TypeError: unsupported format string passed to list.__format__
One trick is to solve this:
list
How to obtain a subarray in python 3
Use list comprehension for this
Python data structure sort list alphabetically
[] denotes a list, () denotes a tuple and {} denotes a dictionary. You should take a look at the official Python tutorial as these are the very basics of programming in Python. What you have is a list of strings. You can sort it like this: As you can see, words that start with … Read more
Appending to a list gives ‘int’ object has no attribute ‘append’
Traceback (most recent call last): File “/home/shinigami/prac5.py”, line 21, in a[i].append(p) AttributeError: ‘int’ object has no attribute ‘append’ Your variable a is a list of integers. When you write a[i].append(…) you’re trying to call an append method on an int type, which causes the error. Writing a.append(…) is fine because a is a list, but as soon as you index into the list, you’re dealing with with the numbers within the list, and they … Read more
How to make a set of lists
You can create a set of tuples, a set of lists will not be possible because of non hashable elements as you mentioned.
ArrayList vs List<> in C#
Yes, pretty much. List<T> is a generic class. It supports storing values of a specific type without casting to or from object (which would have incurred boxing/unboxing overhead when T is a value type in the ArrayList case). ArrayList simply stores object references. As a generic collection, List<T> implements the generic IEnumerable<T> interface and can be used easily in LINQ (without requiring any Cast or OfType call). ArrayList belongs to the days that C# didn’t have … Read more
What does the “x for x in” syntax mean?
This is just standard Python list comprehension. It’s a different way of writing a longer for loop. You’re looping over all the characters in your string and putting them in the list if the character is a digit. See this for more info on list comprehension.
Python 2: AttributeError: ‘list’ object has no attribute ‘strip’
strip() is a method for strings, you are calling it on a list, hence the error. To do what you want, just do Since, you want the elements to be in a single list (and not a list of lists), you have two options. Create an empty list and append elements to it. Flatten the … Read more
HashSet vs. List performance
A lot of people are saying that once you get to the size where speed is actually a concern that HashSet<T> will always beat List<T>, but that depends on what you are doing. Let’s say you have a List<T> that will only ever have on average 5 items in it. Over a large number of cycles, if a single item … Read more
What’s the difference between lists enclosed by square brackets and parentheses in Python?
Square brackets are lists while parentheses are tuples. A list is mutable, meaning you can change its contents: while tuples are not: The other main difference is that a tuple is hashable, meaning that you can use it as a key to a dictionary, among other things. For example: Note that, as many people have pointed out, you … Read more