# Linear Search — Data Structures & Algorithms

Source: https://www.geekswithgeeks.com/en/dsa/linear-search

> Check every element until you find the target. O(n), works on any data.

## The baseline

Walk left to right, comparing each item. Best case `O(1)` (first slot), worst and average `O(n)`. No sorting or extra memory required — the fallback when nothing else applies.

## Implementation

Return the index, or -1 if absent.

```python
def linear_search(arr, target):
    for i, x in enumerate(arr):
        if x == target:
            return i
    return -1
```

## When it's the right call

Small or unsorted data, linked lists (no random access), or when you'd spend more sorting than searching once.