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  • What are block expressions actually good for?

    - by Helper Method
    I just solved the first problem from Project Euler in JavaFX for the fun of it and wondered what block expressions are actually good for? Why are they superior to functions? Is it the because of the narrowed scope? Less to write? Performance? Here's the Euler example. I used a block here but I don't know if it actually makes sense // sums up all number from low to high exclusive which are divisible by a or b function sumDivisibleBy(a: Integer, b: Integer, high: Integer) { def low = if (a <= b) a else b; def sum = { var result = 0; for (i in [low .. <high] where i mod 3 == 0 or i mod 5 == 0) { result += i } result } } Does a block makes sense here?

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  • Dealing with regular expressions, Python

    - by Gusto
    I want to remove some symbols from a string using a regular expression, for example: == (that occur both at the beginning and at the end of a line), * (at the beginning of a line ONLY). def some_func(): clean = re.sub(r'= {2,}', '', clean) #Removes 2 or more occurrences of = at the beg and at the end of a line. clean = re.sub(r'^\* {1,}', '', clean) #Removes 1 or more occurrences of * at the beginning of a line. What's wrong with my code? It seems like expressions are wrong. How do I remove a character/symbol if it's at the beginning or at the end of the line (with one or more occurrences)?

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  • Regular expressions in python unicode

    - by Remy
    I need to remove all the html tags from a given webpage data. I tried this using regular expressions: import urllib2 import re page = urllib2.urlopen("http://www.frugalrules.com") from bs4 import BeautifulSoup, NavigableString, Comment soup = BeautifulSoup(page) link = soup.find('link', type='application/rss+xml') print link['href'] rss = urllib2.urlopen(link['href']).read() souprss = BeautifulSoup(rss) description_tag = souprss.find_all('description') content_tag = souprss.find_all('content:encoded') print re.sub('<[^>]*>', '', content_tag) But the syntax of the re.sub is: re.sub(pattern, repl, string, count=0) So, I modified the code as (instead of the print statement above): for row in content_tag: print re.sub(ur"<[^>]*>",'',row,re.UNICODE But it gives the following error: Traceback (most recent call last): File "C:\beautifulsoup4-4.3.2\collocation.py", line 20, in <module> print re.sub(ur"<[^>]*>",'',row,re.UNICODE) File "C:\Python27\lib\re.py", line 151, in sub return _compile(pattern, flags).sub(repl, string, count) TypeError: expected string or buffer What am I doing wrong?

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  • Mutually exclusive regular expressions

    - by CaptnCraig
    If I have a list of regular expressions, is there an easy way to determine that no two of them will both return a match for the same string? That is, the list is valid if and only if for all strings a maximum of one item in the list will match the entire string. It seems like this will be very hard (maybe impossible?) to prove definitively, but I can't seem to find any work on the subject. The reason I ask is that I am working on a tokenizer that accepts regexes, and I would like to ensure only one token at a time can match the head of the input.

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  • .NET Regular Expressions - Shorter match

    - by Xavier
    Hi Guys, I have a question regarding .NET regular expressions and how it defines matches. I am writing: var regex = new Regex("<tr><td>1</td><td>(.+)</td><td>(.+)</td>"); if (regex.IsMatch(str)) { var groups = regex.Match(str).Groups; var matches = new List<string>(); for (int i = 1; i < groups.Count; i++) matches.Add(groups[i].Value); return matches; } What I want is get the content of the two following tags. Instead it returns: [0]: Cell 1</td><td>Cell 2</td>... [1]: Last row of the table Why is the first match taking </td> and the rest of the string instead of stopping at </td>?

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  • Saving substrings using Regular Expressions

    - by user362971
    I'm new to regular expressions in Java (or any language, for that matter) and I'm wanting to do a find using them. The tricky part that I don't understand how to do is replace something inside the string that matches. For example, if the line I'm looking for is Person item6 [can {item thing [wrap]}] I'm able to write a regex that finds that line, but finding what the word "thing" is (as it may differ among different lines) is my problem. I may want to either replace that word with something else or save it in a variable for later. Is there any easy way to do this using Java's regex engine?

