================================== Top new questions this week: ==================================
[How to sort digits in a string while keeping other characters untouched?] http://mathematica.stackexchange.com/questions/78464/how-to-sort-digits-in-a-string-while-keeping-other-characters-untouched
Now there is a string with digits and letters, for instance, "95uge678r3gi89hgfe30kgh063d51". And the expected output is "00uge133r3gi55hgfe66kgh788d99".
I am able to do it in this way
...
- asked by Felix (12 votes), answered by Mr.Wizard (8 votes)
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[Expansion of a hypergeometric function takes ages with Mathematica 9 and 10 (regression?)] http://mathematica.stackexchange.com/questions/78534/expansion-of-a-hypergeometric-function-takes-ages-with-mathematica-9-and-10-reg
Mathematica 8 (Linux version) can evaluate
AbsoluteTiming[Series[Hypergeometric2F1[1, 1 - eps/2, 3 - eps, 1/2], eps, 0, 0]]
in no time. On one of the university machines the result is
0.175840, ...
- asked by vsht (10 votes), answered by Eric Towers (4 votes)
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[Opposite of StringSplit]http://mathematica.stackexchange.com/questions/78405/opposite-of-stringsplit
What is an appropriate command that does the opposite of the following.
StringSplit["a b c d e f g"," "]
- asked by William (10 votes), answered by Pickett (16 votes)
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[Why can I not replace a Dataset using a rule?]http://mathematica.stackexchange.com/questions/78131/why-can-i-not-replace-a-dataset-using-a-rule
Simple replacement of a Dataset object does not seem to follow the expected behavior...
Dataset[{}] /. _Dataset->1
Returns the empty Dataset not 1 as I would have expected.
Whereas...
- asked by Ymareth (9 votes), answered by WReach (11 votes)
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[Turning a set of random walk data 45 degrees] http://mathematica.stackexchange.com/questions/78347/turning-a-set-of-random-walk-data-45-degrees
I have a set of data that is just a "random" (generated by me, not by computer) sequence of length 2000 of 1’s and (-1)’s. I used it to plot a 1-D random walk where +1 is step up, (-1) is step down, ...
- asked by Solarmew (8 votes), answered by Karsten 7. (4 votes)
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[Unexpected slowness checking for empty list?] http://mathematica.stackexchange.com/questions/78155/unexpected-slowness-checking-for-empty-list
I thought I had a firm understanding of the differences between Equal and SameQ, but this has me puzzled:
test = RandomInteger[100000000, 10000000]; == test // AbsoluteTiming === test // ...
- asked by rasher (8 votes), answered by Mr.Wizard (9 votes)
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[Mathematica on Raspberry Pi] http://mathematica.stackexchange.com/questions/78319/mathematica-on-raspberry-pi
Can I develop BSD/MIT open-source library for Mathematica using free non-commercial version on Raspberry Pi?
To state it differently: does the non-commercial limitation of Mathematica on RPi limit ...
- asked by denfromufa (7 votes), answered by denfromufa (3 votes)
================================== Greatest hits from previous weeks: ==================================
[Divide all but the maximal element in a list by 10?]http://mathematica.stackexchange.com/questions/69547/divide-all-but-the-maximal-element-in-a-list-by-10
I have a list of numerical data, and I want to write a program that will keep the maximum as it is, but reduce the rest by certain factor (such as 10). For example:
input = 2, 3, 1, -3, -5, 9, 2, 6, ...
- asked by Paul (13 votes), answered by WReach (20 votes)
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[Division by zero is slow]http://mathematica.stackexchange.com/questions/64247/division-by-zero-is-slow
Suppose I have two arrays of data, which I want to divide:
n = 1000; a = RandomInteger[1, 9, n, n]; b = RandomInteger[1, 9, n, n]; First @ AbsoluteTiming @ (a/b)
0.637064
But suppose ...
- asked by wxffles (12 votes), answered by Michael E2 (6 votes)
================================== Can you answer these? ==================================
[Display of ConfusionMatrixPlot depends on Stylesheet] http://mathematica.stackexchange.com/questions/78229/display-of-confusionmatrixplot-depends-on-stylesheet
I’m using Classify and do the testing via ClassifierMeasurements. Now I observed that ConfusionMatrixPlot is not shown correctly when using StyleSheet Report(default). Maybe you can reproduce (example ...
- asked by mgamer (2 votes)
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[How to restart a Clock] http://mathematica.stackexchange.com/questions/78677/how-to-restart-a-clock
The code below is to demonstrate color afterimages. The user chooses a color, fixates the changing numbers at the center until they reach 30 (seconds), then manually switches to white to observer the ...
- asked by abwatson (1 vote)
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[NDSolve Poisson PDE for rectangle with hole] http://mathematica.stackexchange.com/questions/78624/ndsolve-poisson-pde-for-rectangle-with-hole
When I solved the Poisson PDE with function NDSolve in a rectangular domain with hole in the center, and search the first derivative with x and y why appear these protrusions on the diagram around the ...
- asked by wlkyr (1 vote)