Fix clippy::len_zero

display/echo.rs

@@ -80,7 +80,7 @@ fn main() -> Result<(), Box<dyn std::error::Error>> {
     args.remove(0);
 
     let skip_nl = {
-        if args.len() > 0 && (args[0] == "-n") {
+        if !args.is_empty() && (args[0] == "-n") {
             args.remove(0);
             true
         } else {

file/file.rs

@@ -286,7 +286,7 @@ impl Type {
         };
 
         // the input string should be empty after all the steps being followed
-        if input.len() != 0 {
+        if !input.is_empty() {
             return Err(RawMagicLineParseError::InvalidTypeFormat);
         }
 

sys/who.rs

@@ -171,7 +171,7 @@ fn show_utmpx_summary() {
     let mut count = 0;
     let entries = plib::utmpx::load();
     for entry in &entries {
-        if entry.user.len() > 0 {
+        if !entry.user.is_empty() {
             println!("{}", entry.user);
             count += 1;
         }

text/diff_util/file_diff.rs

@@ -320,7 +320,7 @@ impl<'a> FileDiff<'a> {
             let ln2s = i64::clamp(cr.2 - context as i64, 1, f2_max as i64);
             let ln2e = i64::clamp(cr.3 + context as i64, 1, f2_max as i64);
 
-            if context_ranges.len() > 0 {
+            if !context_ranges.is_empty() {
                 // Overlap check
                 if let Some((_, ln1_end, _, ln2_end)) = context_ranges.last_mut() {
                     if *ln1_end >= ln1s as usize || *ln2_end >= ln2s as usize {

text/wc.rs

@@ -89,7 +89,7 @@ fn build_display_str(args: &Args, count: &CountInfo, filename: &OsStr) -> String
         output.push_str(&numstr);
     }
     if args.words {
-        if output.len() > 0 {
+        if !output.is_empty() {
             output.push(' ');
         }
         let numstr = match only_words {
@@ -99,7 +99,7 @@ fn build_display_str(args: &Args, count: &CountInfo, filename: &OsStr) -> String
         output.push_str(&numstr);
     }
     if args.bytes || args.chars {
-        if output.len() > 0 {
+        if !output.is_empty() {
             output.push(' ');
         }
         let numstr = match only_bytechars {