Python Pandas IntervalIndex - Get integer location for requested label

The get_loc() method in Pandas IntervalIndex returns the integer position of a specified label within the index. This is useful when you need to find where a particular value falls within your interval structure.

Syntax

IntervalIndex.get_loc(key, method=None, tolerance=None)

Parameters

key: The label to locate
method: Method for inexact matches (None, 'pad', 'backfill', 'nearest')
tolerance: Maximum distance for inexact matches

Basic Example

Let's create an IntervalIndex and find the location of a specific value ?

import pandas as pd

# Create two Interval objects
interval1 = pd.Interval(50, 75)
interval2 = pd.Interval(75, 90)

# Display the intervals
print("Interval1...")
print(interval1)
print("Interval2...")
print(interval2)

# Create IntervalIndex from the intervals
index = pd.IntervalIndex([interval1, interval2])
print("\nIntervalIndex:")
print(index)

# Get integer location for requested label
location = index.get_loc(75)
print("\nInteger location for value 75:")
print(location)

Interval1...
(50, 75]
Interval2...
(75, 90]

IntervalIndex:
IntervalIndex([(50, 75], (75, 90]], dtype='interval[int64, right]')

Integer location for value 75:
0

Multiple Intervals Example

Here's an example with more intervals to demonstrate different locations ?

import pandas as pd

# Create multiple intervals
intervals = [
    pd.Interval(0, 25),
    pd.Interval(25, 50), 
    pd.Interval(50, 75),
    pd.Interval(75, 100)
]

# Create IntervalIndex
index = pd.IntervalIndex(intervals)
print("IntervalIndex:")
print(index)

# Find locations for different values
values_to_check = [10, 30, 60, 85]

for value in values_to_check:
    location = index.get_loc(value)
    print(f"Value {value} is at index position: {location}")

IntervalIndex:
IntervalIndex([(0, 25], (25, 50], (50, 75], (75, 100]], dtype='interval[int64, right]')
Value 10 is at index position: 0
Value 30 is at index position: 1
Value 60 is at index position: 2
Value 85 is at index position: 3

How It Works

The get_loc() method searches through the IntervalIndex to find which interval contains the specified value. It returns the integer position (0-based index) of the first matching interval. For overlapping intervals, it returns the position of the first match.

Conclusion

The get_loc() method provides an efficient way to find the integer position of a value within an IntervalIndex. This is particularly useful for data analysis tasks involving time series, categorical ranges, or any interval-based data structures.