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Is Ruby pass by reference or by value?
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Ruby is pass-by-value. No ifs. No buts. No exceptions. If you want to know whether Ruby (or any other language) is pass-by-reference or pass-by-value, just try it out: def foo(bar) bar = 'reference' end; baz = 'value'; foo(baz); puts "Ruby is pass-by-#{baz}".
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Does Haskell require a garbage collector?
...grams, the lifetime of an object can only be determined at runtime.
For example, consider the following program:
main = loop (Just [1..1000]) where
loop :: Maybe [Int] -> IO ()
loop obj = do
print obj
resp <- getLine
if resp == "clear"
then loop Nothing
else loop o...
Java Name Hiding: The Hard Way
I have a problem with name hiding that is extremely hard to solve. Here is a simplified version that explains the problem:
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What is the difference between a string and a byte string?
...t encoding may map the same bytes to a different string:
>>> b'\xcf\x84o\xcf\x81\xce\xbdo\xcf\x82'.decode('utf-16')
'蓏콯캁澽苏'
>>> b'\xcf\x84o\xcf\x81\xce\xbdo\xcf\x82'.decode('utf-8')
'τoρνoς'
Once you know which one to use, you can use the .decode() method of the b...
Opposite of %in%: exclude rows with values specified in a vector
...presented by the letters from A to Z. I want to create a subset D2, which excludes some values, say, B, N and T. Basically, I want a command which is the opposite of %in%
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What exactly does an #if 0 … #endif block do?
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Not only does it not get executed, it doesn't even get compiled.
#if is a preprocessor command, which gets evaluated before the actual compilation step. The code inside that block doesn't appear in the compiled binary.
It's often used for temporaril...
“Variable” variables in Javascript?
I know it's possible in PHP to have "variable" variables. For example
7 Answers
7
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How do I get the row count of a pandas DataFrame?
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You can use the .shape property or just len(DataFrame.index). However, there are notable performance differences ( len(DataFrame.index) is fastest).
Code to reproduce the plot:
import numpy as np
import pandas as pd
import perfplot
perfplot.save(
"out.png",
setup=lambda ...
How to invoke the super constructor in Python?
...structor is invoked implicitly. How does one invoke it in Python? I would expect super(self) but this doesn't work.
7 Ans...
ImportError: Cannot import name X
...ld know that two classes should NEVER be dependant on each other. This is extremely important in C++, and even if it's not the #1 thing in Python, it's still a really good idea to follow this rule. Never have two classes which know each other, ever. If you need help with creating the structure for y...