How do I make a self extract and running installer
Okay I have got it working, hope this information is useful.
First of all I now realize that not only do self-extracting zip start extracting with doubleclick, but they require no extraction application to be installed on the users computer because the extractor code is in the archive itself. This means that you will get a different user experience depending on what you application you use to create the sfx
I went with WinRar as follows, this does not require you to create an sfx file, everything can be created via the gui:
- Select files, right click and select Add to Archive
- Use Browse.. to create the archive in the folder above
- Change Archive Format to Zip
- Enable Create SFX archive
- Select Advanced tab
- Select SFX Options
- Select Setup tab
- Enter setup.exe into the Run after Extraction field
- Select Modes tab
- Enable Unpack to temporary folder
- Select text and Icon tab
- Enter a more appropriate title for your task
- Select OK
- Select OK
The resultant exe unzips to a temporary folder and then starts the installer
How to sleep the thread in node.js without affecting other threads?
When working with async functions or observables provided by 3rd party libraries, for example Cloud firestore, I've found functions the waitFor
method shown below (TypeScript, but you get the idea...) to be helpful when you need to wait on some process to complete, but you don't want to have to embed callbacks within callbacks within callbacks nor risk an infinite loop.
This method is sort of similar to a while (!condition)
sleep loop, but
yields asynchronously and performs a test on the completion condition at regular intervals till true or timeout.
export const sleep = (ms: number) => {
return new Promise(resolve => setTimeout(resolve, ms))
}
/**
* Wait until the condition tested in a function returns true, or until
* a timeout is exceeded.
* @param interval The frenequency with which the boolean function contained in condition is called.
* @param timeout The maximum time to allow for booleanFunction to return true
* @param booleanFunction: A completion function to evaluate after each interval. waitFor will return true as soon as the completion function returns true.
*/
export const waitFor = async function (interval: number, timeout: number,
booleanFunction: Function): Promise<boolean> {
let elapsed = 1;
if (booleanFunction()) return true;
while (elapsed < timeout) {
elapsed += interval;
await sleep(interval);
if (booleanFunction()) {
return true;
}
}
return false;
}
The say you have a long running process on your backend you want to complete before some other task is undertaken. For example if you have a function that totals a list of accounts, but you want to refresh the accounts from the backend before you calculate, you can do something like this:
async recalcAccountTotals() : number {
this.accountService.refresh(); //start the async process.
if (this.accounts.dirty) {
let updateResult = await waitFor(100,2000,()=> {return !(this.accounts.dirty)})
}
if(!updateResult) {
console.error("Account refresh timed out, recalc aborted");
return NaN;
}
return ... //calculate the account total.
}
Convert string to variable name in python
You can use a Dictionary to keep track of the keys and values.
For instance...
dictOfStuff = {} ##Make a Dictionary
x = "Buffalo" ##OR it can equal the input of something, up to you.
dictOfStuff[x] = 4 ##Get the dict spot that has the same key ("name") as what X is equal to. In this case "Buffalo". and set it to 4. Or you can set it to what ever you like
print(dictOfStuff[x]) ##print out the value of the spot in the dict that same key ("name") as the dictionary.
A dictionary is very similar to a real life dictionary. You have a word and you have a definition. You can look up the word and get the definition. So in this case, you have the word "Buffalo" and it's definition is 4. It can work with any other word and definition. Just make sure you put them into the dictionary first.
How to change the status bar color in Android?
i used this code to change status bar to transparent
activity?.window?.setFlags(
WindowManager.LayoutParams.FLAG_LAYOUT_NO_LIMITS,
WindowManager.LayoutParams.FLAG_LAYOUT_NO_LIMITS
)
to change it to color in style used this code
i used in fragment in onDetach()
activity?.window?.clearFlags(WindowManager.LayoutParams.FLAG_LAYOUT_NO_LIMITS)
Understanding lambda in python and using it to pass multiple arguments
Why do you need to state both 'x' and 'y' before the ':'?
You could actually in some situations(when you have only one argument) do not put the x and y before ":".
>>> flist = []
>>> for i in range(3):
... flist.append(lambda : i)
but the i in the lambda will be bound by name, so,
>>> flist[0]()
2
>>> flist[2]()
2
>>>
different from what you may want.
How do I add a linker or compile flag in a CMake file?
You can also add linker flags to a specific target using the LINK_FLAGS
property:
set_property(TARGET ${target} APPEND_STRING PROPERTY LINK_FLAGS " ${flag}")
If you want to propagate this change to other targets, you can create a dummy target to link to.
How can I assign an ID to a view programmatically?
Android id
overview
An Android id
is an integer commonly used to identify views; this id
can be assigned via XML (when possible) and via code (programmatically.) The id
is most useful for getting references for XML-defined View
s generated by an Inflater
(such as by using setContentView
.)
Assign id
via XML
- Add an attribute of
android:id="@+id/
somename"
to your view.
- When your application is built, the
android:id
will be assigned a unique int
for use in code.
- Reference your
android:id
's int
value in code using "R.id.
somename" (effectively a constant.)
- this
int
can change from build to build so never copy an id from gen/
package.name/R.java
, just use "R.id.
somename".
- (Also, an
id
assigned to a Preference
in XML is not used when the Preference
generates its View
.)
Assign id
via code (programmatically)
- Manually set
id
s using someView.setId(
int);
- The
int
must be positive, but is otherwise arbitrary- it can be whatever you want (keep reading if this is frightful.)
- For example, if creating and numbering several views representing items, you could use their item number.
Uniqueness of id
s
XML
-assigned id
s will be unique.
- Code-assigned
id
s do not have to be unique
- Code-assigned
id
s can (theoretically) conflict with XML
-assigned id
s.
- These conflicting
id
s won't matter if queried correctly (keep reading).
When (and why) conflicting id
s don't matter
findViewById(int)
will iterate depth-first recursively through the view hierarchy from the View you specify and return the first View
it finds with a matching id
.
- As long as there are no code-assigned
id
s assigned before an XML-defined id
in the hierarchy, findViewById(R.id.somename)
will always return the XML-defined View so id
'd.
Dynamically Creating Views and Assigning ID
s
If you choose to keep references to your views around, be sure to instantiate them with getApplicationContext()
and be sure to set each reference to null in onDestroy
. Apparently leaking the Activity
(hanging onto it after is is destroyed) is wasteful.. :)
Reserve an XML android:id
for use in code
API 17 introduced View.generateViewId()
which generates a unique ID. (Thanks to take-chances-make-changes for pointing this out.)*
If your ViewGroup
cannot be defined via XML (or you don't want it to be) you can reserve the id via XML to ensure it remains unique:
Here, values/ids.xml defines a custom id
:
<?xml version="1.0" encoding="utf-8"?>
<resources>
<item name="reservedNamedId" type="id"/>
</resources>
Then once the ViewGroup or View has been created, you can attach the custom id
myViewGroup.setId(R.id.reservedNamedId);
Conflicting id
example
For clarity by way of obfuscating example, lets examine what happens when there is an id
conflict behind the scenes.
layout/mylayout.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<LinearLayout
android:id="@+id/placeholder"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:orientation="horizontal" >
</LinearLayout>
To simulate a conflict, lets say our latest build assigned R.id.placeholder
(@+id/placeholder
) an int
value of 12
..
Next, MyActivity.java defines some adds views programmatically (via code):
int placeholderId = R.id.placeholder; // placeholderId==12
// returns *placeholder* which has id==12:
ViewGroup placeholder = (ViewGroup)this.findViewById(placeholderId);
for (int i=0; i<20; i++){
TextView tv = new TextView(this.getApplicationContext());
// One new TextView will also be assigned an id==12:
tv.setId(i);
placeholder.addView(tv);
}
So placeholder
and one of our new TextView
s both have an id
of 12! But this isn't really a problem if we query placeholder's child views:
// Will return a generated TextView:
placeholder.findViewById(12);
// Whereas this will return the ViewGroup *placeholder*;
// as long as its R.id remains 12:
Activity.this.findViewById(12);
*Not so bad
Calculating Pearson correlation and significance in Python
An alternative can be a native scipy function from linregress which calculates:
slope : slope of the regression line
intercept : intercept of the regression line
r-value : correlation coefficient
p-value : two-sided p-value for a hypothesis test whose null hypothesis is that the slope is zero
stderr : Standard error of the estimate
And here is an example:
a = [15, 12, 8, 8, 7, 7, 7, 6, 5, 3]
b = [10, 25, 17, 11, 13, 17, 20, 13, 9, 15]
from scipy.stats import linregress
linregress(a, b)
will return you:
LinregressResult(slope=0.20833333333333337, intercept=13.375, rvalue=0.14499815458068521, pvalue=0.68940144811669501, stderr=0.50261704627083648)
How to export collection to CSV in MongoDB?
I could not get mongoexport to do this for me. I found that,to get an exhaustive list of all the fields, you need to loop through the entire collection once. Use this to generate the headers. Then loop through the collection again to populate these headers for each document.
I've written a script to do just this. Converting MongoDB docs to csv irrespective of schema differences between individual documents.
https://github.com/surya-shodan/mongoexportcsv
Best way to load module/class from lib folder in Rails 3?
In my case I was trying to simply load a file directly under the lib dir.
Within application.rb...
require '/lib/this_file.rb'
wasn't working, even in console and then when I tried
require './lib/this_file.rb'
and rails loads the file perfectly.
I'm still pretty noob and I'm not sure why this works but it works. If someone would like to explain it to me I'd appreciate it :D I hope this helps someone either way.
ActiveRecord OR query
in Rails 3, it should be
Model.where("column = ? or other_column = ?", value, other_value)
This also includes raw sql but I dont think there is a way in ActiveRecord to do OR operation. Your question is not a noob question.
Update ViewPager dynamically?
I know am late for the Party. I've fixed the problem by calling TabLayout#setupWithViewPager(myViewPager);
just after FragmentPagerAdapter#notifyDataSetChanged();
Calling a function on bootstrap modal open
will not work.. use $(window)
instead
For Showing
$(window).on('shown.bs.modal', function() {
$('#code').modal('show');
alert('shown');
});
For Hiding
$(window).on('hidden.bs.modal', function() {
$('#code').modal('hide');
alert('hidden');
});
npm global path prefix
Simple solution is ...
Just put below command :
sudo npm config get prefix
if it's not something like these /usr/local
, than you need to fix it using below command.
sudo npm config set prefix /usr/local
...
Now it's 100% working fine
How to call a method in MainActivity from another class?
But an error occurred which says java.lang.NullPointerException.
Thats because, you never initialized your MainActivity. you should initialize your object before you call its methods.
MainActivity mActivity = new MainActivity();//make sure that you pass the appropriate arguments if you have an args constructor
mActivity.startChronometer();
Forcing to download a file using PHP
If you are doing it with your application itself... I hope this code helps.
HTML
In href -- you have to add download_file.php along with your URL:
<a class="download" href="'/download_file.php?fileSource='+http://www.google.com/logo_small.png" target="_blank" title="YourTitle">
PHP
/* Here is the Download.php file to force download stuff */
<?php
$fullPath = $_GET['fileSource'];
if($fullPath) {
$fsize = filesize($fullPath);
$path_parts = pathinfo($fullPath);
$ext = strtolower($path_parts["extension"]);
switch ($ext) {
case "pdf":
header("Content-Disposition: attachment; filename=\"" . $path_parts["basename"]."\""); // Use 'attachment' to force a download
header("Content-type: application/pdf"); // Add here more headers for diff. extensions
break;
default;
header("Content-type: application/octet-stream");
header("Content-Disposition: filename=\"" . $path_parts["basename"]."\"");
}
if($fsize) { // Checking if file size exist
header("Content-length: $fsize");
}
readfile($fullPath);
exit;
}
?>
Setting a spinner onClickListener() in Android
Whenever you have to perform some action on the click of the Spinner in Android, use the following method.
mspUserState.setOnTouchListener(new OnTouchListener() {
@Override
public boolean onTouch(View v, MotionEvent event) {
if (event.getAction() == MotionEvent.ACTION_UP) {
doWhatIsRequired();
}
return false;
}
});
One thing to keep in mind is always to return False while using the above method. If you will return True then the dropdown items of the spinner will not be displayed on clicking the Spinner.
Pure CSS scroll animation
Use anchor links and the scroll-behavior
property (MDN reference) for the scrolling container:
scroll-behavior: smooth;
Browser support: Firefox 36+, Chrome 61+ (therefore also Edge 79+) and Opera 48+.
Intenet Explorer, non-Chromium Edge and (so far) Safari do not support scroll-behavior
and simply "jump" to the link target.
Example usage:
<head>
<style type="text/css">
html {
scroll-behavior: smooth;
}
</style>
</head>
<body id="body">
<a href="#foo">Go to foo!</a>
<!-- Some content -->
<div id="foo">That's foo.</div>
<a href="#body">Back to top</a>
</body>
Here's a Fiddle.
And here's also a Fiddle with both horizontal and vertical scrolling.
Eclipse java debugging: source not found
I've had a related issue in connection with Glassfish server debugging in Eclipse.
This was brought about by loading the source code from a different repository (changing from SVN to GitHub). In the process, the wrong compiled classes were used by the Glassfish server and hence, the source and run time would be out of sync with break points appearing on empty lines.
To solve this, rename or delete the top folder of the classes directory and Glassfish will recreate the whole class directory tree including updating the class files with the correctly compiled version.
