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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...
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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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 ...
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
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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.
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How to change the type of a field?
... @SundarBons yes you are re-writing a field across your database, this is a big deal no matter how you do it. If you were using SQL and this was a big table you would probably have to take some down time.
– Gates VP
Jun 28 '16 at 18:16
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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
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Is there a concurrent List in Java's JDK?
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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.
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