Questions on the manipulation of String objects in Mathematica, and the functions used for these manipulations.

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33
votes
3answers
1k views

Visualizing the difference between two sequences (strings)

I'm trying to develop a way of comparing two sequences (probably originally text, such as text writing or source code, possibly converted to lists). As a familiar example, consider the revisions ...
26
votes
0answers
356 views

Why is StringExpression faster than RegularExpression?

Edit: as noted by Albert Retey the performance difference is only seen when sub expression extraction is performed. If this test is used below the timings are similar: ...
23
votes
4answers
3k views

Looking for “Longest Common Substring” solution

I'm looking for robust code to solve the "Longest Common Substring" problem. I can just code it up from that description, but I'd thought I'd ask here, first, in case someone knows of an ...
23
votes
5answers
3k views

How do you convert a string containing a number in C scientific notation to a Mathematica number?

Suppose I have a string containing the C-representation of a floating point number, for example s = "1.23e-5" and I want to convert this to a Mathematica number. ...
23
votes
4answers
1k views

What is the fastest way to count square-free words?

Background A word is a string of letters in an alphabet. A square-free word has no adjacent repeating substring. For example, (in the ternary alphabet of {0,1,2}) the words 00, 012121, and 0212012021 ...
23
votes
1answer
539 views

Convenient string manipulation

With Mathematica I always feel that strings are "second class citizens." Compared to a language such as PERL one must juggle a lot of code to accomplish the same task. The available functionality is ...
22
votes
9answers
3k views

Programming paradigm change

I'm new to Mathematica, I've been learning by myself, and, being a Java developer for some time, it makes it hard to adapt. I've tried to solve a Reddit challenge, and I came up with this solution: ...
22
votes
7answers
956 views

Splitting words into specific fragments

I am looking into splitting words into a succession of chemical elements symbols, where possible. For example: Titanic = Ti Ta Ni C (titanium, tantalum, nickel, carbon) A word may or may not be ...
21
votes
3answers
913 views

How to join two Style[]d strings

Does anyone know whether it is possible to combine\join two styled strings? That is, while the following code works fine: omega = "text"; omega<>omega ...
21
votes
6answers
522 views

Partition string into chunks

This seems like it should be trivial, but how do I partition a string into length n substrings? I can of course write something like ...
18
votes
7answers
909 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 ...
17
votes
2answers
1k views

How to import all files of a folder at once?

I know how to import one textfile by calling its name filestring = Import["myfile.tex", "Text"]; Then "filestring" is a string with the myfile content. How do ...
17
votes
3answers
328 views

Unexpected result {“.a”, “co”, “.m”} from Sort[{“.m”, “.a”, “co”}]

I came across the following situation: Evaluating Sort[{".m", ".a", "co"}] Results in {".a", "co", ".m"} I wondering: ...
16
votes
6answers
652 views

Split a string at specific positions

Given a string of alphanumerical characters, how to split it simply and quickly at the center of continuous letter-substrings? Is there an elegant and fast solutions out there in the "computational ...
16
votes
2answers
691 views

How do I perform string matching and replacements?

What are, and how do I use Mathematica's string matching and replacement tools?
16
votes
1answer
408 views

NotebookFind and String Pattern Expressions

Is there a way that NotebookFind can be used to match string pattern expressions rather than just strings? The documentation for ...
15
votes
7answers
1k views

How to express an integer number in English words?

How do I convert a number to a readable string? I would like to implement a function, inWords[], inWords[n_]:= ? which ...
15
votes
1answer
223 views

How to strip all formatting from a string and convert it to plain text?

The documentation on String states: But if I try to perform some manipulations on this string, for example, take 2 words from the left, I get some shards of ...
15
votes
4answers
689 views

Finding all dictionary words that can be made with a given set of characters (Wordfeud/Scrabble)

This is a slightly more involved variant of this recent question. By sheer coincidence I happened to have been building a Wordfeud (Scrabble clone) game in Mathematica. My interactive Wordfeud ...
14
votes
5answers
1k views

sprintf() or close equivalent, or re-implementation?

Is there a sprintf() command (some command that takes a printf-style format string and a list of values to insert into the ...
14
votes
4answers
724 views

Converting a large floating-point number to a single-line string

When I feed a large (or small) enough floating-point number to ToString, it produces a two-line string, with the first line containing only the exponent of 10: ...
14
votes
6answers
437 views

Splitting a list by specifying section headers

I have a list of strings called mylist: mylist = {"[a]", "a", "a", "[b]", "b", "b", "[ c ]", "c", "c"}; I would like to split ...
14
votes
3answers
435 views

Grabbing a number of characters around a string pattern

If I have some string data: text = StringTake[ExampleData[{"Text", "DeclarationOfIndependence"}], 400] "When in the Course of human events, it becomes ...
14
votes
2answers
358 views

Unicode-aware string functions?

