Append to empty list in python-CodePudding

I'm pretty new to Python and have a task where I am supposed to iterate through a sorted list to find the place where to insert an element into the list at the right place. So far I have managed to get it to work, except for when the list is empty. I have tried to read up on the "append"-function to see how I can do to not make it print "None", but without any results.

If someone has a good answer to how I can adjust the first if-statement to make it possible to add the value x to the list and print the updated list it would be amazing. I want the first test with the (2, []) to show [2].

# Task 1a
# Create a function that places an element x in a sorted list

def insert_in_sorted (x, sorted_list):
    for i in range(len(sorted_list)):
        if not sorted_list:
            sorted_list.append(x)
            return sorted_list
        if x > max(sorted_list) or not sorted_list:
            sorted_list.append(x)
            return sorted_list
        elif sorted_list[i] > x:
            sorted_list.insert(i,x)
            return sorted_list
        elif sorted_list[i-1] and sorted_list[i 1] == x:
            sorted_list.insert(i,x)
            return sorted_list

print(insert_in_sorted(2,[]))
print(insert_in_sorted(5,[0,1,3,4]))
print(insert_in_sorted(2,[0,1,2,3,4]))
print(insert_in_sorted(2,[2,2]))

CodePudding user response：

your look will only iterate if there are items in the list, so just take the first if outside the loop to check if the list is empty or not

# Task 1a
# Create a function that places an element x in a sorted list

def insert_in_sorted(x, sorted_list):
    if not sorted_list:
        sorted_list.append(x)
        return sorted_list
    
    for i in range(len(sorted_list)):
        if x > max(sorted_list) or not sorted_list:
            sorted_list.append(x)
            return sorted_list
        elif sorted_list[i] > x:
            sorted_list.insert(i, x)
            return sorted_list
        elif sorted_list[i - 1] and sorted_list[i   1] == x:
            sorted_list.insert(i, x)
            return sorted_list


print(insert_in_sorted(2, []))
print(insert_in_sorted(5, [0, 1, 3, 4]))
print(insert_in_sorted(2, [0, 1, 2, 3, 4]))
print(insert_in_sorted(2, [2, 2]))

OUTPUT

[2]
[0, 1, 3, 4, 5]
[0, 1, 2, 2, 3, 4]
[2, 2, 2]

CodePudding user response：

it seems you are doing left insert

import bisect
def insert_in_sorted (x, sorted_list):

    bisect.insort_left(sorted_list,x)
    return sorted_list

print(insert_in_sorted(2,[]))
print(insert_in_sorted(5,[0,1,3,4]))
print(insert_in_sorted(2,[0,1,2,3,4]))
print(insert_in_sorted(2,[2,2]))

[2]
[0, 1, 3, 4, 5]
[0, 1, 2, 2, 3, 4]
[2, 2, 2]