyClass::Callback(MyClass* instance, int x) ==> "
<< 6 + x + instance->private_x << endl;
}
void OtherClass::Callback(OtherClass* instance, std::string private_str)
{
cout << " OtherClass::Callback(OtherClass* instance, std::string private_str) ==> "
<< " Hello " << instance->private_str << endl;
}
int main(int argc, char** argv)
{
EventHandler* handler;
handler = new EventHandler();
MyClass* myClass = new MyClass();
OtherClass* myOtherClass = new OtherClass();
}
Javascript Equivalent to PHP Explode()
var str = "helloword~this~is~me";
var exploded = str.splice(~);
the exploded variable will return array and you can access elements of the array be accessing it true exploded[nth] where nth is the index of the value you want to get
Can't connect to local MySQL server through socket '/var/mysql/mysql.sock' (38)
If your file my.cnf (usually in the /etc/mysql/ folder) is correctly configured with
socket=/var/lib/mysql/mysql.sock
you can check if mysql is running with the following command:
mysqladmin -u root -p status
try changing your permission to mysql folder. If you are working locally, you can try:
sudo chmod -R 755 /var/lib/mysql/
that solved it for me
How to calculate the difference between two dates using PHP?
An easy function
function time_difference($time_1, $time_2, $limit = null)
{
$val_1 = new DateTime($time_1);
$val_2 = new DateTime($time_2);
$interval = $val_1->diff($val_2);
$output = array(
"year" => $interval->y,
"month" => $interval->m,
"day" => $interval->d,
"hour" => $interval->h,
"minute" => $interval->i,
"second" => $interval->s
);
$return = "";
foreach ($output AS $key => $value) {
if ($value == 1)
$return .= $value . " " . $key . " ";
elseif ($value >= 1)
$return .= $value . " " . $key . "s ";
if ($key == $limit)
return trim($return);
}
return trim($return);
}
Use like
echo time_difference ($time_1, $time_2, "day");
Will return like 2 years 8 months 2 days
Oracle SQL update based on subquery between two tables
As you've noticed, you have no selectivity to your update statement so it is updating your entire table. If you want to update specific rows (ie where the IDs match) you probably want to do a coordinated subquery.
However, since you are using Oracle, it might be easier to create a materialized view for your query table and let Oracle's transaction mechanism handle the details. MVs work exactly like a table for querying semantics, are quite easy to set up, and allow you to specify the refresh interval.
Better way to sum a property value in an array
I'm not sure this has been mentioned yet. But there is a lodash function for that. Snippet below where value is your attribute to sum is 'value'.
_.sumBy(objects, 'value');
_.sumBy(objects, function(o) { return o.value; });
Both will work.
What causes the Broken Pipe Error?
When peer close, you just do not know whether it just stop sending or both sending and receiving.Because TCP allows this, btw, you should know the difference between close and shutdown.
If peer both stop sending and receiving, first you send some bytes, it will succeed. But the peer kernel will send you RST. So subsequently you send some bytes, your kernel will send you SIGPIPE signal, if you catch or ignore this signal, when your send returns, you just get Broken pipe error, or if you don't , the default behavior of your program is crashing.
Creating an instance using the class name and calling constructor
Yes, something like:
Class<?> clazz = Class.forName(className);
Constructor<?> ctor = clazz.getConstructor(String.class);
Object object = ctor.newInstance(new Object[] { ctorArgument });
That will only work for a single string parameter of course, but you can modify it pretty easily.
Note that the class name has to be a fully-qualified one, i.e. including the namespace. For nested classes, you need to use a dollar (as that's what the compiler uses). For example:
package foo;
public class Outer
{
public static class Nested {}
}
To obtain the Class
object for that, you'd need Class.forName("foo.Outer$Nested")
.
Flutter: Setting the height of the AppBar
You can use PreferredSize:
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Example',
home: Scaffold(
appBar: PreferredSize(
preferredSize: Size.fromHeight(50.0), // here the desired height
child: AppBar(
// ...
)
),
body: // ...
)
);
}
}
Write code to convert given number into words (eg 1234 as input should output one thousand two hundred and thirty four)
#include<stdio.h>
#include<conio.h>
void main()
{
int len=0,revnum,i,dup=0,j=0,k=0;
long int gvalue;
char ones[] [10]={"one","Two","Three","Four","Five","Six","Seven","Eight","Nine","Eleven","Twelve","Thirteen","Fourteen","Fifteen","Sixteen","Seventeen","Eighteen","Nineteen",""};
char twos[][10]={"Ten","Twenty","Thirty","Fourty","fifty","Sixty","Seventy","eighty","Ninety",""};
clrscr();
printf("\n Enter value");
scanf("%ld",&gvalue);
if(gvalue==10)
printf("Ten");
else if(gvalue==100)
printf("Hundred");
else if(gvalue==1000)
printf("Thousand");
dup=gvalue;
for(i=0;dup>0;i++)
{
revnum=revnum*10+dup%10;
len++;
dup=dup/10;
}
while(j<len)
{
if(gvalue<10)
{
printf("%s ",ones[gvalue-1]);
}
else if(gvalue>10&&gvalue<=19)
{
printf("%s ",ones[gvalue-2]);
break;
}
else if(gvalue>19&&gvalue<100)
{
k=gvalue/10;
gvalue=gvalue%10;
printf("%s ",twos[k-1]);
}
else if(gvalue>100&&gvalue<1000)
{
k=gvalue/100;
gvalue=gvalue%100;
printf("%s Hundred ",ones[k-1]);
}
else if(gvalue>=1000&&gvlaue<9999)
{
k=gvalue/1000;
gvalue=gvalue%1000;
printf("%s Thousand ",ones[k-1]);
}
else if(gvalue>=11000&&gvalue<=19000)
{
k=gvalue/1000;
gvalue=gvalue%1000;
printf("%s Thousand ",twos[k-2]);
}
else if(gvalue>=12000&&gvalue<100000)
{
k=gvalue/10000;
gvalue=gvalue%10000;
printf("%s ",ones[gvalue-1]);
}
else
{
printf("");
}
j++;
getch();
}
Show div on scrollDown after 800px
You've got a few things going on there. One, why a class? Do you actually have multiple of these on the page? The CSS suggests you can't. If not you should use an ID - it's faster to select both in CSS and jQuery:
<div id=bottomMenu>You read it all.</div>
Second you've got a few crazy things going on in that CSS - in particular the z-index is supposed to just be a number, not measured in pixels. It specifies what layer this tag is on, where each higher number is closer to the user (or put another way, on top of/occluding tags with lower z-indexes).
The animation you're trying to do is basically .fadeIn(), so just set the div to display: none; initially and use .fadeIn() to animate it:
$('#bottomMenu').fadeIn(2000);
.fadeIn() works by first doing display: (whatever the proper display property is for the tag), opacity: 0, then gradually ratcheting up the opacity.
Full working example:
http://jsfiddle.net/b9chris/sMyfT/
CSS:
#bottomMenu {
display: none;
position: fixed;
left: 0; bottom: 0;
width: 100%; height: 60px;
border-top: 1px solid #000;
background: #fff;
z-index: 1;
}
JS:
var $win = $(window);
function checkScroll() {
if ($win.scrollTop() > 100) {
$win.off('scroll', checkScroll);
$('#bottomMenu').fadeIn(2000);
}
}
$win.scroll(checkScroll);
Firing a Keyboard Event in Safari, using JavaScript
Did you dispatch the event correctly?
function simulateKeyEvent(character) {
var evt = document.createEvent("KeyboardEvent");
(evt.initKeyEvent || evt.initKeyboardEvent)("keypress", true, true, window,
0, 0, 0, 0,
0, character.charCodeAt(0))
var canceled = !body.dispatchEvent(evt);
if(canceled) {
// A handler called preventDefault
alert("canceled");
} else {
// None of the handlers called preventDefault
alert("not canceled");
}
}
If you use jQuery, you could do:
function simulateKeyPress(character) {
jQuery.event.trigger({ type : 'keypress', which : character.charCodeAt(0) });
}
How to encrypt and decrypt String with my passphrase in Java (Pc not mobile platform)?
