Python入门基础知识学习（二）

course = 'Python for Beginners'
print(len(course))

course = 'Python for Beginners'
course.upper()
course.lower()
course.title()
course.find()
course.replace(,)

print(course.upper())

print(course.lower())

course = 'Python for Beginners'
print(course.find('P'))
# 字符串中第一个大写P的索引是0，则返回0
print(course.find('o'))
print(course.find('O'))
# 在这个字符串中没有大写字母O，则返回-1
print(course.find('Beginners'))
# 返回指定字符串的首字符在该字符串中的索引，字符串中第一个大写B的索引是11，则返回11

course = 'Python for Beginners'
print(course.replace('Beginners','Absolute Beginners'))
# find和replace方法都是区分大小写的
print(course.replace('beginners','Absolute Beginners'))
# replace方法如果在字符串中没有找到该字符串，不做任何改变
print(course.replace('P','J'))
# 替换单个字符

course = 'Python for Beginners'
print('Python' in course)
# 检查字符串中是否存在`python`字符串，
print('python' in course)
# in操作符在使用时区分大小写，'python'在当前字符串中不存在，所以返回False

print(10 + 3)

print(10 - 3)

print(10 * 3)

print(9 / 3)

print(9 // 3)

print(10 % 3)

print(10 ** 3)

x = 10
x = x + 3
print(x)

x = 10
x += 3
print(x)
x -= 3
print(x)
x *= 3
print(x)
x /= 3
print(x)
x //= 3
print(x)

parenthesis    eg:()
exponentiation    eg:2**3
multiplication or division    eg:2*3 or 2/3
addition or subtraction    eg:2+3 or 2-3

x = 10 + 3 * 2
print(x)
x = 10 + 3 * 2 ** 2
print(x)
x = (10 + 3) * 2 ** 2
print(x)

x = (2 + 3) * 10 - 2
print(x)

x = 2.9
print(round(x))
# 返回3

x = -2.9
print(abs(x))
# 返回2.9

import math
print(math.ceil(2.9))
print(math.floor(2.9))