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Questions tagged [parsing]

Questions about built-in/custom parsers or parsing techniques.

3
votes
3answers
64 views

Subsequence Search

I need to parse some xml code. I need to extract some values withing pattern elements. I made an example of my trouble. Here is some complicated xml list: ...
0
votes
0answers
26 views

How do I replace a specific parse expression with a number in a parse calculation?

If t^2 + a^2 + b^2 + c^2 = 1. Is there any way to replace the t^2 + a^2 + b^2 + c^2 expression to the number ...
3
votes
0answers
61 views

Slight loss of precision when parsing JSON

Exporting to JSON is working well for me under 11.3. The issue present in previous versions seem to be solved: ...
11
votes
1answer
138 views

Lexical scanning and parsing in a toy language

I'm trying to do lexical scanning and parsing in a toy language. One with just functions (of the form $f(a,\,b,\,c,\,...)$, ended with semicolons) and special tokens (such as ...
2
votes
0answers
36 views

Confusing behavior for GrammarRules and GrammarApply

I have been experimenting with GrammarRules in an attempt to create a parser for text downloaded from the web. I have been using Interpreter to help understand the behavior of GrammarApply. Here is a ...
11
votes
1answer
97 views

Precedence of cell group tokens over package's expressions

Bug introduced in V10.4 or earlier and persisting through V11.3 [CASE:4072996] ...
9
votes
4answers
1k views

How to convert a string having nested parentheses into an expression?

I am a Wolfram Language/Mathematica beginner and trying to convert STEP ISO10303 commands into geometrical regions. A simple command looks like ...
5
votes
1answer
304 views

How to determine if RHS of first order ODE is separable or linear or neither? Parsing problem

Introduction This is really a parsing question. But the context is that given the right side of first order ode, I want to automatically determine the class of the RHS. It can be either separable, ...
17
votes
1answer
344 views

Is building an event-based parser possible/reasonable in Mathematica (WL)?

Too long? Go to Problems section Background I like to learn by doing small, sometimes artificial, projects. Among other things I had 'parsers', and 'stream methods / streams in MMA' on my to learn ...
7
votes
2answers
233 views

Getting the front sign of an expression. Positive or negative for formatting only

This is for the purpose of generating a string (actually it will Latex string, but that is not important). I need to generate string as ...
5
votes
1answer
52 views

Can we make preread replacements in an *.m* file before being run?

This the second question of (152743), the preamble of which is reproduced here: Those who don't have/prefer the front end of Mathematica will either use a plain ASCII editor to write a script in an ...
5
votes
1answer
47 views

Can we make new definitions for InputForm in packages?

Those who don't have/prefer the front end of Mathematica will either use a plain ASCII editor to write a script in an .m file or just use Mathematica directly from ...
1
vote
0answers
68 views

Scraping XML Paragraphs with URLs

I've been working on scraping an article from CNBC. The link is here I want to scrape the main body, and the code I have so far is this: ...
1
vote
1answer
103 views

Ugly Gaussian symbolic integration, how to extract coefficients and exponent argument?

I have a very ugly function with 157 terms that I want to integrate over three variables. Each term is a Gaussian integral in those variables multiplied by a polynomial in the variables. However, in ...
3
votes
1answer
323 views

Pulling Out Values from JSON Association

Having a bit of trouble pulling a value out of a JSON Association here. I am scraping this website: http://www.msn.com/en-us/money/stockdetails/history/fi-126.1.BY.NYS I want to scrape the closing ...
0
votes
0answers
273 views

HTTP Status Code 403

I'm working with some scraping and have run into a bit of a problem. The website I am scraping is this: https://seekingalpha.com/symbol/CRM/stocktalks I am essentially trying to scrape the "stock ...
1
vote
1answer
51 views

Extracting Certain Areas of JSON

I've been working with some web scraping and have run into a wall. The website I'm working with is this: https://seekingalpha.com/symbol/TWLO/stocktalks I am trying to scrape all of the "stock talks" ...
2
votes
1answer
202 views

Parsing and Extracting XML Content

I've run into a little question while trying to parse XML. This seems like a rather simple task, but for the life of me I cannot figure it out. I pull up the XML of the website using the following ...
2
votes
2answers
288 views

Parse command line arguments

I have been trying to parse command line arguments. There are a couple of types of options. 1. Mandatory 2. Optional 3. Alternative There are built-in/3rd ...
6
votes
0answers
81 views

Infix non-ASCII operator needs a space to be parsed correctly in a script

Bug introduced in 9.0 or earlier and persisting through 11.1 First off: ...
5
votes
1answer
936 views

How to parse JSON

please forgive me if this is obvious, but I have some JSON: ...
3
votes
0answers
32 views

Unexpected behaviour with WordSeparators and Read [duplicate]

I am confused about how Read separates elements. The following all work fine: ...
4
votes
1answer
155 views

Context inside Do[…]-loop

Consider the following code: Begin["mycontext`"]; myvar = 7; Print[Context[]]; Print[Context[myvar]]; End[]; with the output mycontext` mycontext` Now ...
3
votes
2answers
495 views

Reading a text file and parsing only the text between two delimiters

How are you? I'm a chemist with almost no experience with Mathematica, but I'm thinking of using it as a tool for my Ph.D in Computational Chemistry. My Quantum Chemistry software (ORCA) generates a ...
1
vote
2answers
149 views

How is a single tilde parsed?

