Finding the Minimum of Non-Zero Groups using Python

The group in Python is defined by sets or collections of element that have the same characteristics based on specific conditions or operations. The group can be represented by lists, sets, or other data structures. In this problem statement, the non−zero group refers subset of the list where all the elements are non−zero and adjacent to each other without any zero value in between. In Python, we have some built−in functions like list(), groupby(), lambda, etc. will be used to solve the minimum of non−zero groups.

Syntax

The following syntax is used in the examples

list()

list() is a built−in method in Python that can be used for multiple elements in a single variable.

groupby()

The groupby() is an in−built method in Python that pass the parameter to add the name of the variable to group.

lambda

The function lambda offers a shortcut for declaring brief anonymous functions using the lambda keyword. The lambda functions behave when expressed with the def keyword.

range()

The range() is a built−in function in Python that returns the sequence of elements between a given range. By default, the initial range always starts with 0 and ends by assigning a specific range.

len()

The len() is a built−in function in Python that returns the length of the object.

min()

The min() is an in−built function in Python that returns the minimum element from the non−zero group.

append()

The append() is a built−in method in Python that adds the element at the end of the list.

join()

The join() is a built−in method in Python that accepts the iterable element by a separated string.

map()

In Python, the map() function allows us to process all the elements from the list, and by transforming it will iterate all the elements without using of explicit for loop.

split()

The split() is an in−built function in Python that separate the string into a list of string.

Using itertools

In the following example, the program uses the Python itertools module that helps provide complex iteration by using built−in functions− groupby() and lambda and these processes find the minimum non−zero group.

Example

import itertools
def minimum_nonzero(lst):
    non_zero_groups = [list(group) for key, group in itertools.groupby(lst, key=lambda x: x != 0) if key]
    min_values = [min(group) for group in non_zero_groups]
    return non_zero_groups, min_values
# Create the non-group of list element
lst = [2, 9, 0, 0, 0, 3, 1, 0, 0, 5, 0, 0, 9, 0]
# Calling function sets to two variables
groups, min_values = minimum_nonzero(lst)
for i in range(len(groups)):
    print(f"Group: {groups[i]}, Minimum Value: {min_values[i]}")

Output

Group: [2, 9], Minimum Value: 2
Group: [3, 1], Minimum Value: 1
Group: [5], Minimum Value: 5
Group: [9], Minimum Value: 9

Using min() and append() function

In the following example, the program uses the built−in function min() to find the lowest among non−zero group whereas the append() function add the element to the group.

Example

def min_group_nonzero(lst):
    def min_group(lst):
        group = []
        for num in lst:
            if num == 0:
                if group:
                    yield group, min(group)
                    group = []
            else:
                group.append(num)
        if group:
            yield group, min(group)    
    return list(min_group(lst))
# Create the list for non-zero group
lst = [1, 2, 3, 0, 0, 0, 0, 4, 5, 0, 0, 0, 23, 44, 0, 2]
# Calling function
result = min_group_nonzero(lst)
# Print the group element and minimum value from non-zero group
for group, min_value in result:
    print(f"Group: {group}, Minimum Value: {min_value}")

Output

Group: [1, 2, 3], Minimum Value: 1
Group: [4, 5], Minimum Value: 4
Group: [23, 44], Minimum Value: 23
Group: [2], Minimum Value: 2

Using list comprehension

In the following example, the program uses list comprehension where some of the built−in functions such as join(), split(), and, min() will be used to find the minimum non−zero group.

Example

def min_nonzero_groups_2(lst):
    non_zero_groups = [list(group) for group in ''.join(map(str, lst)).split('0') if group]
    min_values = [min(group) for group in non_zero_groups]
    return non_zero_groups, min_values
# Create the non-zero list
lst = [0, 0, 0, 1, 2, 9, 0, 0, 5, 2, 3]
groups, min_values = min_nonzero_groups_2(lst)
# Print the group along with minimum value
for i in range(len(groups)):
    print(f"Group Element: {groups[i]}, Minimum Value: {min_values[i]}")

Output

Group Element: ['1', '2', '9'], Minimum Value: 1
Group Element: ['5', '2', '3'], Minimum Value: 2

Conclusion

The minimum non−zero group is the specific task to find the minimum value from the group element. There were used methods such as list comprehension, itertools module, min(), and, append() to solve the problem statement. There are few examples of non−zero groups are− Data Analysis, Signal Processing, Time series analysis, Data cleaning and preprocessing etc.