How to get week numbers from dates?
If you want to get the week number with the year, Grant Shannon's solution using strftime works, but you need to make some corrections for the dates around january 1st. For instance, 2016-01-03 (yyyy-mm-dd) is week 53 of year 2015, not 2016. And 2018-12-31 is week 1 of 2019, not of 2018. This codes provides some examples and a solution. In column "yearweek" the years are sometimes wrong, in "yearweek2" they are corrected (rows 2 and 5).
library(dplyr)
library(lubridate)
# create a testset
test <- data.frame(matrix(data = c("2015-12-31",
"2016-01-03",
"2016-01-04",
"2018-12-30",
"2018-12-31",
"2019-01-01") , ncol=1, nrow = 6 ))
# add a colname
colnames(test) <- "date_txt"
# this codes provides correct year-week numbers
test <- test %>%
mutate(date = as.Date(date_txt, format = "%Y-%m-%d")) %>%
mutate(yearweek = as.integer(strftime(date, format = "%Y%V"))) %>%
mutate(yearweek2 = ifelse(test = day(date) > 7 & substr(yearweek, 5, 6) == '01',
yes = yearweek + 100,
no = ifelse(test = month(date) == 1 & as.integer(substr(yearweek, 5, 6)) > 51,
yes = yearweek - 100,
no = yearweek)))
# print the result
print(test)
date_txt date yearweek yearweek2
1 2015-12-31 2015-12-31 201553 201553
2 2016-01-03 2016-01-03 201653 201553
3 2016-01-04 2016-01-04 201601 201601
4 2018-12-30 2018-12-30 201852 201852
5 2018-12-31 2018-12-31 201801 201901
6 2019-01-01 2019-01-01 201901 201901
jQuery exclude elements with certain class in selector
To add some info that helped me today, a jQuery object/this
can also be passed in to the .not() selector.
_x000D_
_x000D_
$(document).ready(function(){_x000D_
$(".navitem").click(function(){_x000D_
$(".navitem").removeClass("active");_x000D_
$(".navitem").not($(this)).addClass("active");_x000D_
});_x000D_
});
_x000D_
.navitem_x000D_
{_x000D_
width: 100px;_x000D_
background: red;_x000D_
color: white;_x000D_
display: inline-block;_x000D_
position: relative;_x000D_
text-align: center;_x000D_
}_x000D_
.navitem.active_x000D_
{_x000D_
background:green;_x000D_
}
_x000D_
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>_x000D_
_x000D_
<div class="navitem">Home</div>_x000D_
<div class="navitem">About</div>_x000D_
<div class="navitem">Pricing</div>
_x000D_
_x000D_
_x000D_
The above example can be simplified, but wanted to show the usage of this
in the not()
selector.
Extract images from PDF without resampling, in python?
Try below code. it will extract all image from pdf.
import sys
import PyPDF2
from PIL import Image
pdf=sys.argv[1]
print(pdf)
input1 = PyPDF2.PdfFileReader(open(pdf, "rb"))
for x in range(0,input1.numPages):
xObject=input1.getPage(x)
xObject = xObject['/Resources']['/XObject'].getObject()
for obj in xObject:
if xObject[obj]['/Subtype'] == '/Image':
size = (xObject[obj]['/Width'], xObject[obj]['/Height'])
print(size)
data = xObject[obj]._data
#print(data)
print(xObject[obj]['/Filter'])
if xObject[obj]['/Filter'][0] == '/DCTDecode':
img_name=str(x)+".jpg"
print(img_name)
img = open(img_name, "wb")
img.write(data)
img.close()
print(str(x)+" is done")
What is the best free memory leak detector for a C/C++ program and its plug-in DLLs?
If you don't want to recompile (as Visual Leak Detector requires) I would recommend WinDbg, which is both powerful and fast (though it's not as easy to use as one could desire).
On the other hand, if you don't want to mess with WinDbg, you can take a look at UMDH, which is also developed by Microsoft and it's easier to learn.
Take a look at these links in order to learn more about WinDbg, memory leaks and memory management in general:
DateTime's representation in milliseconds?
Using the answer of Andoma, this is what I'm doing
You can create a Struct or a Class like this one
struct Date
{
public static double GetTime(DateTime dateTime)
{
return dateTime.ToUniversalTime().Subtract(new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc)).TotalMilliseconds;
}
public static DateTime DateTimeParse(double milliseconds)
{
return new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc).AddMilliseconds(milliseconds).ToLocalTime();
}
}
And you can use this in your code as following
DateTime dateTime = DateTime.Now;
double total = Date.GetTime(dateTime);
dateTime = Date.DateTimeParse(total);
I hope this help you
Order by multiple columns with Doctrine
The comment for orderBy
source code notes: Keys are field and values are the order, being either ASC or DESC.
. So you can do orderBy->(['field' => Criteria::ASC])
.
Cross domain POST request is not sending cookie Ajax Jquery
Please note this doesn't solve the cookie sharing process, as in general this is bad practice.
You need to be using JSONP as your type:
From $.ajax documentation:
Cross-domain requests and dataType: "jsonp" requests do not support synchronous operation.
$.ajax(
{
type: "POST",
url: "http://example.com/api/getlist.json",
dataType: 'jsonp',
xhrFields: {
withCredentials: true
},
crossDomain: true,
beforeSend: function(xhr) {
xhr.setRequestHeader("Cookie", "session=xxxyyyzzz");
},
success: function(){
alert('success');
},
error: function (xhr) {
alert(xhr.responseText);
}
}
);
Writelines writes lines without newline, Just fills the file
This is actually a pretty common problem for newcomers to Python—especially since, across the standard library and popular third-party libraries, some reading functions strip out newlines, but almost no writing functions (except the log
-related stuff) add them.
So, there's a lot of Python code out there that does things like:
fw.write('\n'.join(line_list) + '\n')
or
fw.write(line + '\n' for line in line_list)
Either one is correct, and of course you could even write your own writelinesWithNewlines function that wraps it up…
But you should only do this if you can't avoid it.
It's better if you can create/keep the newlines in the first place—as in Greg Hewgill's suggestions:
line_list.append(new_line + "\n")
And it's even better if you can work at a higher level than raw lines of text, e.g., by using the csv module in the standard library, as esuaro suggests.
For example, right after defining fw
, you might do this:
cw = csv.writer(fw, delimiter='|')
Then, instead of this:
new_line = d[looking_for]+'|'+'|'.join(columns[1:])
line_list.append(new_line)
You do this:
row_list.append(d[looking_for] + columns[1:])
And at the end, instead of this:
fw.writelines(line_list)
You do this:
cw.writerows(row_list)
Finally, your design is "open a file, then build up a list of lines to add to the file, then write them all at once". If you're going to open the file up top, why not just write the lines one by one? Whether you're using simple writes or a csv.writer
, it'll make your life simpler, and your code easier to read. (Sometimes there can be simplicity, efficiency, or correctness reasons to write a file all at once—but once you've moved the open
all the way to the opposite end of the program from the write
, you've pretty much lost any benefits of all-at-once.)
How do you underline a text in Android XML?
<resource>
<string name="your_string_here">This is an <u>underline</u>.</string>
</resources>
If it does not work then
<resource>
<string name="your_string_here">This is an <u>underline</u>.</string>
Because "<" could be a keyword at some time.
And for Displaying
TextView textView = (TextView) view.findViewById(R.id.textview);
textView.setText(Html.fromHtml(getString(R.string.your_string_here)));
How to install pip for Python 3 on Mac OS X?
Also, it's worth to mention that Max OSX/macOS users can just use Homebrew to install pip3.
$> brew update
$> brew install python3
$> pip3 --version
pip 9.0.1 from /usr/local/lib/python3.6/site-packages (python 3.6)
PostgreSQL next value of the sequences?
I stumbled upon this question b/c I was trying to find the next sequence value by table. This didn't answer my question however this is how its done, and it may help those looking for the sequence value not by name but by table:
SELECT nextval(pg_get_serial_sequence('<your_table>', 'id')) AS new_id;
Hope it helps :)
Character Limit in HTML
For the <input> element there's the maxlength attribute:
<input type="text" id="Textbox" name="Textbox" maxlength="10" />
(by the way, the type is "text", not "textbox" as others are writing), however, you have to use javascript with <textarea>s. Either way the length should be checked on the server anyway.
How an 'if (A && B)' statement is evaluated?
In C and C++, the &&
and ||
operators "short-circuit". That means that they only evaluate a parameter if required. If the first parameter to &&
is false, or the first to ||
is true, the rest will not be evaluated.
The code you posted is safe, though I question why you'd include an empty else
block.
Oracle SQL Where clause to find date records older than 30 days
Use:
SELECT *
FROM YOUR_TABLE
WHERE creation_date <= TRUNC(SYSDATE) - 30
SYSDATE returns the date & time; TRUNC resets the date to being as of midnight so you can omit it if you want the creation_date
that is 30 days previous including the current time.
Depending on your needs, you could also look at using ADD_MONTHS:
SELECT *
FROM YOUR_TABLE
WHERE creation_date <= ADD_MONTHS(TRUNC(SYSDATE), -1)
Flask Error: "Method Not Allowed The method is not allowed for the requested URL"
What is happening here is that database route does not accept any url methods.
I would try putting the url methods in the app route just like you have in the entry_page function:
@app.route('/entry', methods=['GET', 'POST'])
def entry_page():
if request.method == 'POST':
date = request.form['date']
title = request.form['blog_title']
post = request.form['blog_main']
post_entry = models.BlogPost(date = date, title = title, post = post)
db.session.add(post_entry)
db.session.commit()
return redirect(url_for('database'))
else:
return render_template('entry.html')
@app.route('/database', methods=['GET', 'POST'])
def database():
query = []
for i in session.query(models.BlogPost):
query.append((i.title, i.post, i.date))
return render_template('database.html', query = query)
Bring a window to the front in WPF
I know that this is late answer, maybe helpful for researchers
if (!WindowName.IsVisible)
{
WindowName.Show();
WindowName.Activate();
}
Change line width of lines in matplotlib pyplot legend
@ImportanceOfBeingErnest 's answer is good if you only want to change the linewidth inside the legend box. But I think it is a bit more complex since you have to copy the handles before changing legend linewidth. Besides, it can not change the legend label fontsize. The following two methods can not only change the linewidth but also the legend label text font size in a more concise way.
Method 1
import numpy as np
import matplotlib.pyplot as plt
# make some data
x = np.linspace(0, 2*np.pi)
y1 = np.sin(x)
y2 = np.cos(x)
# plot sin(x) and cos(x)
fig = plt.figure()
ax = fig.add_subplot(111)
ax.plot(x, y1, c='b', label='y1')
ax.plot(x, y2, c='r', label='y2')
leg = plt.legend()
# get the individual lines inside legend and set line width
for line in leg.get_lines():
line.set_linewidth(4)
# get label texts inside legend and set font size
for text in leg.get_texts():
text.set_fontsize('x-large')
plt.savefig('leg_example')
plt.show()
Method 2
import numpy as np
import matplotlib.pyplot as plt
# make some data
x = np.linspace(0, 2*np.pi)
y1 = np.sin(x)
y2 = np.cos(x)
# plot sin(x) and cos(x)
fig = plt.figure()
ax = fig.add_subplot(111)
ax.plot(x, y1, c='b', label='y1')
ax.plot(x, y2, c='r', label='y2')
leg = plt.legend()
# get the lines and texts inside legend box
leg_lines = leg.get_lines()
leg_texts = leg.get_texts()
# bulk-set the properties of all lines and texts
plt.setp(leg_lines, linewidth=4)
plt.setp(leg_texts, fontsize='x-large')
plt.savefig('leg_example')
plt.show()
The above two methods produce the same output image:
How do I resolve ClassNotFoundException?
Use ';' as the separator. If your environment variables are set correctly, you should see your settings. If your PATH and CLASSPATH is correct, windows should recognize those commands. You do NOT need to restart your computer when installing Java.
How to jump to top of browser page
You can set the scrollTop
, like this:
$('html,body').scrollTop(0);
Or if you want a little animation instead of a snap to the top:
$('html, body').animate({ scrollTop: 0 }, 'fast');
What exactly does += do in python?
Remember when you used to sum, for example 2 & 3, in your old calculator and every time you hit the =
you see 3 added to the total, the +=
does similar job. Example:
>>> orange = 2
>>> orange += 3
>>> print(orange)
5
>>> orange +=3
>>> print(orange)
8
Merge DLL into EXE?