The classes directory is located in: /workspace/glassfish3122eclipsedefaultdomain/eclipseApps/< your Web Application>/WEB-INF/classes
How do you split and unsplit a window/view in Eclipse IDE?
This is possible with the menu items Window>Editor>Toggle Split Editor.
Current shortcut for splitting is:
Azerty keyboard:
- Ctrl + _ for split horizontally, and
- Ctrl + { for split vertically.
Qwerty US keyboard:
- Ctrl + Shift + - (accessing _) for split horizontally, and
- Ctrl + Shift + [ (accessing {) for split vertically.
MacOS - Qwerty US keyboard:
- ⌘ + Shift + - (accessing _) for split horizontally, and
- ⌘ + Shift + [ (accessing {) for split vertically.
On any other keyboard if a required key is unavailable (like { on a german Qwertz keyboard), the following generic approach may work:
- Alt + ASCII code + Ctrl then release Alt
Example: ASCII for '{' = 123, so press 'Alt', '1', '2', '3', 'Ctrl' and release 'Alt', effectively typing '{' while 'Ctrl' is pressed, to split vertically.
Example of vertical split:
PS:
- The menu items Window>Editor>Toggle Split Editor were added with Eclipse Luna 4.4 M4, as mentioned by Lars Vogel in "Split editor implemented in Eclipse M4 Luna"
- The split editor is one of the oldest and most upvoted Eclipse bug! Bug 8009
- The split editor functionality has been developed in Bug 378298, and will be available as of Eclipse Luna M4. The Note & Newsworthy of Eclipse Luna M4 will contain the announcement.
How to assign bean's property an Enum value in Spring config file?
Use the value child element instead of the value attribute and specify the Enum class name:
<property name="residence">
<value type="SocialSecurity$Residence">ALIEN</value>
</property>
The advantage of this approach over just writing value="ALIEN"
is that it also works if Spring can't infer the actual type of the enum from the property (e.g. the property's declared type is an interface).Adapted from araqnid's comment.
Is there an addHeaderView equivalent for RecyclerView?
HeaderView depends on the LayoutManager. None of the default LayoutManagers support this and probably wont. HeaderView in ListView creates a lot of complexity without any significant benefit.
I would suggest creating a base adapter class that adds items for Headers if provided. Don't forget to override notify* methods to offset them properly depending on whether header is present or not.
UTF-8 text is garbled when form is posted as multipart/form-data
I had the same problem and it turned out that in addition to specifying the encoding in the Filter
request.setCharacterEncoding("UTF-8");
response.setCharacterEncoding("UTF-8");
it is necessary to add "acceptcharset" to the form
<form method="post" enctype="multipart/form-data" acceptcharset="UTF-8" >
and run the JVM with
-Dfile.encoding=UTF-8
The HTML meta tag is not necessary if you send it in the HTTP header using response.setCharacterEncoding().
Add support library to Android Studio project
Android no longer downloading the libraries from the SDK manager, it has to be accessed through Google's Maven repository.
You will have to do something similar to this in your build.gradle file:
allprojects {
repositories {
jcenter()
maven {
url "https://maven.google.com"
}
}
}
dependencies {
...
compile "com.android.support:support-core-utils:27.0.2"
}
Find more details about the setting up process here and about the different support library revisions here.
Coarse-grained vs fine-grained
Coarse-grained granularity does not always mean bigger components, if you go by literally meaning of the word coarse, it means harsh, or not appropriate. e.g. In software projects management, if you breakdown a small system into few components, which are equal in size, but varies in complexities and features, this could lead to a coarse-grained granularity. In reverse, for a fine-grained breakdown, you would divide the components based on their cohesiveness of the functionalities each component is providing.
Create a asmx web service in C# using visual studio 2013
Check your namespaces. I had and issue with that. I found that out by adding another web service to the project to dup it like you did yours and noticed the namespace was different. I had renamed it at the beginning of the project and it looks like its persisted.
Cannot find "Package Explorer" view in Eclipse
For Eclipse version 4.3.0.v20130605-2000. You can use the Java (default) perspective. In this perspective, it provides the Package Explorer view.
To use the Java (default) perspective:
Window -> Open Perspective -> Other... -> Java (default) -> Ok
If you already use the Java (default) perspective but accidentally close the Package Explorer view, you can open it by;
Window -> Show View -> Package Explorer (Alt+Shift+Q,P)
If the Package Explorer still doesn't appear in the Java (default) perspective, I suggest you to right-click on the Java (default) perspective button that is located in the top-right of the Eclipse IDE and then select Reset. The Java (default) perspective will show the Package Explorer view, Code pane, Outline view, Problems, JavaDoc and Declaration View.
C - casting int to char and append char to char
You can use itoa function to convert the integer to a string.
You can use strcat function to append characters in a string at the end of another string.
If you want to convert a integer to a character, just do the following -
int a = 65;
char c = (char) a;
Note that since characters are smaller in size than integer, this casting may cause a loss of data. It's better to declare the character variable as unsigned
in this case (though you may still lose data).
To do a light reading about type conversion, go here.
If you are still having trouble, comment on this answer.
Edit
Go here for a more suitable example of joining characters.
Also some more useful link is given below -
- http://www.cplusplus.com/reference/clibrary/cstring/strncat/
- http://www.cplusplus.com/reference/clibrary/cstring/strcat/
Second Edit
char msg[200];
int msgLength;
char rankString[200];
........... // Your message has arrived
msgLength = strlen(msg);
itoa(rank, rankString, 10); // I have assumed rank is the integer variable containing the rank id
strncat( msg, rankString, (200 - msgLength) ); // msg now contains previous msg + id
// You may loose some portion of id if message length + id string length is greater than 200
Third Edit
Go to this link. Here you will find an implementation of itoa
. Use that instead.
Bootstrap 3.0 - Fluid Grid that includes Fixed Column Sizes
Why not just set the left two columns to a fixed with in your own css and then make a new grid layout of the full 12 columns for the rest of the content?
<div class="row">
<div class="fixed-1">Left 1</div>
<div class="fixed-2">Left 2</div>
<div class="row">
<div class="col-md-1"></div>
<div class="col-md-11"></div>
</div>
</div>
open read and close a file in 1 line of code
Python Standard Library Pathlib module does what you looking for:
Path('pagehead.section.htm').read_text()
Don't forget to import Path:
jsk@dev1:~$ python3
Python 3.5.2 (default, Sep 10 2016, 08:21:44)
[GCC 5.4.0 20160609] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> from pathlib import Path
>>> (Path("/etc") / "hostname").read_text()
'dev1.example\n'
On Python 27 install backported pathlib
or pathlib2
Efficient way of having a function only execute once in a loop
There are many ways to do what you want; however, do note that it is quite possible that —as described in the question— you don't have to call the function inside the loop.
If you insist in having the function call inside the loop, you can also do:
needs_to_run= expensive_function
while 1:
…
if needs_to_run: needs_to_run(); needs_to_run= None
…
Activate a virtualenv with a Python script
The simplest solution to run your script under virtualenv's interpreter is to replace the default shebang line with path to your virtualenv's interpreter like so at the beginning of the script:
#!/path/to/project/venv/bin/python
Make the script executable:
chmod u+x script.py
Run the script:
./script.py
Voila!
HTTP could not register URL http://+:8000/HelloWCF/. Your process does not have access rights to this namespace
Your sample code won't work as shown because you forgot to include a Console.ReadLine()
before the serviceHost.Close()
line. That means the host is opened and then immediately closed.
Other than that, it seems you have a permission problem on your machine. Ensure you are logged-in as an administrator account on your machine. If you are an administrator then it may be that you don't have the World Wide Web Publishing Service (W3SVC) running to handle HTTP requests.
YAML equivalent of array of objects in JSON
TL;DR
You want this:
AAPL:
- shares: -75.088
date: 11/27/2015
- shares: 75.088
date: 11/26/2015
Mappings
The YAML equivalent of a JSON object is a mapping, which looks like these:
# flow style
{ foo: 1, bar: 2 }
# block style
foo: 1
bar: 2
Note that the first characters of the keys in a block mapping must be in the same column. To demonstrate:
# OK
foo: 1
bar: 2
# Parse error
foo: 1
bar: 2
Sequences
The equivalent of a JSON array in YAML is a sequence, which looks like either of these (which are equivalent):
# flow style
[ foo bar, baz ]
# block style
- foo bar
- baz
In a block sequence the -
s must be in the same column.
JSON to YAML
Let's turn your JSON into YAML. Here's your JSON:
{"AAPL": [
{
"shares": -75.088,
"date": "11/27/2015"
},
{
"shares": 75.088,
"date": "11/26/2015"
},
]}
As a point of trivia, YAML is a superset of JSON, so the above is already valid YAML—but let's actually use YAML's features to make this prettier.
Starting from the inside out, we have objects that look like this:
{
"shares": -75.088,
"date": "11/27/2015"
}
The equivalent YAML mapping is:
shares: -75.088
date: 11/27/2015
We have two of these in an array (sequence):
- shares: -75.088
date: 11/27/2015
- shares: 75.088
date: 11/26/2015
Note how the -
s line up and the first characters of the mapping keys line up.
Finally, this sequence is itself a value in a mapping with the key AAPL
:
AAPL:
- shares: -75.088
date: 11/27/2015
- shares: 75.088
date: 11/26/2015
Parsing this and converting it back to JSON yields the expected result:
{
"AAPL": [
{
"date": "11/27/2015",
"shares": -75.088
},
{
"date": "11/26/2015",
"shares": 75.088
}
]
}
You can see it (and edit it interactively) here.
How to change background color in android app
This method worked for me:
RelativeLayout relativeLayout = (RelativeLayout) findViewById(R.layout.rootLayout);
relativeLayout.setBackgroundColor(getResources().getColor(R.color.bg_color_2));
Set id in layout xml
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="@+id/rootLayout"
android:background="@color/background_color"
Add color values/color.xml
<color name="bg_color_2">#ffeef7f0</color>
Enable 'xp_cmdshell' SQL Server
While the accepted answer will work most of the times, I have encountered (still do not know why) some cases that is does not. A slight modification of the query by using the WITH OVERRIDE
in RECONFIGURE
gives the solution
Use Master
GO
EXEC master.dbo.sp_configure 'show advanced options', 1
RECONFIGURE WITH OVERRIDE
GO
EXEC master.dbo.sp_configure 'xp_cmdshell', 1
RECONFIGURE WITH OVERRIDE
GO
The expected output is
Configuration option 'show advanced options' changed from 0 to 1. Run the RECONFIGURE statement to install.
Configuration option 'xp_cmdshell' changed from 0 to 1. Run the RECONFIGURE statement to install.
VueJs get url query
I think you can simple call like this, this will give you result value.
this.$route.query.page
Look image $route is object in Vue Instance and you can access with this keyword and next you can select object properties like above one :
Have a look Vue-router document for selecting queries value :
Vue Router Object
Where does the .gitignore file belong?
In the simple case, a repository might have a single .gitignore
file in its root directory, which applies recursively to the entire repository. However, it is also possible to have additional .gitignore
files in subdirectories. The rules in these nested .gitignore
files apply only to the files under the directory where they are located. The Linux kernel source repository has 206 .gitignore
files.
-- this is what i read from progit.pdf
(version 2), P32
Efficient evaluation of a function at every cell of a NumPy array
I believe I have found a better solution. The idea to change the function to python universal function (see documentation), which can exercise parallel computation under the hood.
One can write his own customised ufunc
in C, which surely is more efficient, or by invoking np.frompyfunc
, which is built-in factory method. After testing, this is more efficient than np.vectorize
:
f = lambda x, y: x * y
f_arr = np.frompyfunc(f, 2, 1)
vf = np.vectorize(f)
arr = np.linspace(0, 1, 10000)
%timeit f_arr(arr, arr) # 307ms
%timeit f_arr(arr, arr) # 450ms
I have also tested larger samples, and the improvement is proportional. For comparison of performances of other methods, see this post
Python: Writing to and Reading from serial port
ser.read(64)
should be ser.read(size=64)
; ser.read uses keyword arguments, not positional.
Also, you're reading from the port twice; what you probably want to do is this:
i=0
for modem in PortList:
for port in modem:
try:
ser = serial.Serial(port, 9600, timeout=1)
ser.close()
ser.open()
ser.write("ati")
time.sleep(3)
read_val = ser.read(size=64)
print read_val
if read_val is not '':
print port
except serial.SerialException:
continue
i+=1
Select a Dictionary<T1, T2> with LINQ
A more explicit option is to project collection to an IEnumerable of KeyValuePair
and then convert it to a Dictionary.
Dictionary<int, string> dictionary = objects
.Select(x=> new KeyValuePair<int, string>(x.Id, x.Name))
.ToDictionary(x=>x.Key, x=>x.Value);
How can I completely uninstall nodejs, npm and node in Ubuntu
It is better to remove NodeJS and its modules manually because installation leaves a lot of files, links and modules behind and later this creates problems when we reconfigure another version of NodeJS and its modules.
To remove the files, run the following commands:
sudo rm -rf /usr/local/bin/npm
sudo rm -rf /usr/local/share/man/man1/node*
sudo rm -rf /usr/local/lib/dtrace/node.d
rm -rf ~/.npm
rm -rf ~/.node-gyp
sudo rm -rf /opt/local/bin/node
sudo rm -rf /opt/local/include/node
sudo rm -rf /opt/local/lib/node_modules
sudo rm -rf /usr/local/lib/node*
sudo rm -rf /usr/local/include/node*
sudo rm -rf /usr/local/bin/node*
I have posted a step by step guide with commands on my blog: AMCOS IT Support For Windows and Linux: To completely uninstall node js from Ubuntu.
