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How do write IF ELSE statement in a MySQL query
...
150
You probably want to use a CASE expression.
They look like this:
SELECT col1, col2, (case wh...
pyplot scatter plot marker size
...d the output they produce.
# doubling the width of markers
x = [0,2,4,6,8,10]
y = [0]*len(x)
s = [20*4**n for n in range(len(x))]
plt.scatter(x,y,s=s)
plt.show()
gives
Notice how the size increases very quickly. If instead we have
# doubling the area of markers
x = [0,2,4,6,8,10]
y = [0]*len(...
Git Extensions: Win32 error 487: Couldn't reserve space for cygwin's heap, Win32 error 0
...
14 Answers
14
Active
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How many double numbers are there between 0.0 and 1.0?
...or example, that's the number of distinct doubles between 0.5 included and 1.0 excluded, and exactly that many also lie between 1.0 included and 2.0 excluded, and so forth.
Counting the doubles between 0.0 and 1.0 is harder than doing so between powers of two, because there are many powers of two i...
How to map atan2() to degrees 0-360
atan2(y, x) has that discontinuity at 180° where it switches to -180°..0° going clockwise.
15 Answers
...
All falsey values in JavaScript
...ypeof as undefined. It was a Microsoft-proprietory function in IE before IE11, and was added to the HTML spec as a "willful violation of the JavaScript specification" so that sites written for IE wouldn't break on trying to access, for example, document.all.something; it's falsy because if (document...
How to catch integer(0)?
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164
That is R's way of printing a zero length vector (an integer one), so you could test for a bei...
Find the max of two or more columns with pandas
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185
You can get the maximum like this:
>>> import pandas as pd
>>> df = pd.Data...
Sort a list by multiple attributes?
... can be a function that returns a tuple:
s = sorted(s, key = lambda x: (x[1], x[2]))
Or you can achieve the same using itemgetter (which is faster and avoids a Python function call):
import operator
s = sorted(s, key = operator.itemgetter(1, 2))
And notice that here you can use sort instead of...
Regular expressions in C: examples?
...s):
#include <regex.h>
regex_t regex;
int reti;
char msgbuf[100];
/* Compile regular expression */
reti = regcomp(&regex, "^a[[:alnum:]]", 0);
if (reti) {
fprintf(stderr, "Could not compile regex\n");
exit(1);
}
/* Execute regular expression */
reti = regexec(&regex,...