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How to check status of PostgreSQL server Mac OS X
...using psql to run a simple query and checking the exit code, e.g. psql -c 'SELECT 1', or use pg_isready to check the connection status.
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Aggregate / summarize multiple variables per group (e.g. sum, mean)
...-date), sum)
# summarising a specific set of non-grouping variables using select_helpers
# see ?select_helpers for more options
df2 <- df1 %>% group_by(year, month) %>% summarise_at(vars(starts_with('x')), sum)
df2 <- df1 %>% group_by(year, month) %>% summarise_at(vars(matches('.*...
How do I use WebStorm for Chrome Extension Development?
...ript > Libraries
Click Download
Make sure TypeScript community stubs is selected
Select chrome from the list (you can find it quickly by just typing chrome)
Click Download and Install
Click OK to close the Settings dialog.
Steps 2-6 illustrated below:
In Subsequent Projects
In any subse...
anchor jumping by using javascript
... element. If you want to get the first element out from your query, do $(mySelector)[0].scrollIntoView().
– Derek 朕會功夫
Jun 8 '18 at 12:48
4
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What do the arrow icons in Subclipse mean?
... the following buttons:
- Synchronizes the local copy with the currently selected repository when clicked. Selecting from the drop-down allows switching between different remote code bases.
- Shows only incoming changes (remote → local).
- Shows only outgoing changes (local → remote).
- Sho...
Best way to do Version Control for MS Excel
...to run these macros. In the code viewer, right click on "ThisWorkbook" and select "View Code". You may have to pull down the select box at the top of the code window to change from "(General)" view to "Workbook" view.
Contents of "Workbook" view:
Private Sub Workbook_Open()
ImportCodeModules
End...
How to speed up insertion performance in PostgreSQL
...rypto module) is (a lot) faster than uuid_generate_v4()
=# explain analyze select uuid_generate_v4(),* from generate_series(1,10000);
QUERY PLAN
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Drawing an image from a data URL to a canvas
...
in javascript , using jquery for canvas id selection :
var Canvas2 = $("#canvas2")[0];
var Context2 = Canvas2.getContext("2d");
var image = new Image();
image.src = "images/eye.jpg";
Context2.drawImage(image, 0, 0);
html5:
<canv...
选中CListCtrl指定行并发送LVN_ITEMCHANGED消息 - C/C++ - 清泛网 - 专注C/C++及内核技术
...Report.EnsureVisible(nIndex,FALSE);
m_listReport.SetItemState(nIndex,LVIS_SELECTED,LVIS_SELECTED);
但这远远不能满足需要，因为这种定位不具有在指定行上面鼠标单击选中的效果，为此我们需要向CListCtrl控件发送LVN_ITEMCHANGED消息，LVN_ITEMCHANGED是C...
CGridCtrl 选中一行 - C/C++ - 清泛网 - 专注C/C++及内核技术
CGridCtrl 选中一行 选中单元格m_Grid.SetItemState(row,col,LVIS_SELECTED|LVIS_FOCUSED); 取消选中单元格m_Grid.SetItemState(row,col,LVIS_OVERLAYMASK);//选中单元格
m_Grid.SetItemState(row, col, LVIS_SELECTED | LVIS_FOCUSED);
//取消选中单元格
m_Grid.SetItemState(row, col...