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  • javascript regular expressions

    - by Zhasulan Berdybekov
    Help me with regular expressions. I need to check the text on the hour and minute. That is the first case, the text can be from 0 to 12. In the second case, the text can be from 1 to 60. this is my code: var hourRegEx = /^([0-9]{2})$/; //You can fix this line of code? $(document).ready( function(){ $('form.form').submit(function(){ if( $('input.hour').val().match(hourRegEx) ){ return true; } return false; }); }); In my case, the code says that, for example 52, too, the correct answer

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  • offsetWidth or CSS expression problem for IE6

    - by Bipul
    I need to set the width of textboxes as 80% of it's parent. So first I used td input[type="text"] { width: 80%; } But it was not rendering properly if the input is the child of td. So, I used Css expressions td input[type="text"] { width: expression(this.parentNode.offsetWidth*0.8); } It is working as I wanted in every browser except IE 6. Can anybody help me, where I am going wrong? I know that expressions are allowed in IE 6. So, is it the problem of using css expression or something to do offsetWidth. Thanks in advance.

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  • What RegEx should I use to return parameter names wrapped within brackets in an expression?

    - by burak ozdogan
    Hi, I have a set of expressions representing some formula with some parameters inside. Like: "[parameter1] * [parameter2] * [multiplier]" and many others like this. I want to use a regEx so that I can get a list of strings (List<string> ) which will have [paramter1] [paramter2] [multiplier] inside. I am not using regular expressions so often; if you have already used something like this I would appreciate if you can share. Thanks!

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  • Are there any formalized/mathematical theories of software testing?

    - by Erik Allik
    Googling "software testing theory" only seems to give theories in the soft sense of the word; I have not been able to find anything that would classify as a theory in the mathematical, information theoretical or some other scientific field's sense. What I'm looking for is something that formalizes what testing is, the notions used, what a test case is, the feasibility of testing something, the practicality of testing something, the extent to which something should be tested, formal definition/explanation of code coverage, etc. UPDATE: Also, I'm not sure, intuitively, about the connection between formal verification and what I asked, but there's clearly some sort of connection.

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  • Why can't flowcharts or mathematical equations created in Microsoft Office and saved in .docx format be opened by LibreOffice?

    - by user33831
    I am using Ubuntu 11.10 and LibreOffice that comes with it. Before this , I was a Windows user and some of my previous documents were saved in .docx format. I tried to use LibreOffice to open those .docx file and I can view all text, however I can't view the flowchart I drew and also mathematical equations. Another issue is, if I create new flowchart with LibreOffice and save it in .docx file, when I re-open that file, I can't view those flowcharts, but those flowcharts are there, occupied space. No problem for .odt format of course. Does anyone know why this happens? Thanks in advanced.

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  • Mathematica regular expressions on unicode strings.

    - by dreeves
    This was a fascinating debugging experience. Can you spot the difference between the following two lines? StringReplace["–", RegularExpression@"[\\s\\S]" -> "abc"] StringReplace["-", RegularExpression@"[\\s\\S]" -> "abc"] They do very different things when you evaluate them. It turns out it's because the string being replaced in the first line consists of a unicode en dash, as opposed to a plain old ascii dash in the second line. In the case of the unicode string, the regular expression doesn't match. I meant the regex "[\s\S]" to mean "match any character (including newline)" but Mathematica apparently treats it as "match any ascii character". How can I fix the regular expression so the first line above evaluates the same as the second? Alternatively, is there an asciify filter I can apply to the strings first? PS: The Mathematica documentation says that its string pattern matching is built on top of the Perl-Compatible Regular Expressions library (http://pcre.org) so the problem I'm having may not be specific to Mathematica.

