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1. Top results related to create a list in python

   • Create a list of multiple URLs in Python from a list in CSV

     Top Answer

     Answered Jul 27, 2018 · 1 votes

     To read a .csv, I use this:

     result = []for line in open("file.csv"): result.append(line.split(','))-

     This will give you a list of each element between the commas. I don't know which of the se elements you need, but take a look at result[0] to see which index you need.

     With the index you need,

     fmtstr = "https://www.ncbi.nlm.nih.gov/nuccore/{}?report=fasta"urls = []for lst in result: urls.append(fmtstr.format( lst[desired_index] ))-

     Then, you can iterate through the list of urls and use the requests library as you desire.

     This isn't the most compact way of doing things, but it's functional and separates steps for simpler viewing.

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     1/5

   • Create a list from another list in Python, where [i] in list2 = is a counter of list1

     Top Answer

     Answered Sep 09, 2023 · 3 votes

     list2 appears to be a running sum of list1. Use a variable that you add to for each element in list1, and append that to list2 each time through the loop.

     running_sum = 0list1 = [1654, 2175, 2478, 2132, 2250, 2304, 2258, 2111, 1683, 2036, 2089, 1743, 1920, 1854, 2251, 1505, 1698, 1126, 1695, 1590]list2 = []for i in list1: running_sum += i list2.append(running_sum)print(list2)

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     2/5

   • Create a list in Python containing data from specified columns in a csvfile

     Top Answer

     Answered Sep 20, 2017 · 1 votes

     If you are open to pandas you can use this code to filter out desired columns:

     import pandas as pd-df = pd.read_csv('your_file.csv', encoding='utf-8-sig')wantedColumnsList = ["Column2", "Column5", "Column9"]-df = df[wantedColumnsList]

     And if you want to dump it to csv afterwards just use:

     df.to_csv('your_new_file.csv', encoding='utf-8-sig')-

     EDIT: And to find columns with nan:

     df.columns[df.isnull().any()].tolist()-

     To find specific rows with nan:

     df[df.isnull().any(axis=1)]-

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     3/5

   • create a list of all the subsets of a given list in python 3.x

     Top Answer

     Answered Mar 25, 2017 · 9 votes

     You can use itertools.combinations

     to get the combinations:

     >>> import itertools>>> xs = [1, 2, 3]->>> itertools.combinations(xs, 2) # returns an iterator<itertools.combinations object at 0x7f88f838ff48>>>> list(itertools.combinations(xs, 2)) # yields 2-length subsequences[(1, 2), (1, 3), (2, 3)]>>> for i in range(0, len(xs) + 1): # to get all lengths: 0 to 3... for subset in itertools.combinations(xs, i):... print(list(subset))... [][1][2][3][1, 2][1, 3][2, 3][1, 2, 3]

     combining with list comprehension, you will get what you want:

     >>> [list(subset) for i in range(0, len(xs) + 1) for subset in itertools.combinations(xs, i)][[], [1], [2], [3], [1, 2], [1, 3], [2, 3], [1, 2, 3]]-

     Check all answers on Stack Overflow

     4/5

   • Also try

     how do you create a list in python	how to create a list in python w3schools
     how to create a list in python using for loop	how to create a list in python using input
     syntax to create a list in python	how to create a list in python dynamic
     how to create a list in python from a file	how to create a list in python 3

     5/5

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2. www.geeksforgeeks.org › python-listsPython Lists - GeeksforGeeks

   www.geeksforgeeks.org › python-lists

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   Apr 9, 2024 · Learn how to create, access, modify and use lists in Python, a sequence data type that can contain different data types. See examples, methods, complexities and input/output of lists.

3. www.w3schools.com › python › python_listsPython Lists - W3Schools

   www.w3schools.com › python › python_lists

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   Learn how to create a list in Python using square brackets, and how to access, modify, and delete list items. Lists are one of the four built-in data types in Python, and they allow duplicate values and order.

