regular expression help

[Jeremy]

I created a regular expression to parse a line in a csv file;

(\"(?<word>[^\"]+|\"\")*\"|(?<word>[^,]*))

It is capable of taking a line such as field1,field2,field
3,123.12,"1,234.56" and matching each value between the commas into the word
group, so I get
field1
field2
field 3
123.12
1,234.56

My problem is that if I perform a split, or match on a string like
1,1,"123.345" I will get 6 matches back instead of 3.

const string strDelimiter =
"(\\\"(?<word>[^\\\"]+|\\\"\\\")*\\\"|(?<word>[^,]*))";
string strText = "1,1,\"12,212.43\"";
string[] strParts = System.Text.RegularExpressions.Regex.Split(strText ,
strDelimiter,System.Text.RegularExpressions.RegexOptions.Compiled |
System.Text.RegularExpressions.RegexOptions.ExplicitCapture);

System.Text.RegularExpressions.MatchCollection pMatches =
System.Text.RegularExpressions.Regex.Matches(strText ,
strDelimiter,System.Text.RegularExpressions.RegexOptions.ExplicitCapture);
Split returns 13 values, as shown below, and Matches returns 6 items. How
can I just extract the 3 items?

strParts {Dimensions:[13]} string[]
[0] "" string
[1] "1" string
[2] "" string
[3] "" string
[4] "," string
[5] "1" string
[6] "" string
[7] "" string
[8] "," string
[9] "30,478.50" string
[10] "" string
[11] "" string
[12] "" string

 

[Kevin Spencer]

Use the following:

\s*(??<word>"[^"]*")|(?<!")(?<word>[^,"]*)(?<!"))\s*

Rather than splitting, it captures all of the elements without the commas
(and spaces) between them. The way it works is this:

It uses a non-capturing group to indicate that either of the two choices may
be preceded and followed by 0 or more spaces. This eliminates preceding and
following spaces from the groups.

It will capture one of two options:

A quote followed by any sequence of characters that is not a quote, followed
by a quote.
Any sequence of characters that is NOT preceded by a quote and does not
contain either quotes or commas, and is NOT followed by a quote.

The group "word" will give you all the matches that you want.

--
HTH,

Kevin Spencer
Chicken Salad Surgeon
Microsoft MVP

 

[Jeremy]

Thanks for the regex.

If you perform a match, you will still get 5 matches though on text such as
1,4,"32,760.00"
You will get "1", "", "4", "", "32.760.00"


I don't understand why it returns 2 empty strings.. any ideas?

Code:

System.Text.RegularExpressions.MatchCollection pMatches =
System.Text.RegularExpressions.Regex.Matches(strText, strRegex,
System.Text.RegularExpressions.RegexOptions.ExplicitCapture);
foreach (System.Text.RegularExpressions.Match pMatch in pMatches)
{
System.Text.RegularExpressions.Group pGroup = pMatch.Groups["word"];
string strValue = pGroup.Value;
}

Use the following:

\s*(??<word>"[^"]*")|(?<!")(?<word>[^,"]*)(?<!"))\s*

Rather than splitting, it captures all of the elements without the commas
(and spaces) between them. The way it works is this:

It uses a non-capturing group to indicate that either of the two choices
may be preceded and followed by 0 or more spaces. This eliminates
preceding and following spaces from the groups.

It will capture one of two options:

A quote followed by any sequence of characters that is not a quote,
followed by a quote.
Any sequence of characters that is NOT preceded by a quote and does not
contain either quotes or commas, and is NOT followed by a quote.

The group "word" will give you all the matches that you want.

--
HTH,

Kevin Spencer
Chicken Salad Surgeon
Microsoft MVP

I created a regular expression to parse a line in a csv file;

(\"(?<word>[^\"]+|\"\")*\"|(?<word>[^,]*))

It is capable of taking a line such as field1,field2,field
3,123.12,"1,234.56" and matching each value between the commas into the
word group, so I get
field1
field2
field 3
123.12
1,234.56

My problem is that if I perform a split, or match on a string like
1,1,"123.345" I will get 6 matches back instead of 3.

