Question

我有1000个元素的numpy数组，我想将其转换为字符串。我试过了

    map(str,a)

非常慢。还有其他选择吗？

由于

Answer 1

如果要将numpy数组写入文本文件，请使用numpy.savetxt。根据您的评论，这就是您想要的。

但是，为了回答你的原始问题，如果你可以使用固定长度的字符串，有更快的方法将numpy数组转换为字符串。

对于简单的事情，您可以将其转换为固定长度的字符串数组。

E.g。

import numpy as np

# Generate some random floating-point data
x = np.random.random(100)

# Convert it to fixed-length strings with a maximum length of 5 characters
y = x.astype('|S5')

print 'Original Array'
print x
print 'Converted to fixed-length strings'
print y

输出：

Original Array
[ 0.25669986  0.55193955  0.39582629  0.40559555  0.75836284  0.13031881
  0.84448005  0.20825593  0.32131777  0.5738351   0.72200185  0.14700912
  0.62306299  0.21549908  0.96927738  0.13327512  0.06948689  0.34436446
  0.58785565  0.58557563  0.3229981   0.0356056   0.67621536  0.07334146
  0.25804432  0.59477881  0.10382583  0.47255438  0.0747982   0.41586059
  0.54310507  0.68426668  0.14454108  0.62950246  0.30748958  0.56605352
  0.25072476  0.70945076  0.72311872  0.2357644   0.59668047  0.27536644
  0.96557189  0.97749755  0.95629738  0.15902741  0.32879056  0.60324024
  0.07463531  0.77562818  0.20181969  0.53088481  0.85723283  0.25163771
  0.06770161  0.45302361  0.3500556   0.37980214  0.87567327  0.94278158
  0.28586752  0.35682239  0.8746877   0.99562283  0.38323688  0.90561641
  0.64439454  0.53465359  0.37486244  0.33196021  0.99762377  0.29295412
  0.50162051  0.17312773  0.80100872  0.04233855  0.69062118  0.59194923
  0.65409137  0.25636784  0.40616824  0.82858658  0.90618301  0.87036914
  0.37534268  0.566982    0.55454063  0.75048023  0.56582157  0.62779239
  0.05196828  0.86418784  0.9862007   0.43015164  0.43576519  0.64918536
  0.99522735  0.81158283  0.02115479  0.47745413]
Converted to fixed-length strings
['0.256' '0.551' '0.395' '0.405' '0.758' '0.130' '0.844' '0.208' '0.321'
 '0.573' '0.722' '0.147' '0.623' '0.215' '0.969' '0.133' '0.069' '0.344'
 '0.587' '0.585' '0.322' '0.035' '0.676' '0.073' '0.258' '0.594' '0.103'
 '0.472' '0.074' '0.415' '0.543' '0.684' '0.144' '0.629' '0.307' '0.566'
 '0.250' '0.709' '0.723' '0.235' '0.596' '0.275' '0.965' '0.977' '0.956'
 '0.159' '0.328' '0.603' '0.074' '0.775' '0.201' '0.530' '0.857' '0.251'
 '0.067' '0.453' '0.350' '0.379' '0.875' '0.942' '0.285' '0.356' '0.874'
 '0.995' '0.383' '0.905' '0.644' '0.534' '0.374' '0.331' '0.997' '0.292'
 '0.501' '0.173' '0.801' '0.042' '0.690' '0.591' '0.654' '0.256' '0.406'
 '0.828' '0.906' '0.870' '0.375' '0.566' '0.554' '0.750' '0.565' '0.627'
 '0.051' '0.864' '0.986' '0.430' '0.435' '0.649' '0.995' '0.811' '0.021'
 '0.477']

这会快得多，但你只限于固定长度的字符串。（显然，你可以改变长度。只需使用x.astype('|S10')或任何你想要的长度。）

但是，如果您只是想将数据写入文件，请使用savetxt。

有效地为字符串转换长numpy数组

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