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Merged
merged 11 commits into from
Jul 5, 2021
Merged

implemented pad function #441

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3c9f8bb
implemented pad function with optional pad_with argument
aman-godara Jun 21, 2021
61f08d9
made argument pad_with non-optional to solve ambiguous interface error
aman-godara Jun 21, 2021
e70f6d8
changed interface to keep pad_with as optional
aman-godara Jun 23, 2021
592c2ca
improved padr_char_default based upon fortran standards
aman-godara Jun 26, 2021
b0fbf5d
removed pad_char_char function
aman-godara Jun 26, 2021
e66abc1
added test cases for padl and padr
aman-godara Jun 28, 2021
7bc4b3a
documented padl and padr functions
aman-godara Jun 29, 2021
39eec81
added comments to explain the right padding and shifted RHS completel…
aman-godara Jul 4, 2021
7ed6fa0
Merge branch 'count' into pad
aman-godara Jul 4, 2021
0b91973
added specification links in comments
aman-godara Jul 4, 2021
74bb5ba
Merge branch 'pad' of https://github.com/Aman-Godara/stdlib into pad
aman-godara Jul 4, 2021
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108 changes: 108 additions & 0 deletions doc/specs/stdlib_strings.md
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Expand Up @@ -384,6 +384,114 @@ end program demo_replace_all
```


<!-- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -->
### `padl`

#### Description

Returns a string of length `output_length` left padded with `pad_with` character if it is provided, otherwise with `" "` (1 whitespace).
If `output_length` is less than or equal to the length of `string`, padding is not performed.

#### Syntax

`string = [[stdlib_strings(module):padl(interface)]] (string, output_length [, pad_with])`

#### Status

Experimental

#### Class

Pure function

#### Argument

- `string`: Character scalar or [[stdlib_string_type(module):string_type(type)]].
This argument is intent(in).
- `output_length`: integer.
This argument is intent(in).
- `pad_with`: Character scalar of length 1.
This argument is intent(in) and optional.

#### Result value

The result is of the same type as `string`.

#### Example

```fortran
program demo_padl
use stdlib_string_type, only: string_type, assignment(=)
use stdlib_strings, only : padl
implicit none
string_type :: string

string = "left pad this string"
! string <-- "left pad this string"

print *, padl(string, 25, "$") ! "$$$$$left pad this string"

string = padl(string, 25)
! string <-- " left pad this string"

end program demo_padl
```


<!-- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -->
### `padr`

#### Description

Returns a string of length `output_length` right padded with `pad_with` character if it is provided, otherwise with `" "` (1 whitespace).
If `output_length` is less than or equal to the length of `string`, padding is not performed.

#### Syntax

`string = [[stdlib_strings(module):padr(interface)]] (string, output_length [, pad_with])`

#### Status

Experimental

#### Class

Pure function

#### Argument

- `string`: Character scalar or [[stdlib_string_type(module):string_type(type)]].
This argument is intent(in).
- `output_length`: integer.
This argument is intent(in).
- `pad_with`: Character scalar of length 1.
This argument is intent(in) and optional.

#### Result value

The result is of the same type as `string`.

#### Example

```fortran
program demo_padr
use stdlib_string_type, only: string_type, assignment(=)
use stdlib_strings, only : padr
implicit none
string_type :: string

string = "right pad this string"
! string <-- "right pad this string"

print *, padr(string, 25, "$") ! "right pad this string$$$$"

string = padr(string, 25)
! string <-- "right pad this string "

