str2number - Fast replacement for str2num and str2double

Fast replacement for str2num and str2double; converts simple scalar input string(s) to number(s)

str2number - Fast replacement for str2num and str2double; convert input string(s) to number(s)

result = str2number(str) % a single char/string input value

results = str2number(cellStrs) % cell-array of input char/string values

str2number converts char/string input value(s) to their numeric value(s).

This function can be much faster than str2num/str2double/sscanf for the common cases of simple numeric values. However, str2number cannot handle complex/imaginary values, exponents, and non-scalar values (as opposed to cell-arrays of scalar values, that are accepted). If you expect such non-supported values as inputs, then use str2num/str2double instead.

The input str argument can be a char array ('12.3'), or a string ("12.3"), or a cell array of chars/strings. The period ('.') is the expected decimal point.

The conversion result is a numeric value in case the input(s) can be converted into a numeric value. If an input cannot be converted into a number, then the original string is returned, like the builtin str2num function, and unlike the builtin str2double function (which returns NaN for unconvertable input values).

IMPORTANT: str2number was optimized for best performance, and often works faster than str2num/str2double/sscanf, but it only works for scalar non-complex, non-exponent values! See limitations below for details.

Limitations and differences compared to str2num/str2double:

- Inputs with a decimal sign different than a period ('.') are not converted

- Inputs with a thousands seperators (, or ' or .) are not converted

- Exponents (e.g. '1.2e3') are not converted

- Complex/imaginary values (e.g. '1+2i') are not converted

- Non-scalar values (e.g. '1,2' or '12 13') are not converted (but a cell-array of scalar values is acceptable)

- The original input string is returned if it cannot be converted into a number, unlike str2double (which returns NaN)

- Cell-arrays of chars and strings are accepted, unlike str2num

- String arrays are not accepted ; use str2double or convert to cell array

Usage examples:

str2number('12.34') % => [12.34] % scalar input value (char array)

str2number("12.34") % => [12.34] % scalar input value (string)

str2number('12,34') % => '12,34' % comma is not supported

str2number("1'234") % => "12'34" % thousands seperator is not supported

str2number('1.2e3') % => '1.2e3' % exponents are not supported

str2number('12+3i') % => '12+3i' % complex values are not supported

str2number('12 34') % => '12 34' % non-scalars are not supported

str2number({'12','34'}) % => {12,34} % cell-array of input values

str2number({'12','34','ab'}) % => {12,34,'ab'} % cell-array of input values

Bugs and suggestions:

Please send to Yair Altman (altmany at gmail dot com)

See also:

str2num, str2double, sscanf