• MachineCode (11/14) Oct 15 2014 Is there one function in the Phobos library to check if give an
• thedeemon (3/5) Oct 15 2014 auto n = min(a.length, b.length);
• =?UTF-8?B?QWxpIMOHZWhyZWxp?= (9/22) Oct 15 2014 import std.algorithm;

"MachineCode" <netorib94 gmail.com> writes:

Is there one function in the Phobos library to check if give an 
array is equal to first elements in another array? e.g, f(a, b) 
the entire b array must match to first elements in a and then 
return true otherwise false, ie:

 a[0 .. b.length] == b

probably there's no such a function (but I wouldn't find bad if 
there was) in the D's library so what's a good name (that'a 
descriptive) to such a function?

btw, what it solves is:

 if(a.length >= b1.length && a[0 .. b1.length] == b1) { ... }
 if(a.length >= b2.length && a[0 .. b2.length] == b2) { ... }

since if bx.length < a.length is valid I can't remove all the 
a.length >= bx.length checks otherwise I can have a range 
violation error

"thedeemon" <dlang thedeemon.com> writes:

On Thursday, 16 October 2014 at 04:35:13 UTC, MachineCode wrote:
 Is there one function in the Phobos library to check if give an 
 array is equal to first elements in another array?

auto n = min(a.length, b.length);
if (a[0..n] == b[0..n]) ...

=?UTF-8?B?QWxpIMOHZWhyZWxp?= <acehreli yahoo.com> writes:

On 10/15/2014 09:35 PM, MachineCode wrote:
 Is there one function in the Phobos library to check if give an array is
 equal to first elements in another array? e.g, f(a, b) the entire b
 array must match to first elements in a and then return true otherwise
 false, ie:

 a[0 .. b.length] == b

 probably there's no such a function (but I wouldn't find bad if there
 was) in the D's library so what's a good name (that'a descriptive) to
 such a function?

 btw, what it solves is:

 if(a.length >= b1.length && a[0 .. b1.length] == b1) { ... }
 if(a.length >= b2.length && a[0 .. b2.length] == b2) { ... }

 since if bx.length < a.length is valid I can't remove all the a.length
  >= bx.length checks otherwise I can have a range violation error

import std.algorithm;

void main()
{
     auto a = [ 1, 42, 100, 7 ];
     auto b = [ 1, 42 ];
     assert(a.startsWith(b));
}

Ali