end program demo_padr
```


<!-- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -->
### `count`

Expand Down
147 changes: 145 additions & 2 deletions src/stdlib_strings.f90
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Expand Up @@ -5,14 +5,14 @@
!> The specification of this module is available [here](../page/specs/stdlib_strings.html).
module stdlib_strings
use stdlib_ascii, only: whitespace
use stdlib_string_type, only: string_type, char, verify
use stdlib_string_type, only: string_type, char, verify, repeat, len
use stdlib_optval, only: optval
implicit none
private

public :: strip, chomp
public :: starts_with, ends_with
public :: slice, find, replace_all, count
public :: slice, find, replace_all, padl, padr, count


!> Remove leading and trailing whitespace characters.
Expand Down Expand Up @@ -93,6 +93,28 @@ module stdlib_strings
module procedure :: replace_all_char_char_char
end interface replace_all

!> Version: experimental
!>
!> Left pad the input string
!> [Specifications](../page/specs/stdlib_strings.html#padl)
interface padl
module procedure :: padl_string_default
module procedure :: padl_string_pad_with
module procedure :: padl_char_default
module procedure :: padl_char_pad_with
end interface padl

!> Version: experimental
!>
!> Right pad the input string
!> [Specifications](../page/specs/stdlib_strings.html#padr)
interface padr
module procedure :: padr_string_default
module procedure :: padr_string_pad_with
module procedure :: padr_char_default
module procedure :: padr_char_pad_with
end interface padr

!> Version: experimental
!>
!> Returns the number of times substring 'pattern' has appeared in the
Expand Down Expand Up @@ -659,6 +681,127 @@ pure function replace_all_char_char_char(string, pattern, replacement) result(re

end function replace_all_char_char_char

!> Left pad the input string with " " (1 whitespace)
!>
!> Returns a new string
pure function padl_string_default(string, output_length) result(res)
type(string_type), intent(in) :: string
integer, intent(in) :: output_length
type(string_type) :: res

res = string_type(padl(char(string), output_length, " "))

end function padl_string_default

!> Left pad the input string with the 'pad_with' character
!>
!> Returns a new string
pure function padl_string_pad_with(string, output_length, pad_with) result(res)
type(string_type), intent(in) :: string
integer, intent(in) :: output_length
character(len=1), intent(in) :: pad_with
type(string_type) :: res

res = string_type(padl(char(string), output_length, pad_with))

end function padl_string_pad_with

!> Left pad the input string with " " (1 whitespace)
!>
!> Returns a new string
pure function padl_char_default(string, output_length) result(res)
character(len=*), intent(in) :: string
integer, intent(in) :: output_length
character(len=max(len(string), output_length)) :: res

res = padl(string, output_length, " ")

end function padl_char_default

!> Left pad the input string with the 'pad_with' character
!>
!> Returns a new string
pure function padl_char_pad_with(string, output_length, pad_with) result(res)
character(len=*), intent(in) :: string
integer, intent(in) :: output_length
character(len=1), intent(in) :: pad_with
character(len=max(len(string), output_length)) :: res
integer :: string_length

string_length = len(string)

if (string_length < output_length) then
res = repeat(pad_with, output_length - string_length)
res(output_length - string_length + 1 : output_length) = string
else
res = string
end if

end function padl_char_pad_with

!> Right pad the input string with " " (1 whitespace)
!>
!> Returns a new string
pure function padr_string_default(string, output_length) result(res)
type(string_type), intent(in) :: string
integer, intent(in) :: output_length
character(len=max(len(string), output_length)) :: char_output
type(string_type) :: res

! We're taking advantage of `char_output` being longer than `string` and
! initialized with whitespaces. By casting `string` to a `character`
! type and back to `string_type`, we're effectively right-padding
! `string` with spaces, so we don't need to pad explicitly.
char_output = char(string)
res = string_type(char_output)

end function padr_string_default

!> Right pad the input string with the 'pad_with' character
!>
!> Returns a new string
pure function padr_string_pad_with(string, output_length, pad_with) result(res)
type(string_type), intent(in) :: string
integer, intent(in) :: output_length
character(len=1), intent(in) :: pad_with
type(string_type) :: res

res = string_type(padr(char(string), output_length, pad_with))

end function padr_string_pad_with

!> Right pad the input string with " " (1 whitespace)
!>
!> Returns a new string
pure function padr_char_default(string, output_length) result(res)
character(len=*), intent(in) :: string
integer, intent(in) :: output_length
character(len=max(len(string), output_length)) :: res

res = string

end function padr_char_default

