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How do I declare a 2d array in C++ using new?
...f T" and be an incomplete type, while T[][] would be an invalid type (all except the last dimensions must have a known size). T[N][M] is "array [N] of array[M] of T", while yours, T[sizeX] is "array [sizeX] of T" where T is a pointer to an int. Creating a dynamically 2d array works like this: new in...
How do lexical closures work?
While I was investigating a problem I had with lexical closures in Javascript code, I came along this problem in Python:
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Why use pointers? [closed]
...re you cannot use anything else. In C you don't have any support for complex datatypes such as a string. There are also no way of passing a variable "by reference" to a function. That's where you have to use pointers. Also you can have them to point at virtually anything, linked lists, members of st...
How to scale down a range of numbers with a known min and max value
... to be in a range of say 1-30. I have methods that find the minimum and maximum values from my data set, but I won't have the min and max until runtime. Is there an easy way to do this?
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C# Convert List to Dictionary
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Try this:
var res = list.ToDictionary(x => x, x => x);
The first lambda lets you pick the key, the second one picks the value.
You can play with it and make values differ from the keys, like this:
var res = list.ToDictionary(x => x, x => string.Fo...
Using @property versus getters and setters
...ut hiding slow methods behind a @property decorator. The user of your API expects that property access performs like variable access, and straying too far away from that expectation can make your API unpleasant to use.
– defrex
Feb 25 '14 at 17:21
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sql ORDER BY multiple values in specific order?
Ok I have a table with a indexed key and a non indexed field.
I need to find all records with a certain value and return the row.
I would like to know if I can order by multiple values.
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Get list from pandas DataFrame column headers
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I would have expect something like df.column_names(). Is this answer still right or is it outdated?
– alvas
Jan 13 '16 at 6:48
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How to convert an array of strings to an array of floats in numpy?
...array of strings, there's a better way. Use astype().
import numpy as np
x = np.array(['1.1', '2.2', '3.3'])
y = x.astype(np.float)
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Matplotlib discrete colorbar
...As an alternative you can make your own cmap from scratch, or read-out an existing one and override just some specific entries.
import numpy as np
import matplotlib as mpl
import matplotlib.pylab as plt
fig, ax = plt.subplots(1, 1, figsize=(6, 6)) # setup the plot
x = np.random.rand(20) # defin...