const string strDelimiter =
"(\\\"(?<word>[^\\\"]+|\\\"\\\")*\\\"|(?<word>[^,]*))";
string strText = "1,1,\"12,212.43\"";
string[] strParts = System.Text.RegularExpressions.Regex.Split(strText ,
strDelimiter,System.Text.RegularExpressions.RegexOptions.Compiled |
System.Text.RegularExpressions.RegexOptions.ExplicitCapture);

System.Text.RegularExpressions.MatchCollection pMatches =
System.Text.RegularExpressions.Regex.Matches(strText ,
strDelimiter,System.Text.RegularExpressions.RegexOptions.ExplicitCapture);
Split returns 13 values, as shown below, and Matches returns 6 items.
How can I just extract the 3 items?

strParts {Dimensions:[13]} string[]
[0] "" string
[1] "1" string
[2] "" string
[3] "" string
[4] "," string
[5] "1" string
[6] "" string
[7] "" string
[8] "," string
[9] "30,478.50" string
[10] "" string
[11] "" string
[12] "" string

 

[Kevin Spencer]

I don't know why it does. It has something to do with the internal rules of
the .Net Regex engine. But all you have to do is check for a 0 Length on
each match.

--
HTH,

Kevin Spencer
Chicken Salad Surgeon
Microsoft MVP

Thanks for the regex.

If you perform a match, you will still get 5 matches though on text such
as
1,4,"32,760.00"
You will get "1", "", "4", "", "32.760.00"


I don't understand why it returns 2 empty strings.. any ideas?

Code:

System.Text.RegularExpressions.MatchCollection pMatches =
System.Text.RegularExpressions.Regex.Matches(strText, strRegex,
System.Text.RegularExpressions.RegexOptions.ExplicitCapture);
foreach (System.Text.RegularExpressions.Match pMatch in pMatches)
{
System.Text.RegularExpressions.Group pGroup = pMatch.Groups["word"];
string strValue = pGroup.Value;
}

Use the following:

\s*(??<word>"[^"]*")|(?<!")(?<word>[^,"]*)(?<!"))\s*

Rather than splitting, it captures all of the elements without the commas
(and spaces) between them. The way it works is this:

It uses a non-capturing group to indicate that either of the two choices
may be preceded and followed by 0 or more spaces. This eliminates
preceding and following spaces from the groups.

It will capture one of two options:

A quote followed by any sequence of characters that is not a quote,
followed by a quote.
Any sequence of characters that is NOT preceded by a quote and does not
contain either quotes or commas, and is NOT followed by a quote.

The group "word" will give you all the matches that you want.

--
HTH,

Kevin Spencer
Chicken Salad Surgeon
Microsoft MVP

I created a regular expression to parse a line in a csv file;

(\"(?<word>[^\"]+|\"\")*\"|(?<word>[^,]*))

It is capable of taking a line such as field1,field2,field
3,123.12,"1,234.56" and matching each value between the commas into the
word group, so I get
field1
field2
field 3
123.12
1,234.56

My problem is that if I perform a split, or match on a string like
1,1,"123.345" I will get 6 matches back instead of 3.

const string strDelimiter =
"(\\\"(?<word>[^\\\"]+|\\\"\\\")*\\\"|(?<word>[^,]*))";
string strText = "1,1,\"12,212.43\"";
string[] strParts = System.Text.RegularExpressions.Regex.Split(strText ,
strDelimiter,System.Text.RegularExpressions.RegexOptions.Compiled |
System.Text.RegularExpressions.RegexOptions.ExplicitCapture);

System.Text.RegularExpressions.MatchCollection pMatches =
System.Text.RegularExpressions.Regex.Matches(strText ,
strDelimiter,System.Text.RegularExpressions.RegexOptions.ExplicitCapture);
Split returns 13 values, as shown below, and Matches returns 6 items.
How can I just extract the 3 items?

strParts {Dimensions:[13]} string[]
[0] "" string
[1] "1" string
[2] "" string
[3] "" string
[4] "," string
[5] "1" string
[6] "" string
[7] "" string
[8] "," string
[9] "30,478.50" string
[10] "" string
[11] "" string
[12] "" string

 

[Jesse Houwing]

Hello Jeremy,

Thanks for the regex.

If you perform a match, you will still get 5 matches though on text
such as
1,4,"32,760.00"
You will get "1", "", "4", "", "32.760.00"
I don't understand why it returns 2 empty strings.. any ideas?

