Python For Loops and Loop Control Statements

For Loops

• Used to iterate over a sequence (such as a list, tuple, or string) and execute a block of code for each item
• Syntax: for variable in iterable:
• Example: fruits = ['apple', 'banana', 'cherry']; for fruit in fruits: print(fruit)

Loop Control Statements

• break: exits the loop prematurely
  • Example: for i in range(5): if i == 3: break; print(i)
• continue: skips the current iteration and moves to the next one
  • Example: for i in range(5): if i == 3: continue; print(i)
• pass: does nothing, used as a placeholder when a statement is required syntactically
  • Example: for i in range(5): if i == 3: pass; print(i)

Nested Loops

• A loop inside another loop
• Used to iterate over multiple sequences or perform complex iterations
• Example:

for i in range(3):
    for j in range(3):
        print(f"i: {i}, j: {j}")

Iterating Over Data Structures

• Lists: for item in list:
• Tuples: for item in tuple:
• Strings: for char in string:
• Dictionaries:
  • for key in dict: iterates over keys
  • for value in dict.values(): iterates over values
  • for key, value in dict.items(): iterates over key-value pairs
• Sets: for item in set:

For Loops

• Used to iterate over sequences like lists, tuples, or strings, executing a block of code for each item
• Syntax is for variable in iterable:

Loop Control Statements

Break Statement

• Exits the loop prematurely
• Example: use break to stop a loop when a condition is met (e.g., for i in range(5): if i == 3: break; print(i))

Continue Statement

• Skips the current iteration and moves to the next one
• Example: use continue to skip an iteration when a condition is met (e.g., for i in range(5): if i == 3: continue; print(i))

Pass Statement

• Does nothing and is used as a placeholder when a statement is required syntactically
• Example: use pass when a statement is needed, but no action is required (e.g., for i in range(5): if i == 3: pass; print(i))

Nested Loops

• A loop inside another loop
• Used to iterate over multiple sequences or perform complex iterations
• Example: iterating over multiple ranges (e.g., for i in range(3): for j in range(3): print(f"i: {i}, j: {j}"))

Iterating Over Data Structures

Lists

• Iterate over list items using for item in list:

Tuples

• Iterate over tuple items using for item in tuple:

Strings

• Iterate over characters in a string using for char in string:

Dictionaries

• Iterate over dictionary keys using for key in dict:
• Iterate over dictionary values using for value in dict.values():
• Iterate over key-value pairs using for key, value in dict.items():

Sets

• Iterate over set items using for item in set: