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How can I get the concatenation of two lists in Python without modifying either one? [duplicate]
In Python, the only way I can find to concatenate two lists is list.extend , which modifies the first list. Is there any concatenation function that returns its result without modifying its arguments?
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Difference between null and empty (“”) Java String
... @Zach L : when String s = null+"a"; it gives output nulla but null.concat("a") it gives the null pointer exception. what is the reason in my first case null+"a"; is working.
– Ved Prakash
Sep 14 '19 at 16:23
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Where in memory are my variables stored in C?
...---> heap also stack (the teacher was trying to trick you)
pointers(ex: char *arr, int *arr) -------> heap data or stack, depending on the context. C lets you declare a global or a static pointer, in which case the pointer itself would end up in the data segment.
dynamically allocated space(us...
C++ static virtual members?
...he interface for all the object types:
class Object
{
public:
virtual char* GetClassName() = 0;
};
Now we need an actual implementation. But to avoid having to write both the static and the virtual methods, we will have our actual object classes inherit the virtual methods. This does obviousl...
Generate fixed length Strings filled with whitespaces
I need to produce fixed length string to generate a character position based file. The missing characters must be filled with space character.
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OceanBase使用libeasy原理源码分析：服务器端 - 数据库(内核) - 清泛网 - ...
...EASY_OK,则signal信号量，从而工作线程被唤醒。
典型的，select请求这种需要回复多个包给MySQL客户端的场景使用的都是这种模式
其它诸如只需要回复一个包给MySQL客户端的DML操作，例如INSERT,UPDATE等也使用这种模式，只是工作线程...
What's the difference between __PRETTY_FUNCTION__, __FUNCTION__, __func__?
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__func__ is an implicitly declared identifier that expands to a character array variable containing the function name when it is used inside of a function. It was added to C in C99. From C99 §6.4.2.2/1:
The identifier __func__ is implicitly declared by the translator as if, immediatel...
Traverse all the Nodes of a JSON Object Tree with JavaScript
...ypeOf(value) === Object.prototype) {
traverse(value, callback, trail.concat(key))
} else {
callback.call(obj, key, value, trail)
}
})
}
traverse({a: {b: {c: {d: 1}}, e: {f: 2}}}, function (key, value, trail) {
console.log(arguments)
})
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How do I get a list of all the duplicate items using pandas in python?
...ds so many times. I prefer method #2: groupby on the ID.
>>> pd.concat(g for _, g in df.groupby("ID") if len(g) > 1)
ID ENROLLMENT_DATE TRAINER_MANAGING TRAINER_OPERATOR FIRST_VISIT_DATE
6 11795 3-Jul-12 0649597-White River VT 0649597-White River VT ...
Concatenating two lists - difference between '+=' and extend()
I've seen there are actually two (maybe more) ways to concatenate lists in Python:
One way is to use the extend() method:
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