What is the purpose of flush() in Java streams?
Streams are often accessed by threads that periodically empty their content and, for example, display it on the screen, send it to a socket or write it to a file. This is done for performance reasons. Flushing an output stream means that you want to stop, wait for the content of the stream to be completely transferred to its destination, and then resume execution with the stream empty and the content sent.
sql query with multiple where statements
What is meta_key
? Strip out all of the meta_value
conditionals, reduce, and you end up with this:
SELECT
*
FROM
meta_data
WHERE
(
(meta_key = 'lat')
)
AND
(
(meta_key = 'long')
)
GROUP BY
item_id
Since meta_key
can never simultaneously equal two different values, no results will be returned.
Based on comments throughout this question and answers so far, it sounds like you're looking for something more along the lines of this:
SELECT
*
FROM
meta_data
WHERE
(
(meta_key = 'lat')
AND
(
(meta_value >= '60.23457047672217')
OR
(meta_value <= '60.23457047672217')
)
)
OR
(
(meta_key = 'long')
AND
(
(meta_value >= '24.879140853881836')
OR
(meta_value <= '24.879140853881836')
)
)
GROUP BY
item_id
Note the OR
between the top-level conditionals. This is because you want records which are lat
or long
, since no single record will ever be lat
and long
.
I'm still not sure what you're trying to accomplish by the inner conditionals. Any non-null value will match those numbers. So maybe you can elaborate on what you're trying to do there. I'm also not sure about the purpose of the GROUP BY
clause, but that might be outside the context of this question entirely.
Reading binary file and looping over each byte
Reading binary file in Python and looping over each byte
New in Python 3.5 is the pathlib
module, which has a convenience method specifically to read in a file as bytes, allowing us to iterate over the bytes. I consider this a decent (if quick and dirty) answer:
import pathlib
for byte in pathlib.Path(path).read_bytes():
print(byte)
Interesting that this is the only answer to mention pathlib
.
In Python 2, you probably would do this (as Vinay Sajip also suggests):
with open(path, 'b') as file:
for byte in file.read():
print(byte)
In the case that the file may be too large to iterate over in-memory, you would chunk it, idiomatically, using the iter
function with the callable, sentinel
signature - the Python 2 version:
with open(path, 'b') as file:
callable = lambda: file.read(1024)
sentinel = bytes() # or b''
for chunk in iter(callable, sentinel):
for byte in chunk:
print(byte)
(Several other answers mention this, but few offer a sensible read size.)
Best practice for large files or buffered/interactive reading
Let's create a function to do this, including idiomatic uses of the standard library for Python 3.5+:
from pathlib import Path
from functools import partial
from io import DEFAULT_BUFFER_SIZE
def file_byte_iterator(path):
"""given a path, return an iterator over the file
that lazily loads the file
"""
path = Path(path)
with path.open('rb') as file:
reader = partial(file.read1, DEFAULT_BUFFER_SIZE)
file_iterator = iter(reader, bytes())
for chunk in file_iterator:
yield from chunk
Note that we use file.read1
. file.read
blocks until it gets all the bytes requested of it or EOF
. file.read1
allows us to avoid blocking, and it can return more quickly because of this. No other answers mention this as well.
Demonstration of best practice usage:
Let's make a file with a megabyte (actually mebibyte) of pseudorandom data:
import random
import pathlib
path = 'pseudorandom_bytes'
pathobj = pathlib.Path(path)
pathobj.write_bytes(
bytes(random.randint(0, 255) for _ in range(2**20)))
Now let's iterate over it and materialize it in memory:
>>> l = list(file_byte_iterator(path))
>>> len(l)
1048576
We can inspect any part of the data, for example, the last 100 and first 100 bytes:
>>> l[-100:]
[208, 5, 156, 186, 58, 107, 24, 12, 75, 15, 1, 252, 216, 183, 235, 6, 136, 50, 222, 218, 7, 65, 234, 129, 240, 195, 165, 215, 245, 201, 222, 95, 87, 71, 232, 235, 36, 224, 190, 185, 12, 40, 131, 54, 79, 93, 210, 6, 154, 184, 82, 222, 80, 141, 117, 110, 254, 82, 29, 166, 91, 42, 232, 72, 231, 235, 33, 180, 238, 29, 61, 250, 38, 86, 120, 38, 49, 141, 17, 190, 191, 107, 95, 223, 222, 162, 116, 153, 232, 85, 100, 97, 41, 61, 219, 233, 237, 55, 246, 181]
>>> l[:100]
[28, 172, 79, 126, 36, 99, 103, 191, 146, 225, 24, 48, 113, 187, 48, 185, 31, 142, 216, 187, 27, 146, 215, 61, 111, 218, 171, 4, 160, 250, 110, 51, 128, 106, 3, 10, 116, 123, 128, 31, 73, 152, 58, 49, 184, 223, 17, 176, 166, 195, 6, 35, 206, 206, 39, 231, 89, 249, 21, 112, 168, 4, 88, 169, 215, 132, 255, 168, 129, 127, 60, 252, 244, 160, 80, 155, 246, 147, 234, 227, 157, 137, 101, 84, 115, 103, 77, 44, 84, 134, 140, 77, 224, 176, 242, 254, 171, 115, 193, 29]
Don't iterate by lines for binary files
Don't do the following - this pulls a chunk of arbitrary size until it gets to a newline character - too slow when the chunks are too small, and possibly too large as well:
with open(path, 'rb') as file:
for chunk in file: # text newline iteration - not for bytes
yield from chunk
The above is only good for what are semantically human readable text files (like plain text, code, markup, markdown etc... essentially anything ascii, utf, latin, etc... encoded) that you should open without the 'b'
flag.
How do I use modulus for float/double?
I thought the regular modulus operator would work for this in java, but it can't be hard to code. Just divide the numerator by the denominator, and take the integer portion of the result. Multiply that by the denominator, and subtract the result from the numerator.
x = n / d
xint = Integer portion of x
result = n - d * xint
How can I nullify css property?
You need to provide a selector with higher specificity than the one in Main.css
. With that selector, set the values of the properties you want to their default, e.g.
body .c1 {
height: auto;
}
There is no "default" value that will work for all properties, you need to look up what the default is for each one and use that.
TypeError: 'int' object is not subscriptable
Just to be clear, all the answers so far are correct, but the reasoning behind them is not explained very well.
The sumall
variable is not yet a string. Parentheticals will not convert to a string (e.g. summ = (int(birthday[0])+int(birthday[1]))
still returns an integer. It looks like you most likely intended to type str((int(sumall[0])+int(sumall[1])))
, but forgot to. The reason the str()
function fixes everything is because it converts anything in it compatible to a string.
Storing database records into array
$memberId =$_SESSION['TWILLO']['Id'];
$QueryServer=mysql_query("select * from smtp_server where memberId='".$memberId."'");
$data = array();
while($ser=mysql_fetch_assoc($QueryServer))
{
$data[$ser['Id']] =array('ServerName','ServerPort','Server_limit','email','password','status');
}
Convert time fields to strings in Excel
Copy to a Date variable then transform it into Text with format()
. Example:
Function GetMyTimeField()
Dim myTime As Date, myStrTime As String
myTime = [A1]
myStrTime = Format(myTime, "hh:mm")
Debug.Print myStrTime & " Nice!"
End Function
Running Selenium Webdriver with a proxy in Python
try running tor service, add the following function to your code.
def connect_tor(port):
socks.set_default_proxy(socks.PROXY_TYPE_SOCKS5, '127.0.0.1', port, True)
socket.socket = socks.socksocket
def main():
connect_tor()
driver = webdriver.Firefox()
Switch case with conditions
Switch case is every help full instead of if else statement :
switch ($("[id*=btnSave]").val()) {
case 'Search':
saveFlight();
break;
case 'Update':
break;
case 'Delete':
break;
default:
break;
}
Difference between break and continue in PHP?
I am not writing anything same here. Just a changelog note from PHP manual.
Changelog for continue
Version Description
7.0.0 - continue outside of a loop or switch control structure is now detected at compile-time instead of run-time as before, and triggers an E_COMPILE_ERROR.
5.4.0 continue 0; is no longer valid. In previous versions it was interpreted the same as continue 1;.
5.4.0 Removed the ability to pass in variables (e.g., $num = 2; continue $num;) as the numerical argument.
Changelog for break
Version Description
7.0.0 break outside of a loop or switch control structure is now detected at compile-time instead of run-time as before, and triggers an E_COMPILE_ERROR.
5.4.0 break 0; is no longer valid. In previous versions it was interpreted the same as break 1;.
5.4.0 Removed the ability to pass in variables (e.g., $num = 2; break $num;) as the numerical argument.
while EOF in JAVA?
The others told you enough about your issue with multiple calls of readLine()
.
I just wanted to leave sth about code style:
While you see this line =
assignement and != null
check together in one while condition in most examples (like @gotomanners example here) I prefer using a for
for it.
It is much more readable in my opinion ...
for (String line = in.readLine(); line != null; line = in.readLine()) {
...
}
Another nice way to write it you see in @TheCapn's example. But when you write it that way you easily see that's what a for-loop is made for.
I do not like assignments scrambled with conditions in one line. It is bad style in my opinion. But because it is so MUCH popular for that special case here to do it that way I would not consider it really bad style. (But cannot understand who established this bad style to become that popular.)
Datanode process not running in Hadoop
Follow these steps and your datanode will start again.
1)Stop dfs.
2)Open hdfs-site.xml
3)Remove the data.dir and name.dir properties from hdfs-site.xml and -format namenode again.
4)Then start dfs again.
How to update only one field using Entity Framework?
public void ChangePassword(int userId, string password)
{
var user = new User{ Id = userId, Password = password };
using (var db = new DbContextName())
{
db.Entry(user).State = EntityState.Added;
db.SaveChanges();
}
}
How to stretch a fixed number of horizontal navigation items evenly and fully across a specified container
This one really works. Also has the benefit that you can use media queries to easily turn off the horizontal style — for instance if you want to stack them vertically when on mobile phone.
HTML
<ul id="nav">
<li><a href="#">Link</a></li>
<li><a href="#">Link</a></li>
<li><a href="#">Link</a></li>
<li><a href="#">Link</a></li>
<li><a href="#">Link</a></li>
<li><a href="#">Link</a></li>
</ul>
CSS
?
#nav {
display: table;
height: 87px;
width: 100%;
}
#nav li {
display: table-cell;
height: 87px;
width: 16.666666667%; /* (100 / numItems)% */
line-height: 87px;
text-align: center;
background: #ddd;
border-right: 1px solid #fff;
white-space: nowrap;
}?
@media (max-width: 767px) {
#nav li {
display: block;
width: 100%;
}
}
http://jsfiddle.net/timshutes/eCPSh/416/
How to fix warning from date() in PHP"
You could also use this:
ini_alter('date.timezone','Asia/Calcutta');
You should call this before calling any date function. It accepts the key as the first parameter to alter PHP settings during runtime and the second parameter is the value.
I had done these things before I figured out this:
- Changed the PHP.timezone to "Asia/Calcutta" - but did not work
- Changed the lat and long parameters in the ini - did not work
- Used
date_default_timezone_set("Asia/Calcutta");
- did not work
- Used
ini_alter()
- IT WORKED
- Commented
date_default_timezone_set("Asia/Calcutta");
- IT WORKED
- Reverted the changes made to the PHP.ini - IT WORKED
For me the init_alter()
method got it all working.
I am running Apache 2 (pre-installed), PHP 5.3 on OSX mountain lion
How to merge a specific commit in Git
The leading answers describe how to apply the changes from a specific commit to the current branch. If that's what you mean by "how to merge," then just use cherry-pick as they suggest.
But if you actually want a merge, i.e. you want a new commit with two parents -- the existing commit on the current branch, and the commit you wanted to apply changes from -- then a cherry-pick will not accomplish that.
Having true merge history may be desirable, for example, if your build process takes advantage of git ancestry to automatically set version strings based on the latest tag (using git describe
).
Instead of cherry-pick, you can do an actual git merge --no-commit
, and then manually adjust the index to remove any changes you don't want.
Suppose you're on branch A
and you want to merge the commit at the tip of branch B
:
git checkout A
git merge --no-commit B
Now you're set up to create a commit with two parents, the current tip commits of A
and B
. However you may have more changes applied than you want, including changes from earlier commits on the B branch. You need to undo these unwanted changes, then commit.
(There may be an easy way to set the state of the working directory and the index back to way it was before the merge, so that you have a clean slate onto which to cherry-pick the commit you wanted in the first place. But I don't know how to achieve that clean slate. git checkout HEAD
and git reset HEAD
will both remove the merge state, defeating the purpose of this method.)
So manually undo the unwanted changes. For example, you could
git revert --no-commit 012ea56
for each unwanted commit 012ea56
.
When you're finished adjusting things, create your commit:
git commit -m "Merge in commit 823749a from B which tweaked the timeout code"
Now you have only the change you wanted, and the ancestry tree shows that you technically merged from B.
