The structure of the if-else statement has the form:
if (condition1 is true):
do A
elif (condition2 is true):
do B
else:
do C
example 1: grading test scores
In [1]: grade=None
In [2]: score=86
In [3]: if (score>93):
...: grade='A'
...: elif (score>85):
...: grade='B'
...: else:
grade='C'
In [4]: grade
Out[4]: 'B'
example 2: palindrome
In [8]: seq1="ACTCA"
In [9]: if seq1==seq1[::-1]:
...: print("%s is a palindrome!" % seq1)
...:
ACTCA is a palindrome!
