为什么切片后我得到了Empty DataFrame？
archive = self.get_rate_archive(settings.CURRENCIES_RATE_SOURCE)
rate_source = archive.open(options["rate_filename"])
rate_df = pd.read_csv(rate_source)
print(rate_df)
Date USD JPY BGN CYP CZK DKK EEK GBP HUF ... INR KRW MXN MYR NZD PHP SGD THB ZAR Unnamed: 42
0 2020-03-20 1.0707 118.37 1.9558 NaN 27.191 7.4691 NaN 0.91028 350.91 ... 80.4650 1335.64 25.6864 4.7052 1.8521 54.895 1.5515 34.851 18.5127 NaN
1 2020-03-19 1.0801 118.63 1.9558 NaN 27.606 7.4731 NaN 0.92985 356.06 ... 81.1400 1364.14 26.2955 4.7686 1.8903 55.593 1.5643 35.076 18.6800 NaN
2 2020-03-18 1.0934 117.78 1.9558 NaN 27.154 7.4732 NaN 0.92190 351.38 ... 81.1355 1377.80 26.2014 4.7793 1.8727 56.441 1.5760 35.448 18.5624 NaN
3 2020-03-17 1.0982 117.50 1.9558 NaN 26.985 7.4732 NaN 0.90823 347.04 ... 81.5670 1365.21 25.0491 4.7777 1.8420 56.563 1.5691 35.461 18.2288 NaN
4 2020-03-16 1.1157 117.76 1.9558 NaN 26.960 7.4731 NaN 0.90918 344.97 ... 82.8075 1373.34 25.4478 4.8092 1.8499 57.625 1.5868 35.937 18.5602 NaN
... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ...
5427 1999-01-08 1.1659 130.09 NaN 0.58187 34.938 7.4433 15.6466 0.70940 250.15 ... NaN 1366.73 NaN NaN 2.1557 NaN 1.9537 NaN 6.7855 NaN
5428 1999-01-07 1.1632 129.43 NaN 0.58187 34.886 7.4431 15.6466 0.70585 250.09 ... NaN 1337.16 NaN NaN 2.1531 NaN 1.9436 NaN 6.8283 NaN
5429 1999-01-06 1.1743 131.42 NaN 0.58200 34.850 7.4452 15.6466 0.70760 250.67 ... NaN 1359.54 NaN NaN 2.1890 NaN 1.9699 NaN 6.7307 NaN
5430 1999-01-05 1.1790 130.96 NaN 0.58230 34.917 7.4495 15.6466 0.71220 250.80 ... NaN 1373.01 NaN NaN 2.2011 NaN 1.9655 NaN 6.7975 NaN
5431 1999-01-04 1.1789 133.73 NaN 0.58231 35.107 7.4501 15.6466 0.71110 251.48 ... NaN 1398.59 NaN NaN 2.2229 NaN 1.9554 NaN 6.9358 NaN
[5432 rows x 43 columns]
dates = rate_df["Date"].tolist()
for date in dates:
rate_df = rate_df.loc[rate_df.Date == date]
print(rate_df)
...
Empty DataFrame
Columns: [Date, USD, JPY, BGN, CYP, CZK, DKK, EEK, GBP, HUF, LTL, LVL, MTL, PLN, ROL, RON, SEK, SIT, SKK, CHF, ISK, NOK, HRK, RUB, TRL, TRY, AUD, BRL, CAD, CNY, HKD, IDR, ILS, INR, KRW, MXN, MYR, NZD, PHP, SGD, THB, ZAR, Unnamed: 42]
Index: []
...
我从csv文件本身获取日期。为什么我的日期框是空的？
我认为您应该尝试像这样对数据帧进行切片：
dates = rate_df["Date"].tolist()
for date in dates:
rate_byDate = rate_df.copy()
rate_byDate = rate_df[rate_df.Date == date]
print(rate_byDate)
我认为你应该使用这种方法，因为否则在第一个循环之后，你的数据框将被第一个日期覆盖，然后在第二个循环中，你的数字框将不再包含其他日期。
如果这有帮助，请告诉我！
感谢@EnriqueBet的提示。
它起作用：
archive = self.get_rate_archive(settings.CURRENCIES_RATE_SOURCE)
rate_source = archive.open(options["rate_filename"])
rate_df = pd.read_csv(rate_source)
dates = rate_df["Date"].tolist()
for date_from_list in dates:
df = rate_df.copy()
df = rate_df[df.Date == date_from_list]