6
votes
5answers
274 views

Find patterns in a list

again, I have a list like this: ...
1
vote
4answers
162 views

Need an efficient way to do this list manipulation

Lets say i have two lists with me as given below: l1 = {4, 6, 8, 9, 10, 12}; l2 = {2, 3, 4, 5, 6, 7}; Now i have a function S2P(details irrelevant) which takes ...
2
votes
2answers
122 views
4
votes
2answers
134 views

Get part of lousy data

I want to get part of large data. some part of this data is as follows: ...
5
votes
1answer
224 views

More efficient Omnibus number determination?

Amusing myself with concepts from "Omnibus Sequences, Coupon Collection, and Missing Word Counts", in particular the sequences. To paraphrase the concept, a string is k-Omni over some alphabet a if ...
0
votes
1answer
71 views

Sum similar elements [closed]

I am interested in summing elements in a list or sublist that are similar. I want the sublists of my second elements to be added cumulatively only if their first elements are the same. This is my ...
1
vote
1answer
85 views

Matching variables with Subscripts yielding True and False

I am trying match variables with subscripts just returning true or false depending if pattern is matched. My try is to use Cases. However the following does not ...
2
votes
2answers
172 views

Removing trailing zeros from a list

If I have a list like list1={2334.,342.,0.,0.,2322.,0.,0.,0.,0.,,,,,,}; it's easy to remove to trailing blanks with ...
2
votes
4answers
494 views

More elegant way

I read ReplaceOrRemoveInvalidOrMissingData Mathematica documentation, and I tried to apply the same approach to my dataset. I've got two problems, but one is only a style problem! There is one more ...
1
vote
3answers
81 views
12
votes
4answers
339 views

How to enumerate all possible binary associations?

Suppose I have a list of symbols like: {a,b,c,d} I would like to enumerate all possible binary associations (combining symbols and/or sublists pairwise): ...
3
votes
4answers
188 views

Pattern matching in nested lists

I'm sure this has been asked before, but I can't find the right combination of search keywords to find it. Apologies. I want to do a ReplaceAll on a list of lists, ...
6
votes
3answers
164 views

Using PatternTest and/or Condition to detect equal list lengths as well as list element formats

On searching Mathematica.SE for information about overloading functions, I came across several threads about PatternTest and ...
12
votes
10answers
659 views

Counting sublists containing 0

Given a list: data = {{0, 2}, {0, 0}, {1, 0}, {1, 2}, {2, 3}}. I would like to count the number of sublists which contain zero. ...
2
votes
3answers
301 views

Select sublists with second element nearest to zero

I've got some big lists from which i need some data (one of the big lists). To be specific, I need to divide this biglists in sublists of the same length (10000), and form a new list with the mean of ...
8
votes
3answers
191 views

Select and Blank

I try to filter sublists of a list which match a pattern. test = {{"String1", "a"}, {"String2", "b"}, {"String3", "a"}, {"String4", "a"}}; The result should ...
2
votes
1answer
125 views

Match a sequence of integers

I would to match a pattern p1 = 0,0,1,0,0 to the elements in listA. The elements are a boolean sequence that may look like this ...
4
votes
4answers
341 views

Listing matrices up to symmetry

I am interested in the equivalence relation on N x N binary matrices, in which two matrices are equivalent if one can be obtained by rotating/reflecting the other. I would like to obtain a list ...
4
votes
2answers
165 views

How can I replace the general element of a geometric series with the sum of the series?

Consider the list mylist = {b(a/bc t)^r, a/b(b t)^r, a (c/d t)^r, ...} where a, b, c, t, etc., are real numbers between 0 and 1. I want to sum each term in the ...
19
votes
7answers
975 views

Elegant and fast way to join all string sequences

I want to do what title says: {"a","b",1,2,3,4,"a",2,2,2,"edg","?"} => {"ab",1,2,3,4,"a",2,2,2,"edg?"} in the most elegant way. For example one replacement rule for ...
2
votes
1answer
110 views

Flat function with repeated sequence

There are functions like Join[ ] that accept a variable number of arguments. Join is a flat function, as the order of arguments ...
4
votes
5answers
826 views

Removing zero values from ordered pairs

I have some processed data, which are basically a collection of ordered pairs in the form: {{x1, y1}, {x2, y2}, ..., {xn, yn}} Ordered pairs which have either a ...
8
votes
4answers
401 views

Best way to modify values in a list of rules?

Recently I had to solve a problem similar to this: Let's say I have a list of list of rules ...
9
votes
5answers
293 views

How can I remove matching sublists from my list?

