大约有 43,100 项符合查询结果（耗时：0.0372秒） [XML]
Abort makefile if variable not set
... all have non-empty values,
# die with an error otherwise.
#
# Params:
# 1. Variable name(s) to test.
# 2. (optional) Error message to print.
check_defined = \
$(strip $(foreach 1,$1, \
$(call __check_defined,$1,$(strip $(value 2)))))
__check_defined = \
$(if $(value $1),, \
...
How to remove the first Item from a list?
I have the list [0, 1, 2, 3, 4] I'd like to make it into [1, 2, 3, 4] . How do I go about this?
10 Answers
...
How to find the length of a string in R
...
See ?nchar. For example:
> nchar("foo")
[1] 3
> set.seed(10)
> strn <- paste(sample(LETTERS, 10), collapse = "")
> strn
[1] "NHKPBEFTLY"
> nchar(strn)
[1] 10
share
|...
Cosine Similarity between 2 Number Lists
...te the cosine similarity between two lists , let's say for example list 1 which is dataSetI and list 2 which is dataSetII . I cannot use anything such as numpy or a statistics module. I must use common modules (math, etc) (and the least modules as possible, at that, to reduce time spent).
...
How to get the first and last date of the current year?
...
18 Answers
18
Active
...
What's the better (cleaner) way to ignore output in PowerShell? [closed]
...
184
I just did some tests of the four options that I know about.
Measure-Command {$(1..1000) | Ou...
Assign output of a program to a variable using a MS batch file
...
One way is:
application arg0 arg1 > temp.txt
set /p VAR=<temp.txt
Another is:
for /f %%i in ('application arg0 arg1') do set VAR=%%i
Note that the first % in %%i is used to escape the % after it and is needed when using the above code in a batch ...
Should I use multiplication or division?
...
Python:
time python -c 'for i in xrange(int(1e8)): t=12341234234.234 / 2.0'
real 0m26.676s
user 0m25.154s
sys 0m0.076s
time python -c 'for i in xrange(int(1e8)): t=12341234234.234 * 0.5'
real 0m17.932s
user 0m16.481s
sys 0m0.048s
multiplication i...
How can I create a two dimensional array in JavaScript?
...
1
2
Next
1262
...
Converting string into datetime
...:
from datetime import datetime
datetime_object = datetime.strptime('Jun 1 2005 1:33PM', '%b %d %Y %I:%M%p')
The resulting datetime object is timezone-naive.
Links:
Python documentation for strptime: Python 2, Python 3
Python documentation for strptime/strftime format strings: Python 2, Pyth...