!> Right pad the input string with the 'pad_with' character
!>
!> Returns a new string
pure function padr_char_pad_with(string, output_length, pad_with) result(res)
character(len=*), intent(in) :: string
integer, intent(in) :: output_length
character(len=1), intent(in) :: pad_with
character(len=max(len(string), output_length)) :: res
integer :: string_length

string_length = len(string)

res = string
if (string_length < output_length) then
res(string_length + 1 : output_length) = &
repeat(pad_with, output_length - string_length)
end if

end function padr_char_pad_with

!> Returns the number of times substring 'pattern' has appeared in the
!> input string 'string'
!> Returns an integer
Expand Down
78 changes: 77 additions & 1 deletion src/tests/string/test_string_functions.f90
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Original file line number Diff line number Diff line change
Expand Up @@ -4,7 +4,7 @@ module test_string_functions
use stdlib_error, only : check
use stdlib_string_type, only : string_type, assignment(=), operator(==), &
to_lower, to_upper, to_title, to_sentence, reverse
use stdlib_strings, only: slice, find, replace_all, count
use stdlib_strings, only: slice, find, replace_all, padl, padr, count
use stdlib_optval, only: optval
use stdlib_ascii, only : to_string
implicit none
Expand Down Expand Up @@ -378,6 +378,80 @@ subroutine test_replace_all

end subroutine test_replace_all

subroutine test_padl
type(string_type) :: test_string
character(len=:), allocatable :: test_char

test_string = "left pad this string"
test_char = " left pad this string "

! output_length > len(string)
call check(padl(test_string, 25, "#") == "#####left pad this string", &
& 'padl: output_length > len(string), test_case 1')
call check(padl(test_string, 22, "$") == "$$left pad this string", &
& 'padl: output_length > len(string), test_case 2')
call check(padl(test_string, 23) == " left pad this string", &
& 'padl: output_length > len(string), test_case 3')
call check(padl(test_char, 26) == " left pad this string ", &
& 'padl: output_length > len(string), test_case 4')
call check(padl(test_char, 26, "&") == "&& left pad this string ", &
& 'padl: output_length > len(string), test_case 5')
call check(padl("", 10, "!") == "!!!!!!!!!!", &
& 'padl: output_length > len(string), test_case 6')

! output_length <= len(string)
call check(padl(test_string, 18, "#") == "left pad this string", &
& 'padl: output_length <= len(string), test_case 1')
call check(padl(test_string, -4, "@") == "left pad this string", &
& 'padl: output_length <= len(string), test_case 2')
call check(padl(test_char, 20, "0") == " left pad this string ", &
& 'padl: output_length <= len(string), test_case 3')
call check(padl(test_char, 17) == " left pad this string ", &
& 'padl: output_length <= len(string), test_case 4')
call check(padl("", 0, "!") == "", &
& 'padl: output_length <= len(string), test_case 5')
call check(padl("", -12, "!") == "", &
& 'padl: output_length <= len(string), test_case 6')

end subroutine test_padl

subroutine test_padr
type(string_type) :: test_string
character(len=:), allocatable :: test_char

test_string = "right pad this string"
test_char = " right pad this string "

! output_length > len(string)
call check(padr(test_string, 25, "#") == "right pad this string####", &
& 'padr: output_length > len(string), test_case 1')
call check(padr(test_string, 22, "$") == "right pad this string$", &
& 'padr: output_length > len(string), test_case 2')
call check(padr(test_string, 24) == "right pad this string ", &
& 'padr: output_length > len(string), test_case 3')
call check(padr(test_char, 27) == " right pad this string ", &
& 'padr: output_length > len(string), test_case 4')
call check(padr(test_char, 27, "&") == " right pad this string &&", &
& 'padr: output_length > len(string), test_case 5')
call check(padr("", 10, "!") == "!!!!!!!!!!", &
& 'padr: output_length > len(string), test_case 6')

! output_length <= len(string)
call check(padr(test_string, 18, "#") == "right pad this string", &
& 'padr: output_length <= len(string), test_case 1')
call check(padr(test_string, -4, "@") == "right pad this string", &
& 'padr: output_length <= len(string), test_case 2')
call check(padr(test_char, 20, "0") == " right pad this string ", &
& 'padr: output_length <= len(string), test_case 3')
call check(padr(test_char, 17) == " right pad this string ", &
& 'padr: output_length <= len(string), test_case 4')
call check(padr("", 0, "!") == "", &
& 'padr: output_length <= len(string), test_case 5')
call check(padr("", -12, "!") == "", &
& 'padr: output_length <= len(string), test_case 6')

end subroutine test_padr

subroutine test_count
type(string_type) :: test_string_1, test_string_2, test_pattern_1, test_pattern_2
test_string_1 = "DNA sequence: AGAGAGAGTCCTGTCGAGA"
Expand Down Expand Up @@ -437,6 +511,8 @@ program tester
call test_slice_gen
call test_find
call test_replace_all
call test_padl
call test_padr
call test_count

end program tester