Basically because if you remove everything that is optional in the regex
below you end up with an empty regex:


\s*(??<word>"[^"]*")|(?<!")(?<word>[^,"]*)(?<!"))\s*

\s* is optional
(??<word>"[^"]*")|(?<!")(?<word>[^,"]*)(?<!")) is optional because one
of the parts of the alteration (namely (?<!")(?<word>[^,"]*)(?<!") is optional)
\s* is optional

So the regex engine will try to match on every character in the string:
1 stop, first match is found
, comma doesn't match, but the nothingness behind it does.
4 stop, third match is found
, comma doesn't match, but the nothingness behind it does.
"32,760.00" and the last match is found.

You can ueasily demonstrate this by replacing instead of matching. Replace
the matches with something like $ and all the places where a match are found
are visible:

using the above regex and $$ as replacement pattern you will get the following
result:


The issue can be solved in two ways:

1) make sure there are no optional parts:
\s*(??<word>"[^"]*")|(?<!")(?<word>[^,"]+)(?<!"))\s*

2) match the content of what you want to match even more closely within the
pattern of beginnign of the line, comma separated values, end of the line:
(?<=^|,)\s*("(?<word>[^"]*)"|(?<word>[^",]*?))\s*(?=,|$)
This last regex also removes any whitespace around the non quoted values
and removes the quotes from quoted values.

Jesse

Code:

System.Text.RegularExpressions.MatchCollection pMatches =
System.Text.RegularExpressions.Regex.Matches(strText, strRegex,
System.Text.RegularExpressions.RegexOptions.ExplicitCapture);
foreach (System.Text.RegularExpressions.Match pMatch in pMatches)
{
System.Text.RegularExpressions.Group pGroup =
pMatch.Groups["word"];
string strValue = pGroup.Value;
}

Use the following:

\s*(??<word>"[^"]*")|(?<!")(?<word>[^,"]*)(?<!"))\s*

Rather than splitting, it captures all of the elements without the
commas (and spaces) between them. The way it works is this:

It uses a non-capturing group to indicate that either of the two
choices may be preceded and followed by 0 or more spaces. This
eliminates preceding and following spaces from the groups.

It will capture one of two options:

A quote followed by any sequence of characters that is not a quote,
followed by a quote.
Any sequence of characters that is NOT preceded by a quote and does
not
contain either quotes or commas, and is NOT followed by a quote.
The group "word" will give you all the matches that you want.

-- HTH,

Kevin Spencer
Chicken Salad Surgeon
Microsoft MVP

I created a regular expression to parse a line in a csv file;

(\"(?<word>[^\"]+|\"\")*\"|(?<word>[^,]*))

It is capable of taking a line such as field1,field2,field
3,123.12,"1,234.56" and matching each value between the commas into
the
word group, so I get
field1
field2
field 3
123.12
1,234.56
My problem is that if I perform a split, or match on a string like
1,1,"123.345" I will get 6 matches back instead of 3.

const string strDelimiter =
"(\\\"(?<word>[^\\\"]+|\\\"\\\")*\\\"|(?<word>[^,]*))";
string strText = "1,1,\"12,212.43\"";
string[] strParts =
System.Text.RegularExpressions.Regex.Split(strText ,
strDelimiter,System.Text.RegularExpressions.RegexOptions.Compiled |
System.Text.RegularExpressions.RegexOptions.ExplicitCapture);
System.Text.RegularExpressions.MatchCollection pMatches =
System.Text.RegularExpressions.Regex.Matches(strText ,
strDelimiter,System.Text.RegularExpressions.RegexOptions.ExplicitCap
ture);
Split returns 13 values, as shown below, and Matches returns 6
items.
How can I just extract the 3 items?
strParts {Dimensions:[13]} string[]
[0] "" string
[1] "1" string
[2] "" string
[3] "" string
[4] "," string
[5] "1" string
[6] "" string
[7] "" string
[8] "," string
[9] "30,478.50" string
[10] "" string
[11] "" string
[12] "" string

 

[Jesse Houwing]

Hello Jeremy,

I don't know why it does. It has something to do with the internal
rules of the .Net Regex engine. But all you have to do is check for a
0 Length on each match.

Kevin Spencer
Chicken Salad Surgeon
Microsoft MVP

Basically because if you remove everything that is optional in the regex
below you end up with an empty regex:


\s*(??<word>"[^"]*")|(?<!")(?<word>[^,"]*)(?<!"))\s*

\s* is optional
(??<word>"[^"]*")|(?<!")(?<word>[^,"]*)(?<!")) is optional because one
of the parts of the alteration (namely (?<!")(?<word>[^,"]*)(?<!") is optional)
\s* is optional

So the regex engine will try to match on every character in the string:
1 stop, first match is found
, comma doesn't match, but the nothingness in front of it does.
4 stop, third match is found
, comma doesn't match, but the nothingness in front of it does.
"32,760.00" and the last match is found.

You can ueasily demonstrate this by replacing instead of matching. Replace
the matches with something like $ and all the places where a match are found
are visible:

using the above regex and $$ as replacement pattern you will get the following
result:
$$,$$,$

So as you can see that it matches a second value just before each ",".

The issue can be solved in two ways:

1) make sure there are no optional parts:
\s*(??<word>"[^"]*")|(?<!")(?<word>[^,"]+)(?<!"))\s*

2) match the content of what you want to match even more closely within the
pattern of beginnign of the line, comma separated values, end of the line:
(?<=^|,)\s*("(?<word>[^"]*)"|(?<word>[^",]*?))\s*(?=,|$)
This last regex also removes any whitespace around the non quoted values
and removes the quotes from quoted values.

I hope this explains it for you. If you have any more questions don't hesitate
to ask.

--
Jesse Houwing
jesse.houwing at sogeti.nl

Code:

System.Text.RegularExpressions.MatchCollection pMatches =
System.Text.RegularExpressions.Regex.Matches(strText, strRegex,
System.Text.RegularExpressions.RegexOptions.ExplicitCapture);
foreach (System.Text.RegularExpressions.Match pMatch in pMatches)
{
System.Text.RegularExpressions.Group pGroup = pMatch.Groups["word"];
string strValue = pGroup.Value;
}

Use the following:

\s*(??<word>"[^"]*")|(?<!")(?<word>[^,"]*)(?<!"))\s*

Rather than splitting, it captures all of the elements without the
commas (and spaces) between them. The way it works is this:

It uses a non-capturing group to indicate that either of the two
choices may be preceded and followed by 0 or more spaces. This
eliminates preceding and following spaces from the groups.

It will capture one of two options:

A quote followed by any sequence of characters that is not a quote,
followed by a quote.
Any sequence of characters that is NOT preceded by a quote and does
not
contain either quotes or commas, and is NOT followed by a quote.
The group "word" will give you all the matches that you want.

-- HTH,

Kevin Spencer
Chicken Salad Surgeon
Microsoft MVP

I created a regular expression to parse a line in a csv file;

(\"(?<word>[^\"]+|\"\")*\"|(?<word>[^,]*))

It is capable of taking a line such as field1,field2,field
3,123.12,"1,234.56" and matching each value between the commas into
the
word group, so I get
field1
field2
field 3
123.12
1,234.56
My problem is that if I perform a split, or match on a string like
1,1,"123.345" I will get 6 matches back instead of 3.

const string strDelimiter =
"(\\\"(?<word>[^\\\"]+|\\\"\\\")*\\\"|(?<word>[^,]*))";
string strText = "1,1,\"12,212.43\"";
string[] strParts =
System.Text.RegularExpressions.Regex.Split(strText ,
strDelimiter,System.Text.RegularExpressions.RegexOptions.Compiled |
System.Text.RegularExpressions.RegexOptions.ExplicitCapture);
System.Text.RegularExpressions.MatchCollection pMatches =
System.Text.RegularExpressions.Regex.Matches(strText ,
strDelimiter,System.Text.RegularExpressions.RegexOptions.ExplicitCa
pture);
Split returns 13 values, as shown below, and Matches returns 6
items.
How can I just extract the 3 items?
strParts {Dimensions:[13]} string[]
[0] "" string
[1] "1" string
[2] "" string
[3] "" string
[4] "," string
[5] "1" string
[6] "" string
[7] "" string
[8] "," string
[9] "30,478.50" string
[10] "" string
[11] "" string
[12] "" string

 

[Jeremy]

I came into a problem though, that if I was parsing a line such as
"1",4,"32,760.00",,23 I would miss one of the values because it was empty,
if I test for 0 length.

