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Brian_Alexander
Asked: 2020-05-10 05:25:25 +0800 CST 2020-05-10 05:25:25 +0800 CST

How do I update the key and value of a hash in Ruby?

  • 772

Turns out I have a hash :

inventario = {"Notebooks"=> 4, "PC Escritorio"=> 6, "Routers"=> 10, "Impresoras"=> 6}

I need to update the information regarding any product, and for the inventory to be updated.

I tried with map, hashmapand put, but it seems I'm not using them correctly.

ruby

1 Answers

  1. Best Answer

    To update the value of a key in a hash, simply assign a new value directly using the Hash#[]= method ; for instance:

    inventario = { "Notebooks"=> 4, "PC Escritorio"=> 6, "Routers"=> 10, "Impresoras"=> 6 }
#=> {"Notebooks"=>4, "PC Escritorio"=>6, "Routers"=>10, "Impresoras"=>6}

    To change inventory from "Notebooks"to 5:

    inventario["Notebooks"] = 5
#=> 5

inventario
#=> {"Notebooks"=>5, "PC Escritorio"=>6, "Routers"=>10, "Impresoras"=>6}

    Since the values ​​are numbers, you can use +or -; For example, if you sell 2 "Impresoras"(inventory decrease), you could do the following:

    inventario["Impresoras"] -= 2
#=> 4

inventario
#=> {"Notebooks"=>5, "PC Escritorio"=>6, "Routers"=>10, "Impresoras"=>4}

    Finally, you can substitute values ​​for variables, assuming they come from another section of code in your application; for instance:

    producto = "Routers"
items_vendidos = 3

inventario[producto] -= items_vendidos
#=> 7

inventario
#=> {"Notebooks"=>5, "PC Escritorio"=>6, "Routers"=>7, "Impresoras"=>4}
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