8. List Comprehension To create a new list by applying an expression to each element of an existing one: # Create a new list with lengths of each element lengths = [len(element) for element in elements] 9. Sorting a List To sort a list in ascending order (in-place): elements.sort(...
嵌套列表推导式可用于展平多维数组，这是数据科学中常见的预处理任务。# list comprehension_list = [x**2 for x in range(1, 11)]# nested list comprehension to flatten listmatrix = [[1, 2, 3], [4, 5, 6], [7, 8, 9]]flat_list = [num # append to list for row in matrix # o...
5、嵌套列表解析 Nested List Comprehensions >>>matrix= [ ... [1, 2, 3, 4], ... [5, 6, 7, 8], ... [9, 10, 11, 12], ... ] The following list comprehension will transpose rows and columns: >>> [[row[i] for row in matrix] for i in range(4)] [[ 1, 5, 9], [...
dict comprehension:{key-expr : value-expr for value in collection if condition} set comprehension:{expr for value in collection if condition} map: 内置函数,用法,返回一个输入序列每个元素经过函数处理后的返回值列表。 Nested list comprehension: list comprehension 中可以使用多个 for loop。 Functions# L...
The initial expression in a Python list comprehension can be another list comprehension. nested_list_comprehension.py #!/usr/bin/python M1 = [[1, 2, 3], [4, 5, 6], [7, 8, 9]] M1_tr = [[row[i] for row in M1] for i in range(3)] ...
Createlistcomprehension: squares squares = [i**2foriinrange(0,10)] nested list comprehensions [[output expression]foriterator variableiniterable] writing a list comprehension within another list comprehension, or nested list comprehensions. # Create a 5 x 5 matrix using a list of lists: matrixma...
Nested List Comprehension We can also use nested loops in list comprehension. Let's write code to compute a multiplication table. multiplication = [[i * jforjinrange(1,6)]foriinrange(2,5)]print(multiplication) Run Code Output [[2, 4, 6, 8, 10], [3, 6, 9, 12, 15], [4, 8...
first_element = nested_list[0][0] # 第一个列表中的第一个元素 second_element = nested_list[1][2] # 第二个列表中的第三个元素 third_list = nested_list[2] # 第三个列表 print(first_element, second_element, third_list) 1. 2. ...
下面是本文中提到的三种创建空的二维列表的方法的关系图。 erDiagram List -->|使用嵌套列表推导式| Nested List Comprehension List -->|使用循环和列表附加| Loop and Append List -->|使用numpy库| numpy Library 以上是本文的内容。希望对你有所帮助!
Learn how to effectively use list comprehension in Python to create lists, to replace (nested) for loops and the map(), filter() and reduce() functions, ...!