Is it possible to randomly select a pulse length using a Python lookup table?

General Discussions
1

I am working on a Python program to automate a piezoelectric droplet generator. For each pulse length, there is a corresponding range of voltages required to produce the signal needed to generate a droplet. These voltage values vary slightly in each run (e.g., ±10 units). To handle this, I maintain a database that maps each pulse length to its associated range of voltages.

For my task, I want to randomly select a pulse length within the range of 15 to 70 and retrieve the corresponding range of voltages from the lookup table. For example, if the selected pulse length is 17, the program should return a voltage range, such as 35–50, rather than a single value.

Is it possible to achieve this using a Python lookup table? If so, how can I implement it to retrieve an entire range of values instead of a single one? As a beginner in Python, I would greatly appreciate any guidance or examples.

2

Hi Ariya,

In Python, lookup tables are implemented using dictionaries. A dictionary allows you to map keys (like pulse lengths) to corresponding values (like ranges of voltages).

Here’s an example:

# Manually created lookup table
lookup_table = {
    15: [30, 35, 40, 45, 50],
    16: [31, 36, 41, 46, 51],
    17: [32, 37, 42, 47, 52],
    18: [33, 38, 43, 48, 53],
    # Add more entries as needed
}

# Retrieve the voltage range for a specific pulse length
pulse_length = 17
voltage_range = lookup_table.get(pulse_length, "Pulse length not found")
print(f"Voltage range for pulse length {pulse_length}: {voltage_range}")
3

You can dynamically generate the lookup table by mapping pulse lengths to voltage ranges using Python’s dict and range functions. This is particularly useful for large datasets:

# Dynamically generated lookup table
pulse_lengths = range(15, 71)  # Pulse lengths from 15 to 70
voltage_ranges = [range(i * 2, i * 2 + 5) for i in pulse_lengths]  # Example logic for voltage ranges

# Create a dictionary using zip
lookup_table = dict(zip(pulse_lengths, voltage_ranges))

# Retrieve the voltage range for a specific pulse length
pulse_length = 20
voltage_range = lookup_table.get(pulse_length, "Pulse length not found")
print(f"Voltage range for pulse length {pulse_length}: {list(voltage_range)}")
4

For cases where not all pulse lengths have predefined ranges, use Python’s collections.defaultdict to handle missing entries with a default logic:

from collections import defaultdict

# Default lookup table with a fallback range
default_range = lambda x: range(x * 2, x * 2 + 5)
lookup_table = defaultdict(default_range)

# Add some predefined ranges
lookup_table[15] = [35, 36, 37, 38, 39]
lookup_table[16] = [40, 41, 42, 43, 44]

# Retrieve voltage ranges
pulse_length = 18
voltage_range = lookup_table[pulse_length]
print(f"Voltage range for pulse length {pulse_length}: {list(voltage_range)}")