python - 在执行操作时转置此表的最快方法

Question

我有这个：

name phenotype
ID1      tall
ID2      tall
ID3     short
ID4      tall

我要这个：

ID1  ID2  ID3  ID4 phenotype
yes  yes   no  yes      tall
no   no  yes   no     short

我试过这种方法：

df = pd.DataFrame({'name' : ['ID1', 'ID2', 'ID3', 'ID4'], 'phenotype' : ['tall', 'tall', 'short', 'tall']})

sample_dict = {}
for sample in df['name']:
    var_list = []
    for variant in df['phenotype'].unique():
        sample_subset = df[df['name'] == sample]
        if variant in sample_subset['phenotype'].to_list():
            var_list.append('yes')
        else:
            var_list.append('no')

        sample_dict[sample] = var_list
sample_dict['phenotype'] = ['tall', 'short']
sample_df = pd.DataFrame(sample_dict)

在执行我描述的操作时，是否有更好更快的转置该表的方法？

标签： pythonpandas

Answer 1

尝试pd.crosstab：

print(
    pd.crosstab(df["phenotype"], df["name"])
    .replace({0: "no", 1: "yes"})
    .reset_index()
    .rename_axis("", axis=1)
)

印刷：

  phenotype  ID1  ID2  ID3  ID4
0     short   no   no  yes   no
1      tall  yes  yes   no  yes