大约有 40,000 项符合查询结果（耗时：0.0207秒） [XML]
How do I add the contents of an iterable to a set?
...
@eipxen: There's | for union, & for intersection, and ^ for getting elements that are in one or the other but not both. But in a dynamically typed language where it's sometimes difficult to read the code and know the types of objects flying aro...
SQL NVARCHAR and VARCHAR Limits
... large (unavoidable) dynamic SQL query. Due to the number of fields in the selection criteria the string containing the dynamic SQL is growing over 4000 chars. Now, I understand that there is a 4000 max set for NVARCHAR(MAX) , but looking at the executed SQL in Server Profiler for the statement
...
Find a string by searching all tables in SQL Server Management Studio 2008
...T NULL
BEGIN
SET @ColumnName = ''
SET @TableName =
(
SELECT MIN(QUOTENAME(TABLE_SCHEMA) + '.' + QUOTENAME(TABLE_NAME))
FROM INFORMATION_SCHEMA.TABLES
WHERE TABLE_TYPE = 'BASE TABLE'
AND QUOTENAME(TABLE_SCHEMA) + '.' + QUOTENAME(TABLE_N...
MySQL error: key specification without a key length
...d, and the trick is to choose a number N that’s long enough to give good selectivity, but short enough to save space. The prefix should be long enough to make the index nearly as useful as it would be if you’d indexed the whole column.
Before we go further let us define some important terms. In...
How do I filter ForeignKey choices in a Django ModelForm?
...tions = super(FrontEndAdmin, self).get_actions(request)
if 'delete_selected' in actions:
del actions['delete_selected']
return actions
prevents delete permission
def has_delete_permission(self, request, obj=None):
return False
filters objects that can be ...
How can I validate a string to only allow alphanumeric characters in it?
...n I validate a string using Regular Expressions to only allow alphanumeric characters in it?
10 Answers
...
What platforms have something other than 8-bit char?
Every now and then, someone on SO points out that char (aka 'byte') isn't necessarily 8 bits .
12 Answers
...
Get difference between two lists
...the following simple function.
def diff(list1, list2):
c = set(list1).union(set(list2)) # or c = set(list1) | set(list2)
d = set(list1).intersection(set(list2)) # or d = set(list1) & set(list2)
return list(c - d)
or
def diff(list1, list2):
return list(set(list1).symmetric_d...
getting type T from IEnumerable
... t.GetGenericTypeDefinition() == typeof(IEnumerable<>))
.Select(t => t.GetGenericArguments()[0]);
}
Some objects implement more than one generic IEnumerable so it is necessary to return an enumeration of them.
Edit: Although, I have to say, it's a terrible idea for a class to...
Calculate a MD5 hash from a string
... (
Encoding.UTF8.GetBytes(observedText)
)
select ba.ToString("x2")
);
}
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