Adding a newline into a string in C#
The previous answers come close, but to meet the actual requirement that the @
symbol stay close, you'd want that to be str.Replace("@", "@" + System.Environment.NewLine)
. That will keep the @
symbol and add the appropriate newline character(s) for the current platform.
No module named Image
You are missing PIL (Python Image Library and Imaging package). To install PIL I used
pip install pillow
For my machine running Mac OSX 10.6.8, I downloaded Imaging package and installed it from source.
http://effbot.org/downloads/Imaging-1.1.6.tar.gz and cd into Download directory. Then run these:
$ gunzip Imaging-1.1.6.tar.gz
$ tar xvf Imaging-1.1.6.tar
$ cd Imaging-1.1.6
$ python setup.py install
Or if you have PIP installed in your Mac
pip install http://effbot.org/downloads/Imaging-1.1.6.tar.gz
then you can use:
from PIL import Image
in your python code.
What are the most common naming conventions in C?
I think those can help for beginner:
Naming convention of variables in c
- You have to use Alphabetic Character (a-z, A-Z), Digit (0-9) and Under Score (_). It’s not allow to use any special Character like: %, $, #, @ etc. So, you can use user_name as variable but cannot use user&name.
- Can not use white space between words. So, you can use user_name or username or username as variable but cannot use user name.
- Can not start naming with digit. So, you can use user1 or user2 as variable but cannot use 1user.
- It is case sensitive language. Uppercase and lowercase are significant. If you use a variable like username then you cannot use USERNAME or Username for father use.
- You can not use any keyword (char, int, if, for, while etc) for variable declaration.
- ANSI standard recognizes a length of 31 characters for a variable name
Drop rows containing empty cells from a pandas DataFrame
Pythonic + Pandorable: df[df['col'].astype(bool)]
Empty strings are falsy, which means you can filter on bool values like this:
df = pd.DataFrame({
'A': range(5),
'B': ['foo', '', 'bar', '', 'xyz']
})
df
A B
0 0 foo
1 1
2 2 bar
3 3
4 4 xyz
df['B'].astype(bool)
0 True
1 False
2 True
3 False
4 True
Name: B, dtype: bool
df[df['B'].astype(bool)]
A B
0 0 foo
2 2 bar
4 4 xyz
If your goal is to remove not only empty strings, but also strings only containing whitespace, use str.strip
beforehand:
df[df['B'].str.strip().astype(bool)]
A B
0 0 foo
2 2 bar
4 4 xyz
Faster than you Think
.astype
is a vectorised operation, this is faster than every option presented thus far. At least, from my tests. YMMV.
Here is a timing comparison, I've thrown in some other methods I could think of.
Benchmarking code, for reference:
import pandas as pd
import perfplot
df1 = pd.DataFrame({
'A': range(5),
'B': ['foo', '', 'bar', '', 'xyz']
})
perfplot.show(
setup=lambda n: pd.concat([df1] * n, ignore_index=True),
kernels=[
lambda df: df[df['B'].astype(bool)],
lambda df: df[df['B'] != ''],
lambda df: df[df['B'].replace('', np.nan).notna()], # optimized 1-col
lambda df: df.replace({'B': {'': np.nan}}).dropna(subset=['B']),
],
labels=['astype', "!= ''", "replace + notna", "replace + dropna", ],
n_range=[2**k for k in range(1, 15)],
xlabel='N',
logx=True,
logy=True,
equality_check=pd.DataFrame.equals)
dynamically set iframe src
You should also consider that in some Opera versions onload is fired several times and add some hooks:
// fixing Opera 9.26, 10.00
if (doc.readyState && doc.readyState != 'complete') {
// Opera fires load event multiple times
// Even when the DOM is not ready yet
// this fix should not affect other browsers
return;
}
// fixing Opera 9.64
if (doc.body && doc.body.innerHTML == "false") {
// In Opera 9.64 event was fired second time
// when body.innerHTML changed from false
// to server response approx. after 1 sec
return;
}
Code borrowed from Ajax Upload
Cannot find runtime 'node' on PATH - Visual Studio Code and Node.js
I also encountered this issue. Did the following and it got fixed.
- Open your computer terminal (not VSCode terminal) and type node --version to ensure you have node installed. If not, then install node using nvm.
- Then head to your bash file (eg .bashrc, .bash_profile, .profile) and add the PATH:
[ -s "$NVM_DIR/nvm.sh" ] && \. "$NVM_DIR/nvm.sh" # This loads nvm
[ -s "$NVM_DIR/bash_completion" ] && \. "$NVM_DIR/bash_completion"
- If you have multiple bash files, you ensure to add the PATH to all of them.
- Restart your VSCode terminal and it should be fine.
Is it .yaml or .yml?
After reading a bunch of people's comments online about this, my first reaction was that this is basically one of those really unimportant debates. However, my initial interest was to find out the right format so I could be consistent with my file naming practice.
Long story short, the creator of YAML are saying .yaml
, but personally I keep doing .yml
. That just makes more sense to me. So I went on the journey to find affirmation and soon enough, I realise that docker uses .yml
everywhere. I've been writing docker-compose.yml
files all this time, while you keep seeing in kubernetes' docs kubectl apply -f *.yaml
...
So, in conclusion, both formats are obviously accepted and if you are on the other end, (ie: writing systems that receive a YAML file as input) you should allow for both. That seems like another snake case versus camel case thingy...
How to define two fields "unique" as couple
Django 2.2+
Using the constraints
features UniqueConstraint
is preferred over unique_together.
From the Django documentation for unique_together
:
Use UniqueConstraint with the constraints option instead.
UniqueConstraint provides more functionality than unique_together.
unique_together may be deprecated in the future.
For example:
class Volume(models.Model):
id = models.AutoField(primary_key=True)
journal_id = models.ForeignKey(Journals, db_column='jid', null=True, verbose_name="Journal")
volume_number = models.CharField('Volume Number', max_length=100)
comments = models.TextField('Comments', max_length=4000, blank=True)
class Meta:
constraints = [
models.UniqueConstraint(fields=['journal_id', 'volume_number'], name='name of constraint')
]
callback to handle completion of pipe
Streams are EventEmitter
s so you can listen to certain events. As you said there is a finish
event for request (previously end
).
var stream = request(...).pipe(...);
stream.on('finish', function () { ... });
For more information about which events are available you can check the stream documentation page.
Use JavaScript to place cursor at end of text in text input element
After hacking around with this a bit, I found the best way was to use the setSelectionRange
function if the browser supports it; if not, revert to using the method in Mike Berrow's answer (i.e. replace the value with itself).
I'm also setting scrollTop
to a high value in case we're in a vertically-scrollable textarea
. (Using an arbitrary high value seems more reliable than $(this).height()
in Firefox and Chrome.)
I've made it is as a jQuery plugin. (If you're not using jQuery I trust you can still get the gist easily enough.)
I've tested in IE6, IE7, IE8, Firefox 3.5.5, Google Chrome 3.0, Safari 4.0.4, Opera 10.00.
It's available on jquery.com as the PutCursorAtEnd plugin. For your convenience, the code for release 1.0 is as follows:
// jQuery plugin: PutCursorAtEnd 1.0
// http://plugins.jquery.com/project/PutCursorAtEnd
// by teedyay
//
// Puts the cursor at the end of a textbox/ textarea
// codesnippet: 691e18b1-f4f9-41b4-8fe8-bc8ee51b48d4
(function($)
{
jQuery.fn.putCursorAtEnd = function()
{
return this.each(function()
{
$(this).focus()
// If this function exists...
if (this.setSelectionRange)
{
// ... then use it
// (Doesn't work in IE)
// Double the length because Opera is inconsistent about whether a carriage return is one character or two. Sigh.
var len = $(this).val().length * 2;
this.setSelectionRange(len, len);
}
else
{
// ... otherwise replace the contents with itself
// (Doesn't work in Google Chrome)
$(this).val($(this).val());
}
// Scroll to the bottom, in case we're in a tall textarea
// (Necessary for Firefox and Google Chrome)
this.scrollTop = 999999;
});
};
})(jQuery);
How to implement a material design circular progress bar in android
With the Material Components library you can use the CircularProgressIndicator
:
Something like:
<com.google.android.material.progressindicator.CircularProgressIndicator
android:indeterminate="true"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
app:indicatorColor="@array/progress_colors"
app:indicatorSize="xxdp"
app:showAnimationBehavior="inward"/>
where array/progress_colors
is an array with the colors:
<integer-array name="progress_colors">
<item>@color/yellow_500</item>
<item>@color/blue_700</item>
<item>@color/red_500</item>
</integer-array>
Note: it requires at least the version 1.3.0
ios Upload Image and Text using HTTP POST
here's the working swift code translated from the code provided by @xjones.
Thanks alot for your help mate. Yours was the only way that worked for me.
I used this method to send 1 image and a another parameter to a webservice made in asp.net
let params = NSMutableDictionary()
let boundaryConstant = "----------V2y2HFg03eptjbaKO0j1"
let file1ParamConstant = "file1"
params.setObject(device_id!, forKey: "deviceID")
let requestUrl = NSURL(string: "\(siteurl):\(port)/FileUpload/Upload")
let request = NSMutableURLRequest()
request.cachePolicy = NSURLRequestCachePolicy.ReloadIgnoringLocalCacheData
request.HTTPShouldHandleCookies=false
request.timeoutInterval = 30
request.HTTPMethod = "POST"
let contentType = "multipart/form-data; boundary=\(boundaryConstant)"
request.setValue(contentType, forHTTPHeaderField: "Content-Type")
let body = NSMutableData()
// parameters
for param in params {
body.appendData("--\(boundaryConstant)\r\n" .dataUsingEncoding(NSUTF8StringEncoding)! )
body.appendData("Content-Disposition: form-data; name=\"\(param)\"\r\n\r\n" .dataUsingEncoding(NSUTF8StringEncoding)!)
body.appendData("\(param.value)\r\n" .dataUsingEncoding(NSUTF8StringEncoding)!)
}
// images
// image begin
body.appendData("--\(boundaryConstant)\r\n".dataUsingEncoding(NSUTF8StringEncoding)!)
body.appendData("Content-Disposition: form-data; name=\"\(file1ParamConstant)\"; filename=\"image.jpg\"\r\n".dataUsingEncoding(NSUTF8StringEncoding)!)
body.appendData("Content-Type: image/jpeg\r\n\r\n".dataUsingEncoding(NSUTF8StringEncoding)!)
body.appendData(passportImageData)
body.appendData("\r\n".dataUsingEncoding(NSUTF8StringEncoding)!)
// image end
body.appendData("--\(boundaryConstant)--\r\n".dataUsingEncoding(NSUTF8StringEncoding)!)
request.HTTPBody = body
let postLength = "\(body.length)"
request.setValue(postLength, forHTTPHeaderField: "Content-Length")
request.URL = requestUrl
var serverResponse = NSString()
let task = NSURLSession.sharedSession().dataTaskWithRequest(request) {
data, response, error in
if error != nil
{
print("error=\(error)")
return
}
print("response = \(response)")
let responseString = NSString(data: data!, encoding: NSUTF8StringEncoding)
print("responseString = \(responseString!)")
serverResponse = responseString!
}
task.resume()
Is there a way to set background-image as a base64 encoded image?
I tried this (and worked for me):
var img = 'data:image/png;base64, ...'; //place ur base64 encoded img here
document.body.style.backgroundImage = 'url(\'' + img + '\')';
ES6 syntax:
let img = 'data:image/png;base64, ...'
document.body.style.backgroundImage = `url('${img}')`
A bit better:
let setBackground = src => {
this.style.backgroundImage = `url('${src}')`
};
let node = nodeIGotFromDOM, img = imageBase64EncodedFromMyGF;
setBackground.call(node, img);
Unsupported method: BaseConfig.getApplicationIdSuffix()
You can do this by changing the gradle file.
build.gradle > change
dependencies {
classpath 'com.android.tools.build:gradle:3.0.1'
}
gradle-wrapper.properties > update
distributionUrl=https://services.gradle.org/distributions/gradle-4.6-all.zip
How do you create a toggle button?
If you want a proper button then you'll need some javascript. Something like this (needs some work on the styling but you get the gist). Wouldn't bother using jquery for something so trivial to be honest.
<html>
<head>
<style type="text/css">
.on {
border:1px outset;
color:#369;
background:#efefef;
}
.off {
border:1px outset;
color:#369;
background:#f9d543;
}
</style>
<script language="javascript">
function togglestyle(el){
if(el.className == "on") {
el.className="off";
} else {
el.className="on";
}
}
</script>
</head>
<body>
<input type="button" id="btn" value="button" class="off" onclick="togglestyle(this)" />
</body>
</html>
What is the difference between a process and a thread?
The best answer I've found so far is Michael Kerrisk's 'The Linux Programming Interface':
In modern UNIX implementations, each process can have multiple threads
of execution. One way of envisaging threads is as a set of processes
that share the same virtual memory, as well as a range of other
attributes. Each thread is executing the same program code and shares
the same data area and heap. However, each thread has it own stack
containing local variables and function call linkage information. [LPI 2.12]
This book is a source of great clarity; Julia Evans mentioned its help in clearing up how Linux groups really work in this article.
