Name Error in Excel Uninitalized Contant in ‘roo’

calendar_today Asked Mar 25, 2013
thumb_up 11 upvotes
history Updated April 14, 2026

Direct Answer

Try Roo::Excel.new Or Roo::Spreadsheet.new. This is a prose walkthrough, ranked #190th of 303 by community upvote score, from 2013.


The Problem (Q-score 3, ranked #190th of 303 in the Excel VBA archive)

The scenario as originally posted in 2013

I am trying to read an Excel file in Ruby On Rails.
I have done coding like this for reading the cell content from the Excel sheet.

def test
 require 'rubygems'
 require 'iconv'
 require 'roo'

 s = Excel.new("C:/Sites/hmmsapp/Book1.xls")
 s.default_sheet = s.sheets.first

 1.upto(4) do |line|
   roll = s.cell(line,'A')
   puts "#{roll} -------------"
 end
end

But on running this it always gives me this error.

NameError in HostelController#test

uninitialized constant HostelController::Excel

I have also included iconv as per suggestions for this problem. But there is no change in error.
Please give some light to removing this error & to read the excel file properly.

Why community consensus is tight on this one

Across 303 Excel VBA entries in the archive, the accepted answer here holds solid answer (above median) status — meaning voters are unusually aligned on the right fix.


The Verified Solution — solid answer (above median) (+11)

Verbal answer — walkthrough without a code block

Note: the verified answer is a prose walkthrough. If you need a runnable sample, check Excel VBA entries ranked in the top 10 of the same archive.

Try Roo::Excel.new

Or Roo::Spreadsheet.new


When to Use It — classic (2013–2016)

Ranked #190th in its category — specialized fit

This pattern sits in the 97% tail relative to the top answer. Reach for it when your scenario closely matches the question title; otherwise browse the Excel VBA archive for a higher-consensus alternative.

What changed between 2013 and 2026

The answer is 13 years old. The Excel VBA object model has been stable across Office 2013, 2016, 2019, 2021, 365, and 2024/2026 LTSC, so the pattern still compiles. Changes that might affect you: 64-bit API declarations (use PtrSafe), blocked macros in downloaded files (Mark-of-the-Web), and the shift toward Office Scripts for web-first workflows.

help
Frequently Asked Questions

Is this above-median answer still worth copying?
expand_more

Answer score +11 vs the Excel VBA archive median ~4; this entry is solid. The score plus 3 supporting upvotes on the question itself (+3) means the asker and 10 subsequent voters all validated the approach.

The answer has no code block — how do I turn it into a snippet?
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Use the walkthrough above as a checklist, then open a top-10 Excel VBA archive entry for a concrete starting template you can adapt.

Published around 2013 — what’s changed since?
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Published 2013, which is 13 year(s) before today’s Office 2026 build. The Excel VBA object model has had no breaking changes in that window. Three things to re-test: (1) blocked macros on downloaded files (Mark-of-the-Web), (2) 64-bit API declarations (PtrSafe, LongPtr), (3) any shift toward Office Scripts for web scenarios.

Which Excel VBA pattern ranks just above this one at #189?
expand_more

The pattern one rank above is “Setting a chart source data based on a variable cell range in VBA”. If your use case overlaps, compare both before committing.

Data source: Community-verified Q&A snapshot. Q-score 3, Answer-score 11, original post 2013, ranked #190th of 303 in the Excel VBA archive. Last regenerated April 14, 2026.