Create an array of repeating elements that increase by 0.1 intervals

Question

What I want my code to do is to create an array of elements: [13.8, 13.9, 14.,...] That increase by 0.1, but each of the elements should repeat 17 times before going on to the next number. Below is my code.

from numpy import*
from pylab import*
def f(elem):
return repeat((elem + 0.1),17)
print f(13.8)

def lst(init):
   yield init
   while True:
       next = f(init)
       yield next
       init = next

for i in lst(13.8):
    print i
    if i > 20:
        break

The output of code only shows an array 13.9 repeating 17 times, but then it shows error:

Traceback (most recent call last):
  File "repeatelementsarray.py", line 19
    if i > 20:
ValueError: The truth value of an array with more than one element is ambiguous. Use a.any() or a.all()

It seems the program is trying to create more than one array of numbers, I just want one array. Also since lst is a generator it shouldn't give an array, so using fromiter?

Answer 1

You can use a combination of np.arange to get the linearly increasing sequence, and np.repeat to repeat each element:

import numpy as np

elems = np.arange(0, 1, 0.1)
reps = np.repeat(elems, 3)

print(reps)
# [ 0.   0.   0.   0.1  0.1  0.1  0.2  0.2  0.2  0.3  0.3  0.3  0.4  0.4  0.4
#   0.5  0.5  0.5  0.6  0.6  0.6  0.7  0.7  0.7  0.8  0.8  0.8  0.9  0.9  0.9]