I want to use DeleteCases (or any appropriate function) to remove elements of a list, which in turn are lists of fixed size. The rule I wish to apply is that any ...
1
vote
2answers
261 views

How to generate patterns by a list of integers

I have a list of integers {3,4,2,2}. This list will give patterns {x_,_,y_,y_,_,_,z_,z_,w_,w_,x_} and ...
8
votes
1answer
178 views

Transformation rule on a list of non-negative integers

I am trying to create a transformation rule that takes a list of non-negative integer values of any length, finds a non-zero entry in the list, adds 1 to all preceding numbers, subtracts 1 from the ...
34
votes
6answers
2k views

Find zero crossing in a list

I'm looking for a function that finds the index of the zero-crossing points of a list. Before I go making my own subroutine to do this, I was wondering if anyone knows of any built-in Mathematica ...
6
votes
1answer
376 views

Count sublists which match pattern

I have a list which looks like this: data={{12,0},{0,0},{20,1},{0,0}, {0,-1}}. Now I would like to count the number of sublists which: have both slots zero the ...
13
votes
6answers
2k views

Counting negative values in list

I would like to count the negative values of a list. My approach was Count[data, -_] which doesn't work. How can I tell Mathematica to count all numbers with ...
1
vote
2answers
160 views

Using patterns in ReplaceAll to extract elements from tuples at arbitrary depths

Please consider the following: I need to extract from MyList all last parts of each 3-tuple. ...
12
votes
4answers
297 views

The gap between MapAt and ReplacePart for 2D data tables with headers

Consider a relational table derived from survey data, where each column ("001-01" ...) represents a responder and each row (...
7
votes
3answers
511 views

Specifying string patterns in DeleteCases

It seems that DeleteCases is not compatible with string patterns, at least directly (see, for example, this question). Is this true? If so, why is this the case? ...
5
votes
3answers
443 views

position of sequence of elements in list [duplicate]

Possible Duplicate: Finding a subsequence in a list Question The position of {3, 5} is the list {1, 3, 4, 3, 5, 5, 1} is 3. How can such a position ...
7
votes
1answer
195 views

Built in way to de-list singletons?

Is there a built in method to de-list singleton expressions, like this rule-based solution: expr_ :> If[Length[expr] == 1, First@expr, expr] In data ...
7
votes
2answers
315 views

Building a tree

Given a list of word characters, such as this one, I'd like to build a tree, similar to this makeTree function, but with the tree in a different format. So, for an input such as ...
4
votes
4answers
514 views

Creating lists from a string, separating words from numbers

Say I have a string that contains numbers and words, such as this one: string = "there are 1234 words and numbers 5678 in here $999"; How would I separate the ...
9
votes
4answers
531 views

Using Position (which requires a pattern) in the same manner as Select (which requires a criterion)

I am using Mathematica7. I have a list of lists (creatively named list in the following sample code) containing data. I would like to find the positions of the ...
2
votes
2answers
292 views

Pattern test for variables during function definition

I am having a problem with pattern testing on variables during function definition ...
16
votes
4answers
431 views

Splitting a list

Please consider the following list: data={1, 0, 0, 0, 2, 5, 2, 3, 0, 0, 3}; Now I would like to split the list into 0-sequences and Not-0-sequences as following: ...
11
votes
3answers
507 views

Delete duplicates in a list, depending on the sequence of numbers

Below, list is a representative sample of my list, which contains lists of integers. I would like to be able to input: ...
2
votes
2answers
106 views

Using FreeQ with implicit functions

In Mathematica 7, I want to determine whether a list of free of numbers greater than 1 or not. It seems like using FreeQ would be a concise way to do this: ...
9
votes
3answers
243 views

Splitting a list in which figures vary from negative to positive

Consider the following list: data={4078, 256, -1266, -388, 1290, 1368, 1446, 1524, 2}; I would like to split any kind of such list always, when figures turn form ...
4
votes
1answer
226 views
4
votes
2answers
291 views

Why can't NumberQ be used as the head of a pattern?

Consider the following: list={1/First[{}], 1, 2, 1/First[{}], 3}; DeleteCases[list,_NumberQ] I wanted to remove all cases, which did not match ...
4
votes
1answer
299 views

Path queries for tree-structured data

Can anyone suggest documentation or tutorials for developing path queries and indices for (XML-like) tree-structured data? Suppose data is organized hierarchically in key->value pairs, eg: ...
8
votes
4answers
267 views

Check in a series if there exists adjacent values with less than a certain number of missing values

I'm working with a large number of series of different experiments, where there exist a lot of experiments where there are no entries. I now want to draw a sample where there should exist at least ...