I answered a similar question for VB.NET
. It shouldn't however be too hard to convert. You embedd the DLL's
into your Ressource
folder and on the first usage, the
AppDomain.CurrentDomain.AssemblyResolve
event gets fired.
If you want to reference it during development, just add a normal DLL
reference to your project.
Embedd a DLL into a project
How to select the nth row in a SQL database table?
PostgreSQL supports windowing functions as defined by the SQL standard, but they're awkward, so most people use (the non-standard) LIMIT
/ OFFSET
:
SELECT
*
FROM
mytable
ORDER BY
somefield
LIMIT 1 OFFSET 20;
This example selects the 21st row. OFFSET 20
is telling Postgres to skip the first 20 records. If you don't specify an ORDER BY
clause, there's no guarantee which record you will get back, which is rarely useful.
Send JSON via POST in C# and Receive the JSON returned?
Using the JSON.NET NuGet package and anonymous types, you can simplify what the other posters are suggesting:
// ...
string payload = JsonConvert.SerializeObject(new
{
agent = new
{
name = "Agent Name",
version = 1,
},
username = "username",
password = "password",
token = "xxxxx",
});
var client = new HttpClient();
var content = new StringContent(payload, Encoding.UTF8, "application/json");
HttpResponseMessage response = await client.PostAsync(uri, content);
// ...
Stopword removal with NLTK
You can use string.punctuation with built-in NLTK stopwords list:
from nltk.tokenize import word_tokenize, sent_tokenize
from nltk.corpus import stopwords
from string import punctuation
words = tokenize(text)
wordsWOStopwords = removeStopWords(words)
def tokenize(text):
sents = sent_tokenize(text)
return [word_tokenize(sent) for sent in sents]
def removeStopWords(words):
customStopWords = set(stopwords.words('english')+list(punctuation))
return [word for word in words if word not in customStopWords]
NLTK stopwords complete list
ojdbc14.jar vs. ojdbc6.jar
I have same problem!
Found following in oracle site
link text
As mentioned above, the 11.1 drivers by default convert SQL DATE to Timestamp when reading from the database. This always was the right thing to do and the change in 9i was a mistake. The 11.1 drivers have reverted to the correct behavior. Even if you didn't set V8Compatible in your application you shouldn't see any difference in behavior in most cases. You may notice a difference if you use getObject to read a DATE column. The result will be a Timestamp rather than a Date. Since Timestamp is a subclass of Date this generally isn't a problem. Where you might notice a difference is if you relied on the conversion from DATE to Date to truncate the time component or if you do toString on the value. Otherwise the change should be transparent.
If for some reason your app is very sensitive to this change and you simply must have the 9i-10g behavior, there is a connection property you can set. Set mapDateToTimestamp to false and the driver will revert to the default 9i-10g behavior and map DATE to Date.
HTML5 form validation pattern alphanumeric with spaces?
It's quite an old question, but in case it could be useful for anyone, starting from a combination of good responses found here, I've ended using this pattern:
pattern="([^\s][A-z0-9À-ž\s]+)"
It will require at least two characters, making sure it does not start with an empty space but allowing spaces between words, and also allowing special characters such as a, ó, ä, ö
.
Usage of the backtick character (`) in JavaScript
You can make a template of templates too, and reach private variable.
var a= {e:10, gy:'sfdsad'}; //global object
console.log(`e is ${a.e} and gy is ${a.gy}`);
//e is 10 and gy is sfdsad
var b = "e is ${a.e} and gy is ${a.gy}" // template string
console.log( `${b}` );
//e is ${a.e} and gy is ${a.gy}
console.log( eval(`\`${b}\``) ); // convert template string to template
//e is 10 and gy is sfdsad
backtick( b ); // use fonction's variable
//e is 20 and gy is fghj
function backtick( temp ) {
var a= {e:20, gy:'fghj'}; // local object
console.log( eval(`\`${temp}\``) );
}
Creating a blocking Queue<T> in .NET?
That looks very unsafe (very little synchronization); how about something like:
class SizeQueue<T>
{
private readonly Queue<T> queue = new Queue<T>();
private readonly int maxSize;
public SizeQueue(int maxSize) { this.maxSize = maxSize; }
public void Enqueue(T item)
{
lock (queue)
{
while (queue.Count >= maxSize)
{
Monitor.Wait(queue);
}
queue.Enqueue(item);
if (queue.Count == 1)
{
// wake up any blocked dequeue
Monitor.PulseAll(queue);
}
}
}
public T Dequeue()
{
lock (queue)
{
while (queue.Count == 0)
{
Monitor.Wait(queue);
}
T item = queue.Dequeue();
if (queue.Count == maxSize - 1)
{
// wake up any blocked enqueue
Monitor.PulseAll(queue);
}
return item;
}
}
}
(edit)
In reality, you'd want a way to close the queue so that readers start exiting cleanly - perhaps something like a bool flag - if set, an empty queue just returns (rather than blocking):
bool closing;
public void Close()
{
lock(queue)
{
closing = true;
Monitor.PulseAll(queue);
}
}
public bool TryDequeue(out T value)
{
lock (queue)
{
while (queue.Count == 0)
{
if (closing)
{
value = default(T);
return false;
}
Monitor.Wait(queue);
}
value = queue.Dequeue();
if (queue.Count == maxSize - 1)
{
// wake up any blocked enqueue
Monitor.PulseAll(queue);
}
return true;
}
}
PHPMyAdmin Default login password
I just installed Fedora 16 (yea, I know it's old and not supported but, I had the CD burnt :) )
Anyway, coming to the solution, this is what I was required to do:
su -
gedit /etc/phpMyAdmin/config.inc.php
if not found... try phpmyadmin - all small caps.
gedit /etc/phpmyadmin/config.inc.php
Locate
$cfg['Servers'][$i]['AllowNoPassword']
and set it to:
$cfg['Servers'][$i]['AllowNoPassword'] = TRUE;
Save it.
error: request for member '..' in '..' which is of non-class type
I was having a similar error, it seems that the compiler misunderstand the call to the constructor without arguments. I made it work by removing the parenthesis from the variable declaration, in your code something like this:
class Foo
{
public:
Foo() {};
Foo(int a) {};
void bar() {};
};
int main()
{
// this works...
Foo foo1(1);
foo1.bar();
// this does not...
Foo foo2; // Without "()"
foo2.bar();
return 0;
}
HTML table with fixed headers and a fixed column?
I have created something which has fixed header, fixed footer, fixed left column and also fixed right column. This only works fine in IE. As most of the users are still using IE this can be helpful. Please find the code here in Scrollable Table. Please let me your suggestions.
Meanwhile I am working to fix columns in other browser. I will keep you posted. :-)
ASP.NET MVC - Set custom IIdentity or IPrincipal
As an addition to LukeP code for Web Forms users (not MVC) if you want to simplify the access in the code behind of your pages, just add the code below to a base page and derive the base page in all your pages:
Public Overridable Shadows ReadOnly Property User() As CustomPrincipal
Get
Return DirectCast(MyBase.User, CustomPrincipal)
End Get
End Property
So in your code behind you can simply access:
User.FirstName or User.LastName
What I'm missing in a Web Form scenario, is how to obtain the same behaviour in code not tied to the page, for example in httpmodules should I always add a cast in each class or is there a smarter way to obtain this?
Thanks for your answers and thank to LukeP since I used your examples as a base for my custom user (which now has User.Roles
, User.Tasks
, User.HasPath(int)
, User.Settings.Timeout
and many other nice things)
Get UserDetails object from Security Context in Spring MVC controller
If you just want to print user name on the pages, maybe you'll like this solution. It's free from object castings and works without Spring Security too:
@RequestMapping(value = "/index.html", method = RequestMethod.GET)
public ModelAndView indexView(HttpServletRequest request) {
ModelAndView mv = new ModelAndView("index");
String userName = "not logged in"; // Any default user name
Principal principal = request.getUserPrincipal();
if (principal != null) {
userName = principal.getName();
}
mv.addObject("username", userName);
// By adding a little code (same way) you can check if user has any
// roles you need, for example:
boolean fAdmin = request.isUserInRole("ROLE_ADMIN");
mv.addObject("isAdmin", fAdmin);
return mv;
}
Note "HttpServletRequest request" parameter added.
Works fine because Spring injects it's own objects (wrappers) for HttpServletRequest, Principal etc., so you can use standard java methods to retrieve user information.
What is the size limit of a post request?
As David pointed out, I would go with KB in most cases.
php_value post_max_size 2K
Note: my form is simple, just a few text boxes, not long text.
(PHP shorthand for KB is K, as outlined here.)
Best way to check if a Data Table has a null value in it
You can loop throw the rows and columns, checking for nulls, keeping track of whether there's a null with a bool, then check it after looping through the table and handle it.
//your DataTable, replace with table get code
DataTable table = new DataTable();
bool tableHasNull = false;
foreach (DataRow row in table.Rows)
{
foreach (DataColumn col in table.Columns)
{
//test for null here
if (row[col] == DBNull.Value)
{
tableHasNull = true;
}
}
}
if (tableHasNull)
{
//handle null in table
}
You can also come out of the foreach loop with a break statement e.g.
//test for null here
if (row[col] == DBNull.Value)
{
tableHasNull = true;
break;
}
To save looping through the rest of the table.
Why would you use String.Equals over ==?
There is one subtle but very important difference between == and the String.Equals methods:
class Program
{
static void Main(string[] args)
{
CheckEquality("a", "a");
Console.WriteLine("----------");
CheckEquality("a", "ba".Substring(1));
}
static void CheckEquality<T>(T value1, T value2) where T : class
{
Console.WriteLine("value1: {0}", value1);
Console.WriteLine("value2: {0}", value2);
Console.WriteLine("value1 == value2: {0}", value1 == value2);
Console.WriteLine("value1.Equals(value2): {0}", value1.Equals(value2));
if (typeof(T).IsEquivalentTo(typeof(string)))
{
string string1 = (string)(object)value1;
string string2 = (string)(object)value2;
Console.WriteLine("string1 == string2: {0}", string1 == string2);
}
}
}
Produces this output:
value1: a
value2: a
value1 == value2: True
value1.Equals(value2): True
string1 == string2: True
----------
value1: a
value2: a
value1 == value2: False
value1.Equals(value2): True
string1 == string2: True
You can see that the == operator is returning false to two obviously equal strings. Why? Because the == operator in use in the generic method is resolved to be the op_equal method as defined by System.Object (the only guarantee of T the method has at compile time), which means that it's reference equality instead of value equality.
When you have two values typed as System.String explicitly, then == has a value-equality semantic because the compiler resolves the == to System.String.op_equal instead of System.Object.op_equal.
So to play it safe, I almost always use String.Equals instead to that I always get the value equality semantics I want.
And to avoid NullReferenceExceptions if one of the values is null, I always use the static String.Equals method:
bool true = String.Equals("a", "ba".Substring(1));
How can I represent an infinite number in Python?
No one seems to have mentioned about the negative infinity explicitly, so I think I should add it.
For negative infinity:
-math.inf
For positive infinity (just for the sake of completeness):
math.inf
onchange event for input type="number"
The oninput
event (.bind('input', fn)
) covers any changes from keystrokes to arrow clicks and keyboard/mouse paste, but is not supported in IE <9.
_x000D_
_x000D_
jQuery(function($) {_x000D_
$('#mirror').text($('#alice').val());_x000D_
_x000D_
$('#alice').on('input', function() {_x000D_
$('#mirror').text($('#alice').val());_x000D_
});_x000D_
});
_x000D_
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>_x000D_
_x000D_
<input id="alice" type="number" step="any" value="99">_x000D_
_x000D_
<p id="mirror"></p>
_x000D_
_x000D_
_x000D_
How to force DNS refresh for a website?
If both of your servers are using WHM, I think we can reduce the time to nil. Create your domain in the new server and set everything ready. Go to the previous server and delete the account corresponding to that domain. Until now I have got no errors by doing this and felt the update instantaneous. FYI I used hostgator hosting (both dedicated servers).
And I really dont know why it is so. It's supposed to be not like that until the TTL is over.
Java TreeMap Comparator
you can swipe the key and the value. For example
String[] k = {"Elena", "Thomas", "Hamilton", "Suzie", "Phil"};
int[] v = {341, 273, 278, 329, 445};
TreeMap<Integer,String>a=new TreeMap();
for (int i = 0; i < k.length; i++)
a.put(v[i],k[i]);
System.out.println(a.firstEntry().getValue()+"\t"+a.firstEntry().getKey());
a.remove(a.firstEntry().getKey());
System.out.println(a.firstEntry().getValue()+"\t"+a.firstEntry().getKey());
Difference in Months between two dates in JavaScript
I know this is really late, but posting it anyway just in case it helps others. Here is a function I came up with that seems to do a good job of counting differences in months between two dates. It is admittedly a great deal raunchier than Mr.Crowder's, but provides more accurate results by stepping through the date object. It is in AS3 but you should just be able to drop the strong typing and you'll have JS. Feel free to make it nicer looking anyone out there!
function countMonths ( startDate:Date, endDate:Date ):int
{
var stepDate:Date = new Date;
stepDate.time = startDate.time;
var monthCount:int;
while( stepDate.time <= endDate.time ) {
stepDate.month += 1;
monthCount += 1;
}
if ( stepDate != endDate ) {
monthCount -= 1;
}
return monthCount;
}
Split string into tokens and save them in an array
Why strtok()
is a bad idea
Do not use strtok()
in normal code, strtok()
uses static
variables which have some problems. There are some use cases on embedded microcontrollers where static
variables make sense but avoid them in most other cases. strtok()
behaves unexpected when more than 1 thread uses it, when it is used in a interrupt or when there are some other circumstances where more than one input is processed between successive calls to strtok()
.
Consider this example:
#include <stdio.h>
#include <string.h>
//Splits the input by the / character and prints the content in between
//the / character. The input string will be changed
void printContent(char *input)
{
char *p = strtok(input, "/");
while(p)
{
printf("%s, ",p);
p = strtok(NULL, "/");
}
}
int main(void)
{
char buffer[] = "abc/def/ghi:ABC/DEF/GHI";
char *p = strtok(buffer, ":");
while(p)
{
printContent(p);
puts(""); //print newline
p = strtok(NULL, ":");
}
return 0;
}
You may expect the output:
abc, def, ghi,
ABC, DEF, GHI,
But you will get
abc, def, ghi,
This is because you call strtok()
in printContent()
resting the internal state of strtok()
generated in main()
. After returning, the content of strtok()
is empty and the next call to strtok()
returns NULL
.
What you should do instead
You could use strtok_r()
when you use a POSIX system, this versions does not need static
variables. If your library does not provide strtok_r()
you can write your own version of it. This should not be hard and Stackoverflow is not a coding service, you can write it on your own.
How to scroll to the bottom of a RecyclerView? scrollToPosition doesn't work
Only Ian's answer was able to make my RecyclerView
scroll to a specified position. However, The RecyclerView
was not able to scroll afterwards when I used scrollToPosition()
. smoothScrollToPosition()
worked but the initial animation made it too slow when the list was long.
The reason was the listener was not removed. I used the code below to remove the current ViewTreeObserver
and it worked as a charm.
mRecyclerView.getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
@Override
public void onGlobalLayout() {
mRecyclerView.scrollToPosition(mPosition);
mRecyclerView.getViewTreeObserver().removeOnGlobalLayoutListener(this);
}
});
how to convert long date value to mm/dd/yyyy format
Refer below code for formatting date
long strDate1 = 1346524199000;
Date date=new Date(strDate1);
try {
SimpleDateFormat format = new SimpleDateFormat("EEE, dd MMM yyyy HH:mm:ss z");
SimpleDateFormat df2 = new SimpleDateFormat("dd/MM/yy");
date = df2.format(format.parse("yourdate");
} catch (java.text.ParseException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
Find TODO tags in Eclipse
Is there an easy way to view all methods which contain this comment? Some sort of menu option?
Yes, choose one of the following:
Go to Window ? Show View ? Tasks (Not TaskList). The new view will show up where the "Console" and "Problems" tabs are by default.
As mentioned elsewhere, you can see them next to the scroll bar as little blue rectangles if you have the source file in question open.
If you just want the // TODO Auto-generated method stub
messages (rather than all // TODO
messages) you should use the search function (Ctrl-F for ones in this file Search ? Java Search ? Search string for the ability to specify this workspace, that file, this project, etc.)
Two submit buttons in one form
You formaction for multiple submit button in one form
example
<input type="submit" name="" class="btn action_bg btn-sm loadGif" value="Add Address" title="" formaction="/addAddress">
<input type="submit" name="" class="btn action_bg btn-sm loadGif" value="update Address" title="" formaction="/updateAddress">
How to append a char to a std::string?
str.append(10u,'d'); //appends character d 10 times
Notice I have written 10u and not 10 for the number of times I'd like to append the character; replace 10 with whatever number.
Android: show/hide a view using an animation
I have used this two function to hide and show view with transition animation smoothly.
@TargetApi(Build.VERSION_CODES.HONEYCOMB)
public void expand(final View v, int duration, int targetHeight, final int position) {
int prevHeight = v.getHeight();
v.setVisibility(View.VISIBLE);
ValueAnimator valueAnimator = ValueAnimator.ofInt(0, targetHeight);
valueAnimator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
@Override
public void onAnimationUpdate(ValueAnimator animation) {
v.getLayoutParams().height = (int) animation.getAnimatedValue();
v.requestLayout();
}
});
valueAnimator.setInterpolator(new DecelerateInterpolator());
valueAnimator.setDuration(duration);
valueAnimator.start();
valueAnimator.addListener(new AnimatorListenerAdapter() {
@Override
public void onAnimationEnd(Animator animation) {
v.clearAnimation();
}
});
}
@TargetApi(Build.VERSION_CODES.HONEYCOMB)
public void collapse(final View v, int duration, int targetHeight, final int position) {
if (position == (data.size() - 1)) {
return;
}
int prevHeight = v.getHeight();
ValueAnimator valueAnimator = ValueAnimator.ofInt(prevHeight, targetHeight);
valueAnimator.setInterpolator(new DecelerateInterpolator());
valueAnimator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
@Override
public void onAnimationUpdate(ValueAnimator animation) {
v.getLayoutParams().height = (int) animation.getAnimatedValue();
v.requestLayout();
}
});
valueAnimator.setInterpolator(new DecelerateInterpolator());
valueAnimator.setDuration(duration);
valueAnimator.start();
valueAnimator.addListener(new AnimatorListenerAdapter() {
@Override
public void onAnimationEnd(Animator animation) {
animBoolArray.put(position, false);
v.clearAnimation();
}
});
}
AngularJS - Create a directive that uses ng-model
I took a combo of all answers, and now have two ways of doing this with the ng-model attribute:
- With a new scope which copies ngModel
- With the same scope which does a compile on link
_x000D_
_x000D_
var app = angular.module('model', []);_x000D_
_x000D_
app.controller('MainCtrl', function($scope) {_x000D_
$scope.name = "Felipe";_x000D_
$scope.label = "The Label";_x000D_
});_x000D_
_x000D_
app.directive('myDirectiveWithScope', function() {_x000D_
return {_x000D_
restrict: 'E',_x000D_
scope: {_x000D_
ngModel: '=',_x000D_
},_x000D_
// Notice how label isn't copied_x000D_
template: '<div class="some"><label>{{label}}: <input ng-model="ngModel"></label></div>',_x000D_
replace: true_x000D_
};_x000D_
});_x000D_
app.directive('myDirectiveWithChildScope', function($compile) {_x000D_
return {_x000D_
restrict: 'E',_x000D_
scope: true,_x000D_
// Notice how label is visible in the scope_x000D_
template: '<div class="some"><label>{{label}}: <input></label></div>',_x000D_
replace: true,_x000D_
link: function ($scope, element) {_x000D_
// element will be the div which gets the ng-model on the original directive_x000D_
var model = element.attr('ng-model');_x000D_
$('input',element).attr('ng-model', model);_x000D_
return $compile(element)($scope);_x000D_
}_x000D_
};_x000D_
});_x000D_
app.directive('myDirectiveWithoutScope', function($compile) {_x000D_
return {_x000D_
restrict: 'E',_x000D_
template: '<div class="some"><label>{{$parent.label}}: <input></label></div>',_x000D_
replace: true,_x000D_
link: function ($scope, element) {_x000D_
// element will be the div which gets the ng-model on the original directive_x000D_
var model = element.attr('ng-model');_x000D_
return $compile($('input',element).attr('ng-model', model))($scope);_x000D_
}_x000D_
};_x000D_
});_x000D_
app.directive('myReplacedDirectiveIsolate', function($compile) {_x000D_
return {_x000D_
restrict: 'E',_x000D_
scope: {},_x000D_
template: '<input class="some">',_x000D_
replace: true_x000D_
};_x000D_
});_x000D_
app.directive('myReplacedDirectiveChild', function($compile) {_x000D_
return {_x000D_
restrict: 'E',_x000D_
scope: true,_x000D_
template: '<input class="some">',_x000D_
replace: true_x000D_
};_x000D_
});_x000D_
app.directive('myReplacedDirective', function($compile) {_x000D_
return {_x000D_
restrict: 'E',_x000D_
template: '<input class="some">',_x000D_
replace: true_x000D_
};_x000D_
});
_x000D_
.some {_x000D_
border: 1px solid #cacaca;_x000D_
padding: 10px;_x000D_
}
_x000D_
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>_x000D_
<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.2.0/angular.min.js"></script>_x000D_
<div ng-app="model" ng-controller="MainCtrl">_x000D_
This scope value <input ng-model="name">, label: "{{label}}"_x000D_
<ul>_x000D_
<li>With new isolate scope (label from parent):_x000D_
<my-directive-with-scope ng-model="name"></my-directive-with-scope>_x000D_
</li>_x000D_
<li>With new child scope:_x000D_
<my-directive-with-child-scope ng-model="name"></my-directive-with-child-scope>_x000D_
</li>_x000D_
<li>Same scope:_x000D_
<my-directive-without-scope ng-model="name"></my-directive-without-scope>_x000D_
</li>_x000D_
<li>Replaced element, isolate scope:_x000D_
<my-replaced-directive-isolate ng-model="name"></my-replaced-directive-isolate>_x000D_
</li>_x000D_
<li>Replaced element, child scope:_x000D_
<my-replaced-directive-child ng-model="name"></my-replaced-directive-child>_x000D_
</li>_x000D_
<li>Replaced element, same scope:_x000D_
<my-replaced-directive ng-model="name"></my-replaced-directive>_x000D_
</li>_x000D_
</ul>_x000D_
<p>Try typing in the child scope ones, they copy the value into the child scope which breaks the link with the parent scope._x000D_
<p>Also notice how removing jQuery makes it so only the new-isolate-scope version works._x000D_
<p>Finally, note that the replace+isolate scope only works in AngularJS >=1.2.0_x000D_
</div>
_x000D_
_x000D_
_x000D_
I'm not sure I like the compiling at link time. However, if you're just replacing the element with another you don't need to do that.
All in all I prefer the first one. Simply set scope to {ngModel:"="}
and set ng-model="ngModel"
where you want it in your template.
Update: I inlined the code snippet and updated it for Angular v1.2. Turns out that isolate scope is still best, especially when not using jQuery. So it boils down to:
Are you replacing a single element: Just replace it, leave the scope alone, but note that replace is deprecated for v2.0:
app.directive('myReplacedDirective', function($compile) {
return {
restrict: 'E',
template: '<input class="some">',
replace: true
};
});
Otherwise use this:
app.directive('myDirectiveWithScope', function() {
return {
restrict: 'E',
scope: {
ngModel: '=',
},
template: '<div class="some"><input ng-model="ngModel"></div>'
};
});
Set an environment variable in git bash
Creating a .bashrc file in your home directory also works. That way you don't have to copy your .bash_profile every time you install a new version of git bash.
How to compile for Windows on Linux with gcc/g++?
Install a cross compiler, like mingw64 from your package manager.
Then compile in the following way: instead of simply calling gcc
call i686-w64-mingw32-gcc
for 32-bit Windows or x86_64-w64-mingw32-gcc"
for 64-bit Windows. I would also use the --static
option, as the target system may not have all the libraries.
If you want to compile other language, like Fortran, replace -gcc
with -gfortran
in the previous commands.
final keyword in method parameters
Strings are immutable, so actully you can't change the String afterwards (you can only make the variable that held the String object point to a different String object).
However, that is not the reason why you can bind any variable to a final
parameter. All the compiler checks is that the parameter is not reassigned within the method. This is good for documentation purposes, arguably good style, and may even help optimize the byte code for speed (although this seems not to do very much in practice).
But even if you do reassign a parameter within a method, the caller doesn't notice that, because java does all parameter passing by value. After the sequence
a = someObject();
process(a);
the fields of a may have changed, but a is still the same object it was before. In pass-by-reference languages this may not be true.
How to pass dictionary items as function arguments in python?
If you want to use them like that, define the function with the variable names as normal:
def my_function(school, standard, city, name):
schoolName = school
cityName = city
standardName = standard
studentName = name
Now you can use **
when you call the function:
data = {'school':'DAV', 'standard': '7', 'name': 'abc', 'city': 'delhi'}
my_function(**data)
and it will work as you want.
P.S. Don't use reserved words such as class
.(e.g., use klass
instead)
How do I use reflection to call a generic method?
You need to use reflection to get the method to start with, then "construct" it by supplying type arguments with MakeGenericMethod:
MethodInfo method = typeof(Sample).GetMethod(nameof(Sample.GenericMethod));
MethodInfo generic = method.MakeGenericMethod(myType);
generic.Invoke(this, null);
For a static method, pass null
as the first argument to Invoke
. That's nothing to do with generic methods - it's just normal reflection.
As noted, a lot of this is simpler as of C# 4 using dynamic
- if you can use type inference, of course. It doesn't help in cases where type inference isn't available, such as the exact example in the question.
Nginx 403 forbidden for all files
I solved this problem by adding user settings.
in nginx.conf
worker_processes 4;
user username;
change the 'username' with linux user name.
How to change MySQL column definition?
Do you mean altering the table after it has been created? If so you need to use alter table, in particular:
ALTER TABLE tablename MODIFY COLUMN new-column-definition
e.g.
ALTER TABLE test MODIFY COLUMN locationExpect VARCHAR(120);
What is Teredo Tunneling Pseudo-Interface?
Unless you have some kind of really weird problem, keep it. The number of IPv6 sites is very small, but there are some and it will let you get to them even if you're at an IPv4 only location.
If it is causing you a problem, it's best to fix it. I've seen a number of people recommending removing it to solve problems. However, they're not actually solving the root cause of the issue. In all the cases I've seen, removing Teredo just happens to cause a side-effect that fixes their problem... :)
sass :first-child not working
While @Andre is correct that there are issues with pseudo elements and their support, especially in older (IE) browsers, that support is improving all the time.
As for your question of, are there any issues, I'd say I've not really seen any, although the syntax for the pseudo-element can be a bit tricky, especially when first sussing it out. So:
div#top-level
declarations: ...
div.inside
declarations: ...
&:first-child
declarations: ...
which compiles as one would expect:
div#top-level{
declarations... }
div#top-level div.inside {
declarations... }
div#top-level div.inside:first-child {
declarations... }
I haven't seen any documentation on any of this, save for the statement that "sass can do everything that css can do." As always, with Haml and SASS the indentation is everything.
CSS, Images, JS not loading in IIS
For me adding this in the web.config
resolved the problem
<system.webServer>
<modules runAllManagedModulesForAllRequests="true" >
<remove name="UrlRoutingModule"/>
</modules>
</system.webServer>
Returning binary file from controller in ASP.NET Web API
Try using a simple HttpResponseMessage
with its Content
property set to a StreamContent
:
// using System.IO;
// using System.Net.Http;
// using System.Net.Http.Headers;
public HttpResponseMessage Post(string version, string environment,
string filetype)
{
var path = @"C:\Temp\test.exe";
HttpResponseMessage result = new HttpResponseMessage(HttpStatusCode.OK);
var stream = new FileStream(path, FileMode.Open, FileAccess.Read);
result.Content = new StreamContent(stream);
result.Content.Headers.ContentType =
new MediaTypeHeaderValue("application/octet-stream");
return result;
}
A few things to note about the stream
used:
You must not call stream.Dispose()
, since Web API still needs to be able to access it when it processes the controller method's result
to send data back to the client. Therefore, do not use a using (var stream = …)
block. Web API will dispose the stream for you.
Make sure that the stream has its current position set to 0 (i.e. the beginning of the stream's data). In the above example, this is a given since you've only just opened the file. However, in other scenarios (such as when you first write some binary data to a MemoryStream
), make sure to stream.Seek(0, SeekOrigin.Begin);
or set stream.Position = 0;
With file streams, explicitly specifying FileAccess.Read
permission can help prevent access rights issues on web servers; IIS application pool accounts are often given only read / list / execute access rights to the wwwroot.
How to check if a date is in a given range?
I found this method the easiest:
$start_date = '2009-06-17';
$end_date = '2009-09-05';
$date_from_user = '2009-08-28';
$start_date = date_create($start_date);
$date_from_user = date_create($date_from_user);
$end_date = date_create($end_date);
$interval1 = date_diff($start_date, $date_from_user);
$interval2 = date_diff($end_date, $date_from_user);
if($interval1->invert == 0){
if($interval2->invert == 1){
// if it lies between start date and end date execute this code
}
}
jquery - check length of input field?
That doesn't work because, judging by the rest of the code, the initial value of the text input is "Default text" - which is more than one character, and so your if
condition is always true.
The simplest way to make it work, it seems to me, is to account for this case:
var value = $(this).val();
if ( value.length > 0 && value != "Default text" ) ...
How to make a website secured with https
I think you are getting confused with your site Authentication and SSL.
If you need to get your site into SSL, then you would need to install a SSL certificate into your web server. You can buy a certificate for yourself from one of the places like Symantec etc. The certificate would contain your public/private key pair, along with other things.
You wont need to do anything in your source code, and you can still continue to use your Form Authntication (or any other) in your site. Its just that, any data communication that takes place between the web server and the client will encrypted and signed using your certificate. People would use secure-HTTP (https://) to access your site.
View this for more info --> http://en.wikipedia.org/wiki/Transport_Layer_Security
Objects inside objects in javascript
You may have as many levels of Object hierarchy as you want, as long you declare an Object as being a property of another parent Object. Pay attention to the commas on each level, that's the tricky part. Don't use commas after the last element on each level:
{el1, el2, {el31, el32, el33}, {el41, el42}}
_x000D_
_x000D_
var MainObj = {_x000D_
_x000D_
prop1: "prop1MainObj",_x000D_
_x000D_
Obj1: {_x000D_
prop1: "prop1Obj1",_x000D_
prop2: "prop2Obj1", _x000D_
Obj2: {_x000D_
prop1: "hey you",_x000D_
prop2: "prop2Obj2"_x000D_
}_x000D_
},_x000D_
_x000D_
Obj3: {_x000D_
prop1: "prop1Obj3",_x000D_
prop2: "prop2Obj3"_x000D_
},_x000D_
_x000D_
Obj4: {_x000D_
prop1: true,_x000D_
prop2: 3_x000D_
} _x000D_
};_x000D_
_x000D_
console.log(MainObj.Obj1.Obj2.prop1);
_x000D_
_x000D_
_x000D_
NullPointerException in eclipse in Eclipse itself at PartServiceImpl.internalFixContext
After exiting eclipse I moved .eclipse (found in the user's home directory) to .eclipse.old (just in case I may have had to undo). The error does not show up any more and my projects are working fine after restarting eclipse.
Caution: I have a simple setup and this may not be the best for environments with advanced settings.
I am posting this as a separate answer as previously listed methods did not work for me.
Web Reference vs. Service Reference
Adding a service reference allows you to create a WCF client, which can be used to talk to a regular web service provided you use the appropriate binding. Adding a web reference will allow you to create only a web service (i.e., SOAP) reference.
If you are absolutely certain you are not ready for WCF (really don't know why) then you should create a regular web service reference.
What's the difference between "Write-Host", "Write-Output", or "[console]::WriteLine"?
Write-Output
should be used when you want to send data on in the pipe line, but not necessarily want to display it on screen. The pipeline will eventually write it to out-default
if nothing else uses it first.
Write-Host
should be used when you want to do the opposite.
[console]::WriteLine
is essentially what Write-Host
is doing behind the scenes.
Run this demonstration code and examine the result.
function Test-Output {
Write-Output "Hello World"
}
function Test-Output2 {
Write-Host "Hello World" -foreground Green
}
function Receive-Output {
process { Write-Host $_ -foreground Yellow }
}
#Output piped to another function, not displayed in first.
Test-Output | Receive-Output
#Output not piped to 2nd function, only displayed in first.
Test-Output2 | Receive-Output
#Pipeline sends to Out-Default at the end.
Test-Output
You'll need to enclose the concatenation operation in parentheses, so that PowerShell processes the concatenation before tokenizing the parameter list for Write-Host
, or use string interpolation
write-host ("count=" + $count)
# or
write-host "count=$count"
BTW - Watch this video of Jeffrey Snover explaining how the pipeline works. Back when I started learning PowerShell I found this to be the most useful explanation of how the pipeline works.
Find an element in a list of tuples
Or takewhile
, ( addition to this, example of more values is shown ):
>>> a= [(1,2),(1,4),(3,5),(5,7),(0,2)]
>>> import itertools
>>> list(itertools.takewhile(lambda x: x[0]==1,a))
[(1, 2), (1, 4)]
>>>
if unsorted, like:
>>> a= [(1,2),(3,5),(1,4),(5,7)]
>>> import itertools
>>> list(itertools.takewhile(lambda x: x[0]==1,sorted(a,key=lambda x: x[0]==1)))
[(1, 2), (1, 4)]
>>>
Using an integer as a key in an associative array in JavaScript
Get the value for an associative array property when the property name is an integer:
Starting with an associative array where the property names are integers:
var categories = [
{"1": "Category 1"},
{"2": "Category 2"},
{"3": "Category 3"},
{"4": "Category 4"}
];
Push items to the array:
categories.push({"2300": "Category 2300"});
categories.push({"2301": "Category 2301"});
Loop through the array and do something with the property value.
for (var i = 0; i < categories.length; i++) {
for (var categoryid in categories[i]) {
var category = categories[i][categoryid];
// Log progress to the console
console.log(categoryid + ": " + category);
// ... do something
}
}
Console output should look like this:
1: Category 1
2: Category 2
3: Category 3
4: Category 4
2300: Category 2300
2301: Category 2301
As you can see, you can get around the associative array limitation and have a property name be an integer.
NOTE: The associative array in my example is the JSON content you would have if you serialized a Dictionary<string, string>[] object.
Difference between partition key, composite key and clustering key in Cassandra?
Adding a summary answer as the accepted one is quite long. The terms "row" and "column" are used in the context of CQL, not how Cassandra is actually implemented.
- A primary key uniquely identifies a row.
- A composite key is a key formed from multiple columns.
- A partition key is the primary lookup to find a set of rows, i.e. a partition.
- A clustering key is the part of the primary key that isn't the partition key (and defines the ordering within a partition).
Examples:
PRIMARY KEY (a)
: The partition key is a
.
PRIMARY KEY (a, b)
: The partition key is a
, the clustering key is b
.
PRIMARY KEY ((a, b))
: The composite partition key is (a, b)
.
PRIMARY KEY (a, b, c)
: The partition key is a
, the composite clustering key is (b, c)
.
PRIMARY KEY ((a, b), c)
: The composite partition key is (a, b)
, the clustering key is c
.
PRIMARY KEY ((a, b), c, d)
: The composite partition key is (a, b)
, the composite clustering key is (c, d)
.
How to write a full path in a batch file having a folder name with space?
I made a **
automatic-network-drive connector
** using a batch file.
Suddenly there was a networkdrive called "Data for Analysation", and yeah with the double quotes it works proper!
looks a little bit different but works:
net use y: "\\share.blabla.com\Folder\Subfolder\Data for Analysation" /USER:domain\username PW /PERSISTENT:YES
Thx for the Hint :)
Git commit with no commit message
You don't need git to accomplish this. Creative use of a bash function will do the trick just fine. If you don't care about messages, just set a default one and forget it.
function gitcom() {
git commit -m "my default commit message"
}
If you were feeling really adventurous you could add, commit and push with one command
function gitzap() {
git add . && git commit -m "whatevs" && git push $1 $2
}
Which you would then run as
gitzap origin master
You could even get deeper and use parse_git_branch to save yourself some keystrokes there, or set a common default of "origin" and "master".
How can I check if a string only contains letters in Python?
