python - 我怎么能在recarray中做过滤器

Question

我有一个名为 data.csv 的数据文件

name,value
A,10
1,20
B,30
3,20
...

所以问题是我使用 numpy 和 mlab 来加载这个 csvfile

data = mlab.csv2rec(data.csv) 

我有一个问题，我怎样才能过滤掉data.name is a number？

例如：输出应该是

1,20
3,20

Answer 1

If you want to filter the recarray while preserving the structure of the filtered records:

filter_idx = [i for i, s in enumerate(data.names) if s.isdigit()]
data[filter_idx]

gives

rec.array([('1', 20), ('3', 20)], 
      dtype=[('names', 'S1'), ('value', '<i4')])

---

If you just want to print out the filtered records like in your example output I would just do it and catch the exceptions:

for rec in data:
    try:
        print int(rec.names), rec.value
    except:
        pass

prints

1 20
3 20

Answer 2

您可以使用isinstance()。

for i in data:
    if isinstance(data.name, int):
        print data.name, data.value

或者

new_data = list(x for x in data if isinstance(x.name, int))

在这个例子中工作正常：

data = [[1,10], ["a", 20], [2, 30], ["b", 40], [3, 50]]
new_data = list(x for x in data if isinstance(x[0], int))
print new_data