package com.ezeon.util.gen;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.security.InvalidAlgorithmParameterException;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.security.spec.AlgorithmParameterSpec;
import java.security.spec.InvalidKeySpecException;
import java.security.spec.KeySpec;
import javax.crypto.*;
import javax.crypto.spec.PBEKeySpec;
import javax.crypto.spec.PBEParameterSpec;
/*** Encryption and Decryption of String data; PBE(Password Based Encryption and Decryption)
* @author Vikram
*/
public class CryptoUtil
{
Cipher ecipher;
Cipher dcipher;
// 8-byte Salt
byte[] salt = {
(byte) 0xA9, (byte) 0x9B, (byte) 0xC8, (byte) 0x32,
(byte) 0x56, (byte) 0x35, (byte) 0xE3, (byte) 0x03
};
// Iteration count
int iterationCount = 19;
public CryptoUtil() {
}
/**
*
* @param secretKey Key used to encrypt data
* @param plainText Text input to be encrypted
* @return Returns encrypted text
* @throws java.security.NoSuchAlgorithmException
* @throws java.security.spec.InvalidKeySpecException
* @throws javax.crypto.NoSuchPaddingException
* @throws java.security.InvalidKeyException
* @throws java.security.InvalidAlgorithmParameterException
* @throws java.io.UnsupportedEncodingException
* @throws javax.crypto.IllegalBlockSizeException
* @throws javax.crypto.BadPaddingException
*
*/
public String encrypt(String secretKey, String plainText)
throws NoSuchAlgorithmException,
InvalidKeySpecException,
NoSuchPaddingException,
InvalidKeyException,
InvalidAlgorithmParameterException,
UnsupportedEncodingException,
IllegalBlockSizeException,
BadPaddingException {
//Key generation for enc and desc
KeySpec keySpec = new PBEKeySpec(secretKey.toCharArray(), salt, iterationCount);
SecretKey key = SecretKeyFactory.getInstance("PBEWithMD5AndDES").generateSecret(keySpec);
// Prepare the parameter to the ciphers
AlgorithmParameterSpec paramSpec = new PBEParameterSpec(salt, iterationCount);
//Enc process
ecipher = Cipher.getInstance(key.getAlgorithm());
ecipher.init(Cipher.ENCRYPT_MODE, key, paramSpec);
String charSet = "UTF-8";
byte[] in = plainText.getBytes(charSet);
byte[] out = ecipher.doFinal(in);
String encStr = new String(Base64.getEncoder().encode(out));
return encStr;
}
/**
* @param secretKey Key used to decrypt data
* @param encryptedText encrypted text input to decrypt
* @return Returns plain text after decryption
* @throws java.security.NoSuchAlgorithmException
* @throws java.security.spec.InvalidKeySpecException
* @throws javax.crypto.NoSuchPaddingException
* @throws java.security.InvalidKeyException
* @throws java.security.InvalidAlgorithmParameterException
* @throws java.io.UnsupportedEncodingException
* @throws javax.crypto.IllegalBlockSizeException
* @throws javax.crypto.BadPaddingException
*/
public String decrypt(String secretKey, String encryptedText)
throws NoSuchAlgorithmException,
InvalidKeySpecException,
NoSuchPaddingException,
InvalidKeyException,
InvalidAlgorithmParameterException,
UnsupportedEncodingException,
IllegalBlockSizeException,
BadPaddingException,
IOException {
//Key generation for enc and desc
KeySpec keySpec = new PBEKeySpec(secretKey.toCharArray(), salt, iterationCount);
SecretKey key = SecretKeyFactory.getInstance("PBEWithMD5AndDES").generateSecret(keySpec);
// Prepare the parameter to the ciphers
AlgorithmParameterSpec paramSpec = new PBEParameterSpec(salt, iterationCount);
//Decryption process; same key will be used for decr
dcipher = Cipher.getInstance(key.getAlgorithm());
dcipher.init(Cipher.DECRYPT_MODE, key, paramSpec);
byte[] enc = Base64.getDecoder().decode(encryptedText);
byte[] utf8 = dcipher.doFinal(enc);
String charSet = "UTF-8";
String plainStr = new String(utf8, charSet);
return plainStr;
}
public static void main(String[] args) throws Exception {
CryptoUtil cryptoUtil=new CryptoUtil();
String key="ezeon8547";
String plain="This is an important message";
String enc=cryptoUtil.encrypt(key, plain);
System.out.println("Original text: "+plain);
System.out.println("Encrypted text: "+enc);
String plainAfter=cryptoUtil.decrypt(key, enc);
System.out.println("Original text after decryption: "+plainAfter);
}
}
Equivalent of String.format in jQuery
This violates DRY principle, but it's a concise solution:
var button = '<a href="{link}" class="btn">{text}</a>';
button = button.replace('{text}','Authorize on GitHub').replace('{link}', authorizeUrl);
How to delete multiple pandas (python) dataframes from memory to save RAM?
del
statement does not delete an instance, it merely deletes a name.
When you do del i
, you are deleting just the name i - but the instance is still bound to some other name, so it won't be Garbage-Collected.
If you want to release memory, your dataframes has to be Garbage-Collected, i.e. delete all references to them.
If you created your dateframes dynamically to list, then removing that list will trigger Garbage Collection.
>>> lst = [pd.DataFrame(), pd.DataFrame(), pd.DataFrame()]
>>> del lst # memory is released
If you created some variables, you have to delete them all.
>>> a, b, c = pd.DataFrame(), pd.DataFrame(), pd.DataFrame()
>>> lst = [a, b, c]
>>> del a, b, c # dfs still in list
>>> del lst # memory release now
Get IPv4 addresses from Dns.GetHostEntry()
public Form1()
{
InitializeComponent();
string myHost = System.Net.Dns.GetHostName();
string myIP = null;
for (int i = 0; i <= System.Net.Dns.GetHostEntry(myHost).AddressList.Length - 1; i++)
{
if (System.Net.Dns.GetHostEntry(myHost).AddressList[i].IsIPv6LinkLocal == false)
{
myIP = System.Net.Dns.GetHostEntry(myHost).AddressList[i].ToString();
}
}
}
Declare myIP and myHost in public Variable
and use in any function of the form.
How Big can a Python List Get?
According to the source code, the maximum size of a list is PY_SSIZE_T_MAX/sizeof(PyObject*)
.
PY_SSIZE_T_MAX
is defined in pyport.h to be ((size_t) -1)>>1
On a regular 32bit system, this is (4294967295 / 2) / 4 or 536870912.
Therefore the maximum size of a python list on a 32 bit system is 536,870,912 elements.
As long as the number of elements you have is equal or below this, all list functions should operate correctly.
ActionBar text color
Add it to the root of the action bar. I had this problem.
<style name="ActionBar" parent="@style/Theme.AppCompat.Light">
<item name="actionBarStyle">@style/Widget.Styled.ActionBar</item>
<item name="actionMenuTextColor">@color/stdDarkBlueText</item>
</style>
<style name="Widget.Styled.ActionBar" parent="@style/Widget.AppCompat.Light.ActionBar">
<item name="titleTextStyle">@style/ActionBarTitleText</item>
<item name="subtitleTextStyle">@style/ActionBarSubTitleText</item>
</style>
<style name="ActionBarTitleText" parent="@style/TextAppearance.AppCompat.Widget.ActionBar.Title">
<item name="android:textColor">@color/stdDarkBlueText</item>
<item name="android:textSize">12sp</item>
</style>
<style name="ActionBarSubTitleText" parent="@style/TextAppearance.AppCompat.Widget.ActionBar.Subtitle">
<item name="android:textColor">@color/stdDarkBlueText</item>
<item name="android:textSize">12sp</item>
</style>
actionMenuTextColor - changes text color for the action bar text, it never worked when it was part of the Widget.Styled.ActionBar
, so I had to add it to the root. Other 2 attributes change title and subtitle of an action bar.
Warning about `$HTTP_RAW_POST_DATA` being deprecated
I experienced the same issue on nginx server (DigitalOcean) - all I had to do is to log in as root
and modify the file /etc/php5/fpm/php.ini
.
To find the line with the always_populate_raw_post_data
I first run grep
:
grep -n 'always_populate_raw_post_data' php.ini
That returned the line 704
704:;always_populate_raw_post_data = -1
Then simply open php.ini
on that line with vi
editor:
vi +704 php.ini
Remove the semi colon to uncomment it and save the file :wq
Lastly reboot the server and the error went away.
How to pass variable number of arguments to printf/sprintf
You are looking for variadic functions. printf() and sprintf() are variadic functions - they can accept a variable number of arguments.
This entails basically these steps:
The first parameter must give some indication of the number of parameters that follow. So in printf(), the "format" parameter gives this indication - if you have 5 format specifiers, then it will look for 5 more arguments (for a total of 6 arguments.) The first argument could be an integer (eg "myfunction(3, a, b, c)" where "3" signifies "3 arguments)
Then loop through and retrieve each successive argument, using the va_start() etc. functions.
There are plenty of tutorials on how to do this - good luck!
How can jQuery deferred be used?
I've just used Deferred in real code. In project jQuery Terminal I have function exec that call commands defined by user (like he was entering it and pressing enter), I've added Deferreds to the API and call exec with arrays. like this:
terminal.exec('command').then(function() {
terminal.echo('command finished');
});
or
terminal.exec(['command 1', 'command 2', 'command 3']).then(function() {
terminal.echo('all commands finished');
});
the commands can run async code, and exec need to call user code in order. My first api use pair of pause/resume calls and in new API I call those automatic when user return promise. So user code can just use
return $.get('/some/url');
or
var d = new $.Deferred();
setTimeout(function() {
d.resolve("Hello Deferred"); // resolve value will be echoed
}, 500);
return d.promise();
I use code like this:
exec: function(command, silent, deferred) {
var d;
if ($.isArray(command)) {
return $.when.apply($, $.map(command, function(command) {
return self.exec(command, silent);
}));
}
// both commands executed here (resume will call Term::exec)
if (paused) {
// delay command multiple time
d = deferred || new $.Deferred();
dalyed_commands.push([command, silent, d]);
return d.promise();
} else {
// commands may return promise from user code
// it will resolve exec promise when user promise
// is resolved
var ret = commands(command, silent, true, deferred);
if (!ret) {
if (deferred) {
deferred.resolve(self);
return deferred.promise();
} else {
d = new $.Deferred();
ret = d.promise();
ret.resolve();
}
}
return ret;
}
},
dalyed_commands is used in resume function that call exec again with all dalyed_commands.
and part of the commands function (I've stripped not related parts)
function commands(command, silent, exec, deferred) {
var position = lines.length-1;
// Call user interpreter function
var result = interpreter.interpreter(command, self);
// user code can return a promise
if (result != undefined) {
// new API - auto pause/resume when using promises
self.pause();
return $.when(result).then(function(result) {
// don't echo result if user echo something
if (result && position === lines.length-1) {
display_object(result);
}
// resolve promise from exec. This will fire
// code if used terminal::exec('command').then
if (deferred) {
deferred.resolve();
}
self.resume();
});
}
// this is old API
// if command call pause - wait until resume
if (paused) {
self.bind('resume.command', function() {
// exec with resume/pause in user code
if (deferred) {
deferred.resolve();
}
self.unbind('resume.command');
});
} else {
// this should not happen
if (deferred) {
deferred.resolve();
}
}
}
display data from SQL database into php/ html table
refer to http://www.w3schools.com/php/php_mysql_select.asp .
If you are a beginner and want to learn, w3schools is a good place.
<?php
$con=mysqli_connect("localhost","root","YOUR_PHPMYADMIN_PASSWORD","hrmwaitrose");
// Check connection
if (mysqli_connect_errno())
{
echo "Failed to connect to MySQL: " . mysqli_connect_error();
}
$result = mysqli_query($con,"SELECT * FROM employee");
while($row = mysqli_fetch_array($result))
{
echo $row['FirstName'] . " " . $row['LastName']; //these are the fields that you have stored in your database table employee
echo "<br />";
}
mysqli_close($con);
?>
You can similarly echo
it inside your table
<?php
echo "<table>";
while($row = mysqli_fetch_array($result))
{
echo "<tr><td>" . $row['FirstName'] . "</td><td> " . $row['LastName'] . "</td></tr>"; //these are the fields that you have stored in your database table employee
}
echo "</table>";
mysqli_close($con);
?>
How to pass objects to functions in C++?
There are three methods of passing an object to a function as a parameter:
- Pass by reference
- pass by value
- adding constant in parameter
Go through the following example:
class Sample
{
public:
int *ptr;
int mVar;
Sample(int i)
{
mVar = 4;
ptr = new int(i);
}
~Sample()
{
delete ptr;
}
void PrintVal()
{
cout << "The value of the pointer is " << *ptr << endl
<< "The value of the variable is " << mVar;
}
};
void SomeFunc(Sample x)
{
cout << "Say i am in someFunc " << endl;
}
int main()
{
Sample s1= 10;
SomeFunc(s1);
s1.PrintVal();
char ch;
cin >> ch;
}
Output:
Say i am in someFunc
The value of the pointer is -17891602
The value of the variable is 4
What's the difference between display:inline-flex and display:flex?
OK, I know at first might be a bit confusing, but display
is talking about the parent element, so means when we say: display: flex;
, it's about the element and when we say display:inline-flex;
, is also making the element itself inline
...
It's like make a div
inline or block, run the snippet below and you can see how display flex
breaks down to next line:
_x000D_
_x000D_
.inline-flex {_x000D_
display: inline-flex;_x000D_
}_x000D_
_x000D_
.flex {_x000D_
display: flex;_x000D_
}_x000D_
_x000D_
p {_x000D_
color: red;_x000D_
}
_x000D_
<body>_x000D_
<p>Display Inline Flex</p>_x000D_
<div class="inline-flex">_x000D_
<header>header</header>_x000D_
<nav>nav</nav>_x000D_
<aside>aside</aside>_x000D_
<main>main</main>_x000D_
<footer>footer</footer>_x000D_
</div>_x000D_
_x000D_
<div class="inline-flex">_x000D_
<header>header</header>_x000D_
<nav>nav</nav>_x000D_
<aside>aside</aside>_x000D_
<main>main</main>_x000D_
<footer>footer</footer>_x000D_
</div>_x000D_
_x000D_
<p>Display Flex</p>_x000D_
<div class="flex">_x000D_
<header>header</header>_x000D_
<nav>nav</nav>_x000D_
<aside>aside</aside>_x000D_
<main>main</main>_x000D_
<footer>footer</footer>_x000D_
</div>_x000D_
_x000D_
<div class="flex">_x000D_
<header>header</header>_x000D_
<nav>nav</nav>_x000D_
<aside>aside</aside>_x000D_
<main>main</main>_x000D_
<footer>footer</footer>_x000D_
</div>_x000D_
</body>
_x000D_
_x000D_
_x000D_
Also quickly create the image below to show the difference at a glance:
![display flex vs display inline-flex](https://i.stack.imgur.com/mns2H.jpg)
Removing certain characters from a string in R
This should work
gsub('\u009c','','\u009cYes yes for ever for ever the boys ')
"Yes yes for ever for ever the boys "
Here 009c is the hexadecimal number of unicode. You must always specify 4 hexadecimal digits.
If you have many , one solution is to separate them by a pipe:
gsub('\u009c|\u00F0','','\u009cYes yes \u00F0for ever for ever the boys and the girls')
"Yes yes for ever for ever the boys and the girls"
Column "invalid in the select list because it is not contained in either an aggregate function or the GROUP BY clause"
The consequence of this is that you may need a rather insane-looking query, e. g.,
SELECT [dbo].[tblTimeSheetExportFiles].[lngRecordID] AS lngRecordID
,[dbo].[tblTimeSheetExportFiles].[vcrSourceWorkbookName] AS vcrSourceWorkbookName
,[dbo].[tblTimeSheetExportFiles].[vcrImportFileName] AS vcrImportFileName
,[dbo].[tblTimeSheetExportFiles].[dtmLastWriteTime] AS dtmLastWriteTime
,[dbo].[tblTimeSheetExportFiles].[lngNRecords] AS lngNRecords
,[dbo].[tblTimeSheetExportFiles].[lngSizeOnDisk] AS lngSizeOnDisk
,[dbo].[tblTimeSheetExportFiles].[lngLastIdentity] AS lngLastIdentity
,[dbo].[tblTimeSheetExportFiles].[dtmImportCompletedTime] AS dtmImportCompletedTime
,MIN ( [tblTimeRecords].[dtmActivity_Date] ) AS dtmPeriodFirstWorkDate
,MAX ( [tblTimeRecords].[dtmActivity_Date] ) AS dtmPeriodLastWorkDate
,SUM ( [tblTimeRecords].[decMan_Hours_Actual] ) AS decHoursWorked
,SUM ( [tblTimeRecords].[decAdjusted_Hours] ) AS decHoursBilled
FROM [dbo].[tblTimeSheetExportFiles]
LEFT JOIN [dbo].[tblTimeRecords]
ON [dbo].[tblTimeSheetExportFiles].[lngRecordID] = [dbo].[tblTimeRecords].[lngTimeSheetExportFile]
GROUP BY [dbo].[tblTimeSheetExportFiles].[lngRecordID]
,[dbo].[tblTimeSheetExportFiles].[vcrSourceWorkbookName]
,[dbo].[tblTimeSheetExportFiles].[vcrImportFileName]
,[dbo].[tblTimeSheetExportFiles].[dtmLastWriteTime]
,[dbo].[tblTimeSheetExportFiles].[lngNRecords]
,[dbo].[tblTimeSheetExportFiles].[lngSizeOnDisk]
,[dbo].[tblTimeSheetExportFiles].[lngLastIdentity]
,[dbo].[tblTimeSheetExportFiles].[dtmImportCompletedTime]
Since the primary table is a summary table, its primary key handles the only grouping or ordering that is truly necessary. Hence, the GROUP BY clause exists solely to satisfy the query parser.
Using SQL LIKE and IN together
I tried another way
Say the table has values
1 M510
2 M615
3 M515
4 M612
5 M510MM
6 M615NN
7 M515OO
8 M612PP
9 A
10 B
11 C
12 D
Here cols 1 to 8 are valid while the rest of them are invalid
SELECT COL_VAL
FROM SO_LIKE_TABLE SLT
WHERE (SELECT DECODE(SUM(CASE
WHEN INSTR(SLT.COL_VAL, COLUMN_VALUE) > 0 THEN
1
ELSE
0
END),
0,
'FALSE',
'TRUE')
FROM TABLE(SYS.DBMS_DEBUG_VC2COLl('M510', 'M615', 'M515', 'M612'))) =
'TRUE'
What I have done is using the INSTR function, I have tried to find is the value in table matches with any of the values as input. In case it does, it will return it's index, i.e. greater than ZERO. In case the table's value does not match with any of the input, then it will return ZERO. This index I have added up, to indicate successful match.
It seems to be working.
Hope it helps.
How do I change the default location for Git Bash on Windows?
Git bash is used to play with bash commands. So I use bash method itself in windows Git bash
Edit your .bash_profile
(create it if you doesnot have one - see below how to create). Enter the following lines.
Add these lines to the file
alias ws="cd /d/workspace/"
ws
My .bash_profile looks like this
Smilyface@SmilingMachine /d/workspace
$ cat ~/.bash_profile
alias ws="cd /d/workspace/"
ws
How to create a new .bash_profile ?
touch ~/.bash_profile
OR write into the file directly
vi ~/.bash_profile
Simple, aha !
