Compare two numbers given as strings

Question

I have a problem at work. I need to compare two numbers that come as strings from two different databases. The numbers may come with leading zeroes and/or leading/trailing spaces. So I may have "0001 " from one database and " 1 " from the other one.

I solved the problem in C# with the following code:

Func<string, string, bool> f = (a,b) => int.Parse(a.Trim()) == int.Parse(b.Trim())

The challenge

This is a really simple challenge, suitable for beginners and any kind of esoteric languages. Given two numbers as strings that may come with leading zeroes and/or leading/trailing spaces, write the shortest code that checks if the two strings represent the same number.

• The inputs need to be two strings or the equivalent in your language (a char array is OK), and they will always represent integer values greater than zero.
• The output must be any two consistent values that represent a truthy value and a falsey value.

Examples

A          B          Result
----------------------------
"0001"     "1    "    true
"1450"     "1450 "    true
"0010001 " " 10001  " true
"0010000"  "  10  "   false
"101023"   "101024"   false

This is code-golf, so may the shortest code for each language win!

Answer 1

Javascript, 11 bytes

a=>b=>+a==b

Abusing Javascript's casting rules a bit; +a coerces a into a numeric type.

-6 bytes thanks to Shaggy and Martin Ender♦

Also a cool take by LiefdeWen:

a=>b=>~~a==~~b

Answer 2

05AB1E, 1 byte

Q

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Explanation

Comparison for equality Q will automatically try to evaluate strings as ints before comparing.

Answer 3

Operation Flashpoint scripting language, 33 bytes

f={call format(["%1==%2"]+_this)}

Call with:

hint format["%1\n%2\n%3\n%4\n%5",
    ["0001", "1    "] call f,
    ["1450", "1450 "] call f,
    ["0010001 ", " 10001  "] call f,
    ["0010000", "  10  "] call f,
    ["101023", "101024"] call f]

Output:

Alternative version (41 bytes):

f={{t=call _x;r=t==s;s=t}forEach _this;r}

Still 5 bytes shorter than the more straightforward f={t=_this;call(t select 0)==call(t select 1)}

39 bytes:

f={{t=call _x;r=t==s;s=t}count _this;r}

count (which returns the size of an array) works instead of forEach, because you can give it a "lambda" that is used as a condition to count only the array elements that meet that condition. The "condition" used in this case is not a valid condition, but it doesn't matter here because it doesn't cause an error and the return value of the count is not needed.

Answer 4

Taxi, 488 bytes

Go to Post Office:w 1 l 1 r 1 l.Pickup a passenger going to The Babelfishery.Pickup a passenger going to The Babelfishery.Go to The Babelfishery:s 1 l 1 r.Pickup a passenger going to Equal's Corner.Pickup a passenger going to Equal's Corner.Go to Equal's Corner:n 1 l 1 l 1 l.Switch to plan "b" if no one is waiting.'1' is waiting at Writer's Depot.[b]'0' is waiting at Writer's Depot.Go to Writer's Depot:n 1 l 1 r.Pickup a passenger going to Post Office.Go to Post Office:n 1 r 2 r 1 l.

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Ungolfed:

Go to Post Office: west 1st left 1st right 1st left.
Pickup a passenger going to The Babelfishery.
Pickup a passenger going to The Babelfishery.
Go to The Babelfishery: south 1st left 1st right.
Pickup a passenger going to Equal's Corner.
Pickup a passenger going to Equal's Corner.
Go to Equal's Corner: north 1st left 1st left 1st left.
Switch to plan "b" if no one is waiting.
'1' is waiting at Writer's Depot.
[b]
'0' is waiting at Writer's Depot.
Go to Writer's Depot: north 1st left 1st right.
Pickup a passenger going to Post Office.
Go to Post Office: north 1st right 2nd right 1st left.

