大约有 40,000 项符合查询结果（耗时：0.0469秒） [XML]
Changing column names of a data frame
...
Try setnames() in the data.table package. Use something like setnames(DT,"b","B") or setnames(DT,c("a","E"),c("A","F"))
– dwstu
Aug 11 '14 at 17:23
...
Remove menu and status bars in TinyMCE 4
...ne strikethrough superscript subscript | formats | removeformat'},
table: {title: 'Table', items: 'inserttable tableprops deletetable | cell row column'},
tools: {title: 'Tools', items: 'spellchecker code'}
}
});
see TinyMCE for more help.
...
COUNT DISTINCT with CONDITIONS
...tinct items in a column subject to a certain condition, for example if the table is like this:
5 Answers
...
Error 1046 No database Selected, how to resolve?
...ell MySQL which database to use:
USE database_name;
before you create a table.
In case the database does not exist, you need to create it as:
CREATE DATABASE database_name;
followed by:
USE database_name;
share
...
Postgres: How to do Composite keys?
... error, and omit the redundant CONSTRAINT (already implied), too:
CREATE TABLE tags
(
question_id INTEGER NOT NULL,
tag_id SERIAL NOT NULL,
tag1 VARCHAR(20),
tag2 VARCHAR(20),
tag3 VARCHAR(20),
PRIMARY ...
Why do my list item bullets overlap floating elements
...e CSS below to make the list work alongside the floated content.
display: table; works alongside floated content (filling the gap) but without hiding content behind it. Much like a table does :-)
.img {
float: left;
}
.table {
display: table;
}
<img class="img" src="https://via....
How do I view the full content of a text or varchar(MAX) column in SQL Server 2008 Management Studio
... this live SQL Server 2008 (build 10.0.1600) database, there's an Events table, which contains a text column named Details . (Yes, I realize this should actually be a varchar(MAX) column, but whoever set this database up did not do it that way.)
...
What is the difference between memoization and dynamic programming?
...g all related sub-problems first, typically by filling up an n-dimensional table. Based on the results in the table, the solution to the "top" / original problem is then computed.
If you use memoization to solve the problem you do it by maintaining a map of already solved sub problems. You do it "t...
Unknown column in 'field list' error on MySQL Update query
...er inside single quotes; e.g.:
$name = "my name"
$query = " INSERT INTO mytable VALUES ( 1 , '$name') "
Note that although the query is enclosed between double quotes, you must enclose any string in single quotes.
share
...
MongoDB Many-to-Many Association
...y relationship)? Even the MongoDB docs hint that you should avoid having mutable, huge arrays of references. docs.mongodb.org/manual/tutorial/…
– CaptSaltyJack
Feb 1 '15 at 20:07
...