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How to “EXPIRE” the “HSET” child key in redis?
... mentioning:
When having a hash, the structure basically looks like:
hash_top_key
- child_key_1 -> some_value
- child_key_2 -> some_value
...
- child_key_n -> some_value
Since we want to add TTL to the child keys, we can move them to top keys. The main point is that the key now ...
Algorithm to detect corners of paper sheet in photo
...(in OpenCV use findcontour() with some simple parameters, I think I used CV_RETR_LIST). might still struggle when it's on a white piece of paper, but was definitely providing best results.
For the Houghline2() Transform, try with the CV_HOUGH_STANDARD as opposed to the CV_HOUGH_PROBABILISTIC, it'l...
What are the details of “Objective-C Literals” mentioned in the Xcode 4.4 release notes?
...
This part is new. Expression Literals
When you have an expression (M_PI / 16 for example) you should put it inside parenthesis.
This syntax works for numeral expressions, booleans, finding an index in a (C-) string, boolean values, enum constants, and even character strings!
NSNumber *piO...
How to sort an IEnumerable
...myList = myEnumerable.ToList();
myList.Sort();
Based on your comment:
_components = (from c in xml.Descendants("component")
let value = (string)c
orderby value
select value
)
.Distinct()
.ToList();
or
_com...
How to dynamically compose an OR query filter in Django?
...'s say with a list
# of db fields that can change like the following
# list_with_strings = ['dbfield1', 'dbfield2', 'dbfield3']
# init our q objects variable to use .add() on it
q_objects = Q(id__in=[])
# loop trough the list and create an OR condition for each item
for item in list:
q_objects...
Update MongoDB field using value of another field
...; {
requests.push( {
'updateOne': {
'filter': { '_id': document._id },
'update': { '$set': { 'name': document.name } }
}
});
if (requests.length === 500) {
//Execute per 500 operations and re-init
db.collection.bulkWrite(requests)...
Basic http file downloading and saving to disk in python?
...URLopener is deprecated.
And when used you will get error as below:
url_opener = urllib.URLopener() AttributeError: module 'urllib' has no
attribute 'URLopener'
So, try:
import urllib.request
urllib.request.urlretrieve(url, filename)
...
Print current call stack from a method in Python code
...port traceback
def f():
g()
def g():
for line in traceback.format_stack():
print(line.strip())
f()
# Prints:
# File "so-stack.py", line 10, in <module>
# f()
# File "so-stack.py", line 4, in f
# g()
# File "so-stack.py", line 7, in g
# for line in traceback.form...
How do I raise the same Exception with a custom message in Python?
...Note that you can add whatever you like to err. For example err.problematic_array=[1,2,3].
Edit: @Ducan points in a comment the above does not work with python 3 since .message is not a member of ValueError. Instead you could use this (valid python 2.6 or later or 3.x):
try:
try:
raise...
Shell script while read line loop stops after the first line
...
The problem is that do_work.sh runs ssh commands and by default ssh reads from stdin which is your input file. As a result, you only see the first line processed, because ssh consumes the rest of the file and your while loop terminates.
To preve...