[FIXED] How to count the number of TRUE until a FALSE in numpy array?

Issue

I'm trying to count the number of True values in a numpy.array until a False is reached.

For example, if you have

condition = np.array([True, True, True, False, 
    False, True, False, True, True, False, True])

Then the desired result would be

np.array([3, 2, 1, 0, 0, 1, 0, 2, 1, 0, 1])

Edit:

Numpy first occurrence of value greater than existing value is not what I'm asking because that's asking about the first time a condition is satisfied. I'm asking how many times in a row a condition is satisfied each time it is satisfied. Find first sequence item that matches a criterion also doesn't work because, again, I'm not asking about the first time a sequence satisfied a condition.

Solution

Line by line to explain the calculation

import numpy as np                                                      

condition = np.array([True, True, True, False, False, True, False, True, True, False, True])                       

rvs = condition[::-1]   # Reverse the array order
rvs                                                                     
# array([ True, False,  True,  True, False,  True, False, False,  True,
        True,  True])

cum_rvs = rvs.cumsum()  # Cumulative sum of Trues                                         
cum_at_zero = (~rvs)*cum_rvs   # Cum where rvs is True set to zero                                         

cum_max = np.maximum.accumulate( cum_at_zero ) # Equivalent to cummax( cum_at_zero )
cum_max                                                               
# array([0, 1, 1, 1, 3, 3, 4, 4, 4, 4, 4])
  
result = cum_rvs - cum_max  # Use cum_max to adjust the cum_rvs down                        

result = result[::-1]  # Reverse the result order                                                
result                                                                  
# array([3, 2, 1, 0, 0, 1, 0, 2, 1, 0, 1])

Or in more condensed form:

rvs = condition[::-1]                                                   
cum_rvs = rvs.cumsum()

result = ( cum_rvs - np.maximum.accumulate((~rvs)*cum_rvs ))[::-1]   
            

                  

Answered By - Tls Chris