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Split data frame string column into multiple columns
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291
Use stringr::str_split_fixed
library(stringr)
str_split_fixed(before$type, "_and_", 2)
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Calculating sum of repeated elements in AngularJS ng-repeat
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answered Mar 29 '14 at 12:53
VamsiVamsi
8,20433 gold badges3333 silver badges4343 bronze badges
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How to convert 2D float numpy array to 2D int numpy array?
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Use the astype method.
>>> x = np.array([[1.0, 2.3], [1.3, 2.9]])
>>> x
array([[ 1. , 2.3],
[ 1.3, 2.9]])
>>> x.astype(int)
array([[1, 2],
[1, 2]])
share
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how to calculate binary search complexity
...rer as informal ones:
The question is, how many times can you divide N by 2 until you have 1? This is essentially saying, do a binary search (half the elements) until you found it. In a formula this would be this:
1 = N / 2x
multiply by 2x:
2x = N
now do the log2:
log2(2x) = l...
How to validate phone numbers using regex
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42 Answers
42
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Fastest way to iterate over all the chars in a String
...(not advised), read this first: http://www.javaspecialists.eu/archive/Issue237.html
Starting from Java 9, the solution as described won't work anymore, because now Java will store strings as byte[] by default.
SECOND UPDATE: As of 2016-10-25, on my AMDx64 8core and source 1.8, there is no difference...
Programmatically obtain the Android API level of a device?
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answered Nov 2 '14 at 11:01
Arkadiusz CieślińskiArkadiusz Cieśliński
4,96933 gold badges1919 silver badges1818 bronze badges
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Javascript roundoff number to nearest 0.5
...en resolution and for that i can only assign font size in pts to 1, 1.5 or 2 and onwards etc.
7 Answers
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[since C++11] std::array的使用 - C/C++ - 清泛网 - 专注C/C++及内核技术
...有虚函数.
因此不支持这样的构造方法：array<int, 3> a({1, 2, 4});
初始化array最常用的方法是使用赋值运算符和初始化列表：
array<int, 3> a = {1, 2, 3};
array<int, 100> b = {1, 2, 3}; // a[0] ~ a[2] = 1, 2, 3; a[3] ~ a[99] = 0, 0, 0 ... 0;
array<int, 3> c; ...