How do you recursively unzip archives in a directory and its subdirectories from the Unix command-line?
I realise this is very old, but it was among the first hits on Google when I was looking for a solution to something similar, so I'll post what I did here. My scenario is slightly different as I basically just wanted to fully explode a jar, along with all jars contained within it, so I wrote the following bash functions:
function explode {
local target="$1"
echo "Exploding $target."
if [ -f "$target" ] ; then
explodeFile "$target"
elif [ -d "$target" ] ; then
while [ "$(find "$target" -type f -regextype posix-egrep -iregex ".*\.(zip|jar|ear|war|sar)")" != "" ] ; do
find "$target" -type f -regextype posix-egrep -iregex ".*\.(zip|jar|ear|war|sar)" -exec bash -c 'source "<file-where-this-function-is-stored>" ; explode "{}"' \;
done
else
echo "Could not find $target."
fi
}
function explodeFile {
local target="$1"
echo "Exploding file $target."
mv "$target" "$target.tmp"
unzip -q "$target.tmp" -d "$target"
rm "$target.tmp"
}
Note the <file-where-this-function-is-stored>
which is needed if you're storing this in a file that is not read for a non-interactive shell as I happened to be. If you're storing the functions in a file loaded on non-interactive shells (e.g., .bashrc
I believe) you can drop the whole source
statement. Hopefully this will help someone.
A little warning - explodeFile
also deletes the ziped file, you can of course change that by commenting out the last line.
Android WebView Cookie Problem
I magically solved all my cookie problems with this one line in onCreate:
CookieHandler.setDefault(new CookieManager());
edit: it stopped working today. :( what the crap, android.
Change user-agent for Selenium web-driver
To build on Louis's helpful answer...
Setting the User Agent in PhantomJS
from selenium import webdriver
from selenium.webdriver.common.desired_capabilities import DesiredCapabilities
...
caps = DesiredCapabilities.PHANTOMJS
caps["phantomjs.page.settings.userAgent"] = "whatever you want"
driver = webdriver.PhantomJS(desired_capabilities=caps)
The only minor issue is that, unlike for Firefox and Chrome, this does not return your custom setting:
driver.execute_script("return navigator.userAgent")
So, if anyone figures out how to do that in PhantomJS, please edit my answer or add a comment below! Cheers.
How to undo a successful "git cherry-pick"?
One command and does not use the destructive git reset
command:
GIT_SEQUENCE_EDITOR="sed -i 's/pick/d/'" git rebase -i HEAD~ --autostash
It simply drops the commit, putting you back exactly in the state before the cherry-pick even if you had local changes.
Change the Blank Cells to "NA"
My function takes into account factor, character vector and potential attributes, if you use haven or foreign package to read external files. Also it allows matching different self-defined na.strings. To transform all columns, simply use lappy: df[] = lapply(df, blank2na, na.strings=c('','NA','na','N/A','n/a','NaN','nan'))
See more the comments:
#' Replaces blank-ish elements of a factor or character vector to NA
#' @description Replaces blank-ish elements of a factor or character vector to NA
#' @param x a vector of factor or character or any type
#' @param na.strings case sensitive strings that will be coverted to NA. The function will do a trimws(x,'both') before conversion. If NULL, do only trimws, no conversion to NA.
#' @return Returns a vector trimws (always for factor, character) and NA converted (if matching na.strings). Attributes will also be kept ('label','labels', 'value.labels').
#' @seealso \code{\link{ez.nan2na}}
#' @export
blank2na = function(x,na.strings=c('','.','NA','na','N/A','n/a','NaN','nan')) {
if (is.factor(x)) {
lab = attr(x, 'label', exact = T)
labs1 <- attr(x, 'labels', exact = T)
labs2 <- attr(x, 'value.labels', exact = T)
# trimws will convert factor to character
x = trimws(x,'both')
if (! is.null(lab)) lab = trimws(lab,'both')
if (! is.null(labs1)) labs1 = trimws(labs1,'both')
if (! is.null(labs2)) labs2 = trimws(labs2,'both')
if (!is.null(na.strings)) {
# convert to NA
x[x %in% na.strings] = NA
# also remember to remove na.strings from value labels
labs1 = labs1[! labs1 %in% na.strings]
labs2 = labs2[! labs2 %in% na.strings]
}
# the levels will be reset here
x = factor(x)
if (! is.null(lab)) attr(x, 'label') <- lab
if (! is.null(labs1)) attr(x, 'labels') <- labs1
if (! is.null(labs2)) attr(x, 'value.labels') <- labs2
} else if (is.character(x)) {
lab = attr(x, 'label', exact = T)
labs1 <- attr(x, 'labels', exact = T)
labs2 <- attr(x, 'value.labels', exact = T)
# trimws will convert factor to character
x = trimws(x,'both')
if (! is.null(lab)) lab = trimws(lab,'both')
if (! is.null(labs1)) labs1 = trimws(labs1,'both')
if (! is.null(labs2)) labs2 = trimws(labs2,'both')
if (!is.null(na.strings)) {
# convert to NA
x[x %in% na.strings] = NA
# also remember to remove na.strings from value labels
labs1 = labs1[! labs1 %in% na.strings]
labs2 = labs2[! labs2 %in% na.strings]
}
if (! is.null(lab)) attr(x, 'label') <- lab
if (! is.null(labs1)) attr(x, 'labels') <- labs1
if (! is.null(labs2)) attr(x, 'value.labels') <- labs2
} else {
x = x
}
return(x)
}
how to make UITextView height dynamic according to text length?
1 Add an observer to the content length of textfield
yourTextView.addObserver(self, forKeyPath: "contentSize", options: (NSKeyValueObservingOptions.new), context: nil);
2 Implement observer
override func observeValue(forKeyPath keyPath: String?, of object: Any?, change: [NSKeyValueChangeKey : Any]?, context: UnsafeMutableRawPointer?) {
let tv = object as! UITextView;
var topCorrect = (tv.bounds.size.height - tv.contentSize.height * tv.zoomScale)/2.0;
topCorrect = ( topCorrect < 0.0 ? 0.0 : topCorrect );
tv.contentOffset.x = 0;
tv.contentOffset.y = -topCorrect;
self.yourTextView.contentSize.height = tv.contentSize.height;
UIView.animate(withDuration: 0.2, animations: {
self.view.layoutIfNeeded();
});
}
Generate JSON string from NSDictionary in iOS
public func jsonPrint(_ o: NSObject, spacing: String = "", after: String = "", before: String = "") {
let newSpacing = spacing + " "
if o.isArray() {
print(before + "[")
if let a = o as? Array<NSObject> {
for object in a {
jsonPrint(object, spacing: newSpacing, after: object == a.last! ? "" : ",", before: newSpacing)
}
}
print(spacing + "]" + after)
} else {
if o.isDictionary() {
print(before + "{")
if let a = o as? Dictionary<NSObject, NSObject> {
for (key, val) in a {
jsonPrint(val, spacing: newSpacing, after: ",", before: newSpacing + key.description + " = ")
}
}
print(spacing + "}" + after)
} else {
print(before + o.description + after)
}
}
}
This one is pretty close to original Objective-C print style
Display Image On Text Link Hover CSS Only
It is not possible to do this with just CSS alone, you will need to use Javascript.
<img src="default_image.jpg" id="image" width="100" height="100" alt="" />
<a href="page.html" onmouseover="document.images['image'].src='mouseover.jpg';" onmouseout="document.images['image'].src='default_image.jpg';"/>Text</a>
How to change the value of attribute in appSettings section with Web.config transformation
Replacing all AppSettings
This is the overkill case where you just want to replace an entire section of the web.config. In this case I will replace all AppSettings in the web.config will new settings in web.release.config. This is my baseline web.config appSettings:
<appSettings>
<add key="KeyA" value="ValA"/>
<add key="KeyB" value="ValB"/>
</appSettings>
Now in my web.release.config file, I am going to create a appSettings section except I will include the attribute xdt:Transform=”Replace” since I want to just replace the entire element. I did not have to use xdt:Locator because there is nothing to locate – I just want to wipe the slate clean and replace everything.
<appSettings xdt:Transform="Replace">
<add key="ProdKeyA" value="ProdValA"/>
<add key="ProdKeyB" value="ProdValB"/>
<add key="ProdKeyC" value="ProdValC"/>
</appSettings>
Note that in the web.release.config file my appSettings section has three keys instead of two, and the keys aren’t even the same. Now let’s look at the generated web.config file what happens when we publish:
<appSettings>
<add key="ProdKeyA" value="ProdValA"/>
<add key="ProdKeyB" value="ProdValB"/>
<add key="ProdKeyC" value="ProdValC"/>
</appSettings>
Just as we expected – the web.config appSettings were completely replaced by the values in web.release config. That was easy!
Find a value in an array of objects in Javascript
Either use a simple for
-loop:
var result = null;
for (var i = 0; i < array.length; i++) {
if (array[i].name === "string 1") {
result = array[i];
break;
}
}
Or if you can, that is, if your browser supports it, use Array.filter
, which is much more terse:
var result = array.filter(function (obj) {
return obj.name === "string 1";
})[0];
JavaScript - get the first day of the week from current date
CMS's answer is correct but assumes that Monday is the first day of the week.
Chandler Zwolle's answer is correct but fiddles with the Date prototype.
Other answers that play with hour/minutes/seconds/milliseconds are wrong.
The function below is correct and takes a date as first parameter and the desired first day of the week as second parameter (0 for Sunday, 1 for Monday, etc.). Note: the hour, minutes and seconds are set to 0 to have the beginning of the day.
_x000D_
_x000D_
function firstDayOfWeek(dateObject, firstDayOfWeekIndex) {_x000D_
_x000D_
const dayOfWeek = dateObject.getDay(),_x000D_
firstDayOfWeek = new Date(dateObject),_x000D_
diff = dayOfWeek >= firstDayOfWeekIndex ?_x000D_
dayOfWeek - firstDayOfWeekIndex :_x000D_
6 - dayOfWeek_x000D_
_x000D_
firstDayOfWeek.setDate(dateObject.getDate() - diff)_x000D_
firstDayOfWeek.setHours(0,0,0,0)_x000D_
_x000D_
return firstDayOfWeek_x000D_
}_x000D_
_x000D_
// August 18th was a Saturday_x000D_
let lastMonday = firstDayOfWeek(new Date('August 18, 2018 03:24:00'), 1)_x000D_
_x000D_
// outputs something like "Mon Aug 13 2018 00:00:00 GMT+0200"_x000D_
// (may vary according to your time zone)_x000D_
document.write(lastMonday)
_x000D_
_x000D_
_x000D_
HTML img tag: title attribute vs. alt attribute?
ALT Attribute
The alt
attribute is defined in a set of tags (namely, img
, area
and optionally for input
and applet
) to allow you to provide a text equivalent for the object.
A text equivalent brings the following benefits to your web site and its visitors in the following common situations:
- nowadays, Web browsers are available in a very wide variety of platforms with very different capacities; some cannot display images at all or only a restricted set of type of images; some can be configured to not load images. If your code has the alt attribute set in its images, most of these browsers will display the description you gave instead of the images
- some of your visitors cannot see images, be they blind, color-blind, low-sighted; the alt attribute is of great help for those people that can rely on it to have a good idea of what's on your page
- search engine bots belong to the two above categories: if you want your website to be indexed as well as it deserves, use the alt attribute to make sure that they won't miss important sections of your pages.
Title Attribute
The objective of this technique is to provide context sensitive help for users as they enter data in forms by providing the help information in a title
attribute. The help may include format information or examples of input.
Example 1: A pulldown menu that limits the scope of a search
A search form uses a pulldown menu to limit the scope of the search. The pulldown menu is immediately adjacent to the text field used to enter the search term. The relationship between the search field and the pulldown menu is clear to users who can see the visual design, which does not have room for a visible label. The title
attribute is used to identify the select
menu. The title
attribute can be spoken by screen readers or displayed as a tool tip for people using screen magnifiers.
<label for="searchTerm">Search for:</label>
<input id="searchTerm" type="text" size="30" value="" name="searchTerm">
<select title="Search in" id="scope">
...
</select>
Example 2: Input fields for a phone number
A Web page contains controls for entering a phone number in the United States, with three fields for area code, exchange, and last four digits.
<fieldset>
<legend>Phone number</legend>
<input id="areaCode" name="areaCode" title="Area Code" type="text" size="3" value="" >
<input id="exchange" name="exchange" title="First three digits of phone number" type="text" size="3" value="" >
<input id="lastDigits" name="lastDigits" title="Last four digits of phone number" type="text" size="4" value="" >
</fieldset>
Example 3: A Search Function
A Web page contains a text field where the user can enter search terms and a button labeled "Search" for performing the search. The title
attribute is used to identify the form control and the button is positioned right after the text field so that it is clear to the user that the text field is where the search term should be entered.
