Project Euler Problem 8 requires a lot of string manipulation. Still we have some opportunities to practice our NumPy skills.

**1. Calculate the product of the 5 element array**

First we need to compute the product of an array with 5 elements. We can calculate the product of the elements in an array with the NumPy prod function.

1 | products.append(digits[i:i + 5].prod()) |

**2. Get the max of the products**

The products are stored in a Python list. We can convert this to a NumPy array and then find the greatest product with the NumPy max function.

1 | print numpy.array(products).max() |

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 | import numpy #Find the greatest product of five consecutive digits in the 1000-digit number. number = "73167176531330624919225119674426574742355349194934\ 96983520312774506326239578318016984801869478851843\ 85861560789112949495459501737958331952853208805511\ 12540698747158523863050715693290963295227443043557\ 66896648950445244523161731856403098711121722383113\ 62229893423380308135336276614282806444486645238749\ 30358907296290491560440772390713810515859307960866\ 70172427121883998797908792274921901699720888093776\ 65727333001053367881220235421809751254540594752243\ 52584907711670556013604839586446706324415722155397\ 53697817977846174064955149290862569321978468622482\ 83972241375657056057490261407972968652414535100474\ 82166370484403199890008895243450658541227588666881\ 16427171479924442928230863465674813919123162824586\ 17866458359124566529476545682848912883142607690042\ 24219022671055626321111109370544217506941658960408\ 07198403850962455444362981230987879927244284909188\ 84580156166097919133875499200524063689912560717606\ 05886116467109405077541002256983155200055935729725\ 71636269561882670428252483600823257530420752963450" digits = numpy.zeros(1000) for i in xrange(len(number)): digits[i] = int(number[i]) products = [] for i in xrange(len(digits) - 5): #1. Calculate the product of the 5 element array products.append(digits[i:i + 5].prod()) #2. Get the max of the products print numpy.array(products).max() |

If you liked this post and are interested in NumPy check out NumPy Beginner’s Guide by yours truly.