Another means of controlling the flow is to say "If <some circumstance exists>: <do this>." Obviously, if the circumstance does not exist, the computer will ignore the lot. Sometimes, however, it is nice to have a "default setting" for the program's flow, an "else": If <a particular circumstance exists>: <do this> else: <do that>. The following templates and examples illustrate how these two loops are written:
if <condition>: <action to be taken>
if <condition>: <action to be taken> else: <default action>
if c < 0: print c
if animal == dog: print "bow-wow" else: print "meow"
You might think it a bit cludgy to have to write 'if...else' statements for every possible option. You would be right, and this is why Python has an additional, optional part of the 'if' loop: 'elif'. 'elif' is for the various options that fit neither the 'if' nor the else. The template and an example are as follows:
if <1st condition>: <action to be taken> elif <2nd condition>: <other action to be taken> else: <default action>
if animal == 'dog': print "bow-wow" elif animal == 'cat': print "meow" else: print "cockadoodledoo!"