Problem 47. Extract leading non-zero digit

Benford's Law states that the distribution of leading digits is not random. This is probably because many things grow logarithmically. Extract the leading digit from these vectors.

• 10 --> 1
• 13 --> 1
• 0.3 --> 3
• -4 --> 4
• -5 --> 5
• -0.006 --> 6

Input will be a vector

 x = [1 0.3 -2 0.001 -0.0006, 582398, 3020];

Output should be

 y = [1 3 2 1 6 5 3];