从文本文件python3检索字典/列表

Question

I want to save a column of values from "coins_info.txt" into a list variable into my program. Here are the contents of "coins_info.txt":

Name,ICO,Max,USD_ROI
Bitcoin,0.0,19535.7,N/A
Ethereum,0.0,1389.18,N/A
Ripple,0.0,3.6491,N/A
Bitcoin Cash,0.0,4091.7,N/A
EOS,0.99,21.4637,2068.05%
Litecoin,0.0,366.153,N/A
...

I want to get the ICO from every single coin in "coins_info.txt" and save it into a list that looks like this:

icos = [0.0, 0.0, 0.0, 0.0, 0.99, 0.0, ...]

I tried this code:

import pandas as pd

df = pd.read_csv("coins_info.txt")
icos = df["ICO"].values.tolist()

But I got this error for line 4 of my code:

Traceback (most recent call last):
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/pandas/core/indexes/base.py", line 2442, in get_loc
    return self._engine.get_loc(key)
  File "pandas/_libs/index.pyx", line 132, in pandas._libs.index.IndexEngine.get_loc (pandas/_libs/index.c:5280)
  File "pandas/_libs/index.pyx", line 154, in pandas._libs.index.IndexEngine.get_loc (pandas/_libs/index.c:5126)
  File "pandas/_libs/hashtable_class_helper.pxi", line 1210, in pandas._libs.hashtable.PyObjectHashTable.get_item (pandas/_libs/hashtable.c:20523)
  File "pandas/_libs/hashtable_class_helper.pxi", line 1218, in pandas._libs.hashtable.PyObjectHashTable.get_item (pandas/_libs/hashtable.c:20477)
KeyError: 'ICO'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "temp.py", line 280, in <module>
    init_max_prices("btc.txt", "init")
  File "temp.py", line 212, in init_max_prices
    icos = df["ICO"].values.tolist()
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/pandas/core/frame.py", line 1964, in __getitem__
    return self._getitem_column(key)
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/pandas/core/frame.py", line 1971, in _getitem_column
    return self._get_item_cache(key)
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/pandas/core/generic.py", line 1645, in _get_item_cache
    values = self._data.get(item)
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/pandas/core/internals.py", line 3590, in get
    loc = self.items.get_loc(item)
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/pandas/core/indexes/base.py", line 2444, in get_loc
    return self._engine.get_loc(self._maybe_cast_indexer(key))
  File "pandas/_libs/index.pyx", line 132, in pandas._libs.index.IndexEngine.get_loc (pandas/_libs/index.c:5280)
  File "pandas/_libs/index.pyx", line 154, in pandas._libs.index.IndexEngine.get_loc (pandas/_libs/index.c:5126)
  File "pandas/_libs/hashtable_class_helper.pxi", line 1210, in pandas._libs.hashtable.PyObjectHashTable.get_item (pandas/_libs/hashtable.c:20523)
  File "pandas/_libs/hashtable_class_helper.pxi", line 1218, in pandas._libs.hashtable.PyObjectHashTable.get_item (pandas/_libs/hashtable.c:20477)
KeyError: 'ICO'

What can I do to fix my code?

Answer 1

You can load the txt file in pandas and convert the ICO column to list, Here is the complete code:

import pandas as pd
df = pd.read_csv('coins_info.txt', sep=",", header=0)
icos =list(df['ICO']) 
or 
icos = df['ICO'].values.tolist()

Output:

icos = [0.0, 0.0, 0.0, 0.0, 0.99, 0.0]

Answer 2

Your code working nice with your sample data:

df = pd.read_csv("coins_info.txt")
print (df)
           Name   ICO         Max   USD_ROI
0       Bitcoin  0.00  19535.7000       NaN
1      Ethereum  0.00   1389.1800       NaN
2        Ripple  0.00      3.6491       NaN
3  Bitcoin Cash  0.00   4091.7000       NaN
4           EOS  0.99     21.4637  2068.05%
5      Litecoin  0.00    366.1530       NaN

icos = df["ICO"].values.tolist()
print (icos)
[0.0, 0.0, 0.0, 0.0, 0.99, 0.0]

so problem is something else.

---

KeyError: 'ICO'

means there is no column ICO .

First check columns names if some whitespaces or similar:

print (df.columns.tolist())

Then need:

df.columns = df.columns.str.strip()

Or another possible problem is different separator as default sep=',' .

Then need:

df = pd.read_csv("coins_info.txt", sep=';')
icos = df["ICO"].values.tolist()

Answer 3

I want to get the ICO from every single coin in "coins_info.txt" and save it into a list that looks like this...

For this task in isolation, Pandas may be overkill. You can use the built-in csv module to read your column into a list:

import csv
from io import StringIO

mystr = StringIO("""Name,ICO,Max,USD_ROI
Bitcoin,0.0,19535.7,N/A
Ethereum,0.0,1389.18,N/A
Ripple,0.0,3.6491,N/A
Bitcoin Cash,0.0,4091.7,N/A
EOS,0.99,21.4637,2068.05%
Litecoin,0.0,366.153,N/A""")

# replace mystr with open('coins_info.txt', 'r')
with mystr as fin:
    reader = csv.DictReader(fin)
    ico_list = [float(row['ICO']) for row in reader]

print(ico_list)

[0.0, 0.0, 0.0, 0.0, 0.99, 0.0]