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Using R to list all files with a specified extension

...f.files <- files[-grep(".xml", files, fixed=T)] First line just lists all files from working dir. Second one drops everything containing ".xml" (grep returns indices of such strings in 'files' vector; subsetting with negative indices removes corresponding entries from vector). "fixed" argument ...
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Gradle build without tests

... Try: gradle assemble To list all available tasks for your project, try: gradle tasks UPDATE: This may not seem the most correct answer at first, but read carefully gradle tasks output or docs. Build tasks ----------- assemble - Assembles the outputs...
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Why does NULL = NULL evaluate to false in SQL server

... I disagree that null signifies "unknown". What it actually means is "no data". That might be used to represent the case where information is not known, but it is actually more likely to be used to indicate that something doesn't exist. To continue your example: What is Frank's m...
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How to modify a text file?

... This is an operating system thing, not a Python thing. It is the same in all languages. What I usually do is read from the file, make the modifications and write it out to a new file called myfile.txt.tmp or something like that. This is better than reading the whole file into memory because the f...
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What is the naming convention in Python for variable and function names?

... C# background the naming convention for variables and method names are usually either camelCase or PascalCase: 13 Answers ...
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How to change a nullable column to not nullable in a Rails migration?

...s: # Make sure no null value exist MyModel.where(date_column: nil).update_all(date_column: Time.now) # Change the column to not allow null change_column :my_models, :date_column, :datetime, null: false share | ...
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Avoid trailing zeroes in printf()

...ing your number is in the variable num, the following function will remove all but the first N decimals, then strip off the trailing zeros (and decimal point if they were all zeros). char str[50]; sprintf (str,"%.20g",num); // Make the number. morphNumericString (str, 3); : : void morphNumericS...
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How to grep Git commit diffs or contents for a certain word?

In a Git code repository I want to list all commits that contain a certain word. I tried this 8 Answers ...
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Conceptually, how does replay work in a game?

... I think your initial thought was correct. To create a replay, you store all input received from the user (along with the frame number at which it was received) along with the initial seeds of any random number generators. To replay the game, you reset your PRNGs using the saved seeds and feed th...
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How to split text without spaces into list of words?

...el the distribution of the output. A good first approximation is to assume all words are independently distributed. Then you only need to know the relative frequency of all words. It is reasonable to assume that they follow Zipf's law, that is the word with rank n in the list of words has probabilit...