大约有 40,000 项符合查询结果（耗时：0.0674秒） [XML]
Check if an array is empty or exists
...y" !== "array"
typeof array == "undefined"; // => true
Case Null
Generally speaking, null is state of lacking a value. For example a variable is null when you missed or failed to retrieve some data.
array = searchData(); // can't find anything
array == null; // => true
Case Not a...
How to use Session attributes in Spring-mvc
...ntage:
@session may use more memory in cloud systems it copies session to all nodes, and direct method (1 and 5) has messy approach, it is not good to unit test.
To access session jsp
<%=session.getAttribute("ShoppingCart.prop")%>
in Jstl :
<c:out value="${sessionScope.ShoppingCart.p...
Is there an eval() function in Java? [duplicate]
...to do some math seems like a huge waste. But you're right, it works, especially if efficiency isn't a priority.
– Sasha Chedygov
Apr 9 '10 at 4:21
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In Javascript, how to conditionally add a member to an object?
I would like to create an object with a member added conditionally.
The simple approach is:
22 Answers
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How to round up the result of integer division?
...ause it only uses it once, you don't need to store the recordsPerPage specially if it comes from an expensive function to fetch the value from a config file or something.
I.e. this might be inefficient, if config.fetch_value used a database lookup or something:
int pageCount = (records + config.f...
Iterating over every two elements in a list
... y in pairwise(l):
print "%d + %d = %d" % (x, y, x + y)
Or, more generally:
from itertools import izip
def grouped(iterable, n):
"s -> (s0,s1,s2,...sn-1), (sn,sn+1,sn+2,...s2n-1), (s2n,s2n+1,s2n+2,...s3n-1), ..."
return izip(*[iter(iterable)]*n)
for x, y in grouped(l, 2):
print...
SQLite - increase value by a certain number
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Sample 1 (for all rows):
UPDATE Products SET Price = Price + 50
Sample 2 (for a specific row):
UPDATE Products SET Price = Price + 50 WHERE ProductID = 1
Sample 3 (generic):
UPDATE {Table} SET {Column} = {Column} + {Value} WHERE {Co...
IEnumerable to string [duplicate]
... across this before, but I have now and am surprised that I can't find a really easy way to convert an IEnumerable<char> to a string .
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Are +0 and -0 the same?
...thmetic, −0 = +0 = 0. However, in computing, some number representations allow for the existence of two zeros, often denoted by −0 (negative zero) and +0 (positive zero). This occurs in some signed number representations for integers, and in most floating point number representations. The number...
How to get milliseconds from LocalDateTime in Java 8
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Sure, if all you need is seconds, not milliseconds.
– Stuart Marks
May 30 '14 at 17:23
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