I don't know why it does. It has something to do with the internal rules of
the .Net Regex engine. But all you have to do is check for a 0 Length on
each match.

--
HTH,

Kevin Spencer
Chicken Salad Surgeon
Microsoft MVP

Thanks for the regex.

If you perform a match, you will still get 5 matches though on text such
as
1,4,"32,760.00"
You will get "1", "", "4", "", "32.760.00"


I don't understand why it returns 2 empty strings.. any ideas?

Code:

System.Text.RegularExpressions.MatchCollection pMatches =
System.Text.RegularExpressions.Regex.Matches(strText, strRegex,
System.Text.RegularExpressions.RegexOptions.ExplicitCapture);
foreach (System.Text.RegularExpressions.Match pMatch in pMatches)
{
System.Text.RegularExpressions.Group pGroup = pMatch.Groups["word"];
string strValue = pGroup.Value;
}

Use the following:

\s*(??<word>"[^"]*")|(?<!")(?<word>[^,"]*)(?<!"))\s*

Rather than splitting, it captures all of the elements without the
commas (and spaces) between them. The way it works is this:

It uses a non-capturing group to indicate that either of the two choices
may be preceded and followed by 0 or more spaces. This eliminates
preceding and following spaces from the groups.

It will capture one of two options:

A quote followed by any sequence of characters that is not a quote,
followed by a quote.
Any sequence of characters that is NOT preceded by a quote and does not
contain either quotes or commas, and is NOT followed by a quote.

The group "word" will give you all the matches that you want.

--
HTH,

Kevin Spencer
Chicken Salad Surgeon
Microsoft MVP

I created a regular expression to parse a line in a csv file;

(\"(?<word>[^\"]+|\"\")*\"|(?<word>[^,]*))

It is capable of taking a line such as field1,field2,field
3,123.12,"1,234.56" and matching each value between the commas into the
word group, so I get
field1
field2
field 3
123.12
1,234.56

My problem is that if I perform a split, or match on a string like
1,1,"123.345" I will get 6 matches back instead of 3.

const string strDelimiter =
"(\\\"(?<word>[^\\\"]+|\\\"\\\")*\\\"|(?<word>[^,]*))";
string strText = "1,1,\"12,212.43\"";
string[] strParts = System.Text.RegularExpressions.Regex.Split(strText
, strDelimiter,System.Text.RegularExpressions.RegexOptions.Compiled |
System.Text.RegularExpressions.RegexOptions.ExplicitCapture);

System.Text.RegularExpressions.MatchCollection pMatches =
System.Text.RegularExpressions.Regex.Matches(strText ,
strDelimiter,System.Text.RegularExpressions.RegexOptions.ExplicitCapture);
Split returns 13 values, as shown below, and Matches returns 6 items.
How can I just extract the 3 items?

strParts {Dimensions:[13]} string[]
[0] "" string
[1] "1" string
[2] "" string
[3] "" string
[4] "," string
[5] "1" string
[6] "" string
[7] "" string
[8] "," string
[9] "30,478.50" string
[10] "" string
[11] "" string
[12] "" string

 

[Jeremy]

Ahhhhhh! Ok. Thanks, still tring to wrap my head around Regex.

Hello Jeremy,

Thanks for the regex.

If you perform a match, you will still get 5 matches though on text
such as
1,4,"32,760.00"
You will get "1", "", "4", "", "32.760.00"
I don't understand why it returns 2 empty strings.. any ideas?

Basically because if you remove everything that is optional in the regex
below you end up with an empty regex:


\s*(??<word>"[^"]*")|(?<!")(?<word>[^,"]*)(?<!"))\s*

\s* is optional
(??<word>"[^"]*")|(?<!")(?<word>[^,"]*)(?<!")) is optional because one
of the parts of the alteration (namely (?<!")(?<word>[^,"]*)(?<!") is
optional)
\s* is optional

So the regex engine will try to match on every character in the string:
1 stop, first match is found
, comma doesn't match, but the nothingness behind it does.
4 stop, third match is found
, comma doesn't match, but the nothingness behind it does.
"32,760.00" and the last match is found.

