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Replacing Pandas or Numpy Nan with a None to use with MysqlDB
...s:
df1 = df.where(pd.notnull(df), None)
Note: this changes the dtype of all columns to object.
Example:
In [1]: df = pd.DataFrame([1, np.nan])
In [2]: df
Out[2]:
0
0 1
1 NaN
In [3]: df1 = df.where(pd.notnull(df), None)
In [4]: df1
Out[4]:
0
0 1
1 None
Note: what you ca...
SQL - many-to-many table primary key
...at the table sorted, just the index. And the index won't be stored sequentially, it'll be stored in an efficient manner to be able to be retrieved quickly.
In addition, the vast majority of database tables are read far more often than written. That makes anything you do on the select side far more ...
Linq style “For Each” [duplicate]
...
Calling ToList followed by ForEach involves iterating through the original collection twice. I'd prefer a standard foreach loop any day: less typing, more readable and better performance: foreach (var x in someValues) list.Add...
How do I change the number of open files limit in Linux? [closed]
...e using Linux and you got the permission error, you will need to raise the allowed limit in the /etc/limits.conf or /etc/security/limits.conf file (where the file is located depends on your specific Linux distribution).
For example to allow anyone on the machine to raise their number of open files...
What are Java command line options to set to allow JVM to be remotely debugged?
...ave this article bookmarked on setting this up for Java 5 and below.
Basically run it with:
-Xdebug -Xrunjdwp:transport=dt_socket,server=y,suspend=n,address=1044
For Java 5 and above, run it with:
-agentlib:jdwp=transport=dt_socket,server=y,suspend=y,address=1044
...
Getting rid of \n when using .readlines() [duplicate]
...string:
for i in contents:
alist.append(i.rstrip('\n'))
This leaves all other whitespace intact. If you don't care about whitespace at the start and end of your lines, then the big heavy hammer is called .strip().
However, since you are reading from a file and are pulling everything into mem...
Parse v. TryParse
...l indicating whether it succeeded.
TryParse does not just try/catch internally - the whole point of it is that it is implemented without exceptions so that it is fast. In fact the way it is most likely implemented is that internally the Parse method will call TryParse and then throw an exception if...
Jquery live() vs delegate() [duplicate]
...);
This, however, seems to me to be much more explicit about what is actually happening. You don't realise from the live example that the events are actually being captured on document; with delegate, it is clear that the event capturing happens on #containerElement. You can do the same thing wi...
How to require a fork with composer
...he most common (and easier) way of doing it is using a VCS repository.
All you have to do is add your fork as a repository and update the
version constraint to point to your custom branch. Your custom branch
name must be prefixed with dev-.
Example assuming you patched monolog to fix a bug...
How to get the first five character of a String
...e is wrong here. Consider a string with 10 blanks - your code will return all 10. Use IsNullOrEmpty instead. (It isn't good to combine IsNullOrWhiteSpace with any other test; Instead test for null+empty, then Trim if that is specified behavior, then do whatever tests/operations are needed.)
...