<input type="text" title="Type search term here"/> <input type="submit" value="Search"/>
Example 4: A data table of form controls
A data table of form controls needs to associate each control with the column and row headers for that cell. Without a title (or off-screen LABEL) it is difficult for non-visual users to pause and interrogate for corresponding row/column header values using their assistive technology while tabbing through the form.
For example, a survey form has four column headers in first row: Question, Agree, Undecided, Disagree. Each following row contains a question and a radio button in each cell corresponding to answer choice in the three columns. The title attribute for every radio button is a concatenation of the answer choice (column header) and the text of the question (row header) with a hyphen or colon as a separator.
Img Element
Allowed attributes mentioned at MDN.
alt
crossorigin
decoding
height
importance
(experimental api)
intrinsicsize
(experimental api)
ismap
referrerpolicy
(experimental api)
src
srcset
width
usemap
As you can see title
attribute is not allowed inside img
element. I would use alt
attribute and if requires I would use CSS (Example: pseudo class :hover
) instead of title
attribute.
Get current AUTO_INCREMENT value for any table
mysqli executable sample code:
<?php
$db = new mysqli("localhost", "user", "password", "YourDatabaseName");
if ($db->connect_errno) die ($db->connect_error);
$table=$db->prepare("SHOW TABLE STATUS FROM YourDatabaseName");
$table->execute();
$sonuc = $table->get_result();
while ($satir=$sonuc->fetch_assoc()){
if ($satir["Name"]== "YourTableName"){
$ai[$satir["Name"]]=$satir["Auto_increment"];
}
}
$LastAutoIncrement=$ai["YourTableName"];
echo $LastAutoIncrement;
?>
nginx - client_max_body_size has no effect
Assuming you have already set the client_max_body_size and various PHP settings (upload_max_filesize / post_max_size , etc) in the other answers, then restarted or reloaded NGINX and PHP without any result, run this...
nginx -T
This will give you any unresolved errors in your NGINX configs. In my case, I struggled with the 413 error for a whole day before I realized there were some other unresolved SSL errors in the NGINX config (wrong pathing for certs) that needed to be corrected. Once I fixed the unresolved issues I got from 'nginx -T', reloaded NGINX, and EUREKA!! That fixed it.
ASP.NET Bundles how to disable minification
You can turn off minification in your bundles simply by Clearing your transforms.
var scriptBundle = new ScriptBundle("~/bundles/scriptBundle");
...
scriptBundle.Transforms.Clear();
I personally found this useful when wanting to bundle all my scripts in a single file but needed readability during debugging phases.
Memory errors and list limits?
The MemoryError
exception that you are seeing is the direct result of running out of available RAM. This could be caused by either the 2GB per program limit imposed by Windows (32bit programs), or lack of available RAM on your computer. (This link is to a previous question).
You should be able to extend the 2GB by using 64bit copy of Python, provided you are using a 64bit copy of windows.
The IndexError
would be caused because Python hit the MemoryError
exception before calculating the entire array. Again this is a memory issue.
To get around this problem you could try to use a 64bit copy of Python or better still find a way to write you results to file. To this end look at numpy's memory mapped arrays.
You should be able to run you entire set of calculation into one of these arrays as the actual data will be written disk, and only a small portion of it held in memory.
Cannot set property 'display' of undefined
I've found this answer in the site https://plainjs.com/javascript/styles/set-and-get-css-styles-of-elements-53/.
In this code we add multiple styles in an element:
_x000D_
_x000D_
let_x000D_
element = document.querySelector('span')_x000D_
, cssStyle = (el, styles) => {_x000D_
for (var property in styles) {_x000D_
el.style[property] = styles[property];_x000D_
}_x000D_
}_x000D_
;_x000D_
_x000D_
cssStyle(element, { background:'tomato', color: 'white', padding: '0.5rem 1rem'});
_x000D_
span{_x000D_
font-family: sans-serif;_x000D_
color: #323232;_x000D_
background: #fff;_x000D_
}
_x000D_
<span>_x000D_
lorem ipsum_x000D_
</span>
_x000D_
_x000D_
_x000D_
How to save username and password in Git?
None of the answers above worked for me. I kept getting the following every time I wanted to fetch
or pull
:
Enter passphrase for key '/Users/myusername/.ssh/id_rsa':
For Macs
I was able to stop it from asking my passphrase by:
- Open config by running:
vi ~/.ssh/config
- Added the following:
UseKeychain yes
- Saved and quit: Press Esc, then enter
:wq!
For Windows
I was able to get it to work using the info in this stackexchange:
https://unix.stackexchange.com/a/12201/348665
Retrieving Property name from lambda expression
I created an extension method on ObjectStateEntry to be able to flag properties (of Entity Framework POCO classes) as modified in a type safe manner, since the default method only accepts a string. Here's my way of getting the name from the property:
public static void SetModifiedProperty<T>(this System.Data.Objects.ObjectStateEntry state, Expression<Func<T>> action)
{
var body = (MemberExpression)action.Body;
string propertyName = body.Member.Name;
state.SetModifiedProperty(propertyName);
}
converting CSV/XLS to JSON?
See if this helps: Back to CSV - Convert CSV text to Objects; via JSON
This is a blog post published in November 2008 that includes C# code to provide a solution.
From the intro on the blog post:
As Json is easier to read and write then Xml. It follows that CSV (comma seperated values) is easier to read and write then Json. CSV also has tools such as Excel and others that make it easy to work with and create. So if you ever want to create a config or data file for your next app, here is some code to convert CSV to JSON to POCO objects
Javascript equivalent of php's strtotime()?
_x000D_
_x000D_
var strdate = new Date('Tue Feb 07 2017 12:51:48 GMT+0200 (Türkiye Standart Saati)');_x000D_
var date = moment(strdate).format('DD.MM.YYYY');_x000D_
$("#result").text(date); //07.02.2017
_x000D_
<script src="https://code.jquery.com/jquery-1.9.1.min.js"></script>_x000D_
<script src="https://cdnjs.cloudflare.com/ajax/libs/moment.js/2.17.1/moment.js"></script>_x000D_
_x000D_
<div id="result"></div>
_x000D_
_x000D_
_x000D_
Create tap-able "links" in the NSAttributedString of a UILabel?
This generic method works too !
func didTapAttributedTextInLabel(gesture: UITapGestureRecognizer, inRange targetRange: NSRange) -> Bool {
let layoutManager = NSLayoutManager()
let textContainer = NSTextContainer(size: CGSize.zero)
guard let strAttributedText = self.attributedText else {
return false
}
let textStorage = NSTextStorage(attributedString: strAttributedText)
// Configure layoutManager and textStorage
layoutManager.addTextContainer(textContainer)
textStorage.addLayoutManager(layoutManager)
// Configure textContainer
textContainer.lineFragmentPadding = Constants.lineFragmentPadding
textContainer.lineBreakMode = self.lineBreakMode
textContainer.maximumNumberOfLines = self.numberOfLines
let labelSize = self.bounds.size
textContainer.size = CGSize(width: labelSize.width, height: CGFloat.greatestFiniteMagnitude)
// Find the tapped character location and compare it to the specified range
let locationOfTouchInLabel = gesture.location(in: self)
let xCordLocationOfTouchInTextContainer = locationOfTouchInLabel.x
let yCordLocationOfTouchInTextContainer = locationOfTouchInLabel.y
let locOfTouch = CGPoint(x: xCordLocationOfTouchInTextContainer ,
y: yCordLocationOfTouchInTextContainer)
let indexOfCharacter = layoutManager.characterIndex(for: locOfTouch, in: textContainer, fractionOfDistanceBetweenInsertionPoints: nil)
guard let strLabel = text else {
return false
}
let charCountOfLabel = strLabel.count
if indexOfCharacter < (charCountOfLabel - 1) {
return NSLocationInRange(indexOfCharacter, targetRange)
} else {
return false
}
}
And you can call the method with
let text = yourLabel.text
let termsRange = (text as NSString).range(of: fullString)
if yourLabel.didTapAttributedTextInLabel(gesture: UITapGestureRecognizer, inRange: termsRange) {
showCorrespondingViewController()
}
android listview item height
I did something like that :
@Override
public View getView(int position, View convertView, ViewGroup parent) {
View view = super.getView(position, convertView, parent);
TextView textView = (TextView) view.findViewById(android.R.id.text1);
textView.setHeight(30);
textView.setMinimumHeight(30);
/*YOUR CHOICE OF COLOR*/
textView.setTextColor(Color.BLACK);
return view;
}
You must put the both fields textView.setHeight(30);
textView.setMinimumHeight(30); or it won't change anything. For me it worked & i had the same problem.
How to make Visual Studio copy a DLL file to the output directory?
$(OutDir) turned out to be a relative path in VS2013, so I had to combine it with $(ProjectDir) to achieve the desired effect:
xcopy /y /d "$(ProjectDir)External\*.dll" "$(ProjectDir)$(OutDir)"
BTW, you can easily debug the scripts by adding 'echo ' at the beginning and observe the expanded text in the build output window.
How to copy a file from remote server to local machine?
The scp operation is separate from your ssh login. You will need to issue an ssh command similar to the following one assuming jdoe is account with which you log into the remote system and that the remote system is example.com:
scp [email protected]:/somedir/table /home/me/Desktop/.
The scp command issued from the system where /home/me/Desktop resides is followed by the userid for the account on the remote server. You then add a ":" followed by the directory path and file name on the remote server, e.g., /somedir/table. Then add a space and the location to which you want to copy the file. If you want the file to have the same name on the client system, you can indicate that with a period, i.e. "." at the end of the directory path; if you want a different name you could use /home/me/Desktop/newname, instead. If you were using a nonstandard port for SSH connections, you would need to specify that port with a "-P n" (capital P), where "n" is the port number. The standard port is 22 and if you aren't specifying it for the SSH connection then you won't need that.
Checking to see if a DateTime variable has had a value assigned
I generally prefer, where possible, to use the default value of value types to determine whether they've been set. This obviously isn't possible all the time, especially with ints - but for DateTimes, I think reserving the MinValue to signify that it hasn't been changed is fair enough. The benefit of this over nullables is that there's one less place where you'll get a null reference exception (and probably lots of places where you don't have to check for null before accessing it!)
How to compare dates in datetime fields in Postgresql?
@Nicolai is correct about casting and why the condition is false for any data. i guess you prefer the first form because you want to avoid date manipulation on the input string, correct? you don't need to be afraid:
SELECT *
FROM table
WHERE update_date >= '2013-05-03'::date
AND update_date < ('2013-05-03'::date + '1 day'::interval);
Short description of the scoping rules?
There was no thorough answer concerning Python3 time, so I made an answer here. Most of what is described here is detailed in the 4.2.2 Resolution of names of the Python 3 documentation.
As provided in other answers, there are 4 basic scopes, the LEGB, for Local, Enclosing, Global and Builtin. In addition to those, there is a special scope, the class body, which does not comprise an enclosing scope for methods defined within the class; any assignments within the class body make the variable from there on be bound in the class body.
Especially, no block statement, besides def
and class
, create a variable scope. In Python 2 a list comprehension does not create a variable scope, however in Python 3 the loop variable within list comprehensions is created in a new scope.
To demonstrate the peculiarities of the class body
x = 0
class X(object):
y = x
x = x + 1 # x is now a variable
z = x
def method(self):
print(self.x) # -> 1
print(x) # -> 0, the global x
print(y) # -> NameError: global name 'y' is not defined
inst = X()
print(inst.x, inst.y, inst.z, x) # -> (1, 0, 1, 0)
Thus unlike in function body, you can reassign the variable to the same name in class body, to get a class variable with the same name; further lookups on this name resolve
to the class variable instead.
One of the greater surprises to many newcomers to Python is that a for
loop does not create a variable scope. In Python 2 the list comprehensions do not create a scope either (while generators and dict comprehensions do!) Instead they leak the value in the function or the global scope:
>>> [ i for i in range(5) ]
>>> i
4
The comprehensions can be used as a cunning (or awful if you will) way to make modifiable variables within lambda expressions in Python 2 - a lambda expression does create a variable scope, like the def
statement would, but within lambda no statements are allowed. Assignment being a statement in Python means that no variable assignments in lambda are allowed, but a list comprehension is an expression...
This behaviour has been fixed in Python 3 - no comprehension expressions or generators leak variables.
The global really means the module scope; the main python module is the __main__
; all imported modules are accessible through the sys.modules
variable; to get access to __main__
one can use sys.modules['__main__']
, or import __main__
; it is perfectly acceptable to access and assign attributes there; they will show up as variables in the global scope of the main module.
If a name is ever assigned to in the current scope (except in the class scope), it will be considered belonging to that scope, otherwise it will be considered to belonging to any enclosing scope that assigns to the variable (it might not be assigned yet, or not at all), or finally the global scope. If the variable is considered local, but it is not set yet, or has been deleted, reading the variable value will result in UnboundLocalError
, which is a subclass of NameError
.
x = 5
def foobar():
print(x) # causes UnboundLocalError!
x += 1 # because assignment here makes x a local variable within the function
# call the function
foobar()
The scope can declare that it explicitly wants to modify the global (module scope) variable, with the global keyword:
x = 5
def foobar():
global x
print(x)
x += 1
foobar() # -> 5
print(x) # -> 6
This also is possible even if it was shadowed in enclosing scope:
x = 5
y = 13
def make_closure():
x = 42
y = 911
def func():
global x # sees the global value
print(x, y)
x += 1
return func
func = make_closure()
func() # -> 5 911
print(x, y) # -> 6 13
In python 2 there is no easy way to modify the value in the enclosing scope; usually this is simulated by having a mutable value, such as a list with length of 1:
def make_closure():
value = [0]
def get_next_value():
value[0] += 1
return value[0]
return get_next_value
get_next = make_closure()
print(get_next()) # -> 1
print(get_next()) # -> 2
However in python 3, the nonlocal
comes to rescue:
def make_closure():
value = 0
def get_next_value():
nonlocal value
value += 1
return value
return get_next_value
get_next = make_closure() # identical behavior to the previous example.
The nonlocal
documentation says that
Names listed in a nonlocal statement, unlike those listed in a global statement, must refer to pre-existing bindings in an enclosing scope (the scope in which a new binding should be created cannot be determined unambiguously).
i.e. nonlocal
always refers to the innermost outer non-global scope where the name has been bound (i.e. assigned to, including used as the for
target variable, in the with
clause, or as a function parameter).
Any variable that is not deemed to be local to the current scope, or any enclosing scope, is a global variable. A global name is looked up in the module global dictionary; if not found, the global is then looked up from the builtins module; the name of the module was changed from python 2 to python 3; in python 2 it was __builtin__
and in python 3 it is now called builtins
. If you assign to an attribute of builtins module, it will be visible thereafter to any module as a readable global variable, unless that module shadows them with its own global variable with the same name.
Reading the builtin module can also be useful; suppose that you want the python 3 style print function in some parts of file, but other parts of file still use the print
statement. In Python 2.6-2.7 you can get hold of the Python 3 print
function with:
import __builtin__
print3 = __builtin__.__dict__['print']
The from __future__ import print_function
actually does not import the print
function anywhere in Python 2 - instead it just disables the parsing rules for print
statement in the current module, handling print
like any other variable identifier, and thus allowing the print
the function be looked up in the builtins.
WebSockets protocol vs HTTP
For the TL;DR, here are 2 cents and a simpler version for your questions:
WebSockets provides these benefits over HTTP:
- Persistent stateful connection for the duration of the connection
- Low latency: near-real-time communication between server/client due to no overhead of reestablishing connections for each request as HTTP requires.
- Full duplex: both server and client can send/receive simultaneously
WebSocket and HTTP protocol have been designed to solve different problems, I.E. WebSocket was designed to improve bi-directional communication whereas HTTP was designed to be stateless, distributed using a request/response model. Other than sharing the ports for legacy reasons (firewall/proxy penetration), there isn't much common ground to combine them into one protocol.
How to prevent a click on a '#' link from jumping to top of page?
Just use <input type="button" />
instead of <a>
and use CSS to style it to look like a link if you wish.
Buttons are made specifically for clicking, and they don't need any href attributes.
The best way is to use onload action to create the button and append it where you need via javascript, so with javascript disabled, they will not show at all and do not confuse the user.
When you use href="#"
you get tons of different links pointing to the same location, which won't work when the agent does not support JavaScript.
Python memory usage of numpy arrays
The field nbytes will give you the size in bytes of all the elements of the array in a numpy.array
:
size_in_bytes = my_numpy_array.nbytes
Notice that this does not measures "non-element attributes of the array object" so the actual size in bytes can be a few bytes larger than this.
TypeScript error: Type 'void' is not assignable to type 'boolean'
Your code is passing a function as an argument to find
. That function takes an element
argument (of type Conversation
) and returns void
(meaning there is no return value). TypeScript describes this as (element: Conversation) => void'
What TypeScript is saying is that the find
function doesn't expect to receive a function that takes a Conversation and returns void. It expects a function that takes a Conversations
, a number
and a Conversation
array, and that this function should return a boolean
.
So bottom line is that you either need to change your code to pass in the values to find
correctly, or else you need to provide an overload to the definition of find
in your definition file that accepts a Conversation
and returns void
.
Sort a list of Class Instances Python
In addition to the solution you accepted, you could also implement the special __lt__()
("less than") method on the class. The sort()
method (and the sorted()
function) will then be able to compare the objects, and thereby sort them. This works best when you will only ever sort them on this attribute, however.
class Foo(object):
def __init__(self, score):
self.score = score
def __lt__(self, other):
return self.score < other.score
l = [Foo(3), Foo(1), Foo(2)]
l.sort()
MySQL Stored procedure variables from SELECT statements
I am facing a strange behavior.
SELECT INTO and SET Both works for some variables and not for others. Event syntaxes are the same
SET @Invoice_UserId := (SELECT UserId FROM invoice WHERE InvoiceId = @Invoice_Id LIMIT 1); -- Working
SET @myamount := (SELECT amount FROM invoice WHERE InvoiceId = @Invoice_Id LIMIT 1); - Not working
SELECT Amount INTO @myamount FROM invoice WHERE InvoiceId = 29 LIMIT 1; - Not working
If I run these queries directly then works, but not working in stored procedure.
org.hibernate.PersistentObjectException: detached entity passed to persist
This exists in @ManyToOne relation. I solved this issue by just using CascadeType.MERGE instead of CascadeType.PERSIST or CascadeType.ALL. Hope it helps you.
@ManyToOne(cascade = CascadeType.ALL)
@JoinColumn(name="updated_by", referencedColumnName = "id")
private Admin admin;
Solution:
@ManyToOne(cascade = CascadeType.MERGE)
@JoinColumn(name="updated_by", referencedColumnName = "id")
private Admin admin;
How to make exe files from a node.js app?
I'm recommending you BoxedApp for that. It is a commercial product that working very well. It works for any NodeJS app. The end-user will get just one EXE file for your app. No need for installation.
In Electron, for example, the end user needs to install/uncompress your app, and he will see all the source files of your code.
BoxedApp It is packaging all the files and dependencies that your NodeJS app needs.
It supports compressions, and the compiled file works on Windows XP+
When you use it, be sure to add Node.EXE to the compiled app. Choose a node version that supports Windows XP (If you need this)
The program supports command line arguments, So after package, you can do
c:\myApp argument1
And you can get the argument in your node code:
process.argv[1]
Sometimes your app has files dependencies, so in BoxedApp you can add any folder and file as a dependency, for example, you can insert a settings file.
var mySettings=require('fs').readFileSync('./settings.jgon').toString()
More info:
Just a note: usually I'm recommending about open-source/free software, but in this case I didn't found anything that gets the job done.
Placeholder in IE9
Using mordernizr to detect browsers that are not supporting Placeholder, I created this short code to fix them.
//If placeholder is not supported
if (!Modernizr.input.placeholder){
//Loops on inputs and place the placeholder attribute
//in the textbox.
$("input[type=text]").each( function() {
$(this).val($(this).attr('placeholder'));
})
}
What's the difference between xsd:include and xsd:import?
Direct quote from MSDN: <xsd:import> Element, Remarks section
The difference between the include element and the import element is that import element allows references to schema components from schema documents with different target namespaces and the include element adds the schema components from other schema documents that have the same target namespace (or no specified target namespace) to the containing schema. In short, the import element allows you to use schema components from any schema; the include element allows you to add all the components of an included schema to the containing schema.
How do you extract a column from a multi-dimensional array?
let's say we have n X m
matrix(n
rows and m
columns) say 5 rows and 4 columns
matrix = [[1,2,3,4],[5,6,7,8],[9,10,11,12],[13,14,15,16],[17,18,19,20]]
To extract the columns in python, we can use list comprehension like this
[ [row[i] for row in matrix] for in range(4) ]
You can replace 4 by whatever number of columns your matrix has.
The result is
[ [1,5,9,13,17],[2,10,14,18],[3,7,11,15,19],[4,8,12,16,20] ]
Is there a performance difference between CTE , Sub-Query, Temporary Table or Table Variable?
#temp is materalized and CTE is not.
CTE is just syntax so in theory it is just a subquery. It is executed. #temp is materialized. So an expensive CTE in a join that is execute many times may be better in a #temp. On the other side if it is an easy evaluation that is not executed but a few times then not worth the overhead of #temp.
The are some people on SO that don't like table variable but I like them as the are materialized and faster to create than #temp. There are times when the query optimizer does better with a #temp compared to a table variable.
The ability to create a PK on a #temp or table variable gives the query optimizer more information than a CTE (as you cannot declare a PK on a CTE).
Get and Set a Single Cookie with Node.js HTTP Server
First one needs to create cookie (I have wrapped token inside cookie as an example) and then set it in response.To use the cookie in following way install cookieParser
app.use(cookieParser());
The browser will have it saved in its 'Resource' tab and will be used for every request thereafter taking the initial URL as base
var token = student.generateToken('authentication');
res.cookie('token', token, {
expires: new Date(Date.now() + 9999999),
httpOnly: false
}).status(200).send();
To get cookie from a request on the server side is easy too.You have to extract the cookie from request by calling 'cookie' property of the request object.
var token = req.cookies.token; // Retrieving Token stored in cookies
Pass props in Link react-router
Typescript
For approach mentioned like this in many answers,
<Link
to={{
pathname: "/my-path",
myProps: {
hello: "Hello World"
}
}}>
Press Me
</Link>
I was getting error,
Object literal may only specify known properties, and 'myProps' does not exist in type 'LocationDescriptorObject | ((location: Location) => LocationDescriptor)'
Then I checked in the official documentation they have provided state
for the same purpose.
So it worked like this,
<Link
to={{
pathname: "/my-path",
state: {
hello: "Hello World"
}
}}>
Press Me
</Link>
And in your next component you can get this value as following,
componentDidMount() {
console.log("received "+this.props.location.state.hello);
}
Make copy of an array
You can try using System.arraycopy()
int[] src = new int[]{1,2,3,4,5};
int[] dest = new int[5];
System.arraycopy( src, 0, dest, 0, src.length );
But, probably better to use clone() in most cases:
int[] src = ...
int[] dest = src.clone();
The view or its master was not found or no view engine supports the searched locations
I ran into this a while ago and it drove me crazy because it turned out to be simple. So within my View I was using a grid control that obtained data for the grid via an http request. Once the middle tier completed my request and returned the dataset, I received the same error. Turns out my return statement was 'return View(dataset);' instead of 'return Json(dataset);
Javascript call() & apply() vs bind()?
Imagine, bind is not available.
you can easily construct it as follow :
var someFunction=...
var objToBind=....
var bindHelper = function (someFunction, objToBind) {
return function() {
someFunction.apply( objToBind, arguments );
};
}
bindHelper(arguments);
React - How to force a function component to render?
The accepted answer is good.
Just to make it easier to understand.
Example component:
export default function MyComponent(props) {
const [updateView, setUpdateView] = useState(0);
return (
<>
<span style={{ display: "none" }}>{updateView}</span>
</>
);
}
To force re-rendering call the code below:
setUpdateView((updateView) => ++updateView);
jQuery's .on() method combined with the submit event
You need to delegate event to the document level
$(document).on('submit','form.remember',function(){
// code
});
$('form.remember').on('submit'
work same as $('form.remember').submit(
but when you use $(document).on('submit','form.remember'
then it will also work for the DOM added later.
In Spring MVC, how can I set the mime type header when using @ResponseBody
I would consider to refactor the service to return your domain object rather than JSON strings and let Spring handle the serialization (via the MappingJacksonHttpMessageConverter
as you write). As of Spring 3.1, the implementation looks quite neat:
@RequestMapping(produces = MediaType.APPLICATION_JSON_VALUE,
method = RequestMethod.GET
value = "/foo/bar")
@ResponseBody
public Bar fooBar(){
return myService.getBar();
}
Comments:
First, the <mvc:annotation-driven />
or the @EnableWebMvc
must be added to your application config.
Next, the produces attribute of the @RequestMapping
annotation is used to specify the content type of the response. Consequently, it should be set to MediaType.APPLICATION_JSON_VALUE (or "application/json"
).
