13_loop_control_statements.py

#======================================================================================
#                           LOOP CONTROL FLOW STATEMENTS
#--------------------------------------------------------------------------------------
# Python provides 3 main loop control flow statements:
# 1) break      --> stop the loop
# 2) continue   --> skip the current iteration
# 3) pass       --> do nothing(placeholder)
#=====================================================================================
#--------------------------------------------------------------------------------------
# 1) break-->control flow by stopping loop
#--------------------------------------------------------------------------------------
for i in range(1,11):
    if i == 6:
        break
    print(i)

names = ["charlie", "john", "maria", " ", "emma", "Raja"]
for name in names:
    if name == " ":
        print("Empty name detected")
        break
    print(f"Name = {name}")

#--------------------------------------------------------------------------------------
# 2) continue-->control flow by skipping iteration
#--------------------------------------------------------------------------------------
for i in range(1,11):
    if i == 6:
        continue
    print(i)

names = ["charlie", "john", "maria", " ", "emma", "Raja"]
for name in names:
    if name == " ":
        print("Empty name detected")
        continue
    print(f"Name = {name}")

#--------------------------------------------------------------------------------------
# 3) pass-->control  flow placeholder(do nothing)
#--------------------------------------------------------------------------------------
for i in range(1,11):
    if i == 6:
       pass
    print(i)

names = ["charlie", "john", "maria", " ", "emma", "Raja"]
for name in names:
    if name == " ":
        #print("Empty name detected")
        pass
    print(f"Name = {name}")

# Real world use cases
# loop through a list of days and print only the working days,
# skip the weekends
days = ["Sun","Mon", "Tue", "Wed", "Thu", "Fri", "Sat"]
for day in days:
    if day in ["Sun", "Sat"]:
        continue
    print(f"Workday:{day}")

#scan emails to block unsafe data from entering your system
emails = [
    "shaikmunna@gmail.com",
    "abdulla@gmail.com",
    "DROP TABLE USERS;",
    "rasheed@outlook.in",
    "john@gmail.com"
]

for email in emails:
    if ";" in email:
        print("SQL injection: Hacker attack")
        print("Email Processing is Stopped")
        break
    print(f"processing email: {email}")