I have a string such this that described a structured data source:
Header whocares;
SampleTestPlan 2
a b
c d;
Test abc;
SampleTestPlan 3
e f
g h
i l;
Wafer 01;
EndOfFile;
Every field...
... is starting with "FieldName"
... is ending with ";"
... may contain linefeed
My need is to find with regular expression the values of SampleTestPlan that's repeated twice. So...
1st value is:
2
a b
c d
2nd value is
3
e f
g h
i l
I've performed several attempts with such search string:
/SampleTestPlan(.\s)/gm
/SampleTestPlan(.\s);/gm
/SampleTestPlan(.*);/gm
but I need to understand much better how Regular Expression work as I'm definitively a newbie on them and I need to learn a lot.
Thanks in advance to anyone that may help me!
Stefano, Milan, ITALY
You could use the following regex:
(?<=\w\b)[^;]+(?=;)
See it working live here on regex101!
How it works:
It matches everything that is:
preceded by a sequence of characters: \w+
followed by a ;
contains anything (at least one character) except a ; (including newlines).
For example, for that input:
Header whocares;
SampleTestPlan 2
a b
c d;
Test abc;
SampleTestPlan 3
e f
g h
i l;
Wafer 01;
EndOfFile;
It matches 5 times:
whocares
then:
2
a b
c d
then:
abc
then:
3
e f
g h
i l
then:
01
Assuming your input will be always in this well formatted like the sample, try this:
/SampleTestPlan(\s+\d+.*?);/sg
Here, /s modifier means Dot matches newline characters
You can try this at online.
That would be /SameTestPlan([^;]+)/g. [^abc] means any character which is not a, b or c.
Related
Let H be column 1, E be column 2, L column 3, P 4
I understand where the H comes from.
I also see how the L works.
But I am a bit confused on E and P.
If we look horizontally, the regex HE|LL|0+ only matches {HE, LL, 0 (1 or more times)}
The regex EP|IP|EF matches {EP, IP, EF}
How is it that the string E matches both of these conditions?
Similarly with [PLEASE], which matches {P, L, E, A, S, E} (any combination of these letters), only matches with EP from the vertical regex, then why is there just a P?
Am I reading this incorrectly? This was taken from regexcrossword
I think you misunderstand the nature of the crossword.
The string HE matches HE|LL|O+
The string LP matches [PLEASE]+
The string HL matches [^SPEAK]+
The string EP matches EP|IF|EF
Each row and column matches its regex, so the solution is valid.
Like, the following statement doesn't make sense...
How is it that the string E matches both of these conditions?
There is no string E. There are two strings, HE and EP.
I can do this with two separate regex passes, but this is already slow and doing two doesn't help, so I want to be able to do it in one pass.
I want to:
replace multiple spaces with one space
replace a dash (hyphen) with a space
However, if the dash has a space on either side of it then the dash and any spaces either side to be replaced with just one space.
As an example:
a - b c-d e -f g- h i - j k - l m - n
must end up like
a b c d e f g h i j k l m n
I have tried things like this:
\s+| - | -|- |-
but that doesn't work:
a b c d e f g h i j k l m n
Use the following regexp to match multiple spaces or dashes;
[\s-]+
Replace with a single space.
[\s-]+ with a global 'g' modifier and replace with one single space.
See here
Regex:
(?:\s*-\s*)+|\s{2,}
REplacement string:
<space>
DEMO
I'm a newbie to Lua. And I want to parse the text like
Phase1:A B Phase2:A B Phase3:W O R D Phase4:WORD
to
Phase1 Phase2 Phase3 Phase4
A A B W O R D WORD
I used string.gmatch(s, "(%w+):(%w+)"), I can only get
Phase1 Phase2 Phase3 Phase4
A A W WORD
How can I get missing B, O, R, D back?
Or do I need to write pattern for every phases? How to do that?
The input text in your example doesn't have any clear delimiter between the phrases so parsing it accurately with regex is tricky.
This would be much easier to parse if you add a delimiter symbol like a , to separate the phrases.
Phrase1:A B, Phrase2:A B, Phrase3:W O R D,Phrase4:WORD
You can then parse it with this pattern:
s = "Phrase1:A B, Phrase2:A B, Phrase3:W O R D,Phrase4:WORD"
for k, v in s:gmatch "(Phrase%d+):([^,]+)" do
print(k, v)
end
outputs:
Phrase1 A B
Phrase2 A B
Phrase3 W O R D
Phrase4 WORD
If it's not possible to relax the above constraint, you can try this pattern:
s:gmatch "Phrase%d+:%w[%w ]* "
Note there's a caveat with this pattern, the string you're parsing needs to have an extra space at the end or the last phrase won't get parsed.
for k, v in s:gsub('%s*(%w+:)','\0%1'):gmatch'%z(%w+):(%Z*)'
– #Egor Skriptunoff
This pattern works better.
I have a string 00000001001300000708303939313833313932E2
so, I want to match everything between 708 & E2..
So I wrote:
(?<=708)(.*\n?)(?=E2) - tested in RegExr (it's working)
Now, from that result 303939313833313932 match to get result
(every second number):
099183192
How ?
To match everything between 708 and E2, use:
708(\d+)
if you are sure that there will be only digits. Otherwise try with:
708(.*?)E2
To match every second digit from 303939313833313932, use:
(?:\d(\d))+
use a global replace:
find: \d(\d)
replace: $1
Are you expecting a regular expression answer to this?
You are perhaps better off doing this using string operations in whatever programming language you're using. If you have text = "abcdefghi..." then do output = text[0] + text[2] + text[4]... in a loop, until you run out of characters.
You haven't specified a programming language, but in Python I would do something like:
>>> text = "abcdefghjiklmnop"
>>> for n, char in enumerate(text):
... if n % 2 == 0: #every second char
... print char
...
a
c
e
g
j
k
m
o
In another question I learned how to calculate straight poker hand using regex (here).
Now, by curiosity, the question is: can I use regex to calculate the same thing, using ASCII CODE?
Something like:
regex: [C][C+1][C+2][C+3][C+4], being C the ASCII CODE (or like this)
Matches: 45678, 23456
Doesn't matches: 45679 or 23459 (not in sequence)
Your main problem is really going to be that you're not using ASCII-consecutive encodings for your hands, you're using numerics for non-face cards, and non-consecutive, non-ordered characters for face cards.
You need to detect, at the start of the strings, 2345A, 23456, 34567, ..., 6789T, 789TJ, 89TJQ, 9TJQK and TJQKA.
These are not consecutive ASCII codes and, even if they were, you would run into problems since both A2345 and TJQKA are valid and you won't get A being both less than and greater than the other characters in the same character set.
If it has to be done by a regex, then the following regex segment:
(2345A|23456|34567|45678|56789|6789T|789TJ|89TJQ|9TJQK|TJQKA)
is probably the easiest and most readable one you'll get.
There is no regex that will do what you want as the other answers have pointed out, but you did say that you want to learn regex, so here's another meta-regex approach that may be instructional.
Here's a Java snippet that, given a string, programmatically generate the pattern that will match any substring of that string of length 5.
String seq = "ABCDEFGHIJKLMNOP";
System.out.printf("^(%s)$",
seq.replaceAll(
"(?=(.{5}).).",
"$1|"
)
);
The output is (as seen on ideone.com):
^(ABCDE|BCDEF|CDEFG|DEFGH|EFGHI|FGHIJ|GHIJK|HIJKL|IJKLM|JKLMN|KLMNO|LMNOP)$
You can use this to conveniently generate the regex pattern to match straight poker hands, by initializing seq as appropriate.
How it works
. metacharacter matches "any" character (line separators may be an exception depending on the mode we're in).
The {5} is an exact repetition specifier. .{5} matches exactly 5 ..
(?=…) is positive lookahead; it asserts that a given pattern can be matched, but since it's only an assertion, it doesn't actually make (i.e. consume) the match from the input string.
Simply (…) is a capturing group. It creates a backreference that you can use perhaps later in the pattern, or in substitutions, or however you see fit.
The pattern is repeated here for convenience:
match one char
at a time
|
(?=(.{5}).).
\_________/
must be able to see 6 chars ahead
(capture the first 5)
The pattern works by matching one character . at a time. Before that character is matched, however, we assert (?=…) that we can see a total of 6 characters ahead (.{5})., capturing (…) into group 1 the first .{5}. For every such match, we replace with $1|, that is, whatever was captured by group 1, followed by the alternation metacharacter.
Let's consider what happens when we apply this to a shorter String seq = "ABCDEFG";. The ↑ denotes our current position.
=== INPUT === === OUTPUT ===
A B C D E F G ABCDE|BCDEFG
↑
We can assert (?=(.{5}).), matching ABCDEF
in the lookahead. ABCDE is captured.
We now match A, and replace with ABCDE|
A B C D E F G ABCDE|BCDEF|CDEFG
↑
We can assert (?=(.{5}).), matching BCDEFG
in the lookahead. BCDEF is captured.
We now match B, and replace with BCDEF|
A B C D E F G ABCDE|BCDEF|CDEFG
↑
Can't assert (?=(.{5}).), skip forward
A B C D E F G ABCDE|BCDEF|CDEFG
↑
Can't assert (?=(.{5}).), skip forward
A B C D E F G ABCDE|BCDEF|CDEFG
↑
Can't assert (?=(.{5}).), skip forward
:
:
A B C D E F G ABCDE|BCDEF|CDEFG
↑
Can't assert (?=(.{5}).), and we are at
the end of the string, so we're done.
So we get ABCDE|BCDEF|CDEFG, which are all the substrings of length 5 of seq.
References
regular-expressions.info/Dot, Repetition, Grouping, Lookaround
Something like regex: [C][C+1][C+2][C+3][C+4], being C the ASCII CODE (or like this)
You can not do anything remotely close to this in most regex flavors. This is simply not the kinds of patterns that regex is designed for.
There is no mainstream regex pattern that will succintly match any two consecutive characters that differ by x in their ASCII encoding.
For instructional purposes...
Here you go (see also on ideone.com):
String alpha = "ABCDEFGHIJKLMN";
String p = alpha.replaceAll(".(?=(.))", "$0(?=$1|\\$)|") + "$";
System.out.println(p);
// A(?=B|$)|B(?=C|$)|C(?=D|$)|D(?=E|$)|E(?=F|$)|F(?=G|$)|G(?=H|$)|
// H(?=I|$)|I(?=J|$)|J(?=K|$)|K(?=L|$)|L(?=M|$)|M(?=N|$)|N$
String p5 = String.format("(?:%s){5}", p);
String[] tests = {
"ABCDE", // true
"JKLMN", // true
"AAAAA", // false
"ABCDEFGH", // false
"ABCD", // false
"ACEGI", // false
"FGHIJ", // true
};
for (String test : tests) {
System.out.printf("[%s] : %s%n",
test,
test.matches(p5)
);
}
This uses meta-regexing technique to generate a pattern. That pattern ensures that each character is followed by the right character (or the end of the string), using lookahead. That pattern is then meta-regexed to be matched repeatedly 5 times.
You can substitute alpha with your poker sequence as necessary.
Note that this is an ABSOLUTELY IMPRACTICAL solution. It's much more readable to e.g. just check if alpha.contains(test) && (test.length() == 5).
Related questions
How does the regular expression (?<=#)[^#]+(?=#) work?
SOLVED!
See in http://jsfiddle.net/g48K9/3
I solved using closure, in js.
String.prototype.isSequence = function () {
If (this == "A2345") return true; // an exception
return this.replace(/(\w)(\w)(\w)(\w)(\w)/, function (a, g1, g2, g3, g4, g5) {
return code(g1) == code(g2) -1 &&
code(g2) == code(g3) -1 &&
code(g3) == code(g4) -1 &&
code(g4) == code(g5) -1;
})
};
function code(card){
switch(card){
case "T": return 58;
case "J": return 59;
case "Q": return 60;
case "K": return 61;
case "A": return 62;
default: return card.charCodeAt();
}
}
test("23456");
test("23444");
test("789TJ");
test("TJQKA");
test("8JQKA");
function test(cards) {
alert("cards " + cards + ": " + cards.isSequence())
}
Just to clarify, ascii codes:
ASCII CODES:
2 = 50
3 = 51
4 = 52
5 = 53
6 = 54
7 = 55
8 = 56
9 = 57
T = 84 -> 58
J = 74 -> 59
Q = 81 -> 60
K = 75 -> 61
A = 65 -> 62