How can I make SQL case sensitive string comparison on MySQL?
Excellent!
I share with you, code from a function that compares passwords:
SET pSignal =
(SELECT DECODE(r.usignal,'YOURSTRINGKEY') FROM rsw_uds r WHERE r.uname =
in_usdname AND r.uvige = 1);
SET pSuccess =(SELECT in_usdsignal LIKE BINARY pSignal);
IF pSuccess = 1 THEN
/*Your code if match*/
ELSE
/*Your code if don't match*/
END IF;
How to append a jQuery variable value inside the .html tag
See this Link
HTML
<div id="products"></div>
JS
var someone = {
"name":"Mahmoude Elghandour",
"price":"174 SR",
"desc":"WE Will BE WITH YOU"
};
var name = $("<div/>",{"text":someone.name,"class":"name"
});
var price = $("<div/>",{"text":someone.price,"class":"price"});
var desc = $("<div />", {
"text": someone.desc,
"class": "desc"
});
$("#products").fadeIn(1500);
$("#products").append(name).append(price).append(desc);
Visual studio code CSS indentation and formatting
To format the code in Visual Studio when you want, press:
(Ctrl + K) & (Ctrl + F)
The auto formatting rules can be found and changed in:
Tools/Options --> (Left sidebar): Text Editor / CSS (or whatever other language you want to change)
For the CSS language the options are unfortunately very limited.
You can also make some changes in: .../ Text Editor / All Languages
IN vs OR in the SQL WHERE Clause
I assume you want to know the performance difference between the following:
WHERE foo IN ('a', 'b', 'c')
WHERE foo = 'a' OR foo = 'b' OR foo = 'c'
According to the manual for MySQL if the values are constant IN
sorts the list and then uses a binary search. I would imagine that OR
evaluates them one by one in no particular order. So IN
is faster in some circumstances.
The best way to know is to profile both on your database with your specific data to see which is faster.
I tried both on a MySQL with 1000000 rows. When the column is indexed there is no discernable difference in performance - both are nearly instant. When the column is not indexed I got these results:
SELECT COUNT(*) FROM t_inner WHERE val IN (1000, 2000, 3000, 4000, 5000, 6000, 7000, 8000, 9000);
1 row fetched in 0.0032 (1.2679 seconds)
SELECT COUNT(*) FROM t_inner WHERE val = 1000 OR val = 2000 OR val = 3000 OR val = 4000 OR val = 5000 OR val = 6000 OR val = 7000 OR val = 8000 OR val = 9000;
1 row fetched in 0.0026 (1.7385 seconds)
So in this case the method using OR is about 30% slower. Adding more terms makes the difference larger. Results may vary on other databases and on other data.
No found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations:
I just solved this error happening in my tests.
Just make sure your test class has all dependencies in the attributes of the class being tested annotated with @MockBean
so SpringBoot test context can wire your classes correctly.
Only if you are testing controller: you need also class annotations to load the Controller context propertly.
Check it out:
@DisplayName("UserController Adapter Test")
@WebMvcTest(UserController.class)
@AutoConfigureMockMvc(addFilters = false)
@Import(TestConfig.class)
public class UserControllerTest {
@Autowired
private MockMvc mockMvc;
@Autowired
private ObjectMapper objectMapper;
@MockBean
private CreateUserCommand createUserCommand;
@MockBean
private GetUserListQuery getUserListQuery;
@MockBean
private GetUserQuery getUserQuery;
MySQL case sensitive query
MySQL queries are not case-sensitive by default. Following is a simple query that is looking for 'value'. However it will return 'VALUE', 'value', 'VaLuE', etc…
SELECT * FROM `table` WHERE `column` = 'value'
The good news is that if you need to make a case-sensitive query, it is very easy to do using the BINARY
operator, which forces a byte by byte comparison:
SELECT * FROM `table` WHERE BINARY `column` = 'value'
What type of hash does WordPress use?
Start phpMyAdmin and access wp_users from your wordpress instance.
Edit record and select user_pass function to match MD5. Write the string that will be your new password in VALUE.
Click, GO.
Go to your wordpress website and enter your new password.
Back to phpMyAdmin you will see that WP changed the HASH to something like $P$B...
enjoy!
Activity has leaked window that was originally added
The "Activity has leaked window that was originally added...
" error occurs when you try show an alert after the Activity
is effectively finished
.
You have two options AFAIK:
- Rethink the login of your alert: call
dismiss()
on the dialog
before actually exiting your activity.
- Put the
dialog
in a different thread and run it on that thread
(independent of the current activity
).
Create a branch in Git from another branch
To create a branch from another branch in your local directory you can use following command.
git checkout -b <sub-branch> branch
For Example:
- name of the new branch to be created 'XYZ'
- name of the branch ABC under which XYZ has to be created
git checkout -b XYZ ABC
Auto-increment primary key in SQL tables
Right-click on the table in SSMS, 'Design' it, and click on the id column. In the properties, set the identity to be seeded @ e.g. 1 and to have increment of 1 - save and you're done.
How to escape single quotes within single quoted strings
If you really want to use single quotes in the outermost layer, remember that you can glue both kinds of quotation. Example:
alias rxvt='urxvt -fg '"'"'#111111'"'"' -bg '"'"'#111111'"'"
# ^^^^^ ^^^^^ ^^^^^ ^^^^
# 12345 12345 12345 1234
Explanation of how '"'"'
is interpreted as just '
:
'
End first quotation which uses single quotes.
"
Start second quotation, using double-quotes.
'
Quoted character.
"
End second quotation, using double-quotes.
'
Start third quotation, using single quotes.
If you do not place any whitespaces between (1) and (2), or between (4) and (5), the shell will interpret that string as a one long word.
What does 'corrupted double-linked list' mean
This might be caused due to different reasons, some user have mentioned other possibilities and I add my case:
I got this error when using multi-threading (both std::pthread
and std::thread
) and the error occurred because I forgot to lock a variable which multi threads may change at the same time.
this error comes randomly in some runs but not all because ... you know accident between to threads is random.
That variable in my case was a global std::vector
which I tried to push_back()
something into it in a function called by threads.. and then I used a std::mutex
and never got this error again.
may help some
Auto-redirect to another HTML page
If you're using Apache and can use a .htaccess
file you should use the following type of redirect. Add the following to an .htaccess
file in the root of your website.
RewriteEngine On
RewriteRule ^/oldfile_path/file_name\.html$ /oldfile_path/file_name.html [R=301,L]
This has the advantage of being a very fast and immediate redirect. It also depends on your reason for the redirect. This is a more permanent method because it sends the HTTP 301 status code signifying that the file has moved permanently and causes many browsers to cache that request. You can change the code to something else like a 302 for temporary redirects.
Otherwise you can do a simple redirect using an HTML <meta>
tag as suggested by others:
<meta http-equiv="refresh" content="5; url=http://example.com/">
By default the content="5"
makes that redirect after 5 seconds. This will be slower and not all browsers support it. A redirect can also be done in the server language of your choice PHP
, Node.js
, etc.
AngularJS $resource RESTful example
$resource was meant to retrieve data from an endpoint, manipulate it and send it back. You've got some of that in there, but you're not really leveraging it for what it was made to do.
It's fine to have custom methods on your resource, but you don't want to miss out on the cool features it comes with OOTB.
EDIT: I don't think I explained this well enough originally, but $resource
does some funky stuff with returns. Todo.get()
and Todo.query()
both return the resource object, and pass it into the callback for when the get completes. It does some fancy stuff with promises behind the scenes that mean you can call $save()
before the get()
callback actually fires, and it will wait. It's probably best just to deal with your resource inside of a promise then()
or the callback method.
Standard use
var Todo = $resource('/api/1/todo/:id');
//create a todo
var todo1 = new Todo();
todo1.foo = 'bar';
todo1.something = 123;
todo1.$save();
//get and update a todo
var todo2 = Todo.get({id: 123});
todo2.foo += '!';
todo2.$save();
//which is basically the same as...
Todo.get({id: 123}, function(todo) {
todo.foo += '!';
todo.$save();
});
//get a list of todos
Todo.query(function(todos) {
//do something with todos
angular.forEach(todos, function(todo) {
todo.foo += ' something';
todo.$save();
});
});
//delete a todo
Todo.$delete({id: 123});
Likewise, in the case of what you posted in the OP, you could get a resource object and then call any of your custom functions on it (theoretically):
var something = src.GetTodo({id: 123});
something.foo = 'hi there';
something.UpdateTodo();
I'd experiment with the OOTB implementation before I went and invented my own however. And if you find you're not using any of the default features of $resource
, you should probably just be using $http
on it's own.
Update: Angular 1.2 and Promises
As of Angular 1.2, resources support promises. But they didn't change the rest of the behavior.
To leverage promises with $resource
, you need to use the $promise
property on the returned value.
Example using promises
var Todo = $resource('/api/1/todo/:id');
Todo.get({id: 123}).$promise.then(function(todo) {
// success
$scope.todos = todos;
}, function(errResponse) {
// fail
});
Todo.query().$promise.then(function(todos) {
// success
$scope.todos = todos;
}, function(errResponse) {
// fail
});
Just keep in mind that the $promise
property is a property on the same values it was returning above. So you can get weird:
These are equivalent
var todo = Todo.get({id: 123}, function() {
$scope.todo = todo;
});
Todo.get({id: 123}, function(todo) {
$scope.todo = todo;
});
Todo.get({id: 123}).$promise.then(function(todo) {
$scope.todo = todo;
});
var todo = Todo.get({id: 123});
todo.$promise.then(function() {
$scope.todo = todo;
});
What is the Swift equivalent of isEqualToString in Objective-C?
Actually, it feels like swift is trying to promote strings to be treated less like objects and more like values. However this doesn't mean under the hood swift doesn't treat strings as objects, as am sure you all noticed that you can still invoke methods on strings and use their properties.
For example:-
//example of calling method (String to Int conversion)
let intValue = ("12".toInt())
println("This is a intValue now \(intValue)")
//example of using properties (fetching uppercase value of string)
let caUpperValue = "ca".uppercaseString
println("This is the uppercase of ca \(caUpperValue)")
In objectC you could pass the reference to a string object through a variable, on top of calling methods on it, which pretty much establishes the fact that strings are pure objects.
Here is the catch when you try to look at String as objects, in swift you cannot pass a string object by reference through a variable. Swift will always pass a brand new copy of the string. Hence, strings are more commonly known as value types in swift. In fact, two string literals will not be identical (===). They are treated as two different copies.
let curious = ("ca" === "ca")
println("This will be false.. and the answer is..\(curious)")
As you can see we are starting to break aways from the conventional way of thinking of strings as objects and treating them more like values. Hence .isEqualToString which was treated as an identity operator for string objects is no more a valid as you can never get two identical string objects in Swift. You can only compare its value, or in other words check for equality(==).
let NotSoCuriousAnyMore = ("ca" == "ca")
println("This will be true.. and the answer is..\(NotSoCuriousAnyMore)")
This gets more interesting when you look at the mutability of string objects in swift. But thats for another question, another day. Something you should probably look into, cause its really interesting. :) Hope that clears up some confusion. Cheers!
Simulate a button click in Jest
I needed to do a little bit of testing myself of a button component. These tests work for me ;-)
import { shallow } from "enzyme";
import * as React from "react";
import Button from "../button.component";
describe("Button Component Tests", () => {
it("Renders correctly in DOM", () => {
shallow(
<Button text="Test" />
);
});
it("Expects to find button HTML element in the DOM", () => {
const wrapper = shallow(<Button text="test"/>)
expect(wrapper.find('button')).toHaveLength(1);
});
it("Expects to find button HTML element with className test in the DOM", () => {
const wrapper = shallow(<Button className="test" text="test"/>)
expect(wrapper.find('button.test')).toHaveLength(1);
});
it("Expects to run onClick function when button is pressed in the DOM", () => {
const mockCallBackClick = jest.fn();
const wrapper = shallow(<Button onClick={mockCallBackClick} className="test" text="test"/>);
wrapper.find('button').simulate('click');
expect(mockCallBackClick.mock.calls.length).toEqual(1);
});
});
How can I access global variable inside class in Python
I understand using a global variable is sometimes the most convenient thing to do, especially in cases where usage of class makes the easiest thing so much harder (e.g., multiprocessing
). I ran into the same problem with declaring global variables and figured it out with some experiments.
The reason that g_c
was not changed by the run
function within your class is that the referencing to the global name within g_c
was not established precisely within the function. The way Python handles global declaration is in fact quite tricky. The command global g_c
has two effects:
Preconditions the entrance of the key "g_c"
into the dictionary accessible by the built-in function, globals()
. However, the key will not appear in the dictionary until after a value is assigned to it.
(Potentially) alters the way Python looks for the variable g_c
within the current method.
