大约有 40,000 项符合查询结果（耗时：0.0572秒） [XML]
Primary key or Unique index?
.... Example:
CREATE TABLE table1 (foo int, bar int);
CREATE UNIQUE INDEX ux_table1_foo ON table1(foo); -- Create unique index on foo.
INSERT INTO table1 (foo, bar) VALUES (1, 2); -- OK
INSERT INTO table1 (foo, bar) VALUES (2, 2); -- OK
INSERT INTO table1 (foo, bar) VALUES (3, 1); -- OK
INSERT INTO...
Is there a better way of writing v = (v == 0 ? 1 : 0); [closed]
...
@Brian: not with that magic + sign! ¯\_(ツ)_/¯
– jAndy
Aug 2 '11 at 11:33
...
How to override and extend basic Django admin templates?
...tion has been converted to a django app, and is available in PyPi (pip/easy_install) as django-apptemplates: pypi.python.org/pypi/django-apptemplates
– Romløk
Oct 9 '12 at 9:19
9
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Use of def, val, and var in scala
...sed:
scala> something = 5 * 6
<console>:8: error: value something_= is not a member of object $iw
something = 5 * 6
^
When the class is defined like:
scala> class Person(val name: String, var age: Int)
defined class Person
and then instantiated with:
scala> def pe...
Count number of occurrences of a pattern in a file (even on same line)
...color tags it prints out:
echo -e "a\nb b b\nc\ndef\nb e brb\nr" \
| GREP_COLOR="033" grep --color=always b \
| perl -e 'undef $/; $_=<>; s/\n//g; s/\x1b\x5b\x30\x33\x33/\n/g; print $_' \
| wc -l
share
|
...
Changing UIImage color
...
Swift 4.2 Solution
extension UIImage {
func withColor(_ color: UIColor) -> UIImage {
UIGraphicsBeginImageContextWithOptions(size, false, scale)
guard let ctx = UIGraphicsGetCurrentContext(), let cgImage = cgImage else { return self }
color.setFill()
...
理解和配置 Linux 下的 OOM Killer - 操作系统(内核) - 清泛网 - 专注C/C++及内核技术
...-vm:47388kB, anon-rss:3744kB, file-rss:80kB
httpd invoked oom-killer: gfp_mask=0x201da, order=0, oom_adj=0, oom_score_adj=0
httpd cpuset=/ mems_allowed=0
Pid: 8911, comm: httpd Not tainted 2.6.32-279.1.1.el6.i686 #1
...
21556 total pagecache pages
21049 pages in swap cache
Swap cache s...
Quickly reading very large tables as dataframes
...rom csv/tab-delimited files directly into R. See mnel's answer.
Using read_table in readr (on CRAN from April 2015). This works much like fread above. The readme in the link explains the difference between the two functions (readr currently claims to be "1.5-2x slower" than data.table::fread).
r...
Google Sheets API Setup · App Inventor 2 中文网
...le you got from the Service Account setup steps.
Unable to parse range: ______
If you get this error message, there may be an error with the range that you
provided. This could mean that the sheetName you’ve provided does not actually
exist, or that the reference you provided is not valid A1-...
How to use mongoimport to import csv
...ecting to: test
> use mydb
switched to db mydb
> db.things.find()
{ "_id" : ObjectId("4d32a36ed63d057130c08fca"), "Name" : "Jane Doe", "Address" : "123 Main St", "City" : "Whereverville", "State" : "CA", "ZIP" : 90210 }
{ "_id" : ObjectId("4d32a36ed63d057130c08fcb"), "Name" : "John Doe", "Addr...