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How to select rows with one or more nulls from a pandas DataFrame without listing columns explicitly
I have a dataframe with ~300K rows and ~40 columns.
I want to find out if any rows contain null values - and put these 'null'-rows into a separate dataframe so that I could explore them easily.
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Creating a expressjs middleware that accepts parameters
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function HasRole(role) {
return function(req, res, next) {
if (role !== req.user.role) res.redirect(...);
else next();
}
}
I also want to make sure that I don't make multiple copies of the same function:
function HasRole(role) {
return HasRole[role] || (HasRole[role] = fun...
Pass An Instantiated System.Type as a Type Parameter for a Generic Class
The title is kind of obscure. What I want to know is if this is possible:
6 Answers
6
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android get all contacts
...tsContract.Contacts.CONTENT_URI,
null, null, null, null);
if ((cur != null ? cur.getCount() : 0) > 0) {
while (cur != null && cur.moveToNext()) {
String id = cur.getString(
cur.getColumnIndex(ContactsContract.Contacts._ID));
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In PHP, how do you change the key of an array element?
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if the key value is not changing you will delete an array element. You might want to check for it.
– Peeech
Mar 10 '13 at 12:19
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Specifying and saving a figure with exact size in pixels
...nts of the figure to disk, resulting in an image of the exact size I specify in pixels.
6 Answers
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Join strings with a delimiter only if strings are not null or empty
This feels like it should be simple, so sorry if I'm missing something here, but I'm trying to find a simple way to concatenate only non-null or non-empty strings.
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How can I extract all values from a dictionary in Python?
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If you only need the dictionary keys 1, 2, and 3 use: your_dict.keys().
If you only need the dictionary values -0.3246, -0.9185, and -3985 use: your_dict.values().
If you want both keys and values use: your_dict.items() whi...
Getting a map() to return a list in Python 3.x
...t cases, this ends up saving memory, and should make things go faster.
If all you're going to do is iterate over this list eventually, there's no need to even convert it to a list, because you can still iterate over the map object like so:
# Prints "ABCD"
for ch in map(chr,[65,66,67,68]):
p...
OO Design in Rails: Where to put stuff
...e huge ActiveRecord subclasses and huge controllers is quite natural (even if you do use a controller per resource). If you were to create deeper object worlds, where would you put the classes (and modules, I suppose)? I'm asking about views (in the Helpers themselves?), controllers and models.
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