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Can dplyr package be used for conditional mutating?
...and the conditions (except for the default value of NA at the end) are mutually exclusive, as is the case in the question, then we can use an arithmetic expression such that each term is multiplied by the desired result using na_if at the end to replace 0 with NA.
df %>%
mutate(g = 2 * (a == 2 ...
Fastest Way to Serve a File Using PHP
...erywhere.
Using the X-SendFile header
As documented by others it's actually the best way. The basis is that you do your access control in php and then instead of sending the file yourself you tell the web server to do it.
The basic php code is :
header("X-Sendfile: $file_name");
header("Conten...
Programmatically change UITextField Keyboard type
...
_textField .keyboardType = UIKeyboardTypeAlphabet;
_textField .keyboardType = UIKeyboardTypeASCIICapable;
_textField .keyboardType = UIKeyboardTypeDecimalPad;
_textField .keyboardType = UIKeyboardTypeDefault;
_textField .keyb...
What is INSTALL_PARSE_FAILED_NO_CERTIFICATES error?
I was trying to change my default/main/startup (whatever you call it) activity by editing the androidmanifest.xml file. All i did was change the android:name property. however, this completely broke the entire app. when I try to install it fails and reads.
...
Illegal pattern character 'T' when parsing a date string to java.util.Date
...ant.parse("2015-04-28T14:23:38.521Z") and get the correct thing now, especially since you should be using Instant instead of the broken java.util.Date with the most recent versions of Java.
You should be using DateTimeFormatter instead of SimpleDateFormatter as well.
Original Answer:
The expl...
Automatically add newline at end of curl response body
...or a curl request doesn't contain a trailing newline, I end up with this really annoying condition where the shell prompt is in the middle of the line, and escaping is messed up enough that when I put the last curl command on the screen, deleting characters from that curl command deletes the wrong c...
Is there a max array length limit in C++?
...se memory is full. For example, a vector<int> of a given size n typically takes multiple times as much memory as an array of type vector<char> (minus a small constant value), since int is usually bigger than char. Therefore, a vector<char> may contain more items than a vector<in...
Check OS version in Swift?
...OS8 = floor(NSFoundationVersionNumber) > floor(NSFoundationVersionNumber_iOS_7_1)
let iOS7 = floor(NSFoundationVersionNumber) <= floor(NSFoundationVersionNumber_iOS_7_1)
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What is TypeScript and why would I use it in place of JavaScript? [closed]
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I originally wrote this answer when TypeScript was still
hot-off-the-presses. Five years later, this is an OK overview, but look
at Lodewijk's answer below for more depth
1000ft view...
TypeScript is a superset of JavaScript ...
Print in one line dynamically
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From http://docs.python.org/reference/simple_stmts.html#print: > A '\n' character is written at the end, unless the print statement ends with a comma. This is the only action if the statement contains just the keyword print.
– ewall
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