如何在python中使用"-“？

Question

所以这段python代码是给我的。这暗示着它起作用了，但很明显我有问题。我想知道有没有人能告诉我出了什么问题？

当我尝试运行时，错误总是发生

 intron1_length = ((my_dna.find(‘gtcata’)) –
 (my_dna.find(‘atcgat’)))

错误是"-“。只是不确定应该用什么来代替。谢谢!

 # -*- coding: utf-8 -*-

 # We’ll start with “data-aware” way to do this first.
 # Since we have the sequence, we can see that exon 1 ends with
 # ‘GACTA’. We can use that information, and that method, for
 # finding the positions of the elements of this gDNA. This is NOT
 # an elegant solution, and would not work if we didn’t know the
 # DNA sequence ahead of time.

 my_dna = "ATCGATCGATGGTCGAATGACTAgtcatagctatgcatgtagctactc
 gatcgtattttattcgatcgatcgatCGATCGATCATGCTATCATCGATCGATATCGATGCATC
 GACTACTATgtcatggctatgcatcgatcgtattttattcgatcgttcgatGATCGATCGATCGACTGACTTTGAA"   
 # here we introduce another useful operator for strings: len
 gene_length = len(my_dna)
 # we’ll use the starting position of useful substrings in the
 # sequence to find the positions of the exon-intron boundaries.
 # We’ll then use those to find the length of each segment.
 exon1_length = (my_dna.find('Agtcata'))
 intron1_length =((my_dna.find('gtcata')) - (my_dna.find('atcgat')))
 exon2_length = ((my_dna.find('CGATCG'))- (my_dna.find('Tgtcatg')))
 intron2_length = ((my_dna.find('gtcatg'))- (my_dna.find('tGATCGA')))
 exon3_length = (gene_length(my_dna.find('GATCGA'))
 print ("Gene length:" + str(gene_length))
 print ("Exon1 length:" + str(exon1_length))
 print ("Intron1 length:" + str(intron1_length))
 print ("Exon2 length:" + str(exon2_length))
 print ("Intron2 length:" + str(intron2_length))
 print ("Exon2 length:" + str(exon3_length)) 

Answer 1

因为– != -

你用什么来编辑你的代码呢？文字处理器？？

这些引述‘看起来也很可疑。使用不会将这些放入代码中的编辑器。

Answer 2

下面的代码运行时没有错误：

my_dna = """ATCGATCGATGGTCGAATGACTAgtcatagctatgcatgtagctactc
gatcgtattttattcgatcgatcgatCGATCGATCATGCTATCATCGATCGATATCGATGCATC
GACTACTATgtcatggctatgcatcgatcgtattttattcgatcgttcgatGATCGATCGATCGACTGACTTTGAA"""
# here we introduce another useful operator for strings: len
gene_length = len(my_dna)
# we’ll use the starting position of useful substrings in the
# sequence to find the positions of the exon-intron boundaries.
# We’ll then use those to find the length of each segment.
exon1_length = my_dna.find('Agtcata')
intron1_length = my_dna.find('gtcata') - my_dna.find('atcgat')
exon2_length = my_dna.find('CGATCG') - my_dna.find('Tgtcatg')
intron2_length = my_dna.find('gtcatg') - my_dna.find('tGATCGA')
exon3_length = gene_length - my_dna.find('GATCGA')
print ("Gene length:" + str(gene_length))
print ("Exon1 length:" + str(exon1_length))
print ("Intron1 length:" + str(intron1_length))
print ("Exon2 length:" + str(exon2_length))
print ("Intron2 length:" + str(intron2_length))
print ("Exon2 length:" + str(exon3_length))

假设您使用的是Python3，我将括号保留在打印语句中。

要使代码运行，只需要更改两个命令：

• my_dna的定义是一个多行字符串，因此它需要三个引号。另一方面，如果你希望它是一个单行字符串，那么就把它全部放在一行上。
• exon3_length行有两个问题:不平衡的括号和调用整数的尝试。

在修复这些问题之后，代码就会运行。

不需要更改一个即可运行代码。

Answer 3

这是代码中出错的部分：

exon3_length = (gene_length(my_dna.find('GATCGA'))

前面通过在gene_length字符串上调用len将dna定义为整数。