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What is difference between monolithic and micro kernel?
...e. The kernel can invoke functions directly. Examples of monolithic kernel based OSs: Unix, Linux.
In microkernels, the kernel is broken down into separate processes, known as servers. Some of the servers run in kernel space and some run in user-space. All servers are kept separate and run in diffe...
Difference between rake db:migrate db:reset and db:schema:load
... runs (single) migrations that have not run yet.
db:create creates the database
db:drop deletes the database
db:schema:load creates tables and columns within the (existing) database following schema.rb
db:setup does db:create, db:schema:load, db:seed
db:reset does db:drop, db:setup
db:migrate:reset ...
How to check if a column exists in Pandas
...ments, you can use the get() method for DataFrames. For performing the sum based on the question:
df['sum'] = df.get('A', df['B']) + df['C']
The DataFrame get method has similar behavior as python dictionaries.
share
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Relative URL to a different port number in a hyperlink?
... For instance this modified code just worked for me and moves me from any base port to port 8069 (replace your port as required)
<div>
<a href="http://<?php print
$_SERVER{'SERVER_NAME'}; ?>:8069"><img
src="images/example.png"/>Example Base (http)</a>
<...
Haskell: Converting Int to String
...
An example based on Chuck's answer:
myIntToStr :: Int -> String
myIntToStr x
| x < 3 = show x ++ " is less than three"
| otherwise = "normal"
Note that without the show the third line will not compile.
...
Convert RGBA PNG to RGB with PIL
...e's a version that's much simpler - not sure how performant it is. Heavily based on some django snippet I found while building RGBA -> JPG + BG support for sorl thumbnails.
from PIL import Image
png = Image.open(object.logo.path)
png.load() # required for png.split()
background = Image.new("R...
Get all elements but the first from an array
...ySegment<> implements IList<>, IReadOnlyList<> and their base interfaces (including IEnumerable<>), so you can for example pass an ArraySegment<> to string.Join.
– Jeppe Stig Nielsen
Jan 25 '17 at 8:49
...
Is there a concurrent List in Java's JDK?
...
If you don't care about having index-based access and just want the insertion-order-preserving characteristics of a List, you could consider a java.util.concurrent.ConcurrentLinkedQueue. Since it implements Iterable, once you've finished adding all the items, yo...
Is there a combination of “LIKE” and “IN” in SQL?
In SQL I (sadly) often have to use " LIKE " conditions due to databases that violate nearly every rule of normalization. I can't change that right now. But that's irrelevant to the question.
...
Scala: What is a TypeTag and how do I use it?
...ixes that come from different mirrors), 2) Both TypeTag and AbsTypeTag are based on mirrors. The difference is that TypeTag only allows fully instantiated types (i.e. without any type parameters or references abstract type members), 3) A detailed explanation is here: stackoverflow.com/questions/1209...