You can ueasily demonstrate this by replacing instead of matching. Replace
the matches with something like $ and all the places where a match are
found are visible:

using the above regex and $$ as replacement pattern you will get the
following result:


The issue can be solved in two ways:

1) make sure there are no optional parts:
\s*(??<word>"[^"]*")|(?<!")(?<word>[^,"]+)(?<!"))\s*

2) match the content of what you want to match even more closely within
the pattern of beginnign of the line, comma separated values, end of the
line:
(?<=^|,)\s*("(?<word>[^"]*)"|(?<word>[^",]*?))\s*(?=,|$)
This last regex also removes any whitespace around the non quoted values
and removes the quotes from quoted values.

Jesse

Code:

System.Text.RegularExpressions.MatchCollection pMatches =
System.Text.RegularExpressions.Regex.Matches(strText, strRegex,
System.Text.RegularExpressions.RegexOptions.ExplicitCapture);
foreach (System.Text.RegularExpressions.Match pMatch in pMatches)
{
System.Text.RegularExpressions.Group pGroup =
pMatch.Groups["word"];
string strValue = pGroup.Value;
}

Use the following:

\s*(??<word>"[^"]*")|(?<!")(?<word>[^,"]*)(?<!"))\s*

Rather than splitting, it captures all of the elements without the
commas (and spaces) between them. The way it works is this:

It uses a non-capturing group to indicate that either of the two
choices may be preceded and followed by 0 or more spaces. This
eliminates preceding and following spaces from the groups.

It will capture one of two options:

A quote followed by any sequence of characters that is not a quote,
followed by a quote.
Any sequence of characters that is NOT preceded by a quote and does
not
contain either quotes or commas, and is NOT followed by a quote.
The group "word" will give you all the matches that you want.

-- HTH,

Kevin Spencer
Chicken Salad Surgeon
Microsoft MVP

I created a regular expression to parse a line in a csv file;

(\"(?<word>[^\"]+|\"\")*\"|(?<word>[^,]*))

It is capable of taking a line such as field1,field2,field
3,123.12,"1,234.56" and matching each value between the commas into
the
word group, so I get
field1
field2
field 3
123.12
1,234.56
My problem is that if I perform a split, or match on a string like
1,1,"123.345" I will get 6 matches back instead of 3.

const string strDelimiter =
"(\\\"(?<word>[^\\\"]+|\\\"\\\")*\\\"|(?<word>[^,]*))";
string strText = "1,1,\"12,212.43\"";
string[] strParts =
System.Text.RegularExpressions.Regex.Split(strText ,
strDelimiter,System.Text.RegularExpressions.RegexOptions.Compiled |
System.Text.RegularExpressions.RegexOptions.ExplicitCapture);
System.Text.RegularExpressions.MatchCollection pMatches =
System.Text.RegularExpressions.Regex.Matches(strText ,
strDelimiter,System.Text.RegularExpressions.RegexOptions.ExplicitCap
ture);
Split returns 13 values, as shown below, and Matches returns 6
items.
How can I just extract the 3 items?
strParts {Dimensions:[13]} string[]
[0] "" string
[1] "1" string
[2] "" string
[3] "" string
[4] "," string
[5] "1" string
[6] "" string
[7] "" string
[8] "," string
[9] "30,478.50" string
[10] "" string
[11] "" string
[12] "" string

 

[Jesse Houwing]

Hello Jeremy,

Ahhhhhh! Ok. Thanks, still tring to wrap my head around Regex.

The fact that you really need to know how the engine works, to explain some
strange behaviour isn't helping with that usually . keep wrapping your
head. It'll get easier over time.

Until that, don't hesitate to keep asking questions.

Jesse

Hello Jeremy,

Thanks for the regex.

If you perform a match, you will still get 5 matches though on text
such as
1,4,"32,760.00"
You will get "1", "", "4", "", "32.760.00"
I don't understand why it returns 2 empty strings.. any ideas?

