Update L3_4_Conditionals_and_Loops.md

basic_prog_for_bioinfo/L3_4_Conditionals_and_Loops.md

@@ -8,20 +8,42 @@
 
 3. **Comparison operators** such as `==` (equal), `!=` (not equal), `<` (less than), `>` (greater than), `<=` (less than or equal to), and `>=` (greater than or equal to) are often used in the boolean conditions. 
 
+  * Python
+
     ```python
     if x == y:
         print("x and y are equal")
     ```
 
+  * R
+
+    ```R
+    if (x == y) {
+        print("x and y are equal")
+    }
+    ```
+
 4. **Logical operators** such as `and`, `or`, and `not` in Python, and `&`, `|`, and `!` in R, can be used to combine or invert boolean conditions.
 
+  * Python
+
     ```python
     if x > 0 and y > 0:
         print("Both x and y are positive numbers")
     ```
+
+  * R
+
+    ```R
+    if (x > 0 & y > 0) {
+        print("Both x and y are positive numbers")
+    }
+    ```    
 
-5. **Membership operators** such as `in` keyword in Python and the `%in%` operator in R check for membership or containment within a collection such as a list, tuple, or array. In Python, `in` is not limited to collections, it can also be used to check for substrings within a string. On the other hand, in R, we have to use `grepl` to check for substrings.
+6. **Membership operators** such as `in` keyword in Python and the `%in%` operator in R check for membership or containment within a collection such as a list, tuple, or array. In Python, `in` is not limited to collections, it can also be used to check for substrings within a string. On the other hand, in R, we have to use `grepl` to check for substrings.
 
+  * Python
+
     ```python
     # Check if an element exists in a list
     fruits = ["apple", "banana", "cherry"]
@@ -36,6 +58,8 @@
         print("Substring found.")
     ```
 
+  * R
+
     ```r
     fruits <- c("apple", "banana", "cherry")
     if ("banana" %in% fruits) {
@@ -50,6 +74,25 @@
     }
     ```
 
+  * Bash
+
+    ```bash
+    fruits=("apple" "banana" "cherry")
+
+    contains() {
+      local n=$#
+      local value=${!n}
+      for ((i=1;i < $#;i++)) {
+        if [ "${!i}" == "${value}" ]; then
+          echo "Yes, '${value}' is in the fruits array."
+          return 0
+        fi
+      }
+      return 1
+    }
+
+    contains "${fruits[@]}" "banana"
+    ```
 7. Conditional statements can be *nested*, meaning you can have `if-else` statements within `if-else` statements to check for further conditions.
 
 **Loops:**
@@ -118,6 +161,24 @@
    # Output: 0, 1, 2, 3, 4, 6, 7, 8, 9
    ```
 
+  * Bash
+    
+    ```bash
+    for i in {0..9}
+    do
+       echo $i
+    done
+    ```
+
+    ```bash
+    i=0
+    while [ $i -lt 10 ]
+    do
+       echo $i
+       ((i++))  # Increment i
+    done
+    ```
+
 8. Loops can also be *nested*, meaning you can have loops within loops. This is useful when working with multi-dimensional data structures like matrices or nested lists.
 
 Remember that understanding the concepts of conditionals and loops is foundational to learning how to program, and they are used in almost every piece of code, especially in bioinformatics where dealing with large amounts of data is common.