prepare command and use startswith option with string-CodePudding

I am receiving some rule from file and would like to prepare query at run time but getting following error. any input.

a = "AC"
cond = "startswith"
rule = "AC"
eval("%s.%s(%s)" %(a, cond, rule))

CodePudding user response：

If you must use eval, use %r in your format string when you want to substitute in strings, to get the repr of the str (including quotes) so they remain valid string literals, not raw names; as written, you're trying to run the code AC.startswith(AC), with %r for first and third placeholder (eval("%r.%s(%r)" %(a, cond, rule))) you'd be running "AC".startswith("AC").

CodePudding user response：

Try in this way:

eval(("'%s'.%s('%s')" %(a, cond, rule)))

You forgot single quotes to define strings in function evaluation