Implement C's Switch in Python 3

Sayth Renshaw flebber.crue at gmail.com
Sun Feb 3 01:55:23 EST 2019


On Sunday, 3 February 2019 14:31:14 UTC+11, Avi Gross  wrote:
> Yes, you caught the usual flaw in the often irregular English language.
> 
> The 11th, 12th and 13th do all begin with 1 so there is a simple fix in the
> function version by checking if day//10 is 1.
> 
> Revised example:
> 
> """ Use last digit to determine suffix handling teens well """
> 
> def nthSuffix(day):
>     if (day // 10 == 1):
>         suffix = "th"
>     else:
>         nth = day % 10
>         suffix = "st" if nth == 1 else ("nd" if nth == 2 else ("rd" if nth
> == 3 else "th"))
> 
>     return str(day) + suffix
> 
> >>> [ nthSuffix(day) for day in range(1,32)]
> ['1st', '2nd', '3rd', '4th', '5th', '6th', '7th', '8th', '9th', '10th',
> '11th', '12th', '13th', '14th', '15th', '16th', '17th', '18th', '19th',
> '20th', '21st', '22nd', '23rd', '24th', '25th', '26th', '27th', '28th',
> '29th', '30th', '31st']
> 
> Want a dictionary version? Use the above to make a full dictionary:
> 
> >>> chooseFrom = { day : nthSuffix(day) for day in range(1,32)}
> >>> chooseFrom
> {1: '1st', 2: '2nd', 3: '3rd', 4: '4th', 5: '5th', 6: '6th', 7: '7th', 8:
> '8th', 9: '9th', 10: '10th', 11: '11th', 12: '12th', 13: '13th', 14: '14th',
> 15: '15th', 16: '16th', 17: '17th', 18: '18th', 19: '19th', 20: '20th', 21:
> '21st', 22: '22nd', 23: '23rd', 24: '24th', 25: '25th', 26: '26th', 27:
> '27th', 28: '28th', 29: '29th', 30: '30th', 31: '31st'}
> >>> chooseFrom[1]
> '1st'
> >>> chooseFrom[11]
> '11th'
> >>> chooseFrom[21]
> '21st'
> 


> Subject: Re: Implement C's Switch in Python 3
> 
> On 2019-02-03 02:51, Avi Gross wrote:
> > I may be missing something, but the focus seems to be only on the 
> > rightmost digit. You can get that with
> > 
> I had the same thought, but came across a problem. "11st", "12nd", "13rd"?
> 
> [snip]
> > 
> > Output:
> > 
> >>>> for day in range(1, 32):
> > 	print( nthSuffix(day))
> > 	
> > 1st
> > 2nd
> > 3rd
> > 4th
> > 5th
> > 6th
> > 7th
> > 8th
> > 9th
> > 10th
> > 11st
> > 12nd
> > 13rd
> > 14th
> > 15th
> > 16th
> > 17th
> > 18th
> > 19th
> > 20th
> > 21st
> > 22nd
> > 23rd
> > 24th
> > 25th
> > 26th
> > 27th
> > 28th
> > 29th
> > 30th
> > 31st
> > 
> [snip]
> --

I do like this.

Want a dictionary version? Use the above to make a full dictionary: 

>>> chooseFrom = { day : nthSuffix(day) for day in range(1,32)} 
>>> chooseFrom 
{1: '1st', 2: '2nd', 3: '3rd', 4: '4th', 5: '5th', 6: '6th', 7: '7th', 8: 
'8th', 9: '9th', 10: '10th', 11: '11th', 12: '12th', 13: '13th', 14: '14th', 
15: '15th', 16: '16th', 17: '17th', 18: '18th', 19: '19th', 20: '20th', 21: 
'21st', 22: '22nd', 23: '23rd', 24: '24th', 25: '25th', 26: '26th', 27: 
'27th', 28: '28th', 29: '29th', 30: '30th', 31: '31st'} 
>>> chooseFrom[1] 
'1st' 
>>> chooseFrom[11] 
'11th' 
>>> chooseFrom[21] 
'21st' 

Not having a default case as in switch forced you to write out all possible combinations.

I think the intent and readbility of switch statements is a bit nicer. 

Cheers

Sayth



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