Question

我目前正在努力处理一个小块，它应该筛选一个大文件并只写出满足某个功能限制的特定数据。我主要是格式化问题：

from __future__ import print_function
import numpy as np

log = open("out_test", "w")
log1 = open("out_test_empty", "w")

def function(kx,ky,ek,sz,ef,tol):
    lines = []
    if ((ef-tol)<ek<(ef+tol)):
        lines.append((kx,ky,sz))
#       (lines.append((kx,ky,sz)) if (kx,ky,sz) is not None else None)
    return lines


arr = []
with open('test10') as my_file:
    for line in my_file:
        ##numbers_float=map(float, line.split())
        arr.append(map(float, line.split()))
        print(function(arr[-1][0],arr[-1][1],arr[-1][2],arr[-1][3],-0.5462,0.001), file = log)
#       print(', '.join(str(d) for d in function(arr[-1][0],arr[-1][1],arr[-1][2],arr[-1][3],-0.5462,0.001)), file = log)
#       str_list = (', '.join(str(d) for d in function(arr[-1][0],arr[-1][1],arr[-1][2],arr[-1][3],-0.7,0.001)))
#       str_list = filter(None, str_list)
#       print(str_list, file =log)

#print(arr[:][:])

#import fileinput
#for line in fileinput.FileInput("test",inplace=1):
#    if line.rstrip():
#        print(line, file=log1)

测试数据文件（大约10 ^ 7行）：

  0.11361097E+01  0.19677992E+01 -0.54626220E+00 -0.87053581E+00
  0.11361097E+01  0.19677992E+01 -0.54626220E+00  0.87053581E+00
  0.11361097E+01  0.19677992E+01  0.22336976E+01  0.90485914E+00
  0.11361097E+01  0.19677992E+01  0.22336976E+01 -0.90485916E+00
  0.11361097E+01  0.19677992E+01  0.23120941E+01 -0.42934308E+00
  0.11361097E+01  0.19677992E+01  0.23120941E+01  0.42934308E+00
  0.11361097E+01  0.19677992E+01  0.24740033E+01 -0.98827766E+00
  0.11361097E+01  0.19677992E+01  0.24740033E+01  0.98827766E+00
  0.11361097E+01  0.19677992E+01  0.24777489E+01 -0.52602145E+00
  0.11361097E+01  0.19677992E+01  0.24777489E+01  0.52602145E+00

我想要的文件输出是：

1.1361097 1.9677992 -0.87053581
1.1361097 1.9677992  0.87053581

现在我正在接受：

[(1.1361097, 1.9677992, -0.87053581)]
[(1.1361097, 1.9677992, 0.87053581)]
[]
[]
[]
[]
[]
[]
[]
[]

所以我的问题是：

如何摆脱追加的空列表 - ＆gt; []？
如何摆脱括号和括号？

我知道这些问题经常被问到，我试图解决它，但我无法解决它。在评论的部分，你会看到我已经尝试过的......

Answer 1

您的函数返回元组列表：

def function(kx,ky,ek,sz,ef,tol):
    lines = []
    if ((ef-tol)<ek<(ef+tol)):
        lines.append(  (kx,ky,sz)  )   # emphasis: this appends a tuple to the list
    return lines

以(kx,ky,sz)为元组。只需将数字作为浮动列表返回：

def function(kx,ky,ek,sz,ef,tol):
    if ((ef-tol)<ek<(ef+tol)):
        return [kx,ky,sz]
    # implicitly return None if your condition is not met

如果您想将它们打印为不是列表而是打印为单个值，请在打印前分解function(...)返回的列表：

# error when decomposing None - you would have to return [] instead of None implicitly
print(* function(arr[-1][0],arr[-1][1],arr[-1][2],arr[-1][3],-0.5462,0.001), file = log)

你会得到新的/错误，所以也许最好将部分写入你的其他文件：

   newVals = function(arr[-1][0],arr[-1][1],arr[-1][2],arr[-1][3],-0.5462,0.001)
   if newVals: # meaning: if the function returns something, print its elements
       print(*newVals, file = log)

很好阅读how to debug small programs (#2) - 可以在该链接中找到 - python非常“打印出友好”，有时您只需要保留更多变量来打印它们并查看结果如何建造。

如何避免附加空列表＆amp;括号和括号

1 个答案: