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Single Line Nested For Loops
...hension (here (x,y)):
>>> [(x, y) for x in [1,2,3] for y in [3,1,4] if x != y]
[(1, 3), (1, 4), (2, 3), (2, 1), (2, 4), (3, 1), (3, 4)]
It's exactly the same as this nested for loop (and, as the tutorial says, note how the order of for and if are the same).
>>> combs = []
>&...
Pandas dataframe get first row of each group
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248
>>> df.groupby('id').first()
value
id
1 first
2 first
3 first
4 ...
MySql: Tinyint (2) vs tinyint(1) - what is the difference?
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4 Answers
4
Active
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How to write multiple line string using Bash with variables?
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480
The syntax (<<<) and the command used (echo) is wrong.
Correct would be:
#!/bin/bas...
Active Record - Find records which were created_at before today
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4 Answers
4
Active
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Order data frame rows according to vector with specific order
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Try match:
df <- data.frame(name=letters[1:4], value=c(rep(TRUE, 2), rep(FALSE, 2)))
target <- c("b", "c", "a", "d")
df[match(target, df$name),]
name value
2 b TRUE
3 c FALSE
1 a TRUE
4 d FALSE
It will work as long as your target contains exactly...
How to swap keys and values in a hash
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edited Jan 14 at 0:20
the Tin Man
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Split delimited strings in a column and insert as new rows [duplicate]
... of doing it..
df <- read.table(textConnection("1|a,b,c\n2|a,c\n3|b,d\n4|e,f"), header = F, sep = "|", stringsAsFactors = F)
df
## V1 V2
## 1 1 a,b,c
## 2 2 a,c
## 3 3 b,d
## 4 4 e,f
s <- strsplit(df$V2, split = ",")
data.frame(V1 = rep(df$V1, sapply(s, length)), V2 = unlist(...
Overload constructor for Scala's Case Classes?
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retronymretronym
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