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Converting Between Strings and Symbols

Problem

You want to convert a symbol to a string or vice versa

Solution

The built-in function string->symbol converts from a string to a symbol, and symbol->string does the conversion in the other direction.

For example:

> (string->symbol "hello")
hello
> (symbol->string 'hello)
"hello"

Discussion

Note that since version 299 PLT Scheme is case sensitive, so the symbols 'hello, 'Hello and 'HeLLo' will be different:

> (and (eq? 'hello 'Hello) (eq? 'hello 'HeLLo))
#f

Many other Schemes are case sensitive (though the trend is towards case insensitivity). Using string->symbol is one way of getting around the problem of case-insensitivity when case-sensitive symbols are needed (for example when processing XML):

> (eq? (string->symbol "hello") (string->symbol "Hello"))
#f

Also note that in PLT Scheme there are special quoting rules for symbols that would otherwise be read as something else. For example if you wanted to write a symbol that was bracketed, and so would normally be read as a list, you could write:

> '\(#0000ff\)
|(#0000ff)|
> '|[#0000ff]|
|[#0000ff]|

The symbol doesn't really have the bars or the backslashes in it's name, it's just that it has to be written like that, so the brackets aren't interpreted as lists.