Variables declared inside an if statement results

问题:

I was hoping that defining variables in an if statement would work in Sass but unfortunately I get errors saying that the variable isn't defined. Here is what I tried:

@for !i from 1 through 9
    !foo = #000
    @if !i == 1
        !bg_color = #009832
    @if !i == 2
        !bg_color = #195889
    ...

    #bar#{!i} 
        color: #{!foo}
        background-color: #{!bg_color}

With this code, I would get the following error:

Undefined variable: "!bg_color".

回答1:

Sass variables are only visible to the level of indentation at which they are declared and those nested underneath it. So you only need to declare !bg_color outside of your for loop:

!bg_color = #FFF
@for !i from 1 through 9
    !foo = #000
    @if !i == 1
        !bg_color = #009832
    @if !i == 2
        !bg_color = #195889

    #bar#{!i} 
        color: #{!foo}
        background-color: #{!bg_color}

And you'll get the following css:

#bar1 {
  color: black;
  background-color: #009832; }

#bar2 {
  color: black;
  background-color: #195889; }

#bar3 {
  color: black;
  background-color: #195889; }

#bar4 {
  color: black;
  background-color: #195889; }

#bar5 {
  color: black;
  background-color: #195889; }

#bar6 {
  color: black;
  background-color: #195889; }

#bar7 {
  color: black;
  background-color: #195889; }

#bar8 {
  color: black;
  background-color: #195889; }

#bar9 {
  color: black;
  background-color: #195889; }