How to Implement DOM Data Binding in JavaScript
Bind any html input
<input id="element-to-bind" type="text">
define two functions:
function bindValue(objectToBind) {
var elemToBind = document.getElementById(objectToBind.id)
elemToBind.addEventListener("change", function() {
objectToBind.value = this.value;
})
}
function proxify(id) {
var handler = {
set: function(target, key, value, receiver) {
target[key] = value;
document.getElementById(target.id).value = value;
return Reflect.set(target, key, value);
},
}
return new Proxy({id: id}, handler);
}
use the functions:
var myObject = proxify('element-to-bind')
bindValue(myObject);
100% width Twitter Bootstrap 3 template
Using Bootstrap 3.3.5 and .container-fluid
, this is how I get full width with no gutters or horizontal scrolling on mobile. Note that .container-fluid
was re-introduced in 3.1.
Full width on mobile/tablet, 1/4 screen on desktop
<div class="container-fluid"> <!-- Adds 15px left/right padding -->
<div class="row"> <!-- Adds -15px left/right margins -->
<div class="col-md-4 col-md-offset-4" style="padding-left: 0, padding-right: 0"> <!-- col classes adds 15px padding, so remove the same amount -->
<!-- Full-width for mobile -->
<!-- 1/4 screen width for desktop -->
</div>
</div>
</div>
Full width on all resolutions (mobile, table, desktop)
<div class="container-fluid"> <!-- Adds 15px left/right padding -->
<div class="row"> <!-- Adds -15px left/right margins -->
<div>
<!-- Full-width content -->
</div>
</div>
</div>
Spring JDBC Template for calling Stored Procedures
There are a number of ways to call stored procedures in Spring.
If you use CallableStatementCreator
to declare parameters, you will be using Java's standard interface of CallableStatement
, i.e register out parameters and set them separately. Using SqlParameter
abstraction will make your code cleaner.
I recommend you looking at SimpleJdbcCall
. It may be used like this:
SimpleJdbcCall jdbcCall = new SimpleJdbcCall(jdbcTemplate)
.withSchemaName(schema)
.withCatalogName(package)
.withProcedureName(procedure)();
...
jdbcCall.addDeclaredParameter(new SqlParameter(paramName, OracleTypes.NUMBER));
...
jdbcCall.execute(callParams);
For simple procedures you may use jdbcTemplate
's update
method:
jdbcTemplate.update("call SOME_PROC (?, ?)", param1, param2);
Removing leading and trailing spaces from a string
Here is how you can do it:
std::string & trim(std::string & str)
{
return ltrim(rtrim(str));
}
And the supportive functions are implemeted as:
std::string & ltrim(std::string & str)
{
auto it2 = std::find_if( str.begin() , str.end() , [](char ch){ return !std::isspace<char>(ch , std::locale::classic() ) ; } );
str.erase( str.begin() , it2);
return str;
}
std::string & rtrim(std::string & str)
{
auto it1 = std::find_if( str.rbegin() , str.rend() , [](char ch){ return !std::isspace<char>(ch , std::locale::classic() ) ; } );
str.erase( it1.base() , str.end() );
return str;
}
And once you've all these in place, you can write this as well:
std::string trim_copy(std::string const & str)
{
auto s = str;
return ltrim(rtrim(s));
}
Try this
pop/remove items out of a python tuple
say you have a dict
with tuples as keys, e.g: labels = {(1,2,0): 'label_1'}
you can modify the elements of the tuple keys as follows:
formatted_labels = {(elem[0],elem[1]):labels[elem] for elem in labels}
Here, we ignore the last elements.
/exclude in xcopy just for a file type
The /EXCLUDE:
argument expects a file containing a list of excluded files.
So create a file called excludedfileslist.txt
containing:
.cs\
Then a command like this:
xcopy /r /d /i /s /y /exclude:excludedfileslist.txt C:\dev\apan C:\web\apan
Alternatively you could use Robocopy, but would require installing / copying a robocopy.exe
to the machines.
Update
An anonymous comment edit which simply stated "This Solution exclude also css file!"
This is true creating a excludedfileslist.txt
file contain just:
.cs
(note no backslash on the end)
Will also exclude all of the following:
file1.cs
file2.css
dir1.cs\file3.txt
dir2\anyfile.cs.something.txt
Sometimes people don't read or understand the XCOPY command's help, here is an item I would like to highlight:
Using /exclude
- List each string in a separate line in each file. If any of the listed strings match any part of the absolute path of the file to be copied, that file is then excluded from the copying process. For example, if you specify the string "\Obj\", you exclude all files underneath the Obj directory. If you specify the string ".obj", you exclude all files with the .obj extension.
As the example states it excludes "all files with the .obj extension" but it doesn't state that it also excludes files or directories named file1.obj.tmp
or dir.obj.output\example2.txt
.
There is a way around .css
files being excluded also, change the excludedfileslist.txt
file to contain just:
.cs\
(note the backslash on the end).
Here is a complete test sequence for your reference:
C:\test1>ver
Microsoft Windows [Version 6.1.7601]
C:\test1>md src
C:\test1>md dst
C:\test1>md src\dir1
C:\test1>md src\dir2.cs
C:\test1>echo "file contents" > src\file1.cs
C:\test1>echo "file contents" > src\file2.css
C:\test1>echo "file contents" > src\dir1\file3.txt
C:\test1>echo "file contents" > src\dir1\file4.cs.txt
C:\test1>echo "file contents" > src\dir2.cs\file5.txt
C:\test1>xcopy /r /i /s /y .\src .\dst
.\src\file1.cs
.\src\file2.css
.\src\dir1\file3.txt
.\src\dir1\file4.cs.txt
.\src\dir2.cs\file5.txt
5 File(s) copied
C:\test1>echo .cs > excludedfileslist.txt
C:\test1>xcopy /r /i /s /y /exclude:excludedfileslist.txt .\src .\dst
.\src\dir1\file3.txt
1 File(s) copied
C:\test1>echo .cs\ > excludedfileslist.txt
C:\test1>xcopy /r /i /s /y /exclude:excludedfileslist.txt .\src .\dst
.\src\file2.css
.\src\dir1\file3.txt
.\src\dir1\file4.cs.txt
3 File(s) copied
This test was completed on a Windows 7 command line and retested on Windows 10 "10.0.14393".
Note that the last example does exclude .\src\dir2.cs\file5.txt
which may or may not be unexpected for you.
Apply function to each element of a list
I think you mean to use map
instead of filter
:
>>> from string import upper
>>> mylis=['this is test', 'another test']
>>> map(upper, mylis)
['THIS IS TEST', 'ANOTHER TEST']
Even simpler, you could use str.upper
instead of importing from string
(thanks to @alecxe):
>>> map(str.upper, mylis)
['THIS IS TEST', 'ANOTHER TEST']
In Python 2.x, map
constructs a new list by applying a given function to every element in a list. filter
constructs a new list by restricting to elements that evaluate to True
with a given function.
In Python 3.x, map
and filter
construct iterators instead of lists, so if you are using Python 3.x and require a list the list comprehension approach would be better suited.
ERROR 1452: Cannot add or update a child row: a foreign key constraint fails
I know this thread is long already but when I ran a laravel seeding for category tables it created some strange ids which were 1, 11, 21, 31 which caused me error as I tried to reference it in another another table using ids like 1, 2, 3 ... the whole day until I checked the database up manually,
So sometimes go look up the database table to ensure the foreign data actually exist properly.
Cheers
Asp Net Web API 2.1 get client IP address
I think this is the most clear solution, using an extension method:
public static class HttpRequestMessageExtensions
{
private const string HttpContext = "MS_HttpContext";
private const string RemoteEndpointMessage = "System.ServiceModel.Channels.RemoteEndpointMessageProperty";
public static string GetClientIpAddress(this HttpRequestMessage request)
{
if (request.Properties.ContainsKey(HttpContext))
{
dynamic ctx = request.Properties[HttpContext];
if (ctx != null)
{
return ctx.Request.UserHostAddress;
}
}
if (request.Properties.ContainsKey(RemoteEndpointMessage))
{
dynamic remoteEndpoint = request.Properties[RemoteEndpointMessage];
if (remoteEndpoint != null)
{
return remoteEndpoint.Address;
}
}
return null;
}
}
So just use it like:
var ipAddress = request.GetClientIpAddress();
We use this in our projects.
Source/Reference: Retrieving the client’s IP address in ASP.NET Web API
Sorting an ArrayList of objects using a custom sorting order
Here's a tutorial about ordering objects:
Although I will give some examples, I would recommend to read it anyway.
There are various way to sort an ArrayList
. If you want to define a natural (default) ordering, then you need to let Contact
implement Comparable
. Assuming that you want to sort by default on name
, then do (nullchecks omitted for simplicity):
public class Contact implements Comparable<Contact> {
private String name;
private String phone;
private Address address;
@Override
public int compareTo(Contact other) {
return name.compareTo(other.name);
}
// Add/generate getters/setters and other boilerplate.
}
so that you can just do
List<Contact> contacts = new ArrayList<Contact>();
// Fill it.
