問題描述

有沒有辦法在 Python 中使用變量中的字符串調用方法？ (Is there a way to call a method in Python using a string inside a variable?)

我是編碼新手，所以如果這個問題已經在其他地方得到回答，請原諒我，但我試著找了一會兒卻找不到答案。

為了澄清我正在嘗試的問題為了解決，我將用下面的代碼說明它：

#Sample problem
ABCD = []
KEY = "ABCD"
data = 123
[str(KEY)].append(data)

print(f"{ABCD}")

這裡我試圖調用列表 ABCD 的 append 方法，但變量 KEY 包含字符串“ABCD”。此代碼不起作用，但說明了我的問題。我想知道是否可以使用變量而不是硬編碼來調用上述方法，例如：

if KEY == "ABCD":
    ABCD.append(data)

print(f"{ABCD}")

謝謝！！

參考解法

方法 1:

I think I shall share my method not using eval. It accesses all the local variables currently in the script. The program uses this to it's advantage allowing it to locate whether a variable exists or not. Another thing used in this program are dictionaries which help us store our information neatly. Though it might be a tad bit overcomplicated Testcase 1 #ABCD does exist

ABCD = []

KEY = "ABDC"

data = 123

import sys, pprint

sys.displayhook = pprint.pprint

variables = locals()

check if KEY can be found in locals
if variables.get(KEY) != None:
#create a dict ,KEY = key, "[]" is value
#{'ABCD': []}
varDict = {KEY:variables.get(KEY)}
#append data
varDict[KEY].append(data)
print(varDict)

KEY is not variable in locals
else:

    print('could not find')

</code></pre>
expected output
{'ABCD': [123]}

Testcase 2 #ABCD is not existant, instead ABDC.
ABCD = []
KEY = "ABDC"
data = 123
import sys, pprint
sys.displayhook = pprint.pprint
variables = locals()
#check if KEY can be found in locals
if variables.get(KEY) != None:
    #create a dict ,KEY = key, "[]" is value
    #{'ABCD': []}
    varDict = {KEY:variables.get(KEY)}
    #append data
    varDict[KEY].append(data)
    print(varDict)
#KEY is not variable in locals
else:
    print('could not find')

expected output
could not find

Let me know if a test case does not work.
(by Gee、Thavas Antonio)
參考文件


Is there a way to call a method in Python using a string inside a variable? (CC BY‑SA 2.5/3.0/4.0)