1
我想根據公式將列添加到數據框。我不認爲我目前的解決方案是pythonic /高效的。所以我正在尋找更快的選擇。在熊貓數據框中使用公式的高效方法
我有3列
import pandas as pd
df = pd.DataFrame([
[1,1,20.0],
[1,2,50.0],
[1,3,30.0],
[2,1,30.0],
[2,2,40.0],
[2,3,30.0],
],
columns=['seg', 'reach', 'len']
)
# print df
df
seg reach len
0 1 1 20.0
1 1 2 50.0
2 1 3 30.0
3 2 1 30.0
4 2 2 40.0
5 2 3 30.0
# Formula here
for index, row in df.iterrows():
if row['reach'] ==1:
df.ix[index,'cumseglen'] = row['len'] * 0.5
else:
df.ix[index,'cumseglen'] = df.ix[index-1,'cumseglen'] + 0.5 *(df.ix[index-1,'len'] + row['len'])
#print final results
df
seg reach len cumseglen
0 1 1 20.0 10.0
1 1 2 50.0 45.0
2 1 3 30.0 85.0
3 2 1 30.0 15.0
4 2 2 40.0 50.0
5 2 3 30.0 85.0
的表如何改善式步驟的效率?
謝謝!這就說得通了。 – Prashanth