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Transposing a NumPy array
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It's working exactly as it's supposed to. The transpose of a 1D array is still a 1D array! (If you're used to matlab, it fundamentally doesn't have a concept of a 1D array. Matlab's "1D" arrays are 2D.)
If you want to turn your 1D vector...
Creating dataframe from a dictionary where entries have different lengths
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In Python 3.x:
import pandas as pd
import numpy as np
d = dict( A = np.array([1,2]), B = np.array([1,2,3,4]) )
pd.DataFrame(dict([ (k,pd.Series(v)) for k,v in d.items() ]))
Out[7]:
A B
0 1 1
1 2 2
2 NaN 3
3 NaN 4
In...
Homebrew’s `git` not using completion
When using OSX’s git, after I modify a file I can simply do git commit <tab> , and that’ll auto complete the file’s name to the one that was modified. However, if I install a newer version of git from homebrew and I use it, that feature no longer works (meaning I press <tab> and...
Why is a round-trip conversion via a string not safe for a double?
Recently I have had to serialize a double into text, and then get it back. The value seems to not be equivalent:
3 Answers
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How to manually expand a special variable (ex: ~ tilde) in bash
...urposes (but please don't use this)
If I'm not mistaken, "~" will not be expanded by a bash script in that manner because it is treated as a literal string "~". You can force expansion via eval like this.
#!/bin/bash
homedir=~
eval homedir=$homedir
echo $homedir # prints home path
Alternatively...
ReSharper warns: “Static field in generic type”
...that R# is just warning you in case you weren't aware of that.
Here's an example of that:
using System;
public class Generic<T>
{
// Of course we wouldn't normally have public fields, but...
public static int Foo;
}
public class Test
{
public static void Main()
{
Ge...
Overloading and overriding
...o override else you'll get a compilation error.
– Alex Stephens
May 21 '15 at 18:38
Hey, this might be old but I still...
Read a variable in bash with a default value
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You can use parameter expansion, e.g.
read -p "Enter your name [Richard]: " name
name=${name:-Richard}
echo $name
Including the default value in the prompt between brackets is a fairly common convention
What does the :-Richard part do? From the ba...
Java how to replace 2 or more spaces with single space in string and delete leading and trailing spa
...opy of the string, with leading and trailing whitespace omitted.
regular-expressions.info/Repetition
No trim() regex
It's also possible to do this with just one replaceAll, but this is much less readable than the trim() solution. Nonetheless, it's provided here just to show what regex can do:
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Undefined, unspecified and implementation-defined behavior
...pilers will not report any errors in the program!
Let's look at a classic example:
#include <iostream>
int main()
{
char* p = "hello!\n"; // yes I know, deprecated conversion
p[0] = 'y';
p[5] = 'w';
std::cout << p;
}
The variable p points to the string literal "hello!...