Flask example with POST
Before actually answering your question:
Parameters in a URL (e.g. key=listOfUsers/user1
) are GET
parameters and you shouldn't be using them for POST
requests. A quick explanation of the difference between GET and POST can be found here.
In your case, to make use of REST principles, you should probably have:
http://ip:5000/users
http://ip:5000/users/<user_id>
Then, on each URL, you can define the behaviour of different HTTP methods (GET
, POST
, PUT
, DELETE
). For example, on /users/<user_id>
, you want the following:
GET /users/<user_id> - return the information for <user_id>
POST /users/<user_id> - modify/update the information for <user_id> by providing the data
PUT - I will omit this for now as it is similar enough to `POST` at this level of depth
DELETE /users/<user_id> - delete user with ID <user_id>
So, in your example, you want do a POST
to /users/user_1
with the POST data being "John"
. Then the XPath expression or whatever other way you want to access your data should be hidden from the user and not tightly couple to the URL. This way, if you decide to change the way you store and access data, instead of all your URL's changing, you will simply have to change the code on the server-side.
Now, the answer to your question:
Below is a basic semi-pseudocode of how you can achieve what I mentioned above:
from flask import Flask
from flask import request
app = Flask(__name__)
@app.route('/users/<user_id>', methods = ['GET', 'POST', 'DELETE'])
def user(user_id):
if request.method == 'GET':
"""return the information for <user_id>"""
.
.
.
if request.method == 'POST':
"""modify/update the information for <user_id>"""
# you can use <user_id>, which is a str but could
# changed to be int or whatever you want, along
# with your lxml knowledge to make the required
# changes
data = request.form # a multidict containing POST data
.
.
.
if request.method == 'DELETE':
"""delete user with ID <user_id>"""
.
.
.
else:
# POST Error 405 Method Not Allowed
.
.
.
There are a lot of other things to consider like the POST
request content-type but I think what I've said so far should be a reasonable starting point. I know I haven't directly answered the exact question you were asking but I hope this helps you. I will make some edits/additions later as well.
Thanks and I hope this is helpful. Please do let me know if I have gotten something wrong.
Setting font on NSAttributedString on UITextView disregards line spacing
//For proper line spacing
NSString *text1 = @"Hello";
NSString *text2 = @"\nWorld";
UIFont *text1Font = [UIFont fontWithName:@"HelveticaNeue-Medium" size:10];
NSMutableAttributedString *attributedString1 =
[[NSMutableAttributedString alloc] initWithString:text1 attributes:@{ NSFontAttributeName : text1Font }];
NSMutableParagraphStyle *paragraphStyle1 = [[NSMutableParagraphStyle alloc] init];
[paragraphStyle1 setAlignment:NSTextAlignmentCenter];
[paragraphStyle1 setLineSpacing:4];
[attributedString1 addAttribute:NSParagraphStyleAttributeName value:paragraphStyle1 range:NSMakeRange(0, [attributedString1 length])];
UIFont *text2Font = [UIFont fontWithName:@"HelveticaNeue-Medium" size:16];
NSMutableAttributedString *attributedString2 =
[[NSMutableAttributedString alloc] initWithString:text2 attributes:@{NSFontAttributeName : text2Font }];
NSMutableParagraphStyle *paragraphStyle2 = [[NSMutableParagraphStyle alloc] init];
[paragraphStyle2 setLineSpacing:4];
[paragraphStyle2 setAlignment:NSTextAlignmentCenter];
[attributedString2 addAttribute:NSParagraphStyleAttributeName value:paragraphStyle2 range:NSMakeRange(0, [attributedString2 length])];
[attributedString1 appendAttributedString:attributedString2];
sql query to get earliest date
Try
select * from dataset
where id = 2
order by date limit 1
Been a while since I did sql, so this might need some tweaking.
first-child and last-child with IE8
Since :last-child
is a CSS3 pseudo-class, it is not supported in IE8. I believe :first-child
is supported, as it's defined in the CSS2.1 specification.
One possible solution is to simply give the last child a class name and style that class.
Another would be to use JavaScript. jQuery makes this particularly easy as it provides a :last-child
pseudo-class which should work in IE8. Unfortunately, that could result in a flash of unstyled content while the DOM loads.
How to switch to the new browser window, which opens after click on the button?
So the problem with a lot of these solutions is you're assuming the window appears instantly (nothing happens instantly, and things happen significantly less instantly in IE). Also you're assuming that there will only be one window prior to clicking the element, which is not always the case. Also IE will not return the window handles in a predictable order. So I would do the following.
public String clickAndSwitchWindow(WebElement elementToClick, Duration
timeToWaitForWindowToAppear) {
Set<String> priorHandles = _driver.getWindowHandles();
elementToClick.click();
try {
new WebDriverWait(_driver,
timeToWaitForWindowToAppear.getSeconds()).until(
d -> {
Set<String> newHandles = d.getWindowHandles();
if (newHandles.size() > priorHandles.size()) {
for (String newHandle : newHandles) {
if (!priorHandles.contains(newHandle)) {
d.switchTo().window(newHandle);
return true;
}
}
return false;
} else {
return false;
}
});
} catch (Exception e) {
Logging.log_AndFail("Encountered error while switching to new window after clicking element " + elementToClick.toString()
+ " seeing error: \n" + e.getMessage());
}
return _driver.getWindowHandle();
}
How can I scroll a web page using selenium webdriver in python?
scroll loading pages. Example: medium, quora,etc
last_height = driver.execute_script("return document.body.scrollHeight")
while True:
driver.execute_script("window.scrollTo(0, document.body.scrollHeight-1000);")
# Wait to load the page.
driver.implicitly_wait(30) # seconds
new_height = driver.execute_script("return document.body.scrollHeight")
if new_height == last_height:
break
last_height = new_height
# sleep for 30s
driver.implicitly_wait(30) # seconds
driver.quit()
SQL Developer is returning only the date, not the time. How do I fix this?
This will get you the hours, minutes and second. hey presto.
select
to_char(CREATION_TIME,'RRRR') year,
to_char(CREATION_TIME,'MM') MONTH,
to_char(CREATION_TIME,'DD') DAY,
to_char(CREATION_TIME,'HH:MM:SS') TIME,
sum(bytes) Bytes
from
v$datafile
group by
to_char(CREATION_TIME,'RRRR'),
to_char(CREATION_TIME,'MM'),
to_char(CREATION_TIME,'DD'),
to_char(CREATION_TIME,'HH:MM:SS')
ORDER BY 1, 2;
How to call a VbScript from a Batch File without opening an additional command prompt
If you want to fix vbs associations type
regsvr32 vbscript.dll
regsvr32 jscript.dll
regsvr32 wshext.dll
regsvr32 wshom.ocx
regsvr32 wshcon.dll
regsvr32 scrrun.dll
Also if you can't use vbs due to management then convert your script to a vb.net program which is designed to be easy, is easy, and takes 5 minutes.
Big difference is functions and subs are both called using brackets rather than just functions.
So the compilers are installed on all computers with .NET installed.
See this article here on how to make a .NET exe. Note the sample is for a scripting host. You can't use this, you have to put your vbs code in as .NET code.
How can I convert a VBScript to an executable (EXE) file?
Starting ssh-agent on Windows 10 fails: "unable to start ssh-agent service, error :1058"
Yeah, as others have suggested, this error seems to mean that ssh-agent is installed but its service (on windows) hasn't been started.
You can check this by running in Windows PowerShell:
> Get-Service ssh-agent
And then check the output of status is not running.
Status Name DisplayName
------ ---- -----------
Stopped ssh-agent OpenSSH Authentication Agent
Then check that the service has been disabled by running
> Get-Service ssh-agent | Select StartType
StartType
---------
Disabled
I suggest setting the service to start manually. This means that as soon as you run ssh-agent, it'll start the service. You can do this through the Services GUI or you can run the command in admin mode:
> Get-Service -Name ssh-agent | Set-Service -StartupType Manual
Alternatively, you can set it through the GUI if you prefer.
Execute a terminal command from a Cocoa app
fork, exec, and wait should work, if you're not really looking for a Objective-C specific way. fork
creates a copy of the currently running program, exec
replaces the currently running program with a new one, and wait
waits for the subprocess to exit. For example (without any error checking):
#include <stdlib.h>
#include <unistd.h>
pid_t p = fork();
if (p == 0) {
/* fork returns 0 in the child process. */
execl("/other/program/to/run", "/other/program/to/run", "foo", NULL);
} else {
/* fork returns the child's PID in the parent. */
int status;
wait(&status);
/* The child has exited, and status contains the way it exited. */
}
/* The child has run and exited by the time execution gets to here. */
There's also system, which runs the command as if you typed it from the shell's command line. It's simpler, but you have less control over the situation.
I'm assuming you're working on a Mac application, so the links are to Apple's documentation for these functions, but they're all POSIX
, so you should be to use them on any POSIX-compliant system.
How to secure MongoDB with username and password
This answer is for Mongo 3.2.1
Reference
Terminal 1:
$ mongod --auth
Terminal 2:
db.createUser({user:"admin_name", pwd:"1234",roles:["readWrite","dbAdmin"]})
if you want to add without roles (optional):
db.createUser({user:"admin_name", pwd:"1234", roles:[]})
to check if authenticated or not:
db.auth("admin_name", "1234")
it should give you:
1
else :
Error: Authentication failed.
0
Why cannot cast Integer to String in java?
No, Integer
and String
are different types. To convert an integer to string use: String.valueOf(integer)
, or Integer.toString(integer)
for primitive, or Integer.toString()
for the object.
Why am I getting this error Premature end of file?
When you do this,
while((inputLine = buff_read.readLine())!= null){
System.out.println(inputLine);
}
You consume everything in instream, so instream is empty. Now when try to do this,
Document doc = builder.parse(instream);
The parsing will fail, because you have passed it an empty stream.
window.open with target "_blank" in Chrome
"_blank" is not guaranteed to be a new tab or window. It's implemented differently per-browser.
You can, however, put anything into target. I usually just say "_tab", and every browser I know of just opens it in a new tab.
Be aware that it means it's a named target, so if you try to open 2 URLs, they will use the same tab.
Curl: Fix CURL (51) SSL error: no alternative certificate subject name matches
it might save some time to somebody.
If you use GuzzleHttp and you face with this error message cURL error 60: SSL: no alternative certificate subject name matches target host name and you are fine with the 'insecure' solution (not recommended on production) then you have to add
\GuzzleHttp\RequestOptions::VERIFY => false
to the client configuration:
$this->client = new \GuzzleHttp\Client([
'base_uri' => 'someAccessPoint',
\GuzzleHttp\RequestOptions::HEADERS => [
'User-Agent' => 'some-special-agent',
],
'defaults' => [
\GuzzleHttp\RequestOptions::CONNECT_TIMEOUT => 5,
\GuzzleHttp\RequestOptions::ALLOW_REDIRECTS => true,
],
\GuzzleHttp\RequestOptions::VERIFY => false,
]);
which sets CURLOPT_SSL_VERIFYHOST
to 0 and CURLOPT_SSL_VERIFYPEER
to false in the CurlFactory::applyHandlerOptions()
method
$conf[CURLOPT_SSL_VERIFYHOST] = 0;
$conf[CURLOPT_SSL_VERIFYPEER] = false;
From the GuzzleHttp documentation
verify
Describes the SSL certificate verification behavior of a request.
- Set to true to enable SSL certificate verification and use the default CA bundle > provided by operating system.
- Set to false to disable certificate verification (this is insecure!).
- Set to a string to provide the path to a CA bundle to enable verification using a custom certificate.
How can I comment a single line in XML?
As others have said, there is no way to do a single line comment legally in XML that comments out multiple lines, but, there are ways to make commenting out segments of XML easier.
Looking at the example below, if you add '>' to line one, the XmlTag will be uncommented. Remove the '>' and it's commented out again. This is the simplest way that I've seen to quickly comment/uncomment XML without breaking things.
<!-- --
<XmlTag variable="0" />
<!-- -->
The added benefit is that you only manipulate the top comment, and the bottom comment can just sit there forever. This breaks compatibility with SGML and some XML parsers will barf on it. So long as this isn't a permanent fixture in your XML, and your parsers accept it, it's not really a problem.
Stack Overflow's and Notepad++'s syntax highlighter treat it like a multi-line comment, C++'s Boost library treats it as a multi-line comment, and the only parser I've found so far that breaks is the one in .NET, specifically C#. So, be sure to first test that your tools, IDE, libraries, language, etc. accept it before using it.
If you care about SGML compatibility, simply use this instead:
<!-- -
<XmlTag variable="0" />
<!- -->
Add '->' to the top comment and a '-' to the bottom comment. The downside is having to edit the bottom comment each time, which would probably make it easier to just type in <!--
at the top and -->
at the bottom each time.
I also want to mention that other commenters recommend using an XML editor that allows you to right-click and comment/uncomment blocks of XML, which is probably preferable over fancy find/replace tricks (it would also make for a good answer in itself, but I've never used such tools. I just want to make sure the information isn't lost over time). I've personally never had to deal with XML enough to justify having an editor fancier than Notepad++, so this is totally up to you.
Simple insecure two-way data "obfuscation"?
Other answers here work fine, but AES is a more secure and up-to-date encryption algorithm. This is a class that I obtained a few years ago to perform AES encryption that I have modified over time to be more friendly for web applications (e,g. I've built Encrypt/Decrypt methods that work with URL-friendly string). It also has the methods that work with byte arrays.
