diff --git a/src/expr/syntax_tree.rs b/src/expr/syntax_tree.rs
index a42c42717..be668baec 100644
--- a/src/expr/syntax_tree.rs
+++ b/src/expr/syntax_tree.rs
@@ -487,10 +487,7 @@ fn prefix_operator_index(values: &[String]) -> Result<String, String> {
     let haystack = &values[0];
     let needles = &values[1];
 
-    let mut current_idx = 0;
-    for ch_h in haystack.chars() {
-        current_idx += 1;
-
+    for (current_idx, ch_h) in haystack.chars().enumerate() {
         for ch_n in needles.chars() {
             if ch_n == ch_h {
                 return Ok(current_idx.to_string());
diff --git a/src/printf/tokenize/num_format/formatters/base_conv/mod.rs b/src/printf/tokenize/num_format/formatters/base_conv/mod.rs
index cc1d45007..59987b850 100644
--- a/src/printf/tokenize/num_format/formatters/base_conv/mod.rs
+++ b/src/printf/tokenize/num_format/formatters/base_conv/mod.rs
@@ -226,13 +226,11 @@ pub fn base_conv_float(src: &[u8], radix_src: u8, radix_dest: u8) -> f64 {
     result.push(0);
     let mut factor: f64 = 1_f64;
     let radix_src_float: f64 = f64::from(radix_src);
-    let mut i = 0;
     let mut r: f64 = 0_f64;
-    for u in src {
+    for (i, u) in src.iter().enumerate() {
         if i > 15 {
             break;
         }
-        i += 1;
         factor /= radix_src_float;
         r += factor * f64::from(*u)
     }