Basically because if you remove everything that is optional in the
regex below you end up with an empty regex:

\s*(??<word>"[^"]*")|(?<!")(?<word>[^,"]*)(?<!"))\s*

\s* is optional
(??<word>"[^"]*")|(?<!")(?<word>[^,"]*)(?<!")) is optional because
one
of the parts of the alteration (namely (?<!")(?<word>[^,"]*)(?<!") is
optional)
\s* is optional
So the regex engine will try to match on every character in the
string:
1 stop, first match is found
, comma doesn't match, but the nothingness behind it does.
4 stop, third match is found
, comma doesn't match, but the nothingness behind it does.
"32,760.00" and the last match is found.
You can ueasily demonstrate this by replacing instead of matching.
Replace the matches with something like $ and all the places where a
match are found are visible:

using the above regex and $$ as replacement pattern you will get the
following result:

The issue can be solved in two ways:

1) make sure there are no optional parts:
\s*(??<word>"[^"]*")|(?<!")(?<word>[^,"]+)(?<!"))\s*
2) match the content of what you want to match even more closely
within
the pattern of beginnign of the line, comma separated values, end of
the
line:
(?<=^|,)\s*("(?<word>[^"]*)"|(?<word>[^",]*?))\s*(?=,|$)
This last regex also removes any whitespace around the non quoted
values
and removes the quotes from quoted values.
Jesse

Code:

System.Text.RegularExpressions.MatchCollection pMatches =
System.Text.RegularExpressions.Regex.Matches(strText, strRegex,
System.Text.RegularExpressions.RegexOptions.ExplicitCapture);
foreach (System.Text.RegularExpressions.Match pMatch in pMatches)
{
System.Text.RegularExpressions.Group pGroup =
pMatch.Groups["word"];
string strValue = pGroup.Value;
}
Use the following:

\s*(??<word>"[^"]*")|(?<!")(?<word>[^,"]*)(?<!"))\s*

Rather than splitting, it captures all of the elements without the
commas (and spaces) between them. The way it works is this:

It uses a non-capturing group to indicate that either of the two
choices may be preceded and followed by 0 or more spaces. This
eliminates preceding and following spaces from the groups.

It will capture one of two options:

A quote followed by any sequence of characters that is not a quote,
followed by a quote.
Any sequence of characters that is NOT preceded by a quote and does
not
contain either quotes or commas, and is NOT followed by a quote.
The group "word" will give you all the matches that you want.
-- HTH,

Kevin Spencer
Chicken Salad Surgeon
Microsoft MVP
I created a regular expression to parse a line in a csv file;

(\"(?<word>[^\"]+|\"\")*\"|(?<word>[^,]*))

It is capable of taking a line such as field1,field2,field
3,123.12,"1,234.56" and matching each value between the commas
into
the
word group, so I get
field1
field2
field 3
123.12
1,234.56
My problem is that if I perform a split, or match on a string like
1,1,"123.345" I will get 6 matches back instead of 3.
const string strDelimiter =
"(\\\"(?<word>[^\\\"]+|\\\"\\\")*\\\"|(?<word>[^,]*))";
string strText = "1,1,\"12,212.43\"";
string[] strParts =
System.Text.RegularExpressions.Regex.Split(strText ,
strDelimiter,System.Text.RegularExpressions.RegexOptions.Compiled
|
System.Text.RegularExpressions.RegexOptions.ExplicitCapture);
System.Text.RegularExpressions.MatchCollection pMatches =
System.Text.RegularExpressions.Regex.Matches(strText ,
strDelimiter,System.Text.RegularExpressions.RegexOptions.ExplicitC
ap
ture);
Split returns 13 values, as shown below, and Matches returns 6
items.
How can I just extract the 3 items?
strParts {Dimensions:[13]} string[]
[0] "" string
[1] "1" string
[2] "" string
[3] "" string
[4] "," string
[5] "1" string
[6] "" string
[7] "" string
[8] "," string
[9] "30,478.50" string
[10] "" string
[11] "" string
[12] "" string

 

[Kevin Spencer]

Yes, Jesse is the master when it comes to regular expressions. I can do
pretty well with them, but he knows the engine inside and out.

--
HTH,

Kevin Spencer
Chicken Salad Surgeon
Microsoft MVP

Ahhhhhh! Ok. Thanks, still tring to wrap my head around Regex.

