Extracting rows based on condition on one column

[Robotguy]

Thanks, it worked!

Out of curiosity, here is a little test I did comparing the execution time. It appears the NumPy method is 75x faster than looping. Do, you know what makes NumPy fast? Does it store the array in some efficient manner or something else?

import time
input = np.arange(4*10**7).reshape((10**7, 4))

# First method: Using NumPy
start_time = time.time()
print(input[(-1000 < input[:, 2]) & (input[:, 2] < 10000)])
print(time.time()-start_time)
start_time = time.time()

# Second method: Without NumPy

diff = []
for row in range(10**7):
    if -1000 < arr[row, 2] < 10000:
          diff.append(arr[row, :])

print(diff)

print(time.time()-start_time)