大约有 47,000 项符合查询结果（耗时：0.0399秒） [XML]
find without recursion
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Rob Bednark
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answered Oct 13 '10 at 15:35
eldarerathiseldarer...
How to rename items in values() in Django?
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answered May 15 '12 at 10:45
Daniel RosemanDaniel Roseman
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Select first 4 rows of a data.frame in R
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156
Use head:
dnow <- data.frame(x=rnorm(100), y=runif(100))
head(dnow,4) ## default is 6
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Can PostgreSQL index array columns?
...CREATE TABLE "Test"("Column1" int[]);
INSERT INTO "Test" VALUES ('{10, 15, 20}');
INSERT INTO "Test" VALUES ('{10, 20, 30}');
CREATE INDEX idx_test on "Test" USING GIN ("Column1");
-- To enforce index usage because we have only 2 records for this test...
SET enable_seqscan TO ...
Failed to build gem native extension (installing Compass)
... on Ubuntu 14.04 LTS
– thomh
Feb 4 '15 at 16:01
30
Worked on CentOS with "yum install ruby-devel"...
How to add new item to hash
... the value !
– maguri
Apr 10 '18 at 15:15
3
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Calculate difference between two datetimes in MySQL
... can use:
SELECT TIMESTAMPDIFF(SECOND, '2012-06-06 13:13:55', '2012-06-06 15:20:18')
In your case, the third parameter of TIMSTAMPDIFF function would be the current login time (NOW()). Second parameter would be the last login time, which is already in the database.
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Get the client's IP address in socket.io
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edited Sep 25 '15 at 14:19
Balthazar
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Sleeping in a batch file
...beard is outBlorgbeard is out
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RegEx backreferences in IntelliJ
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Seems like "\" is not required: jetbrains.com/idea/help/…. Also, for me it works only if I explicitly surround my group with "()", otherw...