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digitalmars.D.learn - foreach () processing sequence

reply jicman <cabrera wrc.xerox.com> writes:
Greetings!

Imagine this declarion,

char[] str = ["bb", "cc", "aa", "00", "11", "zz", "dd"];

when I do a,

foreach (char[] s; str)
  writefln(s);

assuming that the str array has not been touched or altered in any
way, will the sequence of execution **ALWAYS** follow the sequence
of the array creation?  In other words, will the execution of the
foreach above always display,

bb
cc
aa
00
11
zz
dd

Thanks,

jos�
Feb 06 2007
parent reply Kirk McDonald <kirklin.mcdonald gmail.com> writes:
jicman wrote:

 Greetings!
 
 Imagine this declarion,
 
 char[] str = ["bb", "cc", "aa", "00", "11", "zz", "dd"];
 
 when I do a,
 
 foreach (char[] s; str)
   writefln(s);
 
 assuming that the str array has not been touched or altered in any
 way, will the sequence of execution **ALWAYS** follow the sequence
 of the array creation?  In other words, will the execution of the
 foreach above always display,
 
 bb
 cc
 aa
 00
 11
 zz
 dd
 
 Thanks,
 
 jos�


(Nitpick: The type of str is char[][].)

Yes. An array is an ordered sequence. (As opposed to, say, a hash table, 
which is unordered.)

-- 
Kirk McDonald
Pyd: Wrapping Python with D
http://pyd.dsource.org
Feb 06 2007
parent reply jicman <cabrera wrc.xerox.com> writes:
== Quote from Kirk McDonald's article

 jicman wrote:

 Greetings!

 Imagine this declarion,

 char[] str = ["bb", "cc", "aa", "00", "11", "zz", "dd"];

 when I do a,

 foreach (char[] s; str)
   writefln(s);

 assuming that the str array has not been touched or altered in




any

 way, will the sequence of execution **ALWAYS** follow the




sequence

 of the array creation?  In other words, will the execution of the
 foreach above always display,

 bb
 cc
 aa
 00
 11
 zz
 dd

 Thanks,

 jos�


 (Nitpick: The type of str is char[][].)
 Yes. An array is an ordered sequence. (As opposed to, say, a hash


table,

 which is unordered.)


You're not nitpick, but acurate. :-)

Ok, thanks.
Feb 06 2007
parent reply Johan Granberg <lijat.meREM OVE.gmail.com> writes:
jicman wrote:


 == Quote from Kirk McDonald's article

 jicman wrote:

 Greetings!

 Imagine this declarion,

 char[] str = ["bb", "cc", "aa", "00", "11", "zz", "dd"];

 when I do a,

 foreach (char[] s; str)
   writefln(s);

 assuming that the str array has not been touched or altered in




 any

 way, will the sequence of execution **ALWAYS** follow the




 sequence

 of the array creation?  In other words, will the execution of the
 foreach above always display,

 bb
 cc
 aa
 00
 11
 zz
 dd

 Thanks,

 jos�


 (Nitpick: The type of str is char[][].)
 Yes. An array is an ordered sequence. (As opposed to, say, a hash


 table,

 which is unordered.)


 
 You're not nitpick, but acurate. :-)
 
 Ok, thanks.


I have wondered the same in the past. Is it documented somewhere? otherwise
I think it should be.
Feb 06 2007
parent reply jicman <cabrera wrc.xerox.com> writes:
== Quote from Johan Granberg's article

 jicman wrote:

 == Quote from Kirk McDonald's article

 jicman wrote:

 Greetings!

 Imagine this declarion,

 char[] str = ["bb", "cc", "aa", "00", "11", "zz", "dd"];

 when I do a,

 foreach (char[] s; str)
   writefln(s);

 assuming that the str array has not been touched or altered in




 any

 way, will the sequence of execution **ALWAYS** follow the




 sequence

 of the array creation?  In other words, will the execution of








the

 foreach above always display,

 bb
 cc
 aa
 00
 11
 zz
 dd

 Thanks,

 jos�


 (Nitpick: The type of str is char[][].)
 Yes. An array is an ordered sequence. (As opposed to, say, a






hash

 table,

 which is unordered.)


 You're not nitpick, but acurate. :-)

 Ok, thanks.


 I have wondered the same in the past. Is it documented somewhere?


otherwise

 I think it should be.


I agree.  I was just going to write a function to make sure that the
the creation sequence was the sequence that it would execute on a
foreach().
Feb 06 2007
parent Carlos Santander <csantander619 gmail.com> writes:
jicman escribió:

 == Quote from Johan Granberg's article

 jicman wrote:

 == Quote from Kirk McDonald's article

 jicman wrote:

 Greetings!
 
 Imagine this declarion,
 
 char[] str = ["bb", "cc", "aa", "00", "11", "zz", "dd"];
 
 when I do a,
 
 foreach (char[] s; str) writefln(s);
 
 assuming that the str array has not been touched or altered in




 any

 way, will the sequence of execution **ALWAYS** follow the




 sequence

 of the array creation?  In other words, will the execution of








 the

 foreach above always display,
 
 bb cc aa 00 11 zz dd
 
 Thanks,
 
 jos�


 (Nitpick: The type of str is char[][].) Yes. An array is an ordered
 sequence. (As opposed to, say, a






 hash

 table,

 which is unordered.)


 You're not nitpick, but acurate. :-)
 
 Ok, thanks.


 I have wondered the same in the past. Is it documented somewhere?


 otherwise

 I think it should be.


 
 I agree.  I was just going to write a function to make sure that the the
 creation sequence was the sequence that it would execute on a foreach().


Check http://www.digitalmars.com/d/statement.html#ForeachStatement :

 For foreach, the elements for the array are iterated over starting at index 0
 and continuing to the maximum of the array. For foreach_reverse, the array
 elements are visited in the reverse order.



-- 
Carlos Santander Bernal
Feb 06 2007