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How to empty a list?
...
This actually removes the contents from the list, but doesn't replace the old label with a new empty list:
del lst[:]
Here's an example:
lst1 = [1, 2, 3]
lst2 = lst1
del lst1[:]
print(lst2)
For the sake of completeness, the slic...
jekyll markdown internal links
...ou can now post internal links by using the following:
[Some Link]({% post_url 2010-07-21-name-of-post %})
This is also referenced in the Jekyll Documentation.
https://github.com/mojombo/jekyll/pull/369
share
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...
How to use GROUP_CONCAT in a CONCAT in MySQL
...what you need.
Update
Splitting in two steps. First we get a table having all values(comma separated) against a unique[Name,id]. Then from obtained table we get all names and values as a single value against each unique id
See this explained here SQL Fiddle Demo (scroll down as it has two result se...
Sending files using POST with HttpURLConnection
...one can provide me with a good example on how to send a bitmap "file" (actually an in-memory stream) via POST to an Apache HTTP server. I'm not interested in cookies or authentication or anything complicated, but I just want to have a reliable and logic implementation. All the examples that I've see...
PHP: How to generate a random, unique, alphanumeric string for use in a secret link?
...of an application. In particular, rand() and uniqid() are not cryptographically secure random number generators. See Scott's answer for a secure alternative.
If you do not need it to be absolutely unique over time:
md5(uniqid(rand(), true))
Otherwise (given you have already determined a unique l...
How to check Oracle database for long running queries
...ime -- Time since current mode was granted
from
v$locked_object, all_objects, v$lock
where
v$locked_object.object_id = all_objects.object_id AND
v$lock.id1 = all_objects.object_id AND
v$lock.sid = v$locked_object.session_id
order by
session_id, ctime desc, object_name
/
This is a...
What's the difference between ES6 Map and WeakMap?
...e: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/WeakMap):
Keys of WeakMaps are of the type Object only. Primitive data types as
keys are not allowed (e.g. a Symbol can't be a WeakMap key).
Nor can a string, number, or boolean be used as a WeakMap key. A M...
Why does volatile exist?
...ed 16 bit value as a semaphore to know when the other guy was done. Essentially we did this:
void waitForSemaphore()
{
volatile uint16_t* semPtr = WELL_KNOWN_SEM_ADDR;/*well known address to my semaphore*/
while ((*semPtr) != IS_OK_FOR_ME_TO_PROCEED);
}
Without volatile, the optimizer sees ...
Should I use alias or alias_method?
I found a blog post on alias vs. alias_method . As shown in the example given in that blog post, I simply want to alias a method to another within the same class. Which should I use? I always see alias used, but someone told me alias_method is better.
...
How can I find and run the keytool
...n by myself as below quote. It works fine.
"C:\Program Files\Java\jdk1.6.0_26\bin\keytool.exe" -exportcert -alias
> sociallisting -keystore "D:\keystore\SocialListing" |
> "C:\cygwin\bin\openssl.exe" sha1 -binary | "C:\cygwin\bin\openssl.exe"
> base64
...