jstreams 1.0.5

A package providing streams and optional functionality similar to Java streams and optionals.

jstreams

jstreams is a Python library aiming to replicate the Java Streams and Optional functionality. The library is implemented with type safety in mind.

Installation

Use the package manager pip to install jstream.

pip install jstream

Usage

from jstream import Stream

# Applies a mapping function on each element then produces a new string
print(Stream(["Test", "Best", "Lest"]).map(str.upper).collect())
# will output ["TEST", "BEST", "LEST"]

# Filter the stream elements
print(Stream(["Test", "Best", "Lest"])
            .filter(lambda s: s.startswith("T"))
            .collect())
# Will output ['Test']

# isNotEmpty checks if the stream is empty
print(Stream(["Test", "Best", "Lest"])
            .filter(lambda s: s.startswith("T"))
            .isNotEmpty())
# Will output True

# Checks if all elements match a given condition
print(Stream(["Test", "Best", "Lest"]).allMatch(lambda s: s.endswith("est")))
# Will output True

print(Stream(["Test", "Best", "Lest"]).allMatch(lambda s: s.startswith("T")))
# Will output False

# Checks if any element matches a given condition
print(Stream(["Test", "Best", "Lest"]).anyMatch(lambda s: s.startswith("T")))
# Will output True

# Checks if no elements match the given condition
print(Stream(["Test", "Best", "Lest"]).noneMatch(lambda s: s.startswith("T")))
# Will output False

# Gets the first value of the stream as an Opt (optional object)
print(Stream(["Test", "Best", "Lest"])
            .findFirst(lambda s: s.startswith("L"))
            .getActual())
# Will output "Lest"

# Returns the first element in the stream
print(Stream(["Test", "Best", "Lest"]).first())
# Will output "Test"

# cast casts the elements to a different type. Useful if you have a stream
# of base objects and want to get only those of a super class
print(Stream(["Test1", "Test2", 1, 2])
            .filter(lambda el: el == "Test1")
            # Casts the filtered elements to the given type
            .cast(str)
            .first())
# Will output "Test1"

# If the stream elements are Iterables, flatMap will produce a list of all contained items
print(Stream([["a", "b"], ["c", "d"]]).flatMap(list).toList())
# Will output ["a", "b", "c", "d"]

# reduce will produce a single value, my applying the comparator function given as parameter
# in order to decide which value is higher. The comparator function is applied on subsequent elements
# and only the 'highest' one will be kept
print(Stream([1, 2, 3, 4, 20, 5, 6]).reduce(max).getActual())
# Will output 20

# notNull returns a new stream containing only non null elements
print(Stream(["A", None, "B", None, None, "C", None, None]).nonNull().toList())
# Will output ["A", "B", "C"]

License

MIT