Replace for with forEach

src/main/java/org/apache/commons/math4/random/RandomUtils.java

@@ -260,8 +260,8 @@ public String nextHexString(int len,
                     final byte[] hash = alg.digest();
 
                     // Loop over the hash, converting each byte to 2 hex digits
-                    for (int i = 0; i < hash.length; i++) {
-                        final Integer c = Integer.valueOf(hash[i]);
+                    for (byte hash1 : hash) {
+                        final Integer c = Integer.valueOf(hash1);
 
                         // Add 128 to byte value to make interval 0-255.
                         // This guarantees <= 2 hex digits from "toHexString".

src/main/java/org/apache/commons/math4/stat/StatUtils.java

@@ -746,8 +746,8 @@ public static double[] normalize(final double[] sample) {
         DescriptiveStatistics stats = new DescriptiveStatistics();
 
         // Add the data from the series to stats
-        for (int i = 0; i < sample.length; i++) {
-            stats.addValue(sample[i]);
+        for (double v : sample) {
+            stats.addValue(v);
         }
 
         // Compute mean and standard deviation

src/main/java/org/apache/commons/math4/stat/regression/MillerUpdatingRegression.java

@@ -942,8 +942,8 @@ public RegressionResults regress(int numberOfRegressors) throws ModelSpecificati
         double[] cov = this.cov(numberOfRegressors);
 
         int rnk = 0;
-        for (int i = 0; i < this.lindep.length; i++) {
-            if (!this.lindep[i]) {
+        for (boolean b : this.lindep) {
+            if (!b) {
                 ++rnk;
             }
         }
@@ -1034,9 +1034,9 @@ public RegressionResults regress(int[] variablesToInclude) throws ModelSpecifica
         if (iExclude > 0) {
             int j = 0;
             series = new int[variablesToInclude.length - iExclude];
-            for (int i = 0; i < variablesToInclude.length; i++) {
-                if (variablesToInclude[i] > -1) {
-                    series[j] = variablesToInclude[i];
+            for (int i1 : variablesToInclude) {
+                if (i1 > -1) {
+                    series[j] = i1;
                     ++j;
                 }
             }

src/main/java/org/apache/commons/math4/stat/regression/SimpleRegression.java

@@ -256,12 +256,12 @@ public void removeData(final double x,final double y) {
      * greater than or equal to 2
      */
     public void addData(final double[][] data) throws ModelSpecificationException {
-        for (int i = 0; i < data.length; i++) {
-            if( data[i].length < 2 ){
-               throw new ModelSpecificationException(LocalizedFormats.INVALID_REGRESSION_OBSERVATION,
-                    data[i].length, 2);
+        for (double[] datum : data) {
+            if (datum.length < 2) {
+                throw new ModelSpecificationException(LocalizedFormats.INVALID_REGRESSION_OBSERVATION,
+                        datum.length, 2);
             }
-            addData(data[i][0], data[i][1]);
+            addData(datum[0], datum[1]);
         }
     }
 
@@ -301,8 +301,8 @@ public void addObservations(final double[][] x,final double[] y) throws ModelSpe
                   (y == null) ? 0 : y.length);
         }
         boolean obsOk=true;
-        for( int i = 0 ; i < x.length; i++){
-            if( x[i] == null || x[i].length == 0 ){
+        for (double[] x1 : x) {
+            if (x1 == null || x1.length == 0) {
                 obsOk = false;
             }
         }

src/main/java/org/apache/commons/math4/util/CompositeFormat.java

@@ -148,8 +148,8 @@ public static Number parseNumber(final String source, final NumberFormat format,
             final double[] special = {
                 Double.NaN, Double.POSITIVE_INFINITY, Double.NEGATIVE_INFINITY
             };
-            for (int i = 0; i < special.length; ++i) {
-                number = parseNumber(source, special[i], pos);
+            for (double v : special) {
+                number = parseNumber(source, v, pos);
                 if (number != null) {
                     break;
                 }

src/main/java/org/apache/commons/math4/util/MathArrays.java

@@ -1244,9 +1244,9 @@ public static double[] concatenate(double[] ...x) {
         int offset = 0;
         int curLength = 0;
         final double[] combined = new double[combinedLength];
-        for (int i = 0; i < x.length; i++) {
-            curLength = x[i].length;
-            System.arraycopy(x[i], 0, combined, offset, curLength);
+        for (double[] x1 : x) {
+            curLength = x1.length;
+            System.arraycopy(x1, 0, combined, offset, curLength);
             offset += curLength;
         }
         return combined;