ruby inline if else assignment

m_x answer is perfect but you may be interested to know other ways to do it, which may look better in other circumstances: if params[:property] == nil then @item.property = true else @item.property = false end. or. @item.property = if params[:property] == nil then true else false end. answered Dec 8, 2012 at 12:30.

In the second if statement, because we used a single equals sign, the if statement actually uses the assignment operator. So the expression first assigns the value of 1 to x. ... Ruby provides a neat inline form for if/else statements, when the logic in your script is simple: num = -10 num += -1 if num < 0 puts num #=> -11. As opposed to: ...

Conditional assignment. Ruby is heavily influenced by lisp. One piece of obvious inspiration in its design is that conditional operators return values. This makes assignment based on conditions quite clean and simple to read. There are quite a number of conditional operators you can use. Optimize for readability, maintainability, and concision.

If something is true (the condition) then you can do something. In Ruby, you do this using if statements: stock = 10. if stock < 1. puts "Sorry we are out of stock!" end. Notice the syntax. It's important to get it right. The stock < 1 part is what we call a "condition".

Conditionals. if statements allow you to take different actions depending on which conditions are met. For example: if city == "Toronto" drinking_age = 19 else drinking_age = 21 end This says: if the city is equal to (==) "Toronto", then set drinking_age to 19.; Otherwise (else) set drinking_age; to 21.true and false. Ruby has a notion of true and false.

Just writing them all statements together in one line didn't work, and a syntax like if 5 == 5 {puts '5'} end didn't either. AFAIK, you can't use {} brackets to mark block for "if" statement, so. anything with them won't work. "If" uses "then" to mark beginning of its block and ends it with usual. "end".

This is because a single equal sign (=) is used for assignment in Ruby. So if we want to check if two values are equal, we need to use two equal signs. Ruby Unless Statement. Apart from the if statement, Ruby also has an unless statement that can be used to make decisions. The unless statement is the opposite of the if statement, meaning it ...

SyntaxError: invalid syntax. Most likely, the assignment in a conditional expression is a typo where the programmer meant to do a comparison == instead. This kind of typo is a big enough issue that there is a programming style called Yoda Conditionals , where the constant portion of a comparison is put on the left side of the operator.

Assignment from Conditionals. Another handy assignment feature: "x" elsif y. "y" elsif z. "z" end. result = "x" elsif y. result = "y" elsif z. result = "z" else result = nil end. You can also put the if on the same line as result = , but then you should probably indent everything underneath to line up (see: Indent Conditional Assignment ...

Control Expressions. Ruby has a variety of ways to control execution. All the expressions described here return a value. For the tests in these control expressions, nil and false are false-values and true and any other object are true-values. In this document "true" will mean "true-value" and "false" will mean "false-value".

In Ruby, we use the && ( AND) operator to separate the conditions we want to check are true. Here's an example of an if statement with multiple conditions: if user_discount = = true && age < 5 // Run code. End. We can use the && operator as many times as we want to check if a certain statement evaluates to be true.

That's part of the syntax! It's how Ruby knows that you're writing a ternary operator. Next: We have whatever code you want to run if the condition turns out to be true, the first possible outcome. Then a colon (: ), another syntax element. Lastly, we have the code you want to run if the condition is false, the second possible outcome.

A common pattern is to use an inline, or trailing, if or unless: puts "x is less than 5" if x < 5. This is known as a conditional modifier, and is a handy way of adding simple guard code and early returns: def save_to_file(data, filename) raise "no filename given" if filename.empty? return false unless data.valid? File.write(filename, data) end.

Assignment. In Ruby, assignment uses the = (equals sign) character. This example assigns the number five to the local variable v: v = 5. Assignment creates a local variable if the variable was not previously referenced. An assignment expression result is always the assigned value, including assignment methods.

The built-in if-then-else syntax is inline: the expression if predicate then expr1 else expr2. has type ... A traditional if-else construct in Ruby is written: if a > b result = x else result = y end. This could also be written as: ... // using blocking assignment wire out; if ...

The Github Ruby Styleguide recommends that one liners be reserved for trivial if/else statements and that nested ternary operators be avoided. You could use the then keyword but its considered bad practice. if foo then 'a' elsif bar then 'b' else 'c' end. You could use cases (ruby's switch operator) if find your control statements overly complex.

The syntax is just like an if-block. i = 4 # Use an unless-else construct. unless i == 3 puts "UNLESS" else puts "ELSE" end UNLESS. Unless, one line. An unless modifier can also be used on one line. This syntax makes programs readable, almost like English: you take a certain action unless a condition is true.

It is the ternary operator, and it works like in C (the parenthesis are not required).It's an expression that works like: if_this_is_a_true_value ? then_the_result_is_this : else_it_is_this However, in Ruby, if is also an expression so: if a then b else c end === a ? b : c, except for precedence issues.Both are expressions.

Ruby has an or-equals operator that allows a value to be assigned to a variable if and only if that variable evaluates to either nil or false. ||= # this is the operator that achieves this. this operator with the double pipes representing or and the equals sign representing assigning of a value. You may think it represents something like this: