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| <title>R Breakpoints - Condition / Expression Property</title> |
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| <h1 class="Head">Condition / Expression Property of R Breakpoints</h1> |
| |
| <p>Each breakpoint can have a unique condition that determines if the will be suspended at the |
| breakpoint position. A conditional breakpoint has a question mark overlay on its icon.</p> |
| |
| <p>A condition for a breakpoint can be any valid R expression. The expression is evaluated in the |
| scope (R frame) of the breakpoint location. If it evaluates to an atomic R logical value |
| <code>TRUE</code>, the thread is suspended as usual. Otherwise it is skipped like a disabled |
| breakpoint.</p> |
| |
| <img alt="Screenshot conditional breakpoint in R editor and Breakpoint view" |
| src="../images/screenshot-breakpoints-condition.png"/> |
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| <!-- TODO: add example --> |
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| <h4>Changing the Settings</h4> |
| |
| <p>A condition can be set, enabled/disabled and removed in the Breakpoint view. |
| </p> |
| <ol> |
| <li>Select the breakpoint to change.<br/> |
| The Breakpoint view shows properties supported by the selected breakpoint in the |
| detail pane below or beside the breakpoints list. |
| </li> |
| <li>The checkbox <span class="uisequence">Conditional / Expression</span> allows to enable and |
| disable the condition. |
| </li> |
| <li>If the checkbox is enabled, the user can enter the expression of the condition in the |
| text field below. The common Save command (<span class="uisequence">File > Save</span>) |
| applies the changed expression to the breakpoint; it is also automatically saved when |
| selecting another breakpoint. |
| </li> |
| </ol> |
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