print(float('inf')/float('inf'))
print(float('inf')*float('-inf'))
print(float('inf')+float('inf'))
print(float('inf')-float('inf'))
print(float('inf')-float('-inf'))
print(-float('inf')-float('inf'))
输出:
nan -inf inf nan inf -inf

print(float('inf')/float('inf'))
print(float('inf')*float('-inf'))
print(float('inf')+float('inf'))
print(float('inf')-float('inf'))
print(float('inf')-float('-inf'))
print(-float('inf')-float('inf'))
输出:
nan -inf inf nan inf -inf