[英]List Comprehension with Multiple Conditions
At the moment I am trying to figure out how to solve a simple problem using List Comprehension. 目前,我正在尝试找出如何使用List Comprehension解决一个简单的问题。 The point is to make a list and fill it with 1 at the beginning and at the end of the list.
关键是要创建一个列表,并在列表的开头和结尾处用1填充。 The rest elements are filled with 0.
其余元素填充为0。
I already tried the following: 我已经尝试了以下方法:
desired_length = int(input('Enter the desired length: '))
list_=[0 if x==0 if x==desired_length-1 else x for x in range(desired_length)]
print(list_)
Edit Fixed the square brackets 编辑固定方括号
And here is the code I am trying to convert: 这是我要转换的代码:
def test():
desired_length = int(input('Enter the desired length: '))
list_ = []
for i in range(desired_length):
if i == 0 or i == desired_length - 1:
list_.append(1)
else:
list_.append(0)
print(list_)
You have 2 very easy ways of achieving the result you want. 您有2种非常简单的方法来获得所需的结果。
You could use the in
operator and since bool
Is a subset of int
Just cast it to int
: 您可以使用
in
运算符,因为bool
是int
的子集,只需将其转换为int
:
list_ = [int(i in (0, desired_length - 1)) for i in range(desired_length)]
Or just using the star operator to unpack a list of zeros of length-2
And put 1
's at each end, no looping required 或者只是使用星操作解压的零的列表
length-2
并把1
的每一端,无需循环
list_ = [1, *([0]*(desired_length-2)), 1]
Firstly a dictionary is defined by {}
and a list by []
you are defining a dictionary not a list. 首先,字典由
{}
定义,列表由[]
定义,您在定义字典而不是列表。
Secondly, this is what you want 其次,这就是你想要的
[1 if (idx==0 or idx == (desired_length-1)) else 0 for idx in range(desired_length)]
what you are doing sets 1 at the start and end but 1,2,3 and so on in between 您正在做的事情在开始和结束处设置了1,但是在其中的1,2,3等
Thirdly, you have the condition set to put 0 at the start and end rather than 1. 第三,您将条件设置为在开始和结束处放置0而不是1。
using list comprehension 使用列表理解
desired_length = int(input('Enter the desired length: '))
list_ = [(1 if i in [0,desired_length-1] else 0) for i in range(desired_length)]
print(list_)
output 产量
Enter the desired length: 10
[1, 0, 0, 0, 0, 0, 0, 0, 0, 1]
Here 这里
desired_length = int(input('Enter the desired length: '))
lst = [1 if idx == 0 or idx == desired_length-1 else 0 for idx,x in enumerate(range(desired_length))]
print(lst)
There is a simple way to do that. 有一个简单的方法可以做到这一点。 Here is my code:
这是我的代码:
def test():
desired_length = int(input('Enter the desired length: '))
list_ = [0]*desired_length
list_[0]=1
list_[-1]=1
I hope I helped! 希望我能帮上忙!
我在这里使用短路表达式而不是三元条件(就像Imtinan Azhar的答案一样 )
[int(idx==0 or idx==desired_length - 1) for idx in range(desired_length)]
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