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How to add column if not exists on PostgreSQL?
...statement:
DO $$
BEGIN
BEGIN
ALTER TABLE <table_name> ADD COLUMN <column_name> <column_type>;
EXCEPTION
WHEN duplicate_column THEN RAISE NOTICE 'column <column_name> already exists in <table_name>.';
END;
END;
$$
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Tree data structure in C#
...e so many ways you could implement it that it would be impossible to cover all bases with one solution. The more specific a solution, the less likely it is applicable to any given problem. I even get annoyed with LinkedList - what if I want a circular linked list?
The basic structure you'll need ...
What is the difference between class and instance attributes?
...just look in each instance's __dict__ and the class's __dict__. It just usually doesn't matter very much whether immutable types are shared or not.
– abarnert
Oct 29 '14 at 22:58
1...
How to programmatically send a 404 response with Express/Node?
...on for this on the response object. Just chain it in somewhere before you call send.
res.status(404) // HTTP status 404: NotFound
.send('Not found');
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Show all Elasticsearch aggregation results/buckets and not just 10
I'm trying to list all buckets on an aggregation, but it seems to be showing only the first 10.
4 Answers
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Extract elements of list at odd positions
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Solution
Yes, you can:
l = L[1::2]
And this is all. The result will contain the elements placed on the following positions (0-based, so first element is at position 0, second at 1 etc.):
1, 3, 5
so the result (actual numbers) will be:
2, 4, 6
Explanation
The [1::2]...
Getting LaTeX into R Plots
...t interferes with the ggplot ~ # tikzDecice combo
colnames(AR) <- c("$V_{BB}[V]$", "$V_{RB}[V]$" , "$V_{RC}[V]$" , "$I_B[\\mu A]$" , "IC" , "$V_{BE}[V]$" , "$V_{CE}[V]$" , "beta" , "$I_E[mA]$")
# make sure the working directory is where you want your tikz file to go
setwd("~/TexImageFolder/")
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Javascript: Round up to the next multiple of 5
...
const fn = _num =>{
return Math.round(_num)+ (5 -(Math.round(_num)%5))
}
reason for using round is that expected input can be a random number.
Thanks!!!
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What can you do in MSIL that you cannot do in C# or VB.NET? [closed]
All code written in .NET languages compiles to MSIL, but are there specific tasks / operations that you can do only using MSIL directly?
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Removing duplicates from a list of lists
... much easier that it offers good returns on efforts. But sometimes (essentially for "tragically crucial bottlenecks" in deep inner loops of code that's pushing the boundaries of performance limits) one may need to go into much more detail, providing probability distributions, deciding which performa...