text2expr -- convert a
character string to an expression
Introductiontext2expr(text) interprets the character
string text as MuPAD input and generates the
corresponding object.
Call(s)text2expr(text)
Parameterstext |
- | a character string |
Returnsa MuPAD object.
Related
Functionscoerce, expr2text, input, int2text, tbl2text, text2int, text2list, text2tbl
Detailstext2expr produces an error. Typically,
strings created from MuPAD objects via expr2text can be reconverted to
corresponding objects.eval.text does not need to be terminated with a
``;'' or a ``:'' character,
respectively.text2expr is a function of the system kernel.
Example
1A character string is converted to a simple expression. The newly created expression is not evaluated automatically:
>> text2expr("21 + 21")
21 + 21
It may be evaluated via eval:
>> eval(%)
42
Example
2A character string is converted to a statement sequence:
>> text2expr("x:= 3; x + 2 + 1"); eval(%)
(x := 3;
x + 2 + 1)
6
>> x
3
>> delete x:
Example
3A matrix is converted to a string:
>> matrix([[a11, a12], [a21, a22]])
+- -+
| a11, a12 |
| |
| a21, a22 |
+- -+
>> expr2text(%)
"Dom::Matrix()(array(1..2, 1..2, (1,1) = a11, (1,2) = a12, (2,\
1) = a21, (2,2) = a22))"
The string is reconverted to a matrix:
>> text2expr(%)
Dom::Matrix()(array(1..2, 1..2, (1, 1) = a11, (1, 2) = a12,
(2, 1) = a21, (2, 2) = a22))
>> eval(%)
+- -+
| a11, a12 |
| |
| a21, a22 |
+- -+