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MFC CString::Format()函数详解 - C/C++ - 清泛网 - 专注C/C++及内核技术
...殊意义，比如"%6s"
格式指令具有以下的形式：
"%" [index ":"] ["-"] [width] ["." prec] type
它是以"%"开始,而以type结束，type表示一个具体的类型。中间是用来格式化type类型的指令字符，是可选的。
先来看看type,type可以是以下...
When should I use the HashSet type?
...id Clear();
bool Contains(T item);
void CopyTo(T[] array, int arrayIndex);
bool Remove(T item);
// Properties
int Count { get; }
bool IsReadOnly { get; }
}
A List<T> implements IList<T>, which extends the ICollection<T>
public interface IList<T> : IC...
Pandas get topmost n records within each group
...
EDIT: As mentioned by the questioner, use df.groupby('id').head(2).reset_index(drop=True) to remove the multindex and flatten the results.
>>> df.groupby('id').head(2).reset_index(drop=True)
id value
0 1 1
1 1 2
2 2 1
3 2 2
4 3 1
5 4 1
...
Hash Map in Python
... self.store = [None for _ in range(16)]
def get(self, key):
index = hash(key) & 15
if self.store[index] is None:
return None
n = self.store[index]
while True:
if n.key == key:
return n.value
else:
...
Custom Cell Row Height setting in storyboard is not responding
... this method:
- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath;
In the function of a row you can choose Height. For example,
- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath
{
if (indexPath.row == 0) ...
How to avoid passing parameters everywhere in play2?
...
Then in your actions you’ll be able to just write the following:
def index = Action {
Ok(views.html.index())
}
def index2 = Action {
Ok(views.html.index2())
}
You can find more information about this approach in this blog post and in this code sample.
Update: A nice blog post demonstra...
Quick easy way to migrate SQLite3 to MySQL? [closed]
...nes starting with:
BEGIN TRANSACTION
COMMIT
sqlite_sequence
CREATE UNIQUE INDEX
are not used in MySQL
SQLite uses CREATE TABLE/INSERT INTO "table_name" and MySQL uses CREATE TABLE/INSERT INTO table_name
MySQL doesn't use quotes inside the schema definition
MySQL uses single quotes for strings ins...
How to create a sub array from another array in Java?
...to create a sub-array from another array? Is there a method that takes the indexes from the first array such as:
9 Answers
...
Storing sex (gender) in database
... a need to port.
Conclusion
I would use Option 2: CHAR(1).
Addendum
An index on the gender column likely would not help because there's no value in an index on a low cardinality column. Meaning, there's not enough variety in the values for the index to provide any value.
...
How to COUNT rows within EntityFramework without loading contents?
...ce SQL Server really can't do anything but do a full table scan (clustered index scan).
Sometimes, it's good enough to know an approximate number of rows from the database, and in such a case, a statement like this might suffice:
SELECT
SUM(used_page_count) * 8 AS SizeKB,
SUM(row_count) ...