Python: for loops and xrange() -

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• scope of python variable in loop 7 answers

i learning python , came across 'for loop' let's have program asks 5 numbers. know it's pointless it's example. anyway, if did this, wouldn't restart cycle.

mynumbers = [] x in xrange(5):     try:         mynumbers.append( int(raw_input()) )     except valueerror:         mynumbers = []         x = -1 

i thought if had reset x -1 make loop go on more, never restarted. still only went 5 times. reason why put -1 there because x count 0 right after that. tried find solutions, there weren't any. thank if try me.

xrange() (or range() ) called generator functions, x local variable loop assigns next value in loop to.

xrange() returns values in range given in parameters 1 1 , , loop assigns variable x. if change value of x within loop, xrange() has no idea such change , still provide next value in range.

example of generator functions -

def myrange(a):     = 0     while < a:         yield         = + 1  >>> x in  myrange(10): ...     print(x) ...     x = 1 ... 0 1 2 3 4 5 6 7 8 9 

the value change in x never propagated range() or xrange() function.