csv: added slice type to CSV

Author: Adwaith-Rajesh

include/parsers/csv.h

@@ -53,6 +53,11 @@ typedef struct {
     char delim;
 } CSV;
 
+typedef struct {
+    size_t lower;
+    size_t upper;  // non inclusive
+} Slice;
+
 /*
 Initialize the CSV reader/parser
 
@@ -80,4 +85,10 @@ Returns a new Mat with only the selected cols
 */
 Mat *csv_get_mat(CSV *csv, int *rows, size_t c_size);
 
+/*
+Returns a new Mat with only the selected cols using Slice type
+*/
+
+Mat *csv_get_mat_slice(CSV *csv, Slice slice);
+
 #endif

src/parsers/csv.c

@@ -88,3 +88,17 @@ Mat *csv_get_mat(CSV *csv, int *cols, size_t c_size) {
 
     return new_mat;
 }
+
+Mat *csv_get_mat_slice(CSV *csv, Slice slice) {
+    size_t n_cols = slice.upper - slice.lower;
+    Mat *new_mat = mat_create(csv->values->rows, n_cols);
+
+    size_t new_mat_col = 0;
+    for (size_t i = 0; i < n_cols; i++) {
+        for (size_t r = 0; r < csv->values->rows; r++) {
+            mat_set(new_mat, r, new_mat_col, mat_get(csv->values, r, slice.lower + i));
+        }
+        new_mat_col++;
+    }
+    return new_mat;
+}