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How can I shrink the drawable on a button?
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16 Answers
16
Active
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dplyr summarise: Equivalent of “.drop=FALSE” to keep groups with zero length in output
...e .drop argument that does just what you asked for:
df = data.frame(a=rep(1:3,4), b=rep(1:2,6))
df$b = factor(df$b, levels=1:3)
df %>%
group_by(b, .drop=FALSE) %>%
summarise(count_a=length(a))
#> # A tibble: 3 x 2
#> b count_a
#> <fct> <int>
#> 1 1 ...
Split string with delimiters in C
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165
You can use the strtok() function to split a string (and specify the delimiter to use). Note t...
Accessing the index in 'for' loops?
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edited Sep 17 '16 at 10:13
Peter Mortensen
26.5k2121 gold badges9292 silver badges122122 bronze badges
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Representing and solving a maze given an image
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10 Answers
10
Active
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Check if all elements in a list are identical
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General method:
def checkEqual1(iterator):
iterator = iter(iterator)
try:
first = next(iterator)
except StopIteration:
return True
return all(first == rest for rest in iterator)
One-liner:
def checkEqual2(iterator):
r...
How to smooth a curve in the right way?
...ort numpy as np
import matplotlib.pyplot as plt
x = np.linspace(0,2*np.pi,100)
y = np.sin(x) + np.random.random(100) * 0.2
yhat = savitzky_golay(y, 51, 3) # window size 51, polynomial order 3
plt.plot(x,y)
plt.plot(x,yhat, color='red')
plt.show()
UPDATE: It has come to my attention that the co...
SQL query return data from multiple tables
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Part 1 - Joins and Unions
This answer covers:
Part 1
Joining two or more tables using an inner join (See the wikipedia entry for additional info)
How to use a union query
Left and Right Outer Joins (this stackOverflow answer ...
Creating a zero-filled pandas data frame
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140
You can try this:
d = pd.DataFrame(0, index=np.arange(len(data)), columns=feature_list)
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Numpy: Get random set of rows from 2D array
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>>> A = np.random.randint(5, size=(10,3))
>>> A
array([[1, 3, 0],
[3, 2, 0],
[0, 2, 1],
[1, 1, 4],
[3, 2, 2],
[0, 1, 0],
[1, 3, 1],
[0, 4, 1],
[2, 4, 2],
[3, 3, 1]])
>>> idx = np....