Collections.sort(contacts);
If you want to define an external controllable ordering (which overrides the natural ordering), then you need to create a Comparator
:
List<Contact> contacts = new ArrayList<Contact>();
// Fill it.
// Now sort by address instead of name (default).
Collections.sort(contacts, new Comparator<Contact>() {
public int compare(Contact one, Contact other) {
return one.getAddress().compareTo(other.getAddress());
}
});
You can even define the Comparator
s in the Contact
itself so that you can reuse them instead of recreating them everytime:
public class Contact {
private String name;
private String phone;
private Address address;
// ...
public static Comparator<Contact> COMPARE_BY_PHONE = new Comparator<Contact>() {
public int compare(Contact one, Contact other) {
return one.phone.compareTo(other.phone);
}
};
public static Comparator<Contact> COMPARE_BY_ADDRESS = new Comparator<Contact>() {
public int compare(Contact one, Contact other) {
return one.address.compareTo(other.address);
}
};
}
which can be used as follows:
List<Contact> contacts = new ArrayList<Contact>();
// Fill it.
// Sort by address.
Collections.sort(contacts, Contact.COMPARE_BY_ADDRESS);
// Sort later by phone.
Collections.sort(contacts, Contact.COMPARE_BY_PHONE);
And to cream the top off, you could consider to use a generic javabean comparator:
public class BeanComparator implements Comparator<Object> {
private String getter;
public BeanComparator(String field) {
this.getter = "get" + field.substring(0, 1).toUpperCase() + field.substring(1);
}
public int compare(Object o1, Object o2) {
try {
if (o1 != null && o2 != null) {
o1 = o1.getClass().getMethod(getter, new Class[0]).invoke(o1, new Object[0]);
o2 = o2.getClass().getMethod(getter, new Class[0]).invoke(o2, new Object[0]);
}
} catch (Exception e) {
// If this exception occurs, then it is usually a fault of the developer.
throw new RuntimeException("Cannot compare " + o1 + " with " + o2 + " on " + getter, e);
}
return (o1 == null) ? -1 : ((o2 == null) ? 1 : ((Comparable<Object>) o1).compareTo(o2));
}
}
which you can use as follows:
// Sort on "phone" field of the Contact bean.
Collections.sort(contacts, new BeanComparator("phone"));
(as you see in the code, possibly null fields are already covered to avoid NPE's during sort)
How do I repair an InnoDB table?
The following solution was inspired by Sandro's tip above.
Warning: while it worked for me, but I cannot tell if it will work for you.
My problem was the following: reading some specific rows from a table (let's call this table broken
) would crash MySQL. Even SELECT COUNT(*) FROM broken
would kill it. I hope you have a PRIMARY KEY
on this table (in the following sample, it's id
).
- Make sure you have a backup or snapshot of the broken MySQL server (just in case you want to go back to step 1 and try something else!)
CREATE TABLE broken_repair LIKE broken;
INSERT broken_repair SELECT * FROM broken WHERE id NOT IN (SELECT id FROM broken_repair) LIMIT 1;
- Repeat step 3 until it crashes the DB (you can use
LIMIT 100000
and then use lower values, until using LIMIT 1
crashes the DB).
- See if you have everything (you can compare
SELECT MAX(id) FROM broken
with the number of rows in broken_repair
).
- At this point, I apparently had all my rows (except those which were probably savagely truncated by InnoDB). If you miss some rows, you could try adding an
OFFSET
to the LIMIT
.
Good luck!
How to get the Android Emulator's IP address?
Use this method you will be getting 100% correct ip address for your android emulator
To get the ip address of yoor emulator
Go to adb shell and type this command
adb shell
ifconfig eth0
![enter image description here](https://i.stack.imgur.com/jlioW.jpg)
After running this command I am getting
IP : 10.0.2.15
Mask : 255.255.255.0
Which works for me . I am also working for an networking application.
How can I login to a website with Python?
Maybe you want to use twill. It's quite easy to use and should be able to do what you want.
It will look like the following:
from twill.commands import *
go('http://example.org')
fv("1", "email-email", "blabla.com")
fv("1", "password-clear", "testpass")
submit('0')
You can use showforms()
to list all forms once you used go…
to browse to the site you want to login. Just try it from the python interpreter.
How to change the color of a button?
You can change the value in the XML like this:
<Button
android:background="#FFFFFF"
../>
Here, you can add any other color, from the resources or hex.
Similarly, you can also change these values form the code like this:
demoButton.setBackgroundColor(Color.WHITE);
Another easy way is to make a drawable, customize the corners and shape according to your preference and set the background color and stroke of the drawable.
For eg.
button_background.xml
<?xml version="1.0" encoding="UTF-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android">
<stroke android:width="2dp" android:color="#ff207d94" />
<corners android:radius="5dp" />
<solid android:color="#FFFFFF" />
</shape>
And then set this shape as the background of your button.
<Button
android:background="@drawable/button_background.xml"
../>
Hope this helps, good luck!
Best way to parse command-line parameters?
freecli
package freecli
package examples
package command
import java.io.File
import freecli.core.all._
import freecli.config.all._
import freecli.command.all._
object Git extends App {
case class CommitConfig(all: Boolean, message: String)
val commitCommand =
cmd("commit") {
takesG[CommitConfig] {
O.help --"help" ::
flag --"all" -'a' -~ des("Add changes from all known files") ::
O.string -'m' -~ req -~ des("Commit message")
} ::
runs[CommitConfig] { config =>
if (config.all) {
println(s"Commited all ${config.message}!")
} else {
println(s"Commited ${config.message}!")
}
}
}
val rmCommand =
cmd("rm") {
takesG[File] {
O.help --"help" ::
file -~ des("File to remove from git")
} ::
runs[File] { f =>
println(s"Removed file ${f.getAbsolutePath} from git")
}
}
val remoteCommand =
cmd("remote") {
takes(O.help --"help") ::
cmd("add") {
takesT {
O.help --"help" ::
string -~ des("Remote name") ::
string -~ des("Remote url")
} ::
runs[(String, String)] {
case (s, u) => println(s"Remote $s $u added")
}
} ::
cmd("rm") {
takesG[String] {
O.help --"help" ::
string -~ des("Remote name")
} ::
runs[String] { s =>
println(s"Remote $s removed")
}
}
}
val git =
cmd("git", des("Version control system")) {
takes(help --"help" :: version --"version" -~ value("v1.0")) ::
commitCommand ::
rmCommand ::
remoteCommand
}
val res = runCommandOrFail(git)(args).run
}
This will generate the following usage:
Usage
How to create a date and time picker in Android?
![combined DatePicker and TimePicker in DialogFragment for Android](https://i.stack.imgur.com/1XQg5.png)
I created a library to do this. It also has customizable colors!
It's very simple to use.
First you create a listener:
private SlideDateTimeListener listener = new SlideDateTimeListener() {
@Override
public void onDateTimeSet(Date date)
{
// Do something with the date. This Date object contains
// the date and time that the user has selected.
}
@Override
public void onDateTimeCancel()
{
// Overriding onDateTimeCancel() is optional.
}
};
Then you create and show the dialog:
new SlideDateTimePicker.Builder(getSupportFragmentManager())
.setListener(listener)
.setInitialDate(new Date())
.build()
.show();
I hope you find it useful.
C library function to perform sort
While not in the standard library exactly, https://github.com/swenson/sort has just two header files you can include to get access to a wide range of incredibly fast sorting routings, like so:
#define SORT_NAME int64
#define SORT_TYPE int64_t
#define SORT_CMP(x, y) ((x) - (y))
#include "sort.h"
/* You now have access to int64_quick_sort, int64_tim_sort, etc., e.g., */
int64_quick_sort(arr, 128); /* Assumes you have some int *arr or int arr[128]; */
This should be at least twice as fast as the standard library qsort
, since it doesn't use function pointers, and has many other sorting algorithm options to choose from.
It's in C89, so should work in basically every C compiler.
Should I use px or rem value units in my CSS?
Yes. Or, rather, no.
Er, I mean, it doesn't matter. Use the one that makes sense for your particular project. PX and EM or both equally valid but will behave a bit different depending on your overall page's CSS architecture.
UPDATE:
To clarify, I'm stating that usually it likely doesn't matter which you use. At times, you may specifically want to choose one over the other. EMs are nice if you can start from scratch and want to use a base font size and make everything relative to that.
PXs are often needed when you're retrofitting a redesign onto an existing code base and need the specificity of px to prevent bad nesting issues.
Can we instantiate an abstract class?
No, we can't create the object of abstract class, but create the reference variable of the abstract class. The reference variable is used to refer to the objects of derived classes (Sub classes of Abstract class)
Here is the example that illustrates this concept
abstract class Figure {
double dim1;
double dim2;
Figure(double a, double b) {
dim1 = a;
dim2 = b;
}
// area is now an abstract method
abstract double area();
}
class Rectangle extends Figure {
Rectangle(double a, double b) {
super(a, b);
}
// override area for rectangle
double area() {
System.out.println("Inside Area for Rectangle.");
return dim1 * dim2;
}
}
class Triangle extends Figure {
Triangle(double a, double b) {
super(a, b);
}
// override area for right triangle
double area() {
System.out.println("Inside Area for Triangle.");
return dim1 * dim2 / 2;
}
}
class AbstractAreas {
public static void main(String args[]) {
// Figure f = new Figure(10, 10); // illegal now
Rectangle r = new Rectangle(9, 5);
Triangle t = new Triangle(10, 8);
Figure figref; // this is OK, no object is created
figref = r;
System.out.println("Area is " + figref.area());
figref = t;
System.out.println("Area is " + figref.area());
}
}
Here we see that we cannot create the object of type Figure but we can create a reference variable of type Figure. Here we created a reference variable of type Figure and Figure Class reference variable is used to refer to the objects of Class Rectangle and Triangle.
Has anyone gotten HTML emails working with Twitter Bootstrap?
The trick here is that you don't want to include the whole bootstrap. The issue is that email clients will ignore the media queries and process all the print styles which have a lot of !important statements.
Instead, you need to only include the specific parts of bootstrap that you need. My email.css.scss file looks like this:
@import "bootstrap-sprockets";
@import "bootstrap/variables";
@import "bootstrap/mixins";
@import "bootstrap/scaffolding";
@import "bootstrap/type";
@import "bootstrap/buttons";
@import "bootstrap/alerts";
@import 'bootstrap/normalize';
@import 'bootstrap/tables';
Center icon in a div - horizontally and vertically
Horizontal centering is as easy as:
text-align: center
Vertical centering when the container is a known height:
height: 100px;
line-height: 100px;
vertical-align: middle
Vertical centering when the container isn't a known height AND you can set the image in the background:
background: url(someimage) no-repeat center center;
Split page vertically using CSS
I guess your elements on the page messes up because you don't clear out your floats, check this out
Demo
HTML
<div class="wrap">
<div class="floatleft"></div>
<div class="floatright"></div>
<div style="clear: both;"></div>
</div>
CSS
.wrap {
width: 100%;
}
.floatleft {
float:left;
width: 80%;
background-color: #ff0000;
height: 400px;
}
.floatright {
float: right;
background-color: #00ff00;
height: 400px;
width: 20%;
}
Enable PHP Apache2
If anyone gets
ERROR: Module phpX.X does not exist!
just install the module for your current php version:
apt-get install libapache2-mod-phpX.X
.datepicker('setdate') issues, in jQuery
As Scobal's post implies, the datepicker is looking for a Date object - not just a string! So, to modify your example code to do what you want:
var queryDate = new Date('2009/11/01'); // Dashes won't work
$('#datePicker').datepicker('setDate', queryDate);
Prevent text selection after double click
function clearSelection() {
if(document.selection && document.selection.empty) {
document.selection.empty();
} else if(window.getSelection) {
var sel = window.getSelection();
sel.removeAllRanges();
}
}
You can also apply these styles to the span for all non-IE browsers and IE10:
span.no_selection {
user-select: none; /* standard syntax */
-webkit-user-select: none; /* webkit (safari, chrome) browsers */
-moz-user-select: none; /* mozilla browsers */
-khtml-user-select: none; /* webkit (konqueror) browsers */
-ms-user-select: none; /* IE10+ */
}
fix java.net.SocketTimeoutException: Read timed out
Here are few pointers/suggestions for investigation
- I see that every time you vote, you call
vote
method which creates a fresh HTTP connection.
- This might be a problem. I would suggest to use a single
HttpClient
instance to post to the server. This way it wont create too many connections from the client side.
- At the end of everything,
HttpClient
needs to be shut and hence call httpclient.getConnectionManager().shutdown();
to release the resources used by the connections.
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
How to use breakpoints in Eclipse
To put breakpoints in your code, double click in the left margin on the line you want execution to stop on. You may alternatively put your cursor in this line and then press Shift+Ctrl+B.
To control execution use the Step Into, Step Over and Step Return buttons. They have the shortcuts F5, F6 and F7 respectively.
To allow execution to continue normally or until it hits the next breakpoint, hit the Resume button or F8.
What are the differences between a pointer variable and a reference variable in C++?
This program might help in comprehending the answer of the question. This is a simple program of a reference "j" and a pointer "ptr" pointing to variable "x".
#include<iostream>
using namespace std;
int main()
{
int *ptr=0, x=9; // pointer and variable declaration
ptr=&x; // pointer to variable "x"
int & j=x; // reference declaration; reference to variable "x"
cout << "x=" << x << endl;
cout << "&x=" << &x << endl;
cout << "j=" << j << endl;
cout << "&j=" << &j << endl;
cout << "*ptr=" << *ptr << endl;
cout << "ptr=" << ptr << endl;
cout << "&ptr=" << &ptr << endl;
getch();
}
Run the program and have a look at the output and you'll understand.
Also, spare 10 minutes and watch this video: https://www.youtube.com/watch?v=rlJrrGV0iOg
Codeigniter LIKE with wildcard(%)
For Full like you can user :
$this->db->like('title',$query);
For %$query you can use
$this->db->like('title', $query, 'before');
and for $query% you can use
$this->db->like('title', $query, 'after');
Ignore .classpath and .project from Git
The git solution for such scenarios is setting SKIP-WORKTREE BIT. Run only the following command:
git update-index --skip-worktree .classpath .gitignore
It is used when you want git to ignore changes of files that are already managed by git and exist on the index. This is a common use case for config files.
Running git rm --cached
doesn't work for the scenario mentioned in the question. If I simplify the question, it says:
How to have .classpath
and .project
on the repo while each one can
change it locally and git ignores this change?
As I commented under the accepted answer, the drawback of git rm --cached
is that it causes a change in the index, so you need to commit the change and then push it to the remote repository. As a result, .classpath
and .project
won't be available on the repo while the PO wants them to be there so anyone that clones the repo for the first time, they can use it.
What is SKIP-WORKTREE BIT?
Based on git documentaion:
Skip-worktree bit can be defined in one (long) sentence: When reading an entry, if it is marked as skip-worktree, then Git pretends its working directory version is up to date and read the index version instead.
Although this bit looks similar to assume-unchanged bit, its goal is different from assume-unchanged bit’s. Skip-worktree also takes precedence over assume-unchanged bit when both are set.
More details is available here.
What USB driver should we use for the Nexus 5?
Are you sure it's a driver problem? A device that isn't detected probably has a hardware or firmware problem. If it isn't detected, you won't hear the USB device detected chime. It might not be serious, e.g. some "USB" cables are really only charging cables. Try a USB cable that you know works for data, e.g. the one that came with the phone or one you use for connecting an external hard drive.
Decode HTML entities in Python string?
You can use replace_entities from w3lib.html library
In [202]: from w3lib.html import replace_entities
In [203]: replace_entities("£682m")
Out[203]: u'\xa3682m'
In [204]: print replace_entities("£682m")
£682m
What do raw.githubusercontent.com URLs represent?
raw.githubusercontent.com/username/repo-name/branch-name/path
Replace username
with the username of the user that created the repo.
Replace repo-name
with the name of the repo.
Replace branch-name
with the name of the branch.
Replace path
with the path to the file.
To reverse to go to GitHub.com:
GitHub.com/username/repo-name/directory-path/blob/branch-name/filename
Changing background color of selected cell?
Works for me
UIView *customColorView = [[UIView alloc] init];
customColorView.backgroundColor = [UIColor colorWithRed:180/255.0
green:138/255.0
blue:171/255.0
alpha:0.5];
cell.selectedBackgroundView = customColorView;
NSString with \n or line break
Line breaks character for NSString is \r
correct way to use [NSString StringWithFormat:@"%@\r%@",string1,string2];
\r ----> carriage return
RGB to hex and hex to RGB
Instead of copy'n'pasting snippets found here and there, I'd recommend to use a well tested and maintained library: Colors.js (available for node.js and browser). It's just 7 KB (minified, gzipped even less).
How to stop line breaking in vim
If, like me, you're running gVim on Windows then your .vimrc file may be sourcing another 'example' Vimscript file that automatically sets textwidth
(in my case to 78
) for text files.
My answer to a similar question as this one – How to stop gVim wrapping text at column 80 – on the Vi and Vim Stack Exchange site:
In my case, Vitor's comment suggested I run the following:
:verbose set tw?
Doing so gave me the following output:
textwidth=78
Last set from C:\Program Files (x86)\Vim\vim74\vimrc_example.vim
In vimrc_example.vim, I found the relevant lines:
" Only do this part when compiled with support for autocommands.
if has("autocmd")
...
" For all text files set 'textwidth' to 78 characters.
autocmd FileType text setlocal textwidth=78
...
And I found that my .vimrc is sourcing that file:
source $VIMRUNTIME/vimrc_example.vim
In my case, I don't want textwidth
to be set for any files, so I just commented out the relevant line in vimrc_example.vim.
Inserting multiple rows in mysql
Here is a PHP solution ready for use with a n:m (many-to-many relationship) table :
// get data
$table_1 = get_table_1_rows();
$table_2_fk_id = 123;
// prepare first part of the query (before values)
$query = "INSERT INTO `table` (
`table_1_fk_id`,
`table_2_fk_id`,
`insert_date`
) VALUES ";
//loop the table 1 to get all foreign keys and put it in array
foreach($table_1 as $row) {
$query_values[] = "(".$row["table_1_pk_id"].", $table_2_fk_id, NOW())";
}
// Implode the query values array with a coma and execute the query.
