numpy.delete改变花车阵列串 [英] numpy.delete changing arrays of floats to strings

问题描述

我使用了 numpy.delete 函数删除多个数组元素。我从这个问题开始做这个简单的/如果块更Python 抵达，将给予那里的答案，这个后：

I'm using the numpy.delete function to remove elements from several arrays. I started from this question Make this simple for/if block more pythonic and arrived, after applying the answer given there, to this:

# Data lists.
a = [3,4,5,12,6,8,78,5,6]
b = [6,4,1.,2,8,784.,43,6.,2]
c = [8,4.,32.,6,1,7,2.,9,23]

# Maximum limit.
max_limit = 20.

# Store indexes of elements to be removed.
indexes = [i for i, t in enumerate(zip(b, c)) if any(e > max_limit for e in t)]

# Remove elements from all lists.
big_array = np.array([a, b, c])
clean_array = np.delete(big_array, indexes, axis=1)

# Final clean lists.
a_clean, b_clean, c_clean = clean_array

我遇到的问题是，我的列表中的一个实际上由的字符串的而不是花车，像这样的：

The issue I'm having is that one of my lists is actually made of strings rather than floats, like this:

# Data lists.
a = ['a','b','c','d','e','f','g','h','i'] # <-- strings
b = [6,4,1.,2,8,784.,43,6.,2] # <-- floats
c = [8,4.,32.,6,1,7,2.,9,23] # <-- floats

当我将code中的 numpy.delete 线以上转换中的所有的最终名单的（<$ C $的所有元素C> a_clean，b_clean，c_clean ）以字符串，而不是preserving只有第一个字符串，其余为浮动。

and when I apply the code above the numpy.delete line converts all elements in all final lists (a_clean, b_clean, c_clean) to strings rather than preserving only the first one as strings and the rest as floats.

如何prevent这种情况的发生或修复它，如果它不能得到帮助？

How can I prevent this from happening or fix it if it can't be helped?

推荐答案

如果您要使用numpy的，你会好起来的转换您的列表，以数组。它看起来是这样的：

If you are going to use numpy, you are going to be better off converting your lists to arrays. It would look something like:

a = np.array(a)
b = np.array(b)
c = np.array(c)

mask = (b > max_limit) | (c > max_limit)

a = a[mask]
b = b[mask]
c = c[mask]

>>> a
array(['c', 'f', 'g', 'i'],
      dtype='|S1')
>>> b
array([   1.,  784.,   43.,    2.])
>>> c
array([ 32.,   7.,   2.,  23.])

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