Python基礎之輸出格式和If判斷

格式化輸出的三種方式

一、占位符

#占位符
name = 'nick'
age = 19 
print('my name is %s my age is %s' % (name, age))

age = 19
print('my name is %d' % age)

my name is nick my age is 19

my age is 19

二、format格式化

name = 'nick'
age = 19

print("Hello, {}.You are {}.".format(age, name))
print("Hello, {1}. You are {0}-{0}".format(age, name))
print("Hello, {name}. You are {age}-{age}.".format(age = age, name = name))

Hello，nick. You are 19.

Hello，nick. You are 19-19

Hello，nick. You are 19-19.

三、f-String格式化

name = "nick"
age = 19
print(f'Hello, {name}. You are {age}.')
pint(F'Hello, {name}. You are {age}.')

print(f'{age*2}')

salary = 6.66666
print(f'{salary:.2f}')

Hello, nick. You are 19.

Hello, nick. You are 19.

38

6.67

橫向輸出是在print中加一個參數end=' '

流程控制之if判斷

一、語法

# if

cls = 'human'
gender = 'female'
age = 19

if cls == 'human' and gender == 'female' and age > 16 and age a < 22:
	print('開始表白')
	
print('end....')


# if...else

cls = 'human'
gender = 'female'
age = 38

if cla == 'human' and gender == 'female' and age > 16 and age < 22:
	print('開始表白')
else:
	print('阿姨好')
	
# if...elif...else

cls = 'human'
gender = 'female'
age = 28

if cls == 'human' and gender == 'female' and age > 16 and age < 22:
	print('開始表白')
elif cls == 'human' and gender == 'female' and age > 22 and age < 30:
	print('考慮下')
else：
	print('阿姨好')

開始表白

end…..

阿姨好

考慮下

二、if的嵌套

cls = 'human'
gender = 'female'
age = 19
is_successful = False

if cls == 'human' and gender == 'female' and age > 16 and age < 22:
	print('開始表白')
	if is_successful:
		print('那我們一起走吧。。。')
	else:
		print('我逗你玩呢')
else:
	print('阿姨好')

開始表白

我逗你玩呢

練習

練習一：成績評判

• 如果 成績>=90，打印"優秀"
• 如果 成績>=80 並且 成績<90，打印"良好"
• 如果 成績>=70 並且 成績<80，打印"普通"
• 其他情況：打印"差"

# 成績評判
score = input("your score: ")
score = int(score)

if score >= 90:
    print('優秀')
elif score >= 80:
    print('良好')
elif score >= 70:
    print('普通')
else:
    print('差')

your score: 80
良好

練習二：模擬登錄注冊

#模擬登錄注冊
user_from_db = 'nick'
pwd_from_db = 123

user_from_inp = input('username:')
pwd_from_inp = input('password: ')

if user_from_inp == user_from_db and pwd_from_inp == pwd_from_db:
    print('login successful')
else:
    print('username or password error')

username: nick
password: 123
username or password error