The Shunting Yard Algorithm Demystified: Transform Expressions Like a Pro!

Welcome to my in-depth tutorial on the Shunting Yard Algorithm! 🚂💻 In this video, I unpack and explain this intriguing and useful algorithm. Designed by Edsger Dijkstra, this algorithm is a cornerstone for understanding expression evaluation and conversion, as it converts infix expressions to postfix (or Reverse Polish Notation) expressions.
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Source code: github.com/garyexplains/examp...
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[@tommurphy7157]

Brilliantly explained and very timely! Just what I needed to create the 'advanced' search for my app

[@bendono]

I used RPN on my HP48G calculator while in high school. I also learned the Shunting Yard algorithm in my Computer Science degree; however, I guess I never really understood what "shunting yard" meant. It seems to be the British expression for a rail yard. I don't think it is a common term in US English. I recall classmates jokingly interpret it as "shatting yard" as in a place to to take shit.

[@nickeax]

Thank you for the great presentation.

[@muddyexport5639]

Excellent explanation and demo.

[@GaryExplains]

Glad you liked it!

[@user-jv1js9oc8l]

This was perfect timing thank you!

[@GaryExplains]

So glad!

[@alejandroguardiola9085]

Great video, but I have a question, in the explanation it seems like the output is a queue instead of a stack?

[@berjancemdarc4345]

What would this code do on situations like 10+2 ?

[@bertblankenstein3738]

Once upon a time I coded a stack and the operators were numbers in an array of pointers to functions. I was kind of hoping to learn how this relates to railyards tho.

[@kenc4026]

Great work, sir. I got an idea because of this. Does this logic applies to Boolean Algebra too?

[@cxrbon637]

i think so

[@Garythefireman66]

Thanks professor! 🤓

[@GaryExplains]

My pleasure!

[@AlwaysCensored-xp1be]

I wonder if LLM can solve those model train shunting games?

[@HyyskanPolttaja]

Great! But what about square roots & stuff?

[@GaryExplains]

For other operations you would use functions like cos (), sqrt(), etc. This is how you could write a compiler or interpreter using this method. It is the same principle. Functions have a lower precedence than plus and minus. Raise-to-power ^ has the highest precedence.

[@uvatham]

00:06

[@GaryExplains]

🚂

[@jameslewis7620]

🤣

[@CanadianBakin42O]

FÍRST!

[@sssyt4837]

First!

[@K9-33]

Just use the FORTH programming language.

[@GaryExplains]

That isn't the point. The point is to know how to do it yourself.

[@LA-MJ]

Exit takes an exit code not a calculation result 😂

[@GaryExplains]

And why can't the exit code be a calculation result?

[@LA-MJ]

@@GaryExplainsbecause non-zero exit code means error occurred in standard semantics

[@GaryExplains]

No, not necessarily. If you want a program to calculate something it can return the calculation as an exit code. This is very useful for scripting. You are making an assumption about the return codes, I assume based on Unix/Linux. On VMS for example SUCCESS was never 0.

[@LA-MJ]

@@GaryExplainsof course it's UNIX. Which matters more