[英]Read from file and write to another python
I have a file with contents as given below,我有一个包含如下内容的文件,
to-56 Olive 850.00 10 10
to-78 Sauce 950.00 25 20
to-65 Green 100.00 6 10
If the 4th column of data is less than or equal to the 5th column, the data should be written to a second file.如果第 4 列数据小于或等于第 5 列,则应将数据写入第二个文件。
I tried the following code, but only 'to-56 Olive' is saved in the second file.我尝试了以下代码,但只有“to-56 Olive”保存在第二个文件中。 I can't figure out what I'm doing wrong here.我无法弄清楚我在这里做错了什么。
file1=open("inventory.txt","r")
file2=open("purchasing.txt","w")
data=file1.readline()
for line in file1:
items=data.strip()
item=items.split()
qty=int(item[3])
reorder=int(item[4])
if qty<=reorder:
file2.write(item[0]+"\t"+item[1]+"\n")
file1.close()
file2.close()
You're reading only one line of input.您只阅读一行输入。 So, you can have at most one line of output.因此,您最多可以有一行输出。
I see that your code is a bit "old school".我看到你的代码有点“老派”。 Here's a more "modern" and Pythonic version.这是一个更“现代”和 Pythonic 的版本。
# Modern way to open files. The closing in handled cleanly
with open('inventory.txt', mode='r') as in_file, \
open('purchasing.txt', mode='w') as out_file:
# A file is iterable
# We can read each line with a simple for loop
for line in in_file:
# Tuple unpacking is more Pythonic and readable
# than using indices
ref, name, price, quantity, reorder = line.split()
# Turn strings into integers
quantity, reorder = int(quantity), int(reorder)
if quantity <= reorder:
# Use f-strings (Python 3) instead of concatenation
out_file.write(f'{ref}\t{name}\n')
I've changed your code a tiny bit, all you need to do is iterate over lines in your file - like this:我已经稍微更改了您的代码,您需要做的就是遍历文件中的行 - 像这样:
file1=open("inventory.txt","r")
file2=open("purchasing.txt","w")
# Iterate over each line in the file
for line in file1.readlines():
# Separate each item in the line
items=line.split()
# Retrieve important bits
qty=int(items[3])
reorder=int(items[4])
# Write to the file if conditions are met
if qty<=reorder:
file2.write(items[0]+"\t"+items[1]+"\n")
# Release used resources
file1.close()
file2.close()
Here is the output in purchasing.txt :这里是purchasing.txt输出:
to-56 Olive
to-65 Green
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