Help on string

[SnakeS]

Hi,

I want modify a string as "1122334455 66" in
"11:22:33:44:55 :66"

which is the best method?

Using a RegExp? and if yes how?

Thanks in advance

[Ignacio Machin \( .NET/ C# MVP \)]

Hi,

Does the string has the same length always?
what is the criteria for include the ":"
From the answers to these question depends the solutions.

if you always want to split in two continuos chars you could do something
like this

StringBuilder sb = new StringBuilder()
int start = 0;
string str = "1122334455 66";
while ( str.Length - start > 2 )
{
if ( sb.Length == 0 )
sb.Append( str.substring( start, 2 ) );
else
{
sb.Append( ":" );
sb.Append( str.substring( start, 2 ) );
}
start +=2;
}
This may give you some ideas, just notice that I wrote the text here and it
may have errors

Cheers,

--
Ignacio Machin,
ignacio.machin AT dot.state.fl.us
Florida Department Of Transportation

"SnakeS" <Sn***********@ hotmail.com> wrote in message
news:Cc******** ***********@tor nado.fastwebnet .it...

Hi,

I want modify a string as "1122334455 66" in
"11:22:33:44:55 :66"

which is the best method?

Using a RegExp? and if yes how?

Thanks in advance

[SnakeS]

Yes it's perfect!

I thinked that could be a code more short.

Thanks for all
"Ignacio Machin ( .NET/ C# MVP )" <ignacio.mach in AT dot.state.fl.us > wrote
in message news:%2******** *******@TK2MSFT NGP11.phx.gbl.. .

Hi,

Does the string has the same length always?
what is the criteria for include the ":"
From the answers to these question depends the solutions.

if you always want to split in two continuos chars you could do something
like this

StringBuilder sb = new StringBuilder()
int start = 0;
string str = "1122334455 66";
while ( str.Length - start > 2 )
{
if ( sb.Length == 0 )
sb.Append( str.substring( start, 2 ) );
else
{
sb.Append( ":" );
sb.Append( str.substring( start, 2 ) );
}
start +=2;
}
This may give you some ideas, just notice that I wrote the text here and it may have errors

Cheers,

--
Ignacio Machin,
ignacio.machin AT dot.state.fl.us
Florida Department Of Transportation

"SnakeS" <Sn***********@ hotmail.com> wrote in message
news:Cc******** ***********@tor nado.fastwebnet .it...

Hi,

I want modify a string as "1122334455 66" in
"11:22:33:44:55 :66"

which is the best method?

Using a RegExp? and if yes how?

Thanks in advance

[Jon Skeet [C# MVP]]

C Addison Ritchie <CA************ *@discussions.m icrosoft.com> wrote:

This seems to work well.

using System.Text;
using System.Text.Reg ularExpressions ;

// your string "1122334455 66";
string s = "1122334455 66";

// create the regular expression
Regex re = new Regex("(\\d\\d) ");

// find the matches
MatchCollection matches = re.Matches();

// build the string
string result = String.Format(" {0}:{1}:{2}:{3} :{4}:{5}",
matches[0].Value,
matches[1].Value,
matches[2].Value,
matches[3].Value,
matches[4].Value,
matches[5].Value);

return result;

The input string must be 12 characters long and all numbers. I would
assert that this is true before executing the above code.

That's terrible in terms of performance though - there's really no need
to use a regex here, IMO. Here's code which I believe would be
significantly faster:

if (s.Length != 12)
{
// Whatever your error handling is
}
foreach (char c in s)
{
if (c < '0' || c > '9')
{
// Whatever your error handling is
}
}

return String.Concat(s .Substring(0, 2), ":",
s.Substring(2, 2), ":",
s.Substring(4, 2), ":",
s.Substring(6, 2), ":",
s.Substring(8, 2), ":",
s.Substring(10, 2));

Alternatively, for the last bit:

char[] result = new char[17];
int resultIndex=0;
int origIndex=0;
for (int i=0; i < 6; i++)
{
result[resultIndex++]=s[origIndex++];
result[resultIndex++]=s[origIndex++];
if (i != 5)
{
result[resultIndex++]=':';
}
}
return new string(result);

(That avoids creating too many extra strings.)

I don't know which would be faster - or using a StringBuilder would be
better - but I don't think using a Regex here is a good idea.

--
Jon Skeet - <sk***@pobox.co m>
http://www.pobox.com/~skeet
If replying to the group, please do not mail me too

[C Addison Ritchie]

For asserting that the string is valid you can put this at the top of the method:

Regex ex = new Regex(@"^\d{12} $");
if (!re.IsMatch(s) )
throw new ApplicationExce ption("Not a valid string");

--
C Addison Ritchie, MCSD.NET
Ritch Consulting, Inc.
"SnakeS" wrote:

Hi,

I want modify a string as "1122334455 66" in
"11:22:33:44:55 :66"

which is the best method?

Using a RegExp? and if yes how?

Thanks in advance

[C Addison Ritchie]

Jon you are very correct in your assertions. I threw all three solutions
out there in a loop of 30,000 iterations just for fun. The regular
expression code came in about 1.5 seconds for 30,000 iterations. Your first
solution came in at about 0.1 seconds for 30,000 iterations but your second
solution blew them all away coming in at 0.02 seconds for the 30,000
iterations.