You can leverage regular expressions.
>>> import re
>>> pattern = re.compile("^[a-zA-Z]+$")
>>> pattern.match("hello")
<_sre.SRE_Match object; span=(0, 5), match='hello'>
>>> pattern.match("hel7lo")
>>>
The match()
method will return a Match
object if a match is found. Otherwise it will return None
.
An easier approach is to use the .isalpha()
method
>>> "Hello".isalpha()
True
>>> "Hel7lo".isalpha()
False
isalpha()
returns true if there is at least 1 character in the string and if all the characters in the string are alphabets.
AngularJS Dropdown required validation
You need to add a name
attribute to your dropdown list, then you need to add a required
attribute, and then you can reference the error using myForm.[input name].$error.required
:
HTML:
<form name="myForm" ng-controller="Ctrl" ng-submit="save(myForm)" novalidate>
<input type="text" name="txtServiceName" ng-model="ServiceName" required>
<span ng-show="myForm.txtServiceName.$error.required">Enter Service Name</span>
<br/>
<select name="service_id" class="Sitedropdown" style="width: 220px;"
ng-model="ServiceID"
ng-options="service.ServiceID as service.ServiceName for service in services"
required>
<option value="">Select Service</option>
</select>
<span ng-show="myForm.service_id.$error.required">Select service</span>
</form>
Controller:
function Ctrl($scope) {
$scope.services = [
{ServiceID: 1, ServiceName: 'Service1'},
{ServiceID: 2, ServiceName: 'Service2'},
{ServiceID: 3, ServiceName: 'Service3'}
];
$scope.save = function(myForm) {
console.log('Selected Value: '+ myForm.service_id.$modelValue);
alert('Data Saved! without validate');
};
}
Here's a working plunker.
Difference between Build Solution, Rebuild Solution, and Clean Solution in Visual Studio?
Build Solution - Builds any assemblies which have changed files. If an assembly has no changes, it won't be re-built. Also will not delete any intermediate files.
Used most commonly.
Rebuild Solution - Rebuilds all assemblies regardless of changes but leaves intermediate files.
Used when you notice that Visual Studio didn't incorporate your changes in the latest assembly. Sometimes Visual Studio does make mistakes.
Clean Solution - Delete all intermediate files.
Used when all else fails and you need to clean everything up and start fresh.
Convert String to Float in Swift
You have two options which are quite similar (by the approach and result):
// option 1:
var string_1 : String = "100"
var double_1 : Double = (string_1 as NSString).doubleValue + 99.0
// option 2:
var string_2 : NSString = "100"
// or: var string_2 = "100" as NSString
var number_2 : Double = string_2.doubleValue;
Downloading images with node.js
Building on the above, if anyone needs to handle errors in the write/read streams, I used this version. Note the stream.read()
in case of a write error, it's required so we can finish reading and trigger close
on the read stream.
var download = function(uri, filename, callback){
request.head(uri, function(err, res, body){
if (err) callback(err, filename);
else {
var stream = request(uri);
stream.pipe(
fs.createWriteStream(filename)
.on('error', function(err){
callback(error, filename);
stream.read();
})
)
.on('close', function() {
callback(null, filename);
});
}
});
};
How can I change Eclipse theme?
Take a look at rogerdudler/eclipse-ui-themes . In the readme there is a link to a file that you need to extract into your eclipse/dropins
folder.
When you have done that go to
Window -> Preferences -> General -> Appearance
And change the theme from GTK (or what ever it is currently) to Dark Juno
(or Dark).
That will change the UI to a nice dark theme but to get the complete look and feel you can get the Eclipse Color Theme plugin from eclipsecolorthemes.org. The easiest way is to add this update URI to "Help -> Install New Software" and install it from there.
Eclipse Color Themes
This adds a "Color Theme" menu item under
Window -> Preferences -> Appearance
Where you can select from a large range of editor themes. My preferred one to use with PyDev is Wombat. For Java Solarized Dark
Docker compose, running containers in net:host
Maybe I am answering very late. But I was also having a problem configuring host network in docker compose. Then I read the documentation thoroughly and made the changes and it worked. Please note this configuration is for docker-compose version "3.7". Here einwohner_net and elk_net_net are my user-defined networks required for my application. I am using host net to get some system metrics.
Link To Documentation https://docs.docker.com/compose/compose-file/#host-or-none
version: '3.7'
services:
app:
image: ramansharma/einwohnertomcat:v0.0.1
deploy:
replicas: 1
ports:
- '8080:8080'
volumes:
- type: bind
source: /proc
target: /hostfs/proc
read_only: true
- type: bind
source: /sys/fs/cgroup
target: /hostfs/sys/fs/cgroup
read_only: true
- type: bind
source: /
target: /hostfs
read_only: true
networks:
hostnet: {}
networks:
- einwohner_net
- elk_elk_net
networks:
einwohner_net:
elk_elk_net:
external: true
hostnet:
external: true
name: host
How to change the scrollbar color using css
Your css will only work in IE browser. And the css suggessted by hayk.mart will olny work in webkit browsers. And by using different css hacks you can't style your browsers scroll bars with a same result.
So, it is better to use a jQuery/Javascript plugin to achieve a cross browser solution with a same result.
Solution:
By Using jScrollPane a jQuery plugin, you can achieve a cross browser solution
See This Demo
Check if a file exists with wildcard in shell script
Using new fancy shmancy features in ksh, bash, and zsh shells (this example doesn't handle spaces in filenames):
# Declare a regular array (-A will declare an associative array. Kewl!)
declare -a myarray=( /mydir/tmp*.txt )
array_length=${#myarray[@]}
# Not found if the 1st element of the array is the unexpanded string
# (ie, if it contains a "*")
if [[ ${myarray[0]} =~ [*] ]] ; then
echo "No files not found"
elif [ $array_length -eq 1 ] ; then
echo "File was found"
else
echo "Files were found"
fi
for myfile in ${myarray[@]}
do
echo "$myfile"
done
Yes, this does smell like Perl. Glad I didn't step in it ;)
Iterate over the lines of a string
Here are three possibilities:
foo = """
this is
a multi-line string.
"""
def f1(foo=foo): return iter(foo.splitlines())
def f2(foo=foo):
retval = ''
for char in foo:
retval += char if not char == '\n' else ''
if char == '\n':
yield retval
retval = ''
if retval:
yield retval
def f3(foo=foo):
prevnl = -1
while True:
nextnl = foo.find('\n', prevnl + 1)
if nextnl < 0: break
yield foo[prevnl + 1:nextnl]
prevnl = nextnl
if __name__ == '__main__':
for f in f1, f2, f3:
print list(f())
Running this as the main script confirms the three functions are equivalent. With timeit
(and a * 100
for foo
to get substantial strings for more precise measurement):
$ python -mtimeit -s'import asp' 'list(asp.f3())'
1000 loops, best of 3: 370 usec per loop
$ python -mtimeit -s'import asp' 'list(asp.f2())'
1000 loops, best of 3: 1.36 msec per loop
$ python -mtimeit -s'import asp' 'list(asp.f1())'
10000 loops, best of 3: 61.5 usec per loop
Note we need the list()
call to ensure the iterators are traversed, not just built.
IOW, the naive implementation is so much faster it isn't even funny: 6 times faster than my attempt with find
calls, which in turn is 4 times faster than a lower-level approach.
Lessons to retain: measurement is always a good thing (but must be accurate); string methods like splitlines
are implemented in very fast ways; putting strings together by programming at a very low level (esp. by loops of +=
of very small pieces) can be quite slow.
Edit: added @Jacob's proposal, slightly modified to give the same results as the others (trailing blanks on a line are kept), i.e.:
from cStringIO import StringIO
def f4(foo=foo):
stri = StringIO(foo)
while True:
nl = stri.readline()
if nl != '':
yield nl.strip('\n')
else:
raise StopIteration
Measuring gives:
$ python -mtimeit -s'import asp' 'list(asp.f4())'
1000 loops, best of 3: 406 usec per loop
not quite as good as the .find
based approach -- still, worth keeping in mind because it might be less prone to small off-by-one bugs (any loop where you see occurrences of +1 and -1, like my f3
above, should automatically trigger off-by-one suspicions -- and so should many loops which lack such tweaks and should have them -- though I believe my code is also right since I was able to check its output with other functions').
But the split-based approach still rules.
An aside: possibly better style for f4
would be:
from cStringIO import StringIO
def f4(foo=foo):
stri = StringIO(foo)
while True:
nl = stri.readline()
if nl == '': break
yield nl.strip('\n')
at least, it's a bit less verbose. The need to strip trailing \n
s unfortunately prohibits the clearer and faster replacement of the while
loop with return iter(stri)
(the iter
part whereof is redundant in modern versions of Python, I believe since 2.3 or 2.4, but it's also innocuous). Maybe worth trying, also:
return itertools.imap(lambda s: s.strip('\n'), stri)
or variations thereof -- but I'm stopping here since it's pretty much a theoretical exercise wrt the strip
based, simplest and fastest, one.
How to calculate difference between two dates in oracle 11g SQL
You can use this:
SET FEEDBACK OFF;
SET SERVEROUTPUT ON;
DECLARE
V_START_DATE CHAR(17) := '28/03/16 17:20:00';
V_END_DATE CHAR(17) := '30/03/16 17:50:10';
V_DATE_DIFF VARCHAR2(17);
BEGIN
SELECT
(TO_NUMBER( SUBSTR(NUMTODSINTERVAL(TO_DATE(V_END_DATE , 'DD/MM/YY HH24:MI:SS') - TO_DATE(V_START_DATE, 'DD/MM/YY HH24:MI:SS'), 'DAY'), 02, 9)) * 24) +
(TO_NUMBER( SUBSTR(NUMTODSINTERVAL(TO_DATE(V_END_DATE , 'DD/MM/YY HH24:MI:SS') - TO_DATE(V_START_DATE, 'DD/MM/YY HH24:MI:SS'), 'DAY'), 12, 2))) ||
SUBSTR(NUMTODSINTERVAL(TO_DATE(V_END_DATE , 'DD/MM/YY HH24:MI:SS') - TO_DATE(V_START_DATE, 'DD/MM/YY HH24:MI:SS'), 'DAY'), 14, 6) AS "HH24:MI:SS"
INTO V_DATE_DIFF
FROM
DUAL;
DBMS_OUTPUT.PUT_LINE(V_DATE_DIFF);
END;
Under which circumstances textAlign property works in Flutter?
You can align text anywhere in the scaffold or container except center:-
Its works for me anywhere in my application:-
new Text(
"Nextperience",
//i have setted in center.
textAlign: TextAlign.center,
//when i want it left.
//textAlign: TextAlign.left,
//when i want it right.
//textAlign: TextAlign.right,
style: TextStyle(
fontSize: 16,
color: Colors.blue[900],
fontWeight: FontWeight.w500),
),
how to solve Error cannot add duplicate collection entry of type add with unique key attribute 'value' in iis 7
IIS7 defines a defaultDocument section in its configuration files which can be found in the %WinDir%\System32\InetSrv\Config folder. Most likely, the file index.aspx is already defined as a default document in one of IIS7's configuration files and you are adding it again in your web.config.
I suspect that removing the line
<add value="index.aspx" />
from the defaultDocument/files section will fix your issue.
The defaultDocument section of your config will look like:
<defaultDocument>
<files>
<remove value="default.aspx" />
<remove value="index.html" />
<remove value="iisstart.htm" />
<remove value="index.htm" />
<remove value="Default.asp" />
<remove value="Default.htm" />
</files>
</defaultDocument>
Note that index.aspx will still appear in the list of default documents for your site in the IIS manager.
For more information about IIS7 configuration, click here.
Skip rows during csv import pandas
Also be sure that your file is actually a CSV file. For example, if you had an .xls file, and simply changed the file extension to .csv, the file won't import and will give the error above. To check to see if this is your problem open the file in excel and it will likely say:
"The file format and extension of 'Filename.csv' don't match. The file could be corrupted or unsafe. Unless you trust its source, don't open it. Do you want to open it anyway?"
To fix the file: open the file in Excel, click "Save As", Choose the file format to save as (use .cvs), then replace the existing file.
This was my problem, and fixed the error for me.
