swift - how to print to console multi line Strings in 2 distinct columns on the screen

问题

I have 2 very long strings which span multiple lines each and want to print to console both strings in their own "column" to the terminal

i.e.

let veryLongStringWithNewLines = "a very long string with \n 
and blah blah \n
and more text ....."


let anotherVeryLongStringWithNewLines = "......."

print ("\(veryLongStringWithNewLines) %???Break Screen in Center???% \(anotherVeryLongStringWithNewLines)") // <<<< TO THE CONSOLE

I want to divide the console into 2 columns such that each string is printed in its own area , but side by side , i.e. EXCEL with 2 columns, each string in its own column

The string should wrap inside of that column to new lines when necessary

Not sure how to achieve this

回答1:

Here's something to get you started:

// Break a string up into an array of Strings, first on newlines
// and then by width if the lines are longer than width
func breakIntoLines(text: String, width: Int) -> [String] {
    var result = [String]()

    for line in text.split(separator: "\n") {
        var str = String(line)
        while str.count > width {
            result.append(String(str.prefix(width)))
            str = String(str.dropFirst(width))
        }

        // pad last line to width to make displaying easier
        result.append(str + String(repeating: " ", count: width - str.count))
    }

    return result
}

// print two Strings in two columns optionally keeping the rows
// in sync
func printIn2Columns(text1: String, text2: String, columnWidth: Int, space: Int, keepRowsInSync: Bool = false) {
    if keepRowsInSync {
        // split the lines into rows on newline
        var rows1 = text1.split(separator: "\n")
        var rows2 = text2.split(separator: "\n")

        // pad the shorter number of rows
        if rows1.count > rows2.count {
            rows2 += Array(repeating: "", count: rows1.count - rows2.count)
        } else if rows2.count > rows1.count {
            rows1 += Array(repeating: "", count: rows2.count - rows1.count)
        }

        // print each row in two columns
        for (row1, row2) in zip(rows1, rows2) {
            printIn2Columns(text1: String(row1), text2: String(row2), columnWidth: columnWidth, space: space)
        }
    } else {
        var column1 = breakIntoLines(text: text1, width: columnWidth)
        var column2 = breakIntoLines(text: text2, width: columnWidth)

        // pad the shorter column with extra rows
        let blankLine = String(repeating: " ", count: columnWidth)
        if column1.count > column2.count {
            column2 += Array(repeating: blankLine, count: column1.count - column2.count)
        } else if column2.count > column1.count {
            column1 += Array(repeating: blankLine, count: column2.count - column1.count)
        }

        let spacing = String(repeating: " ", count: space)

        for (line1, line2) in zip(column1, column2) {
            print("\(line1)\(spacing)\(line2)")
        }
    }
}

Tests:

let text1 = """
This is a test
of the code which
breaks this up into
columns
"""

let text2 = """
Well, here goes nothing!
Does this do what you want?
"""

printIn2Columns(text1: text1, text2: text2, columnWidth: 8, space: 5)

This is      Well, he
a test       re goes 
of the c     nothing!
ode whic     Does thi
h            s do wha
breaks t     t you wa
his up i     nt?     
nto          
columns

printIn2Columns(text1: text2, text2: text1, columnWidth: 10, space: 4)

Well, here    This is a 
 goes noth    test      
ing!          of the cod
Does this     e which   
do what yo    breaks thi
u want?       s up into 
              columns

printIn2Columns(text1: text2, text2: text1, columnWidth: 30, space: 5)

Well, here goes nothing!           This is a test                
Does this do what you want?        of the code which             
                                   breaks this up into           
                                   columns

---

Keeping the rows in sync

If you are comparing two texts, it might be desirable to keep the rows in sync. If you have to wrap a row in one column but not the other, add blank lines to the shorter to keep the rows of the original texts in sync.

let t1 = """
1:
2:
3: this is a really long line 3
4:
5: this is a really long line 5
6:
"""

let t2 = """
one - this is a really long line one
two
three - this is a really long line three
four
five
six
"""

printIn2Columns(text1: t1, text2: t2, columnWidth: 16, space: 5, keepRowsInSync: true)

1:                   one - this is a 
                     really long line
                      one            
2:                   two             
3: this is a rea     three - this is 
lly long line 3      a really long li
                     ne three        
4:                   four            
5: this is a rea     five            
lly long line 5                      
6:                   six

来源：https://stackoverflow.com/questions/57500721/swift-how-to-print-to-console-multi-line-strings-in-2-distinct-columns-on-the