假定表table1中phone列有空值,则selectcount(*)fromtable1与selectcount(phone)fromtable1相等吗?() A: 相等 B: 不相等
假定表table1中phone列有空值,则selectcount(*)fromtable1与selectcount(phone)fromtable1相等吗?() A: 相等 B: 不相等
关干HiveSQL运行原理,描述不正确的选项有? A: 所有HQL都会转化为MapReduce任务执行 B: DDL语句不提交任务到MapReduce,而是直接操作元数据 C: 对于selectcount(*)fromtable操作,一定会启reduce任务 D: 对于select*fromtable语句不会启MapReduce
关干HiveSQL运行原理,描述不正确的选项有? A: 所有HQL都会转化为MapReduce任务执行 B: DDL语句不提交任务到MapReduce,而是直接操作元数据 C: 对于selectcount(*)fromtable操作,一定会启reduce任务 D: 对于select*fromtable语句不会启MapReduce
关干HiveSQL运行原理,描述不正确的选项有 A: 所有HQL都会转化为MapReduce B: 任务执行DDL语句不提交任务到MapReduce,而是直接操作元数据 C: 对于selectcount(*)fromtable操作,一定会启动reduce任务 D: 对于select*fromtable语句不会启MapReduce
关干HiveSQL运行原理,描述不正确的选项有 A: 所有HQL都会转化为MapReduce B: 任务执行DDL语句不提交任务到MapReduce,而是直接操作元数据 C: 对于selectcount(*)fromtable操作,一定会启动reduce任务 D: 对于select*fromtable语句不会启MapReduce
for i in range(b.max_row): for j in range(b.max_column): print(b.cell(row=i,column=j).value)上面语句运行的结果是:__________。 A: 1 1 1 1 1 1 1 1 1 1 B: 1111111111 C: 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 D: 出现异常
for i in range(b.max_row): for j in range(b.max_column): print(b.cell(row=i,column=j).value)上面语句运行的结果是:__________。 A: 1 1 1 1 1 1 1 1 1 1 B: 1111111111 C: 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 D: 出现异常
【单选题】CDMA通信的基站,假定基站A的码片序列是+1 +1 +1 -1 -1 +1 -1 -1,基站发射bit为101时,实际发射的信号是 A. +1 +1 +1 -1 -1 +1 -1 -1 +1 +1 +1 -1 -1 +1 -1 -1 –1 –1 –1 +1 +1 –1 +1 +1 B. +1 +1 +1 -1 -1 +1 -1 -1 –1 –1 –1 +1 +1 –1 +1 +1 +1 +1 +1 -1 -1 +1 -1 -1 C. +1 +1 +1 -1 -1 +1 -1 -1 +1 +1 +1 -1 -1 +1 -1 -1 +1 +1 +1 -1 -1 +1 -1 -1 D. –1 –1 –1 +1 +1 –1 +1 +1 –1 –1 –1 +1 +1 –1 +1 +1 –1 –1 –1 +1 +1 –1 +1 +1
【单选题】CDMA通信的基站,假定基站A的码片序列是+1 +1 +1 -1 -1 +1 -1 -1,基站发射bit为101时,实际发射的信号是 A. +1 +1 +1 -1 -1 +1 -1 -1 +1 +1 +1 -1 -1 +1 -1 -1 –1 –1 –1 +1 +1 –1 +1 +1 B. +1 +1 +1 -1 -1 +1 -1 -1 –1 –1 –1 +1 +1 –1 +1 +1 +1 +1 +1 -1 -1 +1 -1 -1 C. +1 +1 +1 -1 -1 +1 -1 -1 +1 +1 +1 -1 -1 +1 -1 -1 +1 +1 +1 -1 -1 +1 -1 -1 D. –1 –1 –1 +1 +1 –1 +1 +1 –1 –1 –1 +1 +1 –1 +1 +1 –1 –1 –1 +1 +1 –1 +1 +1
for i in range(1,11): for j in range(1,11): b.cell(row=i,column=j).value=1 #b是一个工作表对象for i in range(1,11): for j in range(1,11): print(b.cell(row=i,column=j).value,end=" ") print()上面程序代码运行的结果是()。 A: 1 B: 1 1 1 1 1 1 1 1 1 1 C: 1111111111 D: 1 1 1 1 1 1 1 1 1 11 1 1 1 1 1 1 1 1 11 1 1 1 1 1 1 1 1 11 1 1 1 1 1 1 1 1 11 1 1 1 1 1 1 1 1 11 1 1 1 1 1 1 1 1 11 1 1 1 1 1 1 1 1 11 1 1 1 1 1 1 1 1 11 1 1 1 1 1 1 1 1 11 1 1 1 1 1 1 1 1 1
