Error when using SMA() function in quantmod package in R

Question

Newbie programmer here!

I'm trying to create a stock price prediction model on FAANG stocks. I've installed the quantmod package to calculate technical indicators (50/200 day SMA, RSI, MACD) and add them as variables to a data set that includes stock price and open/close prices.

FB = read.csv("FB.csv")
AAPL = read.csv("AAPL.csv")
AMZN = read.csv("AMZN.csv")
NFLX = read.csv("NFLX.csv")
GOOG = read.csv("GOOG.csv")

# We will need to manipulate the date data since it's pulling in as character strings.
FB$Date = dmy(FB$Date)
AAPL$Date = dmy(AAPL$Date)
AMZN$Date = dmy(AMZN$Date)
NFLX$Date = dmy(NFLX$Date)
GOOG$Date = dmy(GOOG$Date)

# To follow R best practices, we will need to adjust the variable names to be lowercase and replace . with _
names(FB) = c("date", "low", "open", "volume", "high", "close", "adjusted_close")
names(AAPL) = c("date", "low", "open", "volume", "high", "close", "adjusted_close")
names(AMZN) = c("date", "low", "open", "volume", "high", "close", "adjusted_close")
names(NFLX) = c("date", "low", "open", "volume", "high", "close", "adjusted_close")
names(GOOG) = c("date", "low", "open", "volume", "high", "close", "adjusted_close")

# We'll need to add technical indicators to the data set to further our analysis: 50/200 Day SMA, RSI, MACD
aapl_sma50 = SMA(Cl(AAPL), n = 50) #50 day SMA for AAPL
aapl_sma200 = SMA(Cl(AAPL), n = 200) #200 day SMA for AAPL
aapl_rsi = RSI(Cl(AAPL), n = 14) #14 day RSI for AAPL

When I run the SMA functions, I get this error message:

> aapl_sma50 = SMA(Cl(AAPL), n = 50) #50 day SMA for AAPL
Error in runSum(x, n) : ncol(x) > 1. runSum only supports univariate 'x'
> aapl_sma200 = SMA(Cl(AAPL), n = 200) #200 day SMA for AAPL
Error in runSum(x, n) : ncol(x) > 1. runSum only supports univariate 'x'
> aapl_rsi = RSI(Cl(AAPL), n = 14) #14 day RSI for AAPL

Any ideas on how to debug this?

Answer 1

Since you are already using quantmod you can use getSymbols to download the data. The below works without any error.

library(quantmod)
getSymbols(c('AAPL', 'AMZN')) #Add more symbols if needed 

aapl_sma50 = SMA(Cl(AAPL), n = 50) 
aapl_sma200 = SMA(Cl(AAPL), n = 200)
aapl_rsi = RSI(Cl(AAPL), n = 14)

Answer 2

It works without any error using the default dataset

library(quantmod)
SMA(Cl(ttrc), n = 50)