On Tue, Apr 3, 2012 at 10:50 AM, Peter Otten <__pete...@web.de> wrote: > Alan Gauld wrote: >> On 03/04/12 15:54, Khalid Al-Ghamdi wrote: >> >>> dom="".join(choice(lc) for j in range (dlen)) >>> >>> how does the interpreter know what "j" is supposed to refer to when it >>> was not mentioned prior?
+1 everyone else's replies so far. i'll add the following: you create variables by assigning things to them. in this example, no prior code used the variable 'x': >>> x = 10 >>> print x 10 similarly, when used in a for-loop, it's like you had an "invisible" assignment at the "top" of the loop. here's an example: >>> for i in range(5): ... print i ... 0 1 2 3 4 >>> print i 4 notice that the 'i' variable is still there even after the loop has ended. it's as if you did the following: >>> i = 0 >>> print i 0 >>> i = 1 : >>> i = 4 >>> print i # 1st time, part of the "loop" 4 >>> print i # 2nd time, "outside" of the loop 4 hope this helps! --wesley - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - "A computer never does what you want... only what you tell it." wesley chun : wescpy at gmail : @wescpy/+wescpy Python training & consulting : CyberwebConsulting.com "Core Python" books : CorePython.com Python blog: wescpy.blogspot.com _______________________________________________ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor