What's the Date?

Question

Challenge

Weirdly, this hasn't been done yet: output the current date.

Rules

The date format you should follow is as follows:

YYYY-MM-DD

Where the month and day should be padded by zeroes if they are less than 10.

For example, if the program is run on the 24th May 2017, it should output

2017-05-24

The date can either be always in UTC or in the local date.

You must handle leaps years. i.e. in leap years, February has 29 days but 28 days in a normal year.

Winning

Shortest code in bytes wins.

Answer 1

Bash, 16 7 bytes

-8 bytes thanks to Neil (and fergusq) (no pipe required to output)
-1 byte thanks to 12431234123412341234123 (use the built-in option with flag -I!)

date -I

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Answer 2

PHP, 17 bytes

<?=date('Y-m-d');

Answer 3

Bash, 15 bytes

printf '%(%F)T'

Sample run:

bash-4.4$ printf '%(%F)T'
2017-05-24

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Answer 4

Japt, 6 bytes

Ks3 ¯A

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Explanation:

Ks3 ¯A
K       // New Date()
 s3     // .toISOString()
    ¯A  // .slice(0,10)

Answer 5

JavaScript (ES6), 34 bytes

_=>new Date().toJSON().split`T`[0]

f=

_=>new Date().toJSON().split`T`[0]

console.log(f());

Answer 6

SQLite, 13 characters

select date()

Good boy, SQLite. Other SQL dialects usually need either current_date or date(now()).

Sample run:

bash-4.4$ sqlite3 <<< 'select date()'
2017-05-24

Answer 7

Mathematica, 20 bytes

DateString@"ISODate"

Answer 8

Perl 6,  14  12 bytes

Date.today.say

Try it

now.Date.say

Try it

Answer 9

Excel, 24 bytes

=TEXT(NOW(),"yyy-mm-dd")

Excel will still do a 4-digit year with only 3 y's.

Answer 10

R, 10 bytes

Sys.Date()

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Answer 11

Lua, 18 characters

print(os.date"%F")

Sample run:

bash-4.4$ lua -e 'print(os.date"%F")'
2017-05-24

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Answer 12

Alice, 9 bytes

/oT\
@%;'

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Explanation

I'll leave the exact control flow as an exercise to the reader, but the linearised code that is being run in Ordinal mode is:

%T'T%;o@

And here is what it does:

%   Split an implicit empty string around an implicit empty string. Really doesn't
    do anything at all.
T   Push the current datetime as a string like "2017-05-24T20:53:08.150+00:00"
'T  Push "T".
%   Split the datetime string around the "T", to separate the date from the time.
;   Discard the time.
o   Output the date.
@   Terminate the program.

One way this might be golfable is to reuse the % to terminate the program in Cardinal mode with a division by zero, but the only layout I've come up with is the following:

\;T
\%o'

But here, the % doesn't actually terminate the program, because we push 111 ('o) right beforehand so there's never a division by zero.

In principle it might also be possible to reuse % to get rid of the ;, since trying to split the date around the time will simply discard the time.

Answer 13

VBA, 5 25 bytes

?Date unpredictable, dependent on system short date settings

?Format(Now,"yyyy-mm-dd")

Output:

2017-05-25 

Answer 14

SmileBASIC 3, 29 bytes

SB has a date string built in... but it's in the wrong format! It uses slashes instead of dashes, no good. Plus, being the self-respecting BASIC it is, there is no global replace function. I guess I have to do it myself...

D$=DATE$D$[4]="-
D$[7]="-
?D$

Answer 15

Prolog (SWI), 46 bytes

f(X):-get_time(Y),format_time(atom(X),'%F',Y).

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Answer 16

CJam, 22 15 bytes

et3<{sY0e[}%'-*

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-7 bytes thanks to Challenger5.

Explanation:

et                       Get array with [year,month,day,stuff...]
  3<                     Slice array to get [y,m,d] 
    {                    For each item do:
     s                     To string
      Y0e[                 add a 0 to the beginning of the string if it is shorter than 2 chars.
          }%             End for each
            '-*          Join the array with "-" as a separator

Answer 17

Crystal, 30 bytes 24 bytes 21 bytes

-6 thanks to Nick Clifford

-3 from looking at snail_'s answer in Ruby

p Time.now.to_s("%F")

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Answer 18

QBIC, 33 bytes

B=_D?_sB,-4|+@-`+_sB,2|+A+_sB,4,2

Explanation:

B=_D        Assign the system's date to B$
            This is in American mm-dd-yyyy format, so we'll need to do some reformatting
?_sB,-4|    PRINT substring B, take 4 chars from the right
 +@-`         plus the string literal "-", now A$
 +_sB,2|      plus the leftmost two chars
 +A           and A$ again
 +_sB,4,2     plus the middle part.

Answer 19

Python 2,  53  40 bytes

-10 bytes thanks to Gábor Fekete (ISO-8601 is the default format for a date object)

from datetime import*
print date.today()

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How?

datetime.date.today() will return a datetime.date object containing the local date information.

print will print a string representation of that object, this will call the object's __str__ function.

From the docs:

• date.__str__(): For a date d, str(d) is equivalent to d.isoformat().

• date.isoformat(): Return a string representing the date in ISO 8601 format, ‘YYYY-MM-DD’. For example, date(2002, 12, 4).isoformat() == '2002-12-04'.

Answer 20

Go, 62 56 bytes

import."time"
func f()string{return Now().String()[:10]}

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Answer 21

q/kdb+, 18 16 bytes

Solution:

ssr[.z.d$:].".-"

Example:

q)ssr[.z.d$:].".-"
"2018-01-01"

Explanation:

Take the string representation of today's date, and replace the dots with dashes.

ssr[string .z.d;".";"-"] / fully ungolfed solution
ssr[string .z.d;;].".-"  / partially ungolfed solution
           .z.d          / current UTC date (2018.01.01)
    string               / convert to string ("2018.01.01")
ssr[           ;;]       / string-search-replace 
                  .".-"  / the two parameters

Answer 22

Python 2, 40 bytes

from datetime import*;print date.today()

Answer 23

Powershell, 26 17 bytes

Date -f yyy-MM-dd

Thanks to @ConnorLSW for the 9 bytes.

Answer 24

Oracle SQL, 46 bytes

SELECT TO_CHAR(SYSDATE,'YYYY-MM-DD') FROM DUAL

Answer 25

05AB1E, 16 13 bytes

Saved 3 bytes thanks to Kevin Cruijssen

žgžfže)T‰J'-ý

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Explanation

žgžfže)         # push [year, month, day]
       T‰       # divmod each by 10
         J      # join each div and mod result together
          '-ý   # join year-month-day on "-"

Answer 26

C#, 46 45 bytes

_=>System.DateTime.Now.ToString("yyy-MM-dd");

Saved a byte thanks to @raznagul.

Answer 27

Java 8, 26 32 bytes

()->java.time.LocalDate.now()+""

Fixed format thanks to Kevin Cruijssen

Answer 28

Ruby, 23 bytes

Prints the local time.

p Time.now.strftime'%F'

Answer 29

MATLAB/Octave, 25 15 bytes

datestr(now,29)

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---

The built-in function now returns the current system date in a weirdy MATLAB serial format.

datestr formats the weirdy serial format into a string of a requested format - which is in this case 'YYYY-mm-dd'. It turns out that MATLAB has a list of predefined formats for datestr. ISO8601 is one of them and is represented by the number 29, which allows a saving of 10 bytes.

Answer 30

Rust, 84 Bytes

extern crate chrono;fn main(){print!("{}",chrono::Local::now().format("%Y-%m-%d"));}

Answer 31

C++14, 143 bytes 139 bytes

#include <cstdio>
#include <time.h>
int main (){time_t t;char D[11];time(&t);strftime(D,sizeof D,"%Y-%m-%d",localtime(&t));printf("%s",D);}

Timtech pointed out to me that i don't need all spaces

Test me!

Answer 32

Swift, 13 bytes

print(Date())

Answer 33

J, 16 bytes

6!:0'YYYY-MM-DD'

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Answer 34

IBM PC DOS, 8088 Assembly, 55 53 bytes

B4 2A       MOV  AH, 2AH        ; get system date: CX=year, DH=month, DL=day 
CD 21       INT  21H            ; call DOS API
91          XCHG AX, CX         ; move year in CX to AX (dividend) 
B3 64       MOV  BL, 100        ; divide by 100 to separate first two and last two digits of year 
F6 F3       DIV  BL             ; AL = quotient (first two), AH = remainder (last two) 
8B C8       MOV  CX, AX         ; save AX to CX to display last two digits later 
E8 0123     CALL DISP_WORD      ; display binary value in AL 
8A C5       MOV  AL, CH         ; move last two digits to AL 
E8 0123     CALL DISP_WORD      ; display binary value in AL 
B8 0E2D     MOV  AX, 0E2DH      ; display separator and BIOS function 
50          PUSH AX             ; save for next time 
CD 10       INT  10H            ; call BIOS 
8A C6       MOV  AL, DH         ; move month in DH into AL for display 
E8 0123     CALL DISP_WORD      ; display binary value in AL 
58          POP  AX             ; restore separator and BIOS function 
CD 10       INT  10H            ; call BIOS 
8A C2       MOV  AL, DL         ; move day into AL, and fall through PROC for display 
        DISP_WORD PROC
D4 0A       AAM                 ; convert binary to BCD 
05 3030     ADD  AX, '00'       ; convert BCD to ASCII char 
50          PUSH AX             ; save second digit for display later 
86 C4       XCHG AL, AH         ; convert endian, AL = first digit, AH = second digit 
B4 0E       MOV  AH, 0EH        ; PC BIOS display char function 
CD 10       INT  10H            ; call BIOS 
58          POP  AX             ; restore digits
B4 0E       MOV  AH, 0EH        ; PC BIOS display char function 
CD 10       INT  10H            ; call BIOS 
C3          RET                 ; PROC return / return to DOS    
        DISP_WORD ENDP

Output

A complete DOS program, run from the command line outputs current date to the screen.

This ended up being larger than I anticipated. The vast majority of this program is doing what ASM programmers hate doing most which is writing code to convert binary values to ASCII. For this one, I'm using (abusing) built-in binary-to-BCD instructions (AAM in this case) to create a printable ASCII version of the output.

Download and test PRDATE.COM.

Answer 35

Python 2, 59 bytes

Oddly enough, I can't find an easier built-in... somebody else found it. ><

from datetime import*
print datetime.now().isoformat()[:10]

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Answer 36

Fourier, 33 bytes

|~D<10{1}{0o}Do|F5do`-`4d^F`-`3dF

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Uses a function which adds the leading zero... So long :P

Answer 37

jq, 19 characters

(15 characters code + 4 characters command line options)

now|todate[:10]

Sample run:

bash-4.4$ jq -nr 'now|todate[:10]'
2017-05-24

Try in jq‣play

Answer 38

C, 104 79 61 bytes

^{Saved 18 bytes thanks to hvd.}

n,b[99];f(){time(&n);strftime(b,99,"%F",gmtime(&n));puts(b);}

Answer 39

SAS, 31 bytes

%put %sysfunc(date(),yymmdd10.);

Answer 40

MATL, 6 bytes

Z'29XO

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Explanation

Z'    % Push current date and time as a float
29    % Push 29
XO    % String representation of date and time with specified format.
      % Format 29 corresponds to 'yyyy-mm-dd'. Implicitly display

Answer 41

C#, 51 bytes

Console.Write(DateTime.Now.ToString("yyyy-MM-dd"));

Answer 42

Pyth, 20 bytes

j\-+.d3m.[\02`.d+4d2

Try it here.

Answer 43

VBA, 26 Bytes

Anonymous VBE Immediate window function that outputs the current date in the specified format, regardless of system settings, to the VBE immediate window

?Format(Now,"YYYY-MM-DD")

Answer 44

Objective-C, 27 bytes

NSLog(@"%@",[NSDate date]);

Answer 45

Windows batch, 166 144 136 107 bytes

@set X=
@for /f "skip=1" %%x in ('wmic os get localdatetime')do @set X=%%x
@echo %X:~0,4%-%X:~4,2%-%X:~6,2%

Outputs local time

Answer 46

PowerShell, 16 bytes

date -u %Y-%m-%d

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Answer 47

Noether, 8 bytes

6D0 10SP

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Explanation:

6  - Push the number 6 onto the stack
D  - Pop the mode number off the top of the stack and push the ISO date string (Mode 6)
0  - Push the number 0 onto the stack
10 - Push the number 10 onto the stack
S  - Pop the three items, A, B and C off the top of the stack and slice the string, A, from B to C
P  - Print the item on the top of the stack

