Input a number and return day of week

Question

Not restricted to any one programming language.

What I'm saying is you pass 1 to it and it returns Monday, 7 corresponds with sunday and so on.

I've managed a 146 byte statement in Java to do the same.

return (n<1?"invalid":(n<2?"monday":(n<3?"tuesday":(n<4?"wednesday":(n<5?"thursday":(n<6?"friday":(n<7?"saturday":(n<8?"sunday":"invalid"))))))));

Your program should:

• output full words (STDOUT)
• not crash if the input is less than 1 or greater than 7

Answer 1

Bash: 47 bytes

Still no bash entry? I'm disappointed ...

case $1 in
    [1-7]) date -d "14-08-1$1" +%A
esac

It uses the days of the current week and simply substitutes the last digit (11-17 August 2014 -- 11 is Monday, 12 is Tuesday, etc.).

Answer 2

Ruby, 69 or 38 bytes

Here is a simple way to improve your code (written in Ruby but it works similarly in Java):

n>0&&n<8?%w{Mon Tues Wednes Thurs Fri Satur Sun}[n-1]+"day":"Invalid"

• Combine the two invalid checks into one.
• Put all the days in an array and use n as an index.
• Factor out the common day.

You can make it even shorter if you import the names of the days of the week from a library, like Ruby's:

n>0&&n<8?Date::DAYNAMES[n%7]:"Invalid"

Note that now I don't decrement n but instead take it modulo 7 to map 7 to 0. This is because DAYNAMES starts with Sunday.

Answer 3

Marbelous 192 191 185 181

}0
=1=2=3=4=5=6=7--
&1&2&3&4&5&6&7{0
&8////////////
4D6F6E547565735765646E65735468757273467269536174757253756E646179
&1&1&1&2&2&2&2&3&3&3&3&3&3&4&4&4&4&4&5&5&5&6&6&6&6&6&7&7&7&8&8&8

Non-zero exit code if the input is invalid

Usage:

# marbelous.py -r day-of-week.mbl 2
Tuesday

Answer 4

Javascript, 95 88 bytes

x=prompt();alert("Invalid 0Mon0Tue0Wednes0Thurs0Fri0Satur0Sun".split(0)[x&~7?0:x]+"day")

7 in binary is 0111, meaning that you can shave off a few characters with a bitwise operation instead of x>0&&x<8.

Edit: Removed the s array with the help of edc65.

Answer 5

C# - 26 Bytes

Expects the day to be stored inside n.
Does not crash, as expected.
Powered by LINQPad™

((DayOfWeek)(n%7)).Dump();

_{Special thanks to bmarks and Stephan Schinkel for byte saving and rule bending, respectively}

Answer 6

C#, 95 bytes

In C# you can do something like this:

return(i>7||i<0)?"invalid":new[]{"mon","tues","wednes","thurs","fri","satur","sun"}[i-1]+"day";

Answer 7

Extended BrainFuck: 104

{a))<(->>}+>,49-(-(-(-(-(-((-)<->>|"sun")<(->>|"satur"&a|"fri"&a|"thurs"&a|"wednes"&a|"tues"&a|"mon")|"day"

Ungolfed (Idiomatic)

{main 
  :flag +
  :input
 
  $input &read_number -
  (-
   (-
    (-
     (-
      (-
       (        $input &reset  ; 7-9
                $flag  &reset
                |"sun" &reset )
                
        $flag ( &reset         ; 6 
                |"satur" &reset  ))
                
       $flag (  &reset         ; 5
                |"fri" &reset    ))
                
      $flag (   &reset         ; 4
                |"thurs" &reset  ))
                
     $flag (    &reset         ; 3
                |"wednes" &reset ))
                
    $flag (     &reset         ; 2
                |"tues" &reset   ))
                
   $flag (      &reset         ; 1
                |"mon" &reset    )

   |"day"
}
{reset (-)}
{read_number , 48- }

;; call main
&main

Answer 8

T-SQL 36

SELECT DATENAME(w,@+6)WHERE(6+@)/7=1

Assumes the variable is stored in @. If it is an invalid input (@>7 or @<1), then it doesn't select anything.

Edit: Apparently a date can be a number. Removed 5 characters with that.

Edit 2: Based on the first edit. Since it's an int, I don't have to use DATEADD(); I can use normal addition instead.

Answer 9

Javascript 93 :(

q=prompt();alert(q<8&&q>0?'0mon0tues0wednes0thurs0fri0satur0sun'.split(0)[q]+'day':'invalid')

Answer 10

Lua - 57 bytes

print(n>0 and n<8 and os.date("%A",9e4*(n+3))or"Invalid")

Lua has os.date() in it's standard library, and it has formatting. So you can pass a time (in this case "9e4*(n+3)") and ask to return the "%A" format, which is the names of the days of the week. Also, very useful in Lua is "a and b or c". If a is true (in the code a is "n>0 and n<8") it returns b, if a is false (or nil) it returns c.

Answer 11

Mathematica 19 16 bytes

DayName@{1,1,#}&

As Dr. Rebmu noted, January 1, 1 A.D. is a good place to start. It (presumably) fell on a Monday.

    DayName@{2014, 9, #} &[1]

Monday

Answer 12

Bash - 21 19

Assuming the input is in variable D:

date +%A -d$D"Jan1"

HTML + PHP - 26

Let $d be an input text

<?=date('l',86400*(3+$d));

Timestamp 86400*3 is the first Sunday from the start of UNIX world.

You can test it by executing:

<?php $d=3; ?>
<?=date('l',86400*(3+$d));

Answer 13

Perl, 60 bytes

Something like this:

$x&&qw{Mon Tues Wednes Thurs Fri Satur Sun}[$x-1]."day"||die

If want to return a message instead and you're concerned about negative indexes you can use this one instead (8 more chars):

$x>0&&qw{Mon Tues Wednes Thurs Fri Satur Sun}[$x-1]."day"||"Invalid"

Answer 14

Lua 134 119 115 100 98

q={"mon","tues","wednes","thurs","fri","satur","sun"}print(n<8 and n>0 and q[n].."day"or"invalid")

Basically the same thought MartinButtner had, except about 4.5 4.1 1.7 1.4 times longer. Does assume n is stored as a variable elsewhere.

Answer 15

Python (84)

lambda a:'imtwtfssnouehrauvneduitnadsnrdudladesaraiyasdydyd yda a    ay y    y'[a if 0<a<8 else 0::8]

I suppose it's an interesting sollution. It takes an idea from another answere I read somewhere (can't find it, I do know it was on this site, so if anyone knows feel free to tell me.) The string was generated with the following J program:

,|:>'invalid';'monday';'tuesday';'wednesday';'thursday';'friday';'saturday';'sunday'

Taking some subtle hints from this answer:

lambda a:' mtwtfssouehrauneduitn snr u   es r   s'[a::7]+'day'if 0<a<8 else'invalid'

Answer 16

Bash 74 48 + error message

A different approach since all other answers focus on storing the strings in some form.

read x;((0<x&&x<8))&&date -d2007010$x +%A||echo out of range

Answer 17

Perl, 54

From STDIN to STDOUT, no date functions, no crash.

print((a,Mon,Tues,Wednes,Thurs,Fri,Satur,Sun)[<>].day)

Answer 18

PHP (56 bytes)

$d=1;echo$d>0&&$d<8?date('D',255600+$d*86400):'Invalid';

Answer 19

Clojure - 99 chars

Plain and simple, despite my best (newbie) attempts:

(defn f[x](get{1"monday"2"tuesday"3"wednesday"4"thursday"5"friday"6"saturday"7"sunday"}x"invalid"))

Answer 20

JS: 58

Assuming n is already stored as a variable.

"0Mon0Tues0Wednes0Thurs0Fri0Satur0Sun".split(0)[n%8]+"day"

As an ES6 function (same assumptions): 67

let d=n=>"0Mon0Tues0Wednes0Thurs0Fri0Satur0Sun".split(0)[n%8]+"day"

This will just print "day" for 0 and loops around for n > 7

Answer 21

Rebmu: 21 characters

pcSYSTEM/locale/daysA

To run:

>> rebmu/args {pcSYSTEM/locale/daysA} 1 
== "Monday"

Invalid numbers will return "none".

