regex help

[Howard]

I need to write a regular exp to replace more than 1 space to a single space
input:
this is a computer program

output
this is a computer program

output = Regex.Replace(input, "something here", " ")
thanks

Howard

[KH]

@"\s+"
"Howard" wrote:

I need to write a regular exp to replace more than 1 space to a single space
input:
this is a computer program

output
this is a computer program

output = Regex.Replace(input, "something here", " ")
thanks

Howard

[Kevin Spencer]

That will match *any* white space character. To replace only spaces:

[ ]+

--
HTH,

Kevin Spencer
Microsoft MVP
Professional Numbskull

Show me your certification without works,
and I'll show my certification
*by* my works.

"KH" <[e-mail]> wrote in message
news:9E**********************************@microsof t.com...

@"\s+"
"Howard" wrote:

I need to write a regular exp to replace more than 1 space to a single
space
input:
this is a computer program

output
this is a computer program

output = Regex.Replace(input, "something here", " ")
thanks

Howard

[Rocky]

This will do it.

output = Regex.Replace("this is a computer program", "[ ]{2,}", " ");
"Kevin Spencer" <ke***@DIESPAMMERSDIEtakempis.com> wrote in message
news:Ol**************@TK2MSFTNGP02.phx.gbl...

That will match *any* white space character. To replace only spaces:

[ ]+

--
HTH,

Kevin Spencer
Microsoft MVP
Professional Numbskull

Show me your certification without works,
and I'll show my certification
*by* my works.

"KH" <[e-mail]> wrote in message
news:9E**********************************@microsof t.com...

@"\s+"
"Howard" wrote:

I need to write a regular exp to replace more than 1 space to a single
space
input:
this is a computer program

output
this is a computer program

output = Regex.Replace(input, "something here", " ")
thanks

Howard

[Chris Fulstow]

How about this?

string str = "this is a computer program";
for (;str.IndexOf(" ") > -1; str=str.Replace(" ", " "));

Joking aside, I ran a quick (and very unscientific) benchmark to
compare this against the regular expression method, and it's quicker
for small strings with only a few multiple spaces. Might be worth
rewriting as a while loop if you're actually going to use it though
:¬)

Further to Rocky's reply, the square brackets are optional, so you
could have just:
" {2,}"

Personally, I think the brackets make it more readable, so I'd keep
them in.

Chris

[Otis Mukinfus]

On Sat, 8 Apr 2006 14:51:51 -0700, "Howard" <ho*******@yahoo.com> wrote:

I need to write a regular exp to replace more than 1 space to a single space
input:
this is a computer program

output
this is a computer program

output = Regex.Replace(input, "something here", " ")
thanks

Howard

The other folks have already answered your question. Below is a link to a tool
that can help you design regular expressions. Since I am no regular expressions
expert, I use it all the time ;o)

http://www.gotdotnet.com/Community/U...1-4ee2729d7322

Good luck with your project,

Otis Mukinfus
http://www.arltex.com
http://www.tomchilders.com

[Jon Skeet [C# MVP]]

Chris Fulstow <ch**********@hotmail.com> wrote:

How about this?

string str = "this is a computer program";
for (;str.IndexOf(" ") > -1; str=str.Replace(" ", " "));

Joking aside, I ran a quick (and very unscientific) benchmark to
compare this against the regular expression method, and it's quicker
for small strings with only a few multiple spaces. Might be worth
rewriting as a while loop if you're actually going to use it though
:¬)

I would certainly have written it as a while loop. However, you should
be aware that the above can go into an infinite loop. Scary as it
sounds, if there's a "zero-width non-joiner character" between two
spaces, IndexOf will find it but Replace won't. Try running the above
on:

"hello \u200c there"

Scary, eh?

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

[Lucian Wischik]

"Chris Fulstow" <ch**********@hotmail.com> wrote:

string str = "this is a computer program";
for (;str.IndexOf(" ") > -1; str=str.Replace(" ", " "));
Joking aside, I ran a quick (and very unscientific) benchmark to
compare this against the regular expression method

I'd go straight for this !! ... (untested c++)

const char *src="this is a computer program";
char *dst = new char[strlen(src)];
bool space=false;

while (*src!=0)
{ if (*src==' ' && space) src++;
else {space=(*src==' '); *dst++=*src++;}
}

--
Lucian

[Rocky]

> I'd go straight for this !! ... (untested c++)

I didn't know this was C++ newsgroup.
"Lucian Wischik" <lu***@wischik.com> wrote in message
news:3d********************************@4ax.com...

