大约有 48,000 项符合查询结果（耗时：0.0136秒） [XML]
How do I spool to a CSV formatted file using SQLPLUS?
...you want for numbers (avoid scientific notation on IDs)
spool myfile.csv
select table_name, tablespace_name
from all_tables
where owner = 'SYS'
and tablespace_name is not null;
Output will be like:
TABLE_PRIVILEGE_MAP ,SYSTEM
SYSTEM_PRIVILEGE_MAP...
JOIN queries vs multiple queries
...han several queries? (You run your main query, and then you run many other SELECTs based on the results from your main query)
...
Find nearest value in numpy array
...section give the interval properly.
array = np.arange(100000)
val = array[50000]+0.55
print( bisection(array,val))
%timeit bisection(array,val)
print( find_nearest1(array,val))
%timeit find_nearest1(array,val)
print( find_nearest2(array,val))
%timeit find_nearest2(array,val)
print( find_nearest3(ar...
NTFS performance and large volumes of files and directories
... 8084 8228 6210 6194
20000 4.30 8049 8343 5536 6100
50000 4.70 7468 7607 5364 5365
And this is the Test Code:
[TestCase(50000, false, Result = 50000)]
[TestCase(50000, true, Result = 50000)]
public static int TestDirPerformance(int numFilesInDir, bool testDirs...
PHP append one array to another (not array_push or +)
...nate without array_merge, for avoid a memory copy.
$array1 = array_fill(0,50000,'aa');
$array2 = array_fill(0,100,'bb');
// Test 1 (array_merge)
$start = microtime(true);
$r1 = array_merge($array1, $array2);
echo sprintf("Test 1: %.06f\n", microtime(true) - $start);
// Test2 (avoid copy)
$start =...
C# switch statement limitations - why?
...values of switch labels are distinct (so that only one switch block can be selected for a given switch-expression)
Consider this code example in the hypothetical case that non-constant case values were allowed:
void DoIt()
{
String foo = "bar";
Switch(foo, foo);
}
void Switch(String val1...
Locate current file in IntelliJ
...ecause you followed a reference to java.io.File.
The keymap defines it as Select current file or symbol in any view.
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WinDbg基础资料（日本語） - IT优秀资料 - 清泛网 - 专注C/C++及内核技术
...ックする、
「Atach to Process」画面の「Atach to」の「Select..」ボタンをクリックする。
「Select Code Type」画面で、「Debug these code type:」のRadio BoxをCheck ONにして、
「Managed」と「Native」をCheck ONにして、OKボタンで画...
Filter data.frame rows by a logical condition
...
To select rows according to one 'cell_type' (e.g. 'hesc'), use ==:
expr[expr$cell_type == "hesc", ]
To select rows according to two or more different 'cell_type', (e.g. either 'hesc' or 'bj fibroblast'), use %in%:
expr[expr$...
Count number of occurences for each unique value
...
This works for me. Take your vector v
length(summary(as.factor(v),maxsum=50000))
Comment: set maxsum to be large enough to capture the number of unique values
or with the magrittr package
v %>% as.factor %>% summary(maxsum=50000) %>% length
...