修炼基本功:条件与循环

截图


代码

#!/usr/bin/env python
# coding: utf-8

# In[3]:


x = -2
if x<0:
    y = -x
else:
    y = x
print(y)


# In[6]:


id = 2
if id == 0:
    print('Red')
elif id == 1:
    print('Yello')
else:
    print('Green')


# In[9]:


l = [1, 2, 3, 4]
for item in l:
    print(item)


# In[15]:


d = {'name': 'jason', 'dob': '2000-01-01', 'gender': 'male'}
for k in d:
    print(k)
    
print('----------')

for v in d.values():
    print(v)

print('----------')

for k, v in d.items():
    print('key: {}, value: {}'.format(k, v))


# In[19]:


l = [1, 2, 3, 4, 5, 6, 7]
for index in range(0, len(l)):
    if index < 5:
        print(l[index])


# In[50]:


# 在 for 循环中,如果需要同时访问索引和元素,你可以使用 enumerate() 函数来简化代码
l = [11, 22, 33, 44, 55, 66, 77]
for index, items in enumerate(l):
    if index < 5:
        print(items)


# In[25]:


l = [1, 2, 3, 4]
index = 0
while index < len(l):
    print(l[index])
    index += 1


# In[26]:


expression1 if condition else expression2 for item in iterable
for item in iterable:
    if condition:
        expression1
    else:
        expression2


# In[28]:


expression for item in iterable if condition
for item in iterable:
    if condition:
        expression


# In[34]:


x = [2.3, 2.5, 3.5, 4.0]
y = [2*item + 5 if item > 0 else -2*item+5 for item in x]


# In[38]:


text = ' Today, is, Sunday'
text_list = [s.strip() for s in text.split(',') if len(s.strip()) > 4]
print(text_list)


# In[51]:


xx = [11, 22, 33]
yy = [22, 33, 44]
a = [(x, y) for x in xx for y in yy if x != y]
print (a)


# In[52]:


# 给定下面两个列表 attributes 和 values,要求针对 values 中每一组子列表 value,输出其和 attributes 中的键对应后的字典,最后返回字典组成的列表。

attributes = ['name', 'dob', 'gender']
values = [['jason', '2000-01-01', 'male'], 
['mike', '1999-01-01', 'male'],
['nancy', '2001-02-01', 'female']
]

# expected output:
[{'name': 'jason', 'dob': '2000-01-01', 'gender': 'male'}, 
{'name': 'mike', 'dob': '1999-01-01', 'gender': 'male'}, 
{'name': 'nancy', 'dob': '2001-02-01', 'gender': 'female'}]


# In[57]:


attributes = ['name', 'dob', 'gender']
values = [['jason', '2000-01-01', 'male'], 
['mike', '1999-01-01', 'male'],
['nancy', '2001-02-01', 'female']
]

y = [dict(zip(attributes,v)) for v in values]
print (y)

print('-------------------------------')

lis = []
for i in values:
    dic = {}
    for n, j in enumerate(i):
        dic[attributes[n]] = j
    lis.append(dic)
print(lis)

print('-------------------------------')

lis = []
for i in values:
    print(i)
    print(dict(zip(attributes, i)))
    print(lis.append(dict(zip(attributes, i))))
    
print(lis)

Jupyter Notebook Code File

_修炼基本功:条件与循环.ipynb

文章名: 《 修炼基本功:条件与循环》

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最后修改:2019 年 11 月 03 日 10 : 31 AM

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