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Questions tagged [counting]

Questions on counting subparts of expressions, based on certain criteria. This is to be used with primary tags such as list-manipulation or string-manipulation, with the primary tag indicating the specific use case.

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84 views

Fast way to count distinct pairs of integers

I have a association list, S, whose size is about 5*10^4. I also have a function F which takes in ordered pairs of elements from S, and spits out ordered pairs of integers. There is some amount of ...
26 views

How to count n observations/ rows in a table?

What is the expression to count the rows/ observations? This is how I entered data: ...
52 views

Counting the number of strings starting with “t” and containing 2 vowels and 2 consonants

I generated a list of strings that match the criteria in the title as follows: ...
390 views

Count number of occurences of particular numbers in list

I have a list of numbers which I have rounded and now all numbers are divisible by 5. ...
53 views

Making polynomials representing frequency of a character in a list

Suppose I have the following list: l={{"a"}, {"a", "h"}, {"a", "d", "k", "r", "v"}, {"a", "b", "c", "k"}, {"a", "b", "c", "s", "u"}} this list made of the ...
308 views

How can I get the count of how many times a string appears in my list? [closed]

I have a list of strings, like so: {"aa bb", "cc dd", "aa bb", "aa bb", "cc dd", "ww ss", "ss ss", "kk mm"} I know WordCounts ...
87 views

How to creates a Counts[] function that includes zero?

In the following example, I'm trying to how many times each integer 1-n appears in list 'a'. But if an element did not appear in a list, Counts[] creates an association that returns the element ...
49 views

Count sublists containing certain strings

I have a nested list which looks like: and I would like to count the following: all sublists containing {n_,n_} && {n_,n_,n_} all sublists containing {l_,l_} && {l_,l_,l_} all ...
55 views

Counting the number of Configurations in an Array with Constraints

Consider an array $$\{a_i\}, i=1, ..., N$$ with periodic boundary condition, i.e. $i\equiv i+N$. $a_i\in \{0, 1\}$. I would like to count the number of configurations of the array $\{a_i\}$ satisfying ...
472 views

Loop over a list of strings and increment letter count in a corresponding sublist

I have a 2D list as follows: ...
49 views

Bin arbitrary data using canonical ordering

I have two lists of words, nouns and verbs: ...
288 views

Bigrams and TF-IDF calculation

I want to create a bag of bigrams in a set of documents and calculate the TF-IDF vector of each document. To calculate the bigram of the text I used the following code: The small example of the data (...
216 views

How to count the number of eggshells in the image

My goal for this is to simply count the number of eggshells in the image. Using color negate only leads to this ...
171 views

How can one efficiently find the (x,y) values of the rectangles that enclose a chosen % of nonrandom data points in mathematica?

A half hour of searching for answers did not give useful results. This is typical data: I need to find the (x,y) values of at least 6 rectangles with one corner at (0,0) and the opposite corner at (...
207 views

How many records? In a file (streaming)

I want to know how many records a file (large data) contains... with streaming...like this: ...
58 views

Counting all matrices in a family obeying a certain rule

I would like to use the Count[list, pattern] method to count all 4x4 matrices with entries in $\lbrace 0 ,1 \rbrace$ that have a certain Jordan canonical form. The ...
94 views

Probability of empty urns for undistinguishable balls in distinguishable urns

Distinguishable balls in distinguishable urns is a well known problem in probability theory and can be easily simulated through Montecarlo simulations. Here we provide our code for n balls and m urns: ...
697 views

How to total the amount of zeros in a binary matrix

I have a 150 by 300 binary matrix. I would like to find the total amount of zeros in the matrix. I've been consulting online documentation for support, but am unable to use the "count" function ...
201 views

Count does not tally with total

I code the following to count events. Count[Table[RandomInteger[{1, 6}], {i, 10}], #] & /@ Range//Total By right, if I total, I expect 10. Sometimes it ...
179 views

Most common prefixes in an English corpus (Hamlet)

There are many resources online showing how to get the most frequent letters in the english language. What I'm trying to do is get the most common word prefixes in the english language - i.e, take a ...
209 views

Count Column Elements in a Matrix [duplicate]

Let a square matrix be: mat={{1,2,3},{4,5,6},{0,0,0}}; Get a total for each column: In: Total[mat] ...
112 views

Counting number of spheres that contain a point

I have created this set of spheres in Mathematica. The code I used to produced this is as follows: ...
157 views

Weibull Count Process, how to build in Mathematica

I am trying to solve the following problem in MATHEMATICA: (PROBLEM SOLVED, LOOK THE FOLLOWING ANSWER) I was reading this paper: McShane et al. "Count Models Based on Weibull Interarrival Times" (...
132 views

Finding the number of $4$-tuples of consisting of digits $1$-$6$ satisfying a certain condition

I'm trying to enumerate a sample space for an experiment in which $4$ fair $6$-sided dice are rolled such that exactly $3$ of them are $5$s or $6$s. The way I understand it, the last die must be any ...
136 views

