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Assign multiple columns using := in data.table, by group
...b col1 col2
# 1: 1 1 hi hello
# 2: 2 2 hi hello
# 3: 3 3 hi hello
# 4: 1 4 hi hello
# 5: 2 5 hi hello
# 6: 3 6 hi hello
x[ , c("mean", "sum") := list(mean(b), sum(b)), by = a][]
# a b col1 col2 mean sum
# 1: 1 1 hi hello 2.5 5
# 2: 2 2 hi hello 3.5 7
# 3: 3 3 hi hello ...
Create Pandas DataFrame from a string
...StringIO
import pandas as pd
TESTDATA = StringIO("""col1;col2;col3
1;4.4;99
2;4.5;200
3;4.7;65
4;3.2;140
""")
df = pd.read_csv(TESTDATA, sep=";")
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How can I convert this foreach code to Parallel.ForEach?
...nse. Having said that, it's still a poor answer
– aw04
Sep 9 '16 at 14:29
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Using usort in php with a class private function
...tDemian Brecht
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Why does [5,6,8,7][1,2] = 8 in JavaScript?
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[1,2,3,4,5,6][1,2,3];
^ ^
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array + — array subscript access operation,
where index is `1,2,3`,
which is an expression that evaluates to `3`.
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How to convert byte array to Bitmap
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answered Oct 1 '11 at 13:41
UttamUttam
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