It seems both of the below codes are printing the same, then what is the need of "else" block after "for" loop in python.
Code 1:
for i in range(10):
print i
else:
print "after for loop"
Code 2:
for i in range(10):
print i
print "after for loop"
Thanks in advance.
Loop statements may have an
elseclause; it is executed when the loop terminates through exhaustion of the list (withfor) or when the condition becomes false (withwhile), but not when the loop is terminated by abreakstatement.
Follow the link for an example how this can be used.
else executes after for providing for wasn't terminated with break:
for i in range(10):
print i
if i == 8:
break # termination, no else
else:
print "after for loop"
break cannot be reached. So the loop acts as if there was no break, going to else.
This was originally enacted in order to get rid of all the "GOTO" statements in procedures without using flags: It means "NO BREAK"
for i, value in enumerate(sequence):
if value == target:
break
else: #<-- if we finish the loop and did not encounter break, return -1
return -1
return 1 #<-- if we did encounter break, return 1
You can watch Raymond Hettinger's Pycon talk that mentions the for/else construct here: Transforming Code into Beautiful, Idiomatic Python
