# Questions tagged [semantic-matching]

Posts about semantic pattern matching rather than syntactic pattern matching (which is the built-in pattern matcher of Mathematica) e.g. "Why x^3 /. x^2->a doesn't work!"

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### ReplaceAll with Powers

If I run the following code: a^2/b^2 /. {a/b -> c} I'm getting output: a^2/b^2 How can I obtain ...
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151 views

### What is Wolfram's equivalent of Maple's algsubs?

Maple has two primary substitution functions. subs - which is similar to ReplaceAll in WL. algsubs - which does replacement but takes into account the algebraic ...
• 8,105
225 views

### How do you get substitution to recognize a derivative?

I have a simple expression involving a derivative: x[t_] = Q/T[t]; Simplify[Derivative[1][x][t] /. Q -> x T[t]] That produces:$$-\frac{x T'[t]}{T[t]}$$I have ...
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516 views

### ReplaceAll (/.) not working as expected

I am trying to replace some variables in the form of n*wt with wt. However, I came across some cases where the ...
• 1,257
311 views

### Definition of a general rule

By defining: rule = Sqrt[expr_^2] :> expr; and writing: Sqrt[x^2] /. rule I get: x which is what is desired (...
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36 views

### Parsing time interval strings as "Uncertain" Time Intervals

Problem: I have strings of form "[d1, d2]" or sometimes just [d1] where d1 and ...
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1k views

### How to find multi-word synonyms?

I’m looking to write a semantic distance function for phrases (5 words or less) that can map multi-word synonyms together. My domain is e-commerce fashion - here are some required examples for a ...
• 30.3k
168 views

### Using Semantic Import to do an Excel-like VLookUp using Mathematica

I'm following an example provided in the following Stack Exchange Link but, using a different approach. My data is contained in an Excel workbook called "Input Workbook.xlsx" as shown here: I ...
141 views

### Identify complex expression and replace

I'm having trouble finding a way (if there is) to analyse an expression, identify a complex pattern in it and then replace it with another thing. I think it will be easier to explain my problem with ...
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160 views

### "Smart" substitution of subexpressions

I have the following question. An expression, which I want to simplify contains several subexpressions which appear quite frequently all over the place. To optimize simplification I would like to ...
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122 views

### SemanticImport extremely slow with "Number" format

With the following definition: col = "num\n" <> StringRiffle[Table[i, {i, 1000}], "\n"]; I do not understand why the ...
153 views

### Sets of identical equality/inequalities

So I've used Mathematica for some months, but I never noticed this sort of thing about it, namely: (a > b) == (b < a) which are supposed to be identical ...
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179 views

### Simplifying expressions

Let's define a function $\Omega(x,y)$ ...
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