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Creating a “logical exclusive or” operator in Java
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Java does have a logical XOR operator, it is ^ (as in a ^ b).
Apart from that, you can't define new operators in Java.
Edit: Here's an example:
public static void main(String[] args) {
boolean[] all = { false, true };
for (boolean a : all) {
for (boolean b: all) ...
assign multiple variables to the same value in Javascript
I have initialized several variables in the global scope in a JavaScript file:
5 Answers
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How to count the frequency of the elements in an unordered list?
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Note: You should sort the list before using groupby.
You can use groupby from itertools package if the list is an ordered list.
a = [1,1,1,1,2,2,2,2,3,3,4,5,5]
from itertools import groupby
[len(list(group)) for key, group in groupby(a)]
Output:
[4, 4...
Android微信智能心跳方案 - 更多技术 - 清泛网 - 专注C/C++及内核技术
...心跳就可以很大程度的保证下一次心跳环境是正常的。
b）成功一次认定，失败连续累积认定：成功是绝对的，连续失败多次才可能是失败。
c）临界值避免：我们使用比计算出的心跳稍微小一点的值做为稳定心跳避免临界值。...
Remove an item from a dictionary when its key is unknown
What is the best way to remove an item from a dictionary by value, i.e. when the item's key is unknown? Here's a simple approach:
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Is there a difference between using a dict literal and a dict constructor?
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I think you have pointed out the most obvious difference. Apart from that,
the first doesn't need to lookup dict which should make it a tiny bit faster
the second looks up dict in locals() and then globals() and the finds the builtin, so you can switch the beh...
Assign pandas dataframe column dtypes
... I've had to manually parse into a list of lists, as the file was not amenable for pd.read_csv )
6 Answers
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How to test if list element exists?
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This is actually a bit trickier than you'd think. Since a list can actually (with some effort) contain NULL elements, it might not be enough to check is.null(foo$a). A more stringent test might be to check that the name is actually defined in t...
How do I concatenate strings in Swift?
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You can concatenate strings a number of ways:
let a = "Hello"
let b = "World"
let first = a + ", " + b
let second = "\(a), \(b)"
You could also do:
var c = "Hello"
c += ", World"
I'm sure there are more ways too.
Bit of description
let creates a con...
Find size of Git repository
... git 1.8.3 introduced a more efficient way to get a rough size: git count-objects -vH (see answer by @VonC)
For different ideas of "complete size" you could use:
git bundle create tmp.bundle --all
du -sh tmp.bundle
Close (but not exact:)
git gc
du -sh .git/
With the latter, you would also be...