Python数据分析学习——循环语句

1.字符隐藏getpass,不能在pycharm运行：

import getpass
username=input('username:')
password=getpass.getpass('password:')

2.if else条件判断+while else循环+count控制：

age_of_oldboy=56
count=0
while count<3:
    if count==3:
        break
    guess_age=int(input('guess age:'))
    if guess_age==age_of_oldboy:
        print('yes,you got it.')
        break
    elif guess_age>age_of_oldboy:
        print('think smaller!')
    else:
        print('think bigger!')
    count+=1
else:
    print('You have tried too many times.')

注：可在count+=1后面加入if判断根据用户输入内容决定是否继续循环，如果是则对count赋值0，否则退出。

3.for else循环：替代while

age_of_oldboy=56
count=0
for i in range(3):
    guess_age=int(input('guess age:'))
    if guess_age==age_of_oldboy:
        print('yes,you got it.')
        break
    elif guess_age>age_of_oldboy:
        print('think smaller!')
    else:
        print('think bigger!')
else:
    print('You have tried too many times.')

4.continue：提前结束本循环重新开始

for i in range(0,10):
    if i<3:
        print('loop:',i)
    else:
        continue
    print('hehe...')

5.循环嵌套:外层循环10次，内层循环5次

 for i in range(10):
    print('--',i)
    for j in range(10):
        print(j)
        if j>3:
            break

6.input用户交互：利用%或format简化

编写代码：

name = input('name:')
age = input('age:')
job = input('job:')
salary = input('salary:')
info = '''
-----info of name''' + name + '''-----
Name:''' + name + '''
Age:''' + age + '''
Job:''' + job + '''
Salary:''' + salary
print(info)

输出结果：

name:alice
age:24
job:pe
salary:12000

-----info of alice-----
Name:alice
Age:24
Job:pe
Salary:12000

(1)利用%s、%d(相当于int)简化info部分：

info1 = '''
-----info of %s-----
Name:%s
Age:%d
Job:%s
Salary:%s
''' % (name, name, age, job, salary)

(2)利用format简化info部分：

info2 = '''
-----info of {_name}-----
Name:{_name}
Age:{_age}
Job:{_job}
Salary:{_salary}
'''.format(_name=name,
           _age=age,
           _job=job,
           _salary=salary)

注：也可以用list的[0]、[1]、[3]等代替{}内容。