大约有 46,000 项符合查询结果（耗时：0.0457秒） [XML]
Counting the number of elements with the values of x in a vector
... 2 2 1 1 2 1 2 1 3 1 1 1 1
Then you can subset it:
> a[names(a)==435]
435
3
Or convert it into a data.frame if you're more comfortable working with that:
> as.data.frame(table(numbers))
numbers Freq
1 4 2
2 5 1
3 23 2
4 3...
Groovy: what's the purpose of “def” in “def x = 0”?
...taken from the Groovy Semantics Manual page ), why prefix the assignment with the keyword def ?
6 Answers
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iPhone Keyboard Covers UITextField
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The usual solution is to slide the field (and everything above it) up with an animation, and then back down when you are done. You may need to put the text field and some of the other items into another view and slide the view as a unit. (I call these things "plates" as in "tectonic pl...
Unable to execute dex: method ID not in [0, 0xffff]: 65536
...or Android adds support for multi-dex. To enable, you just have to declare it in build.gradle:
android {
defaultConfig {
...
multiDexEnabled true
}
}
If your application supports Android prior to 5.0 (that is, if your minSdkVersion is 20 or below) you also have to dynamically p...
Java: Static Class?
I have a class full of utility functions. Instantiating an instance of it makes no semantic sense, but I still want to call its methods. What is the best way to deal with this? Static class? Abstract?
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GitHub: Permission denied (publickey). fatal: The remote end hung up unexpectedly
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If you clone to a directory where you have user permission ( /home/user/git) it will work fine.
(Explanation: Running a command as superuser will not work with the same public key as running a command as user. Therefore Github refused the connection.)
This solution requires a SSH key already to...
What is the easiest way to remove all packages installed by pip?
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I've found this snippet as an alternative solution. It's a more graceful removal of libraries than remaking the virtualenv:
pip freeze | xargs pip uninstall -y
In case you have packages installed via VCS, you need to exclude those lines and remove the packages manually (e...
JavaScript, elegant way to check nested object properties for null/undefined [duplicate]
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You can use an utility function like this:
get = function(obj, key) {
return key.split(".").reduce(function(o, x) {
return (typeof o == "undefined" || o === null) ? o : o[x];
}, obj);
}
Usage:
get(user, 'loc.lat') // 50...
Using an ORM or plain SQL? [closed]
...e of the apps I've developed (then proceeded to forget about), I've been writing plain SQL, primarily for MySQL. Though I have used ORMs in python like SQLAlchemy , I didn't stick with them for long. Usually it was either the documentation or complexity (from my point of view) holding me back.
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What's a Good Javascript Time Picker? [closed]
...dalone js? I would like something like google uses in their calendar where it has a drop down of common times in 15min intervals or lets you manually type in a time and it validates it.
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