String operations — NumPy v1.15 Manual (original) (raw)
This module provides a set of vectorized string operations for arrays of type numpy.string_ or numpy.unicode_. All of them are based on the string methods in the Python standard library.
String operations¶
| add(x1, x2) | Return element-wise string concatenation for two arrays of str or unicode. |
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| multiply(a, i) | Return (a * i), that is string multiple concatenation, element-wise. |
| mod(a, values) | Return (a % i), that is pre-Python 2.6 string formatting (iterpolation), element-wise for a pair of array_likes of str or unicode. |
| capitalize(a) | Return a copy of a with only the first character of each element capitalized. |
| center(a, width[, fillchar]) | Return a copy of a with its elements centered in a string of length width. |
| decode(a[, encoding, errors]) | Calls str.decode element-wise. |
| encode(a[, encoding, errors]) | Calls str.encode element-wise. |
| join(sep, seq) | Return a string which is the concatenation of the strings in the sequence seq. |
| ljust(a, width[, fillchar]) | Return an array with the elements of a left-justified in a string of length width. |
| lower(a) | Return an array with the elements converted to lowercase. |
| lstrip(a[, chars]) | For each element in a, return a copy with the leading characters removed. |
| partition(a, sep) | Partition each element in a around sep. |
| replace(a, old, new[, count]) | For each element in a, return a copy of the string with all occurrences of substring old replaced by new. |
| rjust(a, width[, fillchar]) | Return an array with the elements of a right-justified in a string of length width. |
| rpartition(a, sep) | Partition (split) each element around the right-most separator. |
| rsplit(a[, sep, maxsplit]) | For each element in a, return a list of the words in the string, using sep as the delimiter string. |
| rstrip(a[, chars]) | For each element in a, return a copy with the trailing characters removed. |
| split(a[, sep, maxsplit]) | For each element in a, return a list of the words in the string, using sep as the delimiter string. |
| splitlines(a[, keepends]) | For each element in a, return a list of the lines in the element, breaking at line boundaries. |
| strip(a[, chars]) | For each element in a, return a copy with the leading and trailing characters removed. |
| swapcase(a) | Return element-wise a copy of the string with uppercase characters converted to lowercase and vice versa. |
| title(a) | Return element-wise title cased version of string or unicode. |
| translate(a, table[, deletechars]) | For each element in a, return a copy of the string where all characters occurring in the optional argument deletechars are removed, and the remaining characters have been mapped through the given translation table. |
| upper(a) | Return an array with the elements converted to uppercase. |
| zfill(a, width) | Return the numeric string left-filled with zeros |
Comparison¶
Unlike the standard numpy comparison operators, the ones in the _char_module strip trailing whitespace characters before performing the comparison.
| equal(x1, x2) | Return (x1 == x2) element-wise. |
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| not_equal(x1, x2) | Return (x1 != x2) element-wise. |
| greater_equal(x1, x2) | Return (x1 >= x2) element-wise. |
| less_equal(x1, x2) | Return (x1 <= x2) element-wise. |
| greater(x1, x2) | Return (x1 > x2) element-wise. |
| less(x1, x2) | Return (x1 < x2) element-wise. |
String information¶
| count(a, sub[, start, end]) | Returns an array with the number of non-overlapping occurrences of substring sub in the range [start, _end_]. |
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| find(a, sub[, start, end]) | For each element, return the lowest index in the string where substring sub is found. |
| index(a, sub[, start, end]) | Like find, but raises ValueError when the substring is not found. |
| isalpha(a) | Returns true for each element if all characters in the string are alphabetic and there is at least one character, false otherwise. |
| isdecimal(a) | For each element, return True if there are only decimal characters in the element. |
| isdigit(a) | Returns true for each element if all characters in the string are digits and there is at least one character, false otherwise. |
| islower(a) | Returns true for each element if all cased characters in the string are lowercase and there is at least one cased character, false otherwise. |
| isnumeric(a) | For each element, return True if there are only numeric characters in the element. |
| isspace(a) | Returns true for each element if there are only whitespace characters in the string and there is at least one character, false otherwise. |
| istitle(a) | Returns true for each element if the element is a titlecased string and there is at least one character, false otherwise. |
| isupper(a) | Returns true for each element if all cased characters in the string are uppercase and there is at least one character, false otherwise. |
| rfind(a, sub[, start, end]) | For each element in a, return the highest index in the string where substring sub is found, such that sub is contained within [start, _end_]. |
| rindex(a, sub[, start, end]) | Like rfind, but raises ValueError when the substring sub is not found. |
| startswith(a, prefix[, start, end]) | Returns a boolean array which is True where the string element in a starts with prefix, otherwise False. |
Convenience class¶
| chararray(shape[, itemsize, unicode, …]) | Provides a convenient view on arrays of string and unicode values. |
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