   Code sample

   # Using the list() constructor to make a List

   thislist = list(("apple", "banana", "cherry")) # note the double round-brackets

   print(thislist)

   See more on w3schools

4. www.programiz.com › python-programming › listPython List (With Examples) - Programiz

   www.programiz.com › python-programming › list

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   • Create a Python List. We create a list by placing elements inside square brackets [], separated by commas. For example, # a list of three elements ages = [19, 26, 29] print(ages) # Output: [19, 26, 29]
   • Access List Elements. Each element in a list is associated with a number, known as a list index. The index always starts from 0, meaning the first element of a list is at index 0, the second element is at index 1, and so on.
   • Add Elements to a Python List. We use the append() method to add elements to the end of a Python list. For example, fruits = ['apple', 'banana', 'orange'] print('Original List:', fruits)
   • Change List Items. We can change the items of a list by assigning new values using the = operator. For example, colors = ['Red', 'Black', 'Green'] print('Original List:', colors)

5. python.land › python-data-types › python-listPython List: How To Create, Sort, Append, Remove, And More

   python.land › python-data-types › python-list

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   Jun 5, 2022 · Learn how to create, modify, and use Python lists, one of the most versatile data structures. See examples of how to access, add, remove, sort, slice, and loop over list elements.

6. realpython.com › python-listPython's list Data Type: A Deep Dive With Examples

   realpython.com › python-list

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   Jul 19, 2023 · Learn how to create, access, modify, and manipulate lists in Python, a flexible and versatile built-in data type. This tutorial covers the key features, operations, and use cases of lists with code examples and exercises.

7. www.freecodecamp.org › news › how-to-use-lists-in-pythonHow to Use Lists in Python – Explained with Example Code

   www.freecodecamp.org › news › how-to-use-lists-in-python

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   Mar 1, 2024 · Learn how to create, access, modify, and manipulate lists in Python, a versatile and powerful data structure. See examples, syntax, and advanced concepts with code and explanations.

8. People also ask

   How to create a list in Python?

   • Python has many useful list methods that make it really easy to work with lists. List Comprehension is a concise and elegant way to create a list. For example, print(numbers) # Output: [1, 4, 9, 16, 25] To learn more, visit Python List Comprehension. We use the in keyword to check if an item exists in the list.

   Python List (With Examples) - Programiz

   www.programiz.com/python-programming/list

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   How to create an empty list in Python?

   • Then you define numbers as an empty list. Inside the for loop, you get and print your list object’s size in bytes. The first iteration shows that the size of your empty list is 56 bytes, which is the baseline size of every list in Python. Next, the .append() method adds a new value to your list. Note how the size of numbers grows to 88 bytes.

   Python's list Data Type: A Deep Dive With Examples

   realpython.com/python-list/

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   What is a list data type in Python?

   • Free Bonus: Click here to download the sample code that will make you an expert on Python’s list data type. Python’s list is a flexible, versatile, powerful, and popular built-in data type. It allows you to create variable-length and mutable sequences of objects. In a list, you can store objects of any type.

   Python's list Data Type: A Deep Dive With Examples

   realpython.com/python-list/

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   What is a list in Python?

   • Lists are used to store multiple items in a single variable. Lists are one of 4 built-in data types in Python used to store collections of data, the other 3 are Tuple, Set, and Dictionary, all with different qualities and usage. Lists are created using square brackets: Create a List: List items are ordered, changeable, and allow duplicate values.

   Python Lists - W3Schools

   www.w3schools.com/python/python_lists.asp

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9. pythonbasics.org › listPython Lists (With Examples) - Python Tutorial

   pythonbasics.org › list

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   1. list = [] Lists can hold both numbers and text. Regardless of contents, they are accessed in the same fashion. To access a list add the id between the brackets, such as list[0], list[1] and so on. Define list. An empty list was defined above. Lists can contain all kinds of data. You can create numeric lists like this: