Anchor UIButton to the left of a UILabel

I have a UILabel with right-aligned text that may vary from between three to seven characters in length. I am trying to anchor a button to the left of this text so that when the length of the text 开发者_如何学Goincreases, the button will stay the same distance from the left of the label.

Is there an anchor setting in Interface Builder, or does it require a code-level solution (e.g. setting the button's x position according to the width of the label)?

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You need to do this in code. Interface builder is not build for runtime calculations.

To calculate the width of your text you can use NSString's sizeWithFont: method.