for i in range(1,11): for j in range(1,11): b.cell(row=i,column=j).value=1 #b是一个工作表对象for i in range(1,11): for j in range(1,11): print(b.cell(row=i,column=j).value,end=" ") print()上面程序代码运行的结果是()。 A: 1 B: 1 1 1 1 1 1 1 1 1 1 C: 1111111111 D: 1 1 1 1 1 1 1 1 1 11 1 1 1 1 1 1 1 1 11 1 1 1 1 1 1 1 1 11 1 1 1 1 1 1 1 1 11 1 1 1 1 1 1 1 1 11 1 1 1 1 1 1 1 1 11 1 1 1 1 1 1 1 1 11 1 1 1 1 1 1 1 1 11 1 1 1 1 1 1 1 1 11 1 1 1 1 1 1 1 1 1
下列哪个码片序列不能用于CDMA通信 A: ( -1 -1 -1 +1 +1 -1 +1 +1 ) B: ( -1 -1 +1 -1 +1 +1 +1 -1 ) C: ( -1 +1 -1 +1 +1 -1 -1 -1 ) D: ( -1 +1 -1 -1 -1 -1 +1 -1 )
下列哪个码片序列不能用于CDMA通信 A: ( -1 -1 -1 +1 +1 -1 +1 +1 ) B: ( -1 -1 +1 -1 +1 +1 +1 -1 ) C: ( -1 +1 -1 +1 +1 -1 -1 -1 ) D: ( -1 +1 -1 -1 -1 -1 +1 -1 )
请仔细观察下面行列式的计算过程,如果四个等号都理解了,请选择A,否则请选择B。 | a 1 1 1 1 | |a+4 a+4 a+4 a+4 a+4| | 1 a 1 1 1 | | 1 a 1 1 1 | | 1 1 a 1 1 |= | 1 1 a 1 1 | | 1 1 1 a 1 | | 1 1 1 a 1 | | 1 1 1 1 a | | 1 1 1 1 a | | 1 1 1 1 1 | | 1 a 1 1 1 | =(a+4) | 1 1 a 1 1 | | 1 1 1 a 1 | | 1 1 1 1 a | | 1 1 1 1 1 | | 0 a–1 0 0 0 | =(a+4) | 0 0 a–1 0 0 | | 0 0 0 a–1 0 | | 0 0 0 0 a–1 | =(a+4)(a–1)^4
请仔细观察下面行列式的计算过程,如果四个等号都理解了,请选择A,否则请选择B。 | a 1 1 1 1 | |a+4 a+4 a+4 a+4 a+4| | 1 a 1 1 1 | | 1 a 1 1 1 | | 1 1 a 1 1 |= | 1 1 a 1 1 | | 1 1 1 a 1 | | 1 1 1 a 1 | | 1 1 1 1 a | | 1 1 1 1 a | | 1 1 1 1 1 | | 1 a 1 1 1 | =(a+4) | 1 1 a 1 1 | | 1 1 1 a 1 | | 1 1 1 1 a | | 1 1 1 1 1 | | 0 a–1 0 0 0 | =(a+4) | 0 0 a–1 0 0 | | 0 0 0 a–1 0 | | 0 0 0 0 a–1 | =(a+4)(a–1)^4
共有4个站进行码分多址通信。4个站的码片序列为:a:(-1 -1 -1 +1 +1 -1 +1 +1) b:(-1 -1 +1 -1 +1 +1 +1 -1) c:(-1 +1 -1 +1 +1 +1 -1 -1) d:(-1 +1 -1 -1 -1 -1 +1 -1) 现收到这样的码片序列:(-1 +1 -3 +1 -1 -3 +1 +1),则( )发送1。
共有4个站进行码分多址通信。4个站的码片序列为:a:(-1 -1 -1 +1 +1 -1 +1 +1) b:(-1 -1 +1 -1 +1 +1 +1 -1) c:(-1 +1 -1 +1 +1 +1 -1 -1) d:(-1 +1 -1 -1 -1 -1 +1 -1) 现收到这样的码片序列:(-1 +1 -3 +1 -1 -3 +1 +1),则( )发送1。
共有四个站进行CDMA通信,现收到这样的码片序列(-3 +1 -1 -1 +1 +1 +1 -3),则下列站点发送了数据1的是( ) A: (-1 -1 -1 +1 +1 -1 +1 +1) B: (-1 -1 +1 -1 +1 +1 +1 -1) C: (-1 +1 -1 +1 +1 +1 -1 -1) D: (-1 +1 -1 -1 -1 -1 +1 -1)
共有四个站进行CDMA通信,现收到这样的码片序列(-3 +1 -1 -1 +1 +1 +1 -3),则下列站点发送了数据1的是( ) A: (-1 -1 -1 +1 +1 -1 +1 +1) B: (-1 -1 +1 -1 +1 +1 +1 -1) C: (-1 +1 -1 +1 +1 +1 -1 -1) D: (-1 +1 -1 -1 -1 -1 +1 -1)