help mata strtoreal()
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Title
[M-5] strtoreal() -- Convert string to real
Syntax
real matrix strtoreal(string matrix S)
real scalar _strtoreal(string matrix S, R)
Description
strtoreal(S) returns S converted to real. Elements of S that cannot be
converted are returned as . (missing value).
_strtoreal(S, R) does the same as above -- it returns the converted
values in R -- and it returns the number of elements that could not be
converted. In such cases, the corresponding value of R contains .
(missing).
Remarks
strtoreal("1.5") returns (numeric) 1.5.
strtoreal("-2.5e+1") returns (numeric) -25.
strtoreal("not a number") returns (numeric) . (missing).
Typically, strtoreal(S) and _strtoreal(S, R) are used with scalars, but
if applied to a vector or matrix S, element-by-element results are
returned.
In performing the conversion, leading and trailing blanks are ignored:
"1.5" and " 1.5 " both convert to (numeric) 1.5, but "1.5 kilometers"
converts to . (missing). Use strtoreal(tokens(S)[1]) to convert just the
first space-delimited part.
All Stata numeric formats are understood, such as 0, 1, -2, 1.5, 1.5e+2,
and -1.0x+8, as well as the missing-value codes ., .a, .b, ..., .z.
Thus using strtoreal(S), if an element of S converts to . (missing), you
cannot tell whether the element was valid and equal to "." or the element
was invalid and so defaulted to . (missing), such as if S contained "cat"
or "dog" or "1.5 kilometers".
When it is important to distinguish between these cases, use
_strtoreal(S, R). The conversion is returned in R and the function
returns the number of elements that were invalid. If _strtoreal()
returns 0, then all values were valid.
Conformability
strtoreal(S):
input:
S: r x c
output:
result: r x c
_strtoreal(S, R):
input:
S: r x c
output:
R: r x c
result: 1 x 1
Diagnostics
strtoreal(S) returns a missing value wherever an element of S cannot be
converted to a number.
_strtoreal(S, R) does the same, but the result is returned in R.
Source code
strtoreal.mata; _strtoreal() is built in.
Also see
Manual: [M-5] strtoreal()
Help: [M-5] strofreal(); [M-4] string
