Jelly, 64 60 58 bytes

“¡ŀṪ]ṃ{yṁ“Ñ3$ṘW5Ḍż⁸¢Hŀ“ÑɲʋØƥþƈƘ}»;“.¶“A“If“ a”“ṚøTøṖ’ṃFḊ”?

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How it works (outdated)

“ɱDœɓẆ'ṫ“Ñ3$ṘW5Ḍż⁸¢Hŀ“ÑɲʋØƥþƈƘ}»

The strings ɱDœɓẆ'ṫ, Ñ3$ṘW5Ḍż⁸¢Hŀ, and ÑɲʋØƥþƈƘ} use Jelly's inbuilt dictionary to encode ["Peter Piper picked", " peck of pickled peppers", ",\nWhere's the"].

                                 “.¶“A“ “If “?“ a”

This literal yields the string array [".\n", "A ", "If ", "?", " a"].

                                                  “EiƓ[ẹiV’

This bijective base-250 literal yields 17193938950964087₁₀, which is 102452614710232618₉.

                                ;                          ṃ

Concatenate the string arrays to the left (yielding an array of 9 strings), then use the base-9 digits of the integer to the right to select strings from the array.

Indexing is 1-based and modular, so digits 1 and 0 correspond to the first and last string, respectively.

Jelly, 64 60 58 57 bytes

“¡ŀṪ]ṃ{yṁ“Ñ3$ṘW5Ḍż⁸¢Hŀ»j⁾ a,Ṛẋ2ż“³ḌM“¡FỊİg“ÑɲʋØƥþƈƘ}»FḊ”?

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Jelly, 64 60 bytes

“ɱDœɓẆ'ṫ“Ñ3$ṘW5Ḍż⁸¢Hŀ“ÑɲʋØƥþƈƘ}»;“.¶“A“ “If “?“ a”“EiƓ[ẹiV’ṃ

Try it online!

How it works

“ɱDœɓẆ'ṫ“Ñ3$ṘW5Ḍż⁸¢Hŀ“ÑɲʋØƥþƈƘ}»

The strings ɱDœɓẆ'ṫ, Ñ3$ṘW5Ḍż⁸¢Hŀ, and ÑɲʋØƥþƈƘ} use Jelly's inbuilt dictionary to encode ["Peter Piper picked", " peck of pickled peppers", ",\nWhere's the"].

                                 “.¶“A“ “If “?“ a”

This literal yields the string array [".\n", "A ", "If ", "?", " a"].

                                                  “EiƓ[ẹiV’

This bijective base-250 literal yields 17193938950964087₁₀, which is 102452614710232618₉.

                                ;                          ṃ

Concatenate the string arrays to the left (yielding an array of 9 strings), then use the base-9 digits of the integer to the right to select strings from the array.

Indexing is 1-based and modular, so digits 1 and 0 correspond to the first and last string, respectively.

Jelly, 64 60 58 bytes

“¡ŀṪ]ṃ{yṁ“Ñ3$ṘW5Ḍż⁸¢Hŀ“ÑɲʋØƥþƈƘ}»;“.¶“A“If“ a”“ṚøTøṖ’ṃFḊ”?

Try it online!

How it works (outdated)

“ɱDœɓẆ'ṫ“Ñ3$ṘW5Ḍż⁸¢Hŀ“ÑɲʋØƥþƈƘ}»

The strings ɱDœɓẆ'ṫ, Ñ3$ṘW5Ḍż⁸¢Hŀ, and ÑɲʋØƥþƈƘ} use Jelly's inbuilt dictionary to encode ["Peter Piper picked", " peck of pickled peppers", ",\nWhere's the"].

                                 “.¶“A“ “If “?“ a”

This literal yields the string array [".\n", "A ", "If ", "?", " a"].

                                                  “EiƓ[ẹiV’

This bijective base-250 literal yields 17193938950964087₁₀, which is 102452614710232618₉.

                                ;                          ṃ

Concatenate the string arrays to the left (yielding an array of 9 strings), then use the base-9 digits of the integer to the right to select strings from the array.

Indexing is 1-based and modular, so digits 1 and 0 correspond to the first and last string, respectively.

Jelly, 64 60 bytes

“ɱDœɓẆ'ṫ“Ñ3$ṘW5Ḍż⁸¢Hŀ“ÑɲʋØƥþƈƘ}»;“.¶“A“ “If “?“ a”“EiƓ[ẹiV’ṃ

Try it online!

How it works

“ɱDœɓẆ'ṫ“Ñ3$ṘW5Ḍż⁸¢Hŀ“ÑɲʋØƥþƈƘ}»

The strings ɱDœɓẆ'ṫ, Ñ3$ṘW5Ḍż⁸¢Hŀ, and ÑɲʋØƥþƈƘ} use Jelly's inbuilt dictionary to encode ["Peter Piper picked", " peck of pickled peppers", ",\nWhere's the"].

                                 “.¶“A“ “If “?“ a”

This literal yields the string array [".\n", "A ", "If ", "?", " a"].

                                                  “EiƓ[ẹiV’

This bijective base-250 literal yields 17193938950964087₁₀, which is 102452614710232618₉.

                            ;                          ṃ

Concatenate the string arrays (yielding an array of 9 strings) and use the base-9 digits of the integer to select strings from the array. Indexing is 1-based and modular, so digits 1 and 0 correspond to the first and last string, respectively.

Jelly, 64 60 bytes

“ɱDœɓẆ'ṫ“Ñ3$ṘW5Ḍż⁸¢Hŀ“ÑɲʋØƥþƈƘ}»;“.¶“A“ “If “?“ a”“EiƓ[ẹiV’ṃ

Try it online!

How it works

“ɱDœɓẆ'ṫ“Ñ3$ṘW5Ḍż⁸¢Hŀ“ÑɲʋØƥþƈƘ}»

The strings ɱDœɓẆ'ṫ, Ñ3$ṘW5Ḍż⁸¢Hŀ, and ÑɲʋØƥþƈƘ} use Jelly's inbuilt dictionary to encode ["Peter Piper picked", " peck of pickled peppers", ",\nWhere's the"].

                                 “.¶“A“ “If “?“ a”

This literal yields the string array [".\n", "A ", "If ", "?", " a"].

                                                  “EiƓ[ẹiV’

This bijective base-250 literal yields 17193938950964087₁₀, which is 102452614710232618₉.

                                ;                          ṃ

Concatenate the string arrays to the left (yielding an array of 9 strings), then use the base-9 digits of the integer to the right to select strings from the array. 

Indexing is 1-based and modular, so digits 1 and 0 correspond to the first and last string, respectively.