大约有 48,000 项符合查询结果（耗时：0.0377秒） [XML]
Benefits of using the conditional ?: (ternary) operator
What are the benefits and drawbacks of the ?: operator as opposed to the standard if-else statement. The obvious ones being:
...
What is the purpose of base 64 encoding and why it used in HTTP Basic Authentication?
...pedia page for HTTP Basic Authentication:
While encoding the user name and password with the Base64 algorithm typically makes them unreadable by the naked eye, they are as easily decoded as they are encoded. Security is not the intent of the encoding step. Rather, the intent of the encoding is t...
Apply a function to every row of a matrix or a data frame
Suppose I have a n by 2 matrix and a function that takes a 2-vector as one of its arguments. I would like to apply the function to each row of the matrix and get a n-vector. How to do this in R?
...
Check folder size in Bash
I'm trying to write a script that will calculate a directory size and if the size is less than 10GB, and greater then 2GB do some action. Where do I need to mention my folder name?
...
Fetch frame count with ffmpeg
...deo file using ffmpeg? The render output of ffmpeg shows the current frame and I need the frame count to calculate the progress in percent.
...
how to check the dtype of a column in python pandas
I need to use different functions to treat numeric columns and string columns. What I am doing now is really dumb:
6 Answer...
TypeError: got multiple values for argument
I read the other threads that had to do with this error and it seems that my problem has an interesting distinct difference than all the posts I read so far, namely, all the other posts so far have the error in regards to either a user created class or a builtin system resource. I am experiencing th...
Is there a Python function to determine which quarter of the year a date is in?
...ed to count from 1 instead;-).
Originally two answers, multiply upvoted and even originally accepted (both currently deleted), were buggy -- not doing the -1 before the division, and dividing by 4 instead of 3. Since .month goes 1 to 12, it's easy to check for yourself what formula is right:
fo...
How do I clone a Django model instance object and save it to the database?
...
Just change the primary key of your object and run save().
obj = Foo.objects.get(pk=<some_existing_pk>)
obj.pk = None
obj.save()
If you want auto-generated key, set the new key to None.
More on UPDATE/INSERT here.
Official docs on copying model instances: h...
What's the Hi/Lo algorithm?
...dea is that you have two numbers to make up a primary key- a "high" number and a "low" number. A client can basically increment the "high" sequence, knowing that it can then safely generate keys from the entire range of the previous "high" value with the variety of "low" values.
For instance, suppo...