Change WPF window background image in C# code
I have been trying all the answers here with no success. Here is the simplest way to do it with ms-appx
ImageBrush myBrush = new ImageBrush();
Image image = new Image();
image.Source = new BitmapImage(new Uri(@"ms-appx:///Assets/background.jpg"));
myBrush.ImageSource = image.Source;
TheGrid.Background = myBrush;
Assets folder is in the first level of my project, so make sure to change the path as convenient.
ImportError: No module named scipy
I recommend you to remove scipy via
apt-get purge scipy
and then to install it by
pip install scipy
If you do both then you might confuse you deb package manager due to possibly differing versions.
Compile a DLL in C/C++, then call it from another program
Here is how you do it:
In .h
#ifdef BUILD_DLL
#define EXPORT __declspec(dllexport)
#else
#define EXPORT __declspec(dllimport)
#endif
extern "C" // Only if you are using C++ rather than C
{
EXPORT int __stdcall add2(int num);
EXPORT int __stdcall mult(int num1, int num2);
}
in .cpp
extern "C" // Only if you are using C++ rather than C
{
EXPORT int __stdcall add2(int num)
{
return num + 2;
}
EXPORT int __stdcall mult(int num1, int num2)
{
int product;
product = num1 * num2;
return product;
}
}
The macro tells your module (i.e your .cpp files) that they are providing the dll stuff to the outside world. People who incude your .h file want to import the same functions, so they sell EXPORT as telling the linker to import. You need to add BUILD_DLL to the project compile options, and you might want to rename it to something obviously specific to your project (in case a dll uses your dll).
You might also need to create a .def file to rename the functions and de-obfuscate the names (C/C++ mangles those names). This blog entry might be an interesting launching off point about that.
Loading your own custom dlls is just like loading system dlls. Just ensure that the DLL is on your system path. C:\windows\ or the working dir of your application are an easy place to put your dll.
How to recompile with -fPIC
Before compiling make sure that "rules.mk" file is included properly in Makefile or include it explicitly by:
"source rules.mk"
Return string without trailing slash
Based on @vdegenne 's answer... how to strip:
Single trailing slash:
theString.replace(/\/$/, '');
Single or consecutive trailing slashes:
theString.replace(/\/+$/g, '');
Single leading slash:
theString.replace(/^\//, '');
Single or consecutive leading slashes:
theString.replace(/^\/+/g, '');
Single leading and trailing slashes:
theString.replace(/^\/|\/$/g, '')
Single or consecutive leading and trailing slashes:
theString.replace(/^\/+|\/+$/g, '')
To handle both slashes and backslashes, replace instances of \/
with [\\/]
Add "Are you sure?" to my excel button, how can I?
Create a new sub with the following code and assign it to your button. Change the "DeleteProcess" to the name of your code to do the deletion. This will pop up a box with OK or Cancel and will call your delete sub if you hit ok and not if you hit cancel.
Sub AreYouSure()
Dim Sure As Integer
Sure = MsgBox("Are you sure?", vbOKCancel)
If Sure = 1 Then Call DeleteProcess
End Sub
Jesse
Editing the git commit message in GitHub
For intellij users:
If you want to make changes in interactive way for past commits, which are not pushed follow below steps in Intellij:
- Select Version Control
- Select Log
- Right click the commit for which you want to amend comment
- Click reword
- Done
Hope it helps
Get specific objects from ArrayList when objects were added anonymously?
I would suggest overriding the equals(Object)
of your Party
class. It might look something like this:
public boolean equals(Object o){
if(o == null)
return false;
if(o instanceof String)
return name.equalsIgnoreCase((String)o);
else if(o instanceof Party)
return equals(((Party)o).name);
return false;
}
After you do that, you could use the indexOf(Object)
method to retrieve the index of the party specified by its name, as shown below:
int index = cave.parties.indexOf("SecondParty");
Would return the index of the Party
with the name SecondParty
.
Note: This only works because you are overriding the equals(Object)
method.
What is HEAD in Git?
To quote other people:
A head is simply a reference to a
commit object. Each head has a name
(branch name or tag name, etc). By
default, there is a head in every
repository called master. A repository
can contain any number of heads. At
any given time, one head is selected
as the “current head.” This head is
aliased to HEAD, always in capitals".
Note this difference: a “head”
(lowercase) refers to any one of the
named heads in the repository; “HEAD”
(uppercase) refers exclusively to the
currently active head. This
distinction is used frequently in Git
documentation.
Another good source that quickly covers the inner workings of git (and therefor a better understanding of heads/HEAD) can be found here. References (ref:) or heads or branches can be considered like post-it notes stuck onto commits in the commit history. Usually they point to the tip of series of commits, but they can be moved around with git checkout
or git reset
etc.
How to use underscore.js as a template engine?
I am giving a very simple example
1)
var data = {site:"mysite",name:"john",age:25};
var template = "Welcome you are at <%=site %>.This has been created by <%=name %> whose age is <%=age%>";
var parsedTemplate = _.template(template,data);
console.log(parsedTemplate);
The result would be
Welcome you are at mysite.This has been created by john whose age is 25.
2) This is a template
<script type="text/template" id="template_1">
<% _.each(items,function(item,key,arr) { %>
<li>
<span><%= key %></span>
<span><%= item.name %></span>
<span><%= item.type %></span>
</li>
<% }); %>
</script>
This is html
<div>
<ul id="list_2"></ul>
</div>
This is the javascript code which contains json object and putting template into html
var items = [
{
name:"name1",
type:"type1"
},
{
name:"name1",
type:"type1"
},
{
name:"name1",
type:"type1"
},
{
name:"name1",
type:"type1"
},
{
name:"name1",
type:"type1"
}
];
$(document).ready(function(){
var template = $("#template_1").html();
$("#list_2").html(_.template(template,{items:items}));
});
java howto ArrayList push, pop, shift, and unshift
Great Answer by Jon.
I'm lazy though and I hate typing, so I created a simple cut and paste example for all the other people who are like me. Enjoy!
import java.util.ArrayList;
import java.util.List;
public class Main {
public static void main(String[] args) {
List<String> animals = new ArrayList<>();
animals.add("Lion");
animals.add("Tiger");
animals.add("Cat");
animals.add("Dog");
System.out.println(animals); // [Lion, Tiger, Cat, Dog]
// add() -> push(): Add items to the end of an array
animals.add("Elephant");
System.out.println(animals); // [Lion, Tiger, Cat, Dog, Elephant]
// remove() -> pop(): Remove an item from the end of an array
animals.remove(animals.size() - 1);
System.out.println(animals); // [Lion, Tiger, Cat, Dog]
// add(0,"xyz") -> unshift(): Add items to the beginning of an array
animals.add(0, "Penguin");
System.out.println(animals); // [Penguin, Lion, Tiger, Cat, Dog]
// remove(0) -> shift(): Remove an item from the beginning of an array
animals.remove(0);
System.out.println(animals); // [Lion, Tiger, Cat, Dog]
}
}
Send a SMS via intent
- Manifest permission (you can put it after or before "application" )
uses-permission android:name="android.permission.SEND_SMS"/>
- make a button for example and write the below code ( as written before by
Prem
at this thread ) and replace the below phone_Number by an actual number, it will work:
startActivity(new Intent(Intent.ACTION_VIEW, Uri.fromParts("sms", "phone_Number", null)));
Redirect HTTP to HTTPS on default virtual host without ServerName
This is the complete way to omit unneeded redirects, too ;)
These rules are intended to be used in .htaccess files, as a RewriteRule in a *:80 VirtualHost entry needs no Conditions.
RewriteEngine on
RewriteCond %{HTTPS} off [OR]
RewriteCond %{HTTP:X-Forwarded-Proto} !https
RewriteRule ^/(.*) https://%{HTTP_HOST}/$1 [NC,R=301,L]
Eplanations:
RewriteEngine on
==> enable the engine at all
RewriteCond %{HTTPS} off [OR]
==> match on non-https connections, or (not setting [OR] would cause an implicit AND !)
RewriteCond %{HTTP:X-Forwarded-Proto} !https
==> match on forwarded connections (proxy, loadbalancer, etc.) without https
RewriteRule ^/(.*) https://%{HTTP_HOST}/$1 [NC,R=301,L]
==> if one of both Conditions match, do the rewrite of the whole URL, sending a 301 to have this 'learned' by the client (some do, some don't) and the L for the last rule.
Are there any standard exit status codes in Linux?
Programs return a 16 bit exit code. If the program was killed with a signal then the high order byte contains the signal used, otherwise the low order byte is the exit status returned by the programmer.
How that exit code is assigned to the status variable $? is then up to the shell. Bash keeps the lower 7 bits of the status and then uses 128 + (signal nr) for indicating a signal.
The only "standard" convention for programs is 0 for success, non-zero for error. Another convention used is to return errno on error.
How to run an android app in background?
As apps run in the background anyway. I’m assuming what your really asking is how do you make apps do stuff in the background. The solution below will make your app do stuff in the background after opening the app and after the system has rebooted.
Below, I’ve added a link to a fully working example (in the form of an Android Studio Project)
This subject seems to be out of the scope of the Android docs, and there doesn’t seem to be any one comprehensive doc on this. The information is spread across a few docs.
The following docs tell you indirectly how to do this:
https://developer.android.com/reference/android/app/Service.html
https://developer.android.com/reference/android/content/BroadcastReceiver.html
https://developer.android.com/guide/components/bound-services.html
In the interests of getting your usage requirements correct, the important part of this above doc to read carefully is: #Binder, #Messenger and the components link below:
https://developer.android.com/guide/components/aidl.html
Here is the link to a fully working example (in Android Studio format): http://developersfound.com/BackgroundServiceDemo.zip
This project will start an Activity which binds to a service; implementing the AIDL.
This project is also useful to re-factor for the purpose of IPC across different apps.
This project is also developed to start automatically when Android restarts (provided the app has been run at least one after installation and app is not installed on SD card)
When this app/project runs after reboot, it dynamically uses a transparent view to make it look like no app has started but the service of the associated app starts cleanly.
This code is written in such a way that it’s very easy to tweak to simulate a scheduled service.
This project is developed in accordance to the above docs and is subsequently a clean solution.
There is however a part of this project which is not clean being: I have not found a way to start a service on reboot without using an Activity. If any of you guys reading this post have a clean way to do this please post a comment.
Cmake doesn't find Boost
I had the same problem while trying to run make
for a project after installing Boost version 1.66.0 on Ubuntu Trusty64. The error message was similar to (not exactly like) this one:
CMake Error at
/usr/local/Cellar/cmake/3.3.2/share/cmake/Modules/FindBoost.cmake:1245 (message):
Unable to find the requested Boost libraries.
Boost version: 0.0.0
Boost include path: /usr/include
Detected version of Boost is too old. Requested version was 1.36 (or newer).
Call Stack (most recent call first):
CMakeLists.txt:10 (FIND_PACKAGE)
Boost was definitely installed, but CMake couldn't detect it. After spending plenty of time tinkering with paths and environmental variables, I eventually ended up checking cmake
itself for options and found the following:
--check-system-vars = Find problems with variable usage in system files
So I ran the following in the directory at issue:
sudo cmake --check-system-vars
which returned:
Also check system files when warning about unused and uninitialized variables.
-- Boost version: 1.66.0
-- Found the following Boost libraries:
-- system
-- filesystem
-- thread
-- date_time
-- chrono
-- regex
-- serialization
-- program_options
-- Found Git: /usr/bin/git
-- Configuring done
-- Generating done
-- Build files have been written to: /home/user/myproject
and resolved the issue.
How to get the sizes of the tables of a MySQL database?
SELECT
table_name AS "Table",
round(((data_length + index_length) / 1024 / 1024), 2) as size
FROM information_schema.TABLES
WHERE table_schema = "YOUR_DATABASE_NAME"
ORDER BY size DESC;
This sorts the sizes (DB Size in MB).
foreach with index
You can do the following
foreach (var it in someCollection.Select((x, i) => new { Value = x, Index = i }) )
{
if (it.Index > SomeNumber) //
}
This will create an anonymous type value for every entry in the collection. It will have two properties
Value
: with the original value in the collection
Index
: with the index within the collection
What is the difference between bool and Boolean types in C#
Perhaps bool is a tad "lighter" than Boolean; Interestingly, changing this:
namespace DuckbillServerWebAPI.Models
{
public class Expense
{
. . .
public bool CanUseOnItems { get; set; }
}
}
...to this:
namespace DuckbillServerWebAPI.Models
{
public class Expense
{
. . .
public Boolean CanUseOnItems { get; set; }
}
}
...caused my cs file to sprout a "using System;" Changing the type back to "bool" caused the using clause's hair to turn grey.
