我遇到了opam和锁定文件的问题.
chris@chris:~$ opam upgrade
Another process (19525) has already locked "/home/chris/.opam/4.00.1/lock". Retrying in 1s (0/5)
Another process (19525) has already locked "/home/chris/.opam/4.00.1/lock". Retrying in 1s (1/5)
Another process (19525) has already locked "/home/chris/.opam/4.00.1/lock". Retrying in 1s (2/5)
Another process (19525) has already locked "/home/chris/.opam/4.00.1/lock". Retrying in 1s (3/5)
Another process (19525) has already locked "/home/chris/.opam/4.00.1/lock". Retrying in 1s (4/5)
'opam upgrade' failed.
# opam-version 1.1.0
# os linux
Too many attempts. Cancelling.
我不太确定问题是什么.我对整个系统缺乏经验.我不认为它与aspcud有任何关系,因为我没有安装它.我正在使用的机器正在运行Ubuntu 13.谢谢大家.
编辑:
我试图重新启动,这是当我尝试杀死进程时发生的事情
chris@chris:~/dev$ kill 19525
bash: …我想做一些相当简单的事情.我想取一个字符串,如"1000",并返回字符串"1000".
这是我的尝试:
String.map (function x -> if x = ',' then '' else x) "1,000";;
但是我收到一个编译错误,说有一个语法错误wrt ''
感谢您的见解!
我在尝试为Scala版本2.10.2安装.deb文件时遇到问题.
我收到以下错误:
(Reading database ...
(Reading database ... 5%
(Reading database ... 10%
(Reading database ... 15%
(Reading database ... 20%
(Reading database ... 25%
(Reading database ... 30%
(Reading database ... 35%
(Reading database ... 40%
(Reading database ... 45%
(Reading database ... 50%
(Reading database ... 55%
(Reading database ... 60%
(Reading database ... 65%
(Reading database ... 70%
(Reading database ... 75%
(Reading database ... 80%
(Reading database ... 85%
(Reading database ... 90%
(Reading database ... …我有一个Scala Play网络应用程序,它从数据库中提取html变量,然后将它们放在模板中.像这样的东西
<div>@myvar</div>
我的var是一个html字符串.在myvar没有被模板引擎为html recongized.所以我得到了这样的输出
<h3>MY HEADING</h3>
而不是由Scala播放模板引擎呈现的h3标签到正确的html H3标签.
我需要在哪里渲染这些变量？我试图在我的控制器中做到但显然已经失败了.
谢谢!
我在编写以下代码时遇到问题:
D = [
[0,3,8,999,-4],
[999,0,999,1,7],
[999,4,0,999,999],
[2,999,-5,0,999],
[999,999,999,6,0]
]
def FloydWarshall (W):
matrices = [W[:]]
pred = [W[:]]
print (matrices is pred)
print (pred is matrices)
print (pred is W)
print (matrices is W)
for i in range(0,len(pred[0])):
for j in range(len(pred[0][i])):
if pred[0][i][j] != 999 and pred[0][i][j] != 0:
pred[0][i][j] = i +1
else:
pred[0][i][j] = False
return (matrices,pred)
FloydWarshall(D)
返回的值是完全相同的矩阵,为什么会这样？print语句说它们不是指向内存中相同位置的指针,对吗？
在这里完成noob到haskell,我正在尝试使下面这段代码工作:
它的目的是获取列表的第一个exp元素,连接它们,然后再次调用相同的函数.
order ( i ) (l1)(l2) =
do exp <- (2 ^ i)
l <- (take exp l1) ++ (take exp l2 ) ++ (order (i+1) (drop exp l1) (drop exp l2));
return l
我敢肯定,这远非惯用的哈斯克尔,但你必须在某个地方开始.
我得到的错误是在
exp <- (2 ^ i )
这样说
No instance for (Num [Int])
arising from a use of `^'
Possible fix: add an instance declaration for (Num [Int])
我真的不确定这究竟意味着什么.是不是2和i都是整数,然后应用指数函数会产生整数？
谢谢!