$db->query($query . implode(',',$query_values));
How to compare pointers?
It depends on the types of the values, and the way that operators happen to have been defined. For example, string comparison is by value, not by address. But char * is by address normally (I think).
A big trap for the unwary. There is no guaranteed pointer comparison operator, but
(void *)a == (void *)b
is probably fairly safe.
Update some specific field of an entity in android Room
I think you don't need to update only some specific field.
Just update whole data.
@Update query
It is a given query basically. No need to make some new query.
@Dao
interface MemoDao {
@Insert
suspend fun insert(memo: Memo)
@Delete
suspend fun delete(memo: Memo)
@Update
suspend fun update(memo: Memo)
}
Memo.class
@Entity
data class Memo (
@PrimaryKey(autoGenerate = true) val id: Int,
@ColumnInfo(name = "title") val title: String?,
@ColumnInfo(name = "content") val content: String?,
@ColumnInfo(name = "photo") val photo: List<ByteArray>?
)
Only thing you need to know is 'id'. For instance, if you want to update only 'title', you can reuse 'content' and 'photo' from already inserted data.
In real code, use like this
val memo = Memo(id, title, content, byteArrayList)
memoViewModel.update(memo)
Tool to compare directories (Windows 7)
The tool that richardtz suggests is excellent.
Another one that is amazing and comes with a 30 day free trial is Araxis Merge. This one does a 3 way merge and is much more feature complete than winmerge, but it is a commercial product.
You might also like to check out Scott Hanselman's developer tool list, which mentions a couple more in addition to winmerge
How do I access store state in React Redux?
You should create separate component, which will be listening to state changes and updating on every state change:
import store from '../reducers/store';
class Items extends Component {
constructor(props) {
super(props);
this.state = {
items: [],
};
store.subscribe(() => {
// When state will be updated(in our case, when items will be fetched),
// we will update local component state and force component to rerender
// with new data.
this.setState({
items: store.getState().items;
});
});
}
render() {
return (
<div>
{this.state.items.map((item) => <p> {item.title} </p> )}
</div>
);
}
};
render(<Items />, document.getElementById('app'));
What exactly is std::atomic?
Each instantiation and full specialization of std::atomic<> represents a type that different threads can simultaneously operate on (their instances), without raising undefined behavior:
Objects of atomic types are the only C++ objects that are free from data races; that is, if one thread writes to an atomic object while another thread reads from it, the behavior is well-defined.
In addition, accesses to atomic objects may establish inter-thread synchronization and order non-atomic memory accesses as specified by std::memory_order
.
std::atomic<>
wraps operations that, in pre-C++ 11 times, had to be performed using (for example) interlocked functions with MSVC or atomic bultins in case of GCC.
Also, std::atomic<>
gives you more control by allowing various memory orders that specify synchronization and ordering constraints. If you want to read more about C++ 11 atomics and memory model, these links may be useful:
Note that, for typical use cases, you would probably use overloaded arithmetic operators or another set of them:
std::atomic<long> value(0);
value++; //This is an atomic op
value += 5; //And so is this
Because operator syntax does not allow you to specify the memory order, these operations will be performed with std::memory_order_seq_cst
, as this is the default order for all atomic operations in C++ 11. It guarantees sequential consistency (total global ordering) between all atomic operations.
In some cases, however, this may not be required (and nothing comes for free), so you may want to use more explicit form:
std::atomic<long> value {0};
value.fetch_add(1, std::memory_order_relaxed); // Atomic, but there are no synchronization or ordering constraints
value.fetch_add(5, std::memory_order_release); // Atomic, performs 'release' operation
Now, your example:
a = a + 12;
will not evaluate to a single atomic op: it will result in a.load()
(which is atomic itself), then addition between this value and 12
and a.store()
(also atomic) of final result. As I noted earlier, std::memory_order_seq_cst
will be used here.
However, if you write a += 12
, it will be an atomic operation (as I noted before) and is roughly equivalent to a.fetch_add(12, std::memory_order_seq_cst)
.
As for your comment:
A regular int
has atomic loads and stores. Whats the point of wrapping it with atomic<>
?
Your statement is only true for architectures that provide such guarantee of atomicity for stores and/or loads. There are architectures that do not do this. Also, it is usually required that operations must be performed on word-/dword-aligned address to be atomic std::atomic<>
is something that is guaranteed to be atomic on every platform, without additional requirements. Moreover, it allows you to write code like this:
void* sharedData = nullptr;
std::atomic<int> ready_flag = 0;
// Thread 1
void produce()
{
sharedData = generateData();
ready_flag.store(1, std::memory_order_release);
}
// Thread 2
void consume()
{
while (ready_flag.load(std::memory_order_acquire) == 0)
{
std::this_thread::yield();
}
assert(sharedData != nullptr); // will never trigger
processData(sharedData);
}
Note that assertion condition will always be true (and thus, will never trigger), so you can always be sure that data is ready after while
loop exits. That is because:
store()
to the flag is performed after sharedData
is set (we assume that generateData()
always returns something useful, in particular, never returns NULL
) and uses std::memory_order_release
order:
memory_order_release
A store operation with this memory order performs the release
operation: no reads or writes in the current thread can be reordered
after this store. All writes in the current thread are visible in
other threads that acquire the same atomic variable
sharedData
is used after while
loop exits, and thus after load()
from flag will return a non-zero value. load()
uses std::memory_order_acquire
order:
std::memory_order_acquire
A load operation with this memory order performs the acquire operation
on the affected memory location: no reads or writes in the current
thread can be reordered before this load. All writes in other threads
that release the same atomic variable are visible in the current
thread.
This gives you precise control over the synchronization and allows you to explicitly specify how your code may/may not/will/will not behave. This would not be possible if only guarantee was the atomicity itself. Especially when it comes to very interesting sync models like the release-consume ordering.
How to do this using jQuery - document.getElementById("selectlist").value
"Equivalent" is the word here
While...
$('#selectlist').val();
...is equivalent to...
document.getElementById("selectlist").value
...it's worth noting that...
$('#selectlist')
...although 'equivalent' is not the same as...
document.getElementById("selectlist")
...as the former returns a jQuery object, not a DOM object.
To get the DOM object(s) from the jQuery one, use the following:
$('#selectlist').get(); //get all DOM objects in the jQuery collection
$('#selectlist').get(0); //get the DOM object in the jQuery collection at index 0
$('#selectlist')[0]; //get the DOM objects in the jQuery collection at index 0
What is the lifetime of a static variable in a C++ function?
Motti is right about the order, but there are some other things to consider:
Compilers typically use a hidden flag variable to indicate if the local statics have already been initialized, and this flag is checked on every entry to the function. Obviously this is a small performance hit, but what's more of a concern is that this flag is not guaranteed to be thread-safe.
If you have a local static as above, and foo
is called from multiple threads, you may have race conditions causing plonk
to be initialized incorrectly or even multiple times. Also, in this case plonk
may get destructed by a different thread than the one which constructed it.
Despite what the standard says, I'd be very wary of the actual order of local static destruction, because it's possible that you may unwittingly rely on a static being still valid after it's been destructed, and this is really difficult to track down.
<Django object > is not JSON serializable
simplejson
and json
don't work with django objects well.
Django's built-in serializers can only serialize querysets filled with django objects:
data = serializers.serialize('json', self.get_queryset())
return HttpResponse(data, content_type="application/json")
In your case, self.get_queryset()
contains a mix of django objects and dicts inside.
One option is to get rid of model instances in the self.get_queryset()
and replace them with dicts using model_to_dict
:
from django.forms.models import model_to_dict
data = self.get_queryset()
for item in data:
item['product'] = model_to_dict(item['product'])
return HttpResponse(json.simplejson.dumps(data), mimetype="application/json")
Hope that helps.
IIS7 Cache-Control
That's not true Jeff.
You simply have to select a folder within your IIS 7 Manager UI (e.g. Images or event the Default Web Application folder) and then click on "HTTP Response Headers". Then you have to click on "Set Common Header.." in the right pane and select the "Expire Web content". There you can easily configure a max-age of 24 hours by choosing "After:", entering "24" in the Textbox and choose "Hours" in the combobox.
Your first paragraph regarding the web.config entry is right. I'd add the cacheControlCustom-attribute to set the cache control header to "public" or whatever is needed in that case.
You can, of course, achieve the same by providing web.config entries (or files) as needed.
Edit: removed a confusing sentence :)
Changing text color onclick
<p id="text" onclick="func()">
Click on text to change
</p>
<script>
function func()
{
document.getElementById("text").style.color="red";
document.getElementById("text").style.font="calibri";
}
</script>
Why does instanceof return false for some literals?
Or you can just make your own function like so:
function isInstanceOf(obj, clazz){
return (obj instanceof eval("("+clazz+")")) || (typeof obj == clazz.toLowerCase());
};
usage:
isInstanceOf('','String');
isInstanceOf(new String(), 'String');
These should both return true.
