大约有 23,000 项符合查询结果（耗时：0.0544秒） [XML]
How to check if a column exists in Pandas
...ments, you can use the get() method for DataFrames. For performing the sum based on the question:
df['sum'] = df.get('A', df['B']) + df['C']
The DataFrame get method has similar behavior as python dictionaries.
share
...
Relative URL to a different port number in a hyperlink?
... For instance this modified code just worked for me and moves me from any base port to port 8069 (replace your port as required)
<div>
<a href="http://<?php print
$_SERVER{'SERVER_NAME'}; ?>:8069"><img
src="images/example.png"/>Example Base (http)</a>
<...
Difference between rake db:migrate db:reset and db:schema:load
... runs (single) migrations that have not run yet.
db:create creates the database
db:drop deletes the database
db:schema:load creates tables and columns within the (existing) database following schema.rb
db:setup does db:create, db:schema:load, db:seed
db:reset does db:drop, db:setup
db:migrate:reset ...
Haskell: Converting Int to String
...
An example based on Chuck's answer:
myIntToStr :: Int -> String
myIntToStr x
| x < 3 = show x ++ " is less than three"
| otherwise = "normal"
Note that without the show the third line will not compile.
...
Convert RGBA PNG to RGB with PIL
...e's a version that's much simpler - not sure how performant it is. Heavily based on some django snippet I found while building RGBA -> JPG + BG support for sorl thumbnails.
from PIL import Image
png = Image.open(object.logo.path)
png.load() # required for png.split()
background = Image.new("R...
Get all elements but the first from an array
...ySegment<> implements IList<>, IReadOnlyList<> and their base interfaces (including IEnumerable<>), so you can for example pass an ArraySegment<> to string.Join.
– Jeppe Stig Nielsen
Jan 25 '17 at 8:49
...
Is there a concurrent List in Java's JDK?
...
If you don't care about having index-based access and just want the insertion-order-preserving characteristics of a List, you could consider a java.util.concurrent.ConcurrentLinkedQueue. Since it implements Iterable, once you've finished adding all the items, yo...
Is there a combination of “LIKE” and “IN” in SQL?
In SQL I (sadly) often have to use " LIKE " conditions due to databases that violate nearly every rule of normalization. I can't change that right now. But that's irrelevant to the question.
...
How can you get the Manifest Version number from the App's (Layout) XML variables?
...
Oops. I must have been thinking Preference XML based on another comment.
– seastland
Nov 24 '13 at 18:44
...
What is the point of a “Build Server”? [closed]
... else wondering what the hell went wrong. (This was problematic in my Java-based job until I set up Hudson and we moved QA builds to that)
– MattC
Aug 24 '09 at 0:50
1
...