Lastly, Jackson must be added so that any serialization and de-serialization between Java and JSON will be handled automatically by Spring (the Jackson dependency is detected by Spring and the MappingJacksonHttpMessageConverter
will be under the hood).
Find IP address of directly connected device
Your Best Approach is to install Wireshark, reboot the device wait for the TCP/UDP stream , broadcasts will announce the IP address for both Ethernet ports
This is especially useful when the device connected does not have DHCP Client enabled, then you can go from there.
nginx - nginx: [emerg] bind() to [::]:80 failed (98: Address already in use)
I use supervisor to run Nginx and Gunicorn side by side on a Docker container.
This was the configuration used for supervisor :
[supervisord]
nodaemon=true
[program:gunicorn]
command = /project/start.sh
user = www-data
[program:nginx]
command=/usr/sbin/nginx
The problem was how I launched Ngnix : by default it runs on the foreground. This makes supervise retry to run another instance of Nginx.
By adding -g 'daemon off;'
to the command line, Nginx stayed in the foreground, supervisor stopped trying to run another instance.
How do I add a submodule to a sub-directory?
I had a similar issue, but had painted myself into a corner with GUI tools.
I had a subproject with a few files in it that I had so far just copied around instead of checking into their own git repo. I created a repo in the subfolder, was able to commit, push, etc just fine. But in the parent repo the subfolder wasn't treated as a submodule, and its files were still being tracked by the parent repo - no good.
To get out of this mess I had to tell Git to stop tracking the subfolder (without deleting the files):
proj> git rm -r --cached ./ui/jslib
Then I had to tell it there was a submodule there (which you can't do if anything there is currently being tracked by git):
proj> git submodule add ./ui/jslib
Update
The ideal way to handle this involves a couple more steps. Ideally, the existing repo is moved out to its own directory, free of any parent git modules, committed and pushed, and then added as a submodule like:
proj> git submodule add [email protected]:user/jslib.git ui/jslib
That will clone the git repo in as a submodule - which involves the standard cloning steps, but also several other more obscure config steps that git takes on your behalf to get that submodule to work. The most important difference is that it places a simple .git file there, instead of a .git directory, which contains a path reference to where the real git dir lives - generally at parent project root .git/modules/jslib.
If you don't do things this way they'll work fine for you, but as soon as you commit and push the parent, and another dev goes to pull that parent, you just made their life a lot harder. It will be very difficult for them to replicate the structure you have on your machine so long as you have a full .git dir in a subfolder of a dir that contains its own .git dir.
So, move, push, git add submodule, is the cleanest option.
jQuery vs. javascript?
"I actually tried to had a normal objective discusssion over pros and
cons of 1., using framework over pure javascript and 2., jquery vs.
others, since jQuery seems to be easiest to work with with quickest
learning curve."
Using any framework because you don't want to actually learn the underlying language is absolutely wrong not only for JavaScript, but for any other programming language.
"Is there any reason (besides browser sniffing and personal "hate"
against John Resig) why jQuery is wrong?"
Most of the hate agains it comes from the exaggerated fanboyism which pollutes forums with "use jQuery" as an answer for every single JavaScript question and the overuse which produces code in which simple statements such as declaring a variable are done through library calls.
Nevertheless, there are also some legit technical issues such as the shared guilt in producing illegible code and overhead. Of course those two are aggravated by the lack of developer proficiency rather than the library itself.
How to make a UILabel clickable?
Swift 5
Similar to @liorco, but need to replace @objc with @IBAction.
class DetailViewController: UIViewController {
@IBOutlet weak var tripDetails: UILabel!
override func viewDidLoad() {
super.viewDidLoad()
...
let tap = UITapGestureRecognizer(target: self, action: #selector(DetailViewController.tapFunction))
tripDetails.isUserInteractionEnabled = true
tripDetails.addGestureRecognizer(tap)
}
@IBAction func tapFunction(sender: UITapGestureRecognizer) {
print("tap working")
}
}
This is working on Xcode 10.2.
Python Set Comprehension
You can get clean and clear solutions by building the appropriate predicates as helper functions. In other words, use the Python set-builder notation the same way you would write the answer with regular mathematics set-notation.
The whole idea behind set comprehensions is to let us write and reason in code the same way we do mathematics by hand.
With an appropriate predicate in hand, problem 1 simplifies to:
low_primes = {x for x in range(1, 100) if is_prime(x)}
And problem 2 simplifies to:
low_prime_pairs = {(x, x+2) for x in range(1,100,2) if is_prime(x) and is_prime(x+2)}
Note how this code is a direct translation of the problem specification, "A Prime Pair is a pair of consecutive odd numbers that are both prime."
P.S. I'm trying to give you the correct problem solving technique without actually giving away the answer to the homework problem.
$("#form1").validate is not a function
my solution to the problem:
in footer add <script src="//cdnjs.cloudflare.com/ajax/libs/jquery-form-validator/2.3.26/jquery.form-validator.min.js"></script>
How to access the first property of a Javascript object?
To get the first key name in the object you can use:
var obj = { first: 'someVal' };
Object.keys(obj)[0]; //returns 'first'
Returns a string, so you cant access nested objects if there were, like:
var obj = { first: { someVal : { id : 1} };
Here with that solution you can't access id.
The best solution if you want to get the actual object is using lodash like:
obj[_.first(_.keys(obj))].id
To return the value of the first key, (if you don't know exactly the first key name):
var obj = { first: 'someVal' };
obj[Object.keys(obj)[0]]; //returns 'someVal'
if you know the key name just use:
obj.first
or
obj['first']
How to set java.net.preferIPv4Stack=true at runtime?
I ran into this very problem trying to send mail with javax.mail from a web application in a web server running Java 7. Internal mail server destinations failed with "network unreachable", despite telnet and ping working from the same host, and while external mail servers worked. I tried
System.setProperty("java.net.preferIPv4Stack" , "true");
in the code, but that failed. So the parameter value was probably cached earlier by the system. Setting the VM argument
-Djava.net.preferIPv4Stack=true
in the web server startup script worked.
One further bit of evidence: in a very small targeted test program, setting the system property in the code did work. So the parameter is probably cached when the first Socket is used, probably not just as the JVM starts.
How do I format a number in Java?
public static void formatDouble(double myDouble){
NumberFormat numberFormatter = new DecimalFormat("##.000");
String result = numberFormatter.format(myDouble);
System.out.println(result);
}
For instance, if the double value passed into the formatDouble() method is 345.9372, the following will
be the result:
345.937
Similarly, if the value .7697 is passed to the method, the following will be the result:
.770
How do you comment out code in PowerShell?
There is a special way of inserting comments add the end of script:
....
exit
Hi
Hello
We are comments
And not executed
Anything after exit
is not executed, and behave quite like comments.
How to pass arguments within docker-compose?
This can now be done as of docker-compose v2+ as part of the build
object;
docker-compose.yml
version: '2'
services:
my_image_name:
build:
context: . #current dir as build context
args:
var1: 1
var2: c
See the docker compose docs.
In the above example "var1" and "var2" will be sent to the build environment.
Note: any env variables (specified by using the environment
block) which have the same name as args
variable(s) will override that variable.
Show Image View from file path?
Most of the answers are working but no one mentioned that the high resolution image will slow down the app , In my case i used images RecyclerView which was taking 0.9 GB of device memory In Just 30 Images.
I/Choreographer: Skipped 73 frames! The application may be doing too
much work on its main thread.
The solution is Sipmle you can degrade the quality like here : Reduce resolution of Bitmap
But I use Simple way , Glide handles the rest of work
fanContext?.let {
Glide.with(it)
.load(Uri.fromFile(File(item.filePath)))
.into(viewHolder.imagePreview)
}
Find nginx version?
Make sure that you have permissions to run the following commands.
If you check the man page of nginx from a terminal
man nginx
you can find this:
-V Print the nginx version, compiler version, and configure script parameters.
-v Print the nginx version.
Then type in terminal
nginx -v
nginx version: nginx/1.14.0
nginx -V
nginx version: nginx/1.14.0
built with OpenSSL 1.1.0g 2 Nov 2017
TLS SNI support enabled
If nginx is not installed in your system man nginx
command can not find man page, so make sure you have installed nginx.
You can also find the version using this command:
Use one of the command to find the path of nginx
ps aux | grep nginx
ps -ef | grep nginx
root 883 0.0 0.3 44524 3388 ? Ss Dec07 0:00 nginx: master process /usr/sbin/nginx -g daemon on; master_process on
Then run from terminal:
/usr/sbin/nginx -v
nginx version: nginx/1.14.0
javax.faces.application.ViewExpiredException: View could not be restored
I ran into this problem myself and realized that it was because of a side-effect of a Filter that I created which was filtering all requests on the appliation. As soon as I modified the filter to pick only certain requests, this problem did not occur. It maybe good to check for such filters in your application and see how they behave.
What is the HTML unicode character for a "tall" right chevron?
From the description and from the reference to the search box in the Ubuntu site, I gather that you actually want an arrowhead character pointing to the right. There are no Unicode characters designed to be used as arrowheads, but some of them may visually resemble an arrowhead.
In particular, if you draw your idea of the character at Shapecatcher.com, you will find many suggestions, such as “>” RIGHT-POINTING ANGLE BRACKET' (U+232A) and “?” MEDIUM RIGHT-POINTING ANGLE BRACKET ORNAMENT (U+276D).
Such characters generally have limited support in fonts, so you would need to carefully write a longish font-family
list or to use a downloadable font. See my Guide to using special characters in HTML.
Especially if the intended use is as a symbol in a search box, as the reference to the Ubuntu page suggests, it is questionable whether you should use a character at all. It’s not really an element of text here; rather, a graphic symbol that accompanies text but isn’t a part of it. So why take all the trouble with using a character (safely), when it isn’t really a character?
How do I get Flask to run on port 80?
Easiest and Best Solution
Save your .py file in a folder. This case my folder name is test. In the command prompt run the following
c:\test> set FLASK_APP=application.py
c:\test> set FLASK_RUN_PORT=8000
c:\test> flask run
----------------- Following will be returned ----------------
* Serving Flask app "application.py"
* Environment: production
WARNING: Do not use the development server in a production environment.
Use a production WSGI server instead.
* Debug mode: off
* Running on http://127.0.0.1:8000/ (Press CTRL+C to quit)
127.0.0.1 - - [23/Aug/2019 09:40:04] "[37mGET / HTTP/1.1[0m" 200 -
127.0.0.1 - - [23/Aug/2019 09:40:04] "[33mGET /favicon.ico HTTP/1.1[0m" 404 -
Now on your browser type: http://127.0.0.1:8000. Thanks
java SSL and cert keystore
SSL properties are set at the JVM level via system properties. Meaning you can either set them when you run the program (java -D....) Or you can set them in code by doing System.setProperty.
The specific keys you have to set are below:
javax.net.ssl.keyStore- Location of
the Java keystore file containing an
application process's own certificate
and private key. On Windows, the
specified pathname must use forward
slashes, /, in place of backslashes.
javax.net.ssl.keyStorePassword - Password
to access the private key from the
keystore file specified by
javax.net.ssl.keyStore. This password
is used twice: To unlock the keystore
file (store password), and To decrypt
the private key stored in the keystore
(key password).
javax.net.ssl.trustStore - Location of
the Java keystore file containing the
collection of CA certificates trusted
by this application process (trust
store). On Windows, the specified
pathname must use forward slashes, /
,
in place of backslashes, \
.
If a trust store location is not
specified using this property, the
SunJSSE implementation searches for
and uses a keystore file in the
following locations (in order):
$JAVA_HOME/lib/security/jssecacerts
$JAVA_HOME/lib/security/cacerts
javax.net.ssl.trustStorePassword -
Password to unlock the keystore file
(store password) specified by
javax.net.ssl.trustStore
.
javax.net.ssl.trustStoreType - (Optional)
For Java keystore file format, this
property has the value jks (or JKS).
You do not normally specify this
property, because its default value is
already jks.
javax.net.debug - To switch
on logging for the SSL/TLS layer, set
this property to ssl.
Is SQL syntax case sensitive?
Identifiers and reserved words should not be case sensitive, although many follow a convention to use capitals for reserved words and Pascal case for identifiers.
See SQL-92 Sec. 5.2
How to make FileFilter in java?
Try something like this...
String yourPath = "insert here your path..";
File directory = new File(yourPath);
String[] myFiles = directory.list(new FilenameFilter() {
public boolean accept(File directory, String fileName) {
return fileName.endsWith(".txt");
}
});
How to read and write xml files?
