variable-assignment

Currently trying to understand the "^" operator in Elixir. From the website: The pin operator ^ can be used when there is no interest in rebinding a variable but rather in matching against its value prior to the match: Source - http://elixir-lang.org/getting_started/4.html With this in mind, you can attach a new value to a symbol like so: iex> x = 1 # Outputs "1" iex> x = 2 # Outputs "2" I can also do: iex> x = x + 1 # Outputs "3"! So my first question is; Are Elixir variables mutable? It sure looks like if that's the case... Shouldn't that be possible in a functional programming language? So

This is more of a conceptual question. I recently saw a piece of code in Python (it worked in 2.7, and it might also have been run in 2.5 as well) in which a for loop used the same name for both the list that was being iterated over and the item in the list, which strikes me as both bad practice and something that should not work at all. For example: x = [1,2,3,4,5] for x in x: print x print x Yields: 1 2 3 4 5 5 Now, it makes sense to me that the last value printed would be the last value assigned to x from the loop, but I fail to understand why you'd be able to use the same variable name for

How can I assign the same value for multiple variables in PHP at once ? I have something like: $var_a = 'A'; $var_b = 'A'; $same_var = 'A'; $var_d = 'A'; $some_var ='A'; In my case, I can't rename all variables to have the same name (that would make things more easy), so is there any way to assign the same value to all variables in a much more compact way? $var_a = $var_b = $same_var = $var_d = $some_var = 'A'; 来源： https://stackoverflow.com/questions/11651594/assign-same-value-to-multiple-variables-at-once

While looking at some Javascript code for Mozilla's (Firefox) Add-on SDK, I saw kind of variable declaration I hadn't seen before: var { foo, bar } = someFunction("whatever"); // just an example See those curly braces around the variable name? Turns out, this is a way of assigning the values of properties of an object to multiple variables all at once. It seems similar to destructuring assignment or PHP's list , except with object properties instead of arrays. I actually found this out through some fiddling, since there appears to be no documentation on it. Take a look at this code: function

I started working with go for a few weeks, and (once again) I stumbled across something that seems odd for me: // Not working a := 1 { a, b := 2, 3 } // Works a := 1 a, b := 2, 3 playground I want to assign two variables simultaneously. One is already declared, in a superior scope, the other one is not. It does not work: the compiler tries to redeclare the former variable. However, it works fine if this variable is declared in the same scope. Why is that ? What you're experiencing is commonly known as "variable shadowing" . When you use := with any variable in an inner scope, including in

The textbook examples of multiple unpacking assignment are something like: import numpy as NP M = NP.arange(5) a, b, c, d, e = M # so of course, a = 0, b = 1, etc. M = NP.arange(20).reshape(5, 4) # numpy 5x4 array a, b, c, d, e = M # here, a = M[0,:], b = M[1,:], etc. (ie, a single row of M is assigned each to a through e) (My question is not numpy specific. Indeed, I would prefer a pure Python solution.) For the piece of code I'm looking at now, I see two complications on that straightforward scenario: I usually won't know the shape of M; and I want to unpack a certain number of items