How to write a linear search algorithm in Python?

How to write a linear search algorithm in Python?

Linear search is one of the simplest search algorithms, also known as sequential search. Its principle is very simple, that is, it traverses the data set to be searched from beginning to end, and compares the search target with the elements in the data set one by one.

Below we will introduce how to use Python to write a linear search algorithm and give specific code examples.

1. Algorithm implementation steps:

   • Traverse the data set to be found and compare targets and elements one by one.
   • If the target is found, return the index position of the element.
   • If the target is not found after traversing all elements, -1 will be returned.

2. Code example:

   def linear_search(arr, target):
    for i in range(len(arr)):
        if arr[i] == target:
            return i
    return -1
   
   # 测试代码
   arr = [1, 2, 3, 4, 5]
   target = 3
   
   result = linear_search(arr, target)
   if result != -1:
    print("目标元素在索引位置：", result)
   else:
    print("未找到目标元素")

The above code implements a simple linear search algorithm. First define a linear_search function, which accepts two parameters: one is the data set to be found arr, and the other is the target element target.

Next, iterate through each element in arr through a for loop and compare it with target. If the target element is found, the index position of the element is returned. If the target element is not found after the traversal is completed, -1 is returned.

In the test code section, we define a sample data collection arr and the target element target, and then call the linear_search function to search. Finally, the corresponding prompt information is output according to the return result of the function.

Please note that the time complexity of the linear search algorithm is O(n), where n is the size of the data set to be found. Linear search algorithms may be less efficient when the data collection is large because all elements need to be compared one by one.

Summary:
It is very simple to write a linear search algorithm in Python. You only need to traverse the data set to be found and compare it with the target element one by one. With the above code examples, we can easily understand and implement the linear search algorithm.

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