How to extract a part of a tick?

How to extract a part of a tick? - briefly

Use slicing or a regular expression to isolate the required portion, e.g., in Python part = tick[:n] for a fixed length or re.search(r'pattern', tick).group() for a pattern‑based extraction. This returns only the specified segment of the tick.

How to extract a part of a tick? - in detail

A tick represents the smallest measurable unit in a time‑series or a single event marker in a data set. Isolating a specific segment of that unit requires precise handling of its representation, whether it is stored as a string, a datetime object, or a numeric identifier.

First, identify the format of the tick. Common forms include:

ISO‑8601 timestamp (e.g., 2025-10-09T14:23:45.123Z);
Unix epoch with millisecond precision;
Composite string containing multiple fields separated by delimiters.

Once the format is known, apply the appropriate extraction technique:

String‑based ticks
Split the string using the delimiter that separates components.
Example in Python:
```
tick = "2025-10-09|14:23:45.123|AAPL"
date_part, time_part, symbol = tick.split("|")
```
The desired segment (e.g., the time component) is now available as time_part.
Datetime ticks
Convert to a datetime object and use attribute access or slicing.
Example in Python with pandas:
```
import pandas as pd
ts = pd.Timestamp('2025-10-09T14:23:45.123Z')
hour = ts.hour # extracts hour component
millisecond = ts.microsecond // 1000
```
For sub‑second extraction, divide microseconds by 1,000.

Numeric ticks
Apply arithmetic operations to isolate digits representing the required part.
Example in R:

tick <- 20251009142345123
date_part <- tick %/% 1e9 # integer division extracts leading digits
time_part <- (tick %% 1e9) %/% 1e3 # isolates the time component in milliseconds

SQL storage
Use built‑in functions to extract components directly in queries.
Example for PostgreSQL:

SELECT
 EXTRACT(YEAR FROM tick) AS year,
 EXTRACT(MONTH FROM tick) AS month,
 EXTRACT(DAY FROM tick) AS day,
 EXTRACT(HOUR FROM tick) AS hour,
 EXTRACT(MILLISECOND FROM tick) AS ms
FROM ticks;

Key considerations:

Preserve time‑zone information when converting timestamps; loss of offset can corrupt the extracted segment.
Validate input format before extraction to avoid runtime errors.
When processing large volumes, vectorized operations (e.g., pandas vectorized datetime methods) outperform iterative loops.

By determining the tick’s representation and applying the corresponding parsing method, a precise portion of the original marker can be retrieved efficiently.