Function r = tagexponents(s,tag1,tag2)
"tags" the exponents in string s and returns the
result in string r.
The function looks for ordinary computer representations
of real numbers with an exponent by "e", e.g. 1e3
for one thousand.
More precisely in a regex notation, this is the pattern
of the number expression which is searched for:
[-+]{0,1}[0-9]{1,}(.[0-9]{1,}){0,1}[eEdD][-+]{0,1}[0-9]{1,}
So:
-- the number expression always contains an "e",
"E", "d" or "D" between the mantissa and
exponent;
-- the mantissa contains at least one digit;
-- the mantissa may or may not contain a decimal
dot; if it does, there are always digits before
and after the dot;
-- the exponent contains at least one digit.
There may be zero, one or more such number
expressions in input string s. There may also
be other words (letters etc.) in string s.
Multiple number expressions must be separated
from each other and from other words by: spaces,
end-of-line characters \n and \r, tab characters \t,
commas, semicolons, slashes / and \, and brackets
( ) [ ] { } < >.
When an number expression is found, the tags
tag1 and tag2 are inserted. Moreover, plus signs
(of the number and of the exponent) and
non-significant (leading) zeros within exponents
are removed.
E.g.
tagexponents("1.23e+04 5.6e-07 1e8 2e+0","<exp>","</exp>")
returns:
"1.23<exp>4</exp> 5.6<exp>-7</exp> 1<exp>8</exp> 2<exp>0</exp>".
And
tagexponents("array = [+1.23e+005,-23.45e-098,tree3]","<exp>","</exp>")
returns:
"array = [1.23<exp>5</exp>,-23.45<exp>-98</exp>,tree3]".
Issue e.g.
tagexponents(s,"e","")
to get only the removal of plus signs and non-significant
zeros within exponents.
(c) 2026 fabien van mook
2026.08.20 release of this file within package "fvm-miscellaneous" under GNU GPLv3+
