Lists & loops
Iterate, transform, and combine sequences with readable loop patterns.
Find Local Minima (Valleys) in a Numeric List in Python
This code finds indices of all local minima (valleys) in a numeric list, including edge cases, using a simple loop that compares each element with its neighbors.
def find_local_minima(numbers):
"""Find indices of local minima (valleys) in a numeric list.
A value is a local minimum if it's less than or equal to its neighbors.
Edge elements are considered minima if they're less than or equal to their single neighbor.
"""
if not numbers:
return []…How to Find Local Maxima in a Python List
Return the indices of all local maxima in a numeric list, where a peak is an element greater than both its immediate neighbors.
def find_peaks(numbers):
"""
Return the indices of local maxima in a numeric list.
A local maximum is an element greater than both its neighbors.
"""
if len(numbers) < 3:
return []
peaks = []
for i in range(1, len(numbers) - 1):
if numbers[i] > numbers[i - 1] and number…How to Swap Two Indices in a Python List
Swap two elements at given indices in a Python list using simultaneous assignment, then return the modified list.
def swap_indices(lst, i, j):
lst[i], lst[j] = lst[j], lst[i]
return lst
if __name__ == "__main__":
my_list = [10, 20, 30, 40, 50]
print("Original list:", my_list)
swapped = swap_indices(my_list, 1, 3)
print("After swapping indices 1 and 3:", swapped)Browse by section
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Lists & loops — Python code examples
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This page collects lists & loops snippets — short, copy-ready Python you can paste into our free online IDE and run without installing anything. Each sample includes a plain-English explanation and the full source code.
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