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  • Parsing Lisp S-Expressions with known schema in C#

    - by Drew Noakes
    I'm working with a service that provides data as a Lisp-like S-Expression string. This data is arriving thick and fast, and I want to churn through it as quickly as possible, ideally directly on the byte stream (it's only single-byte characters) without any backtracking. These strings can be quite lengthy and I don't want the GC churn of allocating a string for the whole message. My current implementation uses CoCo/R with a grammar, but it has a few problems. Due to the backtracking, it assigns the whole stream to a string. It's also a bit fiddly for users of my code to change if they have to. I'd rather have a pure C# solution. CoCo/R also does not allow for the reuse of parser/scanner objects, so I have to recreate them for each message. Conceptually the data stream can be thought of as a sequence of S-Expressions: (item 1 apple)(item 2 banana)(item 3 chainsaw) Parsing this sequence would create three objects. The type of each object can be determined by the first value in the list, in the above case "item". The schema/grammar of the incoming stream is well known. Before I start coding I'd like to know if there are libraries out there that do this already. I'm sure I'm not the first person to have this problem.

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  • Combine regular expressions for splitting camelCase string into words

    - by stou
    I managed to implement a function that converts camel case to words, by using the solution suggested by @ridgerunner in this question: Split camelCase word into words with php preg_match (Regular Expression) However, I want to also handle embedded abreviations like this: 'hasABREVIATIONEmbedded' translates to 'Has ABREVIATION Embedded' I came up with this solution: <?php function camelCaseToWords($camelCaseStr) { // Convert: "TestASAPTestMore" to "TestASAP TestMore" $abreviationsPattern = '/' . // Match position between UPPERCASE "words" '(?<=[A-Z])' . // Position is after group of uppercase, '(?=[A-Z][a-z])' . // and before group of lowercase letters, except the last upper case letter in the group. '/x'; $arr = preg_split($abreviationsPattern, $camelCaseStr); $str = implode(' ', $arr); // Convert "TestASAP TestMore" to "Test ASAP Test More" $camelCasePattern = '/' . // Match position between camelCase "words". '(?<=[a-z])' . // Position is after a lowercase, '(?=[A-Z])' . // and before an uppercase letter. '/x'; $arr = preg_split($camelCasePattern, $str); $str = implode(' ', $arr); $str = ucfirst(trim($str)); return $str; } $inputs = array( 'oneTwoThreeFour', 'StartsWithCap', 'hasConsecutiveCAPS', 'ALLCAPS', 'ALL_CAPS_AND_UNDERSCORES', 'hasABREVIATIONEmbedded', ); echo "INPUT"; foreach($inputs as $val) { echo "'" . $val . "' translates to '" . camelCaseToWords($val). "'\n"; } The output is: INPUT'oneTwoThreeFour' translates to 'One Two Three Four' 'StartsWithCap' translates to 'Starts With Cap' 'hasConsecutiveCAPS' translates to 'Has Consecutive CAPS' 'ALLCAPS' translates to 'ALLCAPS' 'ALL_CAPS_AND_UNDERSCORES' translates to 'ALL_CAPS_AND_UNDERSCORES' 'hasABREVIATIONEmbedded' translates to 'Has ABREVIATION Embedded' It works as intended. My question is: Can I combine the 2 regular expressions $abreviationsPattern and camelCasePattern so i can avoid running the preg_split() function twice?

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  • SQL with Regular Expressions vs Indexes with Logical Merging Functions

    - by geeko
    Hello Lads, I am trying to develop a complex textual search engine. I have thousands of textual pages from many books. I need to search pages that contain specified complex logical criterias. These criterias can contain virtually any compination of the following: A: Full words. B: Word roots (semilar to stems; i.e. all words with certain key letters). C: Word templates (in some languages are filled in certain templates to form various part of speech such as adjactives, past/present verbs...). D: Logical connectives: AND/OR/XOR/NOT/IF/IFF and parentheses to state priorities. Now, would it be faster to have the pages' full text in database (not indexed) and search though them all using SQL and Regular Expressions ? Or would it be better to construct indexes of word/root/template-page-location tuples. Hence, we can boost searching for individual words/roots/templates. However, it gets tricky as we interdouce logical connectives into our query. I thought of doing the following steps in such cases: 1: Seperately search for each individual words/roots/templates in the specified query. 2: On priority bases, we merge two result lists (from step 1) at a time depedning on the logical connective For example, if we are searching for "he AND (is OR was)": 1: We shall search for "he", "is" and "was" seperately and get result lists for each word. 2: Merge the result lists of "is" and "was" using the merging function OR-MERGE 3: Merge the merged result list from the OR-MERGE function with the one of "he" using the merging function AND-MERGE The result of step 3 is then returned as the result of the specified query. What do you think gurues ? Which is faster ? Any better ideas ? Thank you all in advance.

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  • Algorithm(s) for rearranging simple symbolic algebraic expressions

    - by Gabe Johnson
    Hi, I would like to know if there is a straightforward algorithm for rearranging simple symbolic algebraic expressions. Ideally I would like to be able to rewrite any such expression with one variable alone on the left hand side. For example, given the input: m = (x + y) / 2 ... I would like to be able to ask about x in terms of m and y, or y in terms of x and m, and get these: x = 2*m - y y = 2*m - x Of course we've all done this algorithm on paper for years. But I was wondering if there was a name for it. It seems simple enough but if somebody has already cataloged the various "gotchas" it would make life easier. For my purposes I won't need it to handle quadratics. (And yes, CAS systems do this, and yes I know I could just use them as a library. I would like to avoid such a dependency in my application. I really would just like to know if there are named algorithms for approaching this problem.)

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  • I need to remove Java Script tags using regular expressions and JRegex

    - by piotr
    I need to remove all the Java Script tags and the content in between and style tags from the HTML code of web pages.So far I've come up with this expression : "(<[ \r\n\t]script([ \r\n\t]|){1,}([ \r\n\t]|.)?)|(<[ \r\n\t]noscript([ \r\n\t]|){1,}([ \r\n\t]|.)?)|(<[ \r\n\t]style([ \r\n\t]|){1,}([ \r\n\t]|.)?)" I use JRegex library to work with regular expressions. When I test it in any regex tester it works just fine, but once I run my program - it all crashes down with this error report: Exception in thread "Thread-0" java.lang.StackOverflowError at java.util.regex.Pattern$BranchConn.match(Unknown Source) at java.util.regex.Pattern$BmpCharProperty.match(Unknown Source) at java.util.regex.Pattern$Branch.match(Unknown Source) at java.util.regex.Pattern$GroupHead.match(Unknown Source) at java.util.regex.Pattern$LazyLoop.match(Unknown Source) at java.util.regex.Pattern$GroupTail.match(Unknown Source) at java.util.regex.Pattern$BranchConn.match(Unknown Source) at java.util.regex.Pattern$CharProperty.match(Unknown Source) at java.util.regex.Pattern$Branch.match(Unknown Source) at java.util.regex.Pattern$GroupHead.match(Unknown Source) at java.util.regex.Pattern$LazyLoop.match(Unknown Source) .................................. And it keeps on going forever. If anyone can give me an advice on this one - I'll be very grateful.

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  • Python Regular Expressions: Capture lookahead value (capturing text without consuming it)

    - by Lattyware
    I wish to use regular expressions to split words into groups of (vowels, not_vowels, more_vowels), using a marker to ensure every word begins and ends with a vowel. import re MARKER = "~" VOWELS = {"a", "e", "i", "o", "u", MARKER} word = "dog" if word[0] not in VOWELS: word = MARKER+word if word[-1] not in VOWELS: word += MARKER re.findall("([%]+)([^%]+)([%]+)".replace("%", "".join(VOWELS)), word) In this example we get: [('~', 'd', 'o')] The issue is that I wish the matches to overlap - the last set of vowels should become the first set of the next match. This appears possible with lookaheads, if we replace the regex as follows: re.findall("([%]+)([^%]+)(?=[%]+)".replace("%", "".join(VOWELS)), word) We get: [('~', 'd'), ('o', 'g')] Which means we are matching what I want. However, it now doesn't return the last set of vowels. The output I want is: [('~', 'd', 'o'), ('o', 'g', '~')] I feel this should be possible (if the regex can check for the second set of vowels, I see no reason it can't return them), but I can't find any way of doing it beyond the brute force method, looping through the results after I have them and appending the first character of the next match to the last match, and the last character of the string to the last match. Is there a better way in which I can do this? The two things that would work would be capturing the lookahead value, or not consuming the text on a match, while capturing the value - I can't find any way of doing either.

