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adding noise to a signal in python
...et SNR
# Set a target SNR
target_snr_db = 20
# Calculate signal power and convert to dB
sig_avg_watts = np.mean(x_watts)
sig_avg_db = 10 * np.log10(sig_avg_watts)
# Calculate noise according to [2] then convert to watts
noise_avg_db = sig_avg_db - target_snr_db
noise_avg_watts = 10 ** (noise_avg_d...
Append values to a set in Python
...
The way I like to do this is to convert both the original set and the values I'd like to add into lists, add them, and then convert them back into a set, like this:
setMenu = {"Eggs", "Bacon"}
print(setMenu)
> {'Bacon', 'Eggs'}
setMenu = set(list(setMen...
Select last row in MySQL
How can I SELECT the last row in a MySQL table?
10 Answers
10
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What are the differences between poll and select?
I am referring to the POSIX standard select and poll system C API calls.
3 Answers
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postgresql: INSERT INTO … (SELECT * …)
...ostgres
CREATE TABLE tblA (id serial, time integer);
INSERT INTO tblA
SELECT id, time
FROM dblink('dbname=dbtest', 'SELECT id, time FROM tblB')
AS t(id integer, time integer)
WHERE time > 1000;
TABLE tblA;
id | time
----+------
1 | 5000
2 | 2000
(2 rows)
PostgreSQL has ...
How to read/write a boolean when implementing the Parcelable interface?
...ionRight = (in.readInt() == 0) ? false : true;
boolean type needs to be converted to something that Parcel supports and so we can convert it to int.
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Coding Practices which enable the compiler/optimizer to make a faster program
...Arithmetic (Edited: applied code format to code fragment, added example)
Convert if statements into boolean assignments. Some processors can conditionally execute instructions without branching:
bool status = true;
status = status && /* first test */;
status = status && /* second...
Search All Fields In All Tables For A Specific Value (Oracle)
...based on
what I think it should be named but it
returned no results.*
SELECT * from dba_objects WHERE
object_name like '%DTN%'
A column isn't an object. If you mean that you expect the column name to be like '%DTN%', the query you want is:
SELECT owner, table_name, column_name FROM all_tab...
how to exclude null values in array_agg like in string_agg using postgres?
...
SQL Fiddle
select
id,
(select array_agg(a) from unnest(canonical_users) a where a is not null) canonical_users,
(select array_agg(a) from unnest(non_canonical_users) a where a is not null) non_canonical_users
from (
SELE...
How to remove all leading zeroes in a string
... @NabeelKhan That would not answer the question, which does not ask to convert the string to an integer. See the comments on Svisstack's answer for why this is not such a great solution.
– lonesomeday
Apr 18 '16 at 8:15
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