[英]Using readlines in python? First time
I have a text file with columns of data and I need to turn these columns into individual lists or arrays. 我有一个包含数据列的文本文件,我需要将这些列转换为单独的列表或数组。 This is what I have so far
这就是我到目前为止所拥有的
f = open('data.txt', 'r')
temp = []
for row in f.readlines():
Data = row.split()
temp.append(float(Data[0]))
When I run this I get IndexError: list index out of range
. 当我运行这个时,我得到
IndexError: list index out of range
。
Snippet of the data below: 下面的数据片段:
16 0.2000
17 0.3000
18 0.4000
20 0.5000
21 0.6000
22 0.7000
24 0.8000
25 0.9000
26 1.000
I need the first column, if possible to look like this: Data = [16, 17, 18, 20, 21, 22, 24, 25, 26] 我需要第一列,如果可能的话,看起来像这样:数据= [16,17,18,20,21,22,24,25,26]
You are getting an empty list Data=[]
if you read an empty row. 如果您读取空行,则会获得一个空列表
Data=[]
。 You try to get the first element from the list using Data[0]
,but because it's an empty list it doesn't have an element at position 0, so you get an IndexError
. 您尝试使用
Data[0]
从列表中获取第一个元素,但因为它是一个空列表,它在位置0没有元素,所以您得到一个IndexError
。
Data=''.split()
Data[0]
---------------------------------------------------------------------------
IndexError Traceback (most recent call last)
<ipython-input-686-0792b03cbbdf> in <module>()
----> 1 Data[0]
IndexError: list index out of range
This will print out the Data
if IndexError
occours - you can see yourself that it prints an empty list: 如果
IndexError
出现,这将打印出Data
- 您可以看到它打印一个空列表:
f=open('file','r')
temp = []
for row in f.readlines():
Data = row.split()
try:
temp.append(float(Data[0]))
except IndexError:
print Data
You can use the with
statement to open the file, that automatically closes the file after being processed. 您可以使用
with
语句打开文件,该文件在处理后自动关闭文件。 Also you can loop over the file itself, without using readlines()
. 您也可以循环遍历文件本身,而不使用
readlines()
。
with open(file,'r') as f:
for row in f:
Data = row.split()
try:
print Data[0]
except IndexError:
print 'You have an empty row'
EDIT: You are better of using the csv module: 编辑:你最好使用csv模块:
import csv
with open('file.csv', 'rb') as f:
reader = csv.reader(f, delimiter=' ')
print [row[0] for row in reader if len(row)]
>>>
['16', '17', '18', '20', '21', '22', '24', '25', '26']
use with for filehandlers. 用于文件处理程序。
with open('path/to/file', 'r') as f:
for line in f:
# code.
you index error comes from trying to access Data
at the [0]
location. 您指数错误来自试图访问
Data
在[0]
位置。 which simply means your line was empty. 这只是意味着你的线是空的。
you should run a quick check before parsing the line... 你应该在分析线之前快速检查一下......
if len(Data):
#code
else:
#empty line?
f = open('data.txt', 'r')
temp = []
for row in f.readlines():
items = row.split(',')
temp.append(unicode(items[0]))
I hope that it solves your problem. 我希望它能解决你的问题。
def cal(num_list):
x = 1;
z = 0;
while True:
list1 = list(str(x))
list2 = [int(a) for a in list1]
for i in range(len(list2)):
for j in range(10):
if(list2.count(j) > num_list[list2[i]]):
z = 1;
break;
if(z == 1):
save(x);
break;
x = x + 1;
#matrix A to B
def show():
global string_final,list_2,tot
index=matrix_1.index(num) # finding index of num
length=n
j=(index)%length # the column positon
i=index/length # the row position
list_1=[]
for a in range(length):
lis=[]
for b in range(length):
lis.append(matrix_1.pop(0)) #pop the first element and append the list
list_1.append(lis)
tot=0
list_2=[]
for a in range(i+1):
for b in range(j+1):
tot=tot+list_1[a][b] # add the numbers
list_2.append(list_1[a][b]) #append to list
if(b!=length):
list_2.append(" ") #append space
list_2.append("\n")
string_final="".join([str(a) for a in list_2]) #list to string
print "matrix B\n",string_final,"\nx: ",str(num),"\nn: ",str(n)+"\ntotal: "+str(tot) # print the result
#matrix add zero
def get():
global b_no
num_list=[];
file=open("matrix.txt","r");
for i in file:
b_no=0
if(len(i.split())==1): #check length is 1 or not
n=int(i)#string to int
else:
temp=i.split();
if(len(temp)!=n):
b_no+=1
break
temp=[0]+[int(a) for a in temp]+[0] #add zero at first and last
num_list.append(temp);
zero_list=[]
for i in range(n+2):
zero_list.append(0) #append zero
num_list.insert(0,zero_list)
num_list.insert(n+1,zero_list)
return num_list,n;
我会避免使用Data [0]或row [0],而是使用''.join(Data)或'.join(row)来避免空列表(列表索引超出范围错误)。
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