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  • Nullability (Regular Expressions)

    - by danportin
    In Brzozowski's "Derivatives of Regular Expressions" and elsewhere, the function d(R) returning ? if a R is nullable, and Ø otherwise, includes clauses such as the following: d(R1 + R2) = d(R1) + d(R2) d(R1 · R2) = d(R1) ? d(R2) Clearly, if both R1 and R2 are nullable then (R1 · R2) is nullable, and if either R1 or R2 is nullable then (R1 + R2) is nullable. It is unclear to me what the above clauses are supposed to mean, however. My first thought, mapping (+), (·), or the Boolean operations to regular sets is nonsensical, since in the base case, d(a) = Ø (for all a ? S) d(?) = ? d(Ø) = Ø and ? is not a set (nor is the return type of d, which is a regular expression). Furthermore, this mapping isn't indicated, and there is a separate notation for it. I understand nullability, but I'm lost on the definition of the sum, product, and Boolean operations in the definition of d: how are ? or Ø returned from d(R1) ? d(R2), for instance, in the definition off d(R1 · R2)?

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  • Evaluating expressions using Visual Studio 2005 SDK rather than automation's Debugger::GetExpression

    - by brone
    I'm looking into writing an addin (or package, if necessary) for Visual Studio 2005 that needs watch window type functionality -- evaluation of expressions and examination of the types. The automation facilities provide Debugger::GetExpression, which is useful enough, but the information provided is a bit crude. From looking through the docs, it sounds like an IDebugExpressionContext2 would be more useful. With one of these it looks as if I can get more information from an expression -- detailed information about the type and any members and so on and so forth, without having everything come through as strings. I can't find any way of actually getting a IDebugExpressionContext2, though! IDebugProgramProvider2 sort of looks relevant, in that I could start with IDebugProgramProvider2::GetProviderProcessData and then slowly drill down until reaching something that can supply my expression context -- but I'll need to supply a port to this, and it's not clear how to retrieve the port corresponding to the current debug session. (Even if I tried every port, it's not obvious how to tell which port is the right one...) I'm becoming suspicious that this simply isn't a supported use case, but with any luck I've simply missed something crashingly obvious. Can anybody help?

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  • Mocking objects with complex Lambda Expressions as parameters

    - by iCe
    Hi there, I´m encountering this problem trying to mock some objects that receive complex lambda expressions in my projects. Mostly with with proxy objects that receive this type of delegate: Func<Tobj, Fun<TParam1, TParam2, TResult>> I have tried to use Moq as well as RhinoMocks to acomplish mocking those types of objects, however both fail. (Moq fails with NotSupportedException, and in RhinoMocks simpy does not satisgy expectation). This is simplified example of what I´m trying to do: I have a Calculator object that does calculations: public class Calculator { public Calculator() { } public int Add(int x, int y) { var result = x + y; return result; } public int Substract(int x, int y) { var result = x - y; return result; } } I need to validate parameters on every method in the Calculator class, so to keep with the Single Responsability principle, I create a validator class. I wire everything up using a Proxy class, that prevents having duplicate code: public class CalculatorProxy : CalculatorExample.ICalculatorProxy { private ILimitsValidator _validator; public CalculatorProxy(Calculator _calc, ILimitsValidator _validator) { this.Calculator = _calc; this._validator = _validator; } public int Operation(Func&lt;Calculator, Func&lt;int, int, int&gt;&gt; operation, int x, int y) { _validator.ValidateArgs(x, y); var calcMethod = operation(this.Calculator); var result = calcMethod(x, y); _validator.ValidateResult(result); return result; } public Calculator Calculator { get; private set; } } Now, I´m testing a component that does use the CalculatorProxy, so I want to mock it, for example using Rhino Mocks: [TestMethod] public void ParserWorksWithCalcultaroProxy() { var calculatorProxyMock = MockRepository.GenerateMock&lt;ICalculatorProxy&gt;(); calculatorProxyMock.Expect(x =&gt; x.Calculator).Return(_calculator); calculatorProxyMock.Expect(x =&gt; x.Operation(c =&gt; c.Add, 2, 2)).Return(4); var mathParser = new MathParser(calculatorProxyMock); mathParser.ProcessExpression("2 + 2"); calculatorProxyMock.VerifyAllExpectations(); } However I cannot get it to work! Any ideas about how this can be done? Thanks a lot!

