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Is there a max array length limit in C++?
...ypically takes multiple times as much memory as an array of type vector<char> (minus a small constant value), since int is usually bigger than char. Therefore, a vector<char> may contain more items than a vector<int> before memory is full. The same counts for raw C-style arrays lik...
What is the maximum length of a Push Notification alert text?
...me experiments.
Alerts: Prior to iOS 7, the alerts display limit was 107 characters. Bigger messages were truncated and you would get a "..." at the end of the displayed message. With iOS 7 the limit seems to be increased to 235 characters. If you go over 8 lines your message will also get truncat...
How to sort a dataFrame in python pandas by two or more columns?
... pd.DataFrame(np.random.randint(1, 5, (10,2)), columns=['a','b'])
df1 = pd.concat([df1]*100000)
def pdsort(df1):
return df1.sort_values(['a', 'b'], ascending=[True, False])
def lex(df1):
arr = df1.values
return pd.DataFrame(arr[np.lexsort((-arr[:, 1], arr[:, 0]))])
assert (pdsort(df1)...
Maximum MIMEType Length when storing type in DB
...s", type (eg. "application") and subtype (eg "vnd...") both can be max 127 characters. You do the math :)
Edit: Meanwhile, that document has been obsoleted by RFC 6838, which does not alter the maximum size but adds a remark:
Also note that while this syntax allows names of up to 127
characte...
C++使用OLE/COM高速读写EXCEL的源码 - C/C++ - 清泛网 - 专注C/C++及内核技术
...ad = FALSE);
///通过名称使用某个sheet，
BOOL LoadSheet(const TCHAR* sheet,BOOL pre_load = FALSE);
///通过序号取得某个Sheet的名称
CString GetSheetName(long table_index);
///得到Sheet的总数
int GetSheetCount();
///打开文件
BOOL OpenExcelFile(const TCHAR...
How to check for a valid Base64 encoded string
...s pretty easy to recognize a Base64 string, as it will only be composed of characters 'A'..'Z', 'a'..'z', '0'..'9', '+', '/' and it is often padded at the end with up to three '=', to make the length a multiple of 4. But instead of comparing these, you'd be better off ignoring the exception, if it o...
How to access pandas groupby dataframe by key
...ionally - turn it all back into a single dataframe object
sampled_df = pd.concat(df_list, axis=0, join='outer')
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How do you compare structs for equality in C?
...use memcmp to compare structs for equality due to potential random padding characters between field in structs.
// bad
memcmp(&struct1, &struct2, sizeof(struct1));
The above would fail for a struct like this:
typedef struct Foo {
char a;
/* padding */
double d;
/* padding */
...
Is there any difference between GROUP BY and DISTINCT
...s. Use GROUPY BY if you want to apply aggregate operators (MAX, SUM, GROUP_CONCAT, ..., or a HAVING clause).
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How to find current transaction level?
... SET
ansi_padding SET
ansi_nulls SET
concat_null_yields_null SET
isolation level read committed
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