问计算Pine Script数组中每个元素的变化

EN

//@version=4
study("My Script")

pct_change(source, period) =>
    now = source
    then = source[period]
    missing_now = na(now)
    missing_then = na(then)
    
    if not missing_now and not missing_then
        (now - then) / abs(then)
    else
        missing_now ? 0 : 1

evaluate(sources) =>
    s = array.size(sources)
    bar_changes = array.new_float()
    for i = 0 to 99999
        if i < s
            source = array.get(sources, i)
            array.push(bar_changes, pct_change(source, 1))
            continue
        else
            break
    bar_changes

features = array.new_float()
array.push(features, open)
array.push(features, high)
array.push(features, close)
bar_changes = evaluate(features)

plot(pct_change(open, 1))
plot(array.get(bar_changes, 0))
plot(pct_change(high, 1), color=color.aqua)
plot(array.get(bar_changes, 1), color=color.aqua)
plot(pct_change(close, 1), color=color.red)
plot(array.get(bar_changes, 2), color=color.red)