(Visual Studio 2010, WebAPI project)
Change background of LinearLayout in Android
android:background="@drawable/ic_launcher"
should be included inside Layout tab.
where ic_launcher is image name that u can put inside project folder/res/drawable .
you can copy any number of images and make it as background
CSS animation delay in repeating
Another way you can achieve a pause between animations is to apply a second animation that hides the element for the amount of delay you want. This has the benefit of allowing you to use a CSS easing function like you would normally.
.star {
animation: shooting-star 1000ms ease-in-out infinite,
delay-animation 2000ms linear infinite;
}
@keyframes shooting-star {
0% {
transform: translate(0, 0) rotate(45deg);
}
100% {
transform: translate(300px, 300px) rotate(45deg);
}
}
@keyframes delay-animation {
0% {
opacity: 1;
}
50% {
opacity: 1;
}
50.01% {
opacity: 0;
}
100% {
opacity: 0;
}
}
This only works if you want the delay to be a multiple of the animation duration. I used this to make a shower of shooting stars appear more random:
https://codepen.io/ericdjohnson/pen/GRpOgVO
Time stamp in the C programming language
Use @Arkaitz Jimenez's code to get two timevals:
#include <sys/time.h>
//...
struct timeval tv1, tv2, diff;
// get the first time:
gettimeofday(&tv1, NULL);
// do whatever it is you want to time
// ...
// get the second time:
gettimeofday(&tv2, NULL);
// get the difference:
int result = timeval_subtract(&diff, &tv1, &tv2);
// the difference is storid in diff now.
Sample code for timeval_subtract can be found at this web site:
/* Subtract the `struct timeval' values X and Y,
storing the result in RESULT.
Return 1 if the difference is negative, otherwise 0. */
int
timeval_subtract (result, x, y)
struct timeval *result, *x, *y;
{
/* Perform the carry for the later subtraction by updating y. */
if (x->tv_usec < y->tv_usec) {
int nsec = (y->tv_usec - x->tv_usec) / 1000000 + 1;
y->tv_usec -= 1000000 * nsec;
y->tv_sec += nsec;
}
if (x->tv_usec - y->tv_usec > 1000000) {
int nsec = (x->tv_usec - y->tv_usec) / 1000000;
y->tv_usec += 1000000 * nsec;
y->tv_sec -= nsec;
}
/* Compute the time remaining to wait.
tv_usec is certainly positive. */
result->tv_sec = x->tv_sec - y->tv_sec;
result->tv_usec = x->tv_usec - y->tv_usec;
/* Return 1 if result is negative. */
return x->tv_sec < y->tv_sec;
}
In STL maps, is it better to use map::insert than []?
A gotcha with map::insert() is that it won't replace a value if the key already exists in the map. I've seen C++ code written by Java programmers where they have expected insert() to behave the same way as Map.put() in Java where values are replaced.
String.strip() in Python
In this case, you might get some differences. Consider a line like:
"foo\tbar "
In this case, if you strip
, then you'll get {"foo":"bar"}
as the dictionary entry. If you don't strip, you'll get {"foo":"bar "}
(note the extra space at the end)
Note that if you use line.split()
instead of line.split('\t')
, you'll split on every whitespace character and the "strip
ing" will be done during splitting automatically. In other words:
line.strip().split()
is always identical to:
line.split()
but:
line.strip().split(delimiter)
Is not necessarily equivalent to:
line.split(delimiter)
working with negative numbers in python
Try this on your TA:
# Simulate multiplying two N-bit two's-complement numbers
# into a 2N-bit accumulator
# Use shift-add so that it's O(base_2_log(N)) not O(N)
for numa, numb in ((3, 5), (-3, 5), (3, -5), (-3, -5), (-127, -127)):
print numa, numb,
accum = 0
negate = False
if numa < 0:
negate = True
numa = -numa
while numa:
if numa & 1:
accum += numb
numa >>= 1
numb <<= 1
if negate:
accum = -accum
print accum
output:
3 5 15
-3 5 -15
3 -5 -15
-3 -5 15
-127 -127 16129
enumerate() for dictionary in python
Python3:
One solution:
enumm = {0: 1, 1: 2, 2: 3, 4: 4, 5: 5, 6: 6, 7: 7}
for i, k in enumerate(enumm):
print("{}) d.key={}, d.value={}".format(i, k, enumm[k]))
Output:
0) enumm.key=0, enumm.value=1
1) enumm.key=1, enumm.value=2
2) enumm.key=2, enumm.value=3
3) enumm.key=4, enumm.value=4
4) enumm.key=5, enumm.value=5
5) enumm.key=6, enumm.value=6
6) enumm.key=7, enumm.value=7
An another example:
d = {1 : {'a': 1, 'b' : 2, 'c' : 3},
2 : {'a': 10, 'b' : 20, 'c' : 30}
}
for i, k in enumerate(d):
print("{}) key={}, value={}".format(i, k, d[k])
Output:
0) key=1, value={'a': 1, 'b': 2, 'c': 3}
1) key=2, value={'a': 10, 'b': 20, 'c': 30}
What is duck typing?
Wikipedia has a fairly detailed explanation:
http://en.wikipedia.org/wiki/Duck_typing
duck typing is a style of dynamic
typing in which an object's current
set of methods and properties
determines the valid semantics, rather
than its inheritance from a particular
class or implementation of a specific
interface.
The important note is likely that with duck typing a developer is concerned more with the parts of the object that are consumed rather than what the actual underlying type is.
How to update one file in a zip archive
From zip(1):
When given the name of an existing zip archive, zip will replace identically named entries in the zip archive or add entries for new names.
So just use the zip
command as you normally would to create a new .zip file containing only that one file, except the .zip filename you specify will be the existing archive.
Error message: "'chromedriver' executable needs to be available in the path"
If you are working with robot framework RIDE. Then you can download Chromedriver.exe
from its official website and keep this .exe file in C:\Python27\Scripts
directory. Now mention this path as your environment variable eg. C:\Python27\Scripts\chromedriver.exe
.
Restart your computer and run same test case again. You will not get this problem again.
Long vs Integer, long vs int, what to use and when?
When it comes to using a very long number that may exceed 32 bits to represent, you may use long to make sure that you'll not have strange behavior.
From Java 5 you can use in-boxing and out-boxing features to make the use of int and Integer completely the same. It means that you can do :
int myInt = new Integer(11);
Integer myInt2 = myInt;
The in and out boxing allow you to switch between int and Integer without any additional conversion (same for Long
,Double
,Short
too)
You may use int
all the time, but Integer
contains some helper methods that can help you to do some complex operations with integers (such as Integer.parseInt(String)
)
CSS image overlay with color and transparency
JSFiddle Demo
HTML:
<div class="image-holder">
<img src="http://codemancers.com/img/who-we-are-bg.png" />
</div>
CSS:
.image-holder {
display:inline-block;
position: relative;
}
.image-holder:after {
content:'';
top: 0;
left: 0;
z-index: 10;
width: 100%;
height: 100%;
display: block;
position: absolute;
background: blue;
opacity: 0.1;
}
.image-holder:hover:after {
opacity: 0;
}
What is `related_name` used for in Django?
The related name parameter is actually an option. If we do not set it, Django
automatically creates the other side of the relation for us. In the case of the Map model,
Django would have created a map_set
attribute, allowing access via m.map_set
in your
example(m being your class instance). The formula Django uses is the name of the model followed by the
string _set
. The related name parameter thus simply overrides Django’s default rather
than providing new behavior.
Regex for string not ending with given suffix
The accepted answer is fine if you can use lookarounds. However, there is also another approach to solve this problem.
If we look at the widely proposed regex for this question:
.*[^a]$
We will find that it almost works. It does not accept an empty string, which might be a little inconvinient. However, this is a minor issue when dealing with just a one character. However, if we want to exclude whole string, e.g. "abc", then:
.*[^a][^b][^c]$
won't do. It won't accept ac, for example.
There is an easy solution for this problem though. We can simply say:
.{,2}$|.*[^a][^b][^c]$
or more generalized version:
.{,n-1}$|.*[^firstchar][^secondchar]$
where n is length of the string you want forbid (for abc
it's 3), and firstchar
, secondchar
, ... are first, second ... nth characters of your string (for abc
it would be a
, then b
, then c
).
This comes from a simple observation that a string that is shorter than the text we won't forbid can not contain this text by definition. So we can either accept anything that is shorter("ab" isn't "abc"), or anything long enough for us to accept but without the ending.
Here's an example of find that will delete all files that are not .jpg:
find . -regex '.{,3}$|.*[^.][^j][^p][^g]$' -delete
how to use JSON.stringify and json_decode() properly
When you save some data using JSON.stringify() and then need to read that in php. The following code worked for me.
json_decode( html_entity_decode( stripslashes ($jsonString ) ) );
Thanks to @Thisguyhastwothumbs
Check if object is a jQuery object
You can check if the object is produced by JQuery with the jquery
property:
myObject.jquery // 3.3.1
=> return the number of the JQuery version if the object produced by JQuery.
=> otherwise, it returns undefined
MVC : The parameters dictionary contains a null entry for parameter 'k' of non-nullable type 'System.Int32'
It appears that you are using the default route which is defined as this:
routes.MapRoute(
name: "Default",
url: "{controller}/{action}/{id}",
defaults: new { controller = "Home", action = "Index", id = UrlParameter.Optional }
);
The key part of that route is the {id}
piece. If you look at your action method, your parameter is k
instead of id
. You need to change your action method to this so that it matches the route parameter:
// change int k to int id
public ActionResult DetailsData(int id)
If you wanted to leave your parameter as k, then you would change the URL to be:
http://localhost:7317/Employee/DetailsData?k=4
You also appear to have a problem with your connection string. In your web.config, you need to change your connection string to this (provided by haim770 in another answer that he deleted):
<connectionStrings>
<add name="EmployeeContext"
connectionString="Server=.;Database=mytry;integrated security=True;"
providerName="System.Data.SqlClient" />
</connectionStrings>
Fetching data from MySQL database to html dropdown list
To do this you want to loop through each row of your query results and use this info for each of your drop down's options. You should be able to adjust the code below fairly easily to meet your needs.
// Assume $db is a PDO object
$query = $db->query("YOUR QUERY HERE"); // Run your query
echo '<select name="DROP DOWN NAME">'; // Open your drop down box
// Loop through the query results, outputing the options one by one
while ($row = $query->fetch(PDO::FETCH_ASSOC)) {
echo '<option value="'.$row['something'].'">'.$row['something'].'</option>';
}
echo '</select>';// Close your drop down box
Global Git ignore
I am able to ignore a .tmproj
file by including either .tmproj
or *.tmproj
in my /users/me/.gitignore-global
file.
Note that the file name is .gitignore-global
not .gitignore
. It did not work by including .tmproj
or *.tmproj
in a file called .gitignore
in the /users/me
directory.
How to merge remote changes at GitHub?
This problem can also occur when you have conflicting tags. If your local version and remote version use same tag name for different commits, you can end up here.
You can solve it my deleting the local tag:
$ git tag --delete foo_tag
What exactly is a Maven Snapshot and why do we need it?
The three others answers provide you a good vision of what a -SNAPSHOT
version is. I just wanted to add some information regarding the behavior of Maven when it finds a SNAPSHOT
dependency.
When you build an application, Maven will search for dependencies in the local repository. If a stable version is not found there, it will search the remote repositories (defined in settings.xml
or pom.xml
) to retrieve this dependency. Then, it will copy it into the local repository, to make it available for the next builds.
For example, a foo-1.0.jar
library is considered as a stable version, and if Maven finds it in the local repository, it will use this one for the current build.
Now, if you need a foo-1.0-SNAPSHOT.jar
library, Maven will know that this version is not stable and is subject to changes. That's why Maven will try to find a newer version in the remote repositories, even if a version of this library is found on the local repository. However, this check is made only once per day. That means that if you have a foo-1.0-20110506.110000-1.jar
(i.e. this library has been generated on 2011/05/06 at 11:00:00) in your local repository, and if you run the Maven build again the same day, Maven will not check the repositories for a newer version.
Maven provides you a way to change this update policy in your repository definition:
<repository>
<id>foo-repository</id>
<url>...</url>
<snapshots>
<enabled>true</enabled>
<updatePolicy>XXX</updatePolicy>
</snapshots>
</repository>
where XXX
can be:
- always: Maven will check for a newer version on every build;
- daily, the default value;
- interval:XXX: an interval in minutes (XXX)
- never: Maven will never try to retrieve another version. It will do that only if it doesn't exist locally. With the configuration,
SNAPSHOT
version will be handled as the stable libraries.
(model of the settings.xml can be found here)
Setting up MySQL and importing dump within Dockerfile
Each RUN
instruction in a Dockerfile
is executed in a different layer (as explained in the documentation of RUN
).
In your Dockerfile
, you have three RUN
instructions. The problem is that MySQL server is only started in the first. In the others, no MySQL are running, that is why you get your connection error with mysql
client.
To solve this problem you have 2 solutions.
Solution 1: use a one-line RUN
RUN /bin/bash -c "/usr/bin/mysqld_safe --skip-grant-tables &" && \
sleep 5 && \
mysql -u root -e "CREATE DATABASE mydb" && \
mysql -u root mydb < /tmp/dump.sql
Solution 2: use a script
Create an executable script init_db.sh
:
#!/bin/bash
/usr/bin/mysqld_safe --skip-grant-tables &
sleep 5
mysql -u root -e "CREATE DATABASE mydb"
mysql -u root mydb < /tmp/dump.sql
Add these lines to your Dockerfile
:
ADD init_db.sh /tmp/init_db.sh
RUN /tmp/init_db.sh
TOMCAT - HTTP Status 404
You don't have to use Tomcat installation as a server location. It is much easier just to copy the files in the ROOT folder.
Eclipse forgets to copy the default apps (ROOT, examples, etc.) when
it creates a Tomcat folder inside the Eclipse workspace. Go to
C:\apache-tomcat-7.0.8\webapps
, R-click on the ROOT folder and copy
it. Then go to your Eclipse workspace, go to the .metadata
folder, and
search for "wtpwebapps". You should find something like
your-eclipse-workspace\.metadata\.plugins\org.eclipse.wst.server.core\tmp0\wtpwebapps
(or ../tmp1/wtpwebapps
if you already had another server registered
in Eclipse). Go to the wtpwebapps
folder, R-click, and paste ROOT (say
"yes" if asked if you want to merge/replace folders/files). Then
reload http://localhost/
to see the Tomcat welcome page.
Source: HTTP Status 404 error in tomcat
How to convert an XML file to nice pandas dataframe?
Here is another way of converting a xml to pandas data frame. For example i have parsing xml from a string but this logic holds good from reading file as well.
import pandas as pd
import xml.etree.ElementTree as ET
xml_str = '<?xml version="1.0" encoding="utf-8"?>\n<response>\n <head>\n <code>\n 200\n </code>\n </head>\n <body>\n <data id="0" name="All Categories" t="2018052600" tg="1" type="category"/>\n <data id="13" name="RealEstate.com.au [H]" t="2018052600" tg="1" type="publication"/>\n </body>\n</response>'
etree = ET.fromstring(xml_str)
dfcols = ['id', 'name']
df = pd.DataFrame(columns=dfcols)
for i in etree.iter(tag='data'):
df = df.append(
pd.Series([i.get('id'), i.get('name')], index=dfcols),
ignore_index=True)
df.head()
Selenium using Java - The path to the driver executable must be set by the webdriver.gecko.driver system property
Every Driver service in selenium calls the similar code(following is the firefox specific code) while creating the driver object
@Override
protected File findDefaultExecutable() {
return findExecutable(
"geckodriver", GECKO_DRIVER_EXE_PROPERTY,
"https://github.com/mozilla/geckodriver",
"https://github.com/mozilla/geckodriver/releases");
}
now for the driver that you want to use, you have to set the system property with the value of path to the driver executable.
for firefox GECKO_DRIVER_EXE_PROPERTY = "webdriver.gecko.driver" and this can be set before creating the driver object as below
System.setProperty("webdriver.gecko.driver", "./libs/geckodriver.exe");
WebDriver driver = new FirefoxDriver();
Error: Microsoft Visual C++ 10.0 is required (Unable to find vcvarsall.bat) when running Python script
Tried to install lxml, grab and other extensions, which requires VS 10.0+ and get the same issue. I find own way to solve this problem(Windows 10 x64, Python 3.4+):
Install Visual C++ 2010 Express (download). (Do not install Microsoft Visual Studio 2010 Service Pack 1 )
Remove all the Microsoft Visual C++ 2010 Redistributable packages from Control Panel\Programs and Features. If you don't do those then the install is going to fail with an obscure "Fatal error during installation" error.
Install offline version of Windows SDK for Visual Studio 2010 (v7.1) (download). This is required for 64bit extensions. Windows has builtin mounting for ISOs. Just mount the ISO and run Setup\SDKSetup.exe instead of setup.exe.
Create a vcvars64.bat file in C:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\bin\amd64 that contains:
CALL "C:\Program Files\Microsoft SDKs\Windows\v7.1\Bin\SetEnv.cmd" /x64
Find extension on this site, then put them into the python folder, and install .whl extension with pip:
python -m pip install extensionname.whl
Enjoy
Converting int to string in C
Use snprintf
- it is standard an available in every compilator. Query it for the size needed by calling it with NULL, 0
parameters. Allocate one character more for null at the end.
int length = snprintf( NULL, 0, "%d", x );
char* str = malloc( length + 1 );
snprintf( str, length + 1, "%d", x );
...
free(str);
Return a 2d array from a function
The function returns a static 2D array
const int N = 6;
int (*(MakeGridOfCounts)())[N] {
static int cGrid[N][N] = {{0, }, {0, }, {0, }, {0, }, {0, }, {0, }};
return cGrid;
}
int main() {
int (*arr)[N];
arr = MakeGridOfCounts();
}
You need to make the array static since it will be having a block scope, when the function call ends, the array will be created and destroyed. Static scope variables last till the end of program.
Extracting just Month and Year separately from Pandas Datetime column
You can directly access the year
and month
attributes, or request a datetime.datetime
:
In [15]: t = pandas.tslib.Timestamp.now()
In [16]: t
Out[16]: Timestamp('2014-08-05 14:49:39.643701', tz=None)
In [17]: t.to_pydatetime() #datetime method is deprecated
Out[17]: datetime.datetime(2014, 8, 5, 14, 49, 39, 643701)
In [18]: t.day
Out[18]: 5
In [19]: t.month
Out[19]: 8
In [20]: t.year
Out[20]: 2014
One way to combine year and month is to make an integer encoding them, such as: 201408
for August, 2014. Along a whole column, you could do this as:
df['YearMonth'] = df['ArrivalDate'].map(lambda x: 100*x.year + x.month)
or many variants thereof.
I'm not a big fan of doing this, though, since it makes date alignment and arithmetic painful later and especially painful for others who come upon your code or data without this same convention. A better way is to choose a day-of-month convention, such as final non-US-holiday weekday, or first day, etc., and leave the data in a date/time format with the chosen date convention.
The calendar
module is useful for obtaining the number value of certain days such as the final weekday. Then you could do something like:
import calendar
import datetime
df['AdjustedDateToEndOfMonth'] = df['ArrivalDate'].map(
lambda x: datetime.datetime(
x.year,
x.month,
max(calendar.monthcalendar(x.year, x.month)[-1][:5])
)
)
If you happen to be looking for a way to solve the simpler problem of just formatting the datetime column into some stringified representation, for that you can just make use of the strftime
function from the datetime.datetime
class, like this:
In [5]: df
Out[5]:
date_time
0 2014-10-17 22:00:03
In [6]: df.date_time
Out[6]:
0 2014-10-17 22:00:03
Name: date_time, dtype: datetime64[ns]
In [7]: df.date_time.map(lambda x: x.strftime('%Y-%m-%d'))
Out[7]:
0 2014-10-17
Name: date_time, dtype: object
How do I flush the PRINT buffer in TSQL?
Another better option is to not depend on PRINT or RAISERROR and just load your "print" statements into a ##Temp table in TempDB or a permanent table in your database which will give you visibility to the data immediately via a SELECT statement from another window. This works the best for me. Using a permanent table then also serves as a log to what happened in the past. The print statements are handy for errors, but using the log table you can also determine the exact point of failure based on the last logged value for that particular execution (assuming you track the overall execution start time in your log table.)
Adding files to java classpath at runtime
You can only add folders or jar files to a class loader. So if you have a single class file, you need to put it into the appropriate folder structure first.
Here is a rather ugly hack that adds to the SystemClassLoader at runtime:
import java.io.IOException;
import java.io.File;
import java.net.URLClassLoader;
import java.net.URL;
import java.lang.reflect.Method;
public class ClassPathHacker {
private static final Class[] parameters = new Class[]{URL.class};
public static void addFile(String s) throws IOException {
File f = new File(s);
addFile(f);
}//end method
public static void addFile(File f) throws IOException {
addURL(f.toURL());
}//end method
public static void addURL(URL u) throws IOException {
URLClassLoader sysloader = (URLClassLoader) ClassLoader.getSystemClassLoader();
Class sysclass = URLClassLoader.class;
try {
Method method = sysclass.getDeclaredMethod("addURL", parameters);
method.setAccessible(true);
method.invoke(sysloader, new Object[]{u});
} catch (Throwable t) {
t.printStackTrace();
throw new IOException("Error, could not add URL to system classloader");
}//end try catch
}//end method
}//end class
The reflection is necessary to access the protected method addURL
. This could fail if there is a SecurityManager.
What does ==$0 (double equals dollar zero) mean in Chrome Developer Tools?
I will say It 's just shorthand syntax for get reference of html element during debugging time , normaly these kind of task will perform by these method
document.getElementById , document.getElementsByClassName , document.querySelector
so clicking on an html element and getting a reference variable ($0) in console is a huge time saving during the day
What does __FILE__ mean in Ruby?
It is a reference to the current file name. In the file foo.rb
, __FILE__
would be interpreted as "foo.rb"
.
Edit: Ruby 1.9.2 and 1.9.3 appear to behave a little differently from what Luke Bayes said in his comment. With these files:
# test.rb
puts __FILE__
require './dir2/test.rb'
# dir2/test.rb
puts __FILE__
Running ruby test.rb
will output
test.rb
/full/path/to/dir2/test.rb
Bootstrap 3 select input form inline
This is how I made it without extra css or jquery:
<div class="form-group">
<div class="input-group">
<label class="sr-only" for="extra3">Extra name 3</label>
<input type="text" id="extra3" class="form-control" placeholder="Extra name">
<span class="input-group-addon">
<label class="checkbox-inline">
Mandatory? <input type="checkbox" id="inlineCheckbox5" value="option1">
</label>
</span>
<span class="input-group-addon">
<label class="checkbox-inline">
Per person? <input type="checkbox" id="inlineCheckbox6" value="option2">
</label>
</span>
<span class="input-group-addon">
To be paid?
<select>
<option value="online">Online</option>
<option value="on spot">On Spot</option>
</select>
</span>
</div>
</div>
Properly escape a double quote in CSV
I know this is an old post, but here's how I solved it (along with converting null values to empty string) in C# using an extension method.
Create a static class with something like the following:
/// <summary>
/// Wraps value in quotes if necessary and converts nulls to empty string
/// </summary>
/// <param name="value"></param>
/// <returns>String ready for use in CSV output</returns>
public static string Q(this string value)
{
if (value == null)
{
return string.Empty;
}
if (value.Contains(",") || (value.Contains("\"") || value.Contains("'") || value.Contains("\\"))
{
return "\"" + value + "\"";
}
return value;
}
Then for each string you're writing to CSV, instead of:
stringBuilder.Append( WhateverVariable );
You just do:
stringBuilder.Append( WhateverVariable.Q() );
react hooks useEffect() cleanup for only componentWillUnmount?
To add to the accepted answer, I had a similar issue and solved it using a similar approach with the contrived example below. In this case I needed to log some parameters on componentWillUnmount
and as described in the original question I didn't want it to log every time the params changed.
const componentWillUnmount = useRef(false)
// This is componentWillUnmount
useEffect(() => {
return () => {
componentWillUnmount.current = true
}
}, [])
useEffect(() => {
return () => {
// This line only evaluates to true after the componentWillUnmount happens
if (componentWillUnmount.current) {
console.log(params)
}
}
}, [params]) // This dependency guarantees that when the componentWillUnmount fires it will log the latest params