大约有 6,000 项符合查询结果（耗时：0.0198秒） [XML]
SQL query for finding records where count > 1
...p int(11) not null,
dt date not null
);
insert into payment values
(1,123,55555,'2009-12-12'),
(1,123,66666,'2009-12-12'),
(1,123,77777,'2009-12-13'),
(2,456,77777,'2009-12-14'),
(2,456,77777,'2009-12-14'),
(2,789,77777,'2009-12-14'),
(2,789,77777,'2009-12-14');
select foo.user_id, foo.cnt fro...
How to move a file?
I looked into the Python os interface, but was unable to locate a method to move a file. How would I do the equivalent of $ mv ... in Python?
...
How to retrieve a module's path?
...tually give you the path to the .pyc file that was loaded, at least on Mac OS X. So I guess you can do:
import os
path = os.path.abspath(a_module.__file__)
You can also try:
path = os.path.dirname(a_module.__file__)
To get the module's directory.
...
Using Python's os.path, how do I go up one directory?
...
os.path.abspath(os.path.join(os.path.dirname( __file__ ), '..', 'templates'))
As far as where the templates folder should go, I don't know since Django 1.4 just came out and I haven't looked at it yet. You should probably a...
Remove duplicated rows using dplyr
...ction for this purpose.
Original answer below:
library(dplyr)
set.seed(123)
df <- data.frame(
x = sample(0:1, 10, replace = T),
y = sample(0:1, 10, replace = T),
z = 1:10
)
One approach would be to group, and then only keep the first row:
df %>% group_by(x, y) %>% filter(row_nu...
What is the iPad user agent?
From what I gather, the iPad is using iPhone OS, but with a different screen resolution from the iPhone and iPod touch. So many sites may have to change their user agent detection to adapt to the iPad.
...
Checking if a string can be converted to float in Python
... ------------
print(isfloat("")) False
print(isfloat("1234567")) True
print(isfloat("NaN")) True nan is also float
print(isfloat("NaNananana BATMAN")) False
print(isfloat("123.456")) True
print(isfloat("123.E4")) ...
Getting file size in Python? [duplicate]
...
Use os.path.getsize(path) which will
Return the size, in bytes, of path. Raise OSError if the file does not exist or is inaccessible.
import os
os.path.getsize('C:\\Python27\\Lib\\genericpath.py')
Or use os.stat(path).st_...
What does the “yield” keyword do?
...one, etc. And generators return... well that's where yield comes in:
def f123():
yield 1
yield 2
yield 3
for item in f123():
print item
Instead of yield statements, if you had three return statements in f123() only the first would get executed, and the function would exit. But f1...
Dynamic SQL - EXEC(@SQL) versus EXEC SP_EXECUTESQL(@SQL)
...
EXEC('SELECT * FROM FOO WHERE ID=?', 123) will replace the parameter placeholder "?" with the value 123 and then execute the query, returning a result for SELECT * FROM FOO WHERE ID=123
– Peter Wone
Jun 1 '10 at 23:27
...