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Convert a row of a data frame to vector
...u have to be careful if your row contains a factor. Here is an example:
df_1 = data.frame(V1 = factor(11:15),
V2 = 21:25)
df_1[1,] %>% as.numeric() # you expect 11 21 but it returns
[1] 1 21
Here is another example (by default data.frame() converts characters to factors)
d...
Can you find all classes in a package using reflection?
...0, file.getName().length() - 6)));
}
}
return classes;
}
__________
1 This method was taken originally from http://snippets.dzone.com/posts/show/4831, which was archived by the Internet Archive, as linked to now. The snippet is also available at https://dzone.com/articles/get-all-c...
How to get last items of a list in Python?
...
a negative index will count from the end of the list, so:
num_list[-9:]
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What is an intuitive explanation of the Expectation Maximization technique? [closed]
...n.
This is the estimate of the variance, take the positive square
root to find the standard deviation.
"""
variance = np.sum(weight * (data - mean)**2) / np.sum(weight)
return np.sqrt(variance)
# new estimates for standard deviation
blue_std_guess = estimate_std(both_colours, b...
How can I check if a string represents an int, without using try/except?
...0' format, which is similar to int casting in this sense.
edit:
def check_int(s):
if s[0] in ('-', '+'):
return s[1:].isdigit()
return s.isdigit()
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Virtual Memory Usage from Java under Linux, too much memory used
...6-x64/jre/lib/amd64/libjava.so
...
00007fa1f34aa000 1576K r-x-- /lib/x86_64-linux-gnu/libc-2.13.so
00007fa1f3634000 2044K ----- /lib/x86_64-linux-gnu/libc-2.13.so
00007fa1f3833000 16K r-x-- /lib/x86_64-linux-gnu/libc-2.13.so
00007fa1f3837000 4K rwx-- /lib/x86_64-linux-gnu/libc-2.13....
How to convert a string to utf-8 in Python
...
In Python 2
>>> plain_string = "Hi!"
>>> unicode_string = u"Hi!"
>>> type(plain_string), type(unicode_string)
(<type 'str'>, <type 'unicode'>)
^ This is the difference between a byte string (plain_string) and a unic...
Quickest way to convert a base 10 number to any base in .NET?
... digits = (new[] { NullDigit }).Concat(digits);
}
_digitToIndexMap =
digits
.Select((digit, index) => new { digit, index })
.ToDictionary(keySelector: x => x.digit, elementSelector: x => x.index);
_radix =...
What are dictionary view objects?
...
>>> del dishes['eggs']
>>> keys # No eggs anymore!
dict_keys(['sausage', 'bacon', 'spam'])
>>> values # No eggs value (2) anymore!
dict_values([1, 1, 500])
(The Python 2 equivalent uses dishes.viewkeys() and dishes.viewvalues().)
This example shows the dynamic char...
How to call C from Swift?
... frame = CGRect(x: 10, y: 10, width: 100, height: 100)
import Darwin
for _ in 1..10 {
println(rand() % 100)
}
See Interacting with Objective-C APIs in the docs.
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