NOTE: you should use different values in the Key (32 bytes) and Vector (16 bytes) arrays! You wouldn't want someone to figure out your keys by just assuming that you used this code as-is! All you have to do is change some of the numbers (must be <= 255) in the Key and Vector arrays (I left one invalid value in the Vector array to make sure you do this...). You can use https://www.random.org/bytes/ to generate a new set easily:
Using it is easy: just instantiate the class and then call (usually) EncryptToString(string StringToEncrypt) and DecryptString(string StringToDecrypt) as methods. It couldn't be any easier (or more secure) once you have this class in place.
using System;
using System.Data;
using System.Security.Cryptography;
using System.IO;
public class SimpleAES
{
// Change these keys
private byte[] Key = __Replace_Me__({ 123, 217, 19, 11, 24, 26, 85, 45, 114, 184, 27, 162, 37, 112, 222, 209, 241, 24, 175, 144, 173, 53, 196, 29, 24, 26, 17, 218, 131, 236, 53, 209 });
// a hardcoded IV should not be used for production AES-CBC code
// IVs should be unpredictable per ciphertext
private byte[] Vector = __Replace_Me__({ 146, 64, 191, 111, 23, 3, 113, 119, 231, 121, 2521, 112, 79, 32, 114, 156 });
private ICryptoTransform EncryptorTransform, DecryptorTransform;
private System.Text.UTF8Encoding UTFEncoder;
public SimpleAES()
{
//This is our encryption method
RijndaelManaged rm = new RijndaelManaged();
//Create an encryptor and a decryptor using our encryption method, key, and vector.
EncryptorTransform = rm.CreateEncryptor(this.Key, this.Vector);
DecryptorTransform = rm.CreateDecryptor(this.Key, this.Vector);
//Used to translate bytes to text and vice versa
UTFEncoder = new System.Text.UTF8Encoding();
}
/// -------------- Two Utility Methods (not used but may be useful) -----------
/// Generates an encryption key.
static public byte[] GenerateEncryptionKey()
{
//Generate a Key.
RijndaelManaged rm = new RijndaelManaged();
rm.GenerateKey();
return rm.Key;
}
/// Generates a unique encryption vector
static public byte[] GenerateEncryptionVector()
{
//Generate a Vector
RijndaelManaged rm = new RijndaelManaged();
rm.GenerateIV();
return rm.IV;
}
/// ----------- The commonly used methods ------------------------------
/// Encrypt some text and return a string suitable for passing in a URL.
public string EncryptToString(string TextValue)
{
return ByteArrToString(Encrypt(TextValue));
}
/// Encrypt some text and return an encrypted byte array.
public byte[] Encrypt(string TextValue)
{
//Translates our text value into a byte array.
Byte[] bytes = UTFEncoder.GetBytes(TextValue);
//Used to stream the data in and out of the CryptoStream.
MemoryStream memoryStream = new MemoryStream();
/*
* We will have to write the unencrypted bytes to the stream,
* then read the encrypted result back from the stream.
*/
#region Write the decrypted value to the encryption stream
CryptoStream cs = new CryptoStream(memoryStream, EncryptorTransform, CryptoStreamMode.Write);
cs.Write(bytes, 0, bytes.Length);
cs.FlushFinalBlock();
#endregion
#region Read encrypted value back out of the stream
memoryStream.Position = 0;
byte[] encrypted = new byte[memoryStream.Length];
memoryStream.Read(encrypted, 0, encrypted.Length);
#endregion
//Clean up.
cs.Close();
memoryStream.Close();
return encrypted;
}
/// The other side: Decryption methods
public string DecryptString(string EncryptedString)
{
return Decrypt(StrToByteArray(EncryptedString));
}
/// Decryption when working with byte arrays.
public string Decrypt(byte[] EncryptedValue)
{
#region Write the encrypted value to the decryption stream
MemoryStream encryptedStream = new MemoryStream();
CryptoStream decryptStream = new CryptoStream(encryptedStream, DecryptorTransform, CryptoStreamMode.Write);
decryptStream.Write(EncryptedValue, 0, EncryptedValue.Length);
decryptStream.FlushFinalBlock();
#endregion
#region Read the decrypted value from the stream.
encryptedStream.Position = 0;
Byte[] decryptedBytes = new Byte[encryptedStream.Length];
encryptedStream.Read(decryptedBytes, 0, decryptedBytes.Length);
encryptedStream.Close();
#endregion
return UTFEncoder.GetString(decryptedBytes);
}
/// Convert a string to a byte array. NOTE: Normally we'd create a Byte Array from a string using an ASCII encoding (like so).
// System.Text.ASCIIEncoding encoding = new System.Text.ASCIIEncoding();
// return encoding.GetBytes(str);
// However, this results in character values that cannot be passed in a URL. So, instead, I just
// lay out all of the byte values in a long string of numbers (three per - must pad numbers less than 100).
public byte[] StrToByteArray(string str)
{
if (str.Length == 0)
throw new Exception("Invalid string value in StrToByteArray");
byte val;
byte[] byteArr = new byte[str.Length / 3];
int i = 0;
int j = 0;
do
{
val = byte.Parse(str.Substring(i, 3));
byteArr[j++] = val;
i += 3;
}
while (i < str.Length);
return byteArr;
}
// Same comment as above. Normally the conversion would use an ASCII encoding in the other direction:
// System.Text.ASCIIEncoding enc = new System.Text.ASCIIEncoding();
// return enc.GetString(byteArr);
public string ByteArrToString(byte[] byteArr)
{
byte val;
string tempStr = "";
for (int i = 0; i <= byteArr.GetUpperBound(0); i++)
{
val = byteArr[i];
if (val < (byte)10)
tempStr += "00" + val.ToString();
else if (val < (byte)100)
tempStr += "0" + val.ToString();
else
tempStr += val.ToString();
}
return tempStr;
}
}
The request was aborted: Could not create SSL/TLS secure channel
The approach with setting
ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12
Seems to be okay, because Tls1.2 is latest version of secure protocol. But I decided to look deeper and answer do we really need to hardcode it.
Specs: Windows Server 2012R2 x64.
From the internet there is told that .NetFramework 4.6+ must use Tls1.2 by default. But when I updated my project to 4.6 nothing happened.
I have found some info that tells I need manually do some changes to enable Tls1.2 by default
https://support.microsoft.com/en-in/help/3140245/update-to-enable-tls-1-1-and-tls-1-2-as-default-secure-protocols-in-wi
But proposed windows update doesnt work for R2 version
But what helped me is adding 2 values to registry. You can use next PS script so they will be added automatically
Set-ItemProperty -Path 'HKLM:\SOFTWARE\Wow6432Node\Microsoft\.NetFramework\v4.0.30319' -Name 'SchUseStrongCrypto' -Value '1' -Type DWord
Set-ItemProperty -Path 'HKLM:\SOFTWARE\Microsoft\.NetFramework\v4.0.30319' -Name 'SchUseStrongCrypto' -Value '1' -Type DWord
That is kind of what I was looking for. But still I cant answer on question why NetFramework 4.6+ doesn't set this ...Protocol value automatically?
Add a prefix string to beginning of each line
Using ed:
ed infile <<'EOE'
,s/^/prefix/
wq
EOE
This substitutes, for each line (,
), the beginning of the line (^
) with prefix
. wq
saves and exits.
If the replacement string contains a slash, we can use a different delimiter for s
instead:
ed infile <<'EOE'
,s#^#/opt/workdir/#
wq
EOE
I've quoted the here-doc delimiter EOE
("end of ed") to prevent parameter expansion. In this example, it would work unquoted as well, but it's good practice to prevent surprises if you ever have a $
in your ed script.
How get data from material-ui TextField, DropDownMenu components?
use the accepted answer / this was the answer to another (already deleted) question
@karopastal
add a ref
attribute to your <TextField />
component and call getValue() on it, like this:
Component:
<TextField ref="myField" />
Using getValue:
this.refs.myField.getValue()
"Full screen" <iframe>
You can also use viewport-percentage lengths to achieve this:
5.1.2. Viewport-percentage lengths: the ‘vw’, ‘vh’, ‘vmin’, ‘vmax’ units
The viewport-percentage lengths are relative to the size of the initial containing block. When the height or width of the initial containing block is changed, they are scaled accordingly.
Where 100vh
represents the height of the viewport, and likewise 100vw
represents the width.
Example Here
_x000D_
_x000D_
body {_x000D_
margin: 0; /* Reset default margin */_x000D_
}_x000D_
iframe {_x000D_
display: block; /* iframes are inline by default */_x000D_
background: #000;_x000D_
border: none; /* Reset default border */_x000D_
height: 100vh; /* Viewport-relative units */_x000D_
width: 100vw;_x000D_
}
_x000D_
<iframe></iframe>
_x000D_
_x000D_
_x000D_
This is supported in most modern browsers - support can be found here.
How to execute VBA Access module?
Well it depends on how you want to call this code.
Are you calling it from a button click on a form, if so then on the properties for the button on form, go to the Event tab, then On Click item, select [Event Procedure]. This will open the VBA code window for that button. You would then call your Module.Routine and then this would trigger when you click the button.
Similar to this:
Private Sub Command1426_Click()
mdl_ExportMorning.ExportMorning
End Sub
This button click event calls the Module mdl_ExportMorning
and the Public Sub ExportMorning
.
Search text in fields in every table of a MySQL database
I am use HeidiSQL is a useful and reliable tool designed for web developers using the popular MySQL server.
In HeidiSQL you can push shift + ctrl + f and you can find text on the server in all tables. This option is very usefully.
LINQ to SQL using GROUP BY and COUNT(DISTINCT)
There isn't direct support for COUNT(DISTINCT {x}))
, but you can simulate it from an IGrouping<,>
(i.e. what group by
returns); I'm afraid I only "do" C#, so you'll have to translate to VB...
select new
{
Foo= grp.Key,
Bar= grp.Select(x => x.SomeField).Distinct().Count()
};
Here's a Northwind example:
using(var ctx = new DataClasses1DataContext())
{
ctx.Log = Console.Out; // log TSQL to console
var qry = from cust in ctx.Customers
where cust.CustomerID != ""
group cust by cust.Country
into grp
select new
{
Country = grp.Key,
Count = grp.Select(x => x.City).Distinct().Count()
};
foreach(var row in qry.OrderBy(x=>x.Country))
{
Console.WriteLine("{0}: {1}", row.Country, row.Count);
}
}
The TSQL isn't quite what we'd like, but it does the job:
SELECT [t1].[Country], (
SELECT COUNT(*)
FROM (
SELECT DISTINCT [t2].[City]
FROM [dbo].[Customers] AS [t2]
WHERE ((([t1].[Country] IS NULL) AND ([t2].[Country] IS NULL)) OR (([t1]
.[Country] IS NOT NULL) AND ([t2].[Country] IS NOT NULL) AND ([t1].[Country] = [
t2].[Country]))) AND ([t2].[CustomerID] <> @p0)
) AS [t3]
) AS [Count]
FROM (
SELECT [t0].[Country]
FROM [dbo].[Customers] AS [t0]
WHERE [t0].[CustomerID] <> @p0
GROUP BY [t0].[Country]
) AS [t1]
-- @p0: Input NVarChar (Size = 0; Prec = 0; Scale = 0) []
-- Context: SqlProvider(Sql2008) Model: AttributedMetaModel Build: 3.5.30729.1
The results, however, are correct- verifyable by running it manually:
const string sql = @"
SELECT c.Country, COUNT(DISTINCT c.City) AS [Count]
FROM Customers c
WHERE c.CustomerID != ''
GROUP BY c.Country
ORDER BY c.Country";
var qry2 = ctx.ExecuteQuery<QueryResult>(sql);
foreach(var row in qry2)
{
Console.WriteLine("{0}: {1}", row.Country, row.Count);
}
With definition:
class QueryResult
{
public string Country { get; set; }
public int Count { get; set; }
}
ASP.Net MVC: How to display a byte array image from model
One way is to add this to a new c# class or HtmlExtensions class
public static class HtmlExtensions
{
public static MvcHtmlString Image(this HtmlHelper html, byte[] image)
{
var img = String.Format("data:image/jpg;base64,{0}", Convert.ToBase64String(image));
return new MvcHtmlString("<img src='" + img + "' />");
}
}
then you can do this in any view
@Html.Image(Model.ImgBytes)
How to read file with async/await properly?
Since Node v11.0.0 fs promises are available natively without promisify
:
const fs = require('fs').promises;
async function loadMonoCounter() {
const data = await fs.readFile("monolitic.txt", "binary");
return new Buffer(data);
}
Last executed queries for a specific database
This works for me to find queries on any database in the instance. I'm sysadmin on the instance (check your privileges):
SELECT deqs.last_execution_time AS [Time], dest.text AS [Query], dest.*
FROM sys.dm_exec_query_stats AS deqs
CROSS APPLY sys.dm_exec_sql_text(deqs.sql_handle) AS dest
WHERE dest.dbid = DB_ID('msdb')
ORDER BY deqs.last_execution_time DESC
This is the same answer that Aaron Bertrand provided but it wasn't placed in an answer.
selecting unique values from a column
Use something like this in case you also want to output products details per date as JSON and the MySQL
version does not support JSON
functions.
