Python基础

for i in range(1,10,2): #2.步长
	print(i)
	print(i**2) #平方

import numpy as np
for k in np.arange(0,1,0.1):
    print(k)

aList = [1,5,6,8,12,54,66]
for item in aList:
    print(item)
print('continue')

t = [1,2,3,4,5,6,7,8,9,10]
for i in range(4,8):
    print(t[i] ** 2)
print('---------------')
for k in t[4:8]:
    print(t[k]*2)

d = { 'Name':'lili', 'Age': 18}
for i,j in d.items():
    print(i,j)
print('---------------')
# 输出key
for i in d.keys():
    print(i)
print('---------------')
# 输出value
for i in d.values():
    print(i)

x = 8
y = 3
z = 8

if x == y:
    print('x is equal to y')
elif x > y:
    print('x is bigger than y')
else:
    print('x is not equal to y')

for i in range(1,10):
    if i % 2 == 0:
        print("%d is even" %i)
    elif i % 3 == 0:
        print("%d is multiple of 3" %i)
    else:
        print("%d is odd" % i)

total = 0
while total < 10:
    total += 1
print("sum = %d" %total)

a = 1
while a < 6:
    if a < 3:
        print(a)
    elif(a == 3):
        print('a==3')
    else:
        print('python')
    a += 1

a = 1
while a:
    print(a)
    a += 1
    if a == 5:
        break
a

a = 1
while a<7:
    a+=1
    if a == 3:
        continue
    print(a)

m = [i ** 2 for i in range(5)]
m

m = []
for i in range(5):
    m.append(i**2)
m

a = ['a','b','c']
b = [1,2,3]

c = zip(a,b)
print(type(c))
print(list(zip(a,b)))
print(dict(zip(a,b)))

def f(x):
    return x * x
f(66)

m = [1,2,3,4,5]
results = [f(x) for x in m]
print(results)

import math

for i in [1,2,3,-4,-5,6,7,8,'python3']:
    try:
        print("%d 的开根号值是 %f" %(i, math.sqrt(i)))
    except ValueError:
        print("无法计算 %d的开根号值" %i)
    except TypeError:
        print("输入 %s的类型不对，它不是一个数字" %i)
    else:
        print("计算成功")
    finally:
        print("进行下一次计算")

def prime_choice(a): 
    pass              #啥也不干

prime_choice('a')

def prime_choice(a):
    if type(a) != int:
        raise TypeError("输入类型错误")
    print("输入类型正确")

prime_choice(10)
prime_choice("python3")

def prime_choice(a):
    if isinstance(a,int):
        print("输入类型正确")
    else:
        raise TypeError("输入类型错误")

#prime_choice('python')
prime_choice(10)

def prime_choice(a):
    if isinstance(a,int) == False:
        raise TypeError("输入类型错误")
    for i in range(2,a):
        if a % i == 0:
            print("它不是质数，它可以被%d整除" %i)
        if i == a - 1:
            print("%d是质数" %a)


prime_choice(7)

字典操作

1. 创建字典

dictionary = {'a':1 , 'b':2, 'c':3}

2. 字典中获取值1

# 用key从字典中获取值
dictionary['a']                        
输出 1

3. 字典中获取值2

   • 根据键使用字典'get'方法获取字典中相应值。若key不存在，返回第二个参数对应的值。

# 用key从字典中获取值
dictionary.get('d', 100)               # 用key从字典中获取值                      
输出 100

4. 字典中删除某映射

   • 使用'del'删除映射。

del dictionary['a']                    # 删除映射
dictionary                             # 查看删除映射后的字典                      
输出 {'b': 2, 'c': 3}

5. 新增一个键值

dictionary["name"] = '17哥'
dictionary                     
输出 {'b': 2, 'c': 3, 'name': '17哥'}