大约有 13,330 项符合查询结果（耗时：0.0337秒） [XML]
How to redirect 404 errors to a page in ExpressJS?
...low,
// this means that Express will attempt
// to match & call routes _before_ continuing
// on, at which point we assume it's a 404 because
// no route has handled the request.
app.use(app.router);
// Since this is the last non-error-handling
// middleware use()d, we assume 404, as nothing e...
How to use if - else structure in a batch file?
...at least was) DOS!
@echo off
set one=1
set two=2
REM Example 1
IF %one%_%two%==1_1 (
echo Example 1 fails
) ELSE IF %one%_%two%==1_2 (
echo Example 1 works correctly
) ELSE (
echo Example 1 fails
)
REM Example 2
set test1result=0
set test2result=0
if %one%==1 if %two%==1 set test1re...
Cleaner way to update nested structures
...ss, and an address in a person:
val addressZipCodeLens = Lens(
get = (_: Address).zipCode,
set = (addr: Address, zipCode: Int) => addr.copy(zipCode = zipCode))
val personAddressLens = Lens(
get = (_: Person).address,
set = (p: Person, addr: Address) => p.copy(address = addr)...
Convert a row of a data frame to vector
...u have to be careful if your row contains a factor. Here is an example:
df_1 = data.frame(V1 = factor(11:15),
V2 = 21:25)
df_1[1,] %>% as.numeric() # you expect 11 21 but it returns
[1] 1 21
Here is another example (by default data.frame() converts characters to factors)
d...
How to get last items of a list in Python?
...
a negative index will count from the end of the list, so:
num_list[-9:]
share
|
improve this answer
|
follow
|
...
Can you find all classes in a package using reflection?
...0, file.getName().length() - 6)));
}
}
return classes;
}
__________
1 This method was taken originally from http://snippets.dzone.com/posts/show/4831, which was archived by the Internet Archive, as linked to now. The snippet is also available at https://dzone.com/articles/get-all-c...
Include all existing fields and add new fields to document
...s the new fields.
db.collection.aggregate([
{ "$addFields": { "custom_field": "$obj.obj_field1" } }
])
share
|
improve this answer
|
follow
|
...
How can I check if a string represents an int, without using try/except?
...0' format, which is similar to int casting in this sense.
edit:
def check_int(s):
if s[0] in ('-', '+'):
return s[1:].isdigit()
return s.isdigit()
share
|
improve this answer
...
Virtual Memory Usage from Java under Linux, too much memory used
...6-x64/jre/lib/amd64/libjava.so
...
00007fa1f34aa000 1576K r-x-- /lib/x86_64-linux-gnu/libc-2.13.so
00007fa1f3634000 2044K ----- /lib/x86_64-linux-gnu/libc-2.13.so
00007fa1f3833000 16K r-x-- /lib/x86_64-linux-gnu/libc-2.13.so
00007fa1f3837000 4K rwx-- /lib/x86_64-linux-gnu/libc-2.13....
How to convert a string to utf-8 in Python
...
In Python 2
>>> plain_string = "Hi!"
>>> unicode_string = u"Hi!"
>>> type(plain_string), type(unicode_string)
(<type 'str'>, <type 'unicode'>)
^ This is the difference between a byte string (plain_string) and a unic...