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  • List<object>.RemoveAll - How to create an appropriate Predicate

    - by CJM
    This is a bit of noob question - I'm still fairly new to C# and generics and completely new to predicates, delegates and lamda expressions... I have a class 'Enquiries' which contains a generic list of another class called 'Vehicles'. I'm building up the code to add/edit/delete Vehicles from the parent Enquiry. And at the moment, I'm specifically looking at deletions. From what I've read so far, it appears that I can use Vehicles.RemoveAll() to delete an item with a particular VehicleID or all items with a particular EnquiryID. My problem is understanding how to feed .RemoveAll the right predicate - the examples I have seen are too simplistic (or perhaps I am too simplistic given my lack of knowledge of predicates, delegates and lambda expressions). So if I had a List<Of Vehicle> Vehicles where each Vehicle had an EnquiryID, how would I use Vehicles.RemoveAll() to remove all vehicles for a given EnquiryID? I understand there are several approaches to this so I'd be keen to hear the differences between approaches - as much as I need to get something working, this is also a learning exercise. As an supplementary question, is a Generic list the best repository for these objects? My first inclination was towards a Collection, but it appears I am out of date. Certainly Generics seem to be preferred, but I'm curious as to other alternatives. Thanks

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  • How to properly translate the "var" result of a lambda expression to a concrete type?

    - by CrimsonX
    So I'm trying to learn more about lambda expressions. I read this question on stackoverflow, concurred with the chosen answer, and have attempted to implement the algorithm using a console app in C# using a simple LINQ expression. My question is: how do I translate the "var result" of the lambda expression into a usable object that I can then print the result? I would also appreciate an in-depth explanation of what is happening when I declare the outer => outer.Value.Frequency (I've read numerous explanations of lambda expressions but additional clarification would help) C# //Input : {5, 13, 6, 5, 13, 7, 8, 6, 5} //Output : {5, 5, 5, 13, 13, 6, 6, 7, 8} //The question is to arrange the numbers in the array in decreasing order of their frequency, preserving the order of their occurrence. //If there is a tie, like in this example between 13 and 6, then the number occurring first in the input array would come first in the output array. List<int> input = new List<int>(); input.Add(5); input.Add(13); input.Add(6); input.Add(5); input.Add(13); input.Add(7); input.Add(8); input.Add(6); input.Add(5); Dictionary<int, FrequencyAndValue> dictionary = new Dictionary<int, FrequencyAndValue>(); foreach (int number in input) { if (!dictionary.ContainsKey(number)) { dictionary.Add(number, new FrequencyAndValue(1, number) ); } else { dictionary[number].Frequency++; } } var result = dictionary.OrderByDescending(outer => outer.Value.Frequency); // How to translate the result into something I can print??

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  • After Effect - Triangle Wave (JavaScript)

    - by PJ Palomaki
    Hi, I'm trying to control a parameter with AE expressions and I need a triangle wave. I've got this so far: freq = 20; amplitude = 8; m = amplitude; i = time*freq; m - (i % (2*m) - m); Unfortunately this gives a saw wave (see below) and my math's a bit rusty, any takers? Thanks! PJ http://i25.photobucket.com/albums/c73/pjburnhill/Screenshot2010-04-09at153815.png

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