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Compare two CSV files and find common or different data

 

For Example,there are two text files. Each row of both files is a string. We want to compare them row by row. To do this, we read in each row of every file as a string to form a set of strings and then perform a set operation.

paint.txt and dance.txt record IDs and names of children who enrolled in painting class and dancing class respectively. Below is part of paint.txt:

  20121102-Joan
  20121107-Jack
  20121113-Mike

Find common data

To find common records of the two files is to get their intersection.

Example: Find all children who enrolled in both painting class and dancing class and write their records to result.xlsx.

esProc SPL script:

+ A B
1 =file(“e:/txt/paint.txt”).read@n() Read each of the rows from paint.txt to form a set
2 =file(“e:/txt/dance.txt”).read@n() Read each of the rows from dance.txt to form a set
3 >file(“d:/result.xlsx”).xlsexport(A1^A2;“common”) Write their intersection to result.xlsx

Find differences

Find all different records of the two files.

Example: Find the children who enrolled in either painting class or dancing class.

esProc SPL script:

+ A B
1 =file(“e:/txt/paint.txt”).read@n() Read each of the rows from paint.txt to form a set
2 =file(“e:/txt/dance.txt”).read@n() Read each of the rows from dance.txt to form a set
3 >file(“d:/result.xlsx”).xlsexport@t(A1%A2;“differences”) Write their XORs to result.xlsx

Comparing two text files to find their common or different data is not a rare thing in data analysis work. According to the content to be compared, there are row-wise comparison and comparison by key field(s); and according to the sizes of files under comparison, there are small files comparison and big files comparison. For more details, see Samples of Comparing Files and know more about esProc and SPL

 
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