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Understanding dict.copy() - shallow or deep?
...ed by value, but just creating a new reference.
>>> a = {1: [1,2,3]}
>>> b = a.copy()
>>> a, b
({1: [1, 2, 3]}, {1: [1, 2, 3]})
>>> a[1].append(4)
>>> a, b
({1: [1, 2, 3, 4]}, {1: [1, 2, 3, 4]})
In contrast, a deep copy will copy all contents by value....
How to make good reproducible pandas examples
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341
Note: The ideas here are pretty generic for Stack Overflow, indeed questions.
Disclaimer: Wri...
Remove duplicated rows
...only need the first three columns
deduped.data <- unique( yourdata[ , 1:3 ] )
# the fourth column no longer 'distinguishes' them,
# so they're duplicates and thrown out.
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How to solve PHP error 'Notice: Array to string conversion in…'
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answered Nov 16 '13 at 10:43
jadkik94jadkik94
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How to extract the n-th elements from a list of tuples?
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edited Mar 6 '19 at 20:33
cs95
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Elegant way to invert a map in Scala
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answered Feb 25 '10 at 23:59
Daniel C. SobralDaniel C. Sobral
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Take the content of a list and append it to another list
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379
You probably want
list2.extend(list1)
instead of
list2.append(list1)
Here's the differen...
Apply pandas function to column to create multiple new columns?
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13 Answers
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App Inventor 2 数学积木的9个隐藏用法：随机种子、位运算、取整陷阱，踩中...
基础篇（1-3条）
技巧1：进制数字块直接写二进制和十六进制
别再用十进制再手动转换了。数字块本身就支持 0b 前缀写二进制、0x 前缀写十六进制、0o 前缀写八进制。比如 0b1010 直接就是 10，0xFF 就是 255。
更方便的是「...
Getting list of parameter names inside python function [duplicate]
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333
Well we don't actually need inspect here.
>>> func = lambda x, y: (x, y)
>>>...