我正在搞乱多维数组和指针.我一直在看一个程序,它打印出一个简单数组的内容和地址.这是我的数组声明:
int zippo[4][2] = { {2,4},
{6,8},
{1,3},
{5,7} };
我目前的理解是它zippo是一个指针,它可以保存其他几个指针的地址.默认情况下,zippo持有指针的地址zippo[0],也可以容纳指针的地址zippo[1],zippo[2]和zippo[3].
现在,请采取以下声明:
printf("zippo[0] = %p\n", zippo[0]);
printf(" *zippo = %p\n", *zippo);
printf(" zippo = %p\n", zippo);
在我的机器上,它提供以下输出:
zippo[0] = 0x7fff170e2230
*zippo = 0x7fff170e2230
zippo = 0x7fff170e2230
我完全理解为什么zippo[0]并*zippo拥有相同的价值.它们都是指针,它们都存储整数2的地址(默认),或者zippo[0][0].但是,zippo共享相同的内存地址又是什么呢？不zippo应该存储指针的地址zippo[0]？Whaaaat？
是否可以用于usort对多维数组中的多个字段进行排序？例如,我想name按字母顺序排序,然后从那些我想要排序的记录中排序age.这可能用sort吗？
Array (
[0] => Array (
[name] => Jonah
[age] => 27
)
[1] => Array (
[name] => Bianca
[age] => 32
)
)
我正在尝试推送到二维数组而不会弄乱,目前我的数组是:
var myArray = [
[1,1,1,1,1],
[1,1,1,1,1],
[1,1,1,1,1]
]
我正在尝试的代码是:
var r = 3; //start from rows 3
var c = 5; //start from col 5
var rows = 8;
var cols = 7;
for (var i = r; i < rows; i++)
{
for (var j = c; j < cols; j++)
{
myArray[i][j].push(0);
}
}
这应该导致以下结果:
var myArray = [
[1,1,1,1,1,0,0],
[1,1,1,1,1,0,0],
[1,1,1,1,1,0,0],
[0,0,0,0,0,0,0],
[0,0,0,0,0,0,0],
[0,0,0,0,0,0,0],
]
但它不会也不确定这是否是正确的方法.
所以问题是如何实现这一目标？
在URL查询字符串中使用多维数组合成器实际上是安全/有效的吗？
http://example.com?abc[]=123&abc[]=456
它似乎适用于每个浏览器,我一直认为它可以使用,但在本文中评论它不是:http://www.456bereastreet.com/archive/201008/what_characters_are_allowed_unencoded_in_query_strings/#comment4
我想听听第二个意见.
我有一个如下命名的数组$test_package_data.作为参考我打印它的前两个元素:
Array
(
[0] => Array
(
[test_pack_id] => 9f27643023a83addd5eed41c4aade840
[test_pack_name] => Exams Combo
[test_pack_desc] => This Package contains 24 tests of Reasoning, English and Quantitative Aptitude.
Total Tests in this Package : 26
[test_pack_type_id] => 3
[test_pack_image] =>
[test_pack_validity_year] => 0
[test_pack_validity_month] => 3
[test_pack_validity_days] => 0
[test_pack_plan] => paid
[test_pack_price] => 399.00
[test_pack_no_tests] => 0
[test_pack_publish] => yes
[test_pack_sold] => 1
[test_pack_created_staff_id] => ff8d4a5ea6bf11dce105aa2fa7b959b8
[test_pack_updated_staff_id] => 81c4e3607c7e56bbf5461ef150437675
[test_pack_created_date] => 303
[test_pack_updated_date] => 1349235701
[test_pack_purchase_date] => 255 …我想在选定的轴上用0填充一个numpy张量.例如,我有r形状的张量,(4,3,2)但我只对填充最后两个轴(即仅填充矩阵)感兴趣.是否可以使用单行python代码？
如何找到具有非相等索引的多维数组的长度？
例如,我有 int[][] pathList = new int[6][4]
如果没有对索引进行硬编码,我需要找到'6'和'4'.
我可以找到6 pathList.length,但如何获得'4'？
我有一个int16_t的2D查找表.
int16_t my_array[37][73] = {{**DATA HERE**}}
我有一个值的混合,范围从int8_t的范围之上到刚好低于int8_t的范围,并且一些值重复自己.我试图减少这个查找表的大小.
到目前为止我所做的是将每个int16_t值拆分为两个int8_t值,以显示浪费的字节.
int8_t part_1 = original_value >> 4;
int8_t part_2 = original_value & 0x0000FFFF;
// If the upper 4 bits of the original_value were empty
if(part_1 == 0) wasted_bytes_count++;
我可以轻松删除浪费一个字节空间的零值int8_t,我也可以删除重复值,但我的问题是如何在保留基于两个索引查找的能力的同时删除这些值？
我打算将其转换为一维数组,并在每个重复值后添加一个数字,表示已删除的重复数量,但我正在努力解决我将如何识别什么是查找值以及什么是重复计数.此外,通过剥离浪费的字节的零int8_t值进一步复杂化.
编辑:此数组已存储在ROM中.RAM比ROM更受限制,因此它已经存储在ROM中.
编辑:我会尽快发布这个问题的赏金.我需要一个完整的答案,如何存储信息并检索它.只要我可以获得相同的值,它就不需要是2D数组.
编辑:添加下面的实际数组:
{150,145,140,135,130,125,120,115,110,105,100,95,90,85,80,75,70,65,60,55,50,45,40,35,30,25,20,15,10,5,0,-4,-9,-14,-19,-24,-29,-34,-39,-44,-49,-54,-59,-64,-69,-74,-79,-84,-89,-94,-99,104,109,114,119,124,129,134,139,144,149,154,159,164,169,174,179,175,170,165,160,155,150}, \
{143,137,131,126,120,115,110,105,100,95,90,85,80,75,71,66,62,57,53,48,44,39,35,31,27,22,18,14,9,5,1,-3,-7,-11,-16,-20,-25,-29,-34,-38,-43,-47,-52,-57,-61,-66,-71,-76,-81,-86,-91,-96,101,107,112,117,123,128,134,140,146,151,157,163,169,175,178,172,166,160,154,148,143}, \
{130,124,118,112,107,101,96,92,87,82,78,74,70,65,61,57,54,50,46,42,38,34,31,27,23,19,16,12,8,4,1,-2,-6,-10,-14,-18,-22,-26,-30,-34,-38,-43,-47,-51,-56,-61,-65,-70,-75,-79,-84,-89,-94,100,105,111,116,122,128,135,141,148,155,162,170,177,174,166,159,151,144,137,130}, \
{111,104,99,94,89,85,81,77,73,70,66,63,60,56,53,50,46,43,40,36,33,30,26,23,20,16,13,10,6,3,0,-3,-6,-9,-13,-16,-20,-24,-28,-32,-36,-40,-44,-48,-52,-57,-61,-65,-70,-74,-79,-84,-88,-93,-98,103,109,115,121,128,135,143,152,162,172,176,165,154,144,134,125,118,111}, \
{85,81,77,74,71,68,65,63,60,58,56,53,51,49,46,43,41,38,35,32,29,26,23,19,16,13,10,7,4,1,-1,-3,-6,-9,-13,-16,-19,-23,-26,-30,-34,-38,-42,-46,-50,-54,-58,-62,-66,-70,-74,-78,-83,-87,-91,-95,100,105,110,117,124,133,144,159,178,160,141,125,112,103,96,90,85}, \
{62,60,58,57,55,54,52,51,50,48,47,46,44,42,41,39,36,34,31,28,25,22,19,16,13,10,7,4,2,0,-3,-5,-8,-10,-13,-16,-19,-22,-26,-29,-33,-37,-41,-45,-49,-53,-56,-60,-64,-67,-70,-74,-77,-80,-83,-86,-89,-91,-94,-97,101,105,111,130,109,84,77,74,71,68,66,64,62}, \
{46,46,45,44,44,43,42,42,41,41,40,39,38,37,36,35,33,31,28,26,23,20,16,13,10,7,4,1,-1,-3,-5,-7,-9,-12,-14,-16,-19,-22,-26,-29,-33,-36,-40,-44,-48,-51,-55,-58,-61,-64,-66,-68,-71,-72,-74,-74,-75,-74,-72,-68,-61,-48,-25,2,22,33,40,43,45,46,47,46,46}, \
{36,36,36,36,36,35,35,35,35,34,34,34,34,33,32,31,30,28,26,23,20,17,14,10,6,3,0,-2,-4,-7,-9,-10,-12,-14,-15,-17,-20,-23,-26,-29,-32,-36,-40,-43,-47,-50,-53,-56,-58,-60,-62,-63,-64,-64,-63,-62,-59,-55,-49,-41,-30,-17,-4,6,15,22,27,31,33,34,35,36,36}, \
{30,30,30,30,30,30,30,29,29,29,29,29,29,29,29,28,27,26,24,21,18,15,11,7,3,0,-3,-6,-9,-11,-12,-14,-15,-16,-17,-19,-21,-23,-26,-29,-32,-35,-39,-42,-45,-48,-51,-53,-55,-56,-57,-57,-56,-55,-53,-49,-44,-38,-31,-23,-14,-6,0,7,13,17,21,24,26,27,29,29,30}, \
{25,25,26,26,26,25,25,25,25,25,25,25,25,26,25,25,24,23,21,19,16,12,8,4,0,-3,-7,-10,-13,-15,-16,-17,-18,-19,-20,-21,-22,-23,-25,-28,-31,-34,-37,-40,-43,-46,-48,-49,-50,-51,-51,-50,-48,-45,-42,-37,-32,-26,-19,-13,-7,-1,3,7,11,14,17,19,21,23,24,25,25}, \
{21,22,22,22,22,22,22,22,22,22,22,22,22,22,22,22,21,20,18,16,13,9,5,1,-3,-7,-11,-14,-17,-18,-20,-21,-21,-22,-22,-22,-23,-23,-25,-27,-29,-32,-35,-37,-40,-42,-44,-45,-45,-45,-44,-42,-40,-36,-32,-27,-22,-17,-12,-7,-3,0,3,7,9,12,14,16,18,19,20,21,21}, \
{18,19,19,19,19,19,19,19,19,19,19,19,19,19,19,19,18,17,16,14,10,7,2,-1,-6,-10,-14,-17,-19,-21,-22,-23,-24,-24,-24,-24,-23,-23,-23,-24,-26,-28,-30,-33,-35,-37,-38,-39,-39,-38,-36,-34,-31,-28,-24,-19,-15,-10,-6,-3,0,1,4,6,8,10,12,14,15,16,17,18,18}, \
{16,16,17,17,17,17,17,17,17,17,17,16,16,16,16,16,16,15,13,11,8,4,0,-4,-9,-13,-16,-19,-21,-23,-24,-25,-25,-25,-25,-24,-23,-21,-20,-20,-21,-22,-24,-26,-28,-30,-31,-32,-31,-30,-29,-27,-24,-21,-17,-13,-9,-6,-3,-1,0,2,4,5,7,9,10,12,13,14,15,16,16}, \
{14,14,14,15,15,15,15,15,15,15,14,14,14,14,14,14,13,12,11,9,5,2,-2,-6,-11,-15,-18,-21,-23,-24,-25,-25,-25,-25,-24,-22,-21,-18,-16,-15,-15,-15,-17,-19,-21,-22,-24,-24,-24,-23,-22,-20,-18,-15,-12,-9,-5,-3,-1,0,1,2,4,5,6,8,9,10,11,12,13,14,14}, \
{12,13,13,13,13,13,13,13,13,13,13,13,12,12,12,12,11,10,9,6,3,0,-4,-8,-12,-16,-19,-21,-23,-24,-24,-24,-24,-23,-22,-20,-17,-15,-12,-10,-9,-9,-10,-12,-13,-15,-17,-17,-18,-17,-16,-15,-13,-11,-8,-5,-3,-1,0,1,1,2,3,4,6,7,8,9,10,11,12,12,12}, \
{11,11,11,11,11,12,12,12,12,12,11,11,11,11,11,10,10,9,7,5,2,-1,-5,-9,-13,-17,-20,-22,-23,-23,-23,-23,-22,-20,-18,-16,-14,-11,-9,-6,-5,-4,-5,-6,-8,-9,-11,-12,-12,-12,-12,-11,-9,-8,-6,-3,-1,0,0,1,1,2,3,4,5,6,7,8,9,10,11,11,11}, \
{10,10,10,10,10,10,10,10,10,10,10,10,10,10,9,9,9,7,6,3,0,-3,-6,-10,-14,-17,-20,-21,-22,-22,-22,-21,-19,-17,-15,-13,-10,-8,-6,-4,-2,-2,-2,-2,-4,-5,-7,-8,-8,-9,-8,-8,-7,-5,-4,-2,0,0,1,1,1,2,2,3,4,5,6,7,8,9,10,10,10}, \
{9,9,9,9,9,9,9,10,10,9,9,9,9,9,9,8,8,6,5,2,0,-4,-7,-11,-15,-17,-19,-21,-21,-21,-20,-18,-16,-14,-12,-10,-8,-6,-4,-2,-1,0,0,0,-1,-2,-4,-5,-5,-6,-6,-5,-5,-4,-3,-1,0,0,1,1,1,1,2,3,3,5,6,7,8,8,9,9,9}, \
{9,9,9,9,9,9,9,9,9,9,9,9,8,8,8,8,7,5,4,1,-1,-5,-8,-12,-15,-17,-19,-20,-20,-19,-18,-16,-14,-11,-9,-7,-5,-4,-2,-1,0,0,1,1,0,0,-2,-3,-3,-4,-4,-4,-3,-3,-2,-1,0,0,0,0,0,1,1,2,3,4,5,6,7,8,8,9,9}, \
{9,9,9,8,8,8,9,9,9,9,9,8,8,8,8,7,6,5,3,0,-2,-5,-9,-12,-15,-17,-18,-19,-19,-18,-16,-14,-12,-9,-7,-5,-4,-2,-1,0,0,1,1,1,1,0,0,-1,-2,-2,-3,-3,-2,-2,-1,-1,0,0,0,0,0,0,0,1,2,3,4,5,6,7,8,8,9}, \ …我已经做了很多关于溢出和谷歌的调查,但没有一个结果适用于我的具体情况.
我有一个名为$ holder的占位符数组,值如下:
Array (
[0] => Array (
[id] => 1
[pid] => 121
[uuid] => 1
)
[1] => Array (
[id] => 2
[pid] => 13
[uuid] => 1
)
[2] => Array (
[id] => 5
[pid] => 121
[uuid] => 1
)
)
我试图从这个多维数组中提取不同的/唯一的值.我想要的最终结果是包含(13,121)或(最好)数组的变量,如下所示:Array([0] => 13 [1] => 121)
我再次尝试过序列化等等,但是在每个数组中使用单个键操作时,我不太明白它是如何工作的.
我试着尽可能清楚.我希望它有意义......
我不想使用锯齿状数组,我有一个2D数组,我想得到一个完整的列或行而不通过它循环.有没有人知道如何做到这一点.
double [,] array = new double [3,3] ;
1 2 3
4 5 6
Out: 1 2 3 or 2 5