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Remove columns from dataframe where ALL values are NA
...tion(x)!all(is.na(x))))),with=F]
examples using large data (30 columns, 1e6 rows)
big_data <- replicate(10, data.frame(rep(NA, 1e6), sample(c(1:8,NA),1e6,T), sample(250,1e6,T)),simplify=F)
bd <- do.call(data.frame,big_data)
names(bd) <- paste0('X',seq_len(30))
DT <- as.data.table(bd)
...
How to fix Git error: object file is empty?
...blob e89896b1282fbae6cf046bf21b62dd275aaa32f4
dangling blob dd09f7f1f033632b7ef90876d6802f5b5fede79a
missing blob caab8e3d18f2b8c8947f79af7885cdeeeae192fd
missing blob e4cf65ddf80338d50ecd4abcf1caf1de3127c229
Step 5: Try git reflog. Fail because my HEAD is broken.
nathanvan@nathanvan-N61Jq:~/wor...
gradle build fails on lint task
...e inspiration from
https://android.googlesource.com/platform/tools/base/+/e6a5b9c7c1bca4da402de442315b5ff1ada819c7
(implementation:
https://android.googlesource.com/platform/tools/base/+/e6a5b9c7c1bca4da402de442315b5ff1ada819c7/build-system/gradle/src/main/groovy/com/android/build/gradle/interna...
How to get the size of a JavaScript object?
... Shallow size seems as 40 for both of { a:"55c2067aee27593c03b7acbe", b:"55c2067aee27593c03b7acbe", c:null, d:undefined } and { c:null, d:undefined } objects. Is it OK?
– efkan
Apr 4 '17 at 14:58
...
Auto layout constraints issue on iOS7 in UITableViewCell
...ne but the 3 new are added "<NSAutoresizingMaskLayoutConstraint:0x8b79740 h=-&- v=-&- UITableViewCellContentView:0x8b44010.height == UITableViewCellScrollView:0x8b4a130.height>", "<NSAutoresizingMaskLayoutConstraint:0x8b7b9f0 h=-&- v=-&- UITableViewCellScrollView:0x...
App Inventor 2 蓝牙遥控教程 - 经典蓝牙与BLE控制智能硬件 · App Inventor 2 中文网
...b5-459e-8fcc-c5c9c331914b"
#define CHARACTERISTIC_UUID "beb5483e-36e1-4688-b7f5-ea07361b26a8"
BLEServer *pServer = NULL;
BLECharacteristic *pCharacteristic = NULL;
bool deviceConnected = false;
class MyServerCallbacks : public BLEServerCallbacks {
void onConnect(BLEServer *pServer) {
deviceC...
Windbg Step 2 分析程序堆栈实战 - 更多技术 - 清泛网 - 专注C/C++及内核技术
...7680000 ntdll (pdb symbols) c:\websymbols\wntdll.pdb\ACE318E6A2F44F23A6CC5628F10A7DDC2\wntdll.pdb
我们发现MSVCR90D的pdb并没有被加载，是因为程序还没运行到，
3. 按F11
没有跳到源代码！
运行：src.path C:\Program Files (x86)\Microsoft Visual Studio 9...
Numpy - add row to array
...lock
print('numpy 1.14 takes {:.3f} micros per row'.format(duration * 1e6 / n_loops))
start_clock = perf_counter()
for count in range(0, n_loops):
py_array.append(py_row) # .15 micros
numpy_array = np.array(py_array) # 43.9 micros
duration = perf_counter() - start...
MySQL “Group By” and “Order By”
... answered Mar 21 '12 at 0:45
b7kichb7kich
4,14233 gold badges2424 silver badges2626 bronze badges
...
How to sort git tags by version string order of form rc-X.Y.Z.W?
... 2016)
tag: do not show ambiguous tag names as "tags/foo"
Since b7cc53e (tag.c: use 'ref-filter' APIs, 2015-07-11), git tag has started showing tags with ambiguous names (i.e., when both "heads/foo" and "tags/foo" exists) as "tags/foo" instead of just "foo".
This is both:
pointl...