Writing XML using JAXB (Java Architecture for XML Binding):
http://www.mkyong.com/java/jaxb-hello-world-example/
package com.mkyong.core;
import javax.xml.bind.annotation.XmlAttribute;
import javax.xml.bind.annotation.XmlElement;
import javax.xml.bind.annotation.XmlRootElement;
@XmlRootElement
public class Customer {
String name;
int age;
int id;
public String getName() {
return name;
}
@XmlElement
public void setName(String name) {
this.name = name;
}
public int getAge() {
return age;
}
@XmlElement
public void setAge(int age) {
this.age = age;
}
public int getId() {
return id;
}
@XmlAttribute
public void setId(int id) {
this.id = id;
}
}
package com.mkyong.core;
import java.io.File;
import javax.xml.bind.JAXBContext;
import javax.xml.bind.JAXBException;
import javax.xml.bind.Marshaller;
public class JAXBExample {
public static void main(String[] args) {
Customer customer = new Customer();
customer.setId(100);
customer.setName("mkyong");
customer.setAge(29);
try {
File file = new File("C:\\file.xml");
JAXBContext jaxbContext = JAXBContext.newInstance(Customer.class);
Marshaller jaxbMarshaller = jaxbContext.createMarshaller();
// output pretty printed
jaxbMarshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);
jaxbMarshaller.marshal(customer, file);
jaxbMarshaller.marshal(customer, System.out);
} catch (JAXBException e) {
e.printStackTrace();
}
}
}
How to open, read, and write from serial port in C?
I wrote this a long time ago (from years 1985-1992, with just a few tweaks since then), and just copy and paste the bits needed into each project.
You must call cfmakeraw
on a tty
obtained from tcgetattr
. You cannot zero-out a struct termios
, configure it, and then set the tty
with tcsetattr
. If you use the zero-out method, then you will experience unexplained intermittent failures, especially on the BSDs and OS X. "Unexplained intermittent failures" include hanging in read(3)
.
#include <errno.h>
#include <fcntl.h>
#include <string.h>
#include <termios.h>
#include <unistd.h>
int
set_interface_attribs (int fd, int speed, int parity)
{
struct termios tty;
if (tcgetattr (fd, &tty) != 0)
{
error_message ("error %d from tcgetattr", errno);
return -1;
}
cfsetospeed (&tty, speed);
cfsetispeed (&tty, speed);
tty.c_cflag = (tty.c_cflag & ~CSIZE) | CS8; // 8-bit chars
// disable IGNBRK for mismatched speed tests; otherwise receive break
// as \000 chars
tty.c_iflag &= ~IGNBRK; // disable break processing
tty.c_lflag = 0; // no signaling chars, no echo,
// no canonical processing
tty.c_oflag = 0; // no remapping, no delays
tty.c_cc[VMIN] = 0; // read doesn't block
tty.c_cc[VTIME] = 5; // 0.5 seconds read timeout
tty.c_iflag &= ~(IXON | IXOFF | IXANY); // shut off xon/xoff ctrl
tty.c_cflag |= (CLOCAL | CREAD);// ignore modem controls,
// enable reading
tty.c_cflag &= ~(PARENB | PARODD); // shut off parity
tty.c_cflag |= parity;
tty.c_cflag &= ~CSTOPB;
tty.c_cflag &= ~CRTSCTS;
if (tcsetattr (fd, TCSANOW, &tty) != 0)
{
error_message ("error %d from tcsetattr", errno);
return -1;
}
return 0;
}
void
set_blocking (int fd, int should_block)
{
struct termios tty;
memset (&tty, 0, sizeof tty);
if (tcgetattr (fd, &tty) != 0)
{
error_message ("error %d from tggetattr", errno);
return;
}
tty.c_cc[VMIN] = should_block ? 1 : 0;
tty.c_cc[VTIME] = 5; // 0.5 seconds read timeout
if (tcsetattr (fd, TCSANOW, &tty) != 0)
error_message ("error %d setting term attributes", errno);
}
...
char *portname = "/dev/ttyUSB1"
...
int fd = open (portname, O_RDWR | O_NOCTTY | O_SYNC);
if (fd < 0)
{
error_message ("error %d opening %s: %s", errno, portname, strerror (errno));
return;
}
set_interface_attribs (fd, B115200, 0); // set speed to 115,200 bps, 8n1 (no parity)
set_blocking (fd, 0); // set no blocking
write (fd, "hello!\n", 7); // send 7 character greeting
usleep ((7 + 25) * 100); // sleep enough to transmit the 7 plus
// receive 25: approx 100 uS per char transmit
char buf [100];
int n = read (fd, buf, sizeof buf); // read up to 100 characters if ready to read
The values for speed are B115200
, B230400
, B9600
, B19200
, B38400
, B57600
, B1200
, B2400
, B4800
, etc. The values for parity are 0
(meaning no parity), PARENB|PARODD
(enable parity and use odd), PARENB
(enable parity and use even), PARENB|PARODD|CMSPAR
(mark parity), and PARENB|CMSPAR
(space parity).
"Blocking" sets whether a read()
on the port waits for the specified number of characters to arrive. Setting no blocking means that a read()
returns however many characters are available without waiting for more, up to the buffer limit.
Addendum:
CMSPAR
is needed only for choosing mark and space parity, which is uncommon. For most applications, it can be omitted. My header file /usr/include/bits/termios.h
enables definition of CMSPAR
only if the preprocessor symbol __USE_MISC
is defined. That definition occurs (in features.h
) with
#if defined _BSD_SOURCE || defined _SVID_SOURCE
#define __USE_MISC 1
#endif
The introductory comments of <features.h>
says:
/* These are defined by the user (or the compiler)
to specify the desired environment:
...
_BSD_SOURCE ISO C, POSIX, and 4.3BSD things.
_SVID_SOURCE ISO C, POSIX, and SVID things.
...
*/
How to preSelect an html dropdown list with php?
I have 2 php files and i made this, and it works.
(this is an example) the first code is from the one file and the second code from two file.
<form action="two.php" method="post">
<input type="submit" class="button" value="submit" name="one"/>
<select name="numbers">
<option value="1"> 1 </option>
<option value="2"> 2 </option>
<option value="3"> 3 </option>
</select>
</form>
if(isset ($_POST['one']))
{
if($_POST['numbers']=='1')
{
$a='1' ;
}
else if($_POST['numbers']=='2')
{
$a='2' ;
{
else if ($_POST['numbers']=='3')
{
$a='3' ;
}
}
How to check if the string is empty?
Below is a simple method to identify an empty string:
a="" #Empty string
if(len(a)==0): #len() is used to find the length of the string or variable inside its' brackets.
print("Empty")
else:
print("Filled")
The above len() method is an inbuilt function that helps us to find the length of a certain string or variable. It can also be used in the case of lists.
LOGIC: If the length of the character or variable is 0 then absolutely it means that the string or variable is empty. BUT remember that this will work only in the case of strings and lists and not with integers. Below is the code to find length of integers.
a=int(input())
if(len(str(a))==0):
print(True)
In the above code str() is used to convert an int to a string format like from 123 to its string format "123". In the string format it will be valid.
Adding script tag to React/JSX
componentDidMount() {
const head = document.querySelector("head");
const script = document.createElement("script");
script.setAttribute(
"src",
"https://assets.calendly.com/assets/external/widget.js"
);
head.appendChild(script);
}
button image as form input submit button?
<div class="container-fluid login-container">
<div class="row">
<form (ngSubmit)="login('da')">
<div class="col-md-4">
<div class="login-text">
Login
</div>
<div class="form-signin">
<input type="text" class="form-control" placeholder="Email" required>
<input type="password" class="form-control" placeholder="Password" required>
</div>
</div>
<div class="col-md-4">
<div class="login-go-div">
<input type="image" src="../../../assets/images/svg/login-go-initial.svg" class="login-go"
onmouseover="this.src='../../../assets/images/svg/login-go.svg'"
onmouseout="this.src='../../../assets/images/svg/login-go-initial.svg'"/>
</div>
</div>
</form>
</div>
</div>
This is the working code for it.
Windows batch script to move files
move c:\Sourcefoldernam\*.* e:\destinationFolder
^ This did not work for me for some reason
But when I tried using quotation marks, it suddenly worked:
move "c:\Sourcefoldernam\*.*" "e:\destinationFolder"
I think its because my directory had spaces in one of the folders. So if it doesn't work for you, try with quotation marks!
How do you tell if caps lock is on using JavaScript?
When you type, if caplock is on, it could automatically convert the current char to lowercase. That way even if caplocks is on, it will not behave like it is on the current page. To inform your users you could display a text saying that caplocks is on, but that the form entries are converted.
VBA, if a string contains a certain letter
Not sure if this is what you're after, but it will loop through the range that you gave it and if it finds an "A" it will remove it from the cell. I'm not sure what oldStr is used for...
Private Sub foo()
Dim myString As String
RowCount = WorksheetFunction.CountA(Range("A:A"))
For i = 2 To RowCount
myString = Trim(Cells(i, 1).Value)
If InStr(myString, "A") > 0 Then
Cells(i, 1).Value = Left(myString, InStr(myString, "A"))
End If
Next
End Sub
How to prevent the "Confirm Form Resubmission" dialog?
After processing the POST page, redirect the user to the same page.
On
http://test.com/test.php
header('Location: http://test.com/test.php');
This will get rid of the box, as refreshing the page will not resubmit the data.
Python - Passing a function into another function
For passing both a function, and any arguments to the function:
from typing import Callable
def looper(fn: Callable, n:int, *args, **kwargs):
"""
Call a function `n` times
Parameters
----------
fn: Callable
Function to be called.
n: int
Number of times to call `func`.
*args
Positional arguments to be passed to `func`.
**kwargs
Keyword arguments to be passed to `func`.
Example
-------
>>> def foo(a:Union[float, int], b:Union[float, int]):
... '''The function to pass'''
... print(a+b)
>>> looper(foo, 3, 2, b=4)
6
6
6
"""
for i in range(n):
fn(*args, **kwargs)
Depending on what you are doing, it could make sense to define a decorator
, or perhaps use functools.partial
.
Best way to move files between S3 buckets?
If you have a unix host within AWS, then use s3cmd from s3tools.org. Set up permissions so that your key as read access to your development bucket. Then run:
s3cmd cp -r s3://productionbucket/feed/feedname/date s3://developmentbucket/feed/feedname
ORA-12170: TNS:Connect timeout occurred
I have tried changing the tnsnames.ora file putting the IP of the server instead of localhost or loopback address, it did not work. The firewall was blocking the requests. Please configure your firewall or turn it off(not recommended), it would work.
Unable to load DLL (Module could not be found HRESULT: 0x8007007E)
There is one very funny thing (and has a technical relevance) which might waste your hours so thought of sharing it here -
I created a console application project ConsoleApplication1
and a class library project ClassLibrary1
.
All the code which was making the p/invoke was present in ClassLibrary1.dll
. So before debugging the application from visual studio I simply copied the C++ unmanaged assembly (myUnmanagedFunctions.dll
) into the \bin\debug\
directory of ClassLibrary1
project so that it can be loaded at run-time by the CLR.
I kept getting the
Unable to load DLL
error for hours. Later on I realized that all such unmanaged assemblies which are to be loaded need to be copied into the \bin\debug
directory of the start-up project ConsoleApplication1
which is usually a win form, console or web application.
So please be cautious the Current Directory
in the accepted answer actually means Current Directory
of main executable from where you application process is starting. Looks like an obvious thing but might not be so at times.
Lesson Learnt - Always place the unamanaged dlls in the same directory as the start-up executable to ensure that it can be found.
Cycles in an Undirected Graph
A connected, undirected graph G that has no cycles is a tree! Any tree has exactly n - 1 edges, so we can simply traverse the edge list of the graph and count the edges. If we count n - 1 edges then we return “yes” but if we reach the nth edge then we return “no”. This takes O (n) time because we look at at most n edges.
But if the graph is not connected,then we would have to use DFS. We can traverse through the edges and if any unexplored edges lead to the visited vertex then it has cycle.
What is the difference between required and ng-required?
AngularJS form elements look for the required
attribute to perform validation functions. ng-required
allows you to set the required
attribute depending on a boolean test (for instance, only require field B - say, a student number - if the field A has a certain value - if you selected "student" as a choice)
As an example, <input required>
and <input ng-required="true">
are essentially the same thing
If you are wondering why this is this way, (and not just make <input required="true">
or <input required="false">
), it is due to the limitations of HTML - the required
attribute has no associated value - its mere presence means (as per HTML standards) that the element is required - so angular needs a way to set/unset required value (required="false"
would be invalid HTML)
Entity Framework 5 Updating a Record
There are some really good answers given already, but I wanted to throw in my two cents. Here is a very simple way to convert a view object into a entity. The simple idea is that only the properties that exist in the view model get written to the entity. This is similar to @Anik Islam Abhi's answer, but has null propagation.
public static T MapVMUpdate<T>(object updatedVM, T original)
{
PropertyInfo[] originalProps = original.GetType().GetProperties();
PropertyInfo[] vmProps = updatedVM.GetType().GetProperties();
foreach (PropertyInfo prop in vmProps)
{
PropertyInfo projectProp = originalProps.FirstOrDefault(x => x.Name == prop.Name);
if (projectProp != null)
{
projectProp.SetValue(original, prop.GetValue(updatedVM));
}
}
return original;
}
Pros
- Views don't need to have all the properties of the entity.