The full understanding of (2) is particularly complex. First of all, it only potentially alters, because if no assignment to the name g_c
occurs within the method, then Python defaults to searching for it among the globals()
. This is actually a fairly common thing, as is the case of referencing within a method modules that are imported all the way at the beginning of the code.
However, if an assignment command occurs anywhere within the method, Python defaults to finding the name g_c
within local variables. This is true even when a referencing occurs before an actual assignment, which will lead to the classic error:
UnboundLocalError: local variable 'g_c' referenced before assignment
Now, if the declaration global g_c
occurs anywhere within the method, even after any referencing or assignment, then Python defaults to finding the name g_c
within global variables. However, if you are feeling experimentative and place the declaration after a reference, you will be rewarded with a warning:
SyntaxWarning: name 'g_c' is used prior to global declaration
If you think about it, the way the global declaration works in Python is clearly woven into and consistent with how Python normally works. It's just when you actually want a global variable to work, the norm becomes annoying.
Here is a code that summarizes what I just said (with a few more observations):
g_c = 0
print ("Initial value of g_c: " + str(g_c))
print("Variable defined outside of method automatically global? "
+ str("g_c" in globals()))
class TestClass():
def direct_print(self):
print("Directly printing g_c without declaration or modification: "
+ str(g_c))
#Without any local reference to the name
#Python defaults to search for the variable in globals()
#This of course happens for all the module names you import
def mod_without_dec(self):
g_c = 1
#A local assignment without declaring reference to global variable
#makes Python default to access local name
print ("After mod_without_dec, local g_c=" + str(g_c))
print ("After mod_without_dec, global g_c=" + str(globals()["g_c"]))
def mod_with_late_dec(self):
g_c = 2
#Even with a late declaration, the global variable is accessed
#However, a syntax warning will be issued
global g_c
print ("After mod_with_late_dec, local g_c=" + str(g_c))
print ("After mod_with_late_dec, global g_c=" + str(globals()["g_c"]))
def mod_without_dec_error(self):
try:
print("This is g_c" + str(g_c))
except:
print("Error occured while accessing g_c")
#If you try to access g_c without declaring it global
#but within the method you also alter it at some point
#then Python will not search for the name in globals()
#!!!!!Even if the assignment command occurs later!!!!!
g_c = 3
def sound_practice(self):
global g_c
#With correct declaration within the method
#The local name g_c becomes an alias for globals()["g_c"]
g_c = 4
print("In sound_practice, the name g_c points to: " + str(g_c))
t = TestClass()
t.direct_print()
t.mod_without_dec()
t.mod_with_late_dec()
t.mod_without_dec_error()
t.sound_practice()
I want to exception handle 'list index out of range.'
For anyone interested in a shorter way:
gotdata = len(dlist)>1 and dlist[1] or 'null'
But for best performance, I suggest using False
instead of 'null'
, then a one line test will suffice:
gotdata = len(dlist)>1 and dlist[1]
How to respond with HTTP 400 error in a Spring MVC @ResponseBody method returning String?
Something like this should work, I'm not sure whether or not there is a simpler way:
@RequestMapping(value = "/matches/{matchId}", produces = "application/json")
@ResponseBody
public String match(@PathVariable String matchId, @RequestBody String body,
HttpServletRequest request, HttpServletResponse response) {
String json = matchService.getMatchJson(matchId);
if (json == null) {
response.setStatus( HttpServletResponse.SC_BAD_REQUEST );
}
return json;
}
How to get current date time in milliseconds in android
The problem is that System. currentTimeMillis();
returns the number of milliseconds from 1970-01-01T00:00:00Z, but new Date()
gives the current local time. Adding the ZONE_OFFSET and DST_OFFSET from the Calendar class gives you the time in UTC.
Calendar rightNow = Calendar.getInstance();
// offset to add since we're not UTC
long offset = rightNow.get(Calendar.ZONE_OFFSET) +
rightNow.get(Calendar.DST_OFFSET);
long sinceMidnight = (rightNow.getTimeInMillis() + offset) %
(24 * 60 * 60 * 1000);
System.out.println(sinceMidnight + " milliseconds since midnight");
Regular expression negative lookahead
Lookarounds can be nested.
So this regex matches "drupal-6.14/" that is not followed by "sites" that is not followed by "/all" or "/default".
Confusing? Using different words, we can say it matches "drupal-6.14/" that is not followed by "sites" unless that is further followed by "/all" or "/default"
Best way to strip punctuation from a string
I like to use a function like this:
def scrub(abc):
while abc[-1] is in list(string.punctuation):
abc=abc[:-1]
while abc[0] is in list(string.punctuation):
abc=abc[1:]
return abc
Empty set literal?
There are few ways to create empty Set in Python :
- Using set() method
This is the built-in method in python that creates Empty set in that variable.
- Using clear() method (creative Engineer Technique LOL)
See this Example:
sets={"Hi","How","are","You","All"}
type(sets) (This Line
Output : set)
sets.clear()
print(sets) (This Line Output : {})
type(sets) (This Line
Output : set)
So, This are 2 ways to create empty Set.
TypeError: unsupported operand type(s) for -: 'list' and 'list'
This question has been answered but I feel I should also mention another potential cause. This is a direct result of coming across the same error message but for different reasons. If your list/s are empty the operation will not be performed. check your code for indents and typos
Python Request Post with param data
params
is for GET-style URL parameters, data
is for POST-style body information. It is perfectly legal to provide both types of information in a request, and your request does so too, but you encoded the URL parameters into the URL already.
Your raw post contains JSON data though. requests
can handle JSON encoding for you, and it'll set the correct Content-Type
header too; all you need to do is pass in the Python object to be encoded as JSON into the json
keyword argument.
You could split out the URL parameters as well:
params = {'sessionKey': '9ebbd0b25760557393a43064a92bae539d962103', 'format': 'xml', 'platformId': 1}
then post your data with:
import requests
url = 'http://192.168.3.45:8080/api/v2/event/log'
data = {"eventType": "AAS_PORTAL_START", "data": {"uid": "hfe3hf45huf33545", "aid": "1", "vid": "1"}}
params = {'sessionKey': '9ebbd0b25760557393a43064a92bae539d962103', 'format': 'xml', 'platformId': 1}
requests.post(url, params=params, json=data)
The json
keyword is new in requests
version 2.4.2; if you still have to use an older version, encode the JSON manually using the json
module and post the encoded result as the data
key; you will have to explicitly set the Content-Type header in that case:
import requests
import json
headers = {'content-type': 'application/json'}
url = 'http://192.168.3.45:8080/api/v2/event/log'
data = {"eventType": "AAS_PORTAL_START", "data": {"uid": "hfe3hf45huf33545", "aid": "1", "vid": "1"}}
params = {'sessionKey': '9ebbd0b25760557393a43064a92bae539d962103', 'format': 'xml', 'platformId': 1}
requests.post(url, params=params, data=json.dumps(data), headers=headers)
Getting Exception(org.apache.poi.openxml4j.exception - no content type [M1.13]) when reading xlsx file using Apache POI?
The error is telling you that POI couldn't find a core part of the OOXML file, in this case the content types part. Your file isn't a valid OOXML file, let alone a valid .xlsx file. It is a valid zip file though, otherwise you'd have got an earlier error
Can Excel really load this file? I'd expect it wouldn't be able to, as the exception is most commonly triggered by giving POI a regular .zip file! I suspect your file isn't valid, hence the exception
.
Update: In Apache POI 3.15 (from beta 1 onwards), there's a more helpful set of Exception messages for the more common causes of this problem. You'll now get more descriptive exceptions in this case, eg ODFNotOfficeXmlFileException and OLE2NotOfficeXmlFileException. This raw form should only ever show up if POI really has no clue what you've given it but knows it's broken or invalid.
What is compiler, linker, loader?
Wikipedia ought to have a good answer, here's my thoughts:
- Compiler: reads something.c source, writes something.o object.
- Linker: joins several *.o files into an executable program.
- Loader: code that loads an executable into memory and starts it running.
Python Matplotlib Y-Axis ticks on Right Side of Plot
For right labels use ax.yaxis.set_label_position("right")
, i.e.:
f = plt.figure()
ax = f.add_subplot(111)
ax.yaxis.tick_right()
ax.yaxis.set_label_position("right")
plt.plot([2,3,4,5])
ax.set_xlabel("$x$ /mm")
ax.set_ylabel("$y$ /mm")
plt.show()
How to access random item in list?
Create an instance of Random
class somewhere. Note that it's pretty important not to create a new instance each time you need a random number. You should reuse the old instance to achieve uniformity in the generated numbers. You can have a static
field somewhere (be careful about thread safety issues):
static Random rnd = new Random();
Ask the Random
instance to give you a random number with the maximum of the number of items in the ArrayList
:
int r = rnd.Next(list.Count);
Display the string:
MessageBox.Show((string)list[r]);
Responsive font size in CSS
Use this equation:
calc(42px + (60 - 42) * (100vw - 768px) / (1440 - 768));
For anything larger or smaller than 1440 and 768, you can either give it a static value, or apply the same approach.
The drawback with vw solution is that you cannot set a scale ratio, say a 5vw at screen resolution 1440 may end up being 60px font-size, your idea font size, but when you shrink the window width down to 768, it may ended up being 12px, not the minimal you want.
With this approach, you can set your upper boundary and lower boundary, and the font will scale itself in between.
FileNotFoundError: [Errno 2] No such file or directory
Lets say we have a script in "c:\script.py" that contain :
result = open("index.html","r")
print(result.read())
Lets say that the index.html file is also in the same directory "c:\index.html"
when i execute the script from cmd (or shell)
C:\Users\Amine>python c:\script.py
You will get error:
FileNotFoundError: [Errno 2] No such file or directory: 'index.html'
And that because "index.html" is not in working directory which is "C:\Users\Amine>". so in order to make it work you have to change the working directory
C:\python script.py
'<html><head></head><body></body></html>'
This is why is it preferable to use absolute path.
error_log per Virtual Host?
php_value error_log "/var/log/httpd/vhost_php_error_log"
It works for me, but I have to change the permission of the log file.
or Apache will write the log to the its error_log
.
git stash -> merge stashed change with current changes
As suggested by @Brandan, here's what I needed to do to get around
error: Your local changes to the following files would be overwritten by merge:
file.txt
Please, commit your changes or stash them before you can merge.
Aborting
Follow this process:
git status # local changes to `file`
git stash list # further changes to `file` we want to merge
git commit -m "WIP" file
git stash pop
git commit -m "WIP2" file
git rebase -i HEAD^^ # I always use interactive rebase -- I'm sure you could do this in a single command with the simplicity of this process -- basically squash HEAD into HEAD^
# mark the second commit to squash into the first using your EDITOR
git reset HEAD^
And you'll be left with fully merged local changes to file
, ready to do further work/cleanup or make a single good commit. Or, if you know the merged contents of file
will be correct, you could write a fitting message and skip git reset HEAD^
.
How to change angular port from 4200 to any other
For Permanent:
Goto nodel_modules/angular-cli/commands/server.js
Search for var defaultPort = process.env.PORT || 4200; and change 4200 to anything else you want.
To Run Now:
ng serve --port 4500 (You an change 4500 to any number you want to use as your port)
IN-clause in HQL or Java Persistence Query Language
Are you using Hibernate's Query
object, or JPA? For JPA, it should work fine:
String jpql = "from A where name in (:names)";
Query q = em.createQuery(jpql);
q.setParameter("names", l);
For Hibernate's, you'll need to use the setParameterList:
String hql = "from A where name in (:names)";
Query q = s.createQuery(hql);
q.setParameterList("names", l);
Which characters make a URL invalid?
In your supplementary question you asked if www.example.com/file[/].html
is a valid URL.
That URL isn't valid because a URL is a type of URI and a valid URI must have a scheme like http:
(see RFC 3986).
If you meant to ask if http://www.example.com/file[/].html
is a valid URL then the answer is still no because the square bracket characters aren't valid there.
The square bracket characters are reserved for URLs in this format: http://[2001:db8:85a3::8a2e:370:7334]/foo/bar
(i.e. an IPv6 literal instead of a host name)
It's worth reading RFC 3986 carefully if you want to understand the issue fully.
How to pass macro definition from "make" command line arguments (-D) to C source code?
Call make
command this way:
make CFLAGS=-Dvar=42
And be sure to use $(CFLAGS)
in your compile command in the Makefile. As @jørgensen mentioned , putting the variable assignment after the make
command will override the CFLAGS
value already defined the Makefile.
Alternatively you could set -Dvar=42
in another variable than CFLAGS
and then reuse this variable in CFLAGS
to avoid completely overriding CFLAGS
.
Executing an EXE file using a PowerShell script
Not being a developer I found a solution in running multiple ps commands in one line. E.g:
powershell "& 'c:\path with spaces\to\executable.exe' -arguments ; second command ; etc
By placing a " (double quote) before the & (ampersand) it executes the executable. In none of the examples I have found this was mentioned. Without the double quotes the ps prompt opens and waits for input.
