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//! This is a bare-bones alternative to the `thousands` crate on crates.io, for
//! printing large numbers in a readable fashion.
#[cfg(test)]
mod tests;
fn format_with_underscores(mut s: String) -> String {
// Ignore a leading '-'.
let start = if s.starts_with('-') { 1 } else { 0 };
// Stop after the first non-digit, e.g. '.' or 'e' for floats.
let non_digit = s[start..].find(|c: char| !c.is_digit(10));
let end = if let Some(non_digit) = non_digit { start + non_digit } else { s.len() };
// Insert underscores within `start..end`.
let mut i = end;
while i > start + 3 {
i -= 3;
s.insert(i, '_');
}
s
}
/// Print a `usize` with underscore separators.
pub fn usize_with_underscores(n: usize) -> String {
format_with_underscores(format!("{n}"))
}
/// Print an `isize` with underscore separators.
pub fn isize_with_underscores(n: isize) -> String {
format_with_underscores(format!("{n}"))
}
/// Print an `f64` with precision 1 (one decimal place) and underscore separators.
pub fn f64p1_with_underscores(n: f64) -> String {
format_with_underscores(format!("{n:.1}"))
}
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