根据数据帧的值在需要的地方插入其他行

你可以用 pd.concat 使用生成器表达式:

df = pd.read_csv('file.csv')  # read file into dataframe

gen = (pd.DataFrame({'num': np.arange(row.num_from, row.num_to+1),
                     'var1': row.var1, 'var2': row.var2}) \
       for row in df.itertuples(index=False))

res = pd.concat(gen, ignore_index=True)

print(res)

   num  var1  var2
0    1    20    30
1    2    40    50
2    3    40    50
3    4    40    50
4    5    40    50
5    6    60    70
6    7    60    70
7    8    80    90

使用:

#generate values between
v = [np.arange(a,b+1) for a, b in df[['num_from', 'num_to']].values]
#get lengths of arrays
lens = [len(x) for x in v]

from itertools import chain

df = pd.DataFrame({
    #flatten arrays 
    'num' : list(chain.from_iterable(v)), 
    #repeat columns
    'var1' : df['var1'].values.repeat(lens),
    'var2' : df['var2'].values.repeat(lens)
})

print (df)
   num  var1  var2
0    1    20    30
1    2    40    50
2    3    40    50
3    4    40    50
4    5    40    50
5    6    60    70
6    7    60    70
7    8    80    90