Time series data

Displaying dates and timestamps

LightningChart Python data values are described with numbers. When it comes to Time series data, timestamps must be in Unix time format, specifically milliseconds since January 1, 1970 00:00:00 UTC.

import time

current_time = time.time() # as seconds
current_time_ms = current_time * 1000 # as milliseconds

from datetime import datetime

def timestamp_str_to_unix(timestamp_str: str, timestamp_format: str):
    """ Converts a timestamp string to a Unix timestamp in milliseconds.

    Args:
        timestamp_str (str): The timestamp string that needs to be converted.
        timestamp_format (str): The format in which the timestamp string is provided.
    """
    dt = datetime.strptime(timestamp_str, timestamp_format)
    unix_ms = dt.timestamp() * 1000
    return int(unix_ms)

unix_timestamp = timestamp_str_to_unix("2023-09-06 12:30:45", "%Y-%m-%d %H:%M:%S")
unix_timestamp # 1693992645000

To display date & time values on the axis, change axis tick strategy to DateTime or Time:

axis.set_tick_strategy('DateTime')

Time series example with real-time data:

import lightningchart as lc
import time
import random

lc.set_license('my-license-key')

chart = lc.ChartXY()

chart.get_default_x_axis().dispose() # dispose the default x-axis
axis = chart.add_x_axis(axis_type='linear-highPrecision') # create new x-axis
axis.set_tick_strategy('DateTime') # configure the axis to show datetime formatted ticks,
axis.set_scroll_strategy(strategy='scrolling')  # set the axis to scroll strategy
axis.set_interval(  # configure the axis interval length, in milliseconds
    start=-10_000, # 10 seconds
    end=0,
    stop_axis_after=False  # allow the axis move as new data comes in
)

series = chart.add_line_series(
        schema={
    'x': {'pattern': 'progressive'},
    'y': {'pattern': None},
    })

chart.open(live=True)

for _ in range(1000):
    x = time.time() * 1000
    y = random.random()
    series.append_samples(samples={
            'x': [x],
            'y': [y]
        })
    time.sleep(0.01)

chart.close()