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Pandas - Get first row value of a given column
...ase the assignment succeeds in modifying df:
In [22]: df = pd.DataFrame({'foo':list('ABC')}, index=[0,2,1])
In [24]: df['bar'] = 100
In [25]: df['bar'].iloc[0] = 99
/home/unutbu/data/binky/bin/ipython:1: SettingWithCopyWarning:
A value is trying to be set on a copy of a slice from a DataFrame
See...
Get a list of all git commits, including the 'lost' ones
...of a branch, it's rather like finding a needle in a haystack. You can find all the commits that don't appear to be referenced any more- git fsck --unreachable will do this for you- but that will include commits that you threw away after a git commit --amend, old commits on branches that you rebased ...
CoffeeScript, When to use fat arrow (=>) over arrow (->) and vice versa
When building a class in CoffeeScript, should all the instance method be defined using the => ("fat arrow") operator and all the static methods being defined using the -> operator?
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What is the strict aliasing rule?
...n(void)
{
// Get a 32-bit buffer from the system
uint32_t* buff = malloc(sizeof(Msg));
// Alias that buffer through message
Msg* msg = (Msg*)(buff);
// Send a bunch of messages
for (int i = 0; i < 10; ++i)
{
msg->a = i;
msg->b = i+1;...
Why do I get AttributeError: 'NoneType' object has no attribute 'something'?
...one and you're attempting to access an attribute of it called 'something'.
foo = None
foo.something = 1
or
foo = None
print(foo.something)
Both will yield an AttributeError: 'NoneType'
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How to print time in format: 2009‐08‐10 18:17:54.811
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Superb answer. I could do all sorts of things in PHP, but knew it was all there already in C. THanks.
– Vijay Kumar Kanta
Jan 23 '14 at 12:43
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Python function global variables?
...hem, is the following a valid way to go about using them? (I am trying to call the global copy of a variable created in a separate function.)
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What is getattr() exactly and how do I use it?
... understand about getattr() is that getattr(li, "pop") is the same as calling li.pop .
14 Answers
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How to pass command line arguments to a rake task
...ays:
namespace :thing do
desc "it does a thing"
task :work, [:option, :foo, :bar] do |task, args|
puts "work", args
end
task :another, [:option, :foo, :bar] do |task, args|
puts "another #{args}"
Rake::Task["thing:work"].invoke(args[:option], args[:foo], args[:bar])
# or s...
What does mysql error 1025 (HY000): Error on rename of './foo' (errorno: 150) mean?
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You usually get this error if your tables use the InnoDB engine. In that case you would have to drop the foreign key, and then do the alter table and drop the column.
But the tricky part is that you can't drop the foreign key using...