Taxi is (relatively) well-suited to this challenge because strings are the only input or output type allowed. The Babelfishery is what converts strings to number (and vice versa) and it handles stripping all the spaces and leading zeroes. It will also handle negative numbers if the - is immediately before the first digit. After that, Equal's Corner checks the two values against each other and Writer's Depot provides the output in string format. Output is 1 for truthy and 0 for falsey.

Answer 5

C (gcc), 27 bytes

f(s,t){s=atoi(s)==atoi(t);}

With -O0 (which is the default setting).

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C, 32 bytes

f(s,t){return atoi(s)==atoi(t);}

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Answer 6

J, 4 bytes

=&do

Compare = after & evaluating do. Can also be =&". Try it online!

Answer 7

Retina, 11 bytes

.+
$*
D`
¶$

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Input is linefeed separated, but the test suite uses comma separation for convenience. Prints 1 for equality and 0 for inequality.

Explanation

.+
$*

Convert each line to unary. This ignores leading zeros and spaces.

D`

Deduplicate: clear the second line if both are the same.

¶$

Check that the string now ends in a linefeed.

Answer 8

Python 3, 25 bytes

lambda a,b:int(a)==int(b)

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Answer 9

Brain-Flak, 22 bytes

(([{}]{})[{(){}}](){})

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Saved 4 bytes thanks to Jo King.

Answer 10

Triangularity, 17 bytes

..)..
.Ii).
@Ii=.

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Triangularity is, for once, competitive!

How it works

Triangularity requires the code to have a triangular distribution of the dots. That is, the length of each row must be equal the number of rows multiplied by 2 and decremented, and each row must have (on each side) a number of dots equal to its position in the program (the bottom row is row 0, the one above it is row 1 and so forth). Keeping this in mind, let's analyse how the code works:

..).. || Push a 0 onto the stack.
.Ii   || Get the 0th input and cast it to an integer.
   ). || Push another 0 onto the stack.
@I    || Increment the ToS => 1. Get the first input.
  i=. || Then cast it to an integer and compare their equality.

Answer 11

Alice, 7 bytes

X/n
o@i

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Any non-digit separator works. Prints 1 for equality and 0 otherwise.

Explanation

X   XOR, does nothing.
/   Switch to Ordinal mode.
i   Read all input as a string.
/   Switch to Cardinal mode.
X   XOR. Implicitly finds all integers in the string and pushes them separately
    onto the stack. The XOR gives 0 if the values are identical.
n   Logical NOT. Gives 1 for equal inputs and 9 otherwise.
/   Switch to Ordinal.
o   Print the 0 or 1 as a string.
/   Switch to Cardinal.
@   Terminate the program.

Answer 12

Japt, 3 bytes

¥Vn

Try it

Converts the second input to an integer and compares equality with the first.

Answer 13

APL (Dyalog), 4 bytes

3 bytes saved thanks to @Adám

=/⍎¨

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Answer 14

jq, 24 characters

map(tonumber)|.[0]==.[1]

The 2 strings are passed as items of an array.

Sample run:

bash-4.4$ jq 'map(tonumber)|.[0]==.[1]' <<< '["0010001 ", " 10001  "]'
true

bash-4.4$ jq 'map(tonumber)|.[0]==.[1]' <<< '["0010000", "  10  "]'
false

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Answer 15

Husk, 3 bytes

¤=r

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Explanation

¤    -- combine both arguments of ..
 =   -- .. equality ..
  r  -- .. with read

Answer 16

PowerShell, 20 bytes

param($a,$b)+$a-eq$b

Similar to the JavaScript answer, just longer because PowerShell doesn't have currying. Uses + to cast the first string to integer, and then the -equals automatically casts the second string to integer. Output is True/False.

