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Extract first item of each sublist
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Using list comprehension:
>>> lst = [['a','b','c'], [1,2,3], ['x','y','z']]
>>> lst2 = [item[0] for item in lst]
>>> lst2
['a', 1, 'x']
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Need a simple explanation of the inject method
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edited Apr 2 '09 at 16:37
answered Apr 2 '09 at 16:31
Dr...
Finding all possible combinations of numbers to reach a given sum
...ning, target, partial + [n])
if __name__ == "__main__":
subset_sum([3,9,8,4,5,7,10],15)
#Outputs:
#sum([3, 8, 4])=15
#sum([3, 5, 7])=15
#sum([8, 7])=15
#sum([5, 10])=15
This type of algorithms are very well explained in the following Standford's Abstract Programming lec...
pandas: How do I split text in a column into multiple rows?
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This splits the Seatblocks by space and gives each its own row.
In [43]: df
Out[43]:
CustNum CustomerName ItemQty Item Seatblocks ItemExt
0 32363 McCartney, Paul 3 F04 2:218:10:4,6 60
1 31316 Lennon, John 25 F01 1:13:36:1...
莱昂氏unix源代码分析 PDF - 文档下载 - 清泛网 - 专注C/C++及内核技术
...篇 UNIX操作系统版本6源代码
UNIX操作系统过程分类索引 3
UNIX操作系统文件及过程 5
UNIX操作系统定义的符号列表 7
UNIX操作系统源代码交叉引用列表 9
第一部分 初始化、进程初始化 25
第二部分 陷入、中断、系统调用和
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How do I get indices of N maximum values in a NumPy array?
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365
The simplest I've been able to come up with is:
In [1]: import numpy as np
In [2]: arr = np....
Reorder levels of a factor without changing order of values
...f <- data.frame(f = 1:4, g = letters[1:4])
df
# f g
# 1 1 a
# 2 2 b
# 3 3 c
# 4 4 d
levels(df$g)
# [1] "a" "b" "c" "d"
df$g <- factor(df$g, levels = letters[4:1])
# levels(df$g)
# [1] "d" "c" "b" "a"
df
# f g
# 1 1 a
# 2 2 b
# 3 3 c
# 4 4 d
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Plot a legend outside of the plotting area in base graphics?
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113
Maybe what you need is par(xpd=TRUE) to enable things to be drawn outside the plot region. So if...
How do I find the duplicates in a list and create another list with them?
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34 Answers
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What are the mathematical/computational principles behind this game?
...nd you have the question:
Can we have a geometry with just 2 points? With 3 points? With 4? With 7?
There are still open questions regarding this problem but we do know this:
If there are geometries with Q points, then Q = n^2 + n + 1 and n is called the order of the geometry.
There are n+1 poin...