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sed beginner: changing all occurrences in a folder
...r own code. SO is not a coding service, but a resource for knowledge. High quality, complete answers reinforce this idea, and are more likely to be upvoted. These features, plus the requirement that all posts be self-contained, are some strengths of SO as a platform that differentiates us from forum...
python max function using 'key' and lambda expression
...he object before comparison, or to compare based on a particular attribute/index, you've to use the key argument.
Example 1:
A simple example, suppose you have a list of numbers in string form, but you want to compare those items by their integer value.
>>> lis = ['1', '100', '111', '2'...
how to generate migration to make references polymorphic
...
How do you add index to the references column? Do I need to index that?
– mrudult
Apr 20 '14 at 18:20
...
How to select all records from one table that do not exist in another table?
Query:
12 Answers
12
...
What's the difference between '$(this)' and 'this'?
...e, in .each, the callback function commonly used allows for .each(function(index,element){/*scope*/}). In that scope, this == element is true.
jQuery callbacks use the apply function to bind the function being called with the current element. This element comes from the jQuery object's element arr...
What is the difference between varchar and nvarchar?
...
My two cents
Indexes can fail when not using the correct datatypes:
In SQL Server: When you have an index over a VARCHAR column and present it a Unicode String, SQL Server does not make use of the index. The same thing happens when you ...
configure: error: C compiler cannot create executables
I've checked a number of similar questions on stackoverflow but haven't found an answer yet.
15 Answers
...
Split Python Flask app into multiple files
...tes in the routes directory.
Structure
app.py
routes
__init__.py
index.py
users.py
__init__.py
from flask import Blueprint
routes = Blueprint('routes', __name__)
from .index import *
from .users import *
index.py
from flask import render_template
from . import routes
@routes.ro...
MySQL DISTINCT on a GROUP_CONCAT()
...5),(6),(7),(8),(9),(10);
then we can run this query:
SELECT
SUBSTRING_INDEX(
SUBSTRING_INDEX(tableName.categories, ' ', numbers.n),
' ',
-1) category
FROM
numbers INNER JOIN tableName
ON
LENGTH(tableName.categories)>=
LENGTH(REPLACE(tableName.categories, ' ', ''))+num...
MySQL Creating tables with Foreign Keys giving errno: 150
... of table test/t2:
FOREIGN KEY (t1_id) REFERENCES t1 (id)):
Cannot find an index in the referenced table where the
referenced columns appear as the first columns, or column types
in the table and the referenced table do not match for constraint.
It says that the problem is it can’t find an index...