SELECT `date`,
CONCAT('{',GROUP_CONCAT('{\"id\": \"',`product_id`,'\",\"name\": \"',`product_name`,'\"}'),'}') as `productsJSON`
FROM `buy` group by `date`
order by `date` DESC
product_id product_name date
| 1 | azd | 2011-12-12 |
| 2 | xyz | 2011-12-12 |
| 3 | ase | 2011-12-11 |
| 4 | azwed | 2011-12-11 |
| 5 | wed | 2011-12-10 |
| 6 | cvg | 2011-12-10 |
| 7 | cvig | 2011-12-09 |
RESULT
date productsJSON
2011-12-12T00:00:00Z {{"id": "1","name": "azd"},{"id": "2","name": "xyz"}}
2011-12-11T00:00:00Z {{"id": "3","name": "ase"},{"id": "4","name": "azwed"}}
2011-12-10T00:00:00Z {{"id": "5","name": "wed"},{"id": "6","name": "cvg"}}
2011-12-09T00:00:00Z {{"id": "7","name": "cvig"}}
Try it out in SQL Fiddle
If you are using a MySQL
version that supports JSON
functions then the above query could be re-written:
SELECT `date`,JSON_OBJECTAGG(CONCAT('product-',`product_id`),JSON_OBJECT('id', `product_id`, 'name', `product_name`)) as `productsJSON`
FROM `buy` group by `date`
order by `date` DESC;
Try both in DB Fiddle
Disable autocomplete via CSS
I just use 'new-password'
instead 'off'
on autocomplete.
and I also have try using this code and works (at least on my end), I use WP and GravityForm for your information
$('input').attr('autocomplete','new-password');
Flatten nested dictionaries, compressing keys
If you want to flat nested dictionary and want all unique keys list then here is the solution:
def flat_dict_return_unique_key(data, unique_keys=set()):
if isinstance(data, dict):
[unique_keys.add(i) for i in data.keys()]
for each_v in data.values():
if isinstance(each_v, dict):
flat_dict_return_unique_key(each_v, unique_keys)
return list(set(unique_keys))
Simple way to compare 2 ArrayLists
List<String> oldList = Arrays.asList("a", "b", "c", "d", "e", "f");
List<String> modifiedList = Arrays.asList("a", "b", "c", "d", "e", "g");
List<String> added = new HashSet<>(modifiedList);
List<String> removed = new HashSet<>(oldList);
modifiedList.stream().filter(removed::remove).forEach(added::remove);
// added items
System.out.println(added);
// removed items
System.out.println(removed);
How to get current screen width in CSS?
Use the CSS3 Viewport-percentage feature.
Viewport-Percentage Explanation
Assuming you want the body width size to be a ratio of the browser's view port. I added a border so you can see the body resize as you change your browser width or height. I used a ratio of 90% of the view-port size.
_x000D_
_x000D_
<!DOCTYPE html>_x000D_
<html lang="en">_x000D_
<head>_x000D_
<title>Styles</title>_x000D_
_x000D_
<style>_x000D_
@media screen and (min-width: 480px) {_x000D_
body {_x000D_
background-color: skyblue;_x000D_
width: 90vw;_x000D_
height: 90vh;_x000D_
border: groove black;_x000D_
}_x000D_
_x000D_
div#main {_x000D_
font-size: 3vw;_x000D_
}_x000D_
}_x000D_
</style>_x000D_
_x000D_
</head>_x000D_
<body>_x000D_
<div id="main">_x000D_
Viewport-Percentage Test_x000D_
</div>_x000D_
</body>_x000D_
</html>
_x000D_
_x000D_
_x000D_
how to create Socket connection in Android?
Here, in this post you will find the detailed code for establishing socket between devices or between two application in the same mobile.
You have to create two application to test below code.
In both application's manifest file, add below permission
<uses-permission android:name="android.permission.INTERNET" />
1st App code: Client Socket
activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">
<TableRow
android:id="@+id/tr_send_message"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:gravity="center"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:layout_alignParentTop="true"
android:layout_marginTop="11dp">
<EditText
android:id="@+id/edt_send_message"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:layout_marginRight="10dp"
android:layout_marginLeft="10dp"
android:hint="Enter message"
android:inputType="text" />
<Button
android:id="@+id/btn_send"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginRight="10dp"
android:text="Send" />
</TableRow>
<ScrollView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:layout_below="@+id/tr_send_message"
android:layout_marginTop="25dp"
android:id="@+id/scrollView2">
<TextView
android:id="@+id/tv_reply_from_server"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical" />
</ScrollView>
</RelativeLayout>
MainActivity.java
import android.os.Bundle;
import android.os.Handler;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.net.Socket;
/**
* Created by Girish Bhalerao on 5/4/2017.
*/
public class MainActivity extends AppCompatActivity implements View.OnClickListener {
private TextView mTextViewReplyFromServer;
private EditText mEditTextSendMessage;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button buttonSend = (Button) findViewById(R.id.btn_send);
mEditTextSendMessage = (EditText) findViewById(R.id.edt_send_message);
mTextViewReplyFromServer = (TextView) findViewById(R.id.tv_reply_from_server);
buttonSend.setOnClickListener(this);
}
@Override
public void onClick(View v) {
switch (v.getId()) {
case R.id.btn_send:
sendMessage(mEditTextSendMessage.getText().toString());
break;
}
}
private void sendMessage(final String msg) {
final Handler handler = new Handler();
Thread thread = new Thread(new Runnable() {
@Override
public void run() {
try {
//Replace below IP with the IP of that device in which server socket open.
//If you change port then change the port number in the server side code also.
Socket s = new Socket("xxx.xxx.xxx.xxx", 9002);
OutputStream out = s.getOutputStream();
PrintWriter output = new PrintWriter(out);
output.println(msg);
output.flush();
BufferedReader input = new BufferedReader(new InputStreamReader(s.getInputStream()));
final String st = input.readLine();
handler.post(new Runnable() {
@Override
public void run() {
String s = mTextViewReplyFromServer.getText().toString();
if (st.trim().length() != 0)
mTextViewReplyFromServer.setText(s + "\nFrom Server : " + st);
}
});
output.close();
out.close();
s.close();
} catch (IOException e) {
e.printStackTrace();
}
}
});
thread.start();
}
}
2nd App Code - Server Socket
activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">
<Button
android:id="@+id/btn_stop_receiving"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="STOP Receiving data"
android:layout_alignParentTop="true"
android:enabled="false"
android:layout_centerHorizontal="true"
android:layout_marginTop="89dp" />
<ScrollView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_below="@+id/btn_stop_receiving"
android:layout_marginTop="35dp"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true">
<TextView
android:id="@+id/tv_data_from_client"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical" />
</ScrollView>
<Button
android:id="@+id/btn_start_receiving"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="START Receiving data"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true"
android:layout_marginTop="14dp" />
</RelativeLayout>
MainActivity.java
import android.os.Bundle;
import android.os.Handler;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.ServerSocket;
import java.net.Socket;
/**
* Created by Girish Bhalerao on 5/4/2017.
*/
public class MainActivity extends AppCompatActivity implements View.OnClickListener {
final Handler handler = new Handler();
private Button buttonStartReceiving;
private Button buttonStopReceiving;
private TextView textViewDataFromClient;
private boolean end = false;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
buttonStartReceiving = (Button) findViewById(R.id.btn_start_receiving);
buttonStopReceiving = (Button) findViewById(R.id.btn_stop_receiving);
textViewDataFromClient = (TextView) findViewById(R.id.tv_data_from_client);
buttonStartReceiving.setOnClickListener(this);
buttonStopReceiving.setOnClickListener(this);
}
private void startServerSocket() {
Thread thread = new Thread(new Runnable() {
private String stringData = null;
@Override
public void run() {
try {
ServerSocket ss = new ServerSocket(9002);
while (!end) {
//Server is waiting for client here, if needed
Socket s = ss.accept();
BufferedReader input = new BufferedReader(new InputStreamReader(s.getInputStream()));
PrintWriter output = new PrintWriter(s.getOutputStream());
stringData = input.readLine();
output.println("FROM SERVER - " + stringData.toUpperCase());
output.flush();
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
e.printStackTrace();
}
updateUI(stringData);
if (stringData.equalsIgnoreCase("STOP")) {
end = true;
output.close();
s.close();
break;
}
output.close();
s.close();
}
ss.close();
} catch (IOException e) {
e.printStackTrace();
}
}
});
thread.start();
}
private void updateUI(final String stringData) {
handler.post(new Runnable() {
@Override
public void run() {
String s = textViewDataFromClient.getText().toString();
if (stringData.trim().length() != 0)
textViewDataFromClient.setText(s + "\n" + "From Client : " + stringData);
}
});
}
@Override
public void onClick(View v) {
switch (v.getId()) {
case R.id.btn_start_receiving:
startServerSocket();
buttonStartReceiving.setEnabled(false);
buttonStopReceiving.setEnabled(true);
break;
case R.id.btn_stop_receiving:
//stopping server socket logic you can add yourself
buttonStartReceiving.setEnabled(true);
buttonStopReceiving.setEnabled(false);
break;
}
}
}
"Uncaught Error: [$injector:unpr]" with angular after deployment
If you have separated files for angular app\resources\directives and other stuff then you can just disable minification of your angular app bundle like this (use new Bundle() instead of ScriptBundle() in your bundle config file):
bundles.Add(
new Bundle("~/bundles/angular/SomeBundleName").Include(
"~/Content/js/angular/Pages/Web/MainPage/angularApi.js",
"~/Content/js/angular/Pages/Web/MainPage/angularApp.js",
"~/Content/js/angular/Pages/Web/MainPage/angularCtrl.js"));
And angular app would appear in bundle unmodified.
How to get address location from latitude and longitude in Google Map.?
You have to make one ajax call to get the required result, in this case you can use Google API to get the same
http://maps.googleapis.com/maps/api/geocode/json?latlng=40.714224,-73.961452&sensor=true/false
Build this kind of url and replace the lat long with the one you want to. do the call and response will be in JSON, parse the JSON and you will get the complete address up to street level
Get last n lines of a file, similar to tail
I found a probably the easiest way to find the first or last N lines of a file
Last N lines of a file(For Ex:N=10)
file=open("xyz.txt",'r")
liner=file.readlines()
for ran in range((len(liner)-N),len(liner)):
print liner[ran]
First N lines of a file(For Ex:N=10)
file=open("xyz.txt",'r")
liner=file.readlines()
for ran in range(0,N+1):
print liner[ran]
How to get an object's properties in JavaScript / jQuery?
To get listing of object properties/values:
In Firefox - Firebug:
console.dir(<object>);
Standard JS to get object keys borrowed from Slashnick:
var fGetKeys = function(obj){
var keys = [];
for(var key in obj){
keys.push(key);
}
return keys;
}
// Example to call it:
var arrKeys = fGetKeys(document);
for (var i=0, n=arrKeys.length; i<n; i++){
console.log(i+1 + " - " + arrKeys[i] + document[arrKeys[i]] + "\n");
}
Edits:
<object>
in the above is to be replaced with the variable reference to the object.
console.log()
is to be used in the console, if you're unsure what that is, you can replace it with an alert()
Question mark characters displaying within text, why is this?
Check the character set being emitted by your mirrored server. There appears to be a difference from that to the main server -- the live site appears to be outputting Unicode, where the mirror is not. Also, it's usually a good idea to scrub Unicode characters in your incoming content and replace them with their appropriate HTML entities.
Your specific issue regards "smart quotes," "em dashes" and "en dashes." I know you can replace em dashes with —
and n-dashes with –
(which should be done on the input side of your database); I don't know what the correct replacement for the smart quotes would be. (I usually just replace all curly single quotes with ' and all curly double quotes with " ... Typography geeks may feel free to shoot me on sight.)
I should note that some browsers are more forgiving than others with this issue -- Internet Explorer on Windows tends to auto-magically detect and "fix" this; Firefox and most other browsers display the question marks.
Use curly braces to initialize a Set in Python
There are two obvious issues with the set literal syntax:
my_set = {'foo', 'bar', 'baz'}
It's not available before Python 2.7
There's no way to express an empty set using that syntax (using {}
creates an empty dict)
Those may or may not be important to you.
The section of the docs outlining this syntax is here.
how to add values to an array of objects dynamically in javascript?
You have to instantiate the object first. The simplest way is:
var lab =["1","2","3"];
var val = [42,55,51,22];
var data = [];
for(var i=0; i<4; i++) {
data.push({label: lab[i], value: val[i]});
}
Or an other, less concise way, but closer to your original code:
for(var i=0; i<4; i++) {
data[i] = {}; // creates a new object
data[i].label = lab[i];
data[i].value = val[i];
}
array()
will not create a new array (unless you defined that function). Either Array()
or new Array()
or just []
.
I recommend to read the MDN JavaScript Guide.
Remove Array Value By index in jquery
Your syntax is incorrect, you should either specify a hash:
hash = {abc: true, def: true, ghi: true};
Or an array:
arr = ['abc','def','ghi'];
You can effectively remove an item from a hash by simply setting it to null:
hash['def'] = null;
hash.def = null;
Or removing it entirely:
delete hash.def;
To remove an item from an array you have to iterate through each item and find the one you want (there may be duplicates). You could use array searching and splicing methods:
arr.splice(arr.indexOf("def"), 1);
This finds the first index of "def" and then removes it from the array with splice.
However I would recommend .filter() because it gives you more control:
arr.filter(function(item) { return item !== 'def'; });
This will create a new array with only elements that are not 'def'.
It is important to note that arr.filter() will return a new array, while arr.splice will modify the original array and return the removed elements. These can both be useful, depending on what you want to do with the items.
select2 onchange event only works once
As of version 4.0.0, events such as select2-selecting
, no longer work. They are renamed as follows:
- select2-close is now select2:close
- select2-open is now select2:open
- select2-opening is now select2:opening
- select2-selecting is now select2:selecting
- select2-removed is now select2:removed
- select2-removing is now select2:unselecting
Ref: https://select2.org/programmatic-control/events
_x000D_
_x000D_
(function($){_x000D_
$('.select2').select2();_x000D_
_x000D_
$('.select2').on('select2:selecting', function(e) {_x000D_
console.log('Selecting: ' , e.params.args.data);_x000D_
});_x000D_
})(jQuery);
_x000D_
body{_x000D_
font-family: sans-serif;_x000D_
}_x000D_
_x000D_
.select2{_x000D_
width: 100%;_x000D_
}
_x000D_
<link href="https://cdnjs.cloudflare.com/ajax/libs/select2/4.0.3/css/select2.min.css" rel="stylesheet">_x000D_
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>_x000D_
<script src="https://cdnjs.cloudflare.com/ajax/libs/select2/4.0.3/js/select2.full.min.js"></script>_x000D_
_x000D_
<select class="select2" multiple="multiple">_x000D_
<option value="1">Option 1</option>_x000D_
<option value="2">Option 2</option>_x000D_
<option value="3">Option 3</option>_x000D_
<option value="4">Option 4</option>_x000D_
<option value="5">Option 5</option>_x000D_
<option value="6">Option 6</option>_x000D_
<option value="7">Option 7</option>_x000D_
</select>
_x000D_
_x000D_
_x000D_
How to get all keys with their values in redis
There is no native way of doing this.
The Redis command documentation contains no native commands for getting the key and value of multiple keys.
The most native way of doing this would be to load a lua script into your redis using the SCRIPT LOAD
command or the EVAL
command.
Bash Haxx solution
A workaround would be to use some bash magic, like this:
echo 'keys YOURKEY*' | redis-cli | sed 's/^/get /' | redis-cli
This will output the data from all the keys which begin with YOURKEY
Note that the keys command is a blocking operation and should be used with care.
UINavigationBar Hide back Button Text
In the interface builder, you can select the navigation item of the previous controller and change the Back Button
string to what you'd like the back button to appear as. If you want it blank, for example, just put a space.
You can also change it with this line of code:
[self.navigationItem.backBarButtonItem setTitle:@"Title here"];
Or in Swift:
self.navigationItem.backBarButtonItem?.title = ""
Two-dimensional array in Swift
You should be careful when you're using Array(repeating: Array(repeating: {value}, count: 80), count: 24)
.
If the value is an object, which is initialized by MyClass()
, then they will use the same reference.
Array(repeating: Array(repeating: MyClass(), count: 80), count: 24)
doesn't create a new instance of MyClass
in each array element. This method only creates MyClass
once and puts it into the array.
Here's a safe way to initialize a multidimensional array.
private var matrix: [[MyClass]] = MyClass.newMatrix()
private static func newMatrix() -> [[MyClass]] {
var matrix: [[MyClass]] = []
for i in 0...23 {
matrix.append( [] )
for _ in 0...79 {
matrix[i].append( MyClass() )
}
}
return matrix
}
MySQL: When is Flush Privileges in MySQL really needed?
2 points in addition to all other good answers:
1:
what are the Grant Tables?
from dev.mysql.com
The MySQL system database includes several grant tables that contain information about user accounts and the privileges held by them.
clari?cation: in MySQL, there are some inbuilt databases , one of them is "mysql" , all the tables on "mysql" database have been called as grant tables
2:
note that if you perform:
UPDATE a_grant_table SET password=PASSWORD('1234') WHERE test_col = 'test_val';
and refresh phpMyAdmin , you'll realize that your password has been changed on that table but even now if you perform:
mysql -u someuser -p
your access will be denied by your new password until you perform :
FLUSH PRIVILEGES;
How do you align left / right a div without using float?
No need to add extra elements. While flexbox uses very non-intuitive property names if you know what it can do you'll find yourself using it quite often.
<div style="display: flex; justify-content: space-between;">
<span>Item Left</span>
<span>Item Right</span>
</div>
Plan on needing this often?
.align_between {display: flex; justify-content: space-between;}
I see other people using secondary words in the primary position which makes a mess of information hierarchy. If align is the primary task and right, left, and/or between are the secondary the class should be .align_outer
, not .outer_align
as it will make sense as you vertically scan your code:
.align_between {}
.align_left {}
.align_outer {}
.align_right {}
Good habits over time will allow you to get to bed sooner than later.
How to extract a single value from JSON response?
using json.loads
will turn your data into a python dictionary.
Dictionaries values are accessed using ['key']
resp_str = {
"name" : "ns1:timeSeriesResponseType",
"declaredType" : "org.cuahsi.waterml.TimeSeriesResponseType",
"scope" : "javax.xml.bind.JAXBElement$GlobalScope",
"value" : {
"queryInfo" : {
"creationTime" : 1349724919000,
"queryURL" : "http://waterservices.usgs.gov/nwis/iv/",
"criteria" : {
"locationParam" : "[ALL:103232434]",
"variableParam" : "[00060, 00065]"
},
"note" : [ {
"value" : "[ALL:103232434]",
"title" : "filter:sites"
}, {
"value" : "[mode=LATEST, modifiedSince=null]",
"title" : "filter:timeRange"
}, {
"value" : "sdas01",
"title" : "server"
} ]
}
},
"nil" : false,
"globalScope" : true,
"typeSubstituted" : false
}
would translate into a python diction
resp_dict = json.loads(resp_str)
resp_dict['name'] # "ns1:timeSeriesResponseType"
resp_dict['value']['queryInfo']['creationTime'] # 1349724919000
How to convert a file into a dictionary?
If you love one liners, try:
d=eval('{'+re.sub('\'[\s]*?\'','\':\'',re.sub(r'([^'+input('SEP: ')+',]+)','\''+r'\1'+'\'',open(input('FILE: ')).read().rstrip('\n').replace('\n',',')))+'}')
Input FILE = Path to file, SEP = Key-Value separator character
Not the most elegant or efficient way of doing it, but quite interesting nonetheless :)
How to create an Excel File with Nodejs?
You should check ExcelJS
Works with CSV and XLSX formats.
Great for reading/writing XLSX streams. I've used it to stream an XLSX download to an Express response object, basically like this:
app.get('/some/route', function(req, res) {
res.writeHead(200, {
'Content-Disposition': 'attachment; filename="file.xlsx"',
'Transfer-Encoding': 'chunked',
'Content-Type': 'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet'
})
var workbook = new Excel.stream.xlsx.WorkbookWriter({ stream: res })
var worksheet = workbook.addWorksheet('some-worksheet')
worksheet.addRow(['foo', 'bar']).commit()
worksheet.commit()
workbook.commit()
}
Works great for large files, performs much better than excel4node (got huge memory usage & Node process "out of memory" crash after nearly 5 minutes for a file containing 4 million cells in 20 sheets) since its streaming capabilities are much more limited (does not allows to "commit()" data to retrieve chunks as soon as they can be generated)
See also this SO answer.
Iterate through string array in Java
String current = elements[i];
if (i != elements.length - 1) {
String next = elements[i+1];
}
This makes sure you don't get an ArrayIndexOutOfBoundsException
for the last element (there is no 'next' there). The other option is to iterate to i < elements.length - 1
. It depends on your requirements.
Android MediaPlayer Stop and Play
According to the MediaPlayer
life cycle, which you can view in the Android API guide, I think that you have to call reset()
instead of stop()
, and after that prepare again the media player (use only one) to play the sound from the beginning. Take also into account that the sound may have finished. So I would also recommend to implement setOnCompletionListener()
to make sure that if you try to play again the sound it doesn't fail.
How to add a JAR in NetBeans
You want to add libraries to your project and in doing so you have two options as you yourself identified:
Compile-time libraries are libraries which is needed to compile your application. They are not included when your application is assembled (e.g., into a war-file). Libraries of this kind must be provided by the container running your project.
This is useful in situation when
you want to vary API and implementation, or when the library is supplied by the container (which is typically the case with javax.servlet which is required to compile but provided by the application server, e.g., Apache Tomcat).
Run-time libraries are libraries which is needed both for compilation and when running your project. This is probably what you want in most cases. If for instance your project is packaged into a war/ear, then these libraries will be included in the package.
As for the other alernatives you have either global libraries using Library Manager
or jdk libraries. The latter is simply your regular java libraries, while the former is just a way for your to store a set of libraries under a common name. For all your future projects, instead of manually assigning the libraries you can simply select to import them from your Library Manager
.
Difference between two dates in years, months, days in JavaScript
Neither of the codes work for me, so I use this instead for months and days:
function monthDiff(d2, d1) {
var months;
months = (d2.getFullYear() - d1.getFullYear()) * 12;
months -= d1.getMonth() + 1;
months += d2.getMonth() + 1;
return months <= 0 ? 0 : months;
}
function daysInMonth(date) {
return new Date(date.getYear(), date.getMonth() + 1, 0).getDate();
}
function diffDate(date1, date2) {
if (date2 && date2.getTime() && !isNaN(date2.getTime())) {
var months = monthDiff(date1, date2);
var days = 0;
if (date1.getUTCDate() >= date2.getUTCDate()) {
days = date1.getUTCDate() - date2.getUTCDate();
}
else {
months--;
days = date1.getUTCDate() - date2.getUTCDate() + daysInMonth(date2);
}
// Use the variables months and days how you need them.
}
}
Anaconda Installed but Cannot Launch Navigator
What finally worked for me was:
- Uninstalling Anaconda
- Deleting all files that has "conda" in them - most of them should be
located in: C:\Users\Admin
- Delete especially the "condarc" file.
- Reboot
- Installed 32-bit installer (even though my system is 64-bit) and reboot
Finally worked. I have not yet re-tried with 64-bit installer, since I have a time critical project, but will do when again I have spare time.
P.S. what broke Anaconda for me was a blue screen I got while updating Anaconda. I guess it did not clear all old files and this broke the new installs.
Deserialize JSON with Jackson into Polymorphic Types - A Complete Example is giving me a compile error
If using the fasterxml then,
these changes might be needed
import com.fasterxml.jackson.core.JsonParser;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.core.Version;
import com.fasterxml.jackson.databind.DeserializationContext;
import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.deser.std.StdDeserializer;
import com.fasterxml.jackson.databind.module.SimpleModule;
import com.fasterxml.jackson.databind.node.ObjectNode;
in main method--
use
SimpleModule module =
new SimpleModule("PolymorphicAnimalDeserializerModule");
instead of
new SimpleModule("PolymorphicAnimalDeserializerModule",
new Version(1, 0, 0, null));
and in Animal deserialize() function, make below changes
//Iterator<Entry<String, JsonNode>> elementsIterator = root.getFields();
Iterator<Entry<String, JsonNode>> elementsIterator = root.fields();
//return mapper.readValue(root, animalClass);
return mapper.convertValue(root, animalClass);
This works for fasterxml.jackson. If it still complains of the class fields. Use the same format as in the json for the field names (with "_" -underscore). as this
//mapper.setPropertyNamingStrategy(new CamelCaseNamingStrategy());
might not be supported.
abstract class Animal
{
public String name;
}
class Dog extends Animal
{
public String breed;
public String leash_color;
}
class Cat extends Animal
{
public String favorite_toy;
}
class Bird extends Animal
{
public String wing_span;
public String preferred_food;
}
How to display errors for my MySQLi query?
mysqli_error()
As in:
$sql = "Your SQL statement here";
$result = mysqli_query($conn, $sql) or trigger_error("Query Failed! SQL: $sql - Error: ".mysqli_error($conn), E_USER_ERROR);
Trigger error is better than die because you can use it for development AND production, it's the permanent solution.
Can I get the name of the currently running function in JavaScript?
Information is actual on 2016 year.
Results for function declaration
Result in the Opera
>>> (function func11 (){
... console.log(
... 'Function name:',
... arguments.callee.toString().match(/function\s+([_\w]+)/)[1])
... })();
...
... (function func12 (){
... console.log('Function name:', arguments.callee.name)
... })();
Function name:, func11
Function name:, func12
Result in the Chrome
(function func11 (){
console.log(
'Function name:',
arguments.callee.toString().match(/function\s+([_\w]+)/)[1])
})();
(function func12 (){
console.log('Function name:', arguments.callee.name)
})();
Function name: func11
Function name: func12
Result in the NodeJS
> (function func11 (){
... console.log(
..... 'Function name:',
..... arguments.callee.toString().match(/function\s+([_\w]+)/)[1])
... })();
Function name: func11
undefined
> (function func12 (){
... console.log('Function name:', arguments.callee.name)
... })();
Function name: func12
Does not work in the Firefox. Untested on the IE and the Edge.
Results for function expressions
Result in the NodeJS
> var func11 = function(){
... console.log('Function name:', arguments.callee.name)
... }; func11();
Function name: func11
Result in the Chrome
var func11 = function(){
console.log('Function name:', arguments.callee.name)
}; func11();
Function name: func11
Does not work in the Firefox, Opera. Untested on the IE and the Edge.
Notes:
- Anonymous function does not to make sense to check.
- Testing environment
~ $ google-chrome --version
Google Chrome 53.0.2785.116
~ $ opera --version
Opera 12.16 Build 1860 for Linux x86_64.
