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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 ...
Setting up two different static directories in node.js Express framework
...nal (first) parameter to use() like so:
app.use("/public", express.static(__dirname + "/public"));
app.use("/public2", express.static(__dirname + "/public2"));
That way you get two different directories on the web that mirror your local directories, not one url path that fails over between two lo...
Maximum number of records in a MySQL database table
... The poster is not asking about numeric or any other data types. . I really do not understand how this can be flagged as a correct answer. Though I must admit that the question is ambiguous we should distinguish between PK data type and maximum number of rows for a table.
–...
What's the meaning of interface{}?
...interface that has no methods.
Since there is no implements keyword, all types implement at least zero methods, and satisfying an interface is done automatically, all types satisfy the empty interface.
That means that if you write a function that takes an interface{} value as a parameter, yo...
How to iterate for loop in reverse order in swift?
... an array with one trillion Ints!
Test:
var count = 0
for i in lazy(1...1_000_000_000_000).reverse() {
if ++count > 5 {
break
}
println(i)
}
For Swift 2.0 in Xcode 7:
for i in (1...10).reverse() {
print(i)
}
Note that in Swift 2.0, (1...1_000_000_000_000).reverse(...
cpuid汇编指令 - C/C++ - 清泛网 - 专注C/C++及内核技术
... cpuid
cmp eax, 80000004h
jb not_supported
mov di, offset CPU_name
mov eax, 80000002h
cpuid
call save_string
mov eax, 80000003h
cpuid
...
Why compile Python code?
...ou invoke with python main.py is recompiled every time you run the script. All imported scripts will be compiled and stored on the disk.
Important addition by Ben Blank:
It's worth noting that while running a
compiled script has a faster startup
time (as it doesn't need to be
compiled), i...
FormData.append(“key”, “value”) is not working
...rmdata.get(key)
and more very useful methods
Original answer:
What I usually do to 'debug' a FormData object, is just send it (anywhere!) and check the browser logs (eg. Chrome devtools' Network tab).
You don't need a/the same Ajax framework. You don't need any details. Just send it:
var xhr = ...
What is the correct way to make a custom .NET Exception serializable?
More specifically, when the exception contains custom objects which may or may not themselves be serializable.
7 Answers
...
Slicing of a NumPy 2d array, or how do I extract an mxm submatrix from an nxn array (n>m)?
... with x[numpy.ix_([0,2],[1,3])]. This can save you from having to enter in all of those extra brackets.
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