Just like strings, the list data type has several useful methods. For example, read help(list.append), help(list.insert) and help(list.extend) to see the documentation of some of the methods that modify lists. Modifying methods and operations for mutable sequence types (i.e., list) are summarised in this section of the python documentation.Below is an attempt to write a function, make_list_of_lists, that creates a list of n lists of increasing ranges of integers. The first entry in the returned list should be an empty list, the second a list of length one, ending with the number 1, and so on. For example, make_list_of_lists(3) should return [ [], [1], [1, 2] ]. (Note that n must be a non-negative integer.) However, this function is incorrect. Locate the error in the function and fix it so it works.The required output is:[][[]][[], [1], [1, 2], [1, 2, 3], [1, 2, 3, 4]]Your code1def make_list_of_lists(n):2 the_list = []3 sublist = []4 while n > 0:5 the_list.append(sublist)6 sublist.append(len(sublist) + 1)7 n = n - 18 return the_list
Question
Just like strings, the list data type has several useful methods. For example, read help(list.append), help(list.insert) and help(list.extend) to see the documentation of some of the methods that modify lists. Modifying methods and operations for mutable sequence types (i.e., list) are summarised in this section of the python documentation.Below is an attempt to write a function, make_list_of_lists, that creates a list of n lists of increasing ranges of integers. The first entry in the returned list should be an empty list, the second a list of length one, ending with the number 1, and so on. For example, make_list_of_lists(3) should return [ [], [1], [1, 2] ]. (Note that n must be a non-negative integer.) However, this function is incorrect. Locate the error in the function and fix it so it works.The required output is:[][[]][[], [1], [1, 2], [1, 2, 3], [1, 2, 3, 4]]Your code1def make_list_of_lists(n):2 the_list = []3 sublist = []4 while n > 0:5 the_list.append(sublist)6 sublist.append(len(sublist) + 1)7 n = n - 18 return the_list
Solution
The error in the function is that it is appending the same sublist to the_list in each iteration. Since sublist is mutable, when it is modified in the next iteration, the change is reflected in all previous entries in the_list where sublist was appended.
To fix this, you need to append a copy of sublist to the_list in each iteration. You can create a copy of a list in Python using the list() function or the slicing operator [:]. Here is the corrected function:
def make_list_of_lists(n):
the_list = []
sublist = []
while n > 0:
the_list.append(list(sublist)) # append a copy of sublist
sublist.append(len(sublist) + 1)
n = n - 1
return the_list
Now, make_list_of_lists(3) will return [ [], [1], [1, 2] ] as expected.
Similar Questions
7. What is the purpose of the range() function in Python when iterating over a list? A) To create a new list with a range of numbers B) To return a boolean value indicating if a list contains a specific value C) To return an iterator that generates a sequence of numbers D) To modify the elements in a list 38. What is the difference between a parameter and an argument in Python functions? A) There is no difference, the terms can be used interchangeably B) A parameter is a variable declared in a function, while an argument is the value passed to the function when it is called C) An argument is a variable declared in a function, while a parameter is the value passed to the function when it is called D) A parameter is a required value in a function, while an argument is optional
list, tuple, and range are the ___ of Data Types.Sequence TypesBinary TypesBoolean TypesNone of the mentioned above
Consider a list (list = []). You can perform the following commands:insert i e: Insert integer at position .print: Print the list.remove e: Delete the first occurrence of integer .append e: Insert integer at the end of the list.sort: Sort the list.pop: Pop the last element from the list.reverse: Reverse the list.Initialize your list and read in the value of followed by lines of commands where each command will be of the types listed above. Iterate through each command in order and perform the corresponding operation on your list.Example: Append to the list, .: Append to the list, .: Insert at index , .: Print the array.Output:
Which Python method adds an item to the end of a list?
What will be the output of below Python code?list1=["tom","mary","simon"]list1.insert(5,8)print(list1) ["tom", "mary", "simon", 5]["tom", "mary", "simon", 8][8, "tom", "mary", "simon"]Error
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