Python – Maximum in Row Range

When it is required to find the maximum value in a row range, a simple iteration and the max() method is used.

Example

Below is a demonstration of finding the maximum value across specified rows ?

my_list = [[11, 35, 6], [9, 11, 3], [35, 4, 2], [8, 15, 35], [5, 9, 18], [5, 14, 2]]

print("The list is :")
print(my_list)

i, j = 2, 4
print("The row range values are")
print(i, j)

my_result = 0
for index in range(i, j):
    my_result = max(max(my_list[index]), my_result)

print("The maximum value in row range is :")
print(my_result)

Output

The list is :
[[11, 35, 6], [9, 11, 3], [35, 4, 2], [8, 15, 35], [5, 9, 18], [5, 14, 2]]
The row range values are
2 4
The maximum value in row range is :
35

How It Works

• A list of lists is defined with 6 rows of data
• The range values i=2 and j=4 specify rows 2 and 3 (indices 2 to 3)
• The algorithm iterates through the specified row range
• For each row, max(my_list[index]) finds the maximum value in that row
• The outer max() compares this with the current result to keep the overall maximum
• Row 2: [35, 4, 2] ? max = 35
• Row 3: [8, 15, 35] ? max = 35
• Overall maximum = 35

Alternative Approach Using List Comprehension

You can achieve the same result more concisely using list comprehension ?

my_list = [[11, 35, 6], [9, 11, 3], [35, 4, 2], [8, 15, 35], [5, 9, 18], [5, 14, 2]]

i, j = 2, 4
result = max(max(row) for row in my_list[i:j])

print(f"Maximum value in rows {i} to {j-1}: {result}")

Maximum value in rows 2 to 3: 35

Conclusion

Use nested max() functions to find the maximum value across a specific row range in a 2D list. The list comprehension approach provides a more concise solution for the same problem.