- You never have to update code when you add remove a property to a view.
- Completely generic
Cons
- 2 hits on the database, one to load the original entity, and one to save it.
To me the simplicity and low maintenance requirements of this approach outweigh the added database call.
Calling a function in jQuery with click()
$("#closeLink").click(closeIt);
Let's say you want to call your function passing some args to it i.e., closeIt(1, false)
. Then, you should build an anonymous function and call closeIt
from it.
$("#closeLink").click(function() {
closeIt(1, false);
});
how to get current datetime in SQL?
GETDATE()
or GETUTCDATE()
are now superseded by the richer SYSDATETIME
, SYSUTCDATETIME
, and SYSDATETIMEOFFSET
(in SQL 2008)
- Yes, I don't think
ANSI
has ever declared anything, and so each manufacturer has their own.
- That would be
NOW()
Hope this helps...
Rob
Android: How to Enable/Disable Wifi or Internet Connection Programmatically
Android 10 (Q) onwards wifi can not be enabled/disabled you need to open the setting intent,
// for android Q and above
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.Q) {
Intent panelIntent = new
Intent(Settings.Panel.ACTION_INTERNET_CONNECTIVITY);
startActivityForResult(panelIntent, 0);
} else {
// for previous android version
WifiManager wifiManager = (WifiManager)
this.getApplicationContext().getSystemService(WIFI_SERVICE);
wifiManager.setWifiEnabled(true);
}
In manifest,
<uses-permission
android:name="android.permission.CHANGE_WIFI_STATE"
android:required="true" />
iPhone and WireShark
The easiest way of doing this will be to use wifi of course. You will need to determine if your wifi base acts as a hub or a switch. If it acts as a hub then just connect your windows pc to it and wireshark should be able to see all the traffic from the iPhone. If it is a switch then your easiest bet will be to buy a cheap hub and connect the wan side of your wifi base to the hub and then connect your windows pc running wireshark to the hub as well. At that point wireshark will be able to see all the traffic as it passes over the hub.
SQL Server: Attach incorrect version 661
SQL Server 2008 databases are version 655. SQL Server 2008 R2 databases are 661. You are trying to attach an 2008 R2 database (v. 661) to an 2008 instance and this is not supported. Once the database has been upgraded to an 2008 R2 version, it cannot be downgraded. You'll have to either upgrade your 2008 SP2 instance to R2, or you have to copy out the data in that database into an 2008 database (eg using the data migration wizard, or something equivalent).
The message is misleading, to say the least, it says 662 because SQL Server 2008 SP2 does support 662 as a database version, this is when 15000 partitions are enabled in the database, see Support for 15000 Partitions.docx. Enabling the support bumps the DB version to 662, disabling it moves it back to 655. But SQL Server 2008 SP2 does not support 661 (the R2 version).
How to make a GUI for bash scripts?
Please, take a look at my library:
http://sites.google.com/site/easybashgui
It is intended to handle, with the same commands set, indifferently all four big tools "kdialog", "Xdialog", "cdialog" and "zenity", depending if X is running or not, if D.E. is KDE or Gnome or other. There are 15 different functions ( among them there are two called "progress" and "adjust" )...
Bye
:-)
Using Spring 3 autowire in a standalone Java application
A nice solution would be to do following,
import org.springframework.beans.BeansException;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.stereotype.Component;
@Component
public class SpringContext implements ApplicationContextAware {
private static ApplicationContext context;
/**
* Returns the Spring managed bean instance of the given class type if it exists.
* Returns null otherwise.
* @param beanClass
* @return
*/
public static <T extends Object> T getBean(Class<T> beanClass) {
return context.getBean(beanClass);
}
@Override
public void setApplicationContext(ApplicationContext context) throws BeansException {
// store ApplicationContext reference to access required beans later on
SpringContext.context = context;
}
}
Then you can use it like:
YourClass yourClass = SpringContext.getBean(YourClass.class);
I found this very nice solution in the following website: https://confluence.jaytaala.com/pages/viewpage.action?pageId=18579463
python 2.7: cannot pip on windows "bash: pip: command not found"
The problem is that your Python version and the library you want to use are not same versionally (Python). Even if you install Python's latest version, your PATH might not change properly and automatically. Thus, you should change it manually.After matching their version, it will work.
Ex: When I tried to install Django3, I got same error. I noticed that my PATH still seems C:\python27\Scripts though I already install Python3.8, so that I manually edited my PATH C:\python38\Scripts and reinstalled pip install Django and everything worked well.
Convert comma separated string of ints to int array
This is for longs, but you can modify it easily to work with ints.
private static long[] ConvertStringArrayToLongArray(string str)
{
return str.Split(",".ToCharArray()).Select(x => long.Parse(x.ToString())).ToArray();
}
How to remove pip package after deleting it manually
I met the same issue while experimenting with my own Python library and what I've found out is that pip freeze
will show you the library as installed if your current directory contains lib.egg-info
folder. And pip uninstall <lib>
will give you the same error message.
- Make sure your current directory doesn't have any
egg-info
folders
- Check
pip show <lib-name>
to see the details about the location of the library, so you can remove files manually.
What does "SyntaxError: Missing parentheses in call to 'print'" mean in Python?
If your code should work in both Python 2 and 3, you can achieve this by loading this at the beginning of your program:
from __future__ import print_function # If code has to work in Python 2 and 3!
Then you can print in the Python 3 way:
print("python")
If you want to print something without creating a new line - you can do this:
for number in range(0, 10):
print(number, end=', ')
Parse HTML in Android
Have you tried using Html.fromHtml(source)?
I think that class is pretty liberal with respect to source quality (it uses TagSoup internally, which was designed with real-life, bad HTML in mind). It doesn't support all HTML tags though, but it does come with a handler you can implement to react on tags it doesn't understand.
Maven Unable to locate the Javac Compiler in:
None of the current answers helped me here. We were getting something like:
[ERROR] Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:
#.#.#:compile (default-compile) on project Streaming_Test: Compilation failure
[ERROR] Unable to locate the Javac Compiler in:
[ERROR] /opt/java/J7.0/../lib/tools.jar
This happens because the Java installation has determined that it is a JRE installation. It's expecting there to be JDK stuff above the JRE subdirectory, hence the ../lib
in the path. Our tools.jar
is in $JAVA_HOME/lib/tools.jar
not in $JAVA_HOME/../lib/tools.jar
.
Unfortunately, we do not have an option to install a JDK on our OS (don't ask) so that wasn't an option. I fixed the problem by adding the following to the maven pom.xml
:
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<configuration>
<fork>true</fork> <!-- not sure if this is also needed -->
<executable>${JAVA_HOME}/bin/javac</executable>
<!-- ^^^^^^^^^^^^^^^^^^^^^^ -->
</configuration>
</plugin>
By pointing the executable to the right place this at least got past our compilation failures.
How to add a new row to datagridview programmatically
string[] splited = t.Split('>');
int index = dgv_customers.Rows.Add(new DataGridViewRow());
dgv_customers.Rows[index].Cells["cust_id"].Value=splited.WhichIsType("id;");
But be aware, WhichIsType
is the extension method I created.
C++ Structure Initialization
I might be missing something here, by why not:
#include <cstdio>
struct Group {
int x;
int y;
const char* s;
};
int main()
{
Group group {
.x = 1,
.y = 2,
.s = "Hello it works"
};
printf("%d, %d, %s", group.x, group.y, group.s);
}
Logical operator in a handlebars.js {{#if}} conditional
Correct Solution for AND/OR
Handlebars.registerHelper('and', function () {
// Get function args and remove last one (function name)
return Array.prototype.slice.call(arguments, 0, arguments.length - 1).every(Boolean);
});
Handlebars.registerHelper('or', function () {
// Get function args and remove last one (function name)
return Array.prototype.slice.call(arguments, 0, arguments.length - 1).some(Boolean);
});
Then call as follows
{{#if (or (eq questionType 'STARTTIME') (eq questionType 'ENDTIME') (..) ) }}
BTW: Note that the solution given here is incorrect, he's not subtracting the last argument which is the function name.
https://stackoverflow.com/a/31632215/1005607
His original AND/OR was based on the full list of arguments
and: function () {
return Array.prototype.slice.call(arguments).every(Boolean);
},
or: function () {
return Array.prototype.slice.call(arguments).some(Boolean);
}
Can someone change that answer? I just wasted an hour trying to fix something in an answer recommended by 86 people. The fix is to filter out the last argument which is the function name. Array.prototype.slice.call(arguments, 0, arguments.length - 1)
How to access Session variables and set them in javascript?
This is a cheat, but you can do this, send the value to sever side as a parameter
<script>
var myVar = "hello"
window.location.href = window.location.href.replace(/[\?#].*|$/, "?param=" + myVar); //Send the variable to the server side
</script>
And from the server side, retrieve the parameter
string myVar = Request.QueryString["param"];
Session["SessionName"] = myVar;
hope this helps
How to run PowerShell in CMD
You need to separate the arguments from the file path:
powershell.exe -noexit "& 'D:\Work\SQLExecutor.ps1 ' -gettedServerName 'MY-PC'"
Another option that may ease the syntax using the File parameter and positional parameters:
powershell.exe -noexit -file "D:\Work\SQLExecutor.ps1" "MY-PC"
How to move or copy files listed by 'find' command in unix?
Actually, you can process the find
command output in a copy command in two ways:
If the find
command's output doesn't contain any space, i.e if the filename doesn't contain a space in it, then you can use:
Syntax:
find <Path> <Conditions> | xargs cp -t <copy file path>
Example:
find -mtime -1 -type f | xargs cp -t inner/
But our production data files might contain spaces, so most of time this command is effective:
Syntax:
find <path> <condition> -exec cp '{}' <copy path> \;
Example
find -mtime -1 -type f -exec cp '{}' inner/ \;
In the second example, the last part, the semi-colon is also considered as part of the find
command, and should be escaped before pressing Enter. Otherwise you will get an error something like:
find: missing argument to `-exec'
How to do logging in React Native?
console.log() is the easy way to debug your code but it need to be use with arrow function or bind() while displaying any state. You may find the link useful.
Makefile, header dependencies
A slightly modified version of Sophie's answer which allows to output the *.d files to a different folder (I will only paste the interesting part that generates the dependency files):
$(OBJDIR)/%.o: %.cpp
# Generate dependency file
mkdir -p $(@D:$(OBJDIR)%=$(DEPDIR)%)
$(CXX) $(CXXFLAGS) $(CPPFLAGS) -MM -MT $@ $< -MF $(@:$(OBJDIR)/%.o=$(DEPDIR)/%.d)
# Generate object file
mkdir -p $(@D)
$(CXX) $(CXXFLAGS) $(CPPFLAGS) -c $< -o $@
Note that the parameter
-MT $@
is used to ensure that the targets (i.e. the object file names) in the generated *.d files contain the full path to the *.o files and not just the file name.
I don't know why this parameter is NOT needed when using -MMD in combination with -c (as in Sophie's version). In this combination it seems to write the full path of the *.o files into the *.d files. Without this combination, -MMD also writes only the pure file names without any directory components into the *.d files. Maybe somebody knows why -MMD writes the full path when combined with -c. I have not found any hint in the g++ man page.
What is the difference between concurrency and parallelism?
Parallelism is simultaneous execution of processes on a multiple cores per CPU
or multiple CPUs (on a single motherboard)
.
Concurrency is when Parallelism is achieved on a single core/CPU
by using scheduling algorithms that divides the CPU’s time (time-slice). Processes are interleaved.
Units:
- 1 or many cores in a single CPU (pretty much all modern day processors)
- 1 or many CPUs on a motherboard (think old school servers)
- 1 application is 1 program (think Chrome browser)
- 1 program can have 1 or many processes (think each Chrome browser tab is a process)
- 1 process can have 1 or many threads from 1 program (Chrome tab playing Youtube video in 1 thread, another thread spawned for comments
section, another for users login info)
- Thus, 1 program can have 1 or many threads of execution
- 1 process is
thread(s)+allocated memory resources by OS
(heap, registers, stack, class memory)
How to pass values between Fragments
Communicating between fragments is fairly complicated (I find the listeners concept a little challenging to implement).
It is common to use a 'Event Bus" to abstract these communications. This is a 3rd party library that takes care of this communication for you.
