Implementing Technical Indicators: ROC

Programming Technical Indicators R ROC
December 22, 2017

Introduction

In this part of my series Implementing Technical Indicators I provide you with the R implementation of another technical indicator. Please refer to my article Technical Indicators: An Introduction for an overview of the concept of technical indicators and for details on the particular one presented in this article.

DISCLAIMER: None of the below is intended to be considered as any kind of investment advice. All examples serve as illustrative material only.

Implementation

For an implementation of the rate of change (ROC) please see the R code below. The function ROC calculates the indicator values, which may afterwards be plotted with help of the function plotROC. Note that both function use tools introduced in my article Implementing Technical Indicators: Tools. 


#
# RATE OF CHANGE
#

source("Indicators/IndicatorHelperFunctions.R")
source("Indicators/IndicatorPlottingFunctions.R")

# indicator calculation
ROC = function(v_values, i_lag)
{
  checkWindow(v_values, i_lag)
  
  i_length = length(v_values)
  
  v_roc = rep(0, i_length)
  v_roc[1] = 0
  
  for (i in 2 : i_length) {
    if (i <= i_lag) {
      v_roc[i] = v_values[i] / v_values[1] - 1
    } else {
      v_roc[i] = v_values[i] / v_values[i-i_lag] - 1
    }
  }
  
  df_roc = data.frame(v_roc, v_values)
  colnames(df_roc) = c("ROC", "Price")
  
  return(df_roc)
}

# indicator plotting
plotROC = function(v_date, df_roc, s_path)
{
  isDataFrame(df_roc)
  dateMatch(v_date, df_roc)
  
  v_colors = c("black", "blue")
  v_legend = c("ROC", "Price")
  
  plotIndicator2(v_date, df_roc$ROC, data.frame(df_roc[, -1]), v_colors, v_legend, s_path)
}