Like you am sure the slow down is in the Regular Expressions.
_______________ __________
C Addison Ritchie, MCSD.NET
Ritch Consulting, Inc.

"Jon Skeet [C# MVP]" <sk***@pobox.co m> wrote in message
news:MP******** *************** *@msnews.micros oft.com...

C Addison Ritchie <CA************ *@discussions.m icrosoft.com> wrote:

This seems to work well.

using System.Text;
using System.Text.Reg ularExpressions ;

// your string "1122334455 66";
string s = "1122334455 66";

// create the regular expression
Regex re = new Regex("(\\d\\d) ");

// find the matches
MatchCollection matches = re.Matches();

// build the string
string result = String.Format(" {0}:{1}:{2}:{3} :{4}:{5}",
matches[0].Value,
matches[1].Value,
matches[2].Value,
matches[3].Value,
matches[4].Value,
matches[5].Value);

return result;

The input string must be 12 characters long and all numbers. I would
assert that this is true before executing the above code.

That's terrible in terms of performance though - there's really no need
to use a regex here, IMO. Here's code which I believe would be
significantly faster:

if (s.Length != 12)
{
// Whatever your error handling is
}
foreach (char c in s)
{
if (c < '0' || c > '9')
{
// Whatever your error handling is
}
}

return String.Concat(s .Substring(0, 2), ":",
s.Substring(2, 2), ":",
s.Substring(4, 2), ":",
s.Substring(6, 2), ":",
s.Substring(8, 2), ":",
s.Substring(10, 2));

Alternatively, for the last bit:

char[] result = new char[17];
int resultIndex=0;
int origIndex=0;
for (int i=0; i < 6; i++)
{
result[resultIndex++]=s[origIndex++];
result[resultIndex++]=s[origIndex++];
if (i != 5)
{
result[resultIndex++]=':';
}
}
return new string(result);

(That avoids creating too many extra strings.)

I don't know which would be faster - or using a StringBuilder would be
better - but I don't think using a Regex here is a good idea.

--
Jon Skeet - <sk***@pobox.co m>
http://www.pobox.com/~skeet
If replying to the group, please do not mail me too

[Ralf B.]

hi

what about this one?

s = "1122334455 66";
for (int i = 2; i < 15; i += 3)
s = s.Insert(i, ":");

regards
rb

"SnakeS" <Sn***********@ hotmail.com> wrote in message
news:Cc******** ***********@tor nado.fastwebnet .it...

Hi,

I want modify a string as "1122334455 66" in
"11:22:33:44:55 :66"

which is the best method?

Using a RegExp? and if yes how?

Thanks in advance

[Ignacio Machin \( .NET/ C# MVP \)]

Hi,

You are creating lots of several strings, it;s much better to use a
StringBuilder, see my other post for a possible solution.

Cheers,

--
Ignacio Machin,
ignacio.machin AT dot.state.fl.us
Florida Department Of Transportation
"Ralf B." <ra*********@mo rtgageuk.com> wrote in message
news:uw******** ******@TK2MSFTN GP12.phx.gbl...

hi

what about this one?

s = "1122334455 66";
for (int i = 2; i < 15; i += 3)
s = s.Insert(i, ":");

regards
rb

"SnakeS" <Sn***********@ hotmail.com> wrote in message
news:Cc******** ***********@tor nado.fastwebnet .it...

Hi,

I want modify a string as "1122334455 66" in
"11:22:33:44:55 :66"

which is the best method?

Using a RegExp? and if yes how?

Thanks in advance

[Ralf B.]

hi

i am creating 5 substrings..

your solution works but has a lot of code..

substring() produces temp strings, too. Also, I suppose StringBuilder
internally works with temporary strings as well.

regards
rb

"Ignacio Machin ( .NET/ C# MVP )" <ignacio.mach in AT dot.state.fl.us > wrote
in message news:ei******** ******@TK2MSFTN GP11.phx.gbl...

Hi,

You are creating lots of several strings, it;s much better to use a
StringBuilder, see my other post for a possible solution.

Cheers,

--
Ignacio Machin,
ignacio.machin AT dot.state.fl.us
Florida Department Of Transportation
"Ralf B." <ra*********@mo rtgageuk.com> wrote in message
news:uw******** ******@TK2MSFTN GP12.phx.gbl...

hi

what about this one?

s = "1122334455 66";
for (int i = 2; i < 15; i += 3)
s = s.Insert(i, ":");

regards
rb

"SnakeS" <Sn***********@ hotmail.com> wrote in message
news:Cc******** ***********@tor nado.fastwebnet .it...

Hi,

I want modify a string as "1122334455 66" in
"11:22:33:44:55 :66"

which is the best method?

Using a RegExp? and if yes how?

Thanks in advance

[Jon Skeet [C# MVP]]

Ralf B. <ra*********@mo rtgageuk.com> wrote:

i am creating 5 substrings..

your solution works but has a lot of code..

substring() produces temp strings, too. Also, I suppose StringBuilder
internally works with temporary strings as well.

StringBuilder uses a temporary string if it needs to be expanded, but
if you give it the right size to start with, it shouldn't need any
temporary measures.

--
Jon Skeet - <sk***@pobox.co m>
http://www.pobox.com/~skeet
If replying to the group, please do not mail me too