如何在 Python 列表中找到最高量级的 int？

Question

如果列表有正整数和负整数，我如何找到列表中具有最大量级的项目的值？

Answer 1

Late reply, but the other answer and the linked duplicate question seems to have missed an important aspect of your question, namely that you want the value , not the absolute value , with the largest magnitude. In other words, in a list like [-10, 0, 5] , you want the result to be -10 , not 10 .

To get the value with its original sign, you could (conceptually) follow these steps:

1. Get a copy of your list where all values were converted to their absolute values
2. Find the index of the value that has the maximum absolute value
3. Return the value at that index

This can be done quite easily in numpy by using argmax , which returns the index of the maximum value from an array. Step-by-step, it would look like this:

# Create a numpy array from the list you're searching:
xs = np.array([-10, 0, 5])

# Get an array where each value is converted to its absolute value:
xs_abs = np.abs(xs) 
# This gives [10, 0, 5]

# Get the index of the highest absolute value:
max_index = np.argmax(xs_abs) 
# This gives 0

# Get the number from the original array at the max index:
x = xs[max_index] 
# This gives -10

This can be done in a single line like so:

x = xs[np.argmax(np.abs(xs))]

Answer 2

If you mean highest magnitude regardless of negative or positive sign, then you would take the maximum of the list resulting from taking the absolute value of each constituent list value. Does that make sense?

Here is an example:
numbers = [3, 5, 7, -18]

matrix=[]
for x in numbers:
    matrix.append(abs(x))
max(matrix)

Answer 3

this will find the largest value in the list and convert it to positive (afterwards). Useful for normalizations abs(max(xs,key=abs))