'Otto' is one that is used often to do this, and might be worth looking into: http://square.github.io/otto/
Where can I set path to make.exe on Windows?
Why don't you create a bat file makedos.bat
containing the following line?
c:\DOS\make.exe %1 %2 %5
and put it in C:\DOS
(or C:\Windows
è or make sure that it is in your %path%
)
You can run from cmd, SET and it displays all environment variables, including PATH.
In registry you can find environment variables under:
HKEY_CURRENT_USER\Environment
HKEY_CURRENT_USER\Volatile Environment
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\Session Manager\Environment
Check if element found in array c++
You can do it in a beginners style by using control statements and loops..
#include <iostream>
using namespace std;
int main(){
int arr[] = {10,20,30,40,50}, toFind= 10, notFound = -1;
for(int i = 0; i<=sizeof(arr); i++){
if(arr[i] == toFind){
cout<< "Element is found at " <<i <<" index" <<endl;
return 0;
}
}
cout<<notFound<<endl;
}
How do I add an element to a list in Groovy?
From the documentation:
We can add to a list in many ways:
assert [1,2] + 3 + [4,5] + 6 == [1, 2, 3, 4, 5, 6]
assert [1,2].plus(3).plus([4,5]).plus(6) == [1, 2, 3, 4, 5, 6]
//equivalent method for +
def a= [1,2,3]; a += 4; a += [5,6]; assert a == [1,2,3,4,5,6]
assert [1, *[222, 333], 456] == [1, 222, 333, 456]
assert [ *[1,2,3] ] == [1,2,3]
assert [ 1, [2,3,[4,5],6], 7, [8,9] ].flatten() == [1, 2, 3, 4, 5, 6, 7, 8, 9]
def list= [1,2]
list.add(3) //alternative method name
list.addAll([5,4]) //alternative method name
assert list == [1,2,3,5,4]
list= [1,2]
list.add(1,3) //add 3 just before index 1
assert list == [1,3,2]
list.addAll(2,[5,4]) //add [5,4] just before index 2
assert list == [1,3,5,4,2]
list = ['a', 'b', 'z', 'e', 'u', 'v', 'g']
list[8] = 'x'
assert list == ['a', 'b', 'z', 'e', 'u', 'v', 'g', null, 'x']
You can also do:
def myNewList = myList << "fifth"
WPF Datagrid set selected row
It's a little trickier to do what you're trying to do than I'd prefer, but that's because you don't really directly bind a DataGrid
to a DataTable
.
When you bind DataGrid.ItemsSource
to a DataTable
, you're really binding it to the default DataView
, not to the table itself. This is why, for instance, you don't have to do anything to make a DataGrid
sort rows when you click on a column header - that functionality's baked into DataView
, and DataGrid
knows how to access it (through the IBindingList
interface).
The DataView
implements IEnumerable<DataRowView>
(more or less), and the DataGrid
fills its items by iterating over this. This means that when you've bound DataGrid.ItemsSource
to a DataTable
, its SelectedItem
property will be a DataRowView
, not a DataRow
.
If you know all this, it's pretty straightforward to build a wrapper class that lets you expose properties that you can bind to. There are three key properties:
Table
, the DataTable
,
Row
, a two-way bindable property of type DataRowView
, and
SearchText
, a string property that, when it's set, will find the first matching DataRowView
in the table's default view, set the Row
property, and raise PropertyChanged
.
It looks like this:
public class DataTableWrapper : INotifyPropertyChanged
{
private DataRowView _Row;
private string _SearchText;
public DataTableWrapper()
{
// using a parameterless constructor lets you create it directly in XAML
DataTable t = new DataTable();
t.Columns.Add("id", typeof (int));
t.Columns.Add("text", typeof (string));
// let's acquire some sample data
t.Rows.Add(new object[] { 1, "Tower"});
t.Rows.Add(new object[] { 2, "Luxor" });
t.Rows.Add(new object[] { 3, "American" });
t.Rows.Add(new object[] { 4, "Festival" });
t.Rows.Add(new object[] { 5, "Worldwide" });
t.Rows.Add(new object[] { 6, "Continental" });
t.Rows.Add(new object[] { 7, "Imperial" });
Table = t;
}
// you should have this defined as a code snippet if you work with WPF
private void OnPropertyChanged(string propertyName)
{
PropertyChangedEventHandler h = PropertyChanged;
if (h != null)
{
h(this, new PropertyChangedEventArgs(propertyName));
}
}
public event PropertyChangedEventHandler PropertyChanged;
// SelectedItem gets bound to this two-way
public DataRowView Row
{
get { return _Row; }
set
{
if (_Row != value)
{
_Row = value;
OnPropertyChanged("Row");
}
}
}
// the search TextBox is bound two-way to this
public string SearchText
{
get { return _SearchText; }
set
{
if (_SearchText != value)
{
_SearchText = value;
Row = Table.DefaultView.OfType<DataRowView>()
.Where(x => x.Row.Field<string>("text").Contains(_SearchText))
.FirstOrDefault();
}
}
}
public DataTable Table { get; private set; }
}
And here's XAML that uses it:
<Window x:Class="DataGridSelectionDemo.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:dg="clr-namespace:Microsoft.Windows.Controls;assembly=WPFToolkit"
xmlns:DataGridSelectionDemo="clr-namespace:DataGridSelectionDemo"
Title="DataGrid selection demo"
Height="350"
Width="525">
<Window.DataContext>
<DataGridSelectionDemo:DataTableWrapper />
</Window.DataContext>
<DockPanel>
<Grid DockPanel.Dock="Top">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto" />
<ColumnDefinition Width="*" />
</Grid.ColumnDefinitions>
<Label>Text</Label>
<TextBox Grid.Column="1"
Text="{Binding SearchText, Mode=TwoWay}" />
</Grid>
<dg:DataGrid DockPanel.Dock="Top"
ItemsSource="{Binding Table}"
SelectedItem="{Binding Row, Mode=TwoWay}" />
</DockPanel>
</Window>
using wildcards in LDAP search filters/queries
This should work, at least according to the Search Filter Syntax article on MSDN network.
The "hang-up" you have noticed is probably just a delay. Try running the same query with narrower scope (for example the specific OU where the test object is located), as it may take very long time for processing if you run it against all AD objects.
You may also try separating the filter into two parts:
(|(displayName=*searchstring)(displayName=searchstring*))
angular.js ng-repeat li items with html content
ng-bind-html-unsafe is deprecated from 1.2. The correct answer should be currently:
HTML-side: (the same as the accepted answer stated):
<div ng-app ng-controller="MyCtrl">
<ul>
<li ng-repeat=" opt in opts" ng-bind-html-unsafe="opt.text">
{{ opt.text }}
</li>
</ul>
<p>{{opt}}</p>
</div>
But in the controller-side:
myApp.controller('myCtrl', ['$scope', '$sce', function($scope, $sce) {
// ...
$scope.opts.map(function(opt) {
opt = $sce.trustAsHtml(opt);
});
}
grep a tab in UNIX
Look for blank spaces many times [[:space:]]*
grep [[:space:]]*'.''.'
Will find something like this:
'the tab' ..
These are single quotations ('), and not double (").
This is how you make concatenation in grep. =-)
shell init issue when click tab, what's wrong with getcwd?
This usually occurs when your current directory does not exist anymore. Most likely, from another terminal you remove that directory (from within a script or whatever). To get rid of this, in case your current directory was recreated in the meantime, just cd
to another (existing) directory and then cd
back; the simplest would be: cd; cd -
.
SOAP client in .NET - references or examples?
Prerequisites: You already have the service and published WSDL file, and you want to call your web service from C# client application.
There are 2 main way of doing this:
A) ASP.NET services, which is old way of doing SOA
B) WCF, as John suggested, which is the latest framework from MS and provides many protocols, including open and MS proprietary ones.
Adding a service reference step by step
The simplest way is to generate proxy classes in C# application (this process is called adding service reference).
- Open your project (or create a new one) in visual studio
- Right click on the project (on the project and not the solution) in Solution Explorer and click Add Service Reference
A dialog should appear shown in screenshot below. Enter the url of your wsdl file and hit Ok. Note that if you'll receive error message after hitting ok, try removing ?wsdl part from url.
I'm using http://www.dneonline.com/calculator.asmx?WSDL as an example
Expand Service References in Solution Explorer and double click CalculatorServiceReference
(or whatever you named the named the service in the previous step).
You should see generated proxy class name and namespace.
In my case, the namespace is SoapClient.CalculatorServiceReference
, the name of proxy class is CalculatorSoapClient
. As I said above, class names may vary in your case.
Go to your C# source code and add the following
using WindowsFormsApplication1.ServiceReference1
Now you can call the service this way.
Service1Client service = new Service1Client();
int year = service.getCurrentYear();
Hope this helps. If you encounter any problems, let us know.
JS jQuery - check if value is in array
The Array.prototype
property represents the prototype for the Array
constructor and allows you to add new properties
and methods
to all Array
objects. we can create a prototype for this purpose
Array.prototype.has_element = function(element) {
return $.inArray( element, this) !== -1;
};
And then use it like this
var numbers= [1, 2, 3, 4];
numbers.has_element(3) => true
numbers.has_element(10) => false
See the Demo below
_x000D_
_x000D_
Array.prototype.has_element = function(element) {_x000D_
return $.inArray(element, this) !== -1;_x000D_
};_x000D_
_x000D_
_x000D_
_x000D_
var numbers = [1, 2, 3, 4];_x000D_
console.log(numbers.has_element(3));_x000D_
console.log(numbers.has_element(10));
_x000D_
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
_x000D_
_x000D_
_x000D_
How to force a hover state with jQuery?
You will have to use a class, but don't worry, it's pretty simple. First we'll assign your :hover
rules to not only apply to physically-hovered links, but also to links that have the classname hovered
.
a:hover, a.hovered { color: #ccff00; }
Next, when you click #btn
, we'll toggle the .hovered
class on the #link
.
$("#btn").click(function() {
$("#link").toggleClass("hovered");
});
If the link has the class already, it will be removed. If it doesn't have the class, it will be added.
How to format an inline code in Confluence?
By default Confluence renders monospaced text with transparent background. You can edit global CSS to add grey color. From Confluence manual:
- Choose the cog icon at top right of the screen, then choose Confluence Admin.
- Choose Stylesheet.
- Choose Edit.
- Paste your custom CSS into the text field.
- Choose Save.
Custom CSS for displaying grey background in monospaced blocks:
code {
padding: 1px 5px 1px 5px;
font-family: Consolas, Menlo, Monaco, Lucida Console, Liberation Mono, DejaVu Sans Mono, Bitstream Vera Sans Mono, Courier New, monospace, serif;
background-color: #eeeeee;
}
If you're using Confluence OnDemand (cloud):
- Click the cog/gear in the bottom of the sidebar on the left
- Select Look and Feel
- Click the Sidebar, Header and Footer tab
- Paste your custom CSS into the Header field
- Wrap the code in a
{style}
block
- Save
Paste the following:
{style}
code {
padding: 1px 5px 1px 5px;
font-family: Consolas, Menlo, Monaco, Lucida Console, Liberation Mono, DejaVu Sans Mono, Bitstream Vera Sans Mono, Courier New, monospace, serif;
background-color: #eeeeee;
}
{style}
After that you'll get nice and tidy stackoverflow-stylish inline code spans just by writing {{sometext}}
.
create a trusted self-signed SSL cert for localhost (for use with Express/Node)
Mkcert from @FiloSottile makes this process infinitely simpler:
- Install mkcert, there are instructions for macOS/Windows/Linux
mkcert -install
to create a local CA
mkcert localhost 127.0.0.1 ::1
to create a trusted cert for localhost in the current directory
- You're using node (which doesn't use the system root store), so you need to specify the CA explicitly in an environment variable, e.g:
export NODE_EXTRA_CA_CERTS="$(mkcert -CAROOT)/rootCA.pem"
- Finally run your express server using the setup described in various other answers (e.g. below)
- boom. localhost's swimming in green.
Basic node setup:
const https = require('https');
const fs = require('fs');
const express = require('express');
const app = express();
const server = https.createServer({
key: fs.readFileSync('/XXX/localhost+2-key.pem'), // where's me key?
cert: fs.readFileSync('/XXX/localhost+2.pem'), // where's me cert?
requestCert: false,
rejectUnauthorized: false,
}, app).listen(10443); // get creative
How to run a C# application at Windows startup?
I think there is a specific Win32 API call which takes the application path and puts it in the registry automatically for you in the proper location, I've used it in the past but I don't remember the function name anymore.
How to remove all white spaces in java
Why not use a regex for this?
a = a.replaceAll("\\s","");
In the context of a regex, \s
will remove anything that is a space character (including space, tab characters etc). You need to escape the backslash in Java so the regex turns into \\s
. Also, since Strings are immutable it is important that you assign the return value of the regex to a
.
