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dplyr summarise: Equivalent of “.drop=FALSE” to keep groups with zero length in output
....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 ...
Pandas dataframe get first row of each group
...;> df.groupby('id').first()
value
id
1 first
2 first
3 first
4 second
5 first
6 first
7 fourth
If you need id as column:
>>> df.groupby('id').first().reset_index()
id value
0 1 first
1 2 first
2 3 first
3 4 second
4 5 first
5 6...
Bootstrap carousel multiple frames at once
This is the effect I'm trying to achieve with Bootstrap 3 carousel
14 Answers
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Python matplotlib multiple bars
...ime.datetime(2011, 1, 6, 0, 0)
]
x = date2num(x)
y = [4, 9, 2]
z = [1, 2, 3]
k = [11, 12, 13]
ax = plt.subplot(111)
ax.bar(x-0.2, y, width=0.2, color='b', align='center')
ax.bar(x, z, width=0.2, color='g', align='center')
ax.bar(x+0.2, k, width=0.2, color='r', align='center')
ax.xaxis_date()
plt....
Find the version of an installed npm package
... cli-color@0.1.6
│ └── es5-ext@0.7.1
├── coffee-script@1.3.3
├── less@1.3.0
├─┬ sentry@0.1.2
│ ├── file@0.2.1
│ └── underscore@1.3.3
└── uglify-js@1.2.6
You can also add --depth=0 argument to list installed packages without their dependencies...
C语言结构体里的成员数组和指针 - C/C++ - 清泛网 - 专注C/C++及内核技术
...去编译和调试，我把代码列在下面：
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#include <stdio.h>
struct str{
int len;
char s[0];
};
struct foo {
struct str *a;
};
int main(int argc, char** arg...
Find the most frequent number in a numpy vector
...ted/numpy.bincount.html
and then probably use np.argmax:
a = np.array([1,2,3,1,2,1,1,1,3,2,2,1])
counts = np.bincount(a)
print(np.argmax(counts))
For a more complicated list (that perhaps contains negative numbers or non-integer values), you can use np.histogram in a similar way. Alternatively, if ...
Interpolating a string into a regex
...
answered Sep 29 '08 at 18:53
Jonathan LonowskiJonathan Lonowski
108k3131 gold badges188188 silver badges191191 bronze badges
...
Delete the first three rows of a dataframe in pandas
...
Use iloc:
df = df.iloc[3:]
will give you a new df without the first three rows.
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Why is there no xrange function in Python3?
Recently I started using Python3 and it's lack of xrange hurts.
6 Answers
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