# Counting letters in a number between 1 and 1000

• ergospherical
In summary, there are eleven letters in a number between 1 and 1000 inclusive. The algorithm can be more efficient by counting the number of letters in a number and excluding spaces and hyphens.
ergospherical
Excluding spaces and hyphens, how many letters are there in a given number between 1 and 1000 (inclusive)? How can I make my algorithm more efficient?

Python:
dig_lens = [4,3,3,5,4,4,3,5,5,4]
tens_lens = [0,3,6,6,6,5,5,7,6,6]
teens_lens = [0,6,6,8,8,7,7,9,8,8]

def num_letters(n):
nlist = []
while(n>=1):
nlist.append(n%10)
n//=10
length = len(nlist)

if(n==1000):
return 11

count = 0
if(length == 1):
count = count + dig_lens[n]

if(length == 2):
if(nlist[1]==1 and nlist[0]>0):
count = count + teens_lens[nlist[0]]
else:
count = count + tens_lens[nlist[1]] + dig_lens[nlist[0]]

if(length == 3):
count = count + dig_lens[nlist[2]] + 7
if(nlist[1]==0 and nlist[0]>0):
count = count + 3 + dig_lens[nlist[0]]
elif(nlist[1]==1 and nlist[0]>0):
count = 3 + count + teens_lens[nlist[0]]
else:
count = 3 + count + tens_lens[nlist[1]] + dig_lens[nlist[0]]

return count

##e.g.##
print(num_letters(816))

berkeman
Does it ever pronounce "hundred"?

it does pronounce hundred - that's accounted for in the first line of the length=3 case!

Last edited:
OK, I see what you're doing. Hundred is "+7".
Eleven is "6".

ergospherical
If length == 1 then you do not need to test if length == 2 (use elif) Edit: or if you are done then return the answer.

You could use count += instead of count = count + ... but if count is 0 then you don't need to include it in any sums anyway. Edit: you hardly need an intermediate count, if you know the answer just return it.

Edit: use more spaces and use them consistently

Python:
dig_lens = [4, 3, 3, 5, 4, 4, 3, 5, 5, 4]
tens_lens = [0, 3, 6, 6, 6, 5, 5, 7, 6, 6]
teens_lens = [0, 6, 6, 8, 8, 7, 7, 9, 8, 8]def num_letters(n):
nlist = []
while n >= 1:
nlist.append(n % 10)
n //= 10
length = len(nlist)

if n == 1000:
return 11

if length == 1:
return dig_lens[n]

if length == 2:
if nlist[1] == 1 and nlist[0] > 0:
return teens_lens[nlist[0]]
else:
return tens_lens[nlist[1]] + dig_lens[nlist[0]]

if length == 3:
count = dig_lens[nlist[2]] + 7
if nlist[1] == 0 and nlist[0] > 0:
return count + 3 + dig_lens[nlist[0]]
if nlist[1] == 1 and nlist[0] > 0:
return count + 3 + teens_lens[nlist[0]]
else:
return count + 3 + tens_lens[nlist[1]] + dig_lens[nlist[0]]

raise RuntimeError("Can't handle more than 1,000")##e.g.##
print(num_letters(10000))

Last edited:
ergospherical
Notice that the size of the number is an input, which means a user might not cooperate with the constraints. How robust is your program if the input parameter were 1,001? Or 10,000?

See how flexible and universal and bulletproof you can make it.

ergospherical
pbuk said:
Edit: you hardly need an intermediate count, if you know the answer just return it.
Yeah, I started thinking I was going to try and do some clever recursive algorithm, but realized it'd just be easier to split it into cases - but didn't get rid of the intermediate count.

Sorry, I have edited and re-edited my code, bad habit. It is prettier now. Should have just passed it through the Black parser straight off, my typing is a bit haphazard after a Friday night in the pub for the first time in 18 months.

Last edited:
Filip Larsen and sysprog
Comments are good, for those who are trying to review your code.
I had a bunch of false starts before I got a handle on what it was doing.

pbuk
pbuk said:
if n == 1000:
return 11
Looks like that test should use the original value of n to trigger properly?

Filip Larsen said:
Looks like that test should use the original value of n to trigger properly?
whoopsie, yeah that and the length=1 case ought to be before the loop

## 1. How do you count the letters in a number between 1 and 1000?

To count the letters in a number between 1 and 1000, you can use a simple mathematical formula. First, you need to write out the number in words. Then, count the number of letters in each word and add them together. For example, the number 456 would be written as "four hundred fifty-six" and has a total of 18 letters.

## 2. Why is it important to count the letters in a number between 1 and 1000?

Counting the letters in a number between 1 and 1000 can be important in various fields such as linguistics, mathematics, and computer science. It can help analyze patterns and relationships between numbers and their corresponding words, or assist in creating algorithms and data structures for processing large numbers.

## 3. Is there a difference in counting letters in numbers written in different languages?

Yes, there can be a difference in counting letters in numbers written in different languages. Some languages may have longer or shorter words for numbers, resulting in a different number of letters. Additionally, languages with different writing systems may have varying rules for counting letters, such as including accents or diacritics.

## 4. Can you use a computer program to count the letters in a number between 1 and 1000?

Yes, you can use a computer program to count the letters in a number between 1 and 1000. There are various online tools and software programs that can quickly and accurately count the letters in a given number. This can be especially helpful when dealing with large numbers or multiple calculations.

## 5. How can counting letters in a number between 1 and 1000 be applied in real life?

Counting letters in a number between 1 and 1000 can be applied in real life in many ways. For example, it can be useful in language studies to analyze word patterns and assist in language learning. It can also be applied in coding and data analysis to efficiently process and manipulate large numbers. Additionally, counting letters in numbers can be used in cryptography and code-breaking to decode hidden messages.

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