python - 填充 DataFrame Pandas Python

Question

我有一个类似的数据集，即使代码给了我正确的输出；我不想使用三个 for 循环。有没有办法以更好的方式做到这一点？

import pandas as pd

col = ["a","b","c","d"]
index = ["0","1","2","3"]
dict_ = {("0","a"):8,
         ("1","a"):3,
         ("3","b"):2}

df = pd.DataFrame(columns=col,index=index)
for i in range(len(dict_)):
    for j in range(len(df)):
        for k in range(len(df)):
            if (str(df.index[j]),str(df.columns[k])) == dict_.keys()[i]:
                df.at[df.index[j],df.columns[k]] = dict_.values()[i]

print df

标签： pythonpandasperformancedataframefor-loop

Answer 1

IIUC，使用reindex

pd.Series(dict_).unstack().reindex(index=index,columns=col)
Out[245]: 
     a    b   c   d
0  8.0  NaN NaN NaN
1  3.0  NaN NaN NaN
2  NaN  NaN NaN NaN
3  NaN  2.0 NaN NaN