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grep using a character vector with multiple patterns
I am trying to use grep to test whether a vector of strings are present in an another vector or not, and to output the values that are present (the matching patterns).
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Comment the interface, implementation or both?
I imagine that we all (when we can be bothered!) comment our interfaces. e.g.
9 Answers
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Reference - What does this error mean in PHP?
This is a number of answers about warnings, errors, and notices you might encounter while programming PHP and have no clue how to fix them. This is also a Community Wiki, so everyone is invited to participate adding to and maintaining this list.
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What happens when a duplicate key is put into a HashMap?
... original value? And what if even the value repeats? I didn’t find any documentation on this.
12 Answers
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Test for non-zero length string in Bash: [ -n “$var” ] or [ “$var” ]
I've seen Bash scripts test for a non-zero length string in two different ways. Most scripts use the -n option:
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List comprehension vs map
Is there a reason to prefer using map() over list comprehension or vice versa? Is either of them generally more efficient or considered generally more pythonic than the other?
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Determining the last changelist synced to in Perforce
A question that occasionally arises is what is the best way to determine the changelist that you last synced to in Perforce. This is often needed for things like injecting the changelist number into the revision info by the automatic build system.
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How can I get Git to follow symlinks?
Is my best be going to be a shell script which replaces symlinks with copies, or is there another way of telling Git to follow symlinks?
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How do I parse an ISO 8601-formatted date?
I need to parse RFC 3339 strings like "2008-09-03T20:56:35.450686Z" into Python's datetime type.
27 Answers
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What is the difference between a Docker image and a container?
When using Docker, we start with a base image. We boot it up, create changes and those changes are saved in layers forming another image.
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