How do I use an r for-loop to repeatedly fill out template with each loop using data from a list

Question

I want to write a script that will take a list of daily incomes and enter these incomes into a standard XML template. which currently has a placeholder where the income value should be. The aim is to generate n, in this case 3, api ready XML products with unique date and income fields. I cannot post actual data as it is confidential, so I've generated a simplified version.

 Date Income
       <chr>  <dbl>
1 20/06/2017   2000
2 22/06/2017   3023
3 23/06/2017   4021

XML 
#
<Date>holding_date</Date>
<LineAmountTypes>Inclusive</LineAmountTypes>
<Description>total daily income</Description>
<LineAmount>holding_lineamount_value</LineAmount>
</LineItem></LineItem>
<BankAccount>
    <Code>value</Code>
</BankAccount>

I can't figure out a way, using for-loops or LApply functions, to say, generate a series of XML templates, similar to the one above, except that each contains a unique daily income where "holding_lineamount_value" is now.

I can do this manually obviously, but I need this to be reproducible for hundreds of daily incomes and dates.

Can anyone help me construct a for loop or alternative to complete this task as I'm lost?

Answer 1

It isn't very clear from your description what you would like the final XML structure to look like. But this might get you started on creating a new XML document for each row of data in your dataframe.

library(XML)

# Create function to generate an XML file
createXML <- function(x){
  # Get data from current column being processed
  holding_date <- x[1]
  holding_lineamount_value <- x[2]

  # Create main node
  xmlfile <- newXMLNode("MainXML")

  # Add nodes to main node
  xmlfile <- addChildren(xmlfile, newXMLNode("Date", holding_date))
  xmlfile <- addChildren(xmlfile, newXMLNode("LineAmountTypes", "Inclusive"))
  xmlfile <- addChildren(xmlfile, newXMLNode("Description", "total daily income"))
  xmlfile <- addChildren(xmlfile, newXMLNode("LineAmount", holding_lineamount_value))
  xmlfile <- addChildren(xmlfile, newXMLNode("LineItem"))
  xmlfile <- addChildren(xmlfile, newXMLNode("LineItems"))

  # Create BankAccount node
  ba <- newXMLNode("BankAccount")

  # Add Code node to BankAccount node
  ba <- addChildren(ba, newXMLNode("Code","value"))

  # Add BankAccount node to main node
  xmlfile <- addChildren(xmlfile, ba)

  # Return the xml file
  return(xmlfile)
}

# Create dataframe
df <- data.frame(Date = c("20/06/2017", "22/06/2017","23/06/2017"),
                 Income = c(2000,3023,4021),
                 stringsAsFactors = FALSE)

# Transpose dataframe to be processed with lapply
tdf <- as.data.frame(t(df))

# Create a list of XML files for each column of transposed dataframe
xml.list <- lapply(tdf, createXML)