無法將變量/字典寫入文本文件 - python

Question

我正在嘗試記錄一些數據，但是無論我做什么，我似乎都無法將變量寫入文件......我可以獲得一個標准字符串來寫入，但不是變量。

# in my  actualy implementation toLog is meant to copy another nested dictionary but python only refrences it 
toLog = NestedDictionary
# toLog = {'bought': {nestedDict}, 'sold':{nestedDict}}
# this line will work however the original data will not although it prints to console
#toLog = {'bought': {1:1, 2:2, 3:3, 4:4}, 'sold':{1:1, 2:2, 3:3, 4:4}}
file = open(filename, 'w')
file.write("trades:\nbought:")
for price, amount in toLog['bought'].items(): 
    print(f"sanity check: {price} : {amount}")
    file.write(str(price) + " : " +  str(amount) + "\n")
toLog = {'bought': {}, 'sold':{}}

這會產生一個文件

trades:
bought:

但不再有，值/變量打印到控制台，但我無法讓它們寫入文件

我也試過

# in my  actualy implementation toLog is meant to copy another nested dictionary but python only refrences it 
toLog = NestedDictionary
# toLog = {'bought': {nestedDict}, 'sold':{nestedDict}}
# this line will work however the original data will not although it prints to console
toLog = {'bought': {1:1, 2:2, 3:3, 4:4}, 'sold':{1:1, 2:2, 3:3, 4:4}}
with open(filename, 'w') as file:
    print('trades:\nbought:', file=file) 
    for price, amount in toLog['bought'].items():
        print(f"sanity check: {price} : {amount}")
        print(f"{price} : {amount}", file=file)
toLog = {'bought': {}, 'sold':{}}

產生相同的結果。

Answer 1

給你兩個選擇。 第一個是純文本，第二個是 json。 我沒有在 json 中添加“交易：”，但您可以將其添加為第一個 dict 鍵，它會在那里。

import json

fn = "test_output.txt"
fn2 = "test_output.json"

toLog = {'bought': {1:1, 2:2, 3:3, 4:4}, 'sold':{1:1, 2:2, 3:3, 4:4}}


output_txt = "trades:"

for log_key, log_vals in toLog.items():
    output_txt += f"\n{log_key}:"
    for nested_key, nested_val in log_vals.items():
        output_txt += f"\n{nested_key}:{nested_val}"

# Gives you the text output like you described above
with open (fn, 'w') as f:
    f.write(output_txt)

# Gives you a json output which is common for dict data
with open (fn2, 'w') as f2:
    f2.write(json.dumps(toLog, indent=4))

Answer 2

最初我的代碼不包含導致此問題的錯誤，它已被編輯以包含它。

我的問題是我正在清理字典。 最初我認為在寫入文件后在最后執行清除操作是安全的，但似乎情況並非如此，即使它將正確的值打印到控制台，我也不知道為什么。

但是，如果其他人遇到此問題，解決方案似乎是創建需要copy庫的深層副本。

import copy

toLog = copy.deepcopy(stuffToLog)
with open(filename, 'w') as file:
    print('trades:\nbought:', file=file) 
    for price, amount in toLog['bought'].items():
        print(f"sanity check: {price} : {amount}")
        print(f"{price} : {amount}", file=file)
toLog = {'bought': {}, 'sold':{}}