In this course, we will take a closer look at one of the important control structures in Python, the The Here, “variable” will receive one element of the sequence in each iteration, and “code to execute” contains the actual tasks to perform.<\/p>\n\n\n\n Let’s take a look at the most basic example of iterating over a list.<\/p>\n\n\n\n This code will print each fruit name from the The Let’s understand this with an example:<\/p>\n\n\n\n Output:<\/p>\n\n\n\n A nested This code will print all the numbers in the 2D list.<\/p>\n\n\n\n Surprisingly, in Python, the In this case, ‘Banana found!’ will be printed, demonstrating how the The Output:<\/p>\n\n\n\n If you want to stop the Output:<\/p>\n\n\n\n When using multiple loops, performance should be considered. Especially with large datasets, nested loops can adversely affect performance. Here are some tips to minimize this:<\/p>\n\n\n\nfor<\/code> loop. The for<\/code> loop is primarily used to iterate over a specific range of values. In Python, the for<\/code> loop is useful for traversing sequences (lists, tuples, strings, etc.) and helps to efficiently handle repetitive tasks.<\/p>\n\n\n\n1. Basic Structure of for Loop<\/h2>\n\n\n\n
for<\/code> loop in Python is designed to repeatedly execute a specific block of code for each element in a sequence. The basic structure is as follows:<\/p>\n\n\n\nfor variable in sequence:\n code to execute\n <\/code><\/pre>\n\n\n\n2. Example: Iterating Over a List<\/h2>\n\n\n\n
fruits = ['apple', 'banana', 'cherry']\nfor fruit in fruits:\n print(fruit)\n <\/code><\/pre>\n\n\n\nfruits<\/code> list. The output will be as follows:<\/p>\n\n\n\napple\nbanana\ncherry\n <\/code><\/pre>\n\n\n\n3. Using for Loop with range() Function<\/h2>\n\n\n\n
range()<\/code> function is mainly used with the for<\/code> loop to repeat code a specified number of times. It has the syntax range(start, stop[, step])<\/code>, and the parameters are as follows:<\/p>\n\n\n\n\n
start<\/code>: The number where the count begins. The default is 0.<\/li>\n\n\n\nstop<\/code>: The number where the count ends (not included).<\/li>\n\n\n\nstep<\/code>: The interval between counts. The default is 1.<\/li>\n<\/ul>\n\n\n\nfor i in range(3):\n print(i)\n <\/code><\/pre>\n\n\n\n0\n1\n2\n <\/code><\/pre>\n\n\n\n4. Nested for Loops<\/h2>\n\n\n\n
for<\/code> loop simply means having another for<\/code> loop inside a for<\/code> loop. Here is an example of a nested for<\/code> loop that iterates over a two-dimensional list:<\/p>\n\n\n\nmatrix = [[1, 2, 3], [4, 5, 6], [7, 8, 9]]\nfor row in matrix:\n for num in row:\n print(num)\n <\/code><\/pre>\n\n\n\n5. for Loop and else<\/h2>\n\n\n\n
for<\/code> loop can be used with else<\/code>. You can write code in the else<\/code> block that will execute when the for<\/code> loop has completed normally. Let’s see the following example:<\/p>\n\n\n\nfor fruit in fruits:\n if fruit == 'banana':\n print('Banana found!')\n break\nelse:\n print('No bananas.')\n <\/code><\/pre>\n\n\n\nfor-else<\/code> construct works.<\/p>\n\n\n\n6. Using with enumerate()<\/h2>\n\n\n\n
enumerate()<\/code> function helps to deal with both index and elements simultaneously when iterating through a sequence. Let\u2019s take a closer look with the following example:<\/p>\n\n\n\nfor index, fruit in enumerate(fruits):\n print(index, fruit)\n <\/code><\/pre>\n\n\n\n0 apple\n1 banana\n2 cherry\n <\/code><\/pre>\n\n\n\n7. Using Break to Avoid Infinite Loops<\/h2>\n\n\n\n
for<\/code> loop under certain conditions, you can use the break<\/code> statement. This helps avoid infinite loops or unnecessary iterations.<\/p>\n\n\n\nfor i in range(10):\n if i == 5:\n break\n print(i)\n <\/code><\/pre>\n\n\n\n0\n1\n2\n3\n4\n <\/code><\/pre>\n\n\n\n8. Performance Considerations<\/h2>\n\n\n\n