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Nested attributes unpermitted parameters
... Person . I want a form that can create the Bill and its children Dues all in one page. I am trying to create a form using nested attributes, similar to ones in this Railscast .
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常用Sql - 数据库(内核) - 清泛网 - 专注C/C++及内核技术
... decimal(18,0) NOT NULL COMMENT '递增ID',
`FIELD_1` varchar(32) NOT NULL COMMENT '字段1',
`FIELD_2` varchar(32) NOT NULL COMMENT '字段2',
PRIMARY KEY (`ID`),
KEY `FIELD_1` (`FIELD_1`), #单索引
KE...
Preferred method to store PHP arrays (json_encode vs serialize)
...ciative array of data in a flat file for caching purposes. I might occasionally come across the need to convert it to JSON for use in my web app but the vast majority of the time I will be using the array directly in PHP.
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What is Node.js? [closed]
I don't fully get what Node.js is all about. Maybe it's because I am mainly a web based business application developer. What is it and what is the use of it?
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Read a zipped file as a pandas DataFrame
... you want to read a zipped or a tar.gz file into pandas dataframe, the read_csv methods includes this particular implementation.
df = pd.read_csv('filename.zip')
Or the long form:
df = pd.read_csv('filename.zip', compression='zip', header=0, sep=',', quotechar='"')
Description of the compr...
Multiple returns from a function
...
Technically, you can't return more than one value. However, there are multiple ways to work around that limitation. The way that acts most like returning multiple values, is with the list keyword:
function getXYZ()
{
return arr...
Find the files existing in one directory but not in the other [closed]
...rison is to use find with md5sum, then a diff.
Example:
Use find to list all the files in the directory then calculate the md5 hash for each file and pipe it to a file:
find /dir1/ -type f -exec md5sum {} \; > dir1.txt
Do the same procedure to the another directory:
find /dir2/ -type f -exe...
Can a C# lambda expression have more than one statement?
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(I'm assuming you're really talking about multiple statements rather than multiple lines.)
You can use multiple statements in a lambda expression using braces, but only the syntax which doesn't use braces can be converted into an expression tree:
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Python Pandas: Get index of rows which column matches certain value
... frame (whose data may be gibabytes). What about dftest? Doesn't this also allocate a very large intermediate object where the returned index may be very small, or even empty. Are these magically optimized away using lazy views. If not then surely there must be an efficient way.
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MySQL: Sort GROUP_CONCAT values
In short: Is there any way to sort the values in a GROUP_CONCAT statement?
2 Answers
2...