大约有 47,000 项符合查询结果（耗时：0.0675秒） [XML]
Why does running the Flask dev server run itself twice?
...g is the library that supplies Flask with the development server when you call app.run().
See the restart_with_reloader() function code; your script is run again with subprocess.call().
If you set use_reloader to False you'll see the behaviour go away, but then you also lose the reloading function...
Inserting multiple rows in mysql
...
When loading a table from a text file, use LOAD DATA INFILE. This is usually 20 times faster than using INSERT statements.
Optimizing INSERT Statements
You can find more tips on how to speed up your insert statements on the link above.
...
javac error: Class names are only accepted if annotation processing is explicitly requested
...this in a file called Main.java:
public Main{
public static void main(String[] args){
System.out.println("ok");
}
}
Then compile it like this:
user@defiant /home/user $ javac Main
error: Class names, 'Main', are only accepted if
annotation processing is explicitly requested
1 er...
Progress indicator during pandas operations
...se you're interested in how this works (and how to modify it for your own callbacks), see the examples on github, the full documentation on pypi, or import the module and run help(tqdm). Other supported functions include map, applymap, aggregate, and transform.
EDIT
To directly answer the original ...
How to verify if a file exists in a batch file?
...
Reminder: IF, EXIST, ELSE, REM, DEL, etc. all work in lowercase as well!
– Terra Ashley
Jul 19 '16 at 23:57
1
...
Is there any difference between the `:key => “value”` and `key: “value”` hash notations?
...
Ruby hash-keys assigned by hash-rockets can facilitate strings for key-value pairs (e.g. 's' => x) whereas key assignment via symbols (e.g. key: "value" or :key => "value") cannot be assigned with strings. Although hash-rockets provide freedom and functionality for hash-ta...
How to filter None's out of List[Option]?
...the same time, you can use flatten:
scala> someList.flatten
res0: List[String] = List(Hello, Goodbye)
share
|
improve this answer
|
follow
|
...
Best way to iterate through a Perl array
...ay elements occurs. ($_ is aliased to the element in #1, but #2 and #3 actually copy the scalars from the array.)
#5 might be similar.
In terms memory usage: They're all the same except for #5.
for (@a) is special-cased to avoid flattening the array. The loop iterates over the indexes of the array...
What is the _snowman param in Ruby on Rails 3 forms for?
...net Explorer (5, 6, 7 and 8) to encode its parameters as unicode.
Specifically, this bug can be triggered if the user switches the browser's encoding to Latin-1. To understand why a user would decide to do something seemingly so crazy, check out this google search. Once the user has put the web-sit...
How do I generate random number for each row in a TSQL Select?
...change your range, just change the number at the end of the expression. Be extra careful if you need a range that includes both positive and negative numbers. If you do it wrong, it's possible to double-count the number 0.
A small warning for the math nuts in the room: there is a very slight bias i...