Session and time information

The “time” function and variable

Pine provides means to work with trade session, time and date information. On this IBM chart at 30 minutes, two scripts are running: “Bar date/time” and “Session bars”.

../_images/Chart_time_1.png

This is the “Bar date/time” script:

//@version=4
study("Bar date/time")
plot(time)

The time variable returns the date/time (timestamp) of each bar’s opening time in UNIX format [1] and in the exchange’s timezone. As can be seen from the screenshot, the time value on the last bar is equal to 1397593800000. This value is the number of milliseconds that have passed since 00:00:00 UTC, 1 January, 1970 and corresponds to Tuesday, 15th of April, 2014 at 20:30:00 UTC. The chart’s time gauge in the screenshot shows the time of the last bar as 2014-04-15 16:30 because it has a 4-hour difference between the exchange’s timezone, which is the default time returned by the time function.

The second script is “Session bars”:

//@version=4
study("Session bars")
t = time(timeframe.period, "0930-1600")
plot(na(t) ? 0 : 1)

This shows how the user can distinguish between regular session and extended hours bars by using the built-in time function rather than the time variable. Note that the background behind these bars is colored because of the chart’s settings; not because of the script. The time function returns the time of the bar’s start in milliseconds UNIX time, or na if the bar is located outside the given trade session (09:30–16:00 in our example). The time function accepts two arguments: the resolution used to determine the timestamp of bars and session, the session specification in the form of a string containing the beginning and end of the trade session in the exchange’s timezone. The string “0930-1600” corresponds to the trade session of the IBM symbol. These are examples of trade session specifications:

0000-0000
A monday to friday 24-hour session beginning at midnight.
0900-1600,1700-2000
A session that begins at 9:00, breaks from 16:00 to 17:00 and continues until 20:00. Applies to Monday through Friday.
2000-1630:1234567
An overnight session that begins at 20:00 and ends at 16:30 the next day.
0930-1700:146
A session that begins at 9:30 and ends at 17:00 on Sundays (1), Wednesdays (4) and Fridays (6) (other days of the week are days off).
24x7
A complete 24-hour session beginning at 00:00 every day.
0000-0000:1234567
Same as “24x7”.
0000-0000:23456
Same as previous example, but only Monday to Friday.
1700-1700:23456
An overnight session. Monday session starts Sunday at 17:00 and ends Monday at 17:00. Applies to Monday through Friday. Equivalent to 1700-1700
1000-1001:26
A weird session that lasts only one minute on Mondays (2) and one minute on Fridays (6).

Session specification used for the time function’s second argument does not need to correspond to the symbol’s real trade session. Hypothetical session specifications can be used to highlight other bars of a data series.

Pine provides an overloaded version of the time function which does not require custom session specification. This version of the function uses the regular session of a symbol. For example, it is possible to highlight the beginning of each half-hour bar on a minute chart in the following way:

//@version=4
study("new 30 min bar")
is_newbar(res) =>
    t = time(res)
    not na(t) and (na(t[1]) or t > t[1])
plot(is_newbar("30") ? 1 : 0)
../_images/Chart_time_2.png

The previous example’s is_newbar custom function can be used in many situations. Here, we use it to display the market’s opening high and low on an intraday chart:

//@version=4
study("Opening high/low", overlay=true)

highTimeFrame = input("D", type=input.resolution)
sessSpec = input("0930-1600", type=input.session)

is_newbar(res, sess) =>
    t = time(res, sess)
    na(t[1]) and not na(t) or t[1] < t

newbar = is_newbar("1440", sessSpec)

var float s1 = na
var float s2 = na
if newbar
    s1 := low
    s2 := high

plot(s1, style=plot.style_circles, linewidth=3, color=color.red)
plot(s2, style=plot.style_circles, linewidth=3, color=color.lime)
../_images/Chart_time_3.png

Pay attention to the variables highTimeFrame and sessSpec. They are defined using the input function and its type parameter to make their type explicit.

Built-in variables for working with time

Pine’s standard library has an assortment of built-in variables and functions which make it possible to use time in the script’s logic.

The most basic variables:

  • time — UNIX time of the current bar start in milliseconds, UTC timezone.
  • timenow — Current UNIX time in milliseconds, UTC timezone.
  • syminfo.timezone — Exchange timezone of the chart main symbol series.

Variables that give information about the current bar start time:

  • year — Current bar year.
  • month — Current bar month.
  • weekofyear — Week number of current bar.
  • dayofmonth — Date of current bar.
  • dayofweek — Day of week for current bar. You can use sunday, monday, tuesday, wednesday, thursday, friday and saturday variables for comparisons.
  • hour — Hour of the current bar start time (in exchange timezone).
  • minute — Minute of the current bar start time (in exchange timezone).
  • second — Second of the current bar start time (in exchange timezone).

Functions for UNIX time “construction”:

  • year(t) — Returns year for provided UTC time t.
  • month(t) — Returns month for provided UTC time t.
  • weekofyear(t) — Returns week of year for provided UTC time t.
  • dayofmonth(t) — Returns day of month for provided UTC time t.
  • dayofweek(t) — Returns day of week for provided UTC time t.
  • hour(t) — Returns hour for provided UTC time t.
  • minute(t) — Returns minute for provided UTC time t.
  • second(t) — Returns second for provided UTC time t.
  • timestamp(year, month, day, hour, minute) — Returns UNIX time of specified date and time. Note, there is also an overloaded version with an additional timezone parameter.

All these variables and functions return time in the exchange time zone, except for the time and timenow variables which return time in UTC timezone.

Footnotes

[1]UNIX time is measured in seconds. Pine Script uses UNIX time multiplied by 1000, so it’s in millisecods.
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