Python 检查数组元素是否存在类似PHP isset()方法

Look before you leap (LBYL):

if idx < len(array):
array[idx]
else:
#handle this

Easier to ask forgiveness than permission (EAFP):


try:
array[idx]
except IndexError:
#handle this

if 'test' in ['demo','example']:

...

else:

...