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(![]+[])[+[]]… Explain why this works
...e second operand of the addition, an empty Array, [], this is made just to convert the false value to String, because the string representation of an empty array is just an empty string, is equivalent to:
false+[]; // "false"
false+''; // "false"
The last part, the pair of square brackets after t...
Combine two columns of text in pandas dataframe
...arter"]
If one (or both) of the columns are not string typed, you should convert it (them) first,
df["period"] = df["Year"].astype(str) + df["quarter"]
Beware of NaNs when doing this!
If you need to join multiple string columns, you can use agg:
df['period'] = df[['Year', 'quarter', ...]].a...
How to get Scala List from Java List?
...
EDIT: Note that this is deprecated since 2.12.0. Use JavaConverters instead. (comment by @Yaroslav)
Since Scala 2.8 this conversion is now built into the language using:
import scala.collection.JavaConversions._
...
lst.toList.foreach{ node => .... }
works. asScala did not ...
How to filter specific apps for ACTION_SEND intent (and set a different text for each app)
...(intent, packageName, ri.loadLabel(pm), ri.icon));
}
}
// convert intentList to array
LabeledIntent[] extraIntents = intentList.toArray( new LabeledIntent[ intentList.size() ]);
openInChooser.putExtra(Intent.EXTRA_INITIAL_INTENTS, extraIntents);
startActivity(openInChoo...
About “*.d.ts” in TypeScript
...of file is something like "head file" in C++ but for JS only. But I cannot convert a pure JS file to *.d.ts file unless I forcely change the *.js to *.ts . So I have three files:
a JS file, a TS file and a *.d.ts file.
...
How to Calculate Execution Time of a Code Snippet in C++
...HighDateTime;
uint64 ret = li.QuadPart;
ret -= 116444736000000000LL; /* Convert from file time to UNIX epoch time. */
ret /= 10000; /* From 100 nano seconds (10^-7) to 1 millisecond (10^-3) intervals */
return ret;
#else
/* Linux */
struct timeval tv;
gettimeofday(&tv, NULL);
uint64 ...
Why doesn't c++ have &&= or ||= for booleans?
...different value such as 2. When assigning that value to a bool, it will be converted to true as per the standard.
The only way to get an invalid value into a bool is by using reinterpret_cast on pointers:
int i = 2;
bool b = *reinterpret_cast<bool*>(&i);
b |= true; // MAY yield 3 (but do...
Storing Objects in HTML5 localStorage
...vaScript object in HTML5 localStorage , but my object is apparently being converted to a string.
22 Answers
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data.frame rows to a list
I have a data.frame which I would like to convert to a list by rows, meaning each row would correspond to its own list elements. In other words, I would like a list that is as long as the data.frame has rows.
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Where did the name `atoi` come from?
In the C language where did they come up with the name atoi for converting a string to an integer? The only thing I can think of is Array To Integer for an acronym but that doesn't really make sense.
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