Angular2: child component access parent class variable/function
What about a little trickery like NgModel does with NgForm? You have to register your parent as a provider, then load your parent in the constructor of the child.
That way, you don't have to put [sharedList]
on all your children.
// Parent.ts
export var parentProvider = {
provide: Parent,
useExisting: forwardRef(function () { return Parent; })
};
@Component({
moduleId: module.id,
selector: 'parent',
template: '<div><ng-content></ng-content></div>',
providers: [parentProvider]
})
export class Parent {
@Input()
public sharedList = [];
}
// Child.ts
@Component({
moduleId: module.id,
selector: 'child',
template: '<div>child</div>'
})
export class Child {
constructor(private parent: Parent) {
parent.sharedList.push('Me.');
}
}
Then your HTML
<parent [sharedList]="myArray">
<child></child>
<child></child>
</parent>
You can find more information on the subject in the Angular documentation: https://angular.io/guide/dependency-injection-in-action#find-a-parent-component-by-injection
What are the differences between a superkey and a candidate key?
In nutshell: CANDIDATE KEY is a minimal SUPER KEY.
Where Super key is the combination of columns(or attributes) that uniquely identify any record(or tuple) in a relation(table) in RDBMS.
For instance, consider the following dependencies in a table having columns A, B, C, and D (Giving this table just for a quick example so not covering all dependencies that R could have).
Attribute set (Determinant)---Can Identify--->(Dependent)
A-----> AD
B-----> ABCD
C-----> CD
AC----->ACD
AB----->ABCD
ABC----->ABCD
BCD----->ABCD
Now, B, AB, ABC, BCD identifies all columns so those four qualify for the super key.
But, B?AB; B?ABC; B?BCD hence AB, ABC, and BCD disqualified for CANDIDATE KEY as their subsets could identify the relation, so they aren't minimal and hence only B is the candidate key, not the others.
One more thing Primary key is any one among the candidate keys.
Thanks for asking
How to call codeigniter controller function from view
Try this one.
Add this code in Your View file
$CI = & get_instance();
$result = $CI->FindFurnishName($pera);
Add code in Your controller File
public function FindFurnishName($furnish_filter)
{
$FindFurnishName = $this->index_modal->FindFurnishName($furnish_filter);
$FindFurnishName_val = '';
foreach($FindFurnishName as $AllRea)
{
$FindFurnishName_val .= ",".$AllRea->name;
}
return ltrim($FindFurnishName_val,',');
}
where
- FindFurnishName is name of function which is define in Your Controller.
- $pera is a option ( as your need).
Eclipse Bug: Unhandled event loop exception No more handles
The 'bug' is discussed here https://bugs.eclipse.org/bugs/show_bug.cgi?id=402983. A lot of discussion around 'multiple monitor' set-ups. I experienced the problem today(click in Eclipse (off-the-shelf ADT v22.3.0-887826) Package Explorer then click in java editor, and the "no more handles" error appears). It makes Eclipse unuseable.
Got me thinking that it is a monitor/graphics card problem on my win7 64bit PC, rather than a problem with Eclipse. I re-installed the graphics card (nVidia GTX480) and updated the drivers. Noticed multiple error dialog boxes(samsung monitor not found) relating to my monitor(in fact a single BX2440 monitor set-up) as i closed the system down for reboot. So, on re-boot I upgraded the monitor driver. Then booted again, and the problem has gone(at least for now).
BTW, I don't have Win 7 SP1 installed, so i don't think the 'full Windows update' solution discussed elsewhere on SO necessarily works for everyone.
how to check if the input is a number or not in C?
The sscanf() solution is better in terms of code lines. My answer here is a user-build function that does almost the same as sscanf(). Stores the converted number in a pointer and returns a value called "val". If val comes out as zero, then the input is in unsupported format, hence conversion failed. Hence, use the pointer value only when val is non-zero.
It works only if the input is in base-10 form.
#include <stdio.h>
#include <string.h>
int CONVERT_3(double* Amt){
char number[100];
// Input the Data
printf("\nPlease enter the amount (integer only)...");
fgets(number,sizeof(number),stdin);
// Detection-Conversion begins
int iters = strlen(number)-2;
int val = 1;
int pos;
double Amount = 0;
*Amt = 0;
for(int i = 0 ; i <= iters ; i++ ){
switch(i){
case 0:
if(number[i]=='+'){break;}
if(number[i]=='-'){val = 2; break;}
if(number[i]=='.'){val = val + 10; pos = 0; break;}
if(number[i]=='0'){Amount = 0; break;}
if(number[i]=='1'){Amount = 1; break;}
if(number[i]=='2'){Amount = 2; break;}
if(number[i]=='3'){Amount = 3; break;}
if(number[i]=='4'){Amount = 4; break;}
if(number[i]=='5'){Amount = 5; break;}
if(number[i]=='6'){Amount = 6; break;}
if(number[i]=='7'){Amount = 7; break;}
if(number[i]=='8'){Amount = 8; break;}
if(number[i]=='9'){Amount = 9; break;}
default:
switch(number[i]){
case '.':
val = val + 10;
pos = i;
break;
case '0':
Amount = (Amount)*10;
break;
case '1':
Amount = (Amount)*10 + 1;
break;
case '2':
Amount = (Amount)*10 + 2;
break;
case '3':
Amount = (Amount)*10 + 3;
break;
case '4':
Amount = (Amount)*10 + 4;
break;
case '5':
Amount = (Amount)*10 + 5;
break;
case '6':
Amount = (Amount)*10 + 6;
break;
case '7':
Amount = (Amount)*10 + 7;
break;
case '8':
Amount = (Amount)*10 + 8;
break;
case '9':
Amount = (Amount)*10 + 9;
break;
default:
val = 0;
}
}
if( (!val) | (val>20) ){val = 0; break;}// val == 0
}
if(val==1){*Amt = Amount;}
if(val==2){*Amt = 0 - Amount;}
if(val==11){
int exp = iters - pos;
long den = 1;
for( ; exp-- ; ){
den = den*10;
}
*Amt = Amount/den;
}
if(val==12){
int exp = iters - pos;
long den = 1;
for( ; exp-- ; ){
den = den*10;
}
*Amt = 0 - (Amount/den);
}
return val;
}
int main(void) {
double AM = 0;
int c = CONVERT_3(&AM);
printf("\n\n%d %lf\n",c,AM);
return(0);
}
Plot a legend outside of the plotting area in base graphics?
Maybe what you need is par(xpd=TRUE)
to enable things to be drawn outside the plot region. So if you do the main plot with bty='L'
you'll have some space on the right for a legend. Normally this would get clipped to the plot region, but do par(xpd=TRUE)
and with a bit of adjustment you can get a legend as far right as it can go:
set.seed(1) # just to get the same random numbers
par(xpd=FALSE) # this is usually the default
plot(1:3, rnorm(3), pch = 1, lty = 1, type = "o", ylim=c(-2,2), bty='L')
# this legend gets clipped:
legend(2.8,0,c("group A", "group B"), pch = c(1,2), lty = c(1,2))
# so turn off clipping:
par(xpd=TRUE)
legend(2.8,-1,c("group A", "group B"), pch = c(1,2), lty = c(1,2))
add onclick function to a submit button
if you need to do something before submitting data, you could use form's onsubmit.
<form method=post onsubmit="return doSomething()">
<input type=text name=text1>
<input type=submit>
</form>
React hooks useState Array
Try to keep your state minimal. There is no need to store
const initialValue = [
{ id: 0,value: " --- Select a State ---" }];
as state. Separate the permanent from the changing
const ALL_STATE_VALS = [
{ id: 0,value: " --- Select a State ---" }
{ id: 1, value: "Alabama" },
{ id: 2, value: "Georgia" },
{ id: 3, value: "Tennessee" }
];
Then you can store just the id as your state:
const StateSelector = () =>{
const [selectedStateOption, setselectedStateOption] = useState(0);
return (
<div>
<label>Select a State:</label>
<select>
{ALL_STATE_VALS.map((option, index) => (
<option key={option.id} selected={index===selectedStateOption}>{option.value}</option>
))}
</select>
</div>);
)
}
Java check to see if a variable has been initialized
Instance variables or fields, along with static variables, are assigned default values based on the variable type:
- int:
0
- char:
\u0000
or 0
- double:
0.0
- boolean:
false
- reference:
null
Just want to clarify that local variables (ie. declared in block, eg. method, for loop, while loop, try-catch, etc.) are not initialized to default values and must be explicitly initialized.
How do I point Crystal Reports at a new database
Use the Database menu and "Set Datasource Location" menu option to change the name or location of each table in a report.
This works for changing the location of a database, changing to a new database, and changing the location or name of an individual table being used in your report.
To change the datasource connection, go the Database menu and click Set Datasource Location.
- Change the Datasource Connection:
- From the Current Data Source list (the top box), click once on the datasource connection that you want to change.
- In the Replace with list (the bottom box), click once on the new datasource connection.
- Click Update.
- Change Individual Tables:
- From the Current Data Source list (the top box), expand the datasource connection that you want to change.
- Find the table for which you want to update the location or name.
- In the Replace with list (the bottom box), expand the new datasource connection.
- Find the new table you want to update to point to.
- Click Update.
- Note that if the table name has changed, the old table name will still appear in the Field Explorer even though it is now using the new table. (You can confirm this be looking at the Table Name of the table's properties in Current Data Source in Set Datasource Location. Screenshot http://i.imgur.com/gzGYVTZ.png) It's possible to rename the old table name to the new name from the context menu in Database Expert -> Selected Tables.
- Change Subreports:
- Repeat each of the above steps for any subreports you might have embedded in your report.
- Close the Set Datasource Location window.
- Any Commands or SQL Expressions:
- Go to the Database menu and click Database Expert.
- If the report designer used "Add Command" to write custom SQL it will be shown in the Selected Tables box on the right.
- Right click that command and choose "Edit Command".
- Check if that SQL is specifying a specific database. If so you might need to change it.
- Close the Database Expert window.
- In the Field Explorer pane on the right, right click any SQL Expressions.
- Check if the SQL Expressions are specifying a specific database. If so you might need to change it also.
- Save and close your Formula Editor window when you're done editing.
And try running the report again.
The key is to change the datasource connection first, then any tables you need to update, then the other stuff. The connection won't automatically change the tables underneath. Those tables are like goslings that've imprinted on the first large goose-like animal they see. They'll continue to bypass all reason and logic and go to where they've always gone unless you specifically manually change them.
To make it more convenient, here's a tip: You can "Show SQL Query" in the Database menu, and you'll see table names qualified with the database (like "Sales"."dbo"."Customers") for any tables that go straight to a specific database. That might make the hunting easier if you have a lot of stuff going on. When I tackled this problem I had to change each and every table to point to the new table in the new database.
Unexpected 'else' in "else" error
You need to rearrange your curly brackets. Your first statement is complete, so R interprets it as such and produces syntax errors on the other lines. Your code should look like:
if (dsnt<0.05) {
wilcox.test(distance[result=='nt'],distance[result=='t'],alternative=c("two.sided"),paired=TRUE)
} else if (dst<0.05) {
wilcox.test(distance[result=='nt'],distance[result=='t'],alternative=c("two.sided"),paired=TRUE)
} else {
t.test(distance[result=='nt'],distance[result=='t'],alternative=c("two.sided"),paired=TRUE)
}
To put it more simply, if you have:
if(condition == TRUE) x <- TRUE
else x <- FALSE
Then R reads the first line and because it is complete, runs that in its entirety. When it gets to the next line, it goes "Else? Else what?" because it is a completely new statement. To have R interpret the else as part of the preceding if statement, you must have curly brackets to tell R that you aren't yet finished:
if(condition == TRUE) {x <- TRUE
} else {x <- FALSE}
UILabel is not auto-shrinking text to fit label size
In Swift 4 (Programmatically):
let label = UILabel(frame: CGRect(x: 0, y: 0, width: 200.0, height: 200.0))
label.adjustsFontSizeToFitWidth = true
label.numberOfLines = 0
label.text = "Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book. It has survived not only five centuries, but also the leap into electronic typesetting, remaining essentially unchanged. It was popularised in the 1960s with the release of Letraset sheets containing Lorem Ipsum passages, and more recently with desktop publishing software like Aldus PageMaker including versions of Lorem Ipsum."
view.addSubview(label)
What techniques can be used to define a class in JavaScript, and what are their trade-offs?
ES2015 Classes
In the ES2015 specification, you can use the class syntax which is just sugar over the prototype system.
class Person {
constructor(name) {
this.name = name;
}
toString() {
return `My name is ${ this.name }.`;
}
}
class Employee extends Person {
constructor(name, hours) {
super(name);
this.hours = hours;
}
toString() {
return `${ super.toString() } I work ${ this.hours } hours.`;
}
}
Benefits
The main benefit is that static analysis tools find it easier to target this syntax. It is also easier for others coming from class-based languages to use the language as a polyglot.
Caveats
Be wary of its current limitations. To achieve private properties, one must resort to using Symbols or WeakMaps. In future releases, classes will most likely be expanded to include these missing features.
