Kaplan questions

Kaplan answers

• `.ok_or()` works but `.ok_or_else()` doesn't work even the type signature is the same
• How to get strings parsed to floats with comma as decimal separator
• Peek iterator inside `for` loop
• How do I create an nalgebra static matrix by copying from a dynamic matrix view?
• How to take ownership of Any:downcast_ref from trait object?
• Why does Iterator::take_while take ownership of the iterator?
• Why does my CompletableFuture code run in Java 8 but not in Java 11?
• Conversion of collection to int array
• Make a string from an IntStream of code point numbers?
• How to remove first and last character of a string in Rust?