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问题 I was checking the documentation of list.index() method in python, what I saw is : >>> help(list().index) Help on built-in function index: index(value, start=0, stop=9223372036854775807, /) method of builtins.list instance Return first index of value. Raises ValueError if the value is not present. When I ran the code below gave me some error. >>> l=[1,2,3,43,45,5,6,6] >>> l.index(43,start=1) Traceback (most recent call last): File "<stdin>", line 1, in <module> TypeError: index() takes no

问题 I was checking the documentation of list.index() method in python, what I saw is : >>> help(list().index) Help on built-in function index: index(value, start=0, stop=9223372036854775807, /) method of builtins.list instance Return first index of value. Raises ValueError if the value is not present. When I ran the code below gave me some error. >>> l=[1,2,3,43,45,5,6,6] >>> l.index(43,start=1) Traceback (most recent call last): File "<stdin>", line 1, in <module> TypeError: index() takes no

问题 I'm scraping a website that has a table of satellite values (https://planet4589.org/space/gcat/data/cat/satcat.html). Because every entry is only separated by whitespace, I need a way to split the string of data entries into an array. However, the .split() function does not suit my needs, because some of the data entries have spaces (e.g. Able 3 ), I can't just split everything separated by whitespace. It get's trickier, however. In some cases where no data is available, a dash ("-") is used.

问题 Since Tuples are non-mutable data types in Python and Tuple comprehensions aren't a thing then why do List comprehensions with circle brackets instead of square brackets work fine and produce regular Tuples? I thought circular brackets were used to define Tuples not Lists (I know I'm not wrong there). From my understanding I'm appending values to a Tuple that has already been defined and I'm able to update a Tuple and that's not supposed to happen (in Python) as Tuples are non-mutable. I'm

问题 Since Tuples are non-mutable data types in Python and Tuple comprehensions aren't a thing then why do List comprehensions with circle brackets instead of square brackets work fine and produce regular Tuples? I thought circular brackets were used to define Tuples not Lists (I know I'm not wrong there). From my understanding I'm appending values to a Tuple that has already been defined and I'm able to update a Tuple and that's not supposed to happen (in Python) as Tuples are non-mutable. I'm

问题 I'm fairly new to programming; I've only been studying Python for a few weeks. I've been given an exercise recently that asks me to generate a list of integers, and then manually sort the numbers from lowest to highest in a separate list. import random unordered = list(range(10)) ordered = [] lowest = 0 i = 0 random.shuffle(unordered) lowest = unordered[0] while i in unordered: if unordered[i] < lowest: lowest = unordered[i] i += 1 if i >= len(unordered): i = 0 ordered.append(lowest)

问题 I'm fairly new to programming; I've only been studying Python for a few weeks. I've been given an exercise recently that asks me to generate a list of integers, and then manually sort the numbers from lowest to highest in a separate list. import random unordered = list(range(10)) ordered = [] lowest = 0 i = 0 random.shuffle(unordered) lowest = unordered[0] while i in unordered: if unordered[i] < lowest: lowest = unordered[i] i += 1 if i >= len(unordered): i = 0 ordered.append(lowest)

问题 So I'm using a nested list to store some data and I'm having trouble with changing specific values of one of the sublists: if attributes[3] == 'W': self.board[3][3] = 'W' (numbers are placeholders i'm using to test) board is a class variable that is created as follows (I'm trying to create a grid as specified by a user, with their input for column and row sizes making up the first two parts of attributes) self.board = [] rows = [] self.score = [0, 0] for x in range(attributes[0]): rows.append

问题 I want to create a list of variations of applying a function to every element of a list. Here is a quick example of what I mean. applyVar f [a, b, c] >> [[(f a), b, c], [a, (f b), c], [a, b, (f c)]] Essentially It applies a function to each element of a list individually and stores each possible application in an array. I'm not too sure how to approach a problem like this without using indexes as I have heard they are not very efficient. This is assuming that the function f returns the same

问题 I know that the answer to "how to change names in a list of data frames" has been answered multiple times. However, I'm stuck trying to generate a function that can take any list as an argument and change all of the column names of all of the data frames in the list. I am working with a large number of .csv files, all of which will have the same 3 column names. I'm importing the files in groups as follows: # Get a group of drying data data files, remove 1st column files <- list.files('Mang