CodingBat_Lists_2_Practice_Problems.py

def function_template(nums):
    '''
        Signature: list ---> int
        Author: @Korkrid Akepanidtaworn
        Description: INSERT HERE
    '''
    pass
    
def has22(nums):
    '''
        Signature: list ---> bool
        Author: @Korkrid Akepanidtaworn
        Description: Given an array of ints, return True if the array contains a 2 next to a 2 somewhere.
        CodingBat: https://codingbat.com/prob/p119308
        
        has22([1, 2, 2]) → True
        has22([1, 2, 1, 2]) → False
        has22([2, 1, 2]) → False
    '''
    import numpy as np
    
    # This is useful when you want to access the list prior to the final one
    for w in np.arange(len(nums) - 1):
        if (nums[w] == 2) & (nums[w+1] == 2):
            return True
    
    return False

print(has22([1, 2, 2])) # → True
print(has22([1, 2, 1, 2])) # → False
print(has22([2, 1, 2])) # → False


def sum13(nums):
    '''
        Signature: list ---> int
        Author: @Korkrid Akepanidtaworn
        Description: Return the sum of the numbers in the array, returning 0 for an empty array. 
        Except the number 13 is very unlucky, so it does not count and numbers that come immediately 
        after a 13 also do not count.
        CodingBat: https://codingbat.com/prob/p167025
        
        sum13([1, 2, 2, 1]) → 6
        sum13([1, 1]) → 2
        sum13([1, 2, 2, 1, 13]) → 6
    '''
    import numpy as np
    
    total_sum = 0
    
    # Handle an empty array case
    if len(nums) == 0:
        return total_sum
    
    for v in np.arange(len(nums)):
        if nums[v] != 13:
            total_sum += nums[v]
        else:
            break # Very Unlucky Here, Just Break!
    
    return total_sum
    

print(sum13([1, 2, 2, 1])) # → 6
print(sum13([1, 1])) # → 2
print(sum13([1, 2, 2, 1, 13])) # → 6
print(sum13([])) # 0
print(sum13([1,6,7,8,13,14,1,1,1])) # 22


def big_diff(nums):
    '''
        Signature: list ---> int
        Author: @Korkrid Akepanidtaworn
        Description: Given an array length 1 or more of ints, return the difference between the 
        largest and smallest values in the array. Note: the built-in min(v1, v2) and max(v1, v2) 
        functions return the smaller or larger of two values.
        Coding Bat: https://codingbat.com/prob/p184853

        big_diff([10, 3, 5, 6]) → 7
        big_diff([7, 2, 10, 9]) → 8
        big_diff([2, 10, 7, 2]) → 8
    '''
    import numpy as np
    return np.max(nums) - np.min(nums)
    
print(big_diff([10, 3, 5, 6])) # → 7
print(big_diff([7, 2, 10, 9])) # → 8
print(big_diff([2, 10, 7, 2])) # → 8


def centered_average(nums):
    '''
        Signature: list ---> int
        Author: @Korkrid Akepanidtaworn
        Description: Return the "centered" average of an array of ints, which we'll say is the 
        mean average of the values, except ignoring the largest and smallest values in the array. 
        If there are multiple copies of the smallest value, ignore just one copy, and likewise for 
        the largest value. Use int division to produce the final average. You may assume that the 
        array is length 3 or more.
        CodingBat: https://codingbat.com/prob/p126968

        centered_average([1, 2, 3, 4, 100]) → 3
        centered_average([1, 1, 5, 5, 10, 8, 7]) → 5
        centered_average([-10, -4, -2, -4, -2, 0]) → -3
    '''
    import numpy as np
    nums_max = np.max(nums) 
    nums_min = np.min(nums)
    
    # Ignore the Largest and Smallest Values in the Array
    nums.remove(nums_max) # Remove only one although there're two maximum values...
    nums.remove(nums_min) # Remove only one although there're two minimum values...
    
    return int(np.mean(nums))
    
print(centered_average([1, 2, 3, 4, 100])) # → 3
print(centered_average([1, 1, 5, 5, 10, 8, 7])) # → 5
print(centered_average([-10, -4, -2, -4, -2, 0])) # → -3


def count_evens(nums):
    '''
        Signature: list ---> int
        Author: @Korkrid Akepanidtaworn
        Description: Return the number of even ints in the given array. 
        Note: the % "mod" operator computes the remainder, e.g. 5 % 2 is 1.
        CodingBat: https://codingbat.com/prob/p189616
        
        count_evens([2, 1, 2, 3, 4]) → 3
        count_evens([2, 2, 0]) → 3
        count_evens([1, 3, 5]) → 0
    '''
    nums_even = 0
    
    for i in range(len(nums)):
        if (nums[i] % 2) == 0:
            nums_even += 1
        else:
            continue
    
    return nums_even

print(count_evens([2, 1, 2, 3, 4])) # → 3
print(count_evens([2, 2, 0])) # → 3
print(count_evens([1, 3, 5])) # → 0


def sum67(nums):
    '''
        Signature: list ---> int
        Author: @Korkrid Akepanidtaworn
        Description: Return the sum of the numbers in the array,
        except ignore sections of numbers starting with a 6 and
        extending to the next 7 (every 6 will be followed by at least one 7).
        Return 0 for no numbers.
        CodingBat: https://github.com/snowpolar/codingbat-solutions/blob/master/Python/List-2/sum67.py
        
        sum67([1, 2, 2]) → 5
        sum67([1, 2, 2, 6, 99, 99, 7]) → 5
        sum67([1, 1, 6, 7, 2]) → 4
    '''
    record = True # To capture the positioning
    total_sum = 0 # To capture the total sum

    for n in nums:
        # If the function encounters 6
        if n == 6:
            record = False

        # If the record is True
        if record:
            total_sum += n
            continue
            
        # If the function encounters 7
        if n == 7:
            record = True

    return total_sum

print(sum67([1, 2, 2])) # → 5
print(sum67([1, 2, 2, 6, 99, 99, 7])) # → 5
print(sum67([1, 1, 6, 7, 2])) # → 4
print(sum67([])) # → 0
print(sum67([1,2,6,5,7,6,7])) # → 3