Calculating the number of zero crossings in a list in python

I am trying to find the number of zero crossing in a list. The code I am using is:

for i in range(1, len(value)):
    zerocrossing = 0
    if ((value[i-1]) > 0 and value[i] < 0):
        zerocrossing += 1
    if ((value[i-1]) < 0 and value[i] > 0):
        zerocrossing += 1
stdio.writeln('The Number of Zero Crossings is ' + str(zerocrossing))

This code doesn’t give me any errors, but it’s not giving me the right answer. If I give it the input [1.0, -1.0, 1.0] it gives me 1, but it should give 2. What am I doing wrong?

Answer

You’re setting zerocrossing to zero at every loop iteration. Move zerocrossing = 0 outside the for-loop.