CSV.foreach Not Reading First Column in CSV File - ruby

Question

Learning Ruby for the first time to automate cleaning up some CSV files.
I've managed to piece together the script below from other SO questions but for some reason the script does not read the first column of the original CSV file. If I add a dummy first column everything works perfectly. What am I missing?
require 'csv'
COLUMNS = ['SFID','Date','Num','Transaction Type']
CSV.open("invoicesfixed.csv", "wb",
:write_headers=> true,
:headers => ["Account__c","Invoice_Date__c","Invoice_Number__c","Transaction_Type__c"]) do |csv|
CSV.foreach('invoices.csv', :headers=>true, :converters => :all) do |row|
#convert date format to be compatible with Salesforce
row['Date'] = Date.strptime(row['Date'], '%m/%d/%y').strftime('%Y-%m-%d')
csv << COLUMNS.map { |col| row[col] }
end
end
This input file:
Transaction Type,Date,Num,SFID
Invoice,7/1/19,151466,SFID1
Invoice,7/1/19,151466,SFID2
Invoice,7/1/19,151466,SFID3
Invoice,7/1/19,151466,SFID4
Invoice,7/1/19,151466,SFID5
Invoice,7/1/19,151466,SFID6
Invoice,7/1/19,151153,SFID7
Sales Receipt,7/1/19,149487,SFID8
Sales Receipt,7/1/19,149487,SFID9
Sales Receipt,7/1/19,149758,SFID10
Sales Receipt,7/1/19,149758,SFID11
Yields this output:
Account__c,Invoice_Date__c,Invoice_Number__c,Transaction_Type__c
SFID1,2019-07-01,151466,
SFID2,2019-07-01,151466,
SFID3,2019-07-01,151466,
SFID4,2019-07-01,151466,
SFID5,2019-07-01,151466,
SFID6,2019-07-01,151466,
SFID7,2019-07-01,151153,
SFID8,2019-07-01,149487,
SFID9,2019-07-01,149487,
SFID10,2019-07-01,149758,
SFID11,2019-07-01,149758,
However, this input:
Dummy,Transaction Type,Date,Num,SFID
,Invoice,7/1/19,151466,SFID1
,Invoice,7/1/19,151466,SFID2
,Invoice,7/1/19,151466,SFID3
,Invoice,7/1/19,151466,SFID4
,Invoice,7/1/19,151466,SFID5
,Invoice,7/1/19,151466,SFID6
,Invoice,7/1/19,151153,SFID7
,Sales Receipt,7/1/19,149487,SFID8
,Sales Receipt,7/1/19,149487,SFID9
,Sales Receipt,7/1/19,149758,SFID10
,Sales Receipt,7/1/19,149758,SFID11
Yields the correct output of:
Account__c,Invoice_Date__c,Invoice_Number__c,Transaction_Type__c
SFID1,2019-07-01,151466,Invoice
SFID2,2019-07-01,151466,Invoice
SFID3,2019-07-01,151466,Invoice
SFID4,2019-07-01,151466,Invoice
SFID5,2019-07-01,151466,Invoice
SFID6,2019-07-01,151466,Invoice
SFID7,2019-07-01,151153,Invoice
SFID8,2019-07-01,149487,Sales Receipt
SFID9,2019-07-01,149487,Sales Receipt
SFID10,2019-07-01,149758,Sales Receipt
SFID11,2019-07-01,149758,Sales Receipt
Any ideas why this might be happening?

Answer 1

I had a similar problem, though running your example worked.
I realized that problem (at least for me) was that I was creating CSV file using "Save As UTF-8 CSV" from Excel.
This adds BOM to the beginning of the file - before the first column header name and consequently row['firstColumnName'] was returning nil.
Saving file as CSV fixed the issue for me.