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java中的缓存技术该如何实现 - 更多技术 - 清泛网 - 专注C/C++及内核技术
...慎.第四个环节,数据库中也可以有缓存, 比如说mysql的querycache.
那么也就是说在整个请求流程的任何一点,我们都可以加缓存.但是是所有的数据都可以放进缓存的吗.当然不是,需要放进缓存的数据总是有一些特征的,要清楚的判断...
Linear Regression and group by in R
I want to do a linear regression in R using the lm() function. My data is an annual time series with one field for year (22 years) and another for state (50 states). I want to fit a regression for each state so that at the end I have a vector of lm responses. I can imagine doing for loop for each ...
How can I delete a newline if it is the last character in a file?
...have some files that I'd like to delete the last newline if it is the last character in a file. od -c shows me that the command I run does write the file with a trailing new line:
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How to copy a dictionary and only edit the copy
Can someone please explain this to me? This doesn't make any sense to me.
20 Answers
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What is an unsigned char?
In C/C++, what an unsigned char is used for? How is it different from a regular char ?
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Is there a printf converter to print in binary format?
I can print with printf as a hex or octal number. Is there a format tag to print as binary, or arbitrary base?
52 Answer...
Why do you need explicitly have the “self” argument in a Python method?
When defining a method on a class in Python, it looks something like this:
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MongoDB/Mongoose querying at a specific date?
Is it possible to query for a specific date ?
6 Answers
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Capture iframe load complete event
Is there a way to capture when the contents of an iframe have fully loaded from the parent page?
6 Answers
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What is a plain English explanation of “Big O” notation?
I'd prefer as little formal definition as possible and simple mathematics.
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