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How do you get the magnitude of a vector in Numpy?
...ray -- say x.norm() -- but oh well).
import numpy as np
x = np.array([1,2,3,4,5])
np.linalg.norm(x)
You can also feed in an optional ord for the nth order norm you want. Say you wanted the 1-norm:
np.linalg.norm(x,ord=1)
And so on.
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jQuery select by attribute using AND and OR operators
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AND operation
a=$('[myc="blue"][myid="1"][myid="3"]');
OR operation, use commas
a=$('[myc="blue"],[myid="1"],[myid="3"]');
As @Vega commented:
a=$('[myc="blue"][myid="1"],[myc="blue"][myid="3"]');
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The $.param( ) inverse function in JavaScript / jQuery
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answered Jun 9 '11 at 19:23
ccecce
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How to delete multiple values from a vector?
...vector like: a = c(1:10) and I need to remove multiple values, like: 2, 3, 5
8 Answers
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Compare two data.frames to find the rows in data.frame 1 that are not present in data.frame 2
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13 Answers
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How to concatenate twice with the C preprocessor and expand a macro as in “arg ## _ ## MACRO”?
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Standard C Preprocessor
$ cat xx.c
#define VARIABLE 3
#define PASTER(x,y) x ## _ ## y
#define EVALUATOR(x,y) PASTER(x,y)
#define NAME(fun) EVALUATOR(fun, VARIABLE)
extern void NAME(mine)(char *x);
$ gcc -E xx.c
# 1 "xx.c"
# 1 "<built-in>"
# 1 "<command-line>"
# 1...
Split comma-separated strings in a column into separate rows
...th more than about 5000 rows, Jaap's data.table method 2 and the variant DT3 are the fastest, magnitudes faster than the slowest methods.
Remarkably, the timings of the two tidyverse methods and the splistackshape solution are so similar that it's difficult to distiguish the curves in the chart. T...
What's the difference between RANK() and DENSE_RANK() functions in oracle?
... assigned the same rank, with the next ranking(s) skipped. So, if you have 3 items at rank 2, the next rank listed would be ranked 5.
DENSE_RANK again gives you the ranking within your ordered partition, but the ranks are consecutive. No ranks are skipped if there are ranks with multiple items.
As...
Find integer index of rows with NaN in pandas dataframe
...n use to index back into df, e.g.:
df['a'].ix[index[0]]
>>> 1.452354
For the integer index:
df_index = df.index.values.tolist()
[df_index.index(i) for i in index]
>>> [3, 6]
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What is an alternative to execfile in Python 3?
It seems they canceled in Python 3 all the easy way to quickly load a script by removing execfile()
12 Answers
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