"Chris Fulstow" <ch**********@hotmail.com> wrote:

string str = "this is a computer program";
for (;str.IndexOf(" ") > -1; str=str.Replace(" ", " "));
Joking aside, I ran a quick (and very unscientific) benchmark to
compare this against the regular expression method

I'd go straight for this !! ... (untested c++)

const char *src="this is a computer program";
char *dst = new char[strlen(src)];
bool space=false;

while (*src!=0)
{ if (*src==' ' && space) src++;
else {space=(*src==' '); *dst++=*src++;}
}

--
Lucian

[Frank van Dijk]

Rocky schreef:

I'd go straight for this !! ... (untested c++)

I didn't know this was C++ newsgroup.

That's ok... I wouldn't call that stuff below C++.


"Lucian Wischik" <lu***@wischik.com> wrote in message
news:3d********************************@4ax.com...

"Chris Fulstow" <ch**********@hotmail.com> wrote:

string str = "this is a computer program";
for (;str.IndexOf(" ") > -1; str=str.Replace(" ", " "));
Joking aside, I ran a quick (and very unscientific) benchmark to
compare this against the regular expression method

I'd go straight for this !! ... (untested c++)

const char *src="this is a computer program";
char *dst = new char[strlen(src)];
bool space=false;

while (*src!=0)
{ if (*src==' ' && space) src++;
else {space=(*src==' '); *dst++=*src++;}
}

--
Lucian

[Rocky]

Try it in C# and see what you get smart guy. Besides, the code doesn't even
work in C++ (until I fixed it).

"Frank van Dijk" <f.******@home.nl> wrote in message
news:e1**********@news1.zwoll1.ov.home.nl...

Rocky schreef:

I'd go straight for this !! ... (untested c++)

I didn't know this was C++ newsgroup.

That's ok... I wouldn't call that stuff below C++.

"Lucian Wischik" <lu***@wischik.com> wrote in message
news:3d********************************@4ax.com...

"Chris Fulstow" <ch**********@hotmail.com> wrote:

string str = "this is a computer program";
for (;str.IndexOf(" ") > -1; str=str.Replace(" ", " "));
Joking aside, I ran a quick (and very unscientific) benchmark to
compare this against the regular expression method
I'd go straight for this !! ... (untested c++)

const char *src="this is a computer program";
char *dst = new char[strlen(src)];
bool space=false;

while (*src!=0)
{ if (*src==' ' && space) src++;
else {space=(*src==' '); *dst++=*src++;}
}

--
Lucian

[Rocky]

Just for giggles, here is the code in C#. Report any errors to the
authorities immediately.
public char[] EnsureSingleSpacing(string str)
{

unsafe
{

string src = str;
char[] dst = new char[src.Length - 1];

fixed (char* p = src)
fixed (char* p1 = dst)
{
char* temp = p;
char* temp2 = p1;
char prev = ' ';
while (*temp != 0)
{

if (*temp == ' ' && prev == ' ' ) temp++;

else
{
if (*temp !='\n')prev = *temp;
*temp2++ = *temp++;
}

}
*temp2++ = '\0';

return dst;

}

}

}

"Frank van Dijk" <f.******@home.nl> wrote in message
news:e1**********@news1.zwoll1.ov.home.nl...

Rocky schreef:

I'd go straight for this !! ... (untested c++)

I didn't know this was C++ newsgroup.

That's ok... I wouldn't call that stuff below C++.

"Lucian Wischik" <lu***@wischik.com> wrote in message
news:3d********************************@4ax.com...

"Chris Fulstow" <ch**********@hotmail.com> wrote:

string str = "this is a computer program";
for (;str.IndexOf(" ") > -1; str=str.Replace(" ", " "));
Joking aside, I ran a quick (and very unscientific) benchmark to
compare this against the regular expression method
I'd go straight for this !! ... (untested c++)

const char *src="this is a computer program";
char *dst = new char[strlen(src)];
bool space=false;

while (*src!=0)
{ if (*src==' ' && space) src++;
else {space=(*src==' '); *dst++=*src++;}
}

--
Lucian

[Frank van Dijk]

Rocky schreef:

Try it in C# and see what you get smart guy. Besides, the code doesn't even
work in C++ (until I fixed it).
My point being that while it might pass a C++ compiler it's actually C
with the accidental use of a few C++ keywords. The bugs (memory leak,
string length, string termination) perhaps arising from the C-ness.

Lucian Wischik probably posted his snippet as an ironic comment anyway,
so...

..

"Frank van Dijk" <f.******@home.nl> wrote in message
news:e1**********@news1.zwoll1.ov.home.nl...

Rocky schreef:

I'd go straight for this !! ... (untested c++)
I didn't know this was C++ newsgroup.