How to center form in bootstrap 3
There is a simple way of doing this in Bootstrap. Whenever I need to make a div
center in a page, I divide all columns by 3 (total Bootstrap columns = 12, divided by 3 >>> 12/3 = 4). Dividing by four gives me three columns. Then I put my div
in middle column. And all this math is performed by this way:
<div class="col-md-4 col-md-offset-4">my div here</div>
col-md-4
makes one column of 4 Bootstrap columns. Let's say it's the main column. col-md-offset-4
adds one column (of width of 4 Bootstrap column) to both sides of the main column.
How do you overcome the HTML form nesting limitation?
I know this is an old question, but HTML5 offers a couple new options.
The first is to separate the form from the toolbar in the markup, add another form for the delete action, and associate the buttons in the toolbar with their respective forms using the form
attribute.
<form id="saveForm" action="/post/dispatch/save" method="post">
<input type="text" name="foo" /> <!-- several of those here -->
</form>
<form id="deleteForm" action="/post/dispatch/delete" method="post">
<input type="hidden" value="some_id" />
</form>
<div id="toolbar">
<input type="submit" name="save" value="Save" form="saveForm" />
<input type="submit" name="delete" value="Delete" form="deleteForm" />
<a href="/home/index">Cancel</a>
</div>
This option is quite flexible, but the original post also mentioned that it may be necessary to perform different actions with a single form. HTML5 comes to the rescue, again. You can use the formaction
attribute on submit buttons, so different buttons in the same form can submit to different URLs. This example just adds a clone method to the toolbar outside the form, but it would work the same nested in the form.
<div id="toolbar">
<input type="submit" name="clone" value="Clone" form="saveForm"
formaction="/post/dispatch/clone" />
</div>
http://www.whatwg.org/specs/web-apps/current-work/#attributes-for-form-submission
The advantage of these new features is that they do all this declaratively without JavaScript. The disadvantage is that they are not supported on older browsers, so you'd have to do some polyfilling for older browsers.
How to fix the "508 Resource Limit is reached" error in WordPress?
I faced to this problem a lot when developing my company's website using WordPress. Finally I found that it happened because me and my colleague update the website at the same time as well as we installed and activated many plugins that we did not use them. The solution for me was we update the website in different time and deactivated and uninstalled those plugins.
How can I write data in YAML format in a file?
import yaml
data = dict(
A = 'a',
B = dict(
C = 'c',
D = 'd',
E = 'e',
)
)
with open('data.yml', 'w') as outfile:
yaml.dump(data, outfile, default_flow_style=False)
The default_flow_style=False
parameter is necessary to produce the format you want (flow style), otherwise for nested collections it produces block style:
A: a
B: {C: c, D: d, E: e}
How do I center a window onscreen in C#?
Might not be completely relevant to the question. But maybe can help someone.
Center Screen non of the above work for me. Reason was I was adding controls dynamically to the form. Technically when it centered it was correct , based on the form before adding the controls.
So here was my solution. ( Should work with both scenarios )
int x = Screen.PrimaryScreen.Bounds.Width - this.PreferredSize.Width;
int y = Screen.PrimaryScreen.Bounds.Height - this.PreferredSize.Height;
this.Location = new Point(x / 2, y / 2);
So you will notice that I am using "PreferredSize" instead of just using Height / Width.
The preferred size will hold the value of the form after adding the controls. Where Height / Width won't.
Hope this helps someone .
Cheers
function is not defined error in Python
Yes, but in what file is pyth_test
's definition declared in? Is it also located before it's called?
Edit:
To put it into perspective, create a file called test.py
with the following contents:
def pyth_test (x1, x2):
print x1 + x2
pyth_test(1,2)
Now run the following command:
python test.py
You should see the output you desire. Now if you are in an interactive session, it should go like this:
>>> def pyth_test (x1, x2):
... print x1 + x2
...
>>> pyth_test(1,2)
3
>>>
I hope this explains how the declaration works.
To give you an idea of how the layout works, we'll create a few files. Create a new empty folder to keep things clean with the following:
myfunction.py
def pyth_test (x1, x2):
print x1 + x2
program.py
#!/usr/bin/python
# Our function is pulled in here
from myfunction import pyth_test
pyth_test(1,2)
Now if you run:
python program.py
It will print out 3. Now to explain what went wrong, let's modify our program this way:
# Python: Huh? where's pyth_test?
# You say it's down there, but I haven't gotten there yet!
pyth_test(1,2)
# Our function is pulled in here
from myfunction import pyth_test
Now let's see what happens:
$ python program.py
Traceback (most recent call last):
File "program.py", line 3, in <module>
pyth_test(1,2)
NameError: name 'pyth_test' is not defined
As noted, python cannot find the module for the reasons outlined above. For that reason, you should keep your declarations at top.
Now then, if we run the interactive python session:
>>> from myfunction import pyth_test
>>> pyth_test(1,2)
3
The same process applies. Now, package importing isn't all that simple, so I recommend you look into how modules work with Python. I hope this helps and good luck with your learnings!
How do I clear my Jenkins/Hudson build history?
If you want to clear the build history of MultiBranchProject (e.g. pipeline),
go to your Jenkins home page ? Manage Jenkins ? Script Console and run the following script:
def projectName = "ProjectName"
def project = Jenkins.instance.getItem(projectName)
def jobs = project.getItems().each {
def job = it
job.getBuilds().each { it.delete() }
job.nextBuildNumber = 1
job.save()
}
c# regex matches example
public void match2()
{
string input = "%download%#893434";
Regex word = new Regex(@"\d+");
Match m = word.Match(input);
Console.WriteLine(m.Value);
}
Adding header to all request with Retrofit 2
Try this type header for Retrofit 1.9 and 2.0. For Json Content Type.
@Headers({"Accept: application/json"})
@POST("user/classes")
Call<playlist> addToPlaylist(@Body PlaylistParm parm);
You can add many more headers i.e
@Headers({
"Accept: application/json",
"User-Agent: Your-App-Name",
"Cache-Control: max-age=640000"
})
Dynamically Add to headers:
@POST("user/classes")
Call<ResponseModel> addToPlaylist(@Header("Content-Type") String content_type, @Body RequestModel req);
Call you method i.e
mAPI.addToPlayList("application/json", playListParam);
Or
Want to pass everytime then Create HttpClient object with http Interceptor:
OkHttpClient httpClient = new OkHttpClient();
httpClient.networkInterceptors().add(new Interceptor() {
@Override
public com.squareup.okhttp.Response intercept(Chain chain) throws IOException {
Request.Builder requestBuilder = chain.request().newBuilder();
requestBuilder.header("Content-Type", "application/json");
return chain.proceed(requestBuilder.build());
}
});
Then add to retrofit object
Retrofit retrofit = new Retrofit.Builder().baseUrl(BASE_URL).client(httpClient).build();
UPDATE if you are using Kotlin remove the { }
else it will not work
Javascript Date - set just the date, ignoring time?
_x000D_
_x000D_
var today = new Date();
var year = today.getFullYear();
var mes = today.getMonth()+1;
var dia = today.getDate();
var fecha =dia+"-"+mes+"-"+year;
console.log(fecha);
_x000D_
_x000D_
_x000D_
C++ Object Instantiation
The only reason I'd worry about is that Dog is now allocated on the stack, rather than the heap. So if Dog is megabytes in size, you may have a problem,
If you do need to go the new/delete route, be wary of exceptions. And because of this you should use auto_ptr or one of the boost smart pointer types to manage the object lifetime.
SQL WHERE ID IN (id1, id2, ..., idn)
An alternative approach might be to use another table to contain id values. This other table can then be inner joined on your TABLE to constrain returned rows. This will have the major advantage that you won't need dynamic SQL (problematic at the best of times), and you won't have an infinitely long IN clause.
You would truncate this other table, insert your large number of rows, then perhaps create an index to aid the join performance. It would also let you detach the accumulation of these rows from the retrieval of data, perhaps giving you more options to tune performance.
Update: Although you could use a temporary table, I did not mean to imply that you must or even should. A permanent table used for temporary data is a common solution with merits beyond that described here.
SQL LIKE condition to check for integer?
Assuming that you're looking for "numbers that start with 7" rather than "strings that start with 7," maybe something like
select * from books where convert(char(32), book_id) like '7%'
Or whatever the Postgres equivalent of convert is.
How to enable assembly bind failure logging (Fusion) in .NET
You can run this Powershell script as administrator to enable FL:
Set-ItemProperty -Path HKLM:\Software\Microsoft\Fusion -Name ForceLog -Value 1 -Type DWord
Set-ItemProperty -Path HKLM:\Software\Microsoft\Fusion -Name LogFailures -Value 1 -Type DWord
Set-ItemProperty -Path HKLM:\Software\Microsoft\Fusion -Name LogResourceBinds -Value 1 -Type DWord
Set-ItemProperty -Path HKLM:\Software\Microsoft\Fusion -Name LogPath -Value 'C:\FusionLog\' -Type String
mkdir C:\FusionLog -Force
and this one to disable:
Remove-ItemProperty -Path HKLM:\Software\Microsoft\Fusion -Name ForceLog
Remove-ItemProperty -Path HKLM:\Software\Microsoft\Fusion -Name LogFailures
Remove-ItemProperty -Path HKLM:\Software\Microsoft\Fusion -Name LogResourceBinds
Remove-ItemProperty -Path HKLM:\Software\Microsoft\Fusion -Name LogPath