What are the flow control statements in python?

Python's flow control statements include: 1. if statement, which executes different code blocks according to conditions; 2. for loop, used to traverse a sequence or other iterable objects; 3. while loop, when given When the condition is true, a section of code is repeatedly executed; 4. The break statement is used to terminate the current loop and jump out of the entire loop; 5. The continue statement is used to skip the remaining statements of the current loop; 6. The pass statement represents a no-op; 7. The if-elif-else statement executes different code blocks based on multiple conditions.

Operating system for this tutorial: Windows 10 system, Python version 3.11.4, Dell G3 computer.

Python's flow control statements mainly include the following types:

if statement: is used to execute different code blocks based on conditions. For example:

x = 10  
if x > 5:  
    print("x is greater than 5")

for loop: is used to traverse a sequence (such as a list or tuple) or other iterable object and execute a piece of code on each element in turn. For example:

for i in range(5):  
    print(i)

while loop: Repeatedly execute a section of code when a given condition is true. For example:

i = 0  
while i < 5:  
    print(i)  
    i += 1

break statement: is used to terminate the current loop and jump out of the entire loop. For example:

for i in range(5):  
    if i == 3:  
        break  
    print(i)

continue statement: is used to skip the remaining statements of the current loop and then continue with the next round of loops. For example:

for i in range(5):  
    if i == 3:  
        continue  
    print(i)

pass statement: is used to indicate a no-op operation, which has no effect when it is executed. For example:

for i in range(5):  
    pass

if-elif-else statement: is used to execute different code blocks based on multiple conditions. For example:

x = 10  
if x > 10:  
    print("x is greater than 10")  
elif x == 10:  
    print("x is equal to 10")  
else:  
    print("x is less than 10")

In addition to the process control statements mentioned above, Python also has some other process control tools, including:

List Comprehensions: This is a concise way to create a list in one line of code, applying a loop and conditional statement at the same time. For example:

squares = [x**2 for x in range(10) if x % 2 == 0]

Generator Expressions: Generator expressions are very similar to list comprehensions, but they do not create a new list. Instead, they return a generator object that can be used to generate data on demand. For example:

squares = (x**2 for x in range(10) if x % 2 == 0)

map() function and filter() function: These two functions can be used to apply a function to each element of a sequence or to filter a sequence. For example:

# 使用map()函数将列表中的每个元素平方  
squared_list = map(lambda x: x**2, range(10))  
  
# 使用filter()函数过滤出列表中的偶数元素  
even_list = filter(lambda x: x % 2 == 0, range(10))

sorted() function: This function can be used to sort a sequence. For example:

numbers = [5, 2, 9, 1, 5, 6]  
sorted_numbers = sorted(numbers)

Exception handling: Python also supports exception handling, using try/except statements to capture and handle possible errors. For example:

try:  
    # 尝试执行一些可能会引发异常的代码  
    x = 1 / 0  
except ZeroDivisionError:  
    # 当出现ZeroDivisionError异常时执行这里的代码  
    print("Cannot divide by zero!")

These flow control tools and statements make Python a flexible and powerful programming language that can be used to solve various types of problems.

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