That's ok... I wouldn't call that stuff below C++.

"Lucian Wischik" <lu***@wischik.com> wrote in message
news:3d********************************@4ax.com ...
"Chris Fulstow" <ch**********@hotmail.com> wrote:
>string str = "this is a computer program";
>for (;str.IndexOf(" ") > -1; str=str.Replace(" ", " "));
>Joking aside, I ran a quick (and very unscientific) benchmark to
>compare this against the regular expression method
I'd go straight for this !! ... (untested c++)

const char *src="this is a computer program";
char *dst = new char[strlen(src)];
bool space=false;

while (*src!=0)
{ if (*src==' ' && space) src++;
else {space=(*src==' '); *dst++=*src++;}
}

--
Lucian

[Rocky]

"Rocky" <no*****@nowhere.com> wrote in message
news:ez**************@TK2MSFTNGP03.phx.gbl...

Just for giggles, here is the code in C#. Report any errors to the
authorities immediately.
public char[] EnsureSingleSpacing(string str)
{

unsafe
{

string src = str;
char[] dst = new char[src.Length - 1];

fixed (char* p = src)
fixed (char* p1 = dst)
{
char* temp = p;
char* temp2 = p1;
char prev = ' ';
while (*temp != 0)
{

if (*temp == ' ' && prev == ' ' ) temp++;

else
{
if (*temp !='\n')prev = *temp;
*temp2++ = *temp++;
}

}
*temp2++ = '\0';

return dst;

}

}

}

"Frank van Dijk" <f.******@home.nl> wrote in message
news:e1**********@news1.zwoll1.ov.home.nl...

Rocky schreef:

I'd go straight for this !! ... (untested c++)
I didn't know this was C++ newsgroup.

That's ok... I wouldn't call that stuff below C++.

"Lucian Wischik" <lu***@wischik.com> wrote in message
news:3d********************************@4ax.com...

"Chris Fulstow" <ch**********@hotmail.com> wrote:

>string str = "this is a computer program";
>for (;str.IndexOf(" ") > -1; str=str.Replace(" ", " "));
>Joking aside, I ran a quick (and very unscientific) benchmark to
>compare this against the regular expression method
I'd go straight for this !! ... (untested c++)

const char *src="this is a computer program";
char *dst = new char[strlen(src)];
bool space=false;

while (*src!=0)
{ if (*src==' ' && space) src++;
else {space=(*src==' '); *dst++=*src++;}
}

--
Lucian

[Rocky]

I think it would be better to return a string instead of a char[]. Don't you
think?
// Updated code
public string EnsureSingleSpacing(string str)
{

// Other Code Omitted
return new string(p1);

}

"Rocky" <no*****@nowhere.com> wrote in message
news:ez**************@TK2MSFTNGP03.phx.gbl...

Just for giggles, here is the code in C#. Report any errors to the
authorities immediately.
public char[] EnsureSingleSpacing(string str)
{

unsafe
{

string src = str;
char[] dst = new char[src.Length - 1];

fixed (char* p = src)
fixed (char* p1 = dst)
{
char* temp = p;
char* temp2 = p1;
char prev = ' ';
while (*temp != 0)
{

if (*temp == ' ' && prev == ' ' ) temp++;

else
{
if (*temp !='\n')prev = *temp;
*temp2++ = *temp++;
}

}
*temp2++ = '\0';

return dst;

}

}

}

"Frank van Dijk" <f.******@home.nl> wrote in message
news:e1**********@news1.zwoll1.ov.home.nl...

Rocky schreef:

I'd go straight for this !! ... (untested c++)
I didn't know this was C++ newsgroup.

That's ok... I wouldn't call that stuff below C++.

"Lucian Wischik" <lu***@wischik.com> wrote in message
news:3d********************************@4ax.com...

"Chris Fulstow" <ch**********@hotmail.com> wrote:

>string str = "this is a computer program";
>for (;str.IndexOf(" ") > -1; str=str.Replace(" ", " "));
>Joking aside, I ran a quick (and very unscientific) benchmark to
>compare this against the regular expression method
I'd go straight for this !! ... (untested c++)

const char *src="this is a computer program";
char *dst = new char[strlen(src)];
bool space=false;

while (*src!=0)
{ if (*src==' ' && space) src++;
else {space=(*src==' '); *dst++=*src++;}
}

--
Lucian

[Frank van Dijk]

Rocky schreef:

I think it would be better to return a string instead of a char[]. Don't you
think?
yes


return new string(p1);

return new string(dst) eliminates the need for a terminating 0.

