# Create a list of strings: fellowshipfellowship = ['frodo','samwise','merry','aragorn','legolas','boromir','gimli']# Create list comprehension: new_fellowshipnew_fellowship = [memberformemberinfellowshipiflen(member) >=7]# Print the new listprint(new_fellowship) output: ['samwise','arag...
很多时候我们需要创建一个满足特定要求的新列表,不得不用for循环来创建,而用列表推导式来表达只需要一行代码即可。列表推导式另一个优点是相比于for循环更高效,因为列表推导式在执行时调用的是Python的底层C代码,而for循环则是用Python代码来执行。比如我们需要创建一个包含平方数的列表,用for循环实现方式如下: ...
(一)使用List Comprehension的好处 在了解Python的List Comprehension之前,我们习惯使用for循环创建列表,比如下面的例子: numbers = range(10) my_list=[]fornumberinnumbers: my_list.append(number*number)print(my_list) 可是在Python中,我们有更简洁,可读性更好的方式创建列表,就是List Comprehension: my_list =...
A list comprehension consists of brackets containing an expression followed by a for clause, then zero or more for or if clauses. The result will be a new list resulting from evaluating the expression in the context of the for and if clauses which follow it. ...
Python List Comprehension错误澄清 这是我的密码: subfolders = [ f.path for f in os.scandir(x) if f.is_dir() ] 我试图用另一种形式编写一组等效的代码: subfolders = [] x = "c:\\Users\\my_account\\AppData\\Program\\Cache" for f in os.scandir(x):...
newlist = [] forxinfruits: if"a"inx: newlist.append(x) print(newlist) Try it Yourself » With list comprehension you can do all that with only one line of code: Example fruits = ["apple","banana","cherry","kiwi","mango"] ...
Suppose we have a list of numbers and we desire to create a new list containing the double value of each element in the list. numbers = [1, 2, 3, 4] # list comprehension to create new list doubled_numbers = [num * 2 for num in numbers] print(doubled_numbers) Run Code Output...
Python List Comprehension List comprehension in Python provides a concise way to create lists. It allows generating a new list by applying an expression to each element in an iterable, such as a list, tuple, or range, in a single line of code. This method improves readability and performance...
transform a list filter a list The syntax of a list comprehension was influenced by mathematical notation of sets. The Python syntax was inspired by the Haskell programming language. S = {x² : x in {0 ... 16}} This is a mathematical notation for creating a set of integer values. ...
list comprehension(列表推导式) 在python中,list comprehension(或译为列表推导式)可以很容易的从一个列表生成另外一个列表,从而完成诸如map, filter等的动作,比如: 要把一个字符串数组中的每个字符串都变成大写: names = ["john", "jack", "sean"] ...