Match expressions separated by spaces

Question

I have the following line:

1 2/5 0.4 1+3i

Each group can be separated by one or more spaces. The first one, can have spaces or not before him. The last one can have spaces or not after him.

I want to get:

1
2/5
0.4
1+3i

How can I get them with regex? To be simple I tried on a shorter example because complex is the more difficult:

2 3i

I tried with the following regex:

/\s*((?:[\d]+)|(?:[\d]*\i))/g

But I get the i separated from its integer:

2
3
i

I can't find a good regex for my problem. Any solution?

Duplicate :- http://stackoverflow.com/questions/225337/how-do-i-split-a-string-with-any-whitespace-chars-as-delimiters — rock321987, May 24 '16 at 16:58
I am using C++. I'm not looking just for separating string surrounded by spaces. I'm only looking for integers, fractionnal and complex numbers separated by spaces. So not everything — Sylvain M, May 24 '16 at 17:03
in that case you can use match :- **[like](https://regex101.com/r/dH1dZ4/3)** — rock321987, May 24 '16 at 17:09
Okay @rock321987 your solution is actually working fine. But I would like to catch complex numbers without real part, like this: `4i` or just `i`. I'm not very friendly with regex, I tried to edit your solution but failed. Could you please help me a bit more for that? Thanks — Sylvain M, May 24 '16 at 17:25
For sure ahah, no prob' @rock321987, take your time & thanks in advance — Sylvain M, May 24 '16 at 17:33

rock321987 · Accepted Answer · 2016-05-24T18:01:26.337

2

You can use match instead of split like

((?:\d+(?:\.\d+)?)\/(?:\d+(?:\.\d+)?))|((?:[+-]?\d+(?:\.\d+)?)?[+-]?(?:\d+(?:\.\d+)?)?i)|([+-]?\d+(?:\.\d+)?)

Regex Breakdown

((?:\d+(?:\.\d+)?)\/(?:\d+(?:\.\d+)?)) #For fractional part
  |
((?:[+-]?\d+(?:\.\d+)?)?[+-]?(?:\d+(?:\.\d+)?)?i) #For complex number
  |
([+-]?\d+(?:\.\d+)?) #For any numbers

Further Breakdown

(
   (?:\d+(?:\.\d+)?) #Match any number with or without decimal
     \/ #Match / literally
   (?:\d+(?:\.\d+)?) #Match any number with or without decimal
) #For fractional part

| #Alternation(OR)

(
   (?:[+-]?\d+(?:\.\d+)?) #Match real part of the number
   ? #This makes real part optional
   [+-]? #Match + or - and make it optional for cases like \di
   (?:\d+(?:\.\d+)?)? #Match the digits of imaginary part (optional if we want to match only i)
   i #Match i
) #For complex number

| #Alternation(OR)

([+-]?\d+(?:\.\d+)?) #Match any numbers with or without decimal

Regex Demo

edited May 24 '16 at 18:01

answered May 24 '16 at 17:51

rock321987

10,942
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Wow really nice answer! Thanks a lot! One last thing: how is it possible to match fractional in the real and imaginary part of a complex? – Sylvain M May 24 '16 at 19:12
@SylvainM just take care not to put the last term of alternation `([+-]?\d+(?:\.\d+)?)` to starting or middle..otherwise it will be wrong.. – rock321987 May 24 '16 at 19:15
@SylvainM can you give an example? – rock321987 May 24 '16 at 19:16
Okay! I would like to match something like `1/2+2/3i` with `1/2` the real part and `3/2` the imaginary one, in addition to the current features of the version you gave. – Sylvain M May 24 '16 at 19:28
@SylvainM so it can be `1i/2+2/3i`? – rock321987 May 24 '16 at 19:35
No, it must be `a+bi` where `a` and `b` can be integer/real or fractional like `x/y`. But not the form `ai/b` or something like that. – Sylvain M May 24 '16 at 19:42
@SylvainM glad to help..enjoy – rock321987 May 24 '16 at 19:49

Match expressions separated by spaces

1 Answers1