Python 写入 txt 报错

Question

我试图在 while 循环中将不同的东西写入文本文件，但它只写入一次。我想写点东西到unmigrated.txt

import urllib.request
import json
Txtfile = input("Name of the TXT file: ")
fw = open(Txtfile + ".txt", "r")
red = fw.read()
blue = red.split("\n")
i=0
while i<len(blue):
    try:
        url = "https://api.mojang.com/users/profiles/minecraft/" + blue[i]
        rawdata = urllib.request.urlopen(url)
        newrawdata = rawdata.read()
        jsondata = json.loads(newrawdata.decode('utf-8'))
        results = jsondata['id']
        url_uuid = "https://sessionserver.mojang.com/session/minecraft/profile/" + results
        rawdata_uuid = urllib.request.urlopen(url_uuid)
        newrawdata_uuid = rawdata_uuid.read()
        jsondata_uuid = json.loads(newrawdata_uuid.decode('utf-8'))
        try:
            results = jsondata_uuid['legacy']
            print (blue[i] + " is " + "Unmigrated")
            wf = open("unmigrated.txt", "w")
            wring = wf.write(blue[i] + " is " + "Unmigrated\n")
        except:
            print(blue[i] + " is " + "Migrated")
    except:
        print(blue[i] + " is " + "Not-Premium")

    i+=1

Answer 1

您在循环内用 w 不断覆盖打开文件，因此您只能看到写入文件的最后数据，要么在循环外打开文件一次，要么用 a 打开 追加。打开一次是最简单的方法，您也可以使用 range 而不是 while 或更好地再次遍历列表:

with open("unmigrated.txt", "w") as f: # with close your file automatically
     for ele in blue:
          .....

同时 wring = wf.write(blue[i] + "is "+ "Unmigrated\n") 将 wring 设置为 None这是 write 返回的内容，因此可能没有任何实际用途。

最后，使用空白 expect 通常不是一个好主意，捕获您期望的特定异常并记录或至少在您遇到错误时打印。

使用 requests图书馆，我会打破你的代码做这样的事情:

import requests


def get_json(url):
    try:
        rawdata = requests.get(url)
        return rawdata.json()
    except requests.exceptions.RequestException as e:
        print(e)
    except ValueError as e:
        print(e)
    return {}

txt_file = input("Name of the TXT file: ")

with open(txt_file + ".txt") as fw, open("unmigrated.txt", "w") as f:  # with close your file automatically
    for line in map(str.rstrip, fw): # remove newlines
        url = "https://api.mojang.com/users/profiles/minecraft/{}".format(line)
        results = get_json(url).get("id")
        if not results: 
            continue
        url_uuid = "https://sessionserver.mojang.com/session/minecraft/profile/{}".format(results)
        results = get_json(url_uuid).get('legacy')
        print("{} is Unmigrated".format(line))
        f.write("{} is Unmigrated\n".format(line))

我不确定 'legacy' 在代码中的位置，我将把那个逻辑留给你。您还可以直接遍历文件对象，这样您就可以忘记将行拆分为 blue。