Python: Populate Multidimensional Array

Question

I need to populate a two dimensional array with salary grades and steps.

salaryGrades = []
salaryStep = 0
salaryInc = 1000

for x in range (0,10):
    salaryStep+=100000
    salaryGrades.append([salaryStep])
    for x in salaryGrades:
        salaryInc=+1000
        x.append([salaryInc])


print (salaryGrades)

This obviously gives me an incorrect array. I need each array to increment by 10k and each nested array to increment by 1000.

i.e. [ [10000],[11000],[12000],...][20000],[21000][22000],...] ] up to 100k

How do I get this code to work, or is there a better way?

What is your question?

Robᵩ
– Robᵩ

2013-03-05 19:45:05 +00:00
Commented Mar 5, 2013 at 19:45 — Robᵩ
– Robᵩ, Commented Mar 5, 2013 at 19:45

Patricio Molina · Accepted Answer · 2013-03-05 19:51:44Z

3

I'd use a list comprehension:

>>> salaryGrades = [list(range(s, s + 10000, 1000)) for s in range(10000, 100000, 10000)]
>>> salaryGrades
[[10000, 11000, 12000, 13000, 14000, 15000, 16000, 17000, 18000, 19000],
 [20000, 21000, 22000, 23000, 24000, 25000, 26000, 27000, 28000, 29000],
 [30000, 31000, 32000, 33000, 34000, 35000, 36000, 37000, 38000, 39000],
 [40000, 41000, 42000, 43000, 44000, 45000, 46000, 47000, 48000, 49000],
 [50000, 51000, 52000, 53000, 54000, 55000, 56000, 57000, 58000, 59000],
 [60000, 61000, 62000, 63000, 64000, 65000, 66000, 67000, 68000, 69000],
 [70000, 71000, 72000, 73000, 74000, 75000, 76000, 77000, 78000, 79000],
 [80000, 81000, 82000, 83000, 84000, 85000, 86000, 87000, 88000, 89000],
 [90000, 91000, 92000, 93000, 94000, 95000, 96000, 97000, 98000, 99000]]

edited Mar 5, 2013 at 19:51

Patricio Molina

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answered Mar 5, 2013 at 19:41

NPE

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2 Comments

user2112862 Over a year ago

Why yes, yes I do. Granted, this syntax is a bit too short hand for me to comfortably wrap my head around. Anyway to translate it into syntax similar to OP?

user2112862 Over a year ago

That'll do. You are appreciated.

flonk · Accepted Answer · 2013-03-05 20:28:09Z

You could also do this as a numpy-onliner.

import numpy as np

print 1000*np.arange(10,100).reshape((9,10))


[[10000, 11000, 12000, 13000, 14000, 15000, 16000, 17000, 18000, 19000],
 [20000, 21000, 22000, 23000, 24000, 25000, 26000, 27000, 28000, 29000],
 [30000, 31000, 32000, 33000, 34000, 35000, 36000, 37000, 38000, 39000],
 [40000, 41000, 42000, 43000, 44000, 45000, 46000, 47000, 48000, 49000],
 [50000, 51000, 52000, 53000, 54000, 55000, 56000, 57000, 58000, 59000],
 [60000, 61000, 62000, 63000, 64000, 65000, 66000, 67000, 68000, 69000],
 [70000, 71000, 72000, 73000, 74000, 75000, 76000, 77000, 78000, 79000],
 [80000, 81000, 82000, 83000, 84000, 85000, 86000, 87000, 88000, 89000],
 [90000, 91000, 92000, 93000, 94000, 95000, 96000, 97000, 98000, 99000]]

Especially for large arrays this could speed your code, as the looping is then performed by the numpy module, which uses C.

Lance Roberts · Accepted Answer · 2013-03-05 19:48:41Z

0

Modify your code like so:

for y in range (0,8):
  for x in range (0,9):
    salaryGrades[y][x] = (y+1)*10000 + x*1000

answered Mar 5, 2013 at 19:48

Lance Roberts

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