[英]When converting a pandas dataframe to csv, how can i seperate the headers of the dataframe into different columns of the csv-file?
[英]How can I specify a different decimal format on each column when using Pandas DataFrame to CSV?
我正在解析文本文件中的特定列,其數據如下所示:
n Elapsed time TimeUTC HeightMSL GpsHeightMSL P Temp RH Dewp Dir Speed Ecomp Ncomp Lat Lon
s hh:mm:ss m m hPa ∞C % ∞C ∞ m/s m/s m/s ∞ ∞
1 0 23:15:43 198 198 978.5 33.70 47 20.87 168.0 7.7 -1.6 7.6 32.835222 -97.297940
2 1 23:15:44 202 201 978.1 33.03 48 20.62 162.8 7.3 -2.2 7.0 32.835428 -97.298000
3 2 23:15:45 206 206 977.6 32.89 48 20.58 160.8 7.5 -2.4 7.0 32.835560 -97.298077
4 3 23:15:46 211 211 977.1 32.81 49 20.58 160.3 7.8 -2.6 7.4 32.835660 -97.298160
5 4 23:15:47 217 217 976.5 32.74 49 20.51 160.5 8.3 -2.7 7.8 32.835751 -97.298242
6 5 23:15:48 223 223 975.8 32.66 48 20.43 160.9 8.7 -2.8 8.2 32.835850 -97.298317
我對第一個 m/s 列執行一次計算(將 m/s 轉換為 kt)並將 hpa > 99.9 的所有數據寫入輸出文件。 該輸出如下所示:
978.5,198,33.7,20.87,168.0,14.967568
978.1,201,33.03,20.62,162.8,14.190032
977.6,206,32.89,20.58,160.8,14.5788
977.1,211,32.81,20.58,160.3,15.161952
976.5,217,32.74,20.51,160.5,16.133872
975.8,223,32.66,20.43,160.9,16.911407999999998
代碼執行良好,輸出文件適用於我使用它的目的,但是有沒有辦法將列輸出格式化為特定的小數位? 正如您在我的代碼中看到的那樣,我嘗試了 df.round 但它不會影響輸出。 我還查看了 float_format 參數,但這似乎會將格式應用於所有列。 我的預期輸出應如下所示:
978.5, 198, 33.7, 20.9, 168, 15
978.1, 201, 33.0, 20.6, 163, 14
977.6, 206, 32.9, 20.6, 161, 15
977.1, 211, 32.8, 20.6, 160, 15
976.5, 217, 32.7, 20.5, 161, 16
975.8, 223, 32.7, 20.4, 161, 17
我的代碼如下:
import pandas as pd
headers = ['n', 's', 'time', 'm1', 'm2', 'hpa', 't', 'rh', 'td', 'dir', 'spd', 'u', 'v', 'lat', 'lon']
df = pd.read_csv ('edt_20220520_2315.txt', encoding_errors = 'ignore', skiprows = 2, sep = '\s+', names = headers)
df['spdkt'] = df['spd'] * 1.94384
df['hpa'].round(decimals = 1)
df['spdkt'].round(decimals = 0)
df['t'].round(decimals = 1)
df['td'].round(decimals = 1)
df['dir'].round(decimals = 0)
extract = ['hpa', 'm2', 't', 'td', 'dir', 'spdkt']
with open('test_output.txt' , 'w') as fh:
df_to_write = df[df['hpa'] > 99.9]
df_to_write.to_csv(fh, header = None, index = None, columns = extract, sep = ',')
您可以傳遞字典,然后如果將列按0
舍入為整數:
d = {'hpa':1, 'spdkt':0, 't':1, 'td':1, 'dir':0}
df = df.round(d).astype({k:'int' for k, v in d.items() if v == 0})
print (df)
n s time m1 m2 hpa t rh td dir spd u v \
0 1 0 23:15:43 198 198 978.5 33.7 47 20.9 168 7.7 -1.6 7.6
1 2 1 23:15:44 202 201 978.1 33.0 48 20.6 163 7.3 -2.2 7.0
2 3 2 23:15:45 206 206 977.6 32.9 48 20.6 161 7.5 -2.4 7.0
3 4 3 23:15:46 211 211 977.1 32.8 49 20.6 160 7.8 -2.6 7.4
4 5 4 23:15:47 217 217 976.5 32.7 49 20.5 160 8.3 -2.7 7.8
5 6 5 23:15:48 223 223 975.8 32.7 48 20.4 161 8.7 -2.8 8.2
lat lon spdkt
0 32.835222 -97.297940 15
1 32.835428 -97.298000 14
2 32.835560 -97.298077 15
3 32.835660 -97.298160 15
4 32.835751 -97.298242 16
5 32.835850 -97.298317 17
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