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How is this fibonacci-function memoized?
...is asked for again. If we define some list, xs=[0..] and later ask for its 100th element, xs!!99, the 100th slot in the list gets "fleshed out", holding the number 99 now, ready for next access.
That is what that trick, "going-through-a-list", is exploiting. In normal doubly-recursve Fibonacci def...
In javascript, is an empty string always false as a boolean?
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196
Yes. Javascript is a dialect of ECMAScript, and ECMAScript language specification clearly defi...
How to redirect the output of an application in background to /dev/null
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231
You use:
yourcommand > /dev/null 2>&1
If it should run in the Background add an &...
How to make a div grow in height while having floats inside
...er div fully wraps around them. See this example:
.wrap {
padding: 1em;
overflow: auto;
background: silver;
}
.float {
float: left;
width: 40%;
background: white;
margin: 0 1%;
}
<div class="wrap">
<div class="float">Cras mattis iudicium purus sit ame...
How do I retrieve the number of columns in a Pandas data frame?
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312
Like so:
import pandas as pd
df = pd.DataFrame({"pear": [1,2,3], "apple": [2,3,4], "orange": [...
Entity Framework - Add Navigation Property Manually
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181
Yup - it's not that straightforward.
Here's what you do:
1 - Right click on the designer, Ad...
How can I filter lines on load in Pandas read_csv function?
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170
There isn't an option to filter the rows before the CSV file is loaded into a pandas object.
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What are the best practices for catching and re-throwing exceptions?
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edited Feb 9 '15 at 18:06
answered Apr 5 '11 at 12:31
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How to check if variable's type matches Type stored in a variable
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195
The other answers all contain significant omissions.
The is operator does not check if the ru...
Why doesn't c++ have &&= or ||= for booleans?
...alent to the logical operations, as long as both operands are of type bool.1
Contrary to what other people have said here, a bool in C++ must never have a different value such as 2. When assigning that value to a bool, it will be converted to true as per the standard.
The only way to get an invali...