Normalize close prices to 100 — normalize_prices • golemstockindices

Every index starts at 100 on the first date on which all of them have data, so their lines can be compared directly: 150 means the price rose by half since that date.

Usage

normalize_prices(history)

Arguments

history: Price history from get_history(), with label, timestamp and close columns, sorted by index and date.

Value

history from the first common date on, with an index column.

Examples

history <- data.frame(
  label = rep(c("Alpha (A)", "Beta (B)"), each = 3),
  timestamp = rep(as.Date("2024-01-01") + 0:2, 2),
  close = c(10, 11, 12, 200, 180, 220)
)
normalize_prices(history)
#>       label  timestamp close index
#> 1 Alpha (A) 2024-01-01    10   100
#> 2 Alpha (A) 2024-01-02    11   110
#> 3 Alpha (A) 2024-01-03    12   120
#> 4  Beta (B) 2024-01-01   200   100
#> 5  Beta (B) 2024-01-02   180    90
#> 6  Beta (B) 2024-01-03   220   110