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Objective-C: Where to remove observer for NSNotification?
.../no longer in a state in which they can properly handle the notification. For this... See above.
Edit (since the answer seems to draw more comments than I would have thought) All I am trying to say here is: it's really hard to give general advice as to when it's best to remove the observer from the...
Update a dataframe in pandas while iterating row by row
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You can assign values in the loop using df.set_value:
for i, row in df.iterrows():
ifor_val = something
if <condition>:
ifor_val = something_else
df.set_value(i,'ifor',ifor_val)
If you don't need the row values you could simply iterate over the indices...
What do the terms “CPU bound” and “I/O bound” mean?
... bound if it would go faster if the CPU were faster, i.e. it spends the majority of its time simply using the CPU (doing calculations). A program that computes new digits of π will typically be CPU-bound, it's just crunching numbers.
A program is I/O bound if it would go faster if the I/O subsyste...
Long list of if statements in Java
Sorry I can't find a question answering this, I'm almost certain someone else has raised it before.
15 Answers
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Can I delete a git commit but keep the changes?
In one of my development branches, I made some changes to my codebase. Before I was able to complete the features I was working on, I had to switch my current branch to master to demo some features. But just using a "git checkout master" preserved the changes I also made in my development branch, th...
how to concatenate two dictionaries to create a new one in Python? [duplicate]
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Slowest and doesn't work in Python3: concatenate the items and call dict on the resulting list:
$ python -mtimeit -s'd1={1:2,3:4}; d2={5:6,7:9}; d3={10:8,13:22}' \
'd4 = dict(d1.items() + d2.items() + d3.items())'
100000 loops, best of 3: 4.93 ...
How to find out if an item is present in a std::vector?
All I want to do is to check whether an element exists in the vector or not, so I can deal with each case.
18 Answers
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if a ngSrc path resolves to a 404, is there a way to fallback to a default?
The application I'm building requires my user to set 4 pieces of information before this image even has a chance of loading. This image is the center-piece of the application, so the broken image link makes it look like the whole thing is borked. I'd like to have another image take its place on a 4...
Java List.add() UnsupportedOperationException
... to add objects to a List<String> instance but it throws an UnsupportedOperationException .
Does anyone know why?
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How to compare two floating point numbers in Bash?
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More conveniently
This can be done more conveniently using Bash's numeric context:
if (( $(echo "$num1 > $num2" |bc -l) )); then
…
fi
Explanation
Piping through the basic calculator command bc returns either 1 or 0...