>> rebmu/args {pcSYSTEM/locale/daysA} 8 
== none

>> rebmu/args {pcSYSTEM/locale/daysA} 0
== none

For those unfamiliar with Rebmu, it uses case transitions to remove the need for spacing--within the limits of what's legally parseable. Rather than using a InitialCapsToBreak it uses CASEtransitionsTObreak, because that allows a different meaning to be ascribed to an initial run of capitals from if the initial initial run is lowercase.

So it is equivalent to the Rebol program pick system/locale/days a. (Rebmu by convention names its script parameter as "a").

Saves one character over system/locale/days/(a) :-)

Answer 22

Haskell - 62

Wraps around; 0 is Sunday, 8 is Monday, and so on.

words"Mon Tues Wednes Thurs Fri Satur Sun"!!(mod(n-1)7)++"day"

If printing to stdout is required (68 bytes, output is in double quotes):

print$words"Mon Tues Wednes Thurs Fri Satur Sun"!!(mod(n-1)7)++"day"

Answer 23

LiveScript - 49

Returns undefinedday if the input is invalid. ;)

<[Mon Tues Wednes Thurs Fri Satur Sun]>[n-1]+\day

If printing to stdout is required (60 bytes):

console.log<[Mon Tues Wednes Thurs Fri Satur Sun]>[n-1]+\day

Answer 24

Befunge-93 (206 208)

This one was fun to write. I'm sure it can be done in a better way, but… it works! =) Can be tried out here.

Would've been even shorter if the # would jump over entire strings rather than just the individual cell.

&1-    v
vv"Mon"># :# !_
> 1-    v
vv"Tues"># :# !_
> 1-      v
vv"Wednes"># :# !_
> 1-     v
vv"Thurs"># :# !_
> 1-   v
vv"Fri"># :# !_
> 1-     v
vv"Satur"># :# !_
> 1-   v
vv"Sun"># :# !_
>>:#,_"yad",,,@

The basic idea behind it: Get the number and keep decrementing it. Everytime we decrement it, the cursor moves to the right, wraps around and is sent one level lower. Once we hit zero, move to the left instead and push the (first part of the) day name. From then on, the cursor will move straight to the bottom where the string is printed and "day" is appended.

You can see how it works by using the "Step" feature in the link to the online interpreter.

Edit: I managed to shave two bytes off by doing >:#,_ instead of >,,,,,,, which is pretter as well.

Answer 25

MATLAB : 33

datestr(3:9,'dddd');ans(1:7==n,:)

MATLAB : 71

{'mon';'tues';'wednes';'thurs';'fri';'satur';'sun'};[ans{1:7==2} 'day']

Haskell : 75

g n=((++"day").last.take(abs n).words)"mon tues wednes thurs fri satur sun"

Haskell : 97

f n=if elem n[1..7]then["mon","tues","wednes","thurs","fri","satur","sun"]!!n++"day"else"invalid"

Python 3.4.1 : 81

'invalid mon tues wednes thurs fri satur sun'.split(' ')[n*(n in range(8))]+'day'

Answer 26

Java 8 - 69 64 chars

Here's an expression in Java 8, including the import. Now improved (thanks to Tomáš Dvořák):

import java.time.*;
return DayOfWeek.of((i>0&i<8)?i:1).name();

Simply prints MONDAY for bogus values of i

Answer 27

Python - 87

I'm not seeing enough love for dict's .get() This one expects a to be the number

dict(enumerate("mon,tues,wednes,thurs,fri,satur,sun".split(","),1)).get(a,"bad ")+"day"

Answer 28

Python, 95 bytes

"%day"%["mon","tues","wednes","thurs","fri","satur","sun"][n-1] if 0<n<8 else "invalid"

Answer 29

Python 2, 84 83 64

Assuming n is already stored as a variable.

import calendar as c;print c.day_name[n-1]if 0<n<8 else'Invalid' 

Answer 30

Cobra - 43

print if(0<n<8,(n%7)to DayOfWeek,'Invalid')