Python: 将选定的行从列表复制到另一个

Question

我正在尝试编写一个函数，将选定的行从一个列表复制到另一个，基于第三个列表，该列表指出应该采用的点。 “1”-用这个东西复制行，“0”省略。这是我的代码：

stuff = [
[1, 2, 3],
[10, 20, 30],
[100, 200, 300],
[1000, 2000, 3000],
[10000, 20000, 30000],
]

chooseThese = [1,0,1,1,0]

def fnChoose(arr1D, arr):
    new = []
    for digit in arr1D:
        for row in arr:
            if arr1D[digit] == 1:
                new.append(arr[row])
            else:
                continue
    return new


print (fnChoose(chooseThese, stuff))

结果我不想得到：

[[1, 2, 3], [100, 200, 300], [1000, 2000, 3000]]

不幸的是我的功能不起作用，闲置显示以下错误：

Traceback (most recent call last):
  File "~\file.py", line 21, in <module>
    fnChoose(chooseThese, stuff)
  File "~\file.py", line 16, in fnChoose
    new.append(arr[row])
TypeError: list indices must be integers or slices, not list

我应该如何修正这个功能？如何将整行附加到列表？

Answer 1

一种更简单的方法是使用 索引列表 而不是 0/1 列表，以使用 enumerate 创建 索引理解 或使用 zip 的组合列表：

stuff = [
[1, 2, 3],
[10, 20, 30],
[100, 200, 300],
[1000, 2000, 3000],
[10000, 20000, 30000],
]

chooseThese = [1,0,1,1,0]

# use enumerate (two variants)
new = [s for index, s in enumerate(stuff) if chooseThese[index] == 1]
print(new)
new = [stuff[index] for index, choose in enumerate(chooseThese) if choose == 1]
print(new)

# use zip
new = [s for choose, s in zip(chooseThese, stuff) if choose == 1]
print(new)

# use indexed chooser-variable
chooseThese = [0,2,3]
new = [stuff[index] for index in chooseThese]
print(new)

Answer 2

您应该跟踪您要追加的列表的索引。

stuff = [                                                                              
     [1, 2, 3],                                                                    
     [10, 20, 30],                                                                 
     [100, 200, 300],                                                              
     [1000, 2000, 3000],                                                           
     [10000, 20000, 30000],                                                        
     ]                                                                             
chooseThese = [1,0,1,1,0]                                                              

def fnChoose(arr1D, arr):                                                              
    new = []                                                                           
    index = 0                                                                          
    for row in arr:                                                                    
        if (arr1D[index] == 1):                                                        
            new.append(row)                                                            
        index += 1                                                                     
    return new                                                                         

print (fnChoose(chooseThese, stuff))

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