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Extract substring in Bash
Given a filename in the form someletters_12345_moreleters.ext , I want to extract the 5 digits and put them into a variable.
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Is there a performance difference between a for loop and a for-each loop?
...g4j.Marker, org.apache.logging.log4j.Marker...);
Code:
0: iconst_0
1: istore_2
2: aload_1
3: arraylength
4: istore_3
5: iload_2
6: iload_3
7: if_icmpge 29
10: aload_1
11: iload_2
12: aaload
13: astore 4
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Is there a REAL performance difference between INT and VARCHAR primary keys?
...(think US States, Country Codes) and a coworker won't budge on the INT AUTO_INCREMENT as a primary key for all tables.
14 ...
Does MongoDB's $in clause guarantee order
...ly have two options.
So let's say that you were matching on the values of _id in your documents with an array that is going to be passed in to the $in as [ 4, 2, 8 ].
Approach using Aggregate
var list = [ 4, 2, 8 ];
db.collection.aggregate([
// Match the selected documents by "_id"
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How to pretty print nested dictionaries?
...ues in Py2, it's cause it can't handle Unicode properly without hacks like __future__ that the answer now mentions, so you have to employ those wherever needed (or update to 3 already).
– sudo
Feb 14 '18 at 18:10
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Meaning of @classmethod and @staticmethod for beginner? [duplicate]
...thod can have no parameters at all.
Example
class Date(object):
def __init__(self, day=0, month=0, year=0):
self.day = day
self.month = month
self.year = year
@classmethod
def from_string(cls, date_as_string):
day, month, year = map(int, date_as_string...
Flask-SQLAlchemy import/context issue
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The flask_sqlalchemy module does not have to be initialized with the app right away - you can do this instead:
# apps.members.models
from flask_sqlalchemy import SQLAlchemy
db = SQLAlchemy()
class Member(db.Model):
# fields her...
Sharing a result queue among several processes
... can I share a queue with asynchronous worker processes started with apply_async ? I don't need dynamic joining or anything else, just a way for the workers to (repeatedly) report their results back to base.
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Replace all non Alpha Numeric characters, New Lines, and multiple White Space with one Space
... \W leaves the underscore. A short equivalent for [^a-zA-Z0-9] would be [\W_]
text.replace(/[\W_]+/g," ");
\W is the negation of shorthand \w for [A-Za-z0-9_] word characters (including the underscore)
Example at regex101.com
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How to convert vector to array
...?
If you're calling an API function that expects the former, you can do do_something(&v[0], v.size()), where v is a vector of doubles. The elements of a vector are contiguous.
Otherwise, you just have to copy each element:
double arr[100];
std::copy(v.begin(), v.end(), arr);
Ensure not only...