大约有 43,640 项符合查询结果（耗时：0.0342秒） [XML]
Return first N key:value pairs from dict
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edited Aug 21 '19 at 12:43
ofir_aghai
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Why does Math.round(0.49999999999999994) return 1?
....1 This is a specification bug, for precisely this one pathological case.2 Java 7 no longer mandates this broken implementation.3
The problem
0.5+0.49999999999999994 is exactly 1 in double precision:
static void print(double d) {
System.out.printf("%016x\n", Double.doubleToLongBits(d));
}
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Why does ~True result in -2?
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240
int(True) is 1.
1 is:
00000001
and ~1 is:
11111110
Which is -2 in Two's complement1
1 ...
How does the extend() function work in jQuery?
...nd works, so I ran a little test:
var a = {foo: 1, bar: 1};
var b = {foo: 2, baz: 2};
var c = {foo: 3};
var r = jQuery.extend(a,b,c);
console.log("A: Foo=" + a.foo + " Bar=" + a.bar + " Baz=" + a.baz);
console.log("B: Foo=" + b.foo + " Bar=" + b.bar + " Baz=" + b.baz);
console.log("C: Foo=" + c.foo...
Hash Map in Python
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253
Python dictionary is a built-in type that supports key-value pairs.
streetno = {"1": "Sachin ...
combinations between two lists?
...e looking for - see the other answers.
Suppose len(list1) >= len(list2). Then what you appear to want is to take all permutations of length len(list2) from list1 and match them with items from list2. In python:
import itertools
list1=['a','b','c']
list2=[1,2]
[list(zip(x,list2)) for x in ite...
Aggregate / summarize multiple variables per group (e.g. sum, mean)
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Where is this year() function from?
You could also use the reshape2 package for this task:
require(reshape2)
df_melt <- melt(df1, id = c("date", "year", "month"))
dcast(df_melt, year + month ~ variable, sum)
# year month x1 x2
1 2000 1 -80.83405 -224.9540159
2 ...
搭建高可用mongodb集群（一）——配置mongodb - 大数据 & AI - 清泛网 - 专...
...test/single/data
#进入mongodb文件夹
cd /data/mongodbtest/single
2、下载mongodb的安装程序包
wget http://fastdl.mongodb.org/linux/mongodb-linux-x86_64-2.4.6.tgz
#解压下载的压缩包
tar xvzf mongodb-linux-x86_64-2.4.6.tgz
#进入mongodb程序执行文件夹
cd mon...
New Array from Index Range Swift
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This works for me:
var test = [1, 2, 3]
var n = 2
var test2 = test[0..<n]
Your issue could be with how you're declaring your array to begin with.
EDIT:
To fix your function, you have to cast your Slice to an array:
func aFunction(numbers: Array<Int...
Git 工具 - 子模块(submodule)：一个仓库包含另一个仓库 - 开源 & Github -...
... /dev/null
+++ b/DbConnector
@@ -0,0 +1 @@
+Subproject commit c3f01dc8862123d317dd46284b05b6892c7b29bc
虽然 DbConnector 是工作目录中的一个子目录，但 Git 还是会将它视作一个子模块。当你不在那个目录中时，Git 并不会跟踪它的内容， 而是将它...