Question

我正在尝试绘制直方图，但我一直收到这个错误;

Traceback (most recent call last):
File "<pyshell#62>", line 1, in <module>
plt.hist(a)
File "/usr/lib/pymodules/python2.7/matplotlib/pyplot.py", line 2827, in hist
stacked=stacked, **kwargs)
File "/usr/lib/pymodules/python2.7/matplotlib/axes.py", line 8312, in hist
xmin = min(xmin, xi.min())
File "/usr/lib/python2.7/dist-packages/numpy/core/_methods.py", line 21, in _amin
out=out, keepdims=keepdims)
TypeError: cannot perform reduce with flexible type

我对python很新，我想做的就是这个;

import numpy, matplotlib.pyplot

line = " "
a = []
b = []
c = []
alpha = []
beta = []
gama = []

while x.readline():
    line = x.readline()
    a.append(line[16:23])
    b.append(line[25:32])
    c.append(line[27:34])
    alpha.append(line[40:47])
    beta.append(line[49:54])
    gama.append(line[56:63])

pyplot.hist(a)'

当我运行这段代码时，我遇到了这个错误。我哪里做错了？我真的很感激帮助

Answer 1

看起来你试图根据字符串而不是数字来绘制直方图。尝试这样的事情：

from matplotlib import pyplot
import random
# generate a series of numbers
a = [random.randint(1, 10) for _ in xrange(100)]
# generate a series of strings that look like numbers
b = [str(n) for n in a]

# try to create histograms of the data
pyplot.hist(a) # it produces a histogram (approximately flat, as expected)

pyplot.hist(b) # produces the error as you reported.

通常，最好使用预先编写的库来读取外部文件中的数据（例如，请参阅numpy's genfromtxt或csv module）。但至少，您可能需要将读入的数据视为数字，因为readline返回字符串。例如：

for line in f.read():
    fields = line.strip().split()
    nums = [int(field) for field in fields]

现在nums为您提供该行的整数列表。

错误：无法使用灵活类型执行缩减

1 个答案: