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How do I interpret precision and scale of a number in a database?
...
406
Numeric precision refers to the maximum number of digits that are present in the number.
ie ...
How to drop columns by name in a data frame
... function. For example :
R> df <- data.frame(x=1:5, y=2:6, z=3:7, u=4:8)
R> df
x y z u
1 1 2 3 4
2 2 3 4 5
3 3 4 5 6
4 4 5 6 7
5 5 6 7 8
Then you can use the which function and the - operator in column indexation :
R> df[ , -which(names(df) %in% c("z","u"))]
x y
1 1 2
2 2 3
3 3 4...
How to get a URL parameter in Express?
...ue on getting the value of tagid from my URL: localhost:8888/p?tagid=1234 .
4 Answers
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Appropriate datatype for holding percent values?
...ent (e.g. 100.00% stored as 1.0000), I would store the data in a decimal(5,4) data type with a CHECK constraint that ensures that the values never exceed 1.0000 (assuming that is the cap) and never go below 0 (assuming that is the floor). If you are going to store their face value (e.g. 100.00% is s...
Logical operators for boolean indexing in Pandas
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answered Jan 28 '14 at 20:22
unutbuunutbu
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Tell Ruby Program to Wait some amount of time
... construct longer intervals using the following convenience syntax:
sleep(4.minutes)
# or, even longer...
sleep(2.hours); sleep(3.days) # etc., etc.
# or shorter
sleep(0.5) # half a second
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How to group dataframe rows into list in pandas groupby?
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442
You can do this using groupby to group on the column of interest and then apply list to every ...
Split a vector into chunks in R
...(), split() and ceiling():
> d <- rpois(73,5)
> d
[1] 3 1 11 4 1 2 3 2 4 10 10 2 7 4 6 6 2 1 1 2 3 8 3 10 7 4
[27] 3 4 4 1 1 7 2 4 6 0 5 7 4 6 8 4 7 12 4 6 8 4 2 7 6 5
[53] 4 5 4 5 5 8 7 7 7 6 2 4 3 3 8 11 6 6 1 8 4
> m...
How do you grep a file and get the next 5 lines
How do I grep a file for 19:55 and get the Line 1,2,3,4,5?
3 Answers
3
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Pandas index column title or name
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394
You can just get/set the index via its name property
In [7]: df.index.name
Out[7]: 'Index Title...