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How to exit an if clause
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102
(This method works for ifs, multiple nested loops and other constructs that you can't break fr...
Does the C++ standard mandate poor performance for iostreams, or am I just dealing with a poor imple
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edited Dec 3 '10 at 2:36
answered Dec 2 '10 at 23:40
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Quickest way to convert a base 10 number to any base in .NET?
...ts binary representation
Console.WriteLine(binary); // prints 101
However, as pointed out by the comments, Convert.ToString only supports the following limited - but typically sufficient - set of bases: 2, 8, 10, or 16.
Update (to meet the requirement to convert to any base):
I'm n...
Calculating width from percent to pixel then minus by pixel in LESS CSS
...ill calculate width in some element from percent to pixel so I will minus -10px via using LESS and calc() . It´s possible?
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Random row selection in Pandas dataframe
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answered Apr 10 '13 at 10:55
eumiroeumiro
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super() in Java
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answered Sep 22 '10 at 8:09
pakorepakore
10.5k1010 gold badges3939 silver badges6262 bronze badges
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Add zero-padding to a string
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answered Jun 26 '10 at 4:18
kemiller2002kemiller2002
105k2525 gold badges186186 silver badges242242 bronze badges
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More than 10 lines in a node.js stack error?
Is there a way to get more than 10 lines in a node.js stack error?
4 Answers
4
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Remove duplicated rows using dplyr
...ow:
library(dplyr)
set.seed(123)
df <- data.frame(
x = sample(0:1, 10, replace = T),
y = sample(0:1, 10, replace = T),
z = 1:10
)
One approach would be to group, and then only keep the first row:
df %>% group_by(x, y) %>% filter(row_number(z) == 1)
## Source: local data frame [...
IN vs OR in the SQL WHERE Clause
...h your specific data to see which is faster.
I tried both on a MySQL with 1000000 rows. When the column is indexed there is no discernable difference in performance - both are nearly instant. When the column is not indexed I got these results:
SELECT COUNT(*) FROM t_inner WHERE val IN (1000, 2000,...