大约有 40,000 项符合查询结果（耗时：0.0642秒） [XML]
How can I efficiently download a large file using Go?
... Go that will store the content directly into a file instead of storing it all in memory before writing it to a file? Because the file is so big, storing it all in memory before writing it to a file is going to use up all the memory.
...
Using python map and other functional tools
...earn. A fundamental rule in functional programming is that every time you call a function with the same arguments, you ALWAYS get the same output. This avoids a vipers nest of bugs introduced by having global state. As maptest depends on an external definition of bars, this principle is broken.
...
Convert column classes in data.table
...hat is the idiomatic way of doing this for a subset of columns (instead of all of them)? I've defined a character vector convcols of columns. dt[,lapply(.SD,as.numeric),.SDcols=convcols] is almost instant while dt[,convcols:=lapply(.SD,as.numeric),.SDcols=convcols] almost freezes up R, so I'm guessi...
How to do a less than or equal to filter in Django queryset?
I am attempting to filter users by a custom field in each users profile called profile. This field is called level and is an integer between 0-3.
...
What is a 'Closure'?
... scope
When you declare a local variable, that variable has a scope. Generally, local variables exist only within the block or function in which you declare them.
function() {
var a = 1;
console.log(a); // works
}
console.log(a); // fails
If I try to access a local variable, most languag...
django admin - add custom form fields that are not part of the model
... ModelForm class and then declare your extra fields inside that as you normally would. I've also given an example of how you might use these values in form.save():
from django import forms
from yourapp.models import YourModel
class YourModelForm(forms.ModelForm):
extra_field = forms.CharFiel...
Batch script loop
...e
for /l %%x in (1, 1, 100) do echo %%x
(which is one of the things I really really hate about windows scripting)
If you have multiple commands for each iteration of the loop, do this:
for /l %x in (1, 1, 100) do (
echo %x
copy %x.txt z:\whatever\etc
)
or in a batch file
for /l %%x in ...
Why doesn't Dictionary have AddRange?
...doesn't have any meaning to an associative container, as the range of data allows for duplicate entries. E.g if you had an IEnumerable<KeyValuePair<K,T>> that collection does not guard against duplicate entries.
The behavior of adding a collection of key-value pairs, or even merging tw...
Simple insecure two-way data “obfuscation”?
...e to figure out your keys by just assuming that you used this code as-is! All you have to do is change some of the numbers (must be <= 255) in the Key and Vector arrays (I left one invalid value in the Vector array to make sure you do this...). You can use https://www.random.org/bytes/ to gener...
What is the scope of variables in JavaScript?
... even matter? Also, where are the variables stored if they are defined globally?
26 Answers
...