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How to use sed to replace only the first occurrence in a file?
...pression #1, char 0: no previous regular expression (GNU), because, at the time the 1st line is being processed (due to line number 1 starting the range), no regex has been applied yet, so // doesn't refer to anything.
With the exception of GNU sed's special 0,/re/ syntax, any range that starts with...
Combine two columns of text in pandas dataframe
... without CPU/GPU optimization (sorted from fastest to slowest):
In [107]: %timeit df['Year'].astype(str) + df['quarter']
10 loops, best of 3: 131 ms per loop
In [106]: %timeit df['Year'].map(str) + df['quarter']
10 loops, best of 3: 161 ms per loop
In [108]: %timeit df.Year.str.cat(df.quarter)
10 ...
How to define hash tables in Bash?
...re to another list of keys, instead of O(n) with proper hashmaps (constant time lookup, O(1) for a single key).
– CodeManX
Aug 23 '15 at 19:01
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How can I parse a YAML file from a Linux shell script?
...r my use case, since it answered the question better than any other at the time. This can definitely be expanded.
– Curtis Blackwell
Nov 27 '13 at 13:37
3
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What is your favorite C programming trick? [closed]
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I sometimes extend this to: const struct something zero_something = { 0 }; and then I can reset a variable on the fly with struct something X = zero_something; or part-way through a routine I can use 'X = zero_something;'. The onl...
Find intersection of two nested lists?
... The average case of "val in s2" is O(1) according to wiki.python.org/moin/TimeComplexity#set - thus over n operations the expected time is O(n) (whether the worst-case time is O(n) or O(n^2) depends on whether this average case represents an amortized time or not, but this isn't very important in p...
Confused about Service vs Factory
... to it. And that a factory was a singleton that returned a new object each time. That is, a service would give you one "car" and everything in your project would use this car. While a factory would give you a new car each time you invoked the factory. One was a singleton that returned a singleton an...
Timeout a command in bash without unnecessary delay
... to Command line command to auto-kill a command after a certain amount of time
23 Answers
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How to get a password from a shell script without echoing
...s] [-a array] [-d delim] [-i text] [-n nchars] [-N nchars] [-p prompt] [-t timeout] [-u fd] [name ...]
Read a line from the standard input and split it into fields.
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-p prompt output the string PROMPT without a trailing newline before
attempting to read
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-s d...
What does “not run” mean in R help pages?
Sometimes on an R help page the phrase "not run" appears in comments. Check out this from the help page for "with()":
5 Ans...