数据类型

Number

INFO

• Integer：整数（负、零和正）示例:-1,0,1
• float：示例:-3.15,-2.21,-1.01,0.0,1.1,2.3
• Complex：示例:1 + j,2 + 4j

String

表示文本

• "Hello, World!"

Boolean

INFO

• True
• False

List

有序的可变序列

• [0, 1, 2, 3, 4, 5]
• ['Banana', 'Orange', 'Mango', 'Avocado']
• ['Banana', 10, False, 9.81]

Tuple

有序的不可变序列

• ('he', 'Pawel', 'Brook', 'Abraham', 'Lidiya')
• ('Earth', 'Jupiter', 'Neptune', 'Mars', 'Venus', 'Saturn', 'Uranus', 'Mercury')

Dictionary

无序的键值对集合

{
  'first_name': 'he',
  'last_name': 'fang',
  'country': 'China', 
  'age': 100, 
  'is_married': False,
  'skills': ['JS', 'Vue', 'Node', 'Python']
}

Set

无序的不重复元素集合

• {2, 4, 3, 5}
• {3.14, 9.81, 2.7}

检查数据类型

# Checking data types
print(type(10))                  # Int
print(type(3.14))                # Float
print(type(1 + 3j))              # Complex number
print(type('he'))                # String
print(type(True))                # Boolean
print(type([1, 2, 3]))           # List
print(type({'name':'fang'}))     # Dictionary
print(type((9.8, 3.14, 2.7)))    # Tuple
print(type({9.8, 3.14, 2.7}))    # Set

强制转换

# int to float
num_int = 10
print('num_int',num_int)         # 10
num_float = float(num_int)
print('num_float:', num_float)   # 10.0

# float to int
gravity = 9.81
print(int(gravity))             # 9

# int to str
num_int = 10
print(num_int)                  # 10  <class 'int'>
num_str = str(num_int)
print(num_str)                  # 10  <class 'str'>

# str to int or float
num_str = '10.6'
print('num_float', float(num_str))  # 10.6
print('num_int', int(num_str))      # 10 ValueError:invalid literal for int() with base 10: '10.6'

# str to list
first_name = 'he'
print(first_name)               # 'he'
first_name_to_list = list(first_name)
print(first_name_to_list)            # ['h','e']