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从文件中加载列表

文件格式示例

1 2 3
4 5 6

list_device_group = []
def load_list_from_file(filepath):
    with open(filepath,'rU') as f:
        for line in f:
            separator=' '
            item = "-".join(line.strip().decode('utf-8').split(separator)[0:3])
            list_device_group.append(item)
        return list_device_group

从文件中加载json

#!/usr/bin/env python
# -*- coding:utf-8 -*-
import re
import string
import json
import sys
reload(sys)
sys.setdefaultencoding('utf8')
f = open("/tmp/test.file")
data = json.load(f).encode('UTF-8')
print data[0]['admin_name']

请求api，返回json

convert to json data 1

def json_loads(ip):
    url = 'http://192.168.5.19/api/v1/getVmarehost?private_ip_address=172.17.100.21' %ip
    res=requests.get(url)
    json_data=res.json()
    #mrtgs = json_data.get("data")[0].get("mrtgs")[0]
    return json_data

convert to json data 2

# do not verify ssl
context = ssl._create_unverified_context()
def json_loads(url):
    response = urllib2.urlopen(url, context=context)
    html=response.read()
    data = json.loads(html)
    return data

convert to json data using urllib2

def json_loads(url):
    response = urllib2.urlopen(url)
    html=response.read()
    data = json.loads(html)
    return data

列表循环

for i,v in enumerate(info_list):

for i,v in enumerate(info_list):
    if '导演:' in v:
        print info_list[i+1]
    elif '主演:' in v:
        print info_list[i+1]
    elif '片国家/地区:' in v:
        print info_list[i+1]
    elif '语言:' in v:
        print info_list[i+1]
    elif 'IMDb链接:' in  v:
        print info_list[i+1]

循环字典同时修改数据

modifying-a-python-dict-while-iterating-over-it

user_mgt_system_v2_dict_and_file.py

# you cannot iterate while modifying the dict
# 1, use list(RESULT) to force a copy of keys to be made
# 2, use deep copy, RESULT.copy()

1, for m in list(RESULT):
2, RESULT.copy()

for k, v in RESULT_DICT.items():
    #for m in list(RESULT):
    for m in RESULT.copy():
        if k == m:
            continue
        else:
            RESULT[k] = v

解决 csv 写入中文乱码

如果将包含中文的结果输出到csv文件，一般默认使用Excel打开文件时，文件内容会出现乱码，而使用文本编辑器打开不会乱码。这是因为Excel默认的编码方式为‘GBK‘，而文本编辑器默认的格式为‘utf-8'。

使用codecs包在创建文件后添加语句f.write(codecs.BOM_UTF8)可解

  • python 2.7
import csv
import codecs
f = file('test.csv', 'wb')
# excel打开内容不乱码的核心语句
f.write(codecs.BOM_UTF8)
writer = csv.writer(f)
writer.writerow(['姓名', '年龄', '电话'])
  • python 3.x
with open(filename, 'a', newline='', encoding='utf-8-sig') as f: # 中文需要设置成utf-8格式
f_csv = csv.writer(f)
    f_csv.writerow(('城市', '日期', '天气', '风力', '温度', '摄氏度')) # 头部信息
    f_csv.writerows(data)

write the list to result file

def write_to_file(file, *info_list):
    with open(file, 'w')  as f:
        f.writelines(str(line) + "\n" for line in info_list)

insert fisrt line

def line_prepender(filename, line):
    with open(filename, 'r+') as f:
        content = f.read()
        f.seek(0, 0)
        f.write(line.rstrip('\r\n') + '\n' + content)

head_instruction = "subject_id\ttype\t中文名\t年份\t片长\t评分\t评价人数\t国家\t语言\t类型\t主演\t导演\tIMDB编号" line_prepender('test.txt', head_instruction)

TypeError: string indices must be integers

data 为返回数据。

  • 1， 需要使用data=json.loads(data) //将字符串转成json格式，或 data=eval(data) //将字符串转成dict格式。
In [38]: s = {'userBasicInfoId': 7714931}                                                     

In [39]: data = json.dumps(s)                                                                 

In [40]: data['userBasicInfoId']                                                              
---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
<ipython-input-40-1a8a364a2793> in <module>
----> 1 data['userBasicInfoId']

TypeError: string indices must be integers

2， data为字符串，非字典类型，即使使用json.loads() 转换后也不行，此时需要使用 try 作异常判断。

In [29]: core_data = 'user with umsUserId=9993006 and userType=125 not found.'                

In [30]: core_data['billingCode']                                                             
---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
<ipython-input-30-4b8cc8c94bac> in <module>
----> 1 core_data['billingCode']

TypeError: string indices must be integers

列表求交集或共同元素

1，求两个

method 1

def get_common_data(l1, l2):
    common_list = []
    for i in l1:
        if len(list(filter(lambda x: x == i, l2))) > 0:
            common_list.append(i)
    return common_list

method 2

[ i for i in a if i in b ]

2，求多个

def get_common_data_multi(l1, *info_list): 
    for l in info_list: 
        common_list = [] 
        for i in l:
            if len(list(filter(lambda x: x == i, l1))) > 0:
                common_list.append(i) 
        l1 = common_list
    return common_list
    
或（https://www.zhihu.com/question/37422498）
In [1]: L = [[1,2,3,4], [2,3,4,5], [3,4,5,6],[1,2,3,4,5,6]]

In [2]: set(L[0]).intersection(*L[1:])
Out[2]: {3, 4}