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Truncating all tables in a Postgres database
I regularly need to delete all the data from my PostgreSQL database before a rebuild. How would I do this directly in SQL?
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warning about too many open figures
...the other axes untouched.
plt.clf() clears the entire current figure with all its axes, but leaves the window opened, such that it may be reused for other plots.
plt.close() closes a window, which will be the current window, if not specified otherwise. plt.close('all') will close all open figures....
How to get current CPU and RAM usage in Python?
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Worked for me on OSX: $ pip install psutil; >>> import psutil; psutil.cpu_percent() and >>> psutil.virtual_memory() which returns a nice vmem object: vmem(total=8589934592L, available=4073336832L, percent=52.6, used=5022085120L, free=35602...
In which case do you use the JPA @JoinTable annotation?
... project_id
name name task_id
The Project_Tasks table is called a "Join Table". To implement this second solution in JPA you need to use the @JoinTable annotation. For example, in order to implement a uni-directional one-to-many association, we can define our entities as such:
Proj...
How do I base64 encode (decode) in C?
... *output_length = 4 * ((input_length + 2) / 3);
char *encoded_data = malloc(*output_length);
if (encoded_data == NULL) return NULL;
for (int i = 0, j = 0; i < input_length;) {
uint32_t octet_a = i < input_length ? (unsigned char)data[i++] : 0;
uint32_t octet_b = ...
How do I convert between big-endian and little-endian values in C++?
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If you're using Visual C++ do the following: You include intrin.h and call the following functions:
For 16 bit numbers:
unsigned short _byteswap_ushort(unsigned short value);
For 32 bit numbers:
unsigned long _byteswap_ulong(unsigned long value);
For 64 bit numbers:
unsigned __int64 _byt...
Delete all but the most recent X files in bash
...n a pretty standard UNIX environment with bash, to run a command to delete all but the most recent X files from a directory?
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How to force link from iframe to be opened in the parent window
...of the page in the iframe:
<base target="_parent">
This will load all links on the page in the parent window. If you want your links to load in a new window, use:
<base target="_blank">
This tag is fully supported in all browsers.
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Can I use __init__.py to define global variables?
I want to define a constant that should be available in all of the submodules of a package. I've thought that the best place would be in in the __init__.py file of the root package. But I don't know how to do this. Suppose I have a few subpackages and each with several modules. How can I access th...
How to convert JSON data into a Python object
...ry, the order of items will directly correspond.". Good to know for such small, local code blocks. I'd add a comment though to explicitly alert maintainers of code of such a dependency.
– cfi
Jun 1 '16 at 7:33
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