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(Built-in) way in JavaScript to check if a string is a valid number
...ter-intuitive. +num converts empty strings or strings with spaces to zero, and isNaN() assumes the same:
+'' // 0
+' ' // 0
isNaN('') // false
isNaN(' ') // false
But parseInt() does not agree:
parseInt('') // NaN
parseInt(' ') // NaN
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How can I echo a newline in a batch file?
... The period thing in "echo." never stops amazing me. It's so dated, and still I always forget that the dot must be strictly concatenated with the command name, with no spaces between. There's no error in the post of yours, I'm writing this just as a reminder: "echo ." != "echo." !
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How do I determine if a port is open on a Windows server? [closed]
...e default option 'telnet' is not recognized as an internal or external command, operable program or batch file. To solve this, just enable it: Click *Start** → Control Panel → Programs → Turn Windows Features on or off. In the list, scroll down and select Telnet Client and click OK.
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Windows recursive grep command-line
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findstr can do recursive searches (/S) and supports some variant of regex syntax (/R).
C:\>findstr /?
Searches for strings in files.
FINDSTR [/B] [/E] [/L] [/R] [/S] [/I] [/X] [/V] [/N] [/M] [/O] [/P] [/F:file]
[/C:string] [/G:file] [/D:dir list] [/A...
What does “while True” mean in Python?
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while True means loop forever. The while statement takes an expression and executes the loop body while the expression evaluates to (boolean) "true". True always evaluates to boolean "true" and thus executes the loop body indefinitely. It's an idiom that you'll just get used to eventually! Most ...
How to read a line from the console in C?
... line in a C console program
The text entered might have a variable length and we can't make any assumption about its content.
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How to get .app file of a xcode application
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Build a release version, and the .app file is under build/Release folder of your project. Just copy it to Applications folder of your friend's machine. I don't think you need to build a installer.
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How do I encode and decode a base64 string?
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Null checks for input strings in both functions and the solution is perfect :)
– Sverrir Sigmundarson
Mar 29 '14 at 23:05
24
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How to check if a variable is an integer in JavaScript?
How do I check if a variable is an integer in JavaScript, and throw an alert if it isn't? I tried this, but it doesn't work:
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Add leading zeroes/0's to existing Excel values to certain length
There are many, many questions and quality answers on SO regarding how to prevent leading zeroes from getting stripped when importing to or exporting from Excel. However, I already have a spreadsheet that has values in it that were truncated as numbers when, in fact, they should have been handled a...