I've recently discovered that ToUpperCase is quite unreliable on non-ASCII input: ...
14
votes
2answers
463 views

Lexicographic ordering of strings in Mathematica

I recently realized that Mathematica seems incapable of comparing strings in the "normal" expected lexicographic order. Indeed, for some simulations, I need to process text directly, without fiddling ...
14
votes
2answers
267 views

Haiku Extractor

Inspired by the cool Tumblr Haiku Times that searches for accidental haiku in New York Times articles, I tried my hand at implementing such a search in Mathematica for my own text samples. I'm still ...
13
votes
2answers
346 views

How to embed an image into a string?

The documentation for String contains the following statements: Strings can contain any sequence of ordinary and special characters: … Strings preserve ...
12
votes
7answers
560 views

DeleteCases on list of Strings

Consider the following: data={"AB","CD","AF"}; Now I would like to delete all String from data which starts with "A". ...
12
votes
4answers
462 views

How do you get a list of filenames from a URL?

How would I get a list of filenames available at a URL? For example, list the files at: http://www1.ncdc.noaa.gov/pub/data/cmb/drought/weekly-palmers/2005/
12
votes
5answers
466 views

How to remove duplicate characters from a string?

How do you remove duplicate characters in a string without converting the string to a list. I want to delete all duplicate characters in a string (i.e. get the unsorted union of characters). For ...
12
votes
2answers
302 views

Split a Unicode string maintaining uppercase characters

I want to split a string according to a predefined set of substrings (lowercase), though the actual text can contain uppercase characters anyplace. The task is to find the matches, longer preferred ...
11
votes
5answers
1k views

What is the fastest way to extract a substring from a huge string?

I develop an algorithm to find the most common substrings of a given length n up to a certain distance l in front of a pattern p in a huge sequence S. E.g. I want to find the most common hexamers ...
11
votes
2answers
213 views

Pasting “rectangles” of text side-by-side

In Emacs/Xemacs, there is a rectangle feature, such that you can delete, copy, etc., "rectangles" of text. Now suppose I have two text files, each containing one column of numbers. Is it possible to ...
11
votes
1answer
456 views

Rearranging a Polynomial

In Mathematica 8.04 on Windows, I want to display a formula in standard textbook format. The formula is the variance of an $N$-security portfolio. For two securities it is: ...
11
votes
2answers
253 views

Should I use \\\“ or \” to match " in regex?

Both of the following return True: ...
11
votes
2answers
262 views

Transform fancy usage messages in 1D string

When we look at the usage messages of built-in functions nowadays (not in the good old times, when they were a simple descriptions) we see that although they look pretty in the front end, it is really ...
10
votes
9answers
2k views

How do I extract a number from a string?

I want to extract the number from an alphanumeric string. This is what I tried: StringTake["thiru3", {6, 6}] The result I got is ...
10
votes
7answers
200 views

DateList coupled with String Operations

Through some webscraping, I have the following list: ...
10
votes
2answers
213 views

What's a robust way to insert another extension into a filename?

I'd like to add an extension to a filename before the file extension, otherwise leaving the given filename the same. In particular, absolute filenames should stay absolute, and relative filenames ...
10
votes
2answers
289 views

Mathematica Typing Effect

Here is a Typing Effect in javascript. I could only implement a very simple one: ...
10
votes
1answer
399 views

Mathematica equivalent of regex '\w{2,3}'

It beats me to write the Mathematica pattern equivalent to the regex: \w{2,3} Any ideas?
10
votes
2answers
468 views

How to get string representation (like repr in Python)

I have a string variable. I want to obtain another string which contains the representation of the string variable content itself. s = "a \n b" I need to get a ...
9
votes
5answers
592 views

convert long string to integer list

at first, i would like to thank all the people here. i'm working with mathematica for half a year now and always found great advice and tricks. now, i came up with a problem i couldn't find a ...
9
votes
3answers
369 views

How to remove accents from text?

I would like to know how I can remove accents from a string. For example, how can I transform "string test áéíóú" into ...
9
votes
2answers
213 views

Behavior of ImportString in Mathematica

I tried the following commands ...
9
votes
4answers
351 views

How does string interpolation work in Mathematica

I've noticed that Mathematica 8 seems to have some kind of string interpolation feature, but I couldn't find any documentation on it and I can't figure out how it works. For example, if I enter ...
9
votes
3answers
228 views

balanced Shortest[] and string-patterns

The pattern Shortest["A"~~__~~"B"] is oriented : It assumes the text is read from left to right and it takes the text between the first "A" and the next "B". Any ...
9
votes
1answer
118 views

Named string patterns in Alternatives, why does it depend on order?

When using the same name for part of patterns inside Alternatives how come it behaves differently for strings than in normal patterns? ...
8
votes
2answers
1k views

Convert a string to hex number?

How can I convert a string containing a hex number such as "6b" to a hex digit that mathematica can use to do math with? I have tried using ...
8
votes
2answers
256 views

Keeping Quotation Marks in Output

I am running into the following seemingly simple problem. I have this code: testphrase="i love you"; input=ToLowerCase[StringSplit[testphrase, Whitespace]] It ...