Python使用list和tuple+条件判断详解-创新互联

list

list是一种有序的集合，可以随时添加和删除其中的元素。跟java不一样的是 可以使用arr[-1] 0>-x >=- len(arr) 索引的数字为 0~ len(arr)-1 -len(arr)~ -1 超过会报错

classmates= ['A','B','C','D','E']
print(classmates)
print(len(classmates))
for i in classmates:
  print(i)

'''
['A', 'B', 'C', 'D', 'E']
5
A
B
C
D
E
'''
for i in range(0,len(classmates)):
  print(classmates[i])
'''
A
B
C
D
E
'''
classmates= ['A','B','C','D','E']
print(classmates[-1])
print(classmates[-2])
print(classmates[-3])
print(classmates[-4])
print(classmates[-5])
'''
print(classmates[-6])
IndexError: list index out of range
'''
'''
E
D
C
B
A
'''