大约有 43,000 项符合查询结果（耗时：0.0507秒） [XML]
How to parse Excel (XLS) file in Javascript/HTML5
...with it. I need to read xls file row-wise, read data in every column and convert it to JSON.
11 Answers
...
List columns with indexes in PostgreSQL
... uk_test3c unique (c),constraint uk_test3ab unique (a, b));
List indexes and columns indexed:
select
t.relname as table_name,
i.relname as index_name,
a.attname as column_name
from
pg_class t,
pg_class i,
pg_index ix,
pg_attribute a
where
t.oid = ix.indrelid
an...
Random number generator only generating one random number
...
Every time you do new Random() it is initialized using the clock. This means that in a tight loop you get the same value lots of times. You should keep a single Random instance and keep using Next on the same instance.
//Function to get a random n...
Java Naming Convention with Acronyms [closed]
...
@DerFlatulator: it's a question of automation when converting from UpperCamelCase to lowerCamelCase: I had the problem when automating Hibernate mapping to a snake_case: DvdPlayer -> dvd_player but DVDPlayer -> d_v_d_player. There is no way to automate DVDPlayer to dvd_...
pandas GroupBy columns with NaN (missing) values
...cient topic, if someone still stumbles over this--another workaround is to convert via .astype(str) to string before grouping. That will conserve the NaN's.
df = pd.DataFrame({'a': ['1', '2', '3'], 'b': ['4', np.NaN, '6']})
df['b'] = df['b'].astype(str)
df.groupby(['b']).sum()
a
b
4 1
6 ...
Wrong requestCode in onActivityResult
... Just a note: if you use startActivityForResult in a fragment and expect the result from onActivityResult in that fragment, just make sure you call super.onActivityResult in the host activity (in case you override that method there). This is because the activity's onActivityResult seems...
What's the point of g++ -Wreorder?
...hat somebody might see the list of member initialisers in the constructor, and think that they're executed in that order (j first, then i). They are not, they are executed in the order the members are defined in the class.
Suppose you wrote A(): j(0), i(j) {}. Somebody might read that, and think th...
Confused about __str__ on list in Python [duplicate]
...
Python has two different ways to convert an object to a string: str() and repr(). Printing an object uses str(); printing a list containing an object uses str() for the list itself, but the implementation of list.__str__() calls repr() for the individual it...
Multidimensional Array [][] vs [,] [duplicate]
...
One is an array of arrays, and one is a 2d array. The former can be jagged, the latter is uniform.
That is, a double[][] can validly be:
double[][] x = new double[5][];
x[0] = new double[10];
x[1] = new double[5];
x[2] = new double[3];
x[3] = new d...
How to get the insert ID in JDBC?
...correct, Oracle JDBC driver is still somewhat troublesome with this. MySQL and DB2 already supported it for ages. PostgreSQL started to support it not long ago. I can't comment about MSSQL as I've never used it.
For Oracle, you can invoke a CallableStatement with a RETURNING clause or a SELECT CURR...