Support
Browser support isn't very good at the moment (supported by nearly everyone except IE), but you can use these features now with a transpiler like Babel.
Resources
Hiding a sheet in Excel 2007 (with a password) OR hide VBA code in Excel
Here is what you do in Excel 2003:
- In your sheet of interest, go to Format -> Sheet -> Hide and hide your sheet.
- Go to Tools -> Protection -> Protect Workbook, make sure Structure is selected, and enter your password of choice.
Here is what you do in Excel 2007:
- In your sheet of interest, go to Home ribbon -> Format -> Hide & Unhide -> Hide Sheet and hide your sheet.
- Go to Review ribbon -> Protect Workbook, make sure Structure is selected, and enter your password of choice.
Once this is done, the sheet is hidden and cannot be unhidden without the password. Make sense?
If you really need to keep some calculations secret, try this: use Access (or another Excel workbook or some other DB of your choice) to calculate what you need calculated, and export only the "unclassified" results to your Excel workbook.
ARM compilation error, VFP registers used by executable, not object file
This answer may appear at the surface to be unrelated, but there is an indirect cause of this error message.
First, the "Uses VFP register..." error message is directly caused from mixing mfloat-abi=soft and mfloat-abi=hard options within your build. This setting must be consistent for all objects that are to be linked. This fact is well covered in the other answers to this question.
The indirect cause of this error may be due to the Eclipse editor getting confused by a self-inflicted error in the project's ".cproject" file. The Eclipse editor frequently reswizzles file links and sometimes it breaks itself when you make changes to your directory structures or file locations. This can also affect the path settings to your gcc compiler - and only for a subset of your project's files. While I'm not yet sure of exactly what causes this failure, replacing the .cproject file with a backup copy corrected this problem for me. In my case I noticed .java.null.pointer errors after adding an include directory path and started receiving the "VFP register error" messages out of the blue. In the build log I noticed that a different path to the gcc compiler was being used for some of my sources that were local to the workspace, but not all of them!? The two gcc compilers were using different float settings for unknown reasons - hence the VFP register error.
I compared the .cproject settings with a older copy and observed differences in entries for the sources causing the trouble - even though the overriding of project settings was disabled. By replacing the .cproject file with the old version the problem went away, and I'm leaving this answer as a reminder of what happened.
How do I perform a JAVA callback between classes?
Use the observer pattern. It works like this:
interface MyListener{
void somethingHappened();
}
public class MyForm implements MyListener{
MyClass myClass;
public MyForm(){
this.myClass = new MyClass();
myClass.addListener(this);
}
public void somethingHappened(){
System.out.println("Called me!");
}
}
public class MyClass{
private List<MyListener> listeners = new ArrayList<MyListener>();
public void addListener(MyListener listener) {
listeners.add(listener);
}
void notifySomethingHappened(){
for(MyListener listener : listeners){
listener.somethingHappened();
}
}
}
You create an interface which has one or more methods to be called when some event happens. Then, any class which needs to be notified when events occur implements this interface.
This allows more flexibility, as the producer is only aware of the listener interface, not a particular implementation of the listener interface.
In my example:
MyClass
is the producer here as its notifying a list of listeners.
MyListener
is the interface.
MyForm
is interested in when somethingHappened
, so it is implementing MyListener
and registering itself with MyClass
. Now MyClass
can inform MyForm
about events without directly referencing MyForm
. This is the strength of the observer pattern, it reduces dependency and increases reusability.
How to create text file and insert data to that file on Android
Check the android documentation. It's in fact not much different than standard java io file handling so you could also check that documentation.
An example from the android documentation:
String FILENAME = "hello_file";
String string = "hello world!";
FileOutputStream fos = openFileOutput(FILENAME, Context.MODE_PRIVATE);
fos.write(string.getBytes());
fos.close();
How to lazy load images in ListView in Android
Well, image loading time from the Internet has many solutions. You may also use the library Android-Query. It will give you all the required activity. Make sure what you want to do and read the library wiki page. And solve the image loading restriction.
This is my code:
@Override
public View getView(int position, View convertView, ViewGroup parent) {
View v = convertView;
if (v == null) {
LayoutInflater vi = (LayoutInflater)getSystemService(Context.LAYOUT_INFLATER_SERVICE);
v = vi.inflate(R.layout.row, null);
}
ImageView imageview = (ImageView) v.findViewById(R.id.icon);
AQuery aq = new AQuery(convertView);
String imageUrl = "http://www.vikispot.com/z/images/vikispot/android-w.png";
aq.id(imageview).progress(this).image(imageUrl, true, true, 0, 0, new BitmapAjaxCallback() {
@Override
public void callback(String url, ImageView iv, Bitmap bm, AjaxStatus status) {
iv.setImageBitmap(bm);
}
));
return v;
}
It should be solve your lazy loading problem.
Redirect on select option in select box
Because the first option is already selected, the change event is never fired. Add an empty value as the first one and check for empty in the location assignment.
Here's an example:
https://jsfiddle.net/bL5sq/
_x000D_
_x000D_
<select onchange="this.options[this.selectedIndex].value && (window.location = this.options[this.selectedIndex].value);">_x000D_
<option value="">Select...</option>_x000D_
<option value="https://google.com">Google</option>_x000D_
<option value="https://yahoo.com">Yahoo</option>_x000D_
</select>
_x000D_
_x000D_
_x000D_
Adding a new value to an existing ENUM Type
Complementing @Dariusz 1
For Rails 4.2.1, there's this doc section:
== Transactional Migrations
If the database adapter supports DDL transactions, all migrations will
automatically be wrapped in a transaction. There are queries that you
can't execute inside a transaction though, and for these situations
you can turn the automatic transactions off.
class ChangeEnum < ActiveRecord::Migration
disable_ddl_transaction!
def up
execute "ALTER TYPE model_size ADD VALUE 'new_value'"
end
end
How do I correct the character encoding of a file?
Follow these steps with Notepad++
1- Copy the original text
2- In Notepad++, open new file, change Encoding -> pick an encoding you think the original text follows. Try as well the encoding "ANSI" as sometimes Unicode files are read as ANSI by certain programs
3- Paste
4- Then to convert to Unicode by going again over the same menu: Encoding -> "Encode in UTF-8" (Not "Convert to UTF-8") and hopefully it will become readable
The above steps apply for most languages. You just need to guess the original encoding before pasting in notepad++, then convert through the same menu to an alternate Unicode-based encoding to see if things become readable.
Most languages exist in 2 forms of encoding: 1- The old legacy ANSI (ASCII) form, only 8 bits, was used initially by most computers. 8 bits only allowed 256 possibilities, 128 of them where the regular latin and control characters, the final 128 bits were read differently depending on the PC language settings 2- The new Unicode standard (up to 32 bit) give a unique code for each character in all currently known languages and plenty more to come. if a file is unicode it should be understood on any PC with the language's font installed. Note that even UTF-8 goes up to 32 bit and is just as broad as UTF-16 and UTF-32 only it tries to stay 8 bits with latin characters just to save up disk space
What's the correct way to convert bytes to a hex string in Python 3?
Python has bytes-to-bytes standard codecs that perform convenient transformations like quoted-printable (fits into 7bits ascii), base64 (fits into alphanumerics), hex escaping, gzip and bz2 compression. In Python 2, you could do:
b'foo'.encode('hex')
In Python 3, str.encode
/ bytes.decode
are strictly for bytes<->str conversions. Instead, you can do this, which works across Python 2 and Python 3 (s/encode/decode/g for the inverse):
import codecs
codecs.getencoder('hex')(b'foo')[0]
Starting with Python 3.4, there is a less awkward option:
codecs.encode(b'foo', 'hex')
These misc codecs are also accessible inside their own modules (base64, zlib, bz2, uu, quopri, binascii); the API is less consistent, but for compression codecs it offers more control.
Change UITableView height dynamically
Rob's solution is very nice, only thing that in his -(void)adjustHeightOfTableview
method the calling of
[self.view needsUpdateConstraints]
does nothing, it just returns a flag, instead calling
[self.view setNeedsUpdateConstraints]
will make the desired effect.
Place input box at the center of div
Here's a rather unconventional way of doing it:
#inputcontainer
{
display:table-cell; //display like a <td> to make the vertical-align work
text-align:center; //centre the input horizontally
vertical-align:middle; //centre the input vertically
width:200px; //widen the div for demo purposes
height:200px; //make the div taller for demo purposes
background:green; //change the background of the div for demo purposes
}
It might not be the best way to do it, and margin? won't work, but it does the job. If you need to use margin, then you could wrap the div that displays as a table cell in another 'normal' div.
JSFiddle: http://jsfiddle.net/qw4QW/
Cannot use Server.MapPath
System.Web.HttpContext.Current.Server.MapPath("~/")
gives null if we call it from a thread.
So, Try to use
System.Web.Hosting.HostingEnvironment.MapPath("~/")
Start service in Android
I like to make it more dynamic
Class<?> serviceMonitor = MyService.class;
private void startMyService() { context.startService(new Intent(context, serviceMonitor)); }
private void stopMyService() { context.stopService(new Intent(context, serviceMonitor)); }
do not forget the Manifest
<service android:enabled="true" android:name=".MyService.class" />
Running MSBuild fails to read SDKToolsPath
Short answer: In the .csproj file, there is a way to specify the path to sgen.exe, using SGenToolPath:
<Project DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003" ToolsVersion="14.0">
<PropertyGroup>
<SGenToolPath>C:\Program Files (x86)\Microsoft SDKs\Windows\v10.0A\bin\NETFX 4.6 Tools</SGenToolPath>
</PropertyGroup>
Your path may be different, but SGenToolPath is what you want.
For a list of other common MSBuild Project properties, see: https://msdn.microsoft.com/en-us/library/bb629394.aspx
We ended up using this SGenToolPath setting in the .csproj file, instead of editing the registry values on the build server. Editing the registry values on my local machine had worked as well, but was a bit more complicated and we didn't want to mess with the registry on the build server.
For the registry: In that case the problem was that the SDK40ToolsPath(s) under HKLM\SOFTWARE\Wow6432Node\Microsoft\MSBuild
were pointing to a registry value $(Registry:HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Microsoft SDKs\Windows\v8.0A\WinSDK-NetFx40Tools-x86@InstallationFolder) which did not exist. I just replaced that with the actual path directly.
input[type='text'] CSS selector does not apply to default-type text inputs?
By CSS specifications, browsers may or may not use information about default attributes; mostly the don’t. The relevant clause in the CSS 2.1 spec is 5.8.2 Default attribute values in DTDs. In CSS 3 Selectors, it’s clause 6.3.4, with the same name. It recommends: “Selectors should be designed so that they work whether or not the default values are included in the document tree.”
It is generally best to explicitly specify essential attributes such as type=text
instead of defaulting them. The reason is that there is no simple reliable way to refer to the input
elements with defaulted type
attribute.
jQuery: get parent tr for selected radio button
Try this.
You don't need to prefix attribute name by @
in jQuery selector. Use closest()
method to get the closest parent element matching the selector.
$("#MwDataList input[name=selectRadioGroup]:checked").closest('tr');
You can simplify your method like this
function getSelectedRowGuid() {
return GetRowGuid(
$("#MwDataList > input:radio[@name=selectRadioGroup]:checked :parent tr"));
}
closest()
- Gets the first element that matches the selector, beginning at the current element and progressing up through the DOM tree.
As a side note, the ids of the elements should be unique on the page so try to avoid having same ids for radio buttons which I can see in your markup. If you are not going to use the ids then just remove it from the markup.
Python: convert string to byte array
encode function can help you here, encode returns an encoded version of the string
In [44]: str = "ABCD"
In [45]: [elem.encode("hex") for elem in str]
Out[45]: ['41', '42', '43', '44']
or you can use array module
In [49]: import array
In [50]: print array.array('B', "ABCD")
array('B', [65, 66, 67, 68])
Android turn On/Off WiFi HotSpot programmatically
APManager - Access Point Manager
Step 1 : Add the jcenter repository to your build file
allprojects {
repositories {
...
jcenter()
}
}
Step 2 : Add the dependency
dependencies {
implementation 'com.vkpapps.wifimanager:APManager:1.0.0'
}
Step 3 use in your app
APManager apManager = APManager.getApManager(this);
apManager.turnOnHotspot(this, new APManager.OnSuccessListener() {
@Override
public void onSuccess(String ssid, String password) {
//write your logic
}
}, new APManager.OnFailureListener() {
@Override
public void onFailure(int failureCode, @Nullable Exception e) {
//handle error like give access to location permission,write system setting permission,
//disconnect wifi,turn off already created hotspot,enable GPS provider
//or use DefaultFailureListener class to handle automatically
}
});
check out source code
https://github.com/vijaypatidar/AndroidWifiManager
Change the Theme in Jupyter Notebook?
Simple, global change of Jupyter font size and inner & outer background colors (this change will affect all notebooks).
