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How are multi-dimensional arrays formatted in memory?
...things are going to happen. Here's a quick example:
int array1[3][2] = {{0, 1}, {2, 3}, {4, 5}};
In memory looks like this:
0 1 2 3 4 5
exactly the same as:
int array2[6] = { 0, 1, 2, 3, 4, 5 };
But if you try to pass array1 to this function:
void function1(int **a);
you'll get a warnin...
python plot normal distribution
...ot as plt
import numpy as np
import scipy.stats as stats
import math
mu = 0
variance = 1
sigma = math.sqrt(variance)
x = np.linspace(mu - 3*sigma, mu + 3*sigma, 100)
plt.plot(x, stats.norm.pdf(x, mu, sigma))
plt.show()
s...
Add single element to array in numpy
...mal to use the proper method for adding an element:
a = numpy.append(a, a[0])
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Adding an arbitrary line to a matplotlib plot in ipython notebook
...as np
import matplotlib.pyplot as plt
np.random.seed(5)
x = np.arange(1, 101)
y = 20 + 3 * x + np.random.normal(0, 60, 100)
plt.plot(x, y, "o")
# draw vertical line from (70,100) to (70, 250)
plt.plot([70, 70], [100, 250], 'k-', lw=2)
# draw diagonal line from (70, 90) to (90, 200)
plt.plot([70,...
[] and {} vs list() and dict(), which is better?
...s/dicts:
>>> from timeit import timeit
>>> timeit("[]")
0.040084982867934334
>>> timeit("list()")
0.17704233359267718
>>> timeit("{}")
0.033620194745424214
>>> timeit("dict()")
0.1821558326547077
and for non-empty:
>>> timeit("[1,2,3]")
0.243...
Detail change after Git pull
...
209
Suppose you're pulling to master. You can refer to the previous position of master by master@{1...
Removing leading zeroes from a field in a SQL statement
...ve the leading zeroes from a particular field, which is a simple VARCHAR(10) field. So, for example, if the field contains '00001A', the SELECT statement needs to return the data as '1A'.
...
surface plots in matplotlib
...t.figure()
ax = fig.add_subplot(111, projection='3d')
x = y = np.arange(-3.0, 3.0, 0.05)
X, Y = np.meshgrid(x, y)
zs = np.array(fun(np.ravel(X), np.ravel(Y)))
Z = zs.reshape(X.shape)
ax.plot_surface(X, Y, Z)
ax.set_xlabel('X Label')
ax.set_ylabel('Y Label')
ax.set_zlabel('Z Label')
plt.show()
...
How to initialize all members of an array to the same value?
...
Unless that value is 0 (in which case you can omit some part of the initializer
and the corresponding elements will be initialized to 0), there's no easy way.
Don't overlook the obvious solution, though:
int myArray[10] = { 5, 5, 5, 5, 5, 5, 5,...
Get loop count inside a Python FOR loop
...
605
The pythonic way is to use enumerate:
for idx,item in enumerate(list):
...