判断一字符串是否对称，如：abccba

# 1.判断一字符串是不是对称的，如：abccba
def is_symmetrical(str):
length = len(str)
for index in range(length / 2):
if str[index] == str[length - index - 1]:
pass
else:
return False
return True
 if __name__ == "__main__":
 print is_symmertrical("abcdcba"),
 print is_symmertrical("abccaa"),
运行结果: True False
# 2.用递归的方法判断整数组a[N]是不是升序排列
# index初始化为1
def is_asc(sequence, index):
if index > len(sequence) - 1:
return True
if sequence[index] > sequence[index - 1]:
return is_asc(sequence, index + 1)
return False
if __name__ == "__main__":
 sequence1 = [1, 100, 100, 200]
 print is_asc(sequence1, 1),
 sequence2 = [1, 100, 101, 500]
 print is_asc(sequence2, 1),
运行结果: False True