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What is the __DynamicallyInvokable attribute for?
...q.Enumerable in DotPeek I notice that some methods are flavoured with a [__DynamicallyInvokable] attribute.
2 Answers
...
How to add column if not exists on PostgreSQL?
...statement:
DO $$
BEGIN
BEGIN
ALTER TABLE <table_name> ADD COLUMN <column_name> <column_type>;
EXCEPTION
WHEN duplicate_column THEN RAISE NOTICE 'column <column_name> already exists in <table_name>.';
END;
END;
$$
...
How to import multiple .csv files at once?
...olutions in other answers using things like do.call(rbind,...), dplyr::bind_rows() or data.table::rbindlist().
If you really want each data frame in a separate object, even though that's often inadvisable, you could do the following with assign:
temp = list.files(pattern="*.csv")
for (i in 1:lengt...
MLKitTranslator 拓展：离线翻译 · App Inventor 2 中文网
...认 en）、一个输入框、一个按钮、一个标签。
when 按钮_翻译.Click() {
标签1.Text = "翻译中…"
MLKitTranslator1.Translate(文本输入框_输入.Text)
}
when MLKitTranslator1.GotTranslation(originalText, translatedText) {
标签1.Text = translatedText
}
when MLKitTran...
Override Python's 'in' operator?
...
MyClass.__contains__(self, item)
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导航条使用指导 · App Inventor 2 中文网
...宽度充满父级）；
拖一个标签到屏幕上方（改名 标签_标题，用来看选中结果）；
搭下面的代码块：
when Screen1.Initialize() {
导航条1.SetItems(list("", "", "", ""), list("首页", "分类", "购物车", "我的"))
}
when 导航条1.ItemSelected(索引)...
扫码寻宝 · App Inventor 2 中文网
...。
procedure 显示线索() {
if 关卡 > length(线索) {
标签_关卡.Text = "全部通关！"
标签_线索.Text = "恭喜你找到了所有宝藏！"
} else {
标签_关卡.Text = join("第 ", 关卡, " 关 / 共 ", length(线索), " 关")
标签_线索.Text = select(线...
GestureDetector 手势检测拓展：旋转、缩放和滑动手势检测，自定义手势识别...
...。
when Screen1.Initialize() {
SwipeDetector1.AddHandler(垂直布局_手势区)
}
when SwipeDetector1.SwipeLeft() {
标签_提示.Text = "向左滑：下一页"
}
when SwipeDetector1.SwipeRight() {
标签_提示.Text = "向右滑：上一页"
}
when SwipeDetector1.DoubleClick() {
标...
Setting up two different static directories in node.js Express framework
...nal (first) parameter to use() like so:
app.use("/public", express.static(__dirname + "/public"));
app.use("/public2", express.static(__dirname + "/public2"));
That way you get two different directories on the web that mirror your local directories, not one url path that fails over between two lo...
Python debugging tips [closed]
...
PDB
You can use the pdb module, insert pdb.set_trace() anywhere and it will function as a breakpoint.
>>> import pdb
>>> a="a string"
>>> pdb.set_trace()
--Return--
> <stdin>(1)<module>()->None
(Pdb) p a
'a string'
(Pdb)
To...