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Modifying a subset of rows in a pandas dataframe
...The df.A==0 expression creates a boolean series that indexes the rows, 'B' selects the column. You can also use this to transform a subset of a column, e.g.:
df.loc[df.A==0, 'B'] = df.loc[df.A==0, 'B'] / 2
I don't know enough about pandas internals to know exactly why that works, but the basic is...
Sublime Text 2: Trim trailing white space on demand
...way that uses no plugins or settings and works in most situations.
Multi-Select and move cursor to the end of every line
Hold CTRL-Shift, Press Left, Right
The spaces and tabs at the end of the lines should now be selected. Press Delete or Backspace
Note - Special characters such as ( and + may ...
Database Diagram Support Objects cannot be Installed … no valid owner
...rator and this has also invalidated the current owner of the database.
If SELECT @@SERVERNAME; is not accurate (it should say DevPC), then in order to ensure that your server rename has taken hold within SQL Server, you may also want to issue the following:
EXEC sp_dropserver @server = N'old serve...
Using “like” wildcard in prepared statement
...place("[", "![");
PreparedStatement pstmt = con.prepareStatement(
"SELECT * FROM analysis WHERE notes LIKE ? ESCAPE '!'");
pstmt.setString(1, notes + "%");
or a suffix-match:
pstmt.setString(1, "%" + notes);
or a global match:
pstmt.setString(1, "%" + notes + "%");
...
ORACLE 常用日期函数 - 数据库(内核) - 清泛网 - 专注C/C++及内核技术
...的日期。如果给出一负数，返回值日期之前几个月日期。select add_months(to_date(&...ADD_MONTHS函数在输入日期上加上指定的几个月返回一个新的日期。如果给出一负数，返回值日期之前几个月日期。
select add_months(to_date('20150201','yyyymmd...
Making macOS Installer Packages which are Developer ID ready
...gbuild
persisting obsolescence
Known Issues and Workarounds
Destination Select Pane
The user is presented with the destination select option with only a single choice - "Install for all users of this computer". The option appears visually selected, but the user needs to click on it in order to p...
Python in Xcode 4+?
...
In the menu bar, click “File” → “New” → “New Project…”.
Select “Other” in the left pane, then "External Build System" in the right page, and next click "Next".
Enter the product name, organization name, or organization identifier.
For the “Build Tool” field, type in /usr/l...
How to create id with AUTO_INCREMENT on Oracle?
...LACE TRIGGER dept_bir
BEFORE INSERT ON departments
FOR EACH ROW
BEGIN
SELECT dept_seq.NEXTVAL
INTO :new.id
FROM dual;
END;
/
UPDATE:
IDENTITY column is now available on Oracle 12c:
create table t1 (
c1 NUMBER GENERATED by default on null as IDENTITY,
c2 VARCHAR2(10)
);
...
Sqlite: CURRENT_TIMESTAMP is in GMT, not the timezone of the machine
...a unix
timestamp 1092941466, and compensate
for your local timezone.
SELECT datetime(1092941466, 'unixepoch', 'localtime');
That didn't look like it fit my needs, so I tried changing the "datetime" function around a bit, and wound up with this:
select datetime(timestamp, 'localtime')
That...
Fetch frame count with ffmpeg
.... See Edit lists below.
ffprobe: Query the container
ffprobe -v error -select_streams v:0 -show_entries stream=nb_frames -of default=nokey=1:noprint_wrappers=1 input.mp4
This is a fast method.
Not all formats (such as Matroska) will report the number of frames resulting in the output of N/A. ...