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How do I count the number of occurrences of a char in a String?
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The loop method is much faster than this. Especially when wanting to count a char instead of a String (since there is no String.replace(char, char) method). On a 15 character string, I get a difference of 6049 ns vs 26,739 ns (averaged over 100runs). Raw numbers are huge...
Change a Django form field to a hidden field
...get the value.
also you may prefer to use in the view:
form.fields['field_name'].widget = forms.HiddenInput()
but I'm not sure it will protect save method on post.
Hope it helps.
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Using OR in SQLAlchemy
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From the tutorial:
from sqlalchemy import or_
filter(or_(User.name == 'ed', User.name == 'wendy'))
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What does numpy.random.seed(0) do?
... I'm not very familiar with NumPy's random state generator stuff, so I'd really appreciate a layman's terms explanation of this.
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Converting datetime.date to UTC timestamp in Python
...le (e.g., via tzlocal.get_localzone()) to get access to the tz database on all platforms. Also, utcfromtimestamp() may fail and mktime() may return non-POSIX timestamp if "right" timezone is used.
To convert datetime.date object that represents date in UTC without calendar.timegm():
DAY = 24*60*...
How can I copy the output of a command directly into my clipboard?
... down the complete procedure just in case anyone else needs it.
First install a 16 kB program called xclip:
sudo apt-get install xclip
You can then pipe the output into xclip to be copied into the clipboard:
cat file | xclip
To paste the text you just copied, you shall use:
xclip -o
To si...
Determine what attributes were changed in Rails after_save callback?
I'm setting up an after_save callback in my model observer to send a notification only if the model's published attribute was changed from false to true. Since methods such as changed? are only useful before the model is saved, the way I'm currently (and unsuccessfully) trying to do so is as fol...
How to rename a single column in a data.frame?
...r.name'
This code pretty much does the following:
names(df) looks into all the names in the df
[names(df) == old.var.name] extracts the variable name you want to check
<- 'new.var.name' assigns the new variable name.
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How can you get the Manifest Version number from the App's (Layout) XML variables?
...ntext.getPackageName(), 0).versionName;
Either of these solutions would allow for placing the version name in XML. Unfortunately there isn't a nice simple solution, like android.R.string.version or something like that.
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Python: changing value in a tuple
...'m new to python so this question might be a little basic. I have a tuple called values which contains the following:
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