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Answer 17

Jelly, 8 bytes

t€⁶V€€ḌE

Try it online! or see the test suite

35 answers, and no Jelly submission? Takes the argument as a list (["0001", "1 "] for the first example)

How it works

t€⁶V€€ḌE - Main link. Argument: list       e.g.    ["0001", "1    "]
 €       - For €ach element...                     ["0001", "1"]
t        -   trim from both sides...
  ⁶      -   spaces
     €   - For €ach element...
   V€    -   evaluate €ach character               [[0, 0, 0, 1], [1]]
      Ḍ  - Convert from digits                     [1, 1]
       E - Are they equal?                         1

Answer 18

Excel, 8 bytes

=A1-B1=0

Excel does the string to num conversion for us.

(To input as string, prefix values with '.)

Answer 19

PowerShell, 19 bytes

$args-join'-eq'|iex

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-join the argument array ($args) with the string representation of the comparison operator (-eq) then evaluate the expression with Invoke-Expression (iex).

Answer 20

Q (Kdb+), 13 bytes

=/["J"$(x;y)]

Explanation

(x;y) : a list of the two inputs.

"J"$ : casting each input to a long (7j) type from string (10c), which can correctly interpret
white space and leading 0s.

=/ : checks equality over elements in a list (each subsequent pair).
As there is only one pair, returns single boolian 0b/1b.

Answer 21

T-SQL, 35 bytes

Per our standards, data is input via pre-existing table t with varchar fields a and b.

    SELECT IIF(ABS(a)=ABS(b),1,0)FROM t

Returns 1 if they match, 0 if they don't.

A few of SQL's mathematical functions (including ABS, FLOOR and CEILING) will do an implicit conversion to numeric if given string parameters, this is shorter than an explicit CAST(a AS INT) or CONVERT(INT,b), and works in this case since we know the input values are always positive.

IIF is specific to MS SQL 2012 and above, so no guarantee about other implementations.

Answer 22

Excel VBA, 27 16 Bytes

-9 Thanks to @Nayrb and @TaylorScott

[C1]=[A1]-[B1]=0

Where you input the values on the Cells with 'string.

Where x and y are the input Strings and z is a Boolean output.

If CInt(x)=CInt(y) Then z=1

Using CInt

Answer 23

R, 28 27 bytes

!diff(as.double(scan(,'')))

Reads numbers as strings, converts them to doubles and checks if their difference is not zero.

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−1 byte thanks to Giuseppe

Answer 24

Lua, 20 bytes

print(...-arg[2]==0)

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Answer 25

Haskell, 20 bytes

-11 bytes thanks to Laikoni. -2 bytes thanks to Zgarb.

a#b=0+read a==read b

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Answer 26

Gema, 21 characters

*\n*=@cmpn{*;*;0;1;0}

No boolean in Gema. As the @get-switch{}/@set-switch{} functions use 0 and 1 to represent switch statuses, also used 0 and 1.

The 2 strings are passed on separate input lines.

Sample run:

bash-4.4$ gema '*\n*=@cmpn{*;*;0;1;0}' <<< $'0010001\n10001  '
1

bash-4.4$ gema '*\n*=@cmpn{*;*;0;1;0}' <<< $'0010000\n  10  '
0

Answer 27

Perl 5, 9 + 1 (-p) = 10 bytes

$_=$_==<>

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Answer 28

Stacked, 8 bytes

[#~\#~=]

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Explanation

[#~\#~=]   anonymous function
 #~        eval TOS
   \       swap top two
    #~     eval TOS
      =    push equality of top two

Answer 29

Attache, 11 bytes

Same@Map&:N

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This takes an array of strings, such as V["0001", "1 "]. Simply stated, Map&:N is a function that maps N over its argument, and Same checks that the array contains only equal members. (Fun fact: this function works for more than 2 string arguments.)

Answer 30

SNOBOL4 (CSNOBOL4), 42 bytes

	OUTPUT =EQ(EVAL(INPUT),EVAL(INPUT)) 1
END

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Outputs 1 for truthy, nothing for falsey. Since (space) is the concatenation operator in SNOBOL, EVALing a number with leading/trailing spaces yields the number itself, and it also neatly takes care of any leading zeroes. EQ tests for numerical equality, conditionally setting OUTPUT to 1 on Success.