[Python-Dev] PEP_215_ (string interpolation) alternative EvalDict

2002年1月14日 21:10:55 -0500

Neil Schemenauer wrote:
>> Jason Orendorff wrote:
> > The substitution only happens once.
>> My example was not well thought out. I was thinking something more
> like:
>> secret_key = "spam"
> user = "joe"
> x = "$user said: " + raw_input()
> print $x
>> That wouldn't work either since $ only evaluates literals. Amazing what
> you learn by actually reading the PEP. Yes, I'm an idiot.

Sorry, I haven't followed this thread real closely, but I thought
someone said eval() was used under the covers.
If x is eval'ed and the string is as above, I get the following in 2.1:
	>>> secret_key = 'spam'
	>>> x = raw_input('? ')
	? eval("secret_key")
	# Is the following commented print equivalent the the line below it?
	### print "You entered $x"
	>>> print "You entered", eval(x)
	You entered spam
	>>> print "You entered %(x)s" % locals()
	You entered eval("secret_key")
Not sure if that's the same as what you are talking about though.
Neal