How to make a function that returns the positional value of a number?

Question

I need to make a function that returns the value corresponding to its positional value.

Example:

positional value
Ten in 1234 returns 3
hundred in 1234 returns 2
1 unit of thousand, 2 hundred, 3 ten, 4 unit

I'd tried this:

def positional_value(x):
  x=str(x)
  numbers=[]
  numbers.extend(x)
  numbers.reverse()
  for index,i in enumerate(numbers):
    if index==0:
      print(i) #so where x is 1234, Here I can get 4.

With what I tried I just can get the numbers by index. I thought that using a list with the positional values names (unit, ten, hundred, unit of thousand, ...) will help to describe each query to the function.

output example: when you print the function:

1 unit of thousand
2 hundred
3 ten
4 unit
#and goes on when the number is bigger

Could you add an example of what you want the function to print when you pass it `1234`? — Deepstop, Jul 21 '19 at 23:21
If you want a `function that returns the value corresponding to its positional value`, it seems like `positional_value` should take two arguments: the number and the position. — Mark, Jul 21 '19 at 23:22
^ (with the addition of a simple lookup table from strings `'hundereds", "thousands"`, etc. to the corresponding digit indices) — Linuxios, Jul 21 '19 at 23:25
I dind't understand your question at first, sorry I made an update in my answer — developer_hatch, Jul 21 '19 at 23:32

Boris Lipschitz · Accepted Answer · 2019-07-21T23:31:16.370

4

def positional_value(x, pos):
    return x // (10**(pos-1)) % 10


NAMES = ["", "unit", "ten", "hundred", "thousand"]
for pos in range(4,0,-1):
    val = positional_value(1234,pos)
    if val!=0:
        print("%d %s" %(val, NAMES[pos]))

edited Jul 21 '19 at 23:31

answered Jul 21 '19 at 23:25

Boris Lipschitz

1,514
8
12

This will work adding the corresponding word to the `print(positional_value(1234,1))` – Y4RD13 Jul 21 '19 at 23:30
2

Edited to a more complete example. Obviously, you need to know your supported maximum, so you could extend it to have those words. Also, add sanity checks for wrong types, negative numbers, etc. – Boris Lipschitz Jul 21 '19 at 23:31

developer_hatch · Answer 2 · 2019-07-21T23:31:26.287

A way to do it if you want the digits is:

def positional_value(x):
  numbers=[]
  v = x
  while v != 0:
    numbers.append(v%10)
    print(v%10)
    v = v // 10
    print(v)
  return numbers

But if you want the index of a specific number in your big number:

def positional_value(x, n):
  numbers=str(x)
  return numbers.find(str(n)) 

print(positional_value(1234, 2))
1
print(positional_value(1234, 4))
3

But if you want to look it backwards, reverse is ok

def positional_value(x, n):
  numbers=str(x)[::-1]
  return numbers.find(str(n)) 

print(positional_value(1234, 2))
2
print(positional_value(1234, 4))
0

Deepstop · Answer 3 · 2019-07-22T01:01:47.640

3

Similar to accepted answer, but using the value as a string, rather than integer division.

def positional_values(x):
    positions = ['unit', 'ten', 'hundred', 'unit of thousand', 'ten-thousand',
                 'hundred-thousand', 'unit of million', ]
    for i, c in enumerate(str(x)):
        print(f"{int(c)}: {positions[len(str(x)) - i - 1]}")

positional_values(1234)

1: unit of thousand
2: hundred
3: ten
4: unit

edited Jul 22 '19 at 01:01

answered Jul 22 '19 at 00:37

Deepstop

3,627
2
8
21

It's a clean code, just need to be in a function and is perfect! – Y4RD13 Jul 22 '19 at 00:48
OK, updated into a function. – Deepstop Jul 22 '19 at 01:02

How to make a function that returns the positional value of a number?

3 Answers3