Opposite of Counts

I would like to reverse the effect of Counts, i.e., starting with x = <|a -> 4, b -> 2, c -> 1|> I would like ...
54 views

Number of different terms inside mathematical expression

I have expressions of the form $OpA[x\_,y\_]$ and $OpB[x\_,y\_]$ ocurring inside mathematical expressions. I want to create a function which does the following: ...
20 views

Count cases of number [duplicate]

h = {140, 140, 175, 160, 175, 125, 120, 105, 15, 90, 150, 175, 85, 110, 30, 60, 175, 50, 130, 70, 60, 40, 130, 135, 120, 110, 150, 110, 175, 70} I have a list of ...
71 views

Mathematica functions for dealing with sets of integers [closed]

What are the convenient Mathematica functions, say $Func1$ and $Func2$, that if one inputs a collection of sets of numbers: $$\text{{{1,2},{3,2},{4,1},{1,2},{1,2},{4,1}}}$$ (1) \text{$Func1$[{{1,...
186 views

find and count the number of solutions without multiplicity in Solve?

I would like to solve a Diophantine equation and find its solution, but I need only count one time for each $a$, i.e., when for some $a$ it found some $x,y,z$, then go to the next $a$. more precisely ...
85 views

Repeated consecutive values above a threshold

I would like to know if a list has repeated consecutive values above a threshold. Lets say for this example the threshold is 5. ...
99 views

Counts[list] giving unexpected result [closed]

I import some data from an .xls-file and process it by subtracting pairs of data. What I need to do is counting the total number of each difference appearing in my result list, e.g. if the result list ...
148 views

Count gives different results depending on specification

I have a tremendous list of coordinates in which i wish to count how many times a certain X appears. I use count and found accidentally, that in a loop script and individually, it gives wrong results ...
280 views

Determine the number of times a function will be called

I have a function func[x], which is rather slow to evaluate. It gets called (multiple times) inside other expressions; I'd like to know how many times it gets called (without actually evaluating the ...
108 views

How do I count the TOTAL number of “Subsection” cells in a notebook externally?

I can count the number of "Subsection" cells in a notebook by evaluating the following code at the BOTTOM of the notebook. ...
982 views

Determine repeating number of a given number and corresponding position

For instance, the data is as follows: data = {1, 1, 1, -1, -1, 1, 1, -1} The target output when determining how many times "1"...
128 views

Counting the rows of a list where the order of numbers in the row doesn't matter

I am trying to make a computation with a large set of rows. As a sample, suppose I have a list of numbers with rows and columns like such: ...
37 views

How to renew a value when a value is larger than it, counting the time of the record being broken at the same time [duplicate]

I have a given value and is it possible that after some calculation, when the calculated result is larger than the given value, the given value can be set as the value that is larger than it? Other ...
147 views

How to make my fuction return a step count

I am new to mathematica, and I have this 3d random walker program which runs with a fixed (given) amount of steps. What I want it to do is to run forever but stop when two walkers collide (aka have ...
220 views

How to make CounterIncrement step in increments of 2

Is it possible to make counters that step in increments other than 1? The default for CounterIncrements seems to be 1 and there's no other documentation on what ...
78 views

Using a prompt to set options

I am creating a toolbar. One of the buttons on my toolbar is this setcounter button below. ...
4k views

How to count number of small dots in a picture

I have this picture of small particles in a polymer film. I want to count how many particles in the figure, so that I can have a rough estimation of the particle density. But the image quality is poor,...
271 views

Best way to count this?

I'm trying to use the Count function for this purpose, but it's not working how I'd like it to. Does anybody know a simple way to do this counting? I would like to be counting the number of "p"s in ...
100 views

Length of a disjunction

Simple question: I'm trying to count the number of Roots to an equation. But both Length[x==1] and ...
307 views

Optimal Binarize value for counting experiment

I am currently working on a physics experiment where I count particles. I have looked at and used a bit of code from the following sources: Cell counting from an image file and Count Elements in Image ...
448 views

Count two or more equal consecutive elements in a list and create histogram

I have a list generated by: list = RandomInteger[{1}, 100] it contains only 0's and 1's ...
489 views

Count the number of regions made by Lissajous curve

How many disconnected regions does Lissajous curve divide the plane into? For example: Let g = ParametricPlot[{Sin[2 t], Sin[t]}, {t, 0, 2 π}] The number of ...
2k views

Count elements of a list

Let's create a random list n = 100; data = Table[{RandomReal[{0, 2}], RandomReal[{-1, 1}]}, {i, 0, n}] Now we divide the $(x,y)$ plane into four sectors with the ...
97 views

Transform List from {a,a,b,b,b,c} to {{a,2},{b,3},{c,1}} [closed]

The title pretty much says it. I want to map over the solutions returned by Solve but want to avoid calculating the same thing over and over again. e.g. ...