Scientific Prefix to Number

Convert SI-prefixed text (aka engineering / metric prefix) into numeric values. Bonus: binary prefixes!

The function SIP2NUM converts a string with an SI prefix (aka metric prefix, or engineering prefix) into a numeric value. For example the string '1 k' is converted to 1000. The bonus function BIP2NUM converts from Binary-prefixed string to numeric, for example the value '1 Ki' is converted to 1024.

After testing many submissions on MATLAB FEX (see Acknowledgements) and not finding a single one that converted all values correctly, I wrote my own functions. And then exhaustively tested them to confirm that they actually give the correct output.

This submission:

• Automatically detects the prefix, or it may be restricted to either a name or symbol.
• Detects coefficients including +/- sign, decimal digits, and exponent E-notation.
• Detects zero or more coefficients in the string.
• Returns the parts of the input string that are split by the detected coefficients and prefixes.
• Returns the number of significant figures detected in the coefficients.
• Includes the prefixes added in November 2022: ronna, quetta, ronto, and quecto.

Reverse Conversion

http://www.mathworks.com/matlabcentral/fileexchange/33174-number-to-scientific-prefix

SI Prefix Examples

>> sip2num('10 k') % OR sip2num('10.0 kilo') OR sip2num('10000') OR sip2num('1e4')
ans = 10000

>> [num,spl] = sip2num("Power: 200 megawatt")
num = 200000000
spl = ["Power: ","watt"]

>> [num,spl,sgf] = sip2num("from -3.6 MV to +1.24kV potential difference.")
num = [-3600000,1240]
spl = ["from ","V to ","V potential difference."]
sgf = [2,3]

>> [num,spl] = sip2num("100 meter","meter") % Try it without the second option.
num = 100
spl = ["","meter"]

>> sip2num(num2sip(9e12)) % 9 tera == 9e12 == 9*1000^4 == 9000000000000
ans = 9000000000000

Binary Prefix Examples

>> bip2num('10 Ki') % OR bip2num('10.0 kibi') OR bip2num('10240') OR bip2num('1.024e4')
ans = 10240

>> [num,spl] = bip2num("Memory: 200 mebibyte")
num = 209715200
spl = ["Memory: ","byte"]

>> [num,spl,sgf] = bip2num("From -3.6 MiB to +1.24KiB data allowance.")
num = [-3774873.6,1269.76]
spl = ["From ","B to ","B data allowance."]
sgf = [2,3]

>> [num,spl] = bip2num("100 Pixel","Pixel") % Try it without the second option.
num = 100
spl = ["","Pixel"]

>> bip2num(num2bip(pow2(9,40))) % 9 tebi == pow2(9,40) == 9*1024^4 == 9895604649984
ans = 9895604649984

SI Prefixes (Bureau International des Poids et Mesures)

Magnitude | Symbol | Name

1000^-10 | q | quecto

1000^-9 | r | ronto

1000^-8 | y | yocto

1000^-7 | z | zepto

1000^-6 | a | atto

1000^-5 | f | femto

1000^-4 | p | pico

1000^-3 | n | nano

1000^-2 | µ | micro

1000^-1 | m | milli

1000^0 | |

1000^+1 | k | kilo

1000^+2 | M | mega

1000^+3 | G | giga

1000^+4 | T | tera

1000^+5 | P | peta

1000^+6 | E | exa

1000^+7 | Z | zetta

1000^+8 | Y | yotta

1000^+9 | R | ronna

1000^+10 | Q | quetta

Binary Prefixes (IEC 60027-2 A.2 and ISO/IEC 80000-13:2008)

Magnitude | Symbol | Name

1024^1 | Ki | kibi

1024^2 | Mi | mebi

1024^3 | Gi | gibi

1024^4 | Ti | tebi

1024^5 | Pi | pebi

1024^6 | Ei | exbi

1024^7 | Zi | zebi

1024^8 | Yi | yobi

Notes

These functions have been extensively tested against many edge cases, with particular attention to ensuring the correct handling of exponential notation. Compared to similar submissions available on MATLAB File Exchange, these functions correctly:

• parse negative strings (try '-1').
• parse E-notation values (try '1e0', '1e0 k', '1e30').