~ $ firefox --version
Mozilla Firefox 49.0
~ $ node
node nodejs
~ $ nodejs --version
v6.8.1
~ $ uname -a
Linux wlysenko-Aspire 3.13.0-37-generic #64-Ubuntu SMP Mon Sep 22 21:28:38 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux
Java: how to import a jar file from command line
You could run it without the -jar
command line argument if you happen to know the name of the main class you wish to run:
java -classpath .;myjar.jar;lib/referenced-class.jar my.package.MainClass
If perchance you are using linux, you should use ":" instead of ";" in the classpath.
Xcode 6.1 Missing required architecture X86_64 in file
Many use the build scripts found either here:
http://www.raywenderlich.com/41377/creating-a-static-library-in-ios-tutorial
or here:
https://gist.github.com/sponno/7228256 for their run script in their target.
I was pulling my hair out trying to add x86_64, i386, armv7s, armv7, and arm64 to the Architectures section, only to find lipo -info targetname.a
never returning these architectures after a successful build.
In my case, I had to modify the target runscript, specifically step 1 from the gist link, to manually include the architectures using -arch.
Step 1. Build Device and Simulator versions
xcodebuild -target ${PROJECT_NAME} ONLY_ACTIVE_ARCH=NO -configuration ${CONFIGURATION} -sdk iphoneos BUILD_DIR="${BUILD_DIR}"
BUILD_ROOT="${BUILD_ROOT}" xcodebuild -target ${PROJECT_NAME} -configuration ${CONFIGURATION} -sdk iphonesimulator -arch x86_64 -arch i386 -arch armv7 -arch armv7s -arch arm64 BUILD_DIR="${BUILD_DIR}" BUILD_ROOT="${BUILD_ROOT}"
Could you explain STA and MTA?
As my understanding, the 'Apartment' is used to protect the COM objects from multi-threading issues.
If a COM object is not thread-safe, it should declare it as a STA object. Then only the thread who creates it can access it. The creation thread should declare itself as a STA thread. Under the hood, the thread stores the STA information in its TLS(Thread Local Storage). We call this behavior as that the thread enters a STA apartment. When other threads want to access this COM object, it should marshal the access to the creation thread. Basically, the creation thread uses messages mechanism to process the in-bound calls.
If a COM object is thread-safe, it should declare it as a MTA object. The MTA object can be accessed by multi-threads.
How to resize array in C++?
You can do smth like this for 1D arrays. Here we use int*& because we want our pointer to be changeable.
#include<algorithm> // for copy
void resize(int*& a, size_t& n)
{
size_t new_n = 2 * n;
int* new_a = new int[new_n];
copy(a, a + n, new_a);
delete[] a;
a = new_a;
n = new_n;
}
For 2D arrays:
#include<algorithm> // for copy
void resize(int**& a, size_t& n)
{
size_t new_n = 2 * n, i = 0;
int** new_a = new int* [new_n];
for (i = 0; i != new_n; ++i)
new_a[i] = new int[100];
for (i = 0; i != n; ++i)
{
copy(a[i], a[i] + 100, new_a[i]);
delete[] a[i];
}
delete[] a;
a = new_a;
n = new_n;
}
Invoking of 1D array:
void myfn(int*& a, size_t& n)
{
// do smth
resize(a, n);
}
Invoking of 2D array:
void myfn(int**& a, size_t& n)
{
// do smth
resize(a, n);
}
R - Concatenate two dataframes?
You may use rbind
but in this case you need to have the same number of columns in both tables, so try the following:
b$b<-as.double(NA) #keeping numeric format is essential for further calculations
new<-rbind(a,b)
Set value of textarea in jQuery
This works:
var t = $('#taCommentSalesAdministration');
t.val('Hi');
Remember, the tricky part here is making sure you use the correct ID.
And before you use the ID make sure you put #
before it.
Jasmine JavaScript Testing - toBe vs toEqual
To quote the jasmine github project,
expect(x).toEqual(y);
compares objects or primitives x and y and
passes if they are equivalent
expect(x).toBe(y);
compares objects or primitives x and y and passes
if they are the same object
CSS3 Transform Skew One Side
Maybe you want to use CSS "clip-path" (Works with transparency and background)
"clip-path" reference: https://developer.mozilla.org/en-US/docs/Web/CSS/clip-path
Generator: http://bennettfeely.com/clippy/
Example:
_x000D_
_x000D_
/* With percent */_x000D_
.element-percent {_x000D_
background: red;_x000D_
width: 150px;_x000D_
height: 48px;_x000D_
display: inline-block;_x000D_
_x000D_
clip-path: polygon(0 0, 100% 0%, 75% 100%, 0% 100%);_x000D_
}_x000D_
_x000D_
/* With pixel */_x000D_
.element-pixel {_x000D_
background: blue;_x000D_
width: 150px;_x000D_
height: 48px;_x000D_
display: inline-block;_x000D_
_x000D_
clip-path: polygon(0 0, 100% 0%, calc(100% - 32px) 100%, 0% 100%);_x000D_
}_x000D_
_x000D_
/* With background */_x000D_
.element-background {_x000D_
background: url(https://images.pexels.com/photos/170811/pexels-photo-170811.jpeg?auto=compress&cs=tinysrgb&dpr=2&h=750&w=1260) no-repeat center/cover;_x000D_
width: 150px;_x000D_
height: 48px;_x000D_
display: inline-block;_x000D_
_x000D_
clip-path: polygon(0 0, 100% 0%, calc(100% - 32px) 100%, 0% 100%);_x000D_
}
_x000D_
<div class="element-percent"></div>_x000D_
_x000D_
<br />_x000D_
_x000D_
<div class="element-pixel"></div>_x000D_
_x000D_
<br />_x000D_
_x000D_
<div class="element-background"></div>
_x000D_
_x000D_
_x000D_
Change the current directory from a Bash script
In light of the unreadability and overcomplication of answers, i believe this is what the requestor should do
- add that script to the
PATH
- run the script as
. scriptname
The .
(dot) will make sure the script is not run in a child shell.
Change text from "Submit" on input tag
The value
attribute is used to determine the rendered label of a submit input.
<input type="submit" class="like" value="Like" />
Note that if the control is successful (this one won't be as it has no name
) this will also be the submitted value for it.
To have a different submitted value and label you need to use a button element, in which the textNode inside the element determines the label. You can include other elements (including <img>
here).
<button type="submit" class="like" name="foo" value="bar">Like</button>
Note that support for <button>
is dodgy in older versions of Internet Explorer.
How can I read and manipulate CSV file data in C++?
Here is some code you can use. The data from the csv is stored inside an array of rows. Each row is an array of strings. Hope this helps.
#include <iostream>
#include <string>
#include <fstream>
#include <sstream>
#include <vector>
typedef std::string String;
typedef std::vector<String> CSVRow;
typedef CSVRow::const_iterator CSVRowCI;
typedef std::vector<CSVRow> CSVDatabase;
typedef CSVDatabase::const_iterator CSVDatabaseCI;
void readCSV(std::istream &input, CSVDatabase &db);
void display(const CSVRow&);
void display(const CSVDatabase&);
int main(){
std::fstream file("file.csv", std::ios::in);
if(!file.is_open()){
std::cout << "File not found!\n";
return 1;
}
CSVDatabase db;
readCSV(file, db);
display(db);
}
void readCSV(std::istream &input, CSVDatabase &db){
String csvLine;
// read every line from the stream
while( std::getline(input, csvLine) ){
std::istringstream csvStream(csvLine);
CSVRow csvRow;
String csvCol;
// read every element from the line that is seperated by commas
// and put it into the vector or strings
while( std::getline(csvStream, csvCol, ',') )
csvRow.push_back(csvCol);
db.push_back(csvRow);
}
}
void display(const CSVRow& row){
if(!row.size())
return;
CSVRowCI i=row.begin();
std::cout<<*(i++);
for(;i != row.end();++i)
std::cout<<','<<*i;
}
void display(const CSVDatabase& db){
if(!db.size())
return;
CSVDatabaseCI i=db.begin();
for(; i != db.end(); ++i){
display(*i);
std::cout<<std::endl;
}
}
mysql query: SELECT DISTINCT column1, GROUP BY column2
Somehow your requirement sounds a bit contradictory ..
group by name (which is basically a distinct on name plus readiness to aggregate) and then a distinct on IP
What do you think should happen if two people (names) worked from the same IP within the time period specified?
Did you try this?
SELECT name, COUNT(name), time, price, ip, SUM(price)
FROM tablename
WHERE time >= $yesterday AND time <$today
GROUP BY name,ip
SSH to Elastic Beanstalk instance
Elastic Beanstalk can bind a single EC2 keypair to an instance profile. A manual solution to have multiple users ssh into EBS is to add their public keys in authorized_keys file.
Should you always favor xrange() over range()?
One other difference is that xrange() can't support numbers bigger than C ints, so if you want to have a range using python's built in large number support, you have to use range().
Python 2.7.3 (default, Jul 13 2012, 22:29:01)
[GCC 4.7.1] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> range(123456787676676767676676,123456787676676767676679)
[123456787676676767676676L, 123456787676676767676677L, 123456787676676767676678L]
>>> xrange(123456787676676767676676,123456787676676767676679)
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
OverflowError: Python int too large to convert to C long
Python 3 does not have this problem:
Python 3.2.3 (default, Jul 14 2012, 01:01:48)
[GCC 4.7.1] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> range(123456787676676767676676,123456787676676767676679)
range(123456787676676767676676, 123456787676676767676679)
Understanding ibeacon distancing
The iBeacon output power is measured (calibrated) at a distance of 1 meter. Let's suppose that this is -59 dBm (just an example). The iBeacon will include this number as part of its LE advertisment.
The listening device (iPhone, etc), will measure the RSSI of the device. Let's suppose, for example, that this is, say, -72 dBm.
Since these numbers are in dBm, the ratio of the power is actually the difference in dB. So:
ratio_dB = txCalibratedPower - RSSI
To convert that into a linear ratio, we use the standard formula for dB:
ratio_linear = 10 ^ (ratio_dB / 10)
If we assume conservation of energy, then the signal strength must fall off as 1/r^2. So:
power = power_at_1_meter / r^2
. Solving for r, we get:
r = sqrt(ratio_linear)
In Javascript, the code would look like this:
function getRange(txCalibratedPower, rssi) {
var ratio_db = txCalibratedPower - rssi;
var ratio_linear = Math.pow(10, ratio_db / 10);
var r = Math.sqrt(ratio_linear);
return r;
}
Note, that, if you're inside a steel building, then perhaps there will be internal reflections that make the signal decay slower than 1/r^2. If the signal passes through a human body (water) then the signal will be attenuated. It's very likely that the antenna doesn't have equal gain in all directions. Metal objects in the room may create strange interference patterns. Etc, etc... YMMV.
Can a Windows batch file determine its own file name?
Try to run below example in order to feel how the magical variables work.
@echo off
SETLOCAL EnableDelayedExpansion
echo Full path and filename: %~f0
echo Drive: %~d0
echo Path: %~p0
echo Drive and path: %~dp0
echo Filename without extension: %~n0
echo Filename with extension: %~nx0
echo Extension: %~x0
echo date time : %~t0
echo file size: %~z0
ENDLOCAL
The related rules are following.
%~I - expands %I removing any surrounding quotes ("")
%~fI - expands %I to a fully qualified path name
%~dI - expands %I to a drive letter only
%~pI - expands %I to a path only
%~nI - expands %I to a file name only
%~xI - expands %I to a file extension only
%~sI - expanded path contains short names only
%~aI - expands %I to file attributes of file
%~tI - expands %I to date/time of file
%~zI - expands %I to size of file
%~$PATH:I - searches the directories listed in the PATH
environment variable and expands %I to the
fully qualified name of the first one found.
If the environment variable name is not
defined or the file is not found by the
search, then this modifier expands to the
empty string
Nested select statement in SQL Server
The answer provided by Joe Stefanelli is already correct.
SELECT name FROM (SELECT name FROM agentinformation) as a
We need to make an alias of the subquery because a query needs a table object which we will get from making an alias for the subquery. Conceptually, the subquery results are substituted into the outer query. As we need a table object in the outer query, we need to make an alias of the inner query.
Statements that include a subquery usually take one of these forms:
- WHERE expression [NOT] IN (subquery)
- WHERE expression comparison_operator [ANY | ALL] (subquery)
- WHERE [NOT] EXISTS (subquery)
Check for more subquery rules and subquery types.
More examples of Nested Subqueries.
IN / NOT IN – This operator takes the output of the inner query after the inner query gets executed which can be zero or more values and sends it to the outer query. The outer query then fetches all the matching [IN operator] or non matching [NOT IN operator] rows.
ANY – [>ANY or ANY operator takes the list of values produced by the inner query and fetches all the values which are greater than the minimum value of the list. The
e.g. >ANY(100,200,300), the ANY operator will fetch all the values greater than 100.
- ALL – [>ALL or ALL operator takes the list of values produced by the inner query and fetches all the values which are greater than the maximum of the list. The
e.g. >ALL(100,200,300), the ALL operator will fetch all the values greater than 300.
- EXISTS – The EXISTS keyword produces a Boolean value [TRUE/FALSE]. This EXISTS checks the existence of the rows returned by the sub query.
Count unique values using pandas groupby
I know it has been a while since this was posted, but I think this will help too.
I wanted to count unique values and filter the groups by number of these unique values, this is how I did it:
df.groupby('group').agg(['min','max','count','nunique']).reset_index(drop=False)
Check if any ancestor has a class using jQuery
There are many ways to filter for element ancestors.
if ($elem.closest('.parentClass').length /* > 0*/) {/*...*/}
if ($elem.parents('.parentClass').length /* > 0*/) {/*...*/}
if ($elem.parents().hasClass('parentClass')) {/*...*/}
if ($('.parentClass').has($elem).length /* > 0*/) {/*...*/}
if ($elem.is('.parentClass *')) {/*...*/}
Beware, closest()
method includes element itself while checking for selector.
Alternatively, if you have a unique selector matching the $elem
, e.g #myElem
, you can use:
if ($('.parentClass:has(#myElem)').length /* > 0*/) {/*...*/}
if(document.querySelector('.parentClass #myElem')) {/*...*/}
If you want to match an element depending any of its ancestor class for styling purpose only, just use a CSS rule:
.parentClass #myElem { /* CSS property set */ }
Javascript how to split newline
Here is example with console.log
instead of alert()
. It is more convenient :)
var parse = function(){
var str = $('textarea').val();
var results = str.split("\n");
$.each(results, function(index, element){
console.log(element);
});
};
$(function(){
$('button').on('click', parse);
});
You can try it here
.Net: How do I find the .NET version?
MSDN details it here very nicely on how to check it from registry:
To find .NET Framework versions by viewing the registry (.NET
Framework 1-4)
- On the Start menu, choose Run.
- In the Open box, enter regedit.exe.You must have administrative credentials to run regedit.exe.
In the Registry Editor, open the following subkey:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\NET Framework Setup\NDP
The installed versions are listed under the NDP subkey. The version
number is stored in the Version entry. For the .NET Framework 4 the
Version entry is under the Client or Full subkey (under NDP), or under
both subkeys.
To find .NET Framework versions by viewing the registry (.NET
Framework 4.5 and later)
- On the Start menu, choose Run.
- In the Open box, enter regedit.exe. You must have administrative credentials to run regedit.exe.
In the Registry Editor, open the following subkey:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\NET Framework Setup\NDP\v4\Full
Note that the path to the Full subkey includes the subkey Net
Framework rather than .NET Framework
Check for a DWORD value named Release
. The existence of the Release
DWORD indicates that the .NET Framework 4.5 or newer has been
installed on that computer.
Note: The last row in the above snapshot which got clipped reads On all other OS versions: 461310
. I tried my level best to avoid the information getting clipped while taking the screenshot but the table was way too big.
Reset all changes after last commit in git
First, reset any changes
This will undo any changes you've made to tracked files and restore deleted files:
git reset HEAD --hard
Second, remove new files
This will delete any new files that were added since the last commit:
git clean -fd
Files that are not tracked due to .gitignore
are preserved; they will not be removed
Warning: using -x
instead of -fd
would delete ignored files. You probably don't want to do this.
Best way to verify string is empty or null
Optional.ofNullable(label)
.map(String::trim)
.map(string -> !label.isEmpty)
.orElse(false)
OR
TextUtils.isNotBlank(label);
the last solution will check if not null and trimm the str at the same time
how to concat two columns into one with the existing column name in mysql?
As aziz-shaikh has pointed out, there is no way to suppress an individual column from the *
directive, however you might be able to use the following hack:
SELECT CONCAT(c.FIRSTNAME, ',', c.LASTNAME) AS FIRSTNAME,
c.*
FROM `customer` c;
Doing this will cause the second occurrence of the FIRSTNAME
column to adopt the alias FIRSTNAME_1
so you should be able to safely address your customised FIRSTNAME
column. You need to alias the table because *
in any position other than at the start will fail if not aliased.
Hope that helps!
What is recursion and when should I use it?
There are a number of good explanations of recursion in this thread, this answer is about why you shouldn't use it in most languages.* In the majority of major imperative language implementations (i.e. every major implementation of C, C++, Basic, Python, Ruby,Java, and C#) iteration is vastly preferable to recursion.
To see why, walk through the steps that the above languages use to call a function:
- space is carved out on the stack for the function's arguments and local variables
- the function's arguments are copied into this new space
- control jumps to the function
- the function's code runs
- the function's result is copied into a return value
- the stack is rewound to its previous position
- control jumps back to where the function was called
Doing all of these steps takes time, usually a little bit more than it takes to iterate through a loop. However, the real problem is in step #1. When many programs start, they allocate a single chunk of memory for their stack, and when they run out of that memory (often, but not always due to recursion), the program crashes due to a stack overflow.
So in these languages recursion is slower and it makes you vulnerable to crashing. There are still some arguments for using it though. In general, code written recursively is shorter and a bit more elegant, once you know how to read it.
There is a technique that language implementers can use called tail call optimization which can eliminate some classes of stack overflow. Put succinctly: if a function's return expression is simply the result of a function call, then you don't need to add a new level onto the stack, you can reuse the current one for the function being called. Regrettably, few imperative language-implementations have tail-call optimization built in.
* I love recursion. My favorite static language doesn't use loops at all, recursion is the only way to do something repeatedly. I just don't think that recursion is generally a good idea in languages that aren't tuned for it.
** By the way Mario, the typical name for your ArrangeString function is "join", and I'd be surprised if your language of choice doesn't already have an implementation of it.
How do I check in python if an element of a list is empty?
If you want to know if list element at index i
is set or not, you can simply check the following:
if len(l)<=i:
print ("empty")
If you are looking for something like what is a NULL-Pointer or a NULL-Reference in other languages, Python offers you None
. That is you can write:
l[0] = None # here, list element at index 0 has to be set already
l.append(None) # here the list can be empty before
# checking
if l[i] == None:
print ("list has actually an element at position i, which is None")
How to return a part of an array in Ruby?
another way is to use the range method
foo = [1,2,3,4,5,6]
bar = [10,20,30,40,50,60]
a = foo[0...3]
b = bar[3...6]
print a + b
=> [1, 2, 3, 40, 50 , 60]
Why is 2 * (i * i) faster than 2 * i * i in Java?
(Editor's note: this answer is contradicted by evidence from looking at the asm, as shown by another answer. This was a guess backed up by some experiments, but it turned out not to be correct.)
When the multiplication is 2 * (i * i)
, the JVM is able to factor out the multiplication by 2
from the loop, resulting in this equivalent but more efficient code:
int n = 0;
for (int i = 0; i < 1000000000; i++) {
n += i * i;
}
n *= 2;
but when the multiplication is (2 * i) * i
, the JVM doesn't optimize it since the multiplication by a constant is no longer right before the n +=
addition.
Here are a few reasons why I think this is the case:
- Adding an
if (n == 0) n = 1
statement at the start of the loop results in both versions being as efficient, since factoring out the multiplication no longer guarantees that the result will be the same
- The optimized version (by factoring out the multiplication by 2) is exactly as fast as the
2 * (i * i)
version
Here is the test code that I used to draw these conclusions:
public static void main(String[] args) {
long fastVersion = 0;
long slowVersion = 0;
long optimizedVersion = 0;
long modifiedFastVersion = 0;
long modifiedSlowVersion = 0;
for (int i = 0; i < 10; i++) {
fastVersion += fastVersion();
slowVersion += slowVersion();
optimizedVersion += optimizedVersion();
modifiedFastVersion += modifiedFastVersion();
modifiedSlowVersion += modifiedSlowVersion();
}
System.out.println("Fast version: " + (double) fastVersion / 1000000000 + " s");
System.out.println("Slow version: " + (double) slowVersion / 1000000000 + " s");
System.out.println("Optimized version: " + (double) optimizedVersion / 1000000000 + " s");
System.out.println("Modified fast version: " + (double) modifiedFastVersion / 1000000000 + " s");
System.out.println("Modified slow version: " + (double) modifiedSlowVersion / 1000000000 + " s");
}
private static long fastVersion() {
long startTime = System.nanoTime();
int n = 0;
for (int i = 0; i < 1000000000; i++) {
n += 2 * (i * i);
}
return System.nanoTime() - startTime;
}
private static long slowVersion() {
long startTime = System.nanoTime();
int n = 0;
for (int i = 0; i < 1000000000; i++) {
n += 2 * i * i;
}
return System.nanoTime() - startTime;
}
private static long optimizedVersion() {
long startTime = System.nanoTime();
int n = 0;
for (int i = 0; i < 1000000000; i++) {
n += i * i;
}
n *= 2;
return System.nanoTime() - startTime;
}
private static long modifiedFastVersion() {
long startTime = System.nanoTime();
int n = 0;
for (int i = 0; i < 1000000000; i++) {
if (n == 0) n = 1;
n += 2 * (i * i);
}
return System.nanoTime() - startTime;
}
private static long modifiedSlowVersion() {
long startTime = System.nanoTime();
int n = 0;
for (int i = 0; i < 1000000000; i++) {
if (n == 0) n = 1;
n += 2 * i * i;
}
return System.nanoTime() - startTime;
}
And here are the results:
Fast version: 5.7274411 s
Slow version: 7.6190804 s
Optimized version: 5.1348007 s
Modified fast version: 7.1492705 s
Modified slow version: 7.2952668 s
Mount current directory as a volume in Docker on Windows 10
docker run --rm -v /c/Users/Christian/manager/bin:/app --workdir=/app php:7.2-cli php app.php
Git bash
cd /c/Users/Christian/manager
docker run --rm -v ${PWD}:/app --workdir=/app php:7.2-cli php bin/app.php
echo ${PWD}
result:
/c/Users/Christian/manager
cmd or PowerShell
cd C:\Users\Christian\manager
echo ${PWD}
result:
Path
---- C:\Users\Christian\manager
as we see in cmd or PowerShell $ {PWD} will not work
How to control the line spacing in UILabel
As a quick-dirty-smart-simple workaround:
For UILabels that don't have much lines you can instead use stackViews.
- For each line write a new label.
- Embed them into a StackView.(select both labels-->Editor-->Embed In -->StackView
- Adjust the
Spacing
of the StackView to your desired amount
Be sure to stack them vertically.
This solution also works for custom fonts.
Difference between the System.Array.CopyTo() and System.Array.Clone()
One other difference not mentioned so far is that
- with
Clone()
the destination array need not exist yet since a new one is created from scratch.
- with
CopyTo()
not only does the destination array need to already exist, it needs to be large enough to hold all the elements in the source array from the index you specify as the destination.
'module' object is not callable - calling method in another file
The problem is in the import
line. You are importing a module, not a class. Assuming your file is named other_file.py
(unlike java, again, there is no such rule as "one class, one file"):
from other_file import findTheRange
if your file is named findTheRange too, following java's convenions, then you should write
from findTheRange import findTheRange
you can also import it just like you did with random
:
import findTheRange
operator = findTheRange.findTheRange()
Some other comments:
a) @Daniel Roseman is right. You do not need classes here at all. Python encourages procedural programming (when it fits, of course)
b) You can build the list directly:
randomList = [random.randint(0, 100) for i in range(5)]
c) You can call methods in the same way you do in java:
largestInList = operator.findLargest(randomList)
smallestInList = operator.findSmallest(randomList)
d) You can use built in function, and the huge python library:
largestInList = max(randomList)
smallestInList = min(randomList)
e) If you still want to use a class, and you don't need self
, you can use @staticmethod
:
class findTheRange():
@staticmethod
def findLargest(_list):
#stuff...
Updating version numbers of modules in a multi-module Maven project
The best way is, since you intend to bundle your modules together, you can specify <dependencyManagement>
tag in outer most pom.xml
(parent module) direct under <project>
tag. It controls the version and group name. In your individual module, you just need to specify the <artifactId>
tag in your pom.xml
. It will take the version from parent file.
Make ABC Ordered List Items Have Bold Style
You could do something like this also:
<ol type="A" style="font-weight: bold;">
<li style="padding-bottom: 8px;">****</li>
It is simple code for the beginners.
This code is been tested in "Mozilla, chrome and edge..
GIT commit as different user without email / or only email
The minimal required author format, as hinted to in this SO answer, is
Name <email>
In your case, this means you want to write
git commit --author="Name <email>" -m "whatever"
Per Willem D'Haeseleer's comment, if you don't have an email address, you can use <>
:
git commit --author="Name <>" -m "whatever"
As written on the git commit
man page that you linked to, if you supply anything less than that, it's used as a search token to search through previous commits, looking for other commits by that author.
Magento How to debug blank white screen
It can also be when you don't have a proper php extension loaded. I would double check that you have all of the required php extensions loaded on your system if it isn't the memory limit issue.
NSString property: copy or retain?
For attributes whose type is an immutable value class that conforms to the NSCopying
protocol, you almost always should specify copy
in your @property
declaration. Specifying retain
is something you almost never want in such a situation.
Here's why you want to do that:
NSMutableString *someName = [NSMutableString stringWithString:@"Chris"];
Person *p = [[[Person alloc] init] autorelease];
p.name = someName;
[someName setString:@"Debajit"];
The current value of the Person.name
property will be different depending on whether the property is declared retain
or copy
— it will be @"Debajit"
if the property is marked retain
, but @"Chris"
if the property is marked copy
.
Since in almost all cases you want to prevent mutating an object's attributes behind its back, you should mark the properties representing them copy
. (And if you write the setter yourself instead of using @synthesize
you should remember to actually use copy
instead of retain
in it.)
Getting indices of True values in a boolean list
Use dictionary comprehension way,
x = {k:v for k,v in enumerate(states) if v == True}
Input:
states = [False, False, False, False, True, True, False, True, False, False, False, False, False, False, False, False]
Output:
{4: True, 5: True, 7: True}