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What are the use cases for selecting CHAR over VARCHAR in SQL?
...the word "FooBar"
CHAR(6) = 6 bytes (no overhead)
VARCHAR(100) = 8 bytes (2 bytes of overhead)
CHAR(10) = 10 bytes (4 bytes of waste)
The bottom line is CHAR can be faster and more space-efficient for data of relatively the same length (within two characters length difference).
Note: Microsoft SQL...
super() raises “TypeError: must be type, not classobj” for new-style class
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246
Alright, it's the usual "super() cannot be used with an old-style class".
However, the import...
View a list of recent documents in Vim
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203
Don't use a plugin, unless you want a nice menu. From Vim Documentation: Starting (or :help ol...
What is the easiest way to get current GMT time in Unix timestamp format?
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246
I would use time.time() to get a timestamp in seconds since the epoch.
import time
time.time...
How to convert a JSON string to a Map with Jackson JSON
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325
[Update Sept 2020] Although my original answer here, from many years ago, seems to be helpful a...
How can I make space between two buttons in same div?
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12 Answers
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Constructing pandas DataFrame from values in variables gives “ValueError: If using all scalar values
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621
The error message says that if you're passing scalar values, you have to pass an index. So you...
HashSet vs LinkedHashSet
...public LinkedHashSet(Collection<? extends E> c) {
super(Math.max(2*c.size(), 11), .75f, true); // <-- boolean dummy argument
addAll(c);
}
And (one example of) a HashSet constructor that takes a boolean argument is described, and looks like this:
/**
* Constructs a new, empty l...
How to parse/read a YAML file into a Python object? [duplicate]
... name: Node 1
branch1-1:
name: Node 1-1
branch2:
name: Node 2
branch2-1:
name: Node 2-1
And you've installed PyYAML like this:
pip install PyYAML
And the Python code looks like this:
import yaml
with open('tree.yaml') as f:
# use saf...
Check if value already exists within list of dictionaries?
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273
Here's one way to do it:
if not any(d['main_color'] == 'red' for d in a):
# does not exist...