Syntax of List Comprehension The syntax oflist comprehensionin Python follows this structure: [expressionforiteminiterableifcondition] expression→ The operation or transformation applied to each item. for item in iterable→ Loops through the given iterable (e.g., list, tuple, range). if condition(...
deftest_for(array): a=[]foriinarray: a.append(i+1)returna dis.dis(test_for)20 BUILD_LIST 03 STORE_FAST 1(a)3 6 SETUP_LOOP 31 (to 40)9LOAD_FAST 0 (array)12GET_ITER>> 13 FOR_ITER 23 (to 39)16 STORE_FAST 2(i)4 19 LOAD_FAST 1(a)22LOAD_ATTR 0 (append)25 LOAD_FAST ...
A list comprehension combines the for loop and the creation of new elements into one line, and automatically appends each new element. squares = [value**2 for value in range(1, 11)] print(squares) To use this syntax, begin with a descriptive name for the list, such as squares. Next o...
The above pseudo code shows the syntax of a list comprehension. It consists of three parts: a for loop, optional conditions, and an expression. A for loop goes through the sequence. For each loop an expression is evaluated if the condition is met. If the value is computed it is appended...
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: ...
With list comprehension you can do all that with only one line of code: Example fruits = ["apple","banana","cherry","kiwi","mango"] newlist = [xforxinfruitsif"a"inx] print(newlist) Try it Yourself » The Syntax newlist = [expressionforiteminiterableifcondition==True] ...
语法：# syntax[iforiiniterableifexpression]例子 1，字符串转换成字符列表：# One waylanguage='Pytho...
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):...
# list comprehension to create new list doubled_numbers = [num * 2 for num in numbers] print(doubled_numbers) Run Code Output [2, 4, 6, 8] Here is how the list comprehension works: Python List Comprehension Syntax of List Comprehension [expression for item in list if condition ==...
4 当然除了计算之外，我们还可以做一些比较特殊的字符串操作，比如：print [m + n for m in 'ABC' for n in 'XYZ']我们可以看到我们把A B C 都加了一遍XYZ 如果要用正常的循环也是可以完成的就是了，这样的操作更加简单便捷。5 之前有一道练习题 列出当前目录下的所有文件名和目录...