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parse(T::Type, str, base=Int)

parse(type, str, [base])

Parse a string as a number. If the type is an integer type, then a base can be specified (the default is 10). If the type is a floating point type, the string is parsed as a decimal floating point number. If the string does not contain a valid number, an error is raised.

Examples

1. Parse a simple mathematical expression:

   julia> parse("2 + 3")
   :(2 + 3)

   This example parses the expression "2 + 3" and returns an expression object that represents the addition operation.

2. Parse a more complex expression with variables:

   julia> parse("x^2 + 2 * y - z")
   :((x ^ 2) + (2 * y) - z)

   It parses the expression "x^2 + 2 * y - z" and returns an expression object with variables x, y, and z.

3. Handle syntax errors:

   julia> parse("3 + ")
   ERROR: syntax: expected expression

   In this example, the expression "3 + " is invalid, and parse raises a syntax error.

4. Disable error raising upon evaluation:

   julia> parse("5 / 0", raise=false)
   :((5 / 0))

   By passing raise=false as an argument, parse will return an expression even if it contains an error. In this case, division by zero.

Common mistake example:

julia> parse("x + y")
:((x + y))

In this example, the variables x and y are not defined, so evaluating the parsed expression will raise an error. Make sure to define any variables used in the parsed expression beforehand.

See Also

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