---

Alternatively, you could use the following method (also for 8 bytes):

6D"T"^#P

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Explanation:

6   - Push 6 onto the stack
D   - Pop the mode number off the top of the stack and push the ISO date string (Mode 6)
"T" - Push the string "T" onto the stack
^   - Pop two strings A and B off the stack and split A by B
#   - Pop the top item off the stack
P   - Print the item on the top of the stack

Answer 48

Haskell, 55 bytes

import Data.Time
m=getCurrentTime>>=putStr.take 10.show

Not exactly the shortest answer (even the Java answer is shorter!)

Explanation

import Data.Time                            --put the function getCurrentTime into scope
m=getCurrentTime>>=putStr.take 10.show
m=                                          --define a variable/function m
  getCurrentTime                            --get the current time wrapped in the IO type
                >>=                         --feed the current time into the following function
                                  show      --display the time as a string
                          take 10.          --take the first ten characters of that to get the date
                   putStr.                  --print it

Answer 49

Python, 39 bytes

Beats this answer by 1 byte.

from datetime import*;str(date.today())

This won't actually work when put in a file and executed, but it does work when you paste this in a python shell. However, it works if you have this in a file and then call that file's __main__ function, so I don't know if this is allowed by the rules. I'm going to assume that it is.

Answer 50

APL (Dyalog), 17 bytes

'-'@5 8⍕1E3⊥3↑⎕TS

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⎕TS Y M D h m s ms

3↑ take the first three

1E3⊥ evaluate in base-1000

⍕ make into string

'-'@5 8 substitute a dash at positions five and eight

Answer 51

Common Lisp, 86 chars

(multiple-value-bind(a b c d e f)(get-decoded-time)(format t"~4a-~2,'0d-~2,'0d"f e d))

Good old verbose Common Lisp!

Try it online!

Answer 52

Funky, 18 bytes

@os.date"%Y-%m-%d"

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Answer 53

vim, 18

i®=strftime("%F")↵

where ® and ↵ are Ctrl-R and Enter.

Answer 54

AWK, 17 bytes

$0=strftime("%F")

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Answer 55

jamal, 32 characters

{@format date=YEAR-0M-0D}{@date}

(Only interesting part is jamal's unusual date format specifiers. For example YYYY would mean YY twice, where YY is the year as in Perl, since 1900.)

Sample run:

bash-4.4$ jamal.pl date.jam 
2018-03-19

Answer 56

Gema, 40 characters

\A=@subst{*\\/*\\/*=\$3-\*-\*;@date}@end

Sample run:

bash-4.4$ gema '\A=@subst{*\\/*\\/*=\$3-\*-\*;@date}@end'
2018-03-19

Answer 57

Zsh, 15 bytes

Who needs date?

print -P %D{%F}

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If we assume the program will only be run in current century, we can save 2 bytes:

print -P 20%D

Answer 58

Japt, 5 bytes

AîKs3

Try it

A         :10
 î        :Slice the following to that length
  K       :  Current date & time
   s3     :  Convert to ISO string

Answer 59

Forth (gforth), 52 bytes

: x 0 <# # # #> ." -"type ; : f time&date 1 .r x x ;

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Code Explanation

\ x prints a dash followed by a 2-digit number with leading zeros
: x               \ start a new word definition
  0 <# # # #>     \ convert number to double-precision, then converts to a string with leading 0
  ." -"type       \ print "-" followed by the string from the previous command
;                 \ end the word definition

: f               \ start a new word definition
  time&date       \ forth built-in to get the components of a date/time (year on top)
  1 .r            \ print the year (with no space appended)
  x               \ print a dash, followed by the month
  x               \ print a dash, followed by the day
;                 \ end word definition

Answer 60

Perl 6, 12 bytes

say now.Date

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Answer 61

Pyth, 19 bytes

++++.d3"-".d4"-".d5

In Pyth . allows you to access a number of extra syntactic goodies. d contains various date options which are accessed with .d#, where # is a number 0-9. 3 is for the current year, 4 is the current month, and 5 is for the current day.

Format for the challenge wants dashes between each element of the date so we append them. Pyth using Polish notation for all math operands, thus the ++++.