大约有 40,000 项符合查询结果（耗时：0.0448秒） [XML]
Is it better to return null or empty collection?
...r it's IEnumerable or ICollection doesn't matter that much. Anyway, if you select something of type ICollection they also return null... I would like them to return an empty collection, but I ran into them returning null, so I thought I'd just mention it here. I would say the default of a collection...
#ifdef replacement in the Swift language
...what I wanted by using custom Build Configurations:
Go to your project / select your target / Build Settings / search for Custom Flags
For your chosen target set your custom flag using -D prefix (without white spaces), for both Debug and Release
Do above steps for every target you have
Here's ...
Add a column with a default value to an existing table in SQL Server
...1), (2); alter table blah add b int null constraint df_blah_b default (0); select * from blah; You will see 2 NULL values for column b.
– ErikE
Jun 14 '13 at 22:19
48
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Get Enum from Description attribute [duplicate]
...ds = type.GetFields();
var field = fields
.SelectMany(f => f.GetCustomAttributes(
typeof(DescriptionAttribute), false), (
f, a) => new { Field = f, Att = a })
.Where(a => ((De...
Deleting DataFrame row in Pandas based on column value
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Good update for query. It allows for more rich selection criteria (eg. set-like operations like df.query('variable in var_list') where 'var_list' is a list of desired values)
– philE
Sep 30 '14 at 20:32
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Copy object values in Visual Studio debug mode
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You can add a watch for that object, and in the watch window, expand and select everything you want to copy and then copy it.
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One-liner to take some properties from object in ES 6
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Why do you use hasOwnProperty? If the fields are hand-selected, even in seems to be more appropriate; although I'd go for omitting the check completely and just let them default to undefined.
– Bergi
Nov 24 '15 at 0:19
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How can I pass a parameter to a setTimeout() callback?
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I'm not sure why this answer wasn't selected as the best. Using an anonymous function works, sure, but if you can simply pass a third parameter into the original setTimeout function call... why not?
– Kris Schouw
Sep 21 '1...
Deleting lines from one file which are in another file
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grep -v -x -f f2 f1 should do the trick.
Explanation:
-v to select non-matching lines
-x to match whole lines only
-f f2 to get patterns from f2
One can instead use grep -F or fgrep to match fixed strings from f2 rather than patterns (in case you want remove the lines in a "what you...
Simultaneously merge multiple data.frames in a list
... c 3 5 7
We don't have to take all columns, we can use select helpers from tidyselect and
choose (as we start from .x all .x columns are kept):
eat(x, list(y,z), starts_with("l") ,.by = "i")
# # A tibble: 3 x 3
# i j l
# <chr> <int> <int>
# 1 a ...