Python - 将浮点数转换为 int 以用作数组索引返回数组的第 0 个元素

Question

I want to create a new array that has some sifted elements from an old array

This is what the array looks like:

print(freqs[0])
print(freqs[1])
print(freqs[2])
print(freqs[3])
print(freqs[4])

>>(-1.356524149576826+0j)
  (-1.5188337718697111-0.0028277787696928914j)
  (-1.537925820349816+0.02545857328595845j)
  (-1.7483732926022144+0.0875845050778933j)
  (-1.8506826888571075+0.16201185108446528j)

when I cast the index "manually" to troubleshoot it all works fine

print(int(0*scaler), freqs[int(0*scaler)])
print(int(1*scaler), freqs[int(1*scaler)])
print(int(2*scaler), freqs[int(2*scaler)])
print(int(3*scaler), freqs[int(3*scaler)])
print(int(4*scaler), freqs[int(4*scaler)])

>>0 (-1.356524149576826+0j)
  0 (-1.356524149576826+0j)
  1 (-1.5188337718697111-0.0028277787696928914j)
  2 (-1.537925820349816+0.02545857328595845j)
  3 (-1.7483732926022144+0.0875845050778933j)

However, once I put this kind of logic in a loop I always get the 0th element. And I doubled checked that my index variable is in fact an int

for i in range(length):
    index = int(i*scaler)

    if index < length:
    
        newfreqs[i] = freqs[index] 
        print(i,index,freqs[index])

>>0 0 (-1.356524149576826+0j)
  1 0 (-1.356524149576826+0j)
  2 1 (-1.356524149576826+0j)
  3 2 (-1.356524149576826+0j)
  4 3 (-1.356524149576826+0j)

I get the exact same behavior if I use math.floor() instead of int(). Oddly round() seems to work fine but it does not produce the correct index value I need. It is only an issue anywhere inside the loop, outside the loop it works as expected.

Here is the entire function

def reindex(freqs, halfSteps):
    scaler = halfStep**(-halfSteps)

    newfreqs = freqs
    length = len(newfreqs)
    
    for i in range(length):
        index = int(i*scaler)
        if index < length:
        
            newfreqs[i] = freqs[index] 
            print(i,index,freqs[index])
        
    return newfreqs

Answer 1

Changed the initialization of newfreq to 'zeros(len(freqs))'