大约有 40,000 项符合查询结果（耗时：0.0383秒） [XML]
Create list of single item repeated N times
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Create List of Single Item Repeated n Times in Python
Immutable items
For immutable items, like None, bools, ints, floats, strings, tuples, or frozensets, you can do it like this:
[e] * 4
Note that this is best only used with immutable items (strings, tuples, frozensets, ) in th...
How to implement a Map with multiple keys? [duplicate]
...nother solution is to use Google's Guava
import com.google.common.collect.Table;
import com.google.common.collect.HashBasedTable;
Table<String, String, Integer> table = HashBasedTable.create();
The usage is really simple:
String row = "a";
String column = "b";
int value = 1;
if (!table.c...
Doctrine2: Best way to handle many-to-many with extra columns in reference table
...port AppBundle yml still generate manyToMany relation for the original two tables and simply ignore the third table instead of concidering it as an entity :/
– Stphane
Mar 18 '15 at 23:24
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PostgreSQL - fetch the row which has the Max value for a column
I'm dealing with a Postgres table (called "lives") that contains records with columns for time_stamp, usr_id, transaction_id, and lives_remaining. I need a query that will give me the most recent lives_remaining total for each usr_id
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How to have an automatic timestamp in SQLite?
...
Just declare a default value for a field:
CREATE TABLE MyTable(
ID INTEGER PRIMARY KEY,
Name TEXT,
Other STUFF,
Timestamp DATETIME DEFAULT CURRENT_TIMESTAMP
);
However, if your INSERT command explicitly sets this field to NULL, it will be set to NULL.
...
Is BCrypt a good hashing algorithm to use in C#? Where can I find it? [closed]
...ing through the use of the same encryption key that encrypted it.
Rainbow Table - a lookup table that contains all variations of characters hashed in a specific hashing algorithm.
Salt - a known random string appended to the original string before it is hashed.
For the .NET Framework, Bcrypt does...
How many characters can UTF-8 encode?
...
According to this table* UTF-8 should support:
231 = 2,147,483,648 characters
However, RFC 3629 restricted the possible values, so now we're capped at 4 bytes, which gives us
221 = 2,097,152 characters
Note that a good chunk of those chara...
How does one reorder columns in a data frame?
...ec]
return(data)
}
Now the OP's request becomes as simple as this:
table <- data.frame(Time=c(1,2), In=c(2,3), Out=c(3,4), Files=c(4,5))
table
## Time In Out Files
##1 1 2 3 4
##2 2 3 4 5
arrange.vars(table, c("Out"=2))
## Time Out In Files
##1 1 3 2 4
##2...
Approximate cost to access various caches and main memory?
... ~100 ns
EDIT2:
The most important is the notice under the cited table, saying:
"NOTE: THESE VALUES ARE ROUGH APPROXIMATIONS. THEY DEPEND ON
CORE AND UNCORE FREQUENCIES, MEMORY SPEEDS, BIOS SETTINGS,
NUMBERS OF DIMMS, ETC,ETC..YOUR MILEAGE MAY VARY."
EDIT: I should highlight that...
org.hibernate.MappingException: Could not determine type for: java.util.List, at table: College, for
I'm using Hibernate for all CRUD operations in my project. It doesn't work for One-To-Many and Many-To-One relationships. It gives me the below error.
...