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Convert RGB to RGBA over white
I have a hex color, e.g. #F4F8FB (or rgb(244, 248, 251) ) that I want converted into an as-transparent-as-possible rgba color (when displayed over white). Make sense? I'm looking for an algorithm, or at least idea of an algorithm for how to do so.
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Can dplyr package be used for conditional mutating?
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Use ifelse
df %>%
mutate(g = ifelse(a == 2 | a == 5 | a == 7 | (a == 1 & b == 4), 2,
ifelse(a == 0 | a == 1 | a == 4 | a == 3 | c == 4, 3, NA)))
Added - if_else: Note that in dplyr 0.5 there is an if_else function defined so an alternative would be to replace ifelse with i...
How do I represent a hextile/hex grid in memory?
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156
Amit Patel has posted an amazing page on this topic. It's so comprehensive and wonderful that ...
How to get first character of a string in SQL?
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LEFT(colName, 1) will also do this, also. It's equivalent to SUBSTRING(colName, 1, 1).
I like LEFT, since I find it a bit cleaner, but really, there's no difference either way.
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SQL: capitalize first letter only [duplicate]
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190
Are you asking for renaming column itself or capitalise the data inside column? If its data yo...
Decreasing for loops in Python impossible?
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for n in range(6,0,-1):
print n
# prints [6, 5, 4, 3, 2, 1]
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How do I use floating-point division in bash?
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App Inventor 2 视频播放器教程 - VideoPlayer组件与WebView嵌入播放 · App Inventor 2 中文网
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三、支持的视频格式
四、播放本地视频
4.1 上传视频文件
4.2 代码控制播放
五、播放网络视频
5.1 设置网络视频源
5.2 使用 TextBox 让用户输入视频地址
六、VideoPlayer 属性详解
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Rotating a two-dimensional array in Python
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Consider the following two-dimensional list:
original = [[1, 2],
[3, 4]]
Lets break it down step by step:
>>> original[::-1] # elements of original are reversed
[[3, 4], [1, 2]]
This list is passed into zip() using argument unpacking, so the zip call ends...