Python · Theory

Linear Search in Python

Theory

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Linear Search in Python

Linear search checks each item from start to end until it finds the target. Works on unsorted lists. Worst case you look at all n items — O(n). Code is a for-loop and an if. Acceptable on small lists or when data is not sorted. On a huge sorted list, binary search is the better story.

Trace [4, 1, 3, 2] looking for 3: check 4, check 1, check 3 — found. Say O(n) honestly. Don’t claim it is “always slow” — for n=10 it is fine.

Linear Search in Python — output — 1. 90 is at index 1. If missing, found stays -1.

Exam tip

When linear search is acceptable.

Example

# Linear search
marks = [70, 90, 80]
key = 90
found = -1
for i, x in enumerate(marks):
    if x == key:
        found = i
        break
print(found)

Linear Search in Python — output: 1. 90 is at index 1. If missing, found stays -1.

Short notes

DefScan one by one.
RuleWorks unsorted. O(n).
RememberEasy to code.

Python · Theory

Linear Search in Python

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Theory

75/268

Linear Search in Python

Trace [4, 1, 3, 2] looking for 3: check 4, check 1, check 3 — found. Say O(n) honestly. Don’t claim it is “always slow” — for n=10 it is fine.

Linear Search in Python — output — 1. 90 is at index 1. If missing, found stays -1.

Exam tip

When linear search is acceptable.

Example

# Linear search
marks = [70, 90, 80]
key = 90
found = -1
for i, x in enumerate(marks):
    if x == key:
        found = i
        break
print(found)

Linear Search in Python — output: 1. 90 is at index 1. If missing, found stays -1.

Short notes

DefScan one by one.
RuleWorks unsorted. O(n).
RememberEasy to code.

Linear Search in Python

Example

Short notes

Questions

Linear Search in Python

Example

Short notes

Questions