How do I encode and decode a base64 string?
URL safe Base64 Encoding/Decoding
public static class Base64Url
{
public static string Encode(string text)
{
return Convert.ToBase64String(Encoding.UTF8.GetBytes(text)).TrimEnd('=').Replace('+', '-')
.Replace('/', '_');
}
public static string Decode(string text)
{
text = text.Replace('_', '/').Replace('-', '+');
switch (text.Length % 4)
{
case 2:
text += "==";
break;
case 3:
text += "=";
break;
}
return Encoding.UTF8.GetString(Convert.FromBase64String(text));
}
}
Git merge is not possible because I have unmerged files
It might be the Unmerged paths that cause
error: Merging is not possible because you have unmerged files.
If so, try:
git status
if it says
You have unmerged paths.
do as suggested: either resolve conflicts and then commit or abort the merge entirely with
git merge --abort
You might also see files listed under Unmerged paths, which you can resolve by doing
git rm <file>
How to trim a string after a specific character in java
Assuming you just want everything before \n
(or any other literal string/char), you should use indexOf()
with substring()
:
result = result.substring(0, result.indexOf('\n'));
If you want to extract the portion before a certain regular expression, you can use split()
:
result = result.split(regex, 2)[0];
String result = "34.1 -118.33\n<!--ABCDEFG-->";
System.out.println(result.substring(0, result.indexOf('\n')));
System.out.println(result.split("\n", 2)[0]);
34.1 -118.33
34.1 -118.33
(Obviously \n
isn't a meaningful regular expression, I just used it to demonstrate that the second approach also works.)
Mac zip compress without __MACOSX folder?
Do you mean the zip
command-line tool or the Finder's Compress command?
For zip
, you can try the --data-fork
option. If that doesn't do it, you might try --no-extra
, although that seems to ignore other file metadata that might be valuable, like uid/gid and file times.
For the Finder's Compress command, I don't believe there are any options to control its behavior. It's for the simple case.
The other tool, and maybe the one that the Finder actually uses under the hood, is ditto
. With the -c -k
options, it creates zip archives. With this tool, you can experiment with --norsrc
, --noextattr
, --noqtn
, --noacl
and/or simply leave off the --sequesterRsrc
option (which, according to the man page, may be responsible for the __MACOSX
subdirectory). Although, perhaps the absence of --sequesterRsrc
simply means to use AppleDouble format, which would create ._ files all over the place instead of one __MACOSX
directory.
Close virtual keyboard on button press
mMyTextView.setOnEditorActionListener(new TextView.OnEditorActionListener() {
public boolean onEditorAction(TextView v, int actionId, KeyEvent event) {
if (actionId == EditorInfo.IME_ACTION_SEARCH) {
// hide virtual keyboard
InputMethodManager imm = (InputMethodManager)getSystemService(Context.INPUT_METHOD_SERVICE);
imm.hideSoftInputFromWindow(m_txtSearchText.getWindowToken(),
InputMethodManager.RESULT_UNCHANGED_SHOWN);
return true;
}
return false;
}
});
Tesseract running error
For Windows Users:
In Environment Variables, add a new variable in system variable with name "TESSDATA_PREFIX" and value is "C:\Program Files (x86)\Tesseract-OCR\tessdata"
jQuery - Follow the cursor with a DIV
This works for me. Has a nice delayed action going on.
var $mouseX = 0, $mouseY = 0;
var $xp = 0, $yp =0;
$(document).mousemove(function(e){
$mouseX = e.pageX;
$mouseY = e.pageY;
});
var $loop = setInterval(function(){
// change 12 to alter damping higher is slower
$xp += (($mouseX - $xp)/12);
$yp += (($mouseY - $yp)/12);
$("#moving_div").css({left:$xp +'px', top:$yp +'px'});
}, 30);
Nice and simples
Change :hover CSS properties with JavaScript
Had some same problems, used addEventListener for events "mousenter", "mouseleave":
let DOMelement = document.querySelector('CSS selector for your HTML element');
// if you want to change e.g color:
let origColorStyle = DOMelement.style.color;
DOMelement.addEventListener("mouseenter", (event) => { event.target.style.color = "red" });
DOMelement.addEventListener("mouseleave", (event) => { event.target.style.color = origColorStyle })
Or something else for style when cursor is above the DOMelement.
DOMElement can be chosen by various ways.
String Resource new line /n not possible?
When using the translations editor in Android Studio just click the icon to the right (or use Shift-Enter on Windows, Alt/Option-Enter on MacOS) and then add line breaks using return.
This will insert \n
correctly in the localized strings.xml.
How do you split and unsplit a window/view in Eclipse IDE?
This is possible with the menu items Window>Editor>Toggle Split Editor.
Current shortcut for splitting is:
Azerty keyboard:
- Ctrl + _ for split horizontally, and
- Ctrl + { for split vertically.
Qwerty US keyboard:
- Ctrl + Shift + - (accessing _) for split horizontally, and
- Ctrl + Shift + [ (accessing {) for split vertically.
MacOS - Qwerty US keyboard:
- ⌘ + Shift + - (accessing _) for split horizontally, and
- ⌘ + Shift + [ (accessing {) for split vertically.
On any other keyboard if a required key is unavailable (like { on a german Qwertz keyboard), the following generic approach may work:
- Alt + ASCII code + Ctrl then release Alt
Example: ASCII for '{' = 123, so press 'Alt', '1', '2', '3', 'Ctrl' and release 'Alt', effectively typing '{' while 'Ctrl' is pressed, to split vertically.
Example of vertical split:
PS:
- The menu items Window>Editor>Toggle Split Editor were added with Eclipse Luna 4.4 M4, as mentioned by Lars Vogel in "Split editor implemented in Eclipse M4 Luna"
- The split editor is one of the oldest and most upvoted Eclipse bug! Bug 8009
- The split editor functionality has been developed in Bug 378298, and will be available as of Eclipse Luna M4. The Note & Newsworthy of Eclipse Luna M4 will contain the announcement.
Should I set max pool size in database connection string? What happens if I don't?
Currently your application support 100 connections in pool. Here is what conn string will look like if you want to increase it to 200:
public static string srConnectionString =
"server=localhost;database=mydb;uid=sa;pwd=mypw;Max Pool Size=200;";
You can investigate how many connections with database your application use, by executing sp_who
procedure in your database. In most cases default connection pool size will be enough.
Find the unique values in a column and then sort them
Came across the question myself today. I think the reason that your code returns 'None' (exactly what I got by using the same method) is that
a.sort()
is calling the sort function to mutate the list a. In my understanding, this is a modification command. To see the result you have to use print(a).
My solution, as I tried to keep everything in pandas:
pd.Series(df['A'].unique()).sort_values()
Ruby optional parameters
It isn't possible to do it the way you've defined ldap_get
. However, if you define ldap_get
like this:
def ldap_get ( base_dn, filter, attrs=nil, scope=LDAP::LDAP_SCOPE_SUBTREE )
Now you can:
ldap_get( base_dn, filter, X )
But now you have problem that you can't call it with the first two args and the last arg (the same problem as before but now the last arg is different).
The rationale for this is simple: Every argument in Ruby isn't required to have a default value, so you can't call it the way you've specified. In your case, for example, the first two arguments don't have default values.
How to get the difference between two dictionaries in Python?
What about this? Not as pretty but explicit.
orig_dict = {'a' : 1, 'b' : 2}
new_dict = {'a' : 2, 'v' : 'hello', 'b' : 2}
updates = {}
for k2, v2 in new_dict.items():
if k2 in orig_dict:
if v2 != orig_dict[k2]:
updates.update({k2 : v2})
else:
updates.update({k2 : v2})
#test it
#value of 'a' was changed
#'v' is a completely new entry
assert all(k in updates for k in ['a', 'v'])
Java NIO FileChannel versus FileOutputstream performance / usefulness
My experience with larger files sizes has been that java.nio
is faster than java.io
. Solidly faster. Like in the >250% range. That said, I am eliminating obvious bottlenecks, which I suggest your micro-benchmark might suffer from. Potential areas for investigating:
The buffer size. The algorithm you basically have is
- copy from disk to buffer
- copy from buffer to disk
My own experience has been that this buffer size is ripe for tuning. I've settled on 4KB for one part of my application, 256KB for another. I suspect your code is suffering with such a large buffer. Run some benchmarks with buffers of 1KB, 2KB, 4KB, 8KB, 16KB, 32KB and 64KB to prove it to yourself.
Don't perform java benchmarks that read and write to the same disk.
If you do, then you are really benchmarking the disk, and not Java. I would also suggest that if your CPU is not busy, then you are probably experiencing some other bottleneck.
Don't use a buffer if you don't need to.
Why copy to memory if your target is another disk or a NIC? With larger files, the latency incured is non-trivial.
Like other have said, use FileChannel.transferTo()
or FileChannel.transferFrom()
. The key advantage here is that the JVM uses the OS's access to DMA (Direct Memory Access), if present. (This is implementation dependent, but modern Sun and IBM versions on general purpose CPUs are good to go.) What happens is the data goes straight to/from disc, to the bus, and then to the destination... bypassing any circuit through RAM or the CPU.
The web app I spent my days and night working on is very IO heavy. I've done micro benchmarks and real-world benchmarks too. And the results are up on my blog, have a look-see:
Use production data and environments
Micro-benchmarks are prone to distortion. If you can, make the effort to gather data from exactly what you plan to do, with the load you expect, on the hardware you expect.
My benchmarks are solid and reliable because they took place on a production system, a beefy system, a system under load, gathered in logs. Not my notebook's 7200 RPM 2.5" SATA drive while I watched intensely as the JVM work my hard disc.
What are you running on? It matters.
Why not use Double or Float to represent currency?
Most answers have highlighted the reasons why one should not use doubles for money and currency calculations. And I totally agree with them.
It doesn't mean though that doubles can never be used for that purpose.
I have worked on a number of projects with very low gc requirements, and having BigDecimal objects was a big contributor to that overhead.
It's the lack of understanding about double representation and lack of experience in handling the accuracy and precision that brings about this wise suggestion.
You can make it work if you are able to handle the precision and accuracy requirements of your project, which has to be done based on what range of double values is one dealing with.
You can refer to guava's FuzzyCompare method to get more idea. The parameter tolerance is the key.
We dealt with this problem for a securities trading application and we did an exhaustive research on what tolerances to use for different numerical values in different ranges.
Also, there might be situations when you're tempted to use Double wrappers as a map key with hash map being the implementation. It is very risky because Double.equals and hash code for example values "0.5" & "0.6 - 0.1" will cause a big mess.
Align image to left of text on same line - Twitter Bootstrap3
For Bootstrap 3.
<div class="paragraphs">
<div class="row">
<div class="col-md-4">
<div class="content-heading clearfix media">
<h3>Experience   </h3>
<img class="pull-left" src="../site/img/success32.png"/>
</div>
<p>Donec id elit non mi porta gravida at eget metus. Etiam porta sem malesuada magna mollis euismod. Donec sed odio dui.</p>
</div>
</div>
</div>
What does mysql error 1025 (HY000): Error on rename of './foo' (errorno: 150) mean?
You usually get this error if your tables use the InnoDB engine. In that case you would have to drop the foreign key, and then do the alter table and drop the column.
But the tricky part is that you can't drop the foreign key using the column name, but instead you would have to find the name used to index it. To find that, issue the following select:
SHOW CREATE TABLE region;
This should show you the name of the index, something like this:
CONSTRAINT region_ibfk_1
FOREIGN
KEY (country_id
) REFERENCES
country
(id
) ON DELETE NO
ACTION ON UPDATE NO ACTION
Now simply issue an:
alter table region drop foreign key
region_ibfk_1
;
And finally an:
alter table region drop column
country_id;
And you are good to go!
How do I parse a string with a decimal point to a double?
Instead of having to specify a locale in all parses, I prefer to set an application wide locale, although if string formats are not consistent across the app, this might not work.
CultureInfo.DefaultThreadCurrentCulture = new CultureInfo("pt-PT");
CultureInfo.DefaultThreadCurrentUICulture = new CultureInfo("pt-PT");
Defining this at the begining of your application will make all double parses expect a comma as the decimal delimiter. You can set an appropriate locale so that the decimal and thousands separator fits the strings you are parsing.
Get characters after last / in url
Very simply:
$id = substr($url, strrpos($url, '/') + 1);
strrpos gets the position of the last occurrence of the slash; substr returns everything after that position.
As mentioned by redanimalwar if there is no slash this doesn't work correctly since strrpos
returns false. Here's a more robust version:
$pos = strrpos($url, '/');
$id = $pos === false ? $url : substr($url, $pos + 1);