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This homework assignment requires the knowledge from Module 3.
 
This homework assignment requires the knowledge from Module 3.
  
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=== Please write a regular expression for matching the sequence of hostnames and optional port specifications which follows these rules: ===
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==== Please write a regular expression for matching the sequence of numbers which follows these rules: ====
  
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# The sequence consists of one or more parts. If there are two or more parts, they are separated with a comma (",") character.
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* The sequence consists of one or more parts. If there are two or more parts, they are separated with a comma (",") character.
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# Each part of the sequence is a hostname which must consist of letters only, with optional port specifications following the hostname. If port specifications are present, each specification is preceded by a single colon (":") character. A valid specification consists of decimal digits that define the port number, and port number may be followed by either "/tcp" or "/udp" suffix (other suffixes are not allowed).
 
  
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Additional remark -- it is not mandatory to verify that port number falls into range 1..65535.
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* Each part of the sequence is either an integer or a real number. An integer number consists of one or more digits and must not begin with zero ("0"), unless the integer number has only one digit. If the part of the sequence is a real number, it consists of one or more digits which are followed by one dot (".") character, with this dot character being followed by one or more digits. Like the integer number, the real number must not begin with zero ("0"), unless there is only one digit before the dot character. Also, the real number must not end with zero ("0"), unless there is only one digit after the dot character.
  
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Please note that for accomplishing the task, one regular expression has to be submitted which is '''suitable for use with the ''egrep'' or ''pcregrep'' tool'''. It is not acceptable to submit the solution in a fragmented way (e.g., several isolated expressions for addressing different parts of the task). Also, it is not allowed to submit programs in Java, Python, Perl (or any other language) for the solution.
 
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'''Finally, if the solution only works with the examples provided below but does NOT meet the task specification, it will be treated as incorrect.'''
 
  
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=== Examples of sequences the regular expression must match: ===
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Please note that for accomplishing the task, '''one regular expression''' has to be submitted which is '''suitable for use with the egrep or pcre2grep tool'''.
 +
It is not acceptable to submit the solution in a fragmented way (e.g.,several isolated expressions for addressing different parts of the task).
 +
Also, it is not allowed to submit programs in Java, Python, Perl (or any other language) for the solution.
  
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myhost:123:22/tcp
 
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(the sequence has one valid part -- a hostname with two port specifications)
 
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dbserver:161/udp:80,mailserver:25/tcp
 
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(the sequence has two valid parts)
 
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fileserver:2049:22/tcp:8080,mailserver:443/tcp:22/tcp:123/udp,myhost
 
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(the sequence has three valid parts, with the first and second parts having port specifications)
 
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serverA,serverB,serverC:20:21:22:23:25,serverD,serverE
 
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(the sequence has five valid parts, where only the third hostname has port numbers)
 
  
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=== Examples of sequences the regular expression must NOT match: ===
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==== Examples of sequences the regular expression must match: ====
  
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  serverA, serverB:80
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  12345                (the sequence has one valid integer part)
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  (the second part begins with a space character which is illegal)  
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915,2.35            (the sequence has two valid parts - an integer
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  serverA 22,myhost
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                      and a real number)
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(the first part contains a space character which is illegal)  
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1.205,754.0          (the sequence has two valid real number parts)
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  myhost:80,
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(the first part ends with comma, but there is no following second part)  
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8.4,12,0.1          (the sequence has three valid parts - a real number,
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                      integer, and a real number)
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myhost6
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  (the hostname contains an illegal character 6)  
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1,1.0,3,4.8,0.0,0,7.001,8.0      (the sequence has eight valid parts)
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+
 
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myhost:9A
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  (the port number contains an illegal character A)  
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==== Examples of sequences the regular expression must NOT match: ====
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+
 
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myhost::80
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  1, 2          (the second part begins with a space character which is illegal)
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  (two colons precede the port number)
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  1 2,3        (the first part contains a space character which is illegal)
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myhost:80/
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(port number is followed by /, but there is no transport protocol string)  
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  9.0,         (the first part ends with comma, but there is no
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                following second part)
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server:80tcp
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  (there is no separating / character between port number and transport protocol string)
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  9F            (the number contains an illegal character F)
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+
 
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  serverA,,serverC
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  02            (the integer number has more than one digit and begins with
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(the second part of the sequence is empty)  
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                a zero which is illegal)
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+
 
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  !"serverA:121,myhost,serverB:22
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  2.00          (the real number has more than one digit after the dot character
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  (the sequence begins with illegal characters)  
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                and ends with a zero which is illegal)
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+
 
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serverA:80,myhost:312/tcp+T
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  2-1          (the number contains an illegal character -)
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  (the sequence ends with illegal characters)
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 +
  2,,8.9        (the second part of the sequence is empty)
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 +
  2.            (the real number contains a dot character without at least
 +
                one following digit)
 +
 
 +
  .3            (the real number contains a dot character without at least
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                one preceding digit)
 +
 
 +
  1.43.222      (the real number illegally contains two dot characters)

Viimane redaktsioon: 26. september 2023, kell 12:18

This homework assignment requires the knowledge from Module 3.

Please write a regular expression for matching the sequence of numbers which follows these rules:

  • The sequence consists of one or more parts. If there are two or more parts, they are separated with a comma (",") character.
  • Each part of the sequence is either an integer or a real number. An integer number consists of one or more digits and must not begin with zero ("0"), unless the integer number has only one digit. If the part of the sequence is a real number, it consists of one or more digits which are followed by one dot (".") character, with this dot character being followed by one or more digits. Like the integer number, the real number must not begin with zero ("0"), unless there is only one digit before the dot character. Also, the real number must not end with zero ("0"), unless there is only one digit after the dot character.


Please note that for accomplishing the task, one regular expression has to be submitted which is suitable for use with the egrep or pcre2grep tool. It is not acceptable to submit the solution in a fragmented way (e.g.,several isolated expressions for addressing different parts of the task). Also, it is not allowed to submit programs in Java, Python, Perl (or any other language) for the solution.


Examples of sequences the regular expression must match:

12345                (the sequence has one valid integer part)

915,2.35             (the sequence has two valid parts - an integer 
                      and a real number)

1.205,754.0          (the sequence has two valid real number parts)

8.4,12,0.1           (the sequence has three valid parts - a real number, 
                      integer, and a real number)

1,1.0,3,4.8,0.0,0,7.001,8.0      (the sequence has eight valid parts)


Examples of sequences the regular expression must NOT match:

1, 2          (the second part begins with a space character which is illegal)

1 2,3         (the first part contains a space character which is illegal)

9.0,          (the first part ends with comma, but there is no
               following second part)

9F            (the number contains an illegal character F)

02            (the integer number has more than one digit and begins with 
               a zero which is illegal)

2.00          (the real number has more than one digit after the dot character 
               and ends with a zero which is illegal)

2-1           (the number contains an illegal character -)

2,,8.9        (the second part of the sequence is empty)

2.            (the real number contains a dot character without at least
               one following digit)

.3            (the real number contains a dot character without at least
               one preceding digit)

1.43.222      (the real number illegally contains two dot characters)
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