In Windows, find config directory by running a command:
jupyter --config-dir
In Linux it is ~/.jupyter
In this directory create subfolder custom
Create file custom.css
and paste:
/* Change outer background and make the notebook take all available width */
.container {
width: 99% !important;
background: #DDC !important;
}
/* Change inner background (CODE) */
div.input_area {
background: #F4F4E2 !important;
font-size: 16px !important;
}
/* Change global font size (CODE) */
.CodeMirror {
font-size: 16px !important;
}
/* Prevent the edit cell highlight box from getting clipped;
* important so that it also works when cell is in edit mode */
div.cell.selected {
border-left-width: 1px !important;
}
Finally - restart Jupyter. Result:
How to run ssh-add on windows?
In order to run ssh-add
on Windows one could install git using choco install git
. The ssh-add
command is recognized once C:\Program Files\Git\usr\bin
has been added as a PATH variable and the command prompt has been restarted:
C:\Users\user\Desktop\repository>ssh-add .ssh/id_rsa
Enter passphrase for .ssh/id_rsa:
Identity added: .ssh/id_rsa (.ssh/id_rsa)
C:\Users\user\Desktop\repository>
Pandas left outer join multiple dataframes on multiple columns
Merge them in two steps, df1
and df2
first, and then the result of that to df3
.
In [33]: s1 = pd.merge(df1, df2, how='left', on=['Year', 'Week', 'Colour'])
I dropped year from df3 since you don't need it for the last join.
In [39]: df = pd.merge(s1, df3[['Week', 'Colour', 'Val3']],
how='left', on=['Week', 'Colour'])
In [40]: df
Out[40]:
Year Week Colour Val1 Val2 Val3
0 2014 A Red 50 NaN NaN
1 2014 B Red 60 NaN 60
2 2014 B Black 70 100 10
3 2014 C Red 10 20 NaN
4 2014 D Green 20 NaN 20
[5 rows x 6 columns]
Hashmap does not work with int, char
Hashmaps can only use classes
, not primitives
. This page from programmerinterview.com might be of use in guiding you to finding the answer. To be honest, I haven't figured out the answer to this problem in detail myself.
Where to find "Microsoft.VisualStudio.TestTools.UnitTesting" missing dll?
I got this problem after moving a project and deleting it's packages folder.
Nuget was showning that MSTest.TestAdapter and MSTest.TestFramework v 1.3.2 was installed.
The fix seemed to be to open VS as administrator and build
After that I was able to re-open and build without having admin priviledge.
Executing multiple commands from a Windows cmd script
Using double ampersands will run the second command, only if the first one succeeds:
cd Desktop/project-directory && atom .
Where as, using only one ampersand will attempt to run both commands, even if the first fails:
cd Desktop/project-directory & atom .
How to join two sets in one line without using "|"
Assuming you also can't use s.union(t)
, which is equivalent to s | t
, you could try
>>> from itertools import chain
>>> set(chain(s,t))
set([1, 2, 3, 4, 5, 6])
Or, if you want a comprehension,
>>> {i for j in (s,t) for i in j}
set([1, 2, 3, 4, 5, 6])
How to use zIndex in react-native
Use elevation
instead of zIndex
for android devices
elevatedElement: {
zIndex: 3, // works on ios
elevation: 3, // works on android
}
This worked fine for me!
Can I add a custom attribute to an HTML tag?
Yes, you can use data-*
attribute.
The data-*
attribute is used to store custom data private to the page or application.
<ul>
<li data-pageNumber="1"> 1 </li>
<li data-pageNumber="2"> 2 </li>
<li data-pageNumber="3"> 3 </li>
</ul
How can I query a value in SQL Server XML column
Useful tip. Query a value in SQL Server XML column (XML with namespace)
e.g.
Table [dbo].[Log_XML] contains columns Parametrs (xml),TimeEdit (datetime)
e.g. XML in Parametrs:
<ns0:Record xmlns:ns0="http://Integration">
<MATERIAL>10</MATERIAL>
<BATCH>A1</BATCH>
</ns0:Record>
e.g. Query:
select
Parametrs,TimeEdit
from
[dbo].[Log_XML]
where
Parametrs.value('(//*:Record/BATCH)[1]', 'varchar(max)') like '%A1%'
ORDER BY TimeEdit DESC
Is System.nanoTime() completely useless?
I did a bit of searching and found that if one is being pedantic then yes it might be considered useless...in particular situations...it depends on how time sensitive your requirements are...
Check out this quote from the Java Sun site:
The real-time clock and
System.nanoTime() are both based on
the same system call and thus the same
clock.
With Java RTS, all time-based APIs
(for example, Timers, Periodic
Threads, Deadline Monitoring, and so
forth) are based on the
high-resolution timer. And, together
with real-time priorities, they can
ensure that the appropriate code will
be executed at the right time for
real-time constraints. In contrast,
ordinary Java SE APIs offer just a few
methods capable of handling
high-resolution times, with no
guarantee of execution at a given
time. Using System.nanoTime() between
various points in the code to perform
elapsed time measurements should
always be accurate.
Java also has a caveat for the nanoTime() method:
This method can only be used to
measure elapsed time and is not
related to any other notion of system
or wall-clock time. The value returned
represents nanoseconds since some
fixed but arbitrary time (perhaps in
the future, so values may be
negative). This method provides
nanosecond precision, but not
necessarily nanosecond accuracy. No
guarantees are made about how
frequently values change. Differences
in successive calls that span greater
than approximately 292.3 years (263
nanoseconds) will not accurately
compute elapsed time due to numerical
overflow.
It would seem that the only conclusion that can be drawn is that nanoTime() cannot be relied upon as an accurate value. As such, if you do not need to measure times that are mere nano seconds apart then this method is good enough even if the resulting returned value is negative. However, if you're needing higher precision, they appear to recommend that you use JAVA RTS.
So to answer your question...no nanoTime() is not useless....its just not the most prudent method to use in every situation.
What is the difference between a schema and a table and a database?
Contrary to some of the above answers, here is my understanding based on experience with each of them:
- MySQL:
database/schema :: table
- SQL Server:
database :: (schema/namespace ::) table
- Oracle:
database/schema/user :: (tablespace ::) table
Please correct me on whether tablespace is optional or not with Oracle, it's been a long time since I remember using them.
How can I hide or encrypt JavaScript code?
While everyone will generally agree that Javascript encryption is a bad idea, there are a few small use cases where slowing down the attack is better than nothing.
You can start with YUI Compressor (as @Ben Alpert) said, or JSMin, Uglify, or many more.
However, the main case in which I want to really 'hide stuff' is when I'm publishing an email address. Note, there is the problem of Chrome when you click on 'inspect element'. It will show your original code: every time. This is why obfuscation is generally regarded as being a better way to go.
On that note, I take a two pronged attack, purely to slow down spam bots. I Obfuscate/minify the js and then run it again through an encoder (again, this second step is completely pointless in chrome).
While not exactly a pure Javascript encoder, the best html encoder I have found is http://hivelogic.com/enkoder/. It will turn this:
<script type="text/javascript">
//<![CDATA[
<!--
var c=function(e) { var m="mail" + "to:webmaster";var a="somedomain"; e.href = m+"@"+a+".com";
};
//-->
//]]>
</script>
<a href="#" onclick="return c(this);"><img src="images/email.png" /></a>
into this:
<script type="text/javascript">
//<![CDATA[
<!--
var x="function f(x){var i,o=\"\",ol=x.length,l=ol;while(x.charCodeAt(l/13)!" +
"=50){try{x+=x;l+=l;}catch(e){}}for(i=l-1;i>=0;i--){o+=x.charAt(i);}return o" +
".substr(0,ol);}f(\")87,\\\"meozp?410\\\\=220\\\\s-dvwggd130\\\\#-2o,V_PY420" +
"\\\\I\\\\\\\\_V[\\\\\\\\620\\\\o710\\\\RB\\\\\\\\610\\\\JAB620\\\\720\\\\n\\"+
"\\{530\\\\410\\\\WJJU010\\\\|>snnn|j5J(771\\\\p{}saa-.W)+T:``vk\\\"\\\\`<02" +
"0\\\\!610\\\\'Dr\\\\010\\\\630\\\\400\\\\620\\\\700\\\\\\\\\\\\N730\\\\,530" +
"\\\\2S16EF600\\\\;420\\\\9ZNONO1200\\\\/000\\\\`'7400\\\\%n\\\\!010\\\\hpr\\"+
"\\= -cn720\\\\a(ce230\\\\500\\\\f730\\\\i,`200\\\\630\\\\[YIR720\\\\]720\\\\"+
"r\\\\720\\\\h][P]@JHADY310\\\\t230\\\\G500\\\\VBT230\\\\200\\\\Clxhh{tzra/{" +
"g0M0$./Pgche%Z8i#p`v^600\\\\\\\\\\\\R730\\\\Q620\\\\030\\\\730\\\\100\\\\72" +
"0\\\\530\\\\700\\\\720\\\\M410\\\\N730\\\\r\\\\530\\\\400\\\\4420\\\\8OM771" +
"\\\\`4400\\\\$010\\\\t\\\\120\\\\230\\\\r\\\\610\\\\310\\\\530\\\\e~o120\\\\"+
"RfJjn\\\\020\\\\lZ\\\\\\\\CZEWCV771\\\\v5lnqf2R1ox771\\\\p\\\"\\\\tr\\\\220" +
"\\\\310\\\\420\\\\600\\\\OSG300\\\\700\\\\410\\\\320\\\\410\\\\120\\\\620\\" +
"\\q)5<: 0>+\\\"(f};o nruter};))++y(^)i(tAedoCrahc.x(edoCrahCmorf.gnirtS=+o;" +
"721=%y;++y)87<i(fi{)++i;l<i;0=i(rof;htgnel.x=l,\\\"\\\"=o,i rav{)y,x(f noit" +
"cnuf\")" ;
while(x=eval(x));
//-->
//]]>
</script>
Maybe it's enough to slow down a few spam bots. I haven't had any spam come through using this (!yet).
How to list the files inside a JAR file?
One more for the road that's a bit more flexible for matching specific filenames because it uses wildcard globbing. In a functional style this could resemble:
import java.io.IOException;
import java.net.URISyntaxException;
import java.nio.file.FileSystem;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.function.Consumer;
import static java.nio.file.FileSystems.getDefault;
import static java.nio.file.FileSystems.newFileSystem;
import static java.util.Collections.emptyMap;
/**
* Responsible for finding file resources.
*/
public class ResourceWalker {
/**
* Globbing pattern to match font names.
*/
public static final String GLOB_FONTS = "**.{ttf,otf}";
/**
* @param directory The root directory to scan for files matching the glob.
* @param c The consumer function to call for each matching path
* found.
* @throws URISyntaxException Could not convert the resource to a URI.
* @throws IOException Could not walk the tree.
*/
public static void walk(
final String directory, final String glob, final Consumer<Path> c )
throws URISyntaxException, IOException {
final var resource = ResourceWalker.class.getResource( directory );
final var matcher = getDefault().getPathMatcher( "glob:" + glob );
if( resource != null ) {
final var uri = resource.toURI();
final Path path;
FileSystem fs = null;
if( "jar".equals( uri.getScheme() ) ) {
fs = newFileSystem( uri, emptyMap() );
path = fs.getPath( directory );
}
else {
path = Paths.get( uri );
}
try( final var walk = Files.walk( path, 10 ) ) {
for( final var it = walk.iterator(); it.hasNext(); ) {
final Path p = it.next();
if( matcher.matches( p ) ) {
c.accept( p );
}
}
} finally {
if( fs != null ) { fs.close(); }
}
}
}
}
Consider parameterizing the file extensions, left an exercise for the reader.
Be careful with Files.walk
. According to the documentation:
This method must be used within a try-with-resources statement or similar control structure to ensure that the stream's open directories are closed promptly after the stream's operations have completed.
Likewise, newFileSystem
must be closed, but not before the walker has had a chance to visit the file system paths.
Removing underline with href attribute
Add a style with the attribute text-decoration:none;
:
There are a number of different ways of doing this.
Inline style:
<a href="xxx.html" style="text-decoration:none;">goto this link</a>
Inline stylesheet:
<html>
<head>
<style type="text/css">
a {
text-decoration:none;
}
</style>
</head>
<body>
<a href="xxx.html">goto this link</a>
</body>
</html>
External stylesheet:
<html>
<head>
<link rel="Stylesheet" href="stylesheet.css" />
</head>
<body>
<a href="xxx.html">goto this link</a>
</body>
</html>
stylesheet.css:
a {
text-decoration:none;
}
Is there a workaround for ORA-01795: maximum number of expressions in a list is 1000 error?