Hello Jeremy,

Thanks for the regex.

If you perform a match, you will still get 5 matches though on text
such as
1,4,"32,760.00"
You will get "1", "", "4", "", "32.760.00"
I don't understand why it returns 2 empty strings.. any ideas?

Basically because if you remove everything that is optional in the regex
below you end up with an empty regex:


\s*(??<word>"[^"]*")|(?<!")(?<word>[^,"]*)(?<!"))\s*

\s* is optional
(??<word>"[^"]*")|(?<!")(?<word>[^,"]*)(?<!")) is optional because one
of the parts of the alteration (namely (?<!")(?<word>[^,"]*)(?<!") is
optional)
\s* is optional

So the regex engine will try to match on every character in the string:
1 stop, first match is found
, comma doesn't match, but the nothingness behind it does.
4 stop, third match is found
, comma doesn't match, but the nothingness behind it does.
"32,760.00" and the last match is found.

You can ueasily demonstrate this by replacing instead of matching.
Replace the matches with something like $ and all the places where a
match are found are visible:

using the above regex and $$ as replacement pattern you will get the
following result:


The issue can be solved in two ways:

1) make sure there are no optional parts:
\s*(??<word>"[^"]*")|(?<!")(?<word>[^,"]+)(?<!"))\s*

2) match the content of what you want to match even more closely within
the pattern of beginnign of the line, comma separated values, end of the
line:
(?<=^|,)\s*("(?<word>[^"]*)"|(?<word>[^",]*?))\s*(?=,|$)
This last regex also removes any whitespace around the non quoted values
and removes the quotes from quoted values.

Jesse

Code:

System.Text.RegularExpressions.MatchCollection pMatches =
System.Text.RegularExpressions.Regex.Matches(strText, strRegex,
System.Text.RegularExpressions.RegexOptions.ExplicitCapture);
foreach (System.Text.RegularExpressions.Match pMatch in pMatches)
{
System.Text.RegularExpressions.Group pGroup =
pMatch.Groups["word"];
string strValue = pGroup.Value;
}

Use the following:

\s*(??<word>"[^"]*")|(?<!")(?<word>[^,"]*)(?<!"))\s*

Rather than splitting, it captures all of the elements without the
commas (and spaces) between them. The way it works is this:

It uses a non-capturing group to indicate that either of the two
choices may be preceded and followed by 0 or more spaces. This
eliminates preceding and following spaces from the groups.

It will capture one of two options:

A quote followed by any sequence of characters that is not a quote,
followed by a quote.
Any sequence of characters that is NOT preceded by a quote and does
not
contain either quotes or commas, and is NOT followed by a quote.
The group "word" will give you all the matches that you want.

-- HTH,

Kevin Spencer
Chicken Salad Surgeon
Microsoft MVP

I created a regular expression to parse a line in a csv file;

(\"(?<word>[^\"]+|\"\")*\"|(?<word>[^,]*))

It is capable of taking a line such as field1,field2,field
3,123.12,"1,234.56" and matching each value between the commas into
the
word group, so I get
field1
field2
field 3
123.12
1,234.56
My problem is that if I perform a split, or match on a string like
1,1,"123.345" I will get 6 matches back instead of 3.

const string strDelimiter =
"(\\\"(?<word>[^\\\"]+|\\\"\\\")*\\\"|(?<word>[^,]*))";
string strText = "1,1,\"12,212.43\"";
string[] strParts =
System.Text.RegularExpressions.Regex.Split(strText ,
strDelimiter,System.Text.RegularExpressions.RegexOptions.Compiled |
System.Text.RegularExpressions.RegexOptions.ExplicitCapture);
System.Text.RegularExpressions.MatchCollection pMatches =
System.Text.RegularExpressions.Regex.Matches(strText ,
strDelimiter,System.Text.RegularExpressions.RegexOptions.ExplicitCap
ture);
Split returns 13 values, as shown below, and Matches returns 6
items.
How can I just extract the 3 items?
strParts {Dimensions:[13]} string[]
[0] "" string
[1] "1" string
[2] "" string
[3] "" string
[4] "," string
[5] "1" string
[6] "" string
[7] "" string
[8] "," string
[9] "30,478.50" string
[10] "" string
[11] "" string
[12] "" string