variable-assignment

I'm learning to program and I am using Python to start. In there, I see that I can do something like this: >>>> def myFunction(): return 1 >>>> test = myFunction >>>> test() 1 However, if I try and do the same with print it fails: >>>> test2 = print File "<stdin>", line 1 test2 = print ^ SyntaxError: invalid syntax Why is print different than a function I create? This is using Python v2.7.5. BrenBarn print is a statement , not a function. This was changed in Python 3 partly to allow you to do things like this. In Python 2.7 you can get print as a function by doing from __future__ import print

I am wondering how assignment works in the R language. Consider the following R shell session: > x <- c(5, 6, 7) > x[1] <- 10 > x [1] 10 6 7 > which I totally understand. The vector (5, 6, 7) is created and bound to the symbol 'x'. Later, 'x' is rebound to the new vector (10, 6, 7) because vectors are immutable data structures. But what happens here: > c(4, 5, 6)[1] <- 10 Error in c(4, 5, 6)[1] <- 10 : target of assignment expands to non-language object > or here: > f <- function() c(4, 5, 6) > f()[1] <- 10 Error in f()[1] <- 10 : invalid (NULL) left side of assignment > It seems to me that

In a for-comprehension, I can't just put a print statement: def prod (m: Int) = { for (a <- 2 to m/(2*3); print (a + " "); b <- (a+1) to m/a; c = (a*b) if (c < m)) yield c } but I can circumvent it easily with a dummy assignment: def prod (m: Int) = { for (a <- 2 to m/(2*3); dummy = print (a + " "); b <- (a+1) to m/a; c = (a*b) if (c < m)) yield c } Being a side effect, and only used (so far) in code under development, is there a better ad hoc solution? Is there a serious problem why I shouldn't use it, beside being a side effect? update showing the real code, where adapting one solution is

Is it considered bad style to assign values to variables like this? x = "foobar" or None y = some_variable or None In the above example, x gets the value 'foobar'. No, it's a common practice. It's only considered bad style for expressions that are considerably longer than yours. The primary danger of doing something like this is the possibility that (in the second case) some_variable is False but not None (the integer 0 , for instance) and you don't want to end up with y equal to None in that case. I also feel a bit unconfortable using that kind of expressions. In Learning Python 4ed it is

I'm testing an expression with two inequalities for the condition of a list comprehension. Is there a way to have assignments here and not duplicate that expression? (The following code doesn't work, but I wish it would) diagnose(Expertise,PatientSymptoms)-> {[CertainDisease|| {CertainDisease,KnownSymptoms}<-Expertise, C=length(PatientSymptoms)-length(PatientSymptoms--KnownSymptoms), C>=2, C<=5 ]}. A way of writing it directly without a fun would be to use a begin ... end block ending with a boolean test: [ CertainDisease || {CertainDisease,KnownSymptoms} <- Expertise, begin C = length

Working with React.js and React Router import React, { Component } from 'react'; const PrivateRoute = ({ component: Component, ...rest }) => ( <Route {...rest} render={} /> ) *{ component: Component, ...rest }* ..rest is the use of spread syntax but what does *component: Component* do Suman Kundu In ES6 this will assign the value to a new variable in this case named foo let obj = { name: 'Some Name', age: '42', gender: 'coder' }; let { name: foo, ...rest } = obj; console.log({foo, rest}) // { foo: 'Some Name', rest: { age: 42, gender: 'coder' } } // In this case, name will not be defined for