**Divide a list to lists of n size**
import java.util.AbstractList;
import java.util.ArrayList;
import java.util.List;
public final class PartitionUtil<T> extends AbstractList<List<T>> {
private final List<T> list;
private final int chunkSize;
private PartitionUtil(List<T> list, int chunkSize) {
this.list = new ArrayList<>(list);
this.chunkSize = chunkSize;
}
public static <T> PartitionUtil<T> ofSize(List<T> list, int chunkSize) {
return new PartitionUtil<>(list, chunkSize);
}
@Override
public List<T> get(int index) {
int start = index * chunkSize;
int end = Math.min(start + chunkSize, list.size());
if (start > end) {
throw new IndexOutOfBoundsException("Index " + index + " is out of the list range <0," + (size() - 1) + ">");
}
return new ArrayList<>(list.subList(start, end));
}
@Override
public int size() {
return (int) Math.ceil((double) list.size() / (double) chunkSize);
}
}
Function call :
List<List<String>> containerNumChunks = PartitionUtil.ofSize(list, 999)
more details: https://e.printstacktrace.blog/divide-a-list-to-lists-of-n-size-in-Java-8/
How to run .sh on Windows Command Prompt?
Install GIT. During installation of GIT, add GIT Bash to windows context menu by selecting its option. After installation right click in your folder select GIT Bash Here
(see attached pic) and use your sh command like for example:
sh test.sh
Open another application from your own (intent)
Since applications aren't allowed to change many of the phone settings, you can open a settings activity just like another application.
Look at you LogCat output after you actually modified the setting manually:
INFO/ActivityManager(1306): Starting activity: Intent { act=android.intent.action.MAIN cmp=com.android.settings/.DevelopmentSettings } from pid 1924
Then use this to display the settings page from your app:
String SettingsPage = "com.android.settings/.DevelopmentSettings";
try
{
Intent intent = new Intent(Intent.ACTION_MAIN);
intent.setComponent(ComponentName.unflattenFromString(SettingsPage));
intent.addCategory(Intent.CATEGORY_LAUNCHER );
startActivity(intent);
}
catch (ActivityNotFoundException e)
{
log it
}
Calculate Age in MySQL (InnoDb)
If the value is stored as a DATETIME data type:
SELECT YEAR(CURRENT_TIMESTAMP) - YEAR(dob) - (RIGHT(CURRENT_TIMESTAMP, 5) < RIGHT(dob, 5)) as age
FROM YOUR_TABLE
Less precise when you consider leap years:
SELECT DATEDIFF(CURRENT_DATE, STR_TO_DATE(t.birthday, '%d-%m-%Y'))/365 AS ageInYears
FROM YOUR_TABLE t
What is Inversion of Control?
But I think you have to be very careful with it. If you will overuse this pattern, you will make very complicated design and even more complicated code.
Like in this example with TextEditor: if you have only one SpellChecker maybe it is not really necessary to use IoC ? Unless you need to write unit tests or something ...
Anyway: be reasonable. Design pattern are good practices but not Bible to be preached. Do not stick it everywhere.
How to run Conda?
Similar to the above, remember that you could have miniconda
instead of conda, so you might want to add
export PATH=${PATH}:/Users/davidfortini/miniconda3/bin
to .zshrc
or .bash_profile
and then reboot the terminal.
Javascript - How to detect if document has loaded (IE 7/Firefox 3)
There's no need for all the code mentioned by galambalazs. The cross-browser way to do it in pure JavaScript is simply to test document.readyState
:
if (document.readyState === "complete") { init(); }
This is also how jQuery does it.
Depending on where the JavaScript is loaded, this can be done inside an interval:
var readyStateCheckInterval = setInterval(function() {
if (document.readyState === "complete") {
clearInterval(readyStateCheckInterval);
init();
}
}, 10);
In fact, document.readyState
can have three states:
Returns "loading" while the document is loading, "interactive" once it is finished parsing but still loading sub-resources, and "complete" once it has loaded.
-- document.readyState at Mozilla Developer Network
So if you only need the DOM to be ready, check for document.readyState === "interactive"
. If you need the whole page to be ready, including images, check for document.readyState === "complete"
.
How to determine a user's IP address in node
I realize this has been answered to death, but here's a modern ES6 version I wrote that follows airbnb-base eslint standards.
const getIpAddressFromRequest = (request) => {
let ipAddr = request.connection.remoteAddress;
if (request.headers && request.headers['x-forwarded-for']) {
[ipAddr] = request.headers['x-forwarded-for'].split(',');
}
return ipAddr;
};
The X-Forwarded-For header may contain a comma-separated list of proxy IPs. The order is client,proxy1,proxy2,...,proxyN. In the real world, people implement proxies that may supply whatever they want in this header. If you are behind a load balancer or something, you can at least trust the first IP in the list is at least whatever proxy some request came through.
Gradle: Execution failed for task ':processDebugManifest'
In my case I had written the tag twice. That was my only mistake It was before code`
<uses-permission android:name="android.permission.SYSTEM_ALERT_WINDOW"/>
<uses-permission android:name="android.permission.RECORD_AUDIO"/>
<application tools:targetApi="28" tools:ignore="GoogleAppIndexingWarning" android:networkSecurityConfig="@xml/react_native_config" />
<application application tools:targetApi="28" tools:ignore="GoogleAppIndexingWarning" android:networkSecurityConfig="@xml/react_native_config" >
</application>
`
Just removing the application tag solved my problem.
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools">
<uses-permission android:name="android.permission.SYSTEM_ALERT_WINDOW"/>
<application tools:targetApi="28" tools:ignore="GoogleAppIndexingWarning" android:networkSecurityConfig="@xml/react_native_config" />
</manifest>
The points you should have only one tag; can have more than one and , but one tag. That's what I know at this moment :)
Loop through array of values with Arrow Function
One statement can be written as such:
someValues.forEach(x => console.log(x));
or multiple statements can be enclosed in {}
like this:
someValues.forEach(x => { let a = 2 + x; console.log(a); });
What is the correct way to represent null XML elements?
You use xsi:nil
when your schema semantics indicate that an element has a default value, and that the default value should be used if the element isn't present. I have to assume that there are smart people to whom the preceding sentence is not a self-evidently terrible idea, but it sounds like nine kinds of bad to me. Every XML format I've ever worked with represents null values by omitting the element. (Or attribute, and good luck marking an attribute with xsi:nil
.)
Omitting one Setter/Getter in Lombok
According to @Data description you can use:
All generated getters and setters will be public. To override the
access level, annotate the field or class with an explicit @Setter
and/or @Getter annotation. You can also use this annotation (by
combining it with AccessLevel.NONE) to suppress generating a getter
and/or setter altogether.
Best place to insert the Google Analytics code
If you want your scripts to load after page has been rendered, you can use:
function getScript(a, b) {
var c = document.createElement("script");
c.src = a;
var d = document.getElementsByTagName("head")[0],
done = false;
c.onload = c.onreadystatechange = function() {
if (!done && (!this.readyState || this.readyState == "loaded" || this.readyState == "complete")) {
done = true;
b();
c.onload = c.onreadystatechange = null;
d.removeChild(c)
}
};
d.appendChild(c)
}
//call the function
getScript("http://www.google-analytics.com/ga.js", function() {
// do stuff after the script has loaded
});
SQLException: No suitable Driver Found for jdbc:oracle:thin:@//localhost:1521/orcl
First, if you develop an application with Java EE 6 within a server (JBoss),
you should better use a DataSource. Then you can obtain the Connection from this DataSource. It's better to use connections pools.
Then, as of JBoss AS 7, the JDBC driver must be declared as a module.
This is described here.
With OJDBC 6 (11.x), the name of the driver should be "oracle.jdbc.OracleDriver".
This is the name registered in SPI mode (see the content of this file : META-INF/services/java.sql.Driver).
Since Java 6 and JDBC 4.0, the JDBC Drivers are auto-registered.
Finally you will have to declare a DataSource within JBoss : DataSource configuration.
References :
- Establishing a Connection (link) (JDBC 4.0 <=> Java 6)
- JDBC 4.0 Enhancements in Java SE 6 > Auto-Loading of JDBC Driver (link)
HRESULT: 0x80040154 (REGDB_E_CLASSNOTREG))
Just looking at the message it sounds like one or more of the components that you reference, or one or more of their dependencies is not registered properly.
If you know which component it is you can use regsvr32.exe to register it, just open a command prompt, go to the directory where the component is and type regsvr32 filename.dll
(assuming it's a dll), if it works, try to run the code again otherwise come back here with the error.
If you don't know which component it is, try re-installing/repairing the GIS software (I assume you've installed some GIS software that includes the component you're trying to use).
How do I automatically set the $DISPLAY variable for my current session?
do you use Bash? Go to the file .bashrc in your home directory and set the variable, then export it.
DISPLAY=localhost:0.0 ; export DISPLAY
you can use /etc/bashrc if you want to do it for all the users.
You may also want to look in ~/.bash_profile and /etc/profile
EDIT:
function get_xserver ()
{
case $TERM in
xterm )
XSERVER=$(who am i | awk '{print $NF}' | tr -d ')''(' )
XSERVER=${XSERVER%%:*}
;;
aterm | rxvt)
;;
esac
}
if [ -z ${DISPLAY:=""} ]; then
get_xserver
if [[ -z ${XSERVER} || ${XSERVER} == $(hostname) || \
${XSERVER} == "unix" ]]; then
DISPLAY=":0.0" # Display on local host.
else
DISPLAY=${XSERVER}:0.0 # Display on remote host.
fi
fi
export DISPLAY
How do I clear inner HTML
The problem appears to be that the global symbol clear
is already in use and your function doesn't succeed in overriding it. If you change that name to something else (I used blah
), it works just fine:
Live: Version using clear
which fails | Version using blah
which works
<html>
<head>
<title>lala</title>
</head>
<body>
<h1 onmouseover="go('The dog is in its shed')" onmouseout="blah()">lalala</h1>
<div id="goy"></div>
<script type="text/javascript">
function go(what) {
document.getElementById("goy").innerHTML = what;
}
function blah() {
document.getElementById("goy").innerHTML = "";
}
</script>
</body>
</html>
This is a great illustration of the fundamental principal: Avoid global variables wherever possible. The global namespace in browsers is incredibly crowded, and when conflicts occur, you get weird bugs like this.
A corollary to that is to not use old-style onxyz=...
attributes to hook up event handlers, because they require globals. Instead, at least use code to hook things up: Live Copy
<html>
<head>
<title>lala</title>
</head>
<body>
<h1 id="the-header">lalala</h1>
<div id="goy"></div>
<script type="text/javascript">
// Scoping function makes the declarations within
// it *not* globals
(function(){
var header = document.getElementById("the-header");
header.onmouseover = function() {
go('The dog is in its shed');
};
header.onmouseout = clear;
function go(what) {
document.getElementById("goy").innerHTML = what;
}
function clear() {
document.getElementById("goy").innerHTML = "";
}
})();
</script>
</body>
</html>
...and even better, use DOM2's addEventListener
(or attachEvent
on IE8 and earlier) so you can have multiple handlers for an event on an element.
Reset/remove CSS styles for element only
In my specific scenario i wanted to skip applying common styles to a specific part of the page, better illustrated like this:
<body class='common-styles'>
<div id='header'>Wants common styles</div>
<div id='container'>Does NOT want common styles</div>
<div id='footer'>Wants common styles</div>
</body>
After messing with CSS reset which didn't bring much success (mainly because of rules precedence and complex stylesheet hierarchy), brought up ubiquitous jQuery to the rescue, which did the job very quickly and reasonably dirty:
$(function() {
$('body').removeClass('common-styles');
$('#header,#footer').addClass('common-styles');
});
(Now tell how evil it is to use JS to deal with CSS :-) )
Getting user input
Use the following simple way to interactively
get user data by a prompt as Arguments on what you want.
Version : Python 3.X
name = input('Enter Your Name: ')
print('Hello ', name)
Detect home button press in android
Android Home Key handled by the framework layer you can't able to handle this in the application layer level. Because the home button action is already defined in the below level. But If you are developing your custom ROM, then It might be possible. Google restricted the HOME BUTTON override functions because of security reasons.
how to use python2.7 pip instead of default pip
There should be a binary called "pip2.7" installed at some location included within your $PATH variable.
You can find that out by typing
which pip2.7
This should print something like '/usr/local/bin/pip2.7' to your stdout. If it does not print anything like this, it is not installed. In that case, install it by running
$ wget https://bootstrap.pypa.io/get-pip.py
$ sudo python2.7 get-pip.py
Now, you should be all set, and
which pip2.7
should return the correct output.
sqlite3.OperationalError: unable to open database file
Run into the error on Windows, added assert os.path.exists, double checked the path, run the script as administrator, nothing helped.
Turns out if you add your folders to the Windows Defender's Ransomware Protection, you can no longer use other programs to write there unless you add these programs to the Controlled Folder Access' whitelist.
Solution - check if your folder has been added to the Windows Defender's Ransomware Protection and remove it for faster fix.
Erase the current printed console line
echo -e "hello\c" ;sleep 1 ; echo -e "\rbye "
What the above command will do :
It will print hello and the cursor will remain at "o" (using \c)
Then it will wait for 1 sec (sleep 1)
Then it will replace hello with bye.(using \r)
NOTE : Using ";", We can run multiple command in a single go.