Python 对数组进行给定范围的三向划分

给定一个数组和数组的范围[startval, endval]，将数组分为三部分。

所有小于startval的元素排在最前面。
所有在startval和endval之间的元素排在其后。
所有大于endval的元素排在最后面。

假设我们有以下输入 –

A = [1, 14, 51, 12, 4, 2, 54, 20, 87, 98, 3, 1, 32]
startval = 14, endval = 54

输出应为 −

A = [1, 12, 4, 2, 3, 1, 14, 51, 20, 32,54, 87, 98]

数组的三分法：使用列表推导法

在这个示例中，我们将看到如何在给定范围内对数组进行三分法-

示例

def partition_array(input, lowVal, highVal):
    # Separate input list in three parts
    my_first = [ num for num in input if num<lowVal ]
    my_second = [ num for num in input if (num>=lowVal and num<=highVal) ]
    my_third = [ num for num in input if num>highVal ]
    # Concatenate all the three parts
    print(my_first + my_second + my_third)

# Driver program
if __name__ == "__main__":
    my_input = [10, 140, 50, 200, 40, 20, 540, 200, 870, 980, 30, 10, 320]
    my_lowVal = 140
    my_highVal = 200
    partition_array(my_input, my_lowVal, my_highVal)

输出

[10, 50, 40, 20, 30, 10, 140, 200, 200, 540, 870, 980, 320]

在while循环中将数组围绕给定范围进行三路划分

在这个示例中，我们将看到如何使用while循环将数组围绕给定范围进行三路划分 –

示例

def partitionFunc(my_input, n, lowVal, highVal):
    begn = 0
    end = n - 1
    i = 0

    # Looping
    while i <= end:
        if my_input[i] < lowVal:
            my_input[i], my_input[begn] = my_input[begn], my_input[i]
            i += 1
            begn += 1

        elif my_input[i] > highVal:
            my_input[i], my_input[end] = my_input[end], my_input[i]
            end -= 1
        else:
            i+=1

# Driver code
if __name__ == "__main__":
    my_input = [1, 14, 51, 12, 4, 2, 54, 20, 87, 98, 3, 1, 32]
    n = len(my_input)

    partitionFunc(my_input, n, 14, 54)

    for i in range(n):
        print(my_input[i], end = " ")