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Add column with constant value to pandas dataframe [duplicate]
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The reason this puts NaN into a column is because df.index and the Index of your right-hand-side object are different. @zach shows the proper way to assign a new column of zeros. In general, pandas tries to do as much alignment of indices as possible. One downside is that when indice...
Searching for UUIDs in text with regex
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@cyber-monk: [0-9a-f] is identical to [a-f0-9] and [0123456789abcdef] in meaning and in speed, since the regex is turned into a state machine anyway, with each hex digit turned into an entry in a state-table. For an entry point into how this works, see en.wikipedia.org/wi...
Obfuscated C Code Contest 2006. Please explain sykes2.c
...char(32 | (b & 1));
}
}
Now, note that a[b] is the same as b[a], and apply the -~ == 1+ change again:
main(int i) {
if(i != 448)
main(i+1);
i--;
if(i % 64 == 0) {
putchar('\n');
} else {
char a = (">'txiZ^(~z?"-48)[(__TIME__-i/8%8)[7]] + 1;
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How can I see the size of files and directories in linux? [closed]
How can I see the size of files and directories in Linux? If use df -m , then it shows the size of all the directory at the top level, but, for the directories and files inside the directory, how do I check the size?
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Fastest way to flatten / un-flatten nested JSON objects
I threw some code together to flatten and un-flatten complex/nested JSON objects. It works, but it's a bit slow (triggers the 'long script' warning).
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Pandas - Get first row value of a given column
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There is a difference between df_test['Btime'].iloc[0] (recommended) and df_test.iloc[0]['Btime']:
DataFrames store data in column-based blocks (where each block has a single
dtype). If you select by column first, a view can be returned (which is
quicker than returning a copy) and the origina...
What is the difference between shallow copy, deepcopy and normal assignment operation?
...wards the existing object. The docs explain the difference between shallow and deep copies:
The difference between shallow and deep copying is only relevant for
compound objects (objects that contain other objects, like lists or
class instances):
A shallow copy constructs a new compo...
Why do people say there is modulo bias when using a random number generator?
...it. So I am going to post one here which will hopefully help people understand why exactly there is "modulo bias" when using a random number generator, like rand() in C++.
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How do I use arrays in C++?
...sed virtually everywhere. C++ provides abstractions that are easier to use and less error-prone ( std::vector<T> since C++98 and std::array<T, n> since C++11 ), so the need for arrays does not arise quite as often as it does in C. However, when you read legacy code or interact with a...
How to hide first section header in UITableView (grouped style)
...the result is that drawings are no longer aligned to pixels, causing blurs and reducing performance. Just try it in the simulator: it has an option to highlight problematic alignment.
– Codo
Nov 1 '13 at 17:02
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