Just for giggles, here is the code in C#. Report any errors to the
authorities immediately.
dear authorities,


public char[] EnsureSingleSpacing(string str)
{

unsafe
{

string src = str;
redundant.
char[] dst = new char[src.Length - 1];
src.Length+1 if you use a terminating 0, src.Length otherwise.

fixed (char* p = src)
fixed (char* p1 = dst)
{
char* temp = p;
char* temp2 = p1;
char prev = ' ';
this causes a space to be blown away if it's the first character in the
string.
while (*temp != 0)
{

if (*temp == ' ' && prev == ' ' ) temp++;

else
{
if (*temp !='\n')prev = *temp;
huh ? what is special about newline ?
*temp2++ = *temp++;
}

}
*temp2++ = '\0';
only needed if using p1 to construct your string. dst is a counted array.

return dst;

}

}

}

[Rocky]

>> src.Length + 1 if you use a terminating 0 <<
Yep, I was thinking about VB at the time

return new string(dst) eliminates the need for a terminating 0 << Nope. Did you try this? It returns the FULL array length (except for a
string with NO spaces)

Try this:
string result = EnsureSingleSpacing(" this is a computer
program ");
Console.WriteLine(result.Length);
It will return 48 instead of 27.

Then this:
string result = EnsureSingleSpacing("ALineWithNoSpaces");
Console.WriteLine(result.Length);
It will return 17, the exact number.

this causes a space to be blown away if it's the first character in the
string <<

Yes, it does. That's the way I wanted it. No spaces at the beginning of each
line.
huh ? what is special about newline ? > You could get too many spaces. Everything is SINGLE spaced. See above.

I really appreciate you critiquing my code. It makes me feel special. Maybe
you could show me some of your code so I could repay the favor?

"Frank van Dijk" <f.******@home.nl> wrote in message
news:e1**********@news4.zwoll1.ov.home.nl... Rocky schreef:

I think it would be better to return a string instead of a char[]. Don't
you think?

yes

return new string(p1);

return new string(dst) eliminates the need for a terminating 0.
Just for giggles, here is the code in C#. Report any errors to the
authorities immediately.
dear authorities,
public char[] EnsureSingleSpacing(string str)
{

unsafe
{

string src = str;
redundant.
char[] dst = new char[src.Length - 1];
src.Length+1 if you use a terminating 0, src.Length otherwise.

fixed (char* p = src)
fixed (char* p1 = dst)
{
char* temp = p;
char* temp2 = p1;
char prev = ' ';
this causes a space to be blown away if it's the first character in the
string.
while (*temp != 0)
{

if (*temp == ' ' && prev == ' ' ) temp++;

else
{
if (*temp !='\n')prev = *temp;
huh ? what is special about newline ?
*temp2++ = *temp++;
}

}
*temp2++ = '\0';
only needed if using p1 to construct your string. dst is a counted array.

return dst;

}

}

}

[Frank van Dijk]

Rocky schreef:

src.Length + 1 if you use a terminating 0 <<
Yep, I was thinking about VB at the time

return new string(dst) eliminates the need for a terminating 0 <<
Nope. Did you try this? It returns the FULL array length (except for a
string with NO spaces)
You're right. Should be something like new string(dst,0,temp2-p1). Which
makes it slightly less attractive.

this causes a space to be blown away if it's the first character in the
string <<

Yes, it does. That's the way I wanted it. No spaces at the beginning of each
line.

huh ? what is special about newline ? >

You could get too many spaces. Everything is SINGLE spaced. See above.

Oh, I foolishly interpreted "here is the code in C#" as implying that
like the other samples in this thread, "the code" was intended to solve
the OP's problem.

I really appreciate you critiquing my code. It makes me feel special.
Anything to oblige.
Maybe you could show me some of your code so I could repay the favor?

Sure. To stay on topic and because I love the 'closure' feature of C#,
here's a silly solution to the OP's problem using an anonymous method.
In real life I'd just use the regexp substitution though. And yes, I am
aware of the existence of the foreach keyword.

static string JustOneSpace(string s) {
StringBuilder result=new StringBuilder();
bool wasSpace=false;
Array.ForEach(s.ToCharArray(), delegate(char c) {
if (!wasSpace || c!=' ') {
result.Append(c);
}
wasSpace = c == ' '; });
return result.ToString();
}

Here's a rough equivalent in C++. I hope no-one objects to me posting it
in this newsgroup :-) In real life I'd use a regexp subst here too.

bool is_both_space(const char c1,const char c2) {
return c1==' ' && c2==' ';
}

string just_one_space(const string& s) {
string result;
unique_copy(s.begin(),s.end(),inserter(result,resu lt.begin()),
is_both_space);
return result;
}