How is a~b parsed and evaluated? I would expect an error, but it goes through without any complaints, yielding no apparent output. At first I thought it evaluated ...
4
votes
1answer
57 views

How do I import a Dataset that contains lists?

The very first example in the Dataset documentation is the following: ...
3
votes
1answer
85 views

How to use MakeExpression for single characters

Here is code that I thought would make the front end parse f as BigFunction: ...
10
votes
4answers
1k views

How to get the longest bracket pairs from a string

In C#, we can use regular expression to do some balancing groups, like we can get {<aa <bbb> <bbb> aa>, <<dfa>a>} from ...
18
votes
4answers
817 views

Is it important that the front-end has a built-in parser?

The Notebook interface has a parser that seems aware of all operator-precedences, allowing us to step through the expressions (rather: Box-) hierarchy with Ctrl+. This is extremely convenient, saving ...
6
votes
1answer
65 views

Can Read[] apply a custom function automatically to the read values?

Read[stream, Number] will return a single read number. We can use a number of standard, documented types instead of Number, ...
3
votes
0answers
116 views

SymbolicC/SymbolicCUDAFunction generating C/C++ parser?

I wish to do some program transformation and analysis. Is there any package that generates SymbolicC expressions from C code? In a sense I'm looking for the ...
3
votes
1answer
82 views

How to speed up accidental large output?

From time to time I accidentally let large expressions like RandomReal[1., {10^5, 10, 10}] reach the front end. The computation of the result is quite fast (...
9
votes
1answer
206 views

Why is this syntax for patterns with Optional values not supported?

I want to express Optional[PatternTest[Pattern[a,Blank[]],t],1] concisely. a : _?t : 1 is not quite this but works: ...
4
votes
0answers
79 views

Weird bug with Esc, string, and underscore? [closed]

There seems to be a bug with esc key, strings, and underscores. For instance, see the following code: a = f["1_2"]; If an esc character is typed anywhere ...
1
vote
2answers
89 views

Use cases to exclude data values over a certain threshold

I am trying to parse data output from a fluorometer. My output is basically signal intensity over time. So I have a list of 2 value lists with the first value time and the second signal e.g., ...
8
votes
2answers
237 views

FullForm with context for each symbol?

FullForm strips the context for any symbol that can be found on the Append[$ContextPath, $Context]: ...
0
votes
1answer
166 views

How to read a part of huge matrix saved in a TXT file as single expression?

I saved a huge matrix of numbers with dimensions {400, 4001, 2} using Put and got a TXT file formatted in the following way: <...
5
votes
1answer
199 views

How to get “one Cell - one line” code format inside of NB files?

The PageWidth option controls the way the Cell's content is displayed, not the manner it's written in a ...
21
votes
2answers
579 views

Shell Emulation inside Mathematica

I am trying to create a Mathematica/shell syntax hybrid. I would like the following command wget -qO- "http://google.com/space line break\"" $var to be ...
4
votes
1answer
229 views

When does Mathematica insert parenthesis into expression?

expr//HoldForm usually returns identical expressions as input, but sometimes parenthesis are inserted. I tried to interpret this behavior as an attempt to eliminate ...
14
votes
2answers
905 views

How to parse a clojure expression?

Clojure is a lisp-like language that runs on JVM and in Javascript. I just started learning it and I'm building a simple parser with Mathematica to understand and visualize it. Like other lisps every ...
3
votes
1answer
82 views

Skipping commented in a stream from OpenRead

Is there a solution to skip comments in text files that are imported with OpenRead? I know there are solutions for Importand <...
3
votes
1answer
89 views

`ReadString` and `StreamPosition` behaving strangely with custom terminators

I've stumbled on a strange behavior while trying to use custom terminators for ReadString. When I use a simple String as the ...
4
votes
3answers
1k views

Importing CSV with multiline text fields

Bug introduced in 8 or earlier and fixed in 11.2.0 Here is a valid CSV: a1,b1,c1,d1,"e1 e1 e1" a2,b2,"c2 c2 c2",d2,e2 It has two rows and five columns, and ...
4
votes
1answer
253 views

How to get the list of links in a Wikipedia article in order of appearance

I can get a list of links in a Wikipedia article using WikipediaData: ...
2
votes
0answers
83 views

Where do the radicals end?

In an early iteration of this question on the Mathematics SE, the radicals weren't properly formatted, so they only had the √ symbol with no indication of which terms were supposed to be ...
4
votes
2answers
202 views

Parsing tab delimited file

Problem Description I have my data arranged in a tab delimited file and I'm trying to parse/access certain parts of it. As an example, I'd like to extract the number of points and the sampling ...
0
votes
0answers
560 views

How to prevent space trimming when importing HTML with ImportString?

I am importing a HTML-formatted string with ImportString[string, "HTML"] to properly parse all HTML-escaped characters like ...
32
votes
0answers
533 views

Front end goes wild with named slots

Bug introduced in 10 and persisting through 12.0.0 Assume the following simple expression {#"Test"}& Now go in front of the ...
16
votes
0answers
211 views

Why does the FrontEnd lose matching of parentheses when we insert quotations?

Bug introduced in V10.0 and resolved in V11.3 (These are guesses. It is likely to have been resolved in an earlier version V11.X, but V11.3 is what I have access to.) I am running Mathematica 10.0....