python - 值错误: How to iterate through a tuple of Boolean True/False statements?

Question

我有一个 numpy ndarray tup1 语句 True 和 False

print(tup1)

array([[ True, False, False, False],
       [ True, False, False, False],
       [False, False, False, False],
       [ True,  True, False, False]], dtype=bool)

我想通过以下方式迭代这个元组tup1:

for i in tup1:
    if i == True:
        pass
    else:
        do something

这将对所有“False”条目执行一些操作。但是，这不起作用:我收到以下错误:

---------------------------------------------------------------------------
ValueError 
Traceback (most recent call last)
<ipython-input-57-0d2a4ade1205> in <module>()
      1 for i in tup1:
----> 2     if i == True:
      3         pass
      4     else:

ValueError: The truth value of an array with more than one element is ambiguous. Use a.any() or a.all()

Answer 1

你有一个二维数组，所以只需创建一个嵌套的 for 循环，首先迭代每一行，然后迭代值:

for row in tup1:
    for item in row:
        if item: #equivalent to `if item == True`
            pass
        else:
            dosomething()

或简化为:

for row in tup1:
    for item in row:
        if not item: #equivalent to `if item == False`
            dosomething()