A few days ago, a small partner asked a question about Python reading the first column of data in multiple CSV files in the folder and finding the maximum and minimum values. The discussion is still quite intense. Here are two summary This is a method, and I hope that some friends who encounter this problem can avoid detours. (Video tutorials for each stage of Python are attached at the end of the article, you can find me a free prostitute)
/1. Problem description/
If you want to find the maximum or minimum value in CSV or Excel, we can find it with the help of the built-in functions max() and min() in Excel. If it's just one or two files, it's definitely a piece of cake to process. When the number of files reaches hundreds, if you follow this method again, it will take time and effort, and you will get half the effort.
But white panic, for the multiple CSV files in the figure below, we can use Python to traverse and read multiple files at once, and then process the files separately, which is twice the result with half the effort.
/Two, the solution/
1. First, let's take a look at the content of the file, here is the content of one of the files, as shown in the figure below.
Of course, this is only a small part of the content of the file, and the actual amount of data is definitely not 21.
2. Now we want to operate on the data in the first column or the second column. Take the maximum and minimum values as an example. Here, the first column is the target data for evaluation.
Usually we use Python to process data. The two most used libraries are numpy and pandas. In this article, we will use the two libraries to operate.
3. The pandas library is used to read the first column of data in multiple CSV files in the folder and find the maximum and minimum values as shown in the figure below.
4. The result obtained through the pandas library is shown in the figure below.
With this method, you can quickly get the maximum and minimum values in the first column of all files in the folder.
5. The code below uses the numpy library to read the first column of data in multiple CSV files in the folder and find the maximum and minimum values as shown in the figure below.
6. The result obtained through the numpy library is shown in the figure below.
Through this method, you can also quickly get the maximum and minimum values in the first column of all files in the folder.
/summary/
This article is based on Python, using the numpy library and pandas library to read multiple CSV files in the folder, and find the maximum and minimum values of the first column of data in the file. Of course, in addition to these two methods, there must be Other methods can also be done, and you are welcome to actively discuss it.
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For those who are interested in learning Python, or want to improve their Python programming skills, you can find me for a tutorial (reply: Python) ~~~ Selfless for you~
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