For problems where it seems to be an error on a line you think is correct, you can often remove/comment the line where the error appears to be and, if the error moves to the next line, there are two possibilities. Either both lines have a problem or the previous line has a problem which is being carried forward. … Read more
Xpenology isn’t a linux OS like Ubuntu or other common distribution. It’s a bootloader for synologys operating system DSM, which they use on their NAS devices. DSM is running on a custom linux version developed by Synology, so it’s also not real compareable to desktop/server distributions in a direct way. Its optimized for running on … Read more
UNION removes duplicate records (where all columns in the results are the same), UNION ALL does not. There is a performance hit when using UNION instead of UNION ALL, since the database server must do additional work to remove the duplicate rows, but usually you do not want the duplicates (especially when developing reports). UNION Example: Result: UNION ALL example: Result:
SQL Server databases use two files – an MDF file, known as the primary database file, which contains the schema and data, and a LDF file, which contains the logs. See wikipedia. A database may also use secondary database file, which normally uses a .ndf extension. As John S. indicates, these file extensions are purely convention … Read more
There are several differences between HashMap and Hashtable in Java: Hashtable is synchronized, whereas HashMap is not. This makes HashMap better for non-threaded applications, as unsynchronized Objects typically perform better than synchronized ones. Hashtable does not allow null keys or values. HashMap allows one null key and any number of null values. One of HashMap’s subclasses is LinkedHashMap, so in the event that you’d want predictable iteration order (which is insertion order by default), you … Read more
First make sure you have checked the most voted answer. I’m not sure if it’s exactly your problem, but in my case, I wasn’t able to upgrade Django to 1.2.4 – I was always finishing with 1.2.3 version, so I uninstalled Django with: Then I removed <virtualenv>/build/Django directory and finally I installed the proper version with:
Really the ideal way to do this is to not use pull at all, but instead fetch and reset: (Altering master to whatever branch you want to be following.) pull is designed around merging changes together in some way, whereas reset is designed around simply making your local copy match a specific commit. You may want to consider slightly different options to clean depending on your system’s … Read more
Primarily for older phones I only encountered the App not installed error when trying to install an apk on my phone which runs on 4.4.2 aka KitKat, but my friend did not encounter this error on his phone which runs on 6+. I tried the other solutions such as removing the old/debug version of the app because … Read more
The SettingWithCopyWarning was created to flag potentially confusing “chained” assignments, such as the following, which does not always work as expected, particularly when the first selection returns a copy. [see GH5390 and GH5597 for background discussion.] The warning offers a suggestion to rewrite as follows: However, this doesn’t fit your usage, which is equivalent to: While it’s clear that you don’t care … Read more
Your problem is that you installed two different Pythons, a 32-bit 3.6, and a 64-bit 3.6. The first pip on your PATH is the one for the 32-bit 3.6. So, when you pip install numpy, it’s downloading the 32-bit NumPy, and installing into the site-packages for the 32-bit Python. But your py launcher is defaulting to running the 64-bit 3.6, … Read more