python-day06_01 break_pass_continue的使用

# ### 关键字的使用  pass break continue
# pass 过 (代码块中的占位符)
"""
if 20 == 20:
    pass
    
while True:
    pass
"""

# break 终止当前循环 (只能用在循环之中)
# 1 ~ 10 遇到5终止循环
i = 1
while i <= 10:
    print(i)
    if i == 5:
        break
    i +=1
    
    
i = 1
while i <= 3:
    
    j = 1
    while j <=3:
        if j == 2:
            break
        print(i,j)
        j+=1

    i +=1
# 1 1
# 2 1 
# 3 1
"""
if 5 == 5: error
    break
"""

# continue 跳过当前循环,从下一次循环开始
# 打印 1 ~ 10 跳过5
i = 1
while i <= 10:    
    if i == 5:
        # 在跳过之前,因为会终止执行后面的代码,从下一次循环开始
        # 为了避免死循环,手动加1
        i += 1
        continue
    print(i)
    i +=1
    
# 1 ~ 100 打印所有不含有4的数字
# 方法一
print("<============>")
i = 1
while i <= 100:
    strvar = str(i)
    # print(strvar)
    if "4" in strvar:
        i += 1
        continue
    print(i)
    i +=1
    
# 方法二
print("<============>")
i = 1
while i <